Tropics https://climatedataguide.ucar.edu/ en Asymmetry and Diversity in the pattern, amplitude and duration of El Niño and La Niña https://climatedataguide.ucar.edu/climate-data/asymmetry-and-diversity-pattern-amplitude-and-duration-el-ni%25C3%25B1o-and-la-ni%25C3%25B1a <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--climate-dataset--rss--title.html.twig * field--node--title--rss.html.twig * field--node--climate-dataset--title.html.twig * field--node--title--climate-dataset.html.twig x field--node--title.html.twig * field--node--climate-dataset.html.twig * field--title.html.twig * field--string.html.twig * field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--node--title.html.twig' --> <span class="field field--name-title field--type-string field--label-hidden">Asymmetry and Diversity in the pattern, amplitude and duration of El Niño and La Niña</span> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--node--title.html.twig' --> <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--climate-dataset--rss--uid.html.twig * field--node--uid--rss.html.twig * field--node--climate-dataset--uid.html.twig * field--node--uid--climate-dataset.html.twig x field--node--uid.html.twig * field--node--climate-dataset.html.twig * field--uid.html.twig * field--entity-reference.html.twig * field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--node--uid.html.twig' --> <span class="field field--name-uid field--type-entity-reference field--label-hidden"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'username' --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/user/username.html.twig' --> <span lang="" about="/user/2" typeof="schema:Person" property="schema:name" datatype="">ryanj</span> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/user/username.html.twig' --> </span> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--node--uid.html.twig' --> <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--climate-dataset--rss--created.html.twig * field--node--created--rss.html.twig * field--node--climate-dataset--created.html.twig * field--node--created--climate-dataset.html.twig x field--node--created.html.twig * field--node--climate-dataset.html.twig * field--created.html.twig * field--created.html.twig * field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--node--created.html.twig' --> <span class="field field--name-created field--type-created field--label-hidden">Mon, 01/20/2020 - 09:49</span> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--node--created.html.twig' --> <!-- THEME DEBUG --> <!-- THEME HOOK: 'layout__twocol_section' --> <!-- FILE NAME SUGGESTIONS: x layout--twocol-section.html.twig x layout--twocol-section.html.twig * layout.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/layout/layout--twocol-section.html.twig' --> <div> <div class="layout__region layout__region--main-top breadcrumb-wrapper mt-2"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'block' --> <!-- FILE NAME SUGGESTIONS: * block--system-breadcrumb-block.html.twig * block--system.html.twig x block.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> <div class="block block-system block-system-breadcrumb-block"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'breadcrumb' --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/navigation/breadcrumb.html.twig' --> <nav class="mb-2 d-print-none" role="navigation" aria-labelledby="system-breadcrumb"> <h2 id="system-breadcrumb" class="visually-hidden">Breadcrumb</h2> <ol class="breadcrumb"> <li class="breadcrumb-item"> <a href="/">Home</a> </li> <li class="breadcrumb-item"> <a href="/domains/tropics">Tropics</a> </li> </ol> </nav> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/navigation/breadcrumb.html.twig' --> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> </div> <main class="layout__region layout__region--main main-content-wrapper"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'block' --> <!-- FILE NAME SUGGESTIONS: * block--field-block--field-primary-image.html.twig * block--field-block--node--climate-dataset--field-primary-image.html.twig * block--field-block--node--climate-dataset.html.twig * block--field-block--node.html.twig * block--field-block.html.twig * block--layout-builder.html.twig x block.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> <div class="block block-layout-builder block-field-blocknodeclimate-datasetfield-primary-image"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--climate-dataset---custom--field-primary-image.html.twig * field--node--field-primary-image---custom.html.twig * field--node--climate-dataset--field-primary-image.html.twig * field--node--field-primary-image--climate-dataset--default.html.twig * field--node--field-primary-image--climate-dataset.html.twig * field--node--field-primary-image.html.twig * field--node--climate-dataset.html.twig * field--field-primary-image.html.twig * field--entity-reference.html.twig x field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field.html.twig' --> <div class="field field--name-field-primary-image field--type-entity-reference field--label-visually_hidden"> <div class="field__label visually-hidden">Teaser image</div> <div class="field__item"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'image_formatter' --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/image-formatter.html.twig' --> <!-- THEME DEBUG --> <!-- THEME HOOK: 'image' --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/image.html.twig' --> <img src="/sites/default/files/2022-03/Santoso-snippet.png" width="705" height="695" alt="Asymmetry and Diversity in the pattern, amplitude and duration of El Niño and La Niña" loading="lazy" typeof="foaf:Image" class="img-fluid" /> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/image.html.twig' --> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/image-formatter.html.twig' --> </div> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field.html.twig' --> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> <!-- THEME DEBUG --> <!-- THEME HOOK: 'block' --> <!-- FILE NAME SUGGESTIONS: x block--field-block--field-main-content.html.twig * block--field-block--node--climate-dataset--field-main-content.html.twig * block--field-block--node--climate-dataset.html.twig * block--field-block--node.html.twig * block--field-block.html.twig * block--layout-builder.html.twig * block.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block--field-block--field-main-content.html.twig' --> <div class="mt-3 mt-md-4 block block-layout-builder block-field-blocknodeclimate-datasetfield-main-content"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--climate-dataset---custom--field-main-content.html.twig * field--node--field-main-content---custom.html.twig * field--node--climate-dataset--field-main-content.html.twig * field--node--field-main-content--climate-dataset--default.html.twig * field--node--field-main-content--climate-dataset.html.twig * field--node--field-main-content.html.twig * field--node--climate-dataset.html.twig * field--field-main-content.html.twig * field--entity-reference-revisions.html.twig x field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field.html.twig' --> <div class="field field--name-field-main-content field--type-entity-reference-revisions field--label-visually_hidden"> <div class="field__label visually-hidden">Main content</div> <div class="field__items"> <div class="field__item"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'paragraph' --> <!-- FILE NAME SUGGESTIONS: * paragraph--climate-dataset--rich-text.html.twig * paragraph--rich-text--.html.twig * paragraph--rich-text--default.html.twig * paragraph--rich-text.html.twig * paragraph--default.html.twig x paragraph.html.twig --> <!-- BEGIN OUTPUT from 'modules/composer/paragraphs/templates/paragraph.html.twig' --> <div class="paragraph paragraph--type--rich-text paragraph--view-mode--default"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--paragraph--field-body--default--climate-dataset.html.twig * field--rich-text--default--field-body.html.twig * field--paragraph--field-body--default.html.twig * field--paragraph--rich-text--field-body.html.twig * field--paragraph--field-body--rich-text.html.twig * field--paragraph--field-body.html.twig * field--paragraph--rich-text.html.twig * field--field-body.html.twig x field--text-long.html.twig * field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--text-long.html.twig' --> <div class="clearfix text-formatted field field--name-field-body field--type-text-long field--label-hidden field__item"><p>El Niño and La Niña, the two phases of ENSO, are sometimes described as opposites. However, there are asymmetries in their spatial structure, amplitude, duration and seasonal evolution. This leads to differing teleconnections and global impacts, as well as implications for ENSO predictability. The 'Expert Guidance' section of this post summarizes the metrics used to characterize ENSO asymmetry and discusses the underlying physical mechanisms.</p> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--text-long.html.twig' --> </div> <!-- END OUTPUT from 'modules/composer/paragraphs/templates/paragraph.html.twig' --> </div> </div> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field.html.twig' --> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block--field-block--field-main-content.html.twig' --> <!-- THEME DEBUG --> <!-- THEME HOOK: 'block' --> <!-- FILE NAME SUGGESTIONS: * block--field-block--field-key-strengths.html.twig * block--field-block--node--climate-dataset--field-key-strengths.html.twig * block--field-block--node--climate-dataset.html.twig * block--field-block--node.html.twig * block--field-block.html.twig * block--layout-builder.html.twig x block.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> <div class="block block-layout-builder block-field-blocknodeclimate-datasetfield-key-strengths"> <h2 class="mb-md-2">Key Strengths</h2> <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--climate-dataset---custom--field-key-strengths.html.twig * field--node--field-key-strengths---custom.html.twig * field--node--climate-dataset--field-key-strengths.html.twig * field--node--field-key-strengths--climate-dataset--default.html.twig * field--node--field-key-strengths--climate-dataset.html.twig * field--node--field-key-strengths.html.twig * field--node--climate-dataset.html.twig * field--field-key-strengths.html.twig x field--text-long.html.twig * field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--text-long.html.twig' --> <div class="clearfix text-formatted field field--name-field-key-strengths field--type-text-long field--label-visually_hidden"> <div class="field__label visually-hidden">Key Strengths</div> <div class="field__items"> <div class="field__item"><p>A combination of metrics, including EOFs of SST anomalies, Niño SST indices, and rainfall skewness may be used to characterize the asymmetry and diversity of ENSO events</p> </div> <div class="field__item"><p>The mechanisms underlying ENSO asymmetry and diversity are becoming more well understood</p> </div> </div> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--text-long.html.twig' --> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> <!-- THEME DEBUG --> <!-- THEME HOOK: 'block' --> <!-- FILE NAME SUGGESTIONS: * block--field-block--field-key-limitations.html.twig * block--field-block--node--climate-dataset--field-key-limitations.html.twig * block--field-block--node--climate-dataset.html.twig * block--field-block--node.html.twig * block--field-block.html.twig * block--layout-builder.html.twig x block.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> <div class="block block-layout-builder block-field-blocknodeclimate-datasetfield-key-limitations"> <h2 class="mb-md-2">Key Limitations</h2> <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--climate-dataset---custom--field-key-limitations.html.twig * field--node--field-key-limitations---custom.html.twig * field--node--climate-dataset--field-key-limitations.html.twig * field--node--field-key-limitations--climate-dataset--default.html.twig * field--node--field-key-limitations--climate-dataset.html.twig * field--node--field-key-limitations.html.twig * field--node--climate-dataset.html.twig * field--field-key-limitations.html.twig x field--text-long.html.twig * field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--text-long.html.twig' --> <div class="clearfix text-formatted field field--name-field-key-limitations field--type-text-long field--label-visually_hidden"> <div class="field__label visually-hidden">Key Limitations</div> <div class="field__items"> <div class="field__item"><p>There lacks a simple, widely recognized diagnostic of ENSO asymmetry or diversity </p> </div> <div class="field__item"><p>Large-amplitude events can dominate ENSO composites or regression patterns</p> </div> </div> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--text-long.html.twig' --> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> <!-- THEME DEBUG --> <!-- THEME HOOK: 'block' --> <!-- FILE NAME SUGGESTIONS: * block--field-block--field-expert-user-guidance.html.twig * block--field-block--node--climate-dataset--field-expert-user-guidance.html.twig * block--field-block--node--climate-dataset.html.twig * block--field-block--node.html.twig * block--field-block.html.twig * block--layout-builder.html.twig x block.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> <div class="block block-layout-builder block-field-blocknodeclimate-datasetfield-expert-user-guidance"> <h2 class="mb-md-2">Expert User Guidance</h2> <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--climate-dataset---custom--field-expert-user-guidance.html.twig * field--node--field-expert-user-guidance---custom.html.twig * field--node--climate-dataset--field-expert-user-guidance.html.twig * field--node--field-expert-user-guidance--climate-dataset--default.html.twig * field--node--field-expert-user-guidance--climate-dataset.html.twig * field--node--field-expert-user-guidance.html.twig * field--node--climate-dataset.html.twig * field--field-expert-user-guidance.html.twig x field--text-long.html.twig * field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--text-long.html.twig' --> <div class="clearfix text-formatted field field--name-field-expert-user-guidance field--type-text-long field--label-visually_hidden"> <div class="field__label visually-hidden">Expert User Guidance</div> <div class="field__item"><p>The following was contributed by <strong>Dr. Agus Santoso</strong>, University of New South Wales, September, 2019:</p> <p>The El Niño Southern Oscillation (ENSO) is Earth’s strongest year-to-year climate variability with pronounced global impact.  There are to date several research articles, review papers and books covering the various aspects of ENSO, such as dynamics, teleconnection, impact, prediction, and future projections.  ENSO asymmetry and diversity have important implications on these societally relevant aspects.  This article provides a very brief overview of ENSO asymmetry and diversity, how we can diagnose them in nature, and how well they are represented in climate models. </p> <p>ENSO originates in the equatorial Pacific Ocean and vacillates irregularly every 2-7 years, switching between its positive phase (El Niño) and negative phase (La Niña).  El Niño and La Niña events are characterised by anomalous surface layer warming and cooling, respectively, over central to eastern equatorial Pacific Ocean that tend to peak toward the end of calendar year.  ENSO events develop through a suite of processes that take part in a positive air-sea feedback loop referred to as the Bjerknes feedback (Bjerknes 1969): e.g., surface warming induces anomalous westerly winds that deepen the thermocline (region of steepest vertical temperature gradient) thus reinforcing the initial surface warming, and the cycle continues.  The switch to an opposite phase generally involves propagation of oceanic waves that lead to a discharge or recharge of the upper equatorial Pacific heat content (also known as the ‘warm water volume’) priming the system for La Niña or El Niño respectively (Jin 1997; Meinen &amp; McPhaden 2000), with wind bursts often acting as a trigger (e.g., Chiodi &amp; Harrison 2015; Fedorov et al. 2015). </p> <p>Such anomalous warming and cooling occurring in the climatologically cool and dry region of the eastern Pacific (often referred to as the ‘cold tongue’ region) directly affect the Walker Circulation.  The Walker Circulation constitutes a low-level flow of air from the cold-tongue region towards the western Pacific warm pool (a vast area of warm water above 28°C surrounding the maritime continent) where air rises and upon reaching the upper troposphere it flows eastward and subsides over the cold tongue region.  The Walker Circulation weakens during El Niño and strengthens during La Niña.  During an El Niño, western and eastern Pacific receive less and more rainfall, respectively.  The converse occurs during a La Niña.  The impact of ENSO is also transmitted outside the tropical Pacific through atmospheric and oceanic waves, influencing climate variability sourced in other oceanic basins that can in turn affect ENSO (e.g., Cai et al. 2019).</p> <p>It is often generalized that La Niña is an opposite to El Niño.  While this holds true to a certain extent, El Niño and La Niña are not simply a mirror image of each other.  There is an apparent asymmetry in:</p> <p>1)     <em>pattern</em>: strong El Niño events tend to peak over eastern Pacific, while strong La Niña events tend to peak over central Pacific;</p> <p>2)     <em>amplitude</em>: El Niño can attain a notably larger magnitude than La Niña;</p> <p>3)     <em>duration</em>: El Niño events tend to be of shorter duration than La Niña events. </p> <p>The generalised ENSO sea surface temperature anomaly (SSTA) pattern is shown in Fig. 1a through regressing SSTA onto the Niño3.4 index (see contribution by Kevin Trenberth on Niño indices; <a href="https://climatedataguide.ucar.edu/climate-data/nino-sst-indices-nino-12-3-34-4-oni-and-tni" target="_blank">https://climatedataguide.ucar.edu/climate-data/Niño-sst-indices-Niño-12-3-34-4-oni-and-tni</a>).  The apparent asymmetry in SSTA pattern between the 1997-98 El Niño (Fig. 1b) and 1998-99 La Niña (Fig. 1c) demonstrates the laxity of this generalization.  The 1997-98 El Niño was dubbed “the climate event of the 20<sup>th</sup> Century”.  It was followed immediately by an extreme La Niña which lasted from 1998 to 2000.  This chain of events, i.e., a switch from an extreme El Niño to a back-to-back extreme La Niña, is a poster example of ENSO duration asymmetry (see Okumura &amp; Deser 2010 on this topic).  The key processes associated with 1997-2000 extreme ENSO events are captured in this animation: <a href="https://www.youtube.com/watch?v=gaFjlZxM7S4&amp;feature=youtu.be" target="_blank">https://www.youtube.com/watch?v=gaFjlZxM7S4&amp;feature=youtu.be</a>.</p> <p>Figure 2 shows SSTA in the equatorial Pacific from a different angle based on the NOAA ERSSTv5 reanalysis (Huang et al. 2017) from 1950-2018 as in Fig. 1.  The longitudinal profile during the peak ENSO season shows a cloud of SSTAs that is skewed eastward by the large positive SSTAs peaking in the Niño3 region. These SSTAs belong to the 1997-98 and 1982-83 El Niño events, the strongest El Niños in instrumental record, with the 1997-98 event being the most extreme.  The most recent extreme El Niño in 2015-16 peaks slightly to the west (more in the Niño3.4 region).  On the other hand, strong La Niña events (1973-74, 1975-76, 1988-1989, 1998-2000) peak about the central Pacific (Niño4 region).  Taking these strong ENSO events out of the picture, particularly the extreme El Niño ones, would make the longitudinal distribution of ENSO SSTAs more symmetrical.  Also apparent is that extreme El Niños attain notably stronger magnitude than extreme La Niñas.</p> <p>It is thus clear that ENSO asymmetry is shaped by the strong events, especially extreme El Niños.  The asymmetry in pattern and amplitude renders positive and negative skewness of SSTA in the Niño3 and Niño4 regions respectively, while in the Niño3.4 region the SSTA tends to be normally distributed (Burgers &amp; Stephenson 1999). </p> <p>The dominance of extreme events in ENSO asymmetry also skews the distribution of various metrics based on ocean and atmospheric variables in the tropical Pacific, such as surface wind velocities, rainfall, upper ocean heat content, direction of SSTA propagation, ocean currents, among others (see Santoso et al. 2017 for a review). These metrics can be used to define ENSO extremes and/or detect their potential emergence (e.g., see Fig. 24 of Santoso et al. 2017).  For example, a regularly updated daily time series of surface zonal wind velocity (e.g., NCEP/NCAR Reanalysis; Kalnay et al. 1996; accessible from <a href="http://www.esrl.noaa.gov/psd/" target="_blank">www.esrl.noaa.gov/psd/)</a> averaged over the central Pacific (5°S-5°N, 155°E-150°W) can be used to identify elevated activity of westerly wind bursts in boreal summer that would indicate potential emergence of an extreme El Niño at the end of the year.   On the other hand, the warm water volume or equivalently ocean temperature averaged above 300 m across the equatorial Pacific (5°S-5°N, 120°E-155°W; e.g., <a href="http://www.pmel.noaa.gov/tao/wwv/data/" target="_blank">www.pmel.noaa.gov/tao/wwv/data/</a>) in boreal spring indicates potential emergence of an extreme La Niña.  </p> <p>The variety of longitudinal distribution of the SSTA across the equatorial Pacific in Fig. 2 depicts that no ENSO events are exactly alike, thus the notion of ‘ENSO event diversity’.  In fact, diversity and asymmetry are two closely related dynamical aspects of ENSO.  The tendency for a strong El Niño to peak in the Eastern Pacific (EP), and a strong La Niña (and moderate El Niño) in the Central Pacific (CP) manifests from two dynamical EP and CP regimes that provide a continuum for events to occur with different ‘flavor’ (e.g., Capotondi et al. 2015; Takahashi &amp; Dewitte 2016; Timmermann et al. 2018).  Stochastic forcing, such as the westerly wind bursts, also contributes to ENSO diversity.  For instance, the presence of westerly wind bursts can lead to either a CP or EP El Niño depending if the initial heat content of the equatorial Pacific is normal or high, respectively (Fedorov et al. 2015).   </p> <p>Examining ENSO diversity can be done using EOF analysis of tropical Pacific SSTs (e.g., Takahashi et al. 2011; Dommenget et al. 2013), averaged over the peak ENSO season (e.g., December-February average).  The leading EOF depicts a typical ENSO SSTA pattern, while the second EOF depicts an opposing polarity between the central and eastern Pacific.  Superimposing EOF2 onto EOF1 results in a shift of the ENSO pattern.  Depending on the sign and intensity of the EOFs, the core SSTA shifts toward the east or central Pacific. The combination of the EOF principal component time series: E-index=(PC1+PC2)/sqrt(2); C-index=(PC1-PC2)/sqrt(2), represent the temporal evolution of EP and CP ENSO, respectively, which allows classifying ENSO events into EP or CP, or a mix of the two.  For example, the 1982-83 and 1997-98 events are considered as EP El Niño, while the 2015-16 event as a mix (see Fig. 1 of Santoso et al. 2019).  Should calculating EOFs prove to be cumbersome, PC1 and PC2 can be replaced with the Niño3 index and the Trans Niño Index (TNI), respectively, to yield a similar result (Santoso et al. 2017).  The TNI (Trenberth and Stephaniak 2001) is the difference between Niño1+2 and Niño4 (each with the mean removed and normalized).  There are also many invariants of EP and CP ENSO indices used in the literature as outlined by Capotondi et al. (2015). The EOF approach is recommended when analysing climate model output given the core location of the ENSO SST anomalies in climate models may not correspond well with the observed counterpart (Cai et al. 2018).  EOF analysis can also be used to examine ENSO diversity by applying it on longitude-time snapshots of several El Niño event samples (e.g., Lee et al. 2014).</p> <p>The observed quadratic relationship between PC1 and PC2 depicts the tendency for strong El Niño to peak in the eastern Pacific, and strong La Niña to peak in the central Pacific. The strength of curvature corresponds with the level of ENSO diversity.  If the curvature is weak, then the ENSO SSTA would tend to be more static, peaking in the Niño3.4 region. Thus, the parameter α in the following quadratic equation fitted to the data scatter on PC1-PC2 phase space is a measure of ENSO diversity: PC2=α*PC1<sup>2</sup>+β*PC1+γ (Dommenget et al. 2013; Karamperidou et al. 2017; Cai et al. 2018).     </p> <p>Atmosphere-ocean processes governing ENSO extremes that contribute to ENSO asymmetry and diversity are nonlinear (e.g., Kang &amp; Kug 2002; An &amp; Jin 2004; Choi et al. 2013; Dommenget et al. 2013; Cai et al. 2015; Takahashi &amp; Dewitte 2016; Timmermann et al. 2018; Cai et al. 2018). The climatological eastward sloping ocean thermocline, westward blowing trade winds, the warm pool in the west and the cold-tongue in the east, all of which are linked and sustain one another, provide the environment for nonlinear air-sea interactions to occur.  For instance, stronger reduction in atmospheric convection due to La Niña surface cooling occurs toward the warm pool (Hoerling et al. 1997).  This is because the cold tongue region is already dry, and thus further surface cooling exerts little effect, but stronger effect takes place in the central Pacific where there is more heat and humidity.  In contrast, shifts in atmospheric convection from the climatological convective zones (Intertropical Convergence Zone, the warm pool, South Pacific Convergence Zone) toward the cold tongue region need to be triggered by strong positive SSTA occurring in the region.  The outcropping climatological thermocline in the eastern equatorial Pacific allows vigorous air-sea interactions that favors generation of strong surface warming involving thermocline deepening.  Thus, another feature of ENSO asymmetry is the highly positive skewness in rainfall over the eastern equatorial Pacific associated with extreme El Niño.  As such, the Niño3 rainfall time series can be used to identify extreme El Niño events in observations and models (e.g., Cai et al. 2014 using December-February average Niño3 rainfall &gt; 5 mm/day).  Synoptic scale processes also contribute to ENSO asymmetry.  For instance, tropical instability waves that exert a damping on ENSO SST anomalies are more active during La Niña than El Niño (An 2008).</p> <p>Climate models can simulate a diverse range of ENSO events to various extent, with some more realistic than others (e.g., Kim &amp; Yu 2012; Taschetto et al. 2014).  However, they overall underestimate the degree of the observed ENSO asymmetry and diversity (e.g., Ham &amp; Kug 2012; Dommenget et al. 2013; Zhang &amp; Sun 2014; Sun et al. 2016; Karamperidou et al. 2017; Cai et al. 2018).  This is evident in the weaker skewness of the Niño indices compared to the observed counterpart (Fig. 4). The curvature of the PC1-PC2 relationship described above also tends to be underestimated, as reflected in the overall weaker than observed α parameter (Fig. 5).  The underestimation of ENSO asymmetry and diversity is linked to systematic biases associated with model deficiency in capturing crucial physical processes such as atmospheric convection, cloud formation, and other subgrid-scale processes.  For instance, the persistent cold tongue bias (cooler than observed eastern-central equatorial Pacific) tend to confine atmospheric convection in the warm pool areas, making it more difficult to shift convection toward the eastern equatorial Pacific (Ham &amp; Kug 2012; Sun et al. 2016), a crucial process of extreme El Niños.  In association, many models also underestimate the positive skewness of Niño3 rainfall (Cai et al. 2014).  The farther west location and the narrower meridional structure of the modeled ENSO wind anomalies than observed contribute to overly regular ENSO oscillation (Capotondi et al. 2006), thus a weaker duration asymmetry (Choi et al. 2013).  In addition, the coarse resolution of the ocean and atmospheric sub-model components also makes it challenging to resolve small-scale processes that contribute in shaping ENSO asymmetry and diversity, such as the tropical instability waves and Madden Julian Oscillation which contributes to westerly wind bursts (e.g., Graham 2014; Feng &amp; Lian 2018). ##</p> <div> </div> </div> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--text-long.html.twig' --> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> </main> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/layout/layout--twocol-section.html.twig' --> Mon, 20 Jan 2020 16:49:00 +0000 ryanj 1167 at https://climatedataguide.ucar.edu Tropical Moored Buoy System: TAO, TRITON, PIRATA, RAMA (TOGA) https://climatedataguide.ucar.edu/climate-data/tropical-moored-buoy-system-tao-triton-pirata-rama-toga <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--climate-dataset--rss--title.html.twig * field--node--title--rss.html.twig * field--node--climate-dataset--title.html.twig * field--node--title--climate-dataset.html.twig x field--node--title.html.twig * field--node--climate-dataset.html.twig * field--title.html.twig * field--string.html.twig * field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--node--title.html.twig' --> <span class="field field--name-title field--type-string field--label-hidden">Tropical Moored Buoy System: TAO, TRITON, PIRATA, RAMA (TOGA)</span> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--node--title.html.twig' --> <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--climate-dataset--rss--uid.html.twig * field--node--uid--rss.html.twig * field--node--climate-dataset--uid.html.twig * field--node--uid--climate-dataset.html.twig x field--node--uid.html.twig * field--node--climate-dataset.html.twig * field--uid.html.twig * field--entity-reference.html.twig * field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--node--uid.html.twig' --> <span class="field field--name-uid field--type-entity-reference field--label-hidden"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'username' --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/user/username.html.twig' --> <span lang="" about="/user/2" typeof="schema:Person" property="schema:name" datatype="">ryanj</span> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/user/username.html.twig' --> </span> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--node--uid.html.twig' --> <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--climate-dataset--rss--created.html.twig * field--node--created--rss.html.twig * field--node--climate-dataset--created.html.twig * field--node--created--climate-dataset.html.twig x field--node--created.html.twig * field--node--climate-dataset.html.twig * field--created.html.twig * field--created.html.twig * field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--node--created.html.twig' --> <span class="field field--name-created field--type-created field--label-hidden">Tue, 04/09/2013 - 05:27</span> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--node--created.html.twig' --> <!-- THEME DEBUG --> <!-- THEME HOOK: 'layout__twocol_section' --> <!-- FILE NAME SUGGESTIONS: x layout--twocol-section.html.twig x layout--twocol-section.html.twig * layout.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/layout/layout--twocol-section.html.twig' --> <div> <div class="layout__region layout__region--main-top breadcrumb-wrapper mt-2"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'block' --> <!-- FILE NAME SUGGESTIONS: * block--system-breadcrumb-block.html.twig * block--system.html.twig x block.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> <div class="block block-system block-system-breadcrumb-block"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'breadcrumb' --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/navigation/breadcrumb.html.twig' --> <nav class="mb-2 d-print-none" role="navigation" aria-labelledby="system-breadcrumb"> <h2 id="system-breadcrumb" class="visually-hidden">Breadcrumb</h2> <ol class="breadcrumb"> <li class="breadcrumb-item"> <a href="/">Home</a> </li> <li class="breadcrumb-item"> <a href="/domains/tropics">Tropics</a> </li> </ol> </nav> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/navigation/breadcrumb.html.twig' --> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> </div> <main class="layout__region layout__region--main main-content-wrapper"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'block' --> <!-- FILE NAME SUGGESTIONS: * block--field-block--field-primary-image.html.twig * block--field-block--node--climate-dataset--field-primary-image.html.twig * block--field-block--node--climate-dataset.html.twig * block--field-block--node.html.twig * block--field-block.html.twig * block--layout-builder.html.twig x block.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> <div class="block block-layout-builder block-field-blocknodeclimate-datasetfield-primary-image"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--climate-dataset---custom--field-primary-image.html.twig * field--node--field-primary-image---custom.html.twig * field--node--climate-dataset--field-primary-image.html.twig * field--node--field-primary-image--climate-dataset--default.html.twig * field--node--field-primary-image--climate-dataset.html.twig * field--node--field-primary-image.html.twig * field--node--climate-dataset.html.twig * field--field-primary-image.html.twig * field--entity-reference.html.twig x field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field.html.twig' --> <div class="field field--name-field-primary-image field--type-entity-reference field--label-visually_hidden"> <div class="field__label visually-hidden">Teaser image</div> <div class="field__item"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'image_formatter' --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/image-formatter.html.twig' --> <!-- THEME DEBUG --> <!-- THEME HOOK: 'image' --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/image.html.twig' --> <img src="/sites/default/files/2022-03/teaser_images_556.png" width="1400" height="490" alt="Tropical Moored Buoy System: TAO, TRITON, PIRATA, RAMA (TOGA)" loading="lazy" typeof="foaf:Image" class="img-fluid" /> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/image.html.twig' --> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/image-formatter.html.twig' --> </div> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field.html.twig' --> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> <!-- THEME DEBUG --> <!-- THEME HOOK: 'block' --> <!-- FILE NAME SUGGESTIONS: x block--field-block--field-main-content.html.twig * block--field-block--node--climate-dataset--field-main-content.html.twig * block--field-block--node--climate-dataset.html.twig * block--field-block--node.html.twig * block--field-block.html.twig * block--layout-builder.html.twig * block.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block--field-block--field-main-content.html.twig' --> <div class="mt-3 mt-md-4 block block-layout-builder block-field-blocknodeclimate-datasetfield-main-content"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--climate-dataset---custom--field-main-content.html.twig * field--node--field-main-content---custom.html.twig * field--node--climate-dataset--field-main-content.html.twig * field--node--field-main-content--climate-dataset--default.html.twig * field--node--field-main-content--climate-dataset.html.twig * field--node--field-main-content.html.twig * field--node--climate-dataset.html.twig * field--field-main-content.html.twig * field--entity-reference-revisions.html.twig x field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field.html.twig' --> <div class="field field--name-field-main-content field--type-entity-reference-revisions field--label-visually_hidden"> <div class="field__label visually-hidden">Main content</div> <div class="field__items"> <div class="field__item"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'paragraph' --> <!-- FILE NAME SUGGESTIONS: * paragraph--climate-dataset--rich-text.html.twig * paragraph--rich-text--.html.twig * paragraph--rich-text--default.html.twig * paragraph--rich-text.html.twig * paragraph--default.html.twig x paragraph.html.twig --> <!-- BEGIN OUTPUT from 'modules/composer/paragraphs/templates/paragraph.html.twig' --> <div class="paragraph paragraph--type--rich-text paragraph--view-mode--default"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--paragraph--field-body--default--climate-dataset.html.twig * field--rich-text--default--field-body.html.twig * field--paragraph--field-body--default.html.twig * field--paragraph--rich-text--field-body.html.twig * field--paragraph--field-body--rich-text.html.twig * field--paragraph--field-body.html.twig * field--paragraph--rich-text.html.twig * field--field-body.html.twig x field--text-long.html.twig * field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--text-long.html.twig' --> <div class="clearfix text-formatted field field--name-field-body field--type-text-long field--label-hidden field__item"><p>The Tropical Ocean Global Atmosphere program (TOGA) is a component of the World Climate Research Programme (WCRP) aimed specifically at the prediction of climate phenomena on time scales of months to years. In order to achieve the TOGA goals, a strategy of large-scale, long-term monitoring of the upper ocean and the atmosphere has been developed. In particular, several moored bouy projects have been developed. <span class="style30">The Global Tropical Moored Buoy Array is a multi-national effort to provide data in real-time for climate research and forecasting. Major components include the <a href="http://www.pmel.noaa.gov/tao/">TAO/TRITON</a> array in the Pacific, <a href="http://www.pmel.noaa.gov/pirata/">PIRATA</a> in the Atlantic, and <a href="http://www.pmel.noaa.gov/tao/rama/">RAMA</a> in the Indian Ocean. </span> The TAO array (renamed the TAO/TRITON array on 1 January 2000) consists of approximately 70 moorings in the Tropical Pacific Ocean; PIRATA use ~20 bouys; and, RAMA uses ~23 bouys.</p> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--text-long.html.twig' --> </div> <!-- END OUTPUT from 'modules/composer/paragraphs/templates/paragraph.html.twig' --> </div> </div> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field.html.twig' --> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block--field-block--field-main-content.html.twig' --> </main> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/layout/layout--twocol-section.html.twig' --> Tue, 09 Apr 2013 11:27:00 +0000 ryanj 918 at https://climatedataguide.ucar.edu QBO: Quasi-Biennial Oscillation https://climatedataguide.ucar.edu/climate-data/qbo-quasi-biennial-oscillation <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--climate-dataset--rss--title.html.twig * field--node--title--rss.html.twig * field--node--climate-dataset--title.html.twig * field--node--title--climate-dataset.html.twig x field--node--title.html.twig * field--node--climate-dataset.html.twig * field--title.html.twig * field--string.html.twig * field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--node--title.html.twig' --> <span class="field field--name-title field--type-string field--label-hidden">QBO: Quasi-Biennial Oscillation</span> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--node--title.html.twig' --> <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--climate-dataset--rss--uid.html.twig * field--node--uid--rss.html.twig * field--node--climate-dataset--uid.html.twig * field--node--uid--climate-dataset.html.twig x field--node--uid.html.twig * field--node--climate-dataset.html.twig * field--uid.html.twig * field--entity-reference.html.twig * field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--node--uid.html.twig' --> <span class="field field--name-uid field--type-entity-reference field--label-hidden"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'username' --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/user/username.html.twig' --> <span lang="" about="/user/2" typeof="schema:Person" property="schema:name" datatype="">ryanj</span> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/user/username.html.twig' --> </span> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--node--uid.html.twig' --> <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--climate-dataset--rss--created.html.twig * field--node--created--rss.html.twig * field--node--climate-dataset--created.html.twig * field--node--created--climate-dataset.html.twig x field--node--created.html.twig * field--node--climate-dataset.html.twig * field--created.html.twig * field--created.html.twig * field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--node--created.html.twig' --> <span class="field field--name-created field--type-created field--label-hidden">Mon, 04/16/2012 - 11:37</span> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--node--created.html.twig' --> <!-- THEME DEBUG --> <!-- THEME HOOK: 'layout__twocol_section' --> <!-- FILE NAME SUGGESTIONS: x layout--twocol-section.html.twig x layout--twocol-section.html.twig * layout.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/layout/layout--twocol-section.html.twig' --> <div> <div class="layout__region layout__region--main-top breadcrumb-wrapper mt-2"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'block' --> <!-- FILE NAME SUGGESTIONS: * block--system-breadcrumb-block.html.twig * block--system.html.twig x block.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> <div class="block block-system block-system-breadcrumb-block"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'breadcrumb' --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/navigation/breadcrumb.html.twig' --> <nav class="mb-2 d-print-none" role="navigation" aria-labelledby="system-breadcrumb"> <h2 id="system-breadcrumb" class="visually-hidden">Breadcrumb</h2> <ol class="breadcrumb"> <li class="breadcrumb-item"> <a href="/">Home</a> </li> <li class="breadcrumb-item"> <a href="/domains/tropics">Tropics</a> </li> </ol> </nav> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/navigation/breadcrumb.html.twig' --> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> </div> <main class="layout__region layout__region--main main-content-wrapper"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'block' --> <!-- FILE NAME SUGGESTIONS: * block--field-block--field-primary-image.html.twig * block--field-block--node--climate-dataset--field-primary-image.html.twig * block--field-block--node--climate-dataset.html.twig * block--field-block--node.html.twig * block--field-block.html.twig * block--layout-builder.html.twig x block.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> <div class="block block-layout-builder block-field-blocknodeclimate-datasetfield-primary-image"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--climate-dataset---custom--field-primary-image.html.twig * field--node--field-primary-image---custom.html.twig * field--node--climate-dataset--field-primary-image.html.twig * field--node--field-primary-image--climate-dataset--default.html.twig * field--node--field-primary-image--climate-dataset.html.twig * field--node--field-primary-image.html.twig * field--node--climate-dataset.html.twig * field--field-primary-image.html.twig * field--entity-reference.html.twig x field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field.html.twig' --> <div class="field field--name-field-primary-image field--type-entity-reference field--label-visually_hidden"> <div class="field__label visually-hidden">Teaser image</div> <div class="field__item"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'image_formatter' --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/image-formatter.html.twig' --> <!-- THEME DEBUG --> <!-- THEME HOOK: 'image' --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/image.html.twig' --> <img src="/sites/default/files/2022-03/teaser_images_614.png" width="942" height="478" alt="QBO: Quasi-Biennial Oscillation" loading="lazy" typeof="foaf:Image" class="img-fluid" /> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/image.html.twig' --> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/image-formatter.html.twig' --> </div> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field.html.twig' --> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> <!-- THEME DEBUG --> <!-- THEME HOOK: 'block' --> <!-- FILE NAME SUGGESTIONS: x block--field-block--field-main-content.html.twig * block--field-block--node--climate-dataset--field-main-content.html.twig * block--field-block--node--climate-dataset.html.twig * block--field-block--node.html.twig * block--field-block.html.twig * block--layout-builder.html.twig * block.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block--field-block--field-main-content.html.twig' --> <div class="mt-3 mt-md-4 block block-layout-builder block-field-blocknodeclimate-datasetfield-main-content"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--climate-dataset---custom--field-main-content.html.twig * field--node--field-main-content---custom.html.twig * field--node--climate-dataset--field-main-content.html.twig * field--node--field-main-content--climate-dataset--default.html.twig * field--node--field-main-content--climate-dataset.html.twig * field--node--field-main-content.html.twig * field--node--climate-dataset.html.twig * field--field-main-content.html.twig * field--entity-reference-revisions.html.twig x field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field.html.twig' --> <div class="field field--name-field-main-content field--type-entity-reference-revisions field--label-visually_hidden"> <div class="field__label visually-hidden">Main content</div> <div class="field__items"> <div class="field__item"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'paragraph' --> <!-- FILE NAME SUGGESTIONS: * paragraph--climate-dataset--rich-text.html.twig * paragraph--rich-text--.html.twig * paragraph--rich-text--default.html.twig * paragraph--rich-text.html.twig * paragraph--default.html.twig x paragraph.html.twig --> <!-- BEGIN OUTPUT from 'modules/composer/paragraphs/templates/paragraph.html.twig' --> <div class="paragraph paragraph--type--rich-text paragraph--view-mode--default"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--paragraph--field-body--default--climate-dataset.html.twig * field--rich-text--default--field-body.html.twig * field--paragraph--field-body--default.html.twig * field--paragraph--rich-text--field-body.html.twig * field--paragraph--field-body--rich-text.html.twig * field--paragraph--field-body.html.twig * field--paragraph--rich-text.html.twig * field--field-body.html.twig x field--text-long.html.twig * field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--text-long.html.twig' --> <div class="clearfix text-formatted field field--name-field-body field--type-text-long field--label-hidden field__item"><p>The quasi-biennial oscillation (QBO) is a quasi-periodic oscillation of the equatorial zonal wind between easterlies and westerlies in the tropical stratosphere with a mean period of 28 to 29 months. The alternating wind regimes develop at the top of the lower stratosphere and propagate downwards at about 1 km (0.6 mi) per month until they are dissipated at the tropical tropopause. Downward motion of the easterlies is usually more irregular than that of the westerlies. The amplitude of the easterly phase is about twice as strong as that of the westerly phase. At the top of the vertical QBO domain, easterlies dominate, while at the bottom, westerlies are more likely to be found. (Wikipedia)</p> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--text-long.html.twig' --> </div> <!-- END OUTPUT from 'modules/composer/paragraphs/templates/paragraph.html.twig' --> </div> </div> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field.html.twig' --> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block--field-block--field-main-content.html.twig' --> </main> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/layout/layout--twocol-section.html.twig' --> Mon, 16 Apr 2012 17:37:00 +0000 ryanj 785 at https://climatedataguide.ucar.edu TRMM: Tropical Rainfall Measuring Mission https://climatedataguide.ucar.edu/climate-data/trmm-tropical-rainfall-measuring-mission <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--climate-dataset--rss--title.html.twig * field--node--title--rss.html.twig * field--node--climate-dataset--title.html.twig * field--node--title--climate-dataset.html.twig x field--node--title.html.twig * field--node--climate-dataset.html.twig * field--title.html.twig * field--string.html.twig * field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--node--title.html.twig' --> <span class="field field--name-title field--type-string field--label-hidden">TRMM: Tropical Rainfall Measuring Mission</span> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--node--title.html.twig' --> <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--climate-dataset--rss--uid.html.twig * field--node--uid--rss.html.twig * field--node--climate-dataset--uid.html.twig * field--node--uid--climate-dataset.html.twig x field--node--uid.html.twig * field--node--climate-dataset.html.twig * field--uid.html.twig * field--entity-reference.html.twig * field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--node--uid.html.twig' --> <span class="field field--name-uid field--type-entity-reference field--label-hidden"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'username' --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/user/username.html.twig' --> <span lang="" about="/user/2" typeof="schema:Person" property="schema:name" datatype="">ryanj</span> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/user/username.html.twig' --> </span> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--node--uid.html.twig' --> <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--climate-dataset--rss--created.html.twig * field--node--created--rss.html.twig * field--node--climate-dataset--created.html.twig * field--node--created--climate-dataset.html.twig x field--node--created.html.twig * field--node--climate-dataset.html.twig * field--created.html.twig * field--created.html.twig * field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--node--created.html.twig' --> <span class="field field--name-created field--type-created field--label-hidden">Tue, 11/15/2011 - 07:37</span> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--node--created.html.twig' --> <!-- THEME DEBUG --> <!-- THEME HOOK: 'layout__twocol_section' --> <!-- FILE NAME SUGGESTIONS: x layout--twocol-section.html.twig x layout--twocol-section.html.twig * layout.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/layout/layout--twocol-section.html.twig' --> <div> <div class="layout__region layout__region--main-top breadcrumb-wrapper mt-2"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'block' --> <!-- FILE NAME SUGGESTIONS: * block--system-breadcrumb-block.html.twig * block--system.html.twig x block.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> <div class="block block-system block-system-breadcrumb-block"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'breadcrumb' --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/navigation/breadcrumb.html.twig' --> <nav class="mb-2 d-print-none" role="navigation" aria-labelledby="system-breadcrumb"> <h2 id="system-breadcrumb" class="visually-hidden">Breadcrumb</h2> <ol class="breadcrumb"> <li class="breadcrumb-item"> <a href="/">Home</a> </li> <li class="breadcrumb-item"> <a href="/domains/tropics">Tropics</a> </li> </ol> </nav> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/navigation/breadcrumb.html.twig' --> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> </div> <main class="layout__region layout__region--main main-content-wrapper"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'block' --> <!-- FILE NAME SUGGESTIONS: * block--field-block--field-primary-image.html.twig * block--field-block--node--climate-dataset--field-primary-image.html.twig * block--field-block--node--climate-dataset.html.twig * block--field-block--node.html.twig * block--field-block.html.twig * block--layout-builder.html.twig x block.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> <div class="block block-layout-builder block-field-blocknodeclimate-datasetfield-primary-image"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--climate-dataset---custom--field-primary-image.html.twig * field--node--field-primary-image---custom.html.twig * field--node--climate-dataset--field-primary-image.html.twig * field--node--field-primary-image--climate-dataset--default.html.twig * field--node--field-primary-image--climate-dataset.html.twig * field--node--field-primary-image.html.twig * field--node--climate-dataset.html.twig * field--field-primary-image.html.twig * field--entity-reference.html.twig x field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field.html.twig' --> <div class="field field--name-field-primary-image field--type-entity-reference field--label-visually_hidden"> <div class="field__label visually-hidden">Teaser image</div> <div class="field__item"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'image_formatter' --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/image-formatter.html.twig' --> <!-- THEME DEBUG --> <!-- THEME HOOK: 'image' --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/image.html.twig' --> <img src="/sites/default/files/2022-03/TRMM_CLM.V7_July_0.png" width="673" height="269" alt="TRMM: Tropical Rainfall Measuring Mission" loading="lazy" typeof="foaf:Image" class="img-fluid" /> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/image.html.twig' --> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/image-formatter.html.twig' --> </div> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field.html.twig' --> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> <!-- THEME DEBUG --> <!-- THEME HOOK: 'block' --> <!-- FILE NAME SUGGESTIONS: x block--field-block--field-main-content.html.twig * block--field-block--node--climate-dataset--field-main-content.html.twig * block--field-block--node--climate-dataset.html.twig * block--field-block--node.html.twig * block--field-block.html.twig * block--layout-builder.html.twig * block.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block--field-block--field-main-content.html.twig' --> <div class="mt-3 mt-md-4 block block-layout-builder block-field-blocknodeclimate-datasetfield-main-content"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--climate-dataset---custom--field-main-content.html.twig * field--node--field-main-content---custom.html.twig * field--node--climate-dataset--field-main-content.html.twig * field--node--field-main-content--climate-dataset--default.html.twig * field--node--field-main-content--climate-dataset.html.twig * field--node--field-main-content.html.twig * field--node--climate-dataset.html.twig * field--field-main-content.html.twig * field--entity-reference-revisions.html.twig x field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field.html.twig' --> <div class="field field--name-field-main-content field--type-entity-reference-revisions field--label-visually_hidden"> <div class="field__label visually-hidden">Main content</div> <div class="field__items"> <div class="field__item"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'paragraph' --> <!-- FILE NAME SUGGESTIONS: * paragraph--climate-dataset--rich-text.html.twig * paragraph--rich-text--.html.twig * paragraph--rich-text--default.html.twig * paragraph--rich-text.html.twig * paragraph--default.html.twig x paragraph.html.twig --> <!-- BEGIN OUTPUT from 'modules/composer/paragraphs/templates/paragraph.html.twig' --> <div class="paragraph paragraph--type--rich-text paragraph--view-mode--default"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--paragraph--field-body--default--climate-dataset.html.twig * field--rich-text--default--field-body.html.twig * field--paragraph--field-body--default.html.twig * field--paragraph--rich-text--field-body.html.twig * field--paragraph--field-body--rich-text.html.twig * field--paragraph--field-body.html.twig * field--paragraph--rich-text.html.twig * field--field-body.html.twig x field--text-long.html.twig * field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--text-long.html.twig' --> <div class="clearfix text-formatted field field--name-field-body field--type-text-long field--label-hidden field__item"><p>The Tropical Rainfall Measuring Mission (TRMM) is a joint space mission between NASA and Japan's National Space Development Agency designed to monitor and study tropical and subtropical precipitation and the associated release of energy. The mission uses 5 instruments: Precipitation Radar (PR), TRMM Microwave Imager (TMI), Visible Infrared Scanner (VIRS), Clouds &amp; Earths Radiant Energy System (CERES) and  Lightning Imaging Sensor (LSI).  The TMI and PR are the main instruments used for precipitation.  These instruments are used in an algorithm that forms the TRMM Combined Instrument (TCI) calibration data set (TRMM 2B31) for the TRMM Multi-satellite Precipitation Analysis (TMPA), whose TMPA 3B43 monthly precipitation averages and TMPA 3B42 daily and sub-daily (3hr) averages are probably the most relevant TRMM-related products for climate research. 3B42 and 3B43 are available in 0.25° spatial resolution, covering 50°N to 50°S for 1998-present.</p> <p>As discussed in the <a href="https://climatedataguide.ucar.edu/climate-data/trmm-tropical-rainfall-measuring-mission?qt-climatedatasetmaintabs=1#qt-climatedatasetmaintabs">Expert Guidance</a>, the TMPA combines microwave data from multiple satellites including SSMI, SSMIS, MHS, AMSU-B and AMSR-E, each inter-calibrated to the TCI.   Coverage gaps in space and time are filled in with calibrated infrared (IR) data (which are generally available with near-global coverage every 3 hours); coefficients are derived from co-located IR brightness temperatures and the microwave-based precipitation estimates. The final data products reflect scaling the multi-satellite estimates to rain gauge data on a monthly basis, and ensuring that the 3-hourly averages in 3B42 sum to the monthly totals in 3B43.  </p> <p>Due to the fact that TMPA timeseries are bulit up with estimates from  constantly varying data sources, it is likely that inhomegeneities in the temporal record exist.  Each precipitation field should be interpreted as the best estimate of precipitation in each grid point at the observation time.  In general, as a high-resolution precipitation product, TMPA does not have the same homogeneity goals as a climate dataset like GPCP v2.2.  Indeed, significant discrepancies in the interannual variability of rainfall over the ocean have been reported between TMPA  version 7 and GPCP v2.2; see the Figures below for illustration.  </p> <p>After 17 years (1997-4/2015)  the <a href="http://pmm.nasa.gov/trmm/mission-end" target="_blank">TRMM mission came to an end</a>. The Global Precipitation Mission (GPM) is the successor mission. New products to supersede the TMPA datasets are being produced under the Global Precipitation Measurement (GPM) umbrella with the Integrated Multi-satellitE Retrievals for GPM (IMERG) algorithm. TRMM-era data have been reprocessed using the IMERG algorithm for 2000-present, creating a long-term continuous record. Likewise, the TMPA 3B42 and 3B43 analyses have continued into the GPM era, but are slated to end production at the end of 2019.</p> <p class="lexicon-term"> </p> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--text-long.html.twig' --> </div> <!-- END OUTPUT from 'modules/composer/paragraphs/templates/paragraph.html.twig' --> </div> </div> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field.html.twig' --> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block--field-block--field-main-content.html.twig' --> <!-- THEME DEBUG --> <!-- THEME HOOK: 'block' --> <!-- FILE NAME SUGGESTIONS: * block--field-block--field-key-strengths.html.twig * block--field-block--node--climate-dataset--field-key-strengths.html.twig * block--field-block--node--climate-dataset.html.twig * block--field-block--node.html.twig * block--field-block.html.twig * block--layout-builder.html.twig x block.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> <div class="block block-layout-builder block-field-blocknodeclimate-datasetfield-key-strengths"> <h2 class="mb-md-2">Key Strengths</h2> <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--climate-dataset---custom--field-key-strengths.html.twig * field--node--field-key-strengths---custom.html.twig * field--node--climate-dataset--field-key-strengths.html.twig * field--node--field-key-strengths--climate-dataset--default.html.twig * field--node--field-key-strengths--climate-dataset.html.twig * field--node--field-key-strengths.html.twig * field--node--climate-dataset.html.twig * field--field-key-strengths.html.twig x field--text-long.html.twig * field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--text-long.html.twig' --> <div class="clearfix text-formatted field field--name-field-key-strengths field--type-text-long field--label-visually_hidden"> <div class="field__label visually-hidden">Key Strengths</div> <div class="field__items"> <div class="field__item"><p>Uniquely offers high spatial and temporal resolution precipitation estimates over a relatively long period of record (since 1998)</p> </div> <div class="field__item"><p>Useful for investigating the climatological distribution of rainfall, and its frequency and intensity</p> </div> <div class="field__item"><p>Useful for validation of tropical precipitation in climate models, provided that care is taken to put the data on comparable grids using conservative regridding and to use accumulated (rather than instantaneous) precipitation</p> </div> </div> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--text-long.html.twig' --> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> <!-- THEME DEBUG --> <!-- THEME HOOK: 'block' --> <!-- FILE NAME SUGGESTIONS: * block--field-block--field-key-limitations.html.twig * block--field-block--node--climate-dataset--field-key-limitations.html.twig * block--field-block--node--climate-dataset.html.twig * block--field-block--node.html.twig * block--field-block.html.twig * block--layout-builder.html.twig x block.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> <div class="block block-layout-builder block-field-blocknodeclimate-datasetfield-key-limitations"> <h2 class="mb-md-2">Key Limitations</h2> <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--climate-dataset---custom--field-key-limitations.html.twig * field--node--field-key-limitations---custom.html.twig * field--node--climate-dataset--field-key-limitations.html.twig * field--node--field-key-limitations--climate-dataset--default.html.twig * field--node--field-key-limitations--climate-dataset.html.twig * field--node--field-key-limitations.html.twig * field--node--climate-dataset.html.twig * field--field-key-limitations.html.twig x field--text-long.html.twig * field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--text-long.html.twig' --> <div class="clearfix text-formatted field field--name-field-key-limitations field--type-text-long field--label-visually_hidden"> <div class="field__label visually-hidden">Key Limitations</div> <div class="field__items"> <div class="field__item"><p>Complex algorithms are required to translate indirect and infrequent satellite measurements into high-resolution gridded precipitation estimates at regular time intervals</p> </div> <div class="field__item"><p>TRMM precipitation radar algorithm likely underestimates precipitation in (a) regions of intense convection over land and (b) higher latitudes</p> </div> <div class="field__item"><p>As a Climate Data Record with global coverage, GPCP should be preferred over TRMM for large-scale climate variability studies</p> </div> </div> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--text-long.html.twig' --> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> <!-- THEME DEBUG --> <!-- THEME HOOK: 'block' --> <!-- FILE NAME SUGGESTIONS: * block--field-block--field-expert-user-guidance.html.twig * block--field-block--node--climate-dataset--field-expert-user-guidance.html.twig * block--field-block--node--climate-dataset.html.twig * block--field-block--node.html.twig * block--field-block.html.twig * block--layout-builder.html.twig x block.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> <div class="block block-layout-builder block-field-blocknodeclimate-datasetfield-expert-user-guidance"> <h2 class="mb-md-2">Expert User Guidance</h2> <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--climate-dataset---custom--field-expert-user-guidance.html.twig * field--node--field-expert-user-guidance---custom.html.twig * field--node--climate-dataset--field-expert-user-guidance.html.twig * field--node--field-expert-user-guidance--climate-dataset--default.html.twig * field--node--field-expert-user-guidance--climate-dataset.html.twig * field--node--field-expert-user-guidance.html.twig * field--node--climate-dataset.html.twig * field--field-expert-user-guidance.html.twig x field--text-long.html.twig * field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--text-long.html.twig' --> <div class="clearfix text-formatted field field--name-field-expert-user-guidance field--type-text-long field--label-visually_hidden"> <div class="field__label visually-hidden">Expert User Guidance</div> <div class="field__item"><p class="Body">The following was contributed by Dr. Angeline Pendergrass (NCAR), July, 2014:</p> <p class="Body"><strong>"TRMM 3B42 3-h precipitation data</strong></p> <p class="Body"> TRMM 3B42 is a high-resolution (in both time and space) gridded record of precipitation. It provides rain rate in mm/hr with a spatial resolution of 0.25 degrees in latitude and longitude, with coverage from 50 S to 50 N, every 3 hours starting 1 January 1998 (when TRMM data became available) through a few months before present (with a lag for data processing).  The rain rates are not instantaneous, but rather add up to monthly rainfall estimates found in TRMM 3B43.  The product is at version 7 at the time of writing.</p> <p class="Body">The measurements that go into the TRMM 3B42 precipitation estimates are from the TRMM passive microwave radiometer and precipitation radar, infrared radiometers, infrared brightness temperatures from geostationary satellites, and rain gauge measurements in a final step.  The TRMM data are used to make monthly IR calibration tables, which are applied to the IR geostationary data to obtain the 3-hourly data, and then rescaled to agree with co-located microwave measurements and monthly rain gauge observations.</p> <p class="Body">Typical research applications of this dataset include examining the climatological distribution of rainfall, and its frequency and intensity (e.g., Dai et al 2007, Biasutti and Yuter 2013, Pendergrass 2013), precipitation extremes (e.g., Rossow et al 2013), and properties of precipitating systems (e.g., Roca et al 2014).  It can be used for validation of the distribution of tropical rain in climate models (e.g., Lin et al 2013, Donner et al 2011).  Because of its high temporal resolution, the dataset can be used to explore the diurnal cycle (e.g., Chen et al 2012). </p> <p class="Body"> The key limitation of this dataset (like all merged-satellite precipitation products) is the indirect and complex nature of translating sparse satellite precipitation measurements into high-resolution gridded precipitation estimates.  Satellites can only indirectly measure quantities related to rain rate at the surface: microwave and infrared satellites measure brightness temperature, which is then converted to rain rate indirectly, while radars measure energy reflected by cloud and rain drops throughout the depth of the column.  Then, these indirect measurements (along with direct gauge measurements over land) are used as an input to a complex algorithm that produces estimates of surface rain rate on a regular grid in time and space. Finally, the satellite data used in TRMM misses many light rain events (Behrangi et al 2012, 2014).</p> <p class="Body">To quantify the uncertainty of the rainfall estimates in TRMM3B42, the relative error in mm/hr is available for each datapoint in time and space. See Huffman (1997) for a complete description.   However, these methods cannot account for the structural uncertainty in measuring precipitation, especially over the ocean where there is very limited opportunity for ground validation.</p> <p class="Body">The TRMM 3B42 data are available in binary format via ftp.  The MIRADOR web-based interface can convert the data to NetCDF (<a href="http://mirador.gsfc.nasa.gov/cgi-bin/mirador/presentNavigation.pl?tree=project&amp;project=TRMM">http://mirador.gsfc.nasa.gov/cgi-bin/mirador/presentNavigation.pl?tree=project&amp;project=TRMM</a>). The TOVAS web-based interface can plot the data as well as prepare data files for download in NetCDF and HDF formats (<a href="http://gdata1.sci.gsfc.nasa.gov/daac-bin/G3/gui.cgi?instance_id=TRMM_3B42_Daily">http://gdata1.sci.gsfc.nasa.gov/daac-bin/G3/gui.cgi?instance_id=TRMM_3B42_Daily</a>).  The data are also available in HDF format via ftp at <a href="ftp://trmmopen.gsfc.nasa.gov/pub/TMPA/TRMMstandard/3B42/">ftp://trmmopen.gsfc.nasa.gov/pub/TMPA/TRMMstandard/3B42/</a>.</p> <p class="Body"> Precipitation rate depends strongly on resolution in time and space, which is the source of the most common errors processing and interpreting this and other precipitation datasets (see Chen and Knutson 2008 for a thorough analysis of the effect of resolution on precipitation extremes).  Errors in calculation and interpretation abound when precipitation datasets of different spatial resolutions are compared.  Rain rates, and especially the distribution of rain rates at a particular location, depend strongly on the spatial resolution of the dataset.  For example, a measure of extreme rain (e.g., 99th percentile rain rate) is expected to be very different in a time series observed from a surface rain gauge and in a co-located pixel of a gridded precipitation dataset such as TRMM 3B42, even if the data have the same temporal resolution. </p> <p class="Body">In order to compare two precipitation datasets on grids with different resolutions, one should typically regrid one or both of the datasets to a common grid using a regridding method that conserves the total amount of rain falling in an area. Often, the default interpolation in an analysis software package is bilinear interpolation (e.g., Matlab), which is not conservative.  One conservative regridding method is described in Jones (1999). The NCL language offers two methods to perform conservative regridding: <a href="http://www.ncl.ucar.edu/Document/Functions/Built-in/area_conserve_remap.shtml">area_conserve_remap</a>  or, the more robust, <a href="http://www.ncl.ucar.edu/Applications/ESMF.shtml">Earth System Modeling Framework (ESMF) regridding</a>. See also the Climate Data Guide's regridding page (<a href="https://climatedataguide.ucar.edu/climate-data-tools-and-analysis/regridding-overview">https://climatedataguide.ucar.edu/climate-data-tools-and-analysis/regridding-overview</a>).</p> <p class="Body"> The uniform spatial grid of this dataset lends itself to comparison with climate models, as long as care is taken to put the data on comparable grids.  The model precipitation data should be accumulated, rather than instantaneous, precipitation rate for comparison with TRMM 3B42.  One could compare climatologies over the same time period, or compare variations in time by examining model integrations forced with prescribed SSTs (AMIP experiments) and historical forcing (see, e.g., Pendergrass 2013 for composites over warm and cold ENSO phases in CMIP5 AMIP experiments).</p> <p class="Body"> Other combined satellite-gauge precipitation datasets are listed by the International Precipitation Working Group and can be found here: <a href="http://www.isac.cnr.it/~ipwg/data/datasets1.html">http://www.isac.cnr.it/~ipwg/data/datasets1.html</a>.  One notable dataset which also combines satellite and rain gauge measurements, but with lower resolution in time and space (daily, one degree in latitude and longitude with global coverage) is GPCP 1dd. PERSIANN and CMORPH are other datasets with sub-daily temporal resolution and high spatial resolution. The Climate Data Guide has an overview of these and many more precipitation datasets <a href="/climate-data/precipitation-data-sets-overview-comparison-table">here</a>.</p> <p class="Body">The research-grade standard TRMM 3B42 product should not be confused with the real-time product TRMM 3B42RT (documented in Huffman and Bolvin 2012). The main difference is that the standard delayed product incorporates further calibration. </p> <p class="Body">Some corrections have been made to account for the changes in satellites used to generate this dataset over time. Direct estimates of rain rate come from TRMM’s precipitation radar and microwave radiometer, which are sparse in time and space, so much of the utility of this datasets is it’s extension from these sparse measurements of rain rate onto higher temporal resolution infrared measurements from geostationary satellites.  Different IR datasets are used before 6 Feb 2000 and from 7 Feb onward.  Separate calibrations for each satellite (of which there are many) are involved, separately over land and ocean and for different latitude bands.  These are documented here: <a href="http://trmm.gsfc.nasa.gov/3b42.html">http://trmm.gsfc.nasa.gov/3b42.html</a>. </p> <p class="Body"> There are some potentially spurious features in the temporal record.  Liu and Allan (2012), Figure 2c, shows substantial disagreement of the monthly-mean, deseasonalized tropical precipitation anomalies over ocean between version 6 of TRMM 3B42 and other satellite-based precipitation datasets, including GPCP.  This is particularly relevant for studies of inter annual precipitation variability over the ocean.  See the figure here for an updated figure with version 7 data (the most recent).  Note that the datasets show much more agreement over land than over ocean, which is expected because both datasets incorporate monthly rain gauge measurements over land (but not ocean)." ##</p> </div> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--text-long.html.twig' --> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> <!-- THEME DEBUG --> <!-- THEME HOOK: 'block' --> <!-- FILE NAME SUGGESTIONS: * block--field-block--field-expert-developer-guidance.html.twig * block--field-block--node--climate-dataset--field-expert-developer-guidance.html.twig * block--field-block--node--climate-dataset.html.twig * block--field-block--node.html.twig * block--field-block.html.twig * block--layout-builder.html.twig x block.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> <div class="block block-layout-builder block-field-blocknodeclimate-datasetfield-expert-developer-guidance"> <h2 class="mb-md-2">Expert Developer Guidance</h2> <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--climate-dataset---custom--field-expert-developer-guidance.html.twig * field--node--field-expert-developer-guidance---custom.html.twig * field--node--climate-dataset--field-expert-developer-guidance.html.twig * field--node--field-expert-developer-guidance--climate-dataset--default.html.twig * field--node--field-expert-developer-guidance--climate-dataset.html.twig * field--node--field-expert-developer-guidance.html.twig * field--node--climate-dataset.html.twig * field--field-expert-developer-guidance.html.twig x field--text-long.html.twig * field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--text-long.html.twig' --> <div class="clearfix text-formatted field field--name-field-expert-developer-guidance field--type-text-long field--label-visually_hidden"> <div class="field__label visually-hidden">Expert Developer Guidance</div> <div class="field__item"><p class="Body">The following was contributed by Dr. George J. Huffman (NASA), October, 2014:</p> <p class="Body"> (updated December 5, 2018 and February 14, 2021)</p> <p class="Body"><strong>"TRMM Multi-Satellite Precipitation Analysis (TMPA)</strong></p> <p><strong>Suitability for Climate Research</strong></p> <p>A long-term, near-global gridded precipitation dataset may be categorized as a High-Resolution Precipitation Product (HRPP), which strives to provide the best instantaneous precip estimates, or as a Climate Data Record (CDR), which emphasizes homogeneity over instantaneous accuracy.  Of course, each approach tries to maintain the “other” goal, but it is secondary.  The TMPA is an HRPP, while the GPCP conforms to CDR standards.  As such, the TMPA depends on a continuously varying “virtual constellation” of satellites of opportunity, currently some 11 microwave satellites operated by 6 agencies.  Particularly early in the TMPA record, there were relatively few microwave satellites.  The flip side of this is that the early part of the TMPA record has over 50% coverage by microwave-calibrated IR estimates, and the IR coverage declines to 20% coverage in some recent years.  Such variations should steer users away from the TMPA to the GPCP for climate studies.  Additionally, the TMPA’s ~20-year record is really not sufficient for climate studies.  On the other hand, analyzing the TMPA in parallel with the GPCP can give some insight by confirming particular results or not.  One result that is nearly automatic is that the GPCP and TMPA agree rather closely at the monthly scale over most land areas because they both use the same GPCC monthly gauge analyses, and in similar ways.  Finally, precipitation analyses in general, and satellite algorithms specifically, emphasize some version of “most likely” statistics.  This fact implies that studies of extremes need to be realistic about what these products can be asked to do.</p> <p><strong>Interpreting Rainfall Estimates as a Function of Rain Rate</strong></p> <p>If you plot observed versus satellite precipitation grid values at the full 0.25° 3-hourly resolution the skill is modest, with huge relative error at small precipitation rates.  Studies show that time and/or space averaging substantially reduces the random error, characteristically collapsing the scatterplot toward the 1:1 line.  The point of handing out the data at fine scales with large uncertainty is that the <span style="text-decoration: underline;">user</span> has the freedom to create averages in ways that best correspond to the problem at hand.  In contrast, the relatively well-behaved 3B43 (monthly TMPA) forces the user to use data in calendar-month units; a monthly average from one month’s mid-point to the next is not possible.  At the fine scales in full-resolution 3B42, we usually observe that random error dominates the error budget – that is, the part of the error that averages out with sufficiently long averaging.  The bias (the persistent part of the error that tends to bedevil climate studies) is hard to estimate, although we have tried to make a fair estimate of the “real” climatology for TRMM:</p> <p>Wang, J.-J., R.F. Adler, G.J. Huffman, D.F. Bolvin, 2014:  An Updated TRMM Composite Climatology of Tropical Rainfall and Its Validation.  <em>J. of Climate</em>, <strong>27</strong>(1), 273-284.</p> <p>It is fair to say that error estimates are lagging behind where we expected them to be.  However, recent work shows some promise of getting a handle on error estimation, for example using the work by Maggioni and collaborators:</p> <p>Maggioni, V., M.R.P. Sapiano, R.F. Adler, Y. Tian, G.J. Huffman, 2014:  An Error Model for Uncertainty Quantification in High-Time Resolution Precipitation Products.  <em>J. Hydrometeor.</em>, <strong>15</strong>(3), doi:10.1175/JHM-D-13-0112.1, 1274-1292.</p> <p>There is some hope that this approach will naturally encompass both random and bias errors.  The cost is that we’re going to end up with quantiles of estimated precip at each time at each grid box.  Such detail will not be suitable for all users, so we will need to produce a simplified error estimate as well.</p> <p> The Behrangi et al. (2014) paper</p> <p>Behrangi, A., G. Stephens, R.F. Adler, G.J. Huffman, B. Lambrigtsen, M. Lebsock, 2014:  An Update on Oceanic Precipitation Rate and Its Zonal Distribution in Light of Advanced Observations from Space.  <em>J. Climate</em>, <strong>27</strong>(11), doi: 10.1175/JCLI-D-13-00679.1, 3957-3965.</p> <p>provides a more-quantitative view of the bias errors that we’ve long suspected.  The seriousness of the results depend on which statistics you’re trying to use: how important is it to get the lightest precip rates right that give 5% of the amount, but 40% of the events, or whatever the numbers are in the area of interest?  Essentially all the precip data set algorithms have focused on getting the averages right, and it’s a much more challenging problem to <span style="text-decoration: underline;">also</span> get the distribution of precip rates quantitatively correct.</p> <p><strong>Algorithm and Processing</strong></p> <p>See the accompanying Technical Notes and links therein for a description of the steps involved in producing the TMPA products.  To summarize, The Tropical Rainfall Measuring Mission (TRMM) is a joint U.S.-Japan satellite mission to monitor tropical and subtropical precipitation and to estimate its associated latent heating.  TRMM was successfully launched on November 27, 1997 at 4:27 PM (EST) from the Tanegashima Space Center in Japan.  The precipitation-relevant instruments on the TRMM satellite include the Precipitation Radar (PR), an electronically scanning radar operating at 13.8 GHz; TRMM Microwave Image (TMI), a nine-channel passive microwave radiometer; and Visible and Infrared Scanner (VIRS), a five-channel visible/infrared radiometer.</p> <p>The purpose of the 3B42 algorithm is to produce TRMM- and raingauge-adjusted multi-satellite precipitation rate (in mm/hr) and root-mean-square (RMS) precipitation-error estimates.  The algorithm combines multiple independent precipitation estimates from the TMI, Advanced Microwave Scanning Radiometer for Earth Observing Systems (AMSR-E), Special Sensor Microwave Imager (SSMI), Special Sensor Microwave Imager/Sounder (SSMIS), Advanced Microwave Sounding Unit (AMSU), Microwave Humidity Sounder (MHS), and microwave-adjusted merged geo-infrared (IR).  All input microwave data are intercalibrated to TRMM Combined Instrument (TCI) precipitation estimates (TRMM product 2B31); the IR estimates are computed using monthly matched microwave-IR histogram matching; then missing data in individual 3-hourly merged-microwave fields are filled with the IR estimates.  After the preprocessing is complete, the 3-hourly multi-satellite fields are summed for the month and combined with the monthly accumulated Global Precipitation Climatology Centre (GPCC) rain gauge analysis using inverse-error-variance weighting to form a monthly best-estimate precipitation rate, which is TRMM Product 3B43.  The final step is to scale all the 3-hourly estimates for the month to sum to the monthly value (for each gridbox separately).  The final 3B42 precipitation (in mm/hr) estimates have a 3-hourly temporal resolution and a 0.25°x0.25° spatial resolution.  The spatial coverage is the latitude band 50°S to 50°N.</p> <p>Limits are imposed on the scaling to avoid unphysical results, so particularly in low-rain areas, the 3B42 values in a month may not sum exactly to the corresponding 3B43.  For this reason, 3B43 is the preferred dataset for monthly values.</p> <p><strong>Version 7 Updates</strong></p> <p>The TRMM data system was designed to provide episodic, complete reprocessings of the TRMM products to take advantage of ongoing research to improve the various scientific algorithms.  [Subsequently, such reprocessing has come to be viewed as a best practice for data archives in general.]  The latest reprocessing for TRMM moved the products from Version 6 to 7, and the current data set has been processed using the Version 7 algorithms.</p> <p>Quoting from the technical document for the TMPA,</p> <p>Huffman, G.J., D.T. Bolvin, 2018:  TRMM and Other Data Precipitation Data Set Documentation.  NASA/GSFC,  <a href="https://pmm.nasa.gov/sites/default/files/document_files/3B4XRT_doc_V7_180426.pdf" target="_blank"><em>https://pmm.nasa.gov/sites/default/files/document_files/3B4XRT_doc_V7_180426.pdf</em></a> , 51 pp.</p> <p>and noting well that there are differences over both land and ocean:</p> <p>The *<em>transition from Version 6 to Version 7</em>* for TRMM datasets occurred on 30 June 2011, with June 2011 being the final month of Version 6 data.  Thereafter, the Precipitation Processing System (PPS) was reconfigured to start the parallel activities of Version 7 “initial processing” (IP) for new data (starting 1 July 2011), and Version 7 reprocessing (RP) for the entire archive starting 1 January 1998.  The TMPA lagged the other TRMM products to allow for calibration and to finalize use of SSMIS data.  This release incorporated several important changes as part of the upgrade to Version 7:</p> <p>•   Additional satellites, including the early parts of the MHS record, the entire operational SSMIS record, and slots for future satellites.</p> <p>•   A new IR brightness temperature dataset for the period before the start of the CPC 4-km Merged Global IR Dataset (i.e., January 1998 – February 2000).  Unlike the old GPCP histograms used in Version 6, the NCDC GridSat-B1 features spatial resolution finer than the TMPA 0.25 grid and full coverage of the TMPA domain.</p> <p>•   Uniformly reprocessed input data using current algorithms, most notably for AMSU and MHS, but also including TCI, TMI, AMSR-E, and SSMI.</p> <p>•   Use of a single, uniformly processed surface precipitation gauge analysis using current algorithms as computed by the Global Precipitation Climatology Centre (GPCC).</p> <p>•   Use of a latitude-band calibration scheme for all satellites (see “HQ”).</p> <p>•   Additional output fields in the data files, including sensor-specific source and overpass time.</p> <p> </p> <p>The complete Version 6 archive was maintained for public access throughout and beyond the cutover to Version 7. For Initial Processing (IP), our switch to the GPCC gauge analysis necessitates increasing the latency of the products from 10 days after the month, which was the case in Version 6, to about two months after the end of the month.  The initial Version 7 release occurred in May 2012, while the second set was posted in December 2012.</p> <p>Initial testing showed that the revisions eliminated the unrepresentatively low bias in ocean values for 2001-2007 that were related to how we treated an early version of AMSU-based precipitation in Version 6.  However, we found that the V7 tropical-ocean average precipitation is consistently some 5% higher than the combined TMI-PR product (2B31) that serves as the calibrator.  The basis for this difference is not explicated at this point, but the value is small enough and consistent enough that we chose to release the data.</p> <p>Note: As discussed below, up through September 2014 calibration to TCI was computed on a month-to-month basis.  Thereafter, the shutdown of the PR required a climatologically based calibration.  This change introduces a data boundary that must be examined for impact on each user’s application.</p> <p><strong>Making the Transition from TRMM to GPM Data Sets</strong></p> <p>TRMM ran out of fuel in mid-2014 and began a slow descent.  As well, there were some battery issues.  By 7 October 2014, the satellite descended to an altitude that precluded useful radar data, which necessitated a different calibration procedure for 3B42 starting with October 2014 data.  This implies at least a slight inhomogeneity, primarily over the oceans because we know that calibrations involving PR have a different interannual behavior than calibrations based solely on passive microwave.  All TMPA production ceased with the last datafile date/time for 2019.</p> <p>We recognized that the real-time version of 3B42, 3B42RT, had a strong application focus, and expect to run it until the equivalent IMERG products are satisfactory, which happened in mid-2020.  Undoubtedly, users wanted the old product forever, but at some point we had to stop.</p> <p>The retrospective processing for IMERG that we released in mid-2020 took us back to June 2000.  The goal is January 1998, the start of TRMM, but one of the critical input datasets for IMERG is not now available before mid-February 2000 in the correct form. This is equally true for all runs, including the Final.  Given the sea change in algorithms, this first general GPM reprocessing across the TRMM era stands as the final TRMM reprocessing, since the GPM products (including IMERG) cover the same period and are better than the old TRMM-specific algorithms.</p> <p> </p> <p>For more details on the TRMM-to-GPM transition, see</p> <p><em><a href="https://gpm.nasa.gov/resources/documents/transition-multi-satellite-products-trmm-gpm-tmpa-imerg" target="_blank">https://gpm.nasa.gov/resources/documents/transition-multi-satellite-products-trmm-gpm-tmpa-imerg</a> .</em></p> <p>As things move along, the Global Precipitation Measurement mission (GPM) web site,</p> <p><a href="https://gpm.nasa.gov/data/news" target="_blank"><em>https://gpm.nasa.gov/data/news</em></a>,</p> <p>is the right general source for news.  As well, it hosts has a one-stop set of web pages specifically aimed at new users, listing all of the basic and derived TRMM and GPM datasets available through Goddard Space Flight Center:</p> <p> <em><a href="https://gpm.nasa.gov/data/directory" target="_blank">https://gpm.nasa.gov/data/directory</a>.</em></p> <p> These pages include documentation about the data sets and algorithms, and contact information.  IMERG-specific announcements will be posted to the IMERG mailing list, to which precipitation data users may subscribe (just ask through <a href="https://gpm.nasa.gov/contact" target="_blank"><em>https://gpm.nasa.gov/contact</em></a>).</p> <p class="Body">##</p> <div> </div> </div> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--text-long.html.twig' --> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> </main> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/layout/layout--twocol-section.html.twig' --> Tue, 15 Nov 2011 14:37:00 +0000 ryanj 672 at https://climatedataguide.ucar.edu Nino SST Indices (Nino 1+2, 3, 3.4, 4; ONI and TNI) https://climatedataguide.ucar.edu/climate-data/nino-sst-indices-nino-12-3-34-4-oni-and-tni <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--climate-dataset--rss--title.html.twig * field--node--title--rss.html.twig * field--node--climate-dataset--title.html.twig * field--node--title--climate-dataset.html.twig x field--node--title.html.twig * field--node--climate-dataset.html.twig * field--title.html.twig * field--string.html.twig * field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--node--title.html.twig' --> <span class="field field--name-title field--type-string field--label-hidden">Nino SST Indices (Nino 1+2, 3, 3.4, 4; ONI and TNI)</span> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--node--title.html.twig' --> <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> 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'profiles/composer/unity-profile/themes/unity/templates/field/field--node--uid.html.twig' --> <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--climate-dataset--rss--created.html.twig * field--node--created--rss.html.twig * field--node--climate-dataset--created.html.twig * field--node--created--climate-dataset.html.twig x field--node--created.html.twig * field--node--climate-dataset.html.twig * field--created.html.twig * field--created.html.twig * field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--node--created.html.twig' --> <span class="field field--name-created field--type-created field--label-hidden">Sun, 11/06/2011 - 06:50</span> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--node--created.html.twig' --> <!-- THEME DEBUG --> <!-- THEME HOOK: 'layout__twocol_section' --> <!-- FILE NAME SUGGESTIONS: x layout--twocol-section.html.twig x 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</li> <li class="breadcrumb-item"> <a href="/domains/tropics">Tropics</a> </li> </ol> </nav> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/navigation/breadcrumb.html.twig' --> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> </div> <main class="layout__region layout__region--main main-content-wrapper"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'block' --> <!-- FILE NAME SUGGESTIONS: * block--field-block--field-primary-image.html.twig * block--field-block--node--climate-dataset--field-primary-image.html.twig * block--field-block--node--climate-dataset.html.twig * block--field-block--node.html.twig * block--field-block.html.twig * block--layout-builder.html.twig x block.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> <div class="block block-layout-builder block-field-blocknodeclimate-datasetfield-primary-image"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--climate-dataset---custom--field-primary-image.html.twig * field--node--field-primary-image---custom.html.twig * field--node--climate-dataset--field-primary-image.html.twig * field--node--field-primary-image--climate-dataset--default.html.twig * field--node--field-primary-image--climate-dataset.html.twig * field--node--field-primary-image.html.twig * field--node--climate-dataset.html.twig * field--field-primary-image.html.twig * field--entity-reference.html.twig x field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field.html.twig' --> <div class="field field--name-field-primary-image field--type-entity-reference field--label-visually_hidden"> <div class="field__label visually-hidden">Teaser image</div> <div class="field__item"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'image_formatter' --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/image-formatter.html.twig' --> <!-- THEME DEBUG --> <!-- THEME HOOK: 'image' --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/image.html.twig' --> <img src="/sites/default/files/2022-03/oni.monthly.smoo_stro.png" width="949" height="436" alt="Nino SST Indices (Nino 1+2, 3, 3.4, 4; ONI and TNI)" loading="lazy" typeof="foaf:Image" class="img-fluid" /> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/image.html.twig' --> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/image-formatter.html.twig' --> </div> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field.html.twig' --> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> <!-- THEME DEBUG --> <!-- THEME HOOK: 'block' --> <!-- FILE NAME SUGGESTIONS: x block--field-block--field-main-content.html.twig * block--field-block--node--climate-dataset--field-main-content.html.twig * block--field-block--node--climate-dataset.html.twig * block--field-block--node.html.twig * block--field-block.html.twig * block--layout-builder.html.twig * block.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block--field-block--field-main-content.html.twig' --> <div class="mt-3 mt-md-4 block block-layout-builder block-field-blocknodeclimate-datasetfield-main-content"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--climate-dataset---custom--field-main-content.html.twig * field--node--field-main-content---custom.html.twig * field--node--climate-dataset--field-main-content.html.twig * field--node--field-main-content--climate-dataset--default.html.twig * field--node--field-main-content--climate-dataset.html.twig * field--node--field-main-content.html.twig * field--node--climate-dataset.html.twig * field--field-main-content.html.twig * field--entity-reference-revisions.html.twig x field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field.html.twig' --> <div class="field field--name-field-main-content field--type-entity-reference-revisions field--label-visually_hidden"> <div class="field__label visually-hidden">Main content</div> <div class="field__items"> <div class="field__item"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'paragraph' --> <!-- FILE NAME SUGGESTIONS: * paragraph--climate-dataset--rich-text.html.twig * paragraph--rich-text--.html.twig * paragraph--rich-text--default.html.twig * paragraph--rich-text.html.twig * paragraph--default.html.twig x paragraph.html.twig --> <!-- BEGIN OUTPUT from 'modules/composer/paragraphs/templates/paragraph.html.twig' --> <div class="paragraph paragraph--type--rich-text paragraph--view-mode--default"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--paragraph--field-body--default--climate-dataset.html.twig * field--rich-text--default--field-body.html.twig * field--paragraph--field-body--default.html.twig * field--paragraph--rich-text--field-body.html.twig * field--paragraph--field-body--rich-text.html.twig * field--paragraph--field-body.html.twig * field--paragraph--rich-text.html.twig * field--field-body.html.twig x field--text-long.html.twig * field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--text-long.html.twig' --> <div class="clearfix text-formatted field field--name-field-body field--type-text-long field--label-hidden field__item"><p>There are several indices used to monitor the tropical Pacific, all of which are based on SST anomalies averaged across a given region.  Usually the anomalies are computed relative to a base period of 30 years.  The Niño 3.4 index and the Oceanic Niño Index (ONI) are the most commonly used indices to define El Niño and La Niña events.  Other indices are used to help characterize the unique nature of each event. A discussion of El Niño and its impacts is provided in the <a href="/climate-data/nino-sst-indices-nino-12-3-34-4-oni-and-tni?qt-climatedatasetmaintabs=1#qt-climatedatasetmaintabs">Expert Guidance</a> by Dr. Kevin Trenberth.</p> <p><img alt="" height="87" src="/sites/default/files/users/dschneid/key_figures_428.png" style="margin-left:5px; margin-right:5px; float:left" width="283" />The numbers of the Niño 1,2,3, and 4 regions correspond with the labels assigned to ship tracks that crossed these regions.  Data from these tracks enabled the historic records of El Niño to be carried back in time to 1949, as discussed in a classic study by Rasmusson and Carpenter (1982).</p> <p>Niño 1+2 (0-10S, 90W-80W):  The Niño 1+2 region is the smallest and eastern-most of the Niño SST regions, and corresponds with the region of coastal South America where El Niño was first recognized by the local populations.  This index tends to have the largest variance of the Niño SST indices.</p> <p>Niño 3 (5N-5S, 150W-90W):  This region was once the primary focus for monitoring and predicting El Niño, but researchers later learned that the key region for coupled ocean-atmosphere interactions for ENSO lies further west (Trenberth, 1997).  Hence, the Niño 3.4 and ONI became favored for defining El Niño and La Niña events.</p> <p>Niño 3.4 (5N-5S, 170W-120W):  The  Niño 3.4 anomalies may be thought of as representing the average equatorial SSTs across the Pacific from about the dateline to the South American coast.  The Niño 3.4 index typically uses a 5-month running mean, and El Niño or La  Niña events are defined when the  Niño 3.4 SSTs exceed +/- 0.4C for a period of six months or more.</p> <p>ONI (5N-5S, 170W-120W): The ONI uses the same region as the Niño 3.4 index.  The ONI uses a 3-month running mean, and to be classified as a full-fledged El Niño or La Niña, the anomalies must exceed +0.5C or -0.5C for at least five consecutive months.  This is the operational definition used by NOAA.</p> <p>Niño 4 (5N-5S, 160E-150W): The  Niño 4 index captures SST anomalies in the central equatorial Pacific.  This region tends to have less variance than the other Niño regions.</p> <p>To define the unique character of each El Niño or La Niña event, Trenberth and Stepaniak (2001) argue that the Niño 3.4 index should be used in combination with an index that  they introduce, called the Trans-Niño Index (TNI).  The TNI is defined to be the difference in normalized SST anomalies between the Niño 1+2 and Niño 4 regions.  The TNI thus measures the gradient in SST anomalies between the central and eastern equatorial Pacific.  When the SST gradient is particularly large (say, due to positive anomalies in the Niño 4 region and negative anomalies in the Niño 1+2 region), some researchers classify the event as a "central Pacific El Niño " or "El  Niño Modoki," although the distinction of this type of event as a seperate phenonomenon is a matter or debate.</p> <p>'Recipes' for computation of the Niño SST indices are given the the Technical Notes section of the Expert Guidance tab.</p> <p> </p> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--text-long.html.twig' --> </div> <!-- END OUTPUT from 'modules/composer/paragraphs/templates/paragraph.html.twig' --> </div> </div> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field.html.twig' --> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block--field-block--field-main-content.html.twig' --> <!-- THEME DEBUG --> <!-- THEME HOOK: 'block' --> <!-- FILE NAME SUGGESTIONS: * block--field-block--field-expert-user-guidance.html.twig * block--field-block--node--climate-dataset--field-expert-user-guidance.html.twig * block--field-block--node--climate-dataset.html.twig * block--field-block--node.html.twig * block--field-block.html.twig * block--layout-builder.html.twig x block.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> <div class="block block-layout-builder block-field-blocknodeclimate-datasetfield-expert-user-guidance"> <h2 class="mb-md-2">Expert User Guidance</h2> <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--climate-dataset---custom--field-expert-user-guidance.html.twig * field--node--field-expert-user-guidance---custom.html.twig * field--node--climate-dataset--field-expert-user-guidance.html.twig * field--node--field-expert-user-guidance--climate-dataset--default.html.twig * field--node--field-expert-user-guidance--climate-dataset.html.twig * field--node--field-expert-user-guidance.html.twig * field--node--climate-dataset.html.twig * field--field-expert-user-guidance.html.twig x field--text-long.html.twig * field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--text-long.html.twig' --> <div class="clearfix text-formatted field field--name-field-expert-user-guidance field--type-text-long field--label-visually_hidden"> <div class="field__label visually-hidden">Expert User Guidance</div> <div class="field__item"><p>The following was contributed by Dr. Kevin Trenberth, NCAR, January, 2016.  These comments were originally published on The Conversation. Read the <a href="https://theconversation.com/what-north-america-can-expect-from-el-nino-51959" target="_blank">original article</a>.</p> <p>A major El Niño is under way now. It already has substantially influenced weather patterns around the globe, but could have even bigger impacts this winter. There have been only two “super” El Niños until now: in 1982-83 and 1997-98. We are now experiencing a third “super” El Niño.</p> <p>Every El Niño cycle is different. The effects from this year’s already include a record number of hurricanes/typhoons in the Pacific and intense wildfires in Indonesia.</p> <p>In the United States over the next several months, El Niño is expected to cause heavy rains across the South, with the potential for coastal flooding in California, along with relatively mild and dry weather in the northern states. Global climate change, which, along with the El Niño, is making 2015 the warmest year on record, is likely to amplify these impacts.</p> <h2>What is El Niño?</h2> <p>El Niños are not uncommon. Every three to seven years or so, the surface waters of the tropical Pacific Ocean become extremely warm from the International Dateline to the west coast of South America. This process causes changes in the local and regional ecology, and is clearly linked with abnormal global climate patterns.</p> <p>Historically “El Niño” referred to the appearance of unusually warm water off the coast of Peru near Christmastime (Niño is Spanish and refers to “the boy Christ child”). Today it describes broader changes that occur across the Pacific basin.</p> <p>Oceanic and atmospheric conditions in the tropical Pacific fluctuate somewhat irregularly between warm El Niño phases and cold phases in which surface waters cool across the tropical Pacific. These cooling events are called “La Niña” (“the girl” in Spanish). The most intense phase of each event typically lasts about a year.</p> <p>El Niño is linked to major changes in the atmosphere known as the Southern Oscillation (SO). Scientists call the whole phenomenon the El Niño–Southern Oscillation (ENSO). During El Niño, higher-than-normal surface air pressures develop over Australia, Indonesia, Southeast Asia and the Philippines, producing drier conditions or even droughts. Dry conditions also prevail in Hawaii, parts of Africa, and northeastern Brazil and Colombia.</p> <p>Lower pressures develop over the central and eastern Pacific, along the west coast of South America, parts of South America near Uruguay and southern parts of the United States in winter, often producing heavy rains and flooding. Regions that are typically dry during El Niño events tend to become excessively wet during La Nina events, and vice versa.</p> <h2>Why does El Niño happen?</h2> <p>ENSO is a natural phenomenon arising from coupled interactions between the atmosphere and the ocean in the tropical Pacific Ocean. Changing sea surface temperatures alter rainfall and surface winds, which in turn alter ocean currents and sea surface temperatures. These interactions produce a positive feedback loop, in which each change tends to promote further changes. There is good evidence from core samples taken from coral reefs and glacial ice in the Andes that ENSO has been going on for millennia.</p> <p>During El Niño, trade winds that typically blow from east to west across the Pacific weaken. Sea level falls in the western Pacific and rises in the east by as much as a foot as warm waters surge eastward along the equator. The resulting increase in sea temperatures warms and moistens the overlying air. This triggers a process called convection: the warm, moist air rises into the atmosphere, altering normal rainfall patterns and associated releases of heat.</p> <p>Somewhat like a rock sitting in a stream of water, this unusual heating sets up teleconnections: continental-scale waves in the atmosphere that extend into the midlatitudes in winter. These waves alter winds and change the jet stream and storm tracks, creating persistent weather patterns. The changes in sea surface temperatures associated with El Niño reach their most extreme point during winter in the Northern Hemisphere, so we see the biggest effects then.</p> <h2>The 2015-16 El Niño event</h2> <p>Because Pacific surface waters are much warmer and atmospheric circulation patterns throughout the tropics are altered, fewer tropical storms and hurricanes than normal occur in the tropical Atlantic during El Niño. But there is much more activity than usual in the Pacific. Super Typhoon Pam, which ripped through Vanuatu in March 2015 causing enormous damage, was fueled by warm waters from El Niño.</p> <p>During the northern Pacific hurricane season in the summer and fall of 2015, 25 category 4 and 5 hurricanes/typhoons developed, a record as compared to the previous record of 18. Changed weather patterns resulted in lack of rain and thus strong drought and wildfires in Indonesia that have degraded air quality over hundreds of miles.</p> <p>El Niño has recently affected the Indian Ocean. The Bay of Bengal is already exceptionally warm, which has led to record-breaking rains and widespread flooding and devastation in Chennai, southeastern India, with 47 inches of rain in November and a further 11 inches of rain in the first week of December. This Indian Ocean activity may disrupt the expected development of El Niño patterns around the world. El Niño-related heavy rains have also recently (December 2015) occurred in the Americas: in Paraguay and surrounding areas, and in Missouri. The latter has led to considerable flooding of the Mississippi, reminiscent of the El Niño-related Mississippi flooding in 1993.</p> <p>Sea surface temperature anomalies from El Niño tend to peak in December, and this year the changes may already have peaked in late November. However, the seasonal cycle further increases total sea surface temperatures, so the biggest impacts on the atmosphere often occur in the following February or March. This El Niño began in 2014, but stalled, and then regrouped in 2015. Every El Niño event is different, but according to NOAA’s latest monthly outlook, El Niño conditions are expected to peak during the winter of 2015-16 before gradually weakening through spring 2016 and terminating by late spring or early summer 2016.</p> <p>During the coming months, climate scientists expect that El Niño will pull the east Pacific Northern Hemisphere jet stream and its associated storm track southward. Normally these storms veer to the north toward the Gulf of Alaska or enter North America near British Columbia and Washington, where they often link up with cold Arctic and Canadian air masses and bring them down into the United States. Instead, with the jet stream following an altered path, the northern states are likely to experience relatively mild and drier-than-normal weather. Storms tracking across the continent further to the south will likely create wet conditions in California and across the South as far east as Florida.</p> <p>Each El Niño event has its own character. In the El Niño winters of 1992–93, 1994–95, 1997–98 and 2004-05, southern California was battered by storms and experienced flooding and coastal erosion. However, in more modest El Niños, including the 1986–87 and 1987–88 winters, California was more at risk from droughts. Given the scale of this year’s El Niño, Californians should prepare for heavy rains, possible flooding and heavy coastal erosion, driven by the combined effects of higher sea levels (driven by climate change and El Niño effects) and storm surges.</p> <h2>El Niño and global warming</h2> <p>All of the impacts of El Niño are exacerbated by global warming. Globally, temperatures for 2015 are the highest on record, in part because of the El Niño event. Global warming sets the background and El Niño determines regional weather patterns. When they work together in the same direction, they have the biggest effects and records are broken.</p> <p>Changes associated with El Niño, including droughts, floods, heat waves and other changes, take a heavy toll in many parts of the world. They can severely disrupt agriculture, fisheries, the environment, health, energy demand and air quality, and increase the risks of wildfires. The risk of adverse effects and more frequent extremes or even records occurring is heightened by global climate change from human activities.</p> <p>By better understanding El Niño, predictions and alerts can allow us to be prepared for possible unusual effects, but we can and should act to slow down climate change.##</p> <p><img alt="The Conversation" height="1" src="https://counter.theconversation.edu.au/content/51959/count.gif" style="display: none ! important;" width="1" /></p> </div> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--text-long.html.twig' --> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> </main> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/layout/layout--twocol-section.html.twig' --> Sun, 06 Nov 2011 13:50:00 +0000 ryanj 650 at https://climatedataguide.ucar.edu Southern Oscillation Indices: Signal, Noise and Tahiti/Darwin SLP (SOI) https://climatedataguide.ucar.edu/climate-data/southern-oscillation-indices-signal-noise-and-tahitidarwin-slp-soi <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--climate-dataset--rss--title.html.twig * field--node--title--rss.html.twig * field--node--climate-dataset--title.html.twig * field--node--title--climate-dataset.html.twig x field--node--title.html.twig * field--node--climate-dataset.html.twig * field--title.html.twig * field--string.html.twig * field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--node--title.html.twig' --> <span class="field field--name-title field--type-string field--label-hidden">Southern Oscillation Indices: Signal, Noise and Tahiti/Darwin SLP (SOI)</span> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--node--title.html.twig' --> <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--climate-dataset--rss--uid.html.twig * field--node--uid--rss.html.twig * field--node--climate-dataset--uid.html.twig * field--node--uid--climate-dataset.html.twig x field--node--uid.html.twig * field--node--climate-dataset.html.twig * field--uid.html.twig * field--entity-reference.html.twig * field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--node--uid.html.twig' --> <span class="field field--name-uid field--type-entity-reference field--label-hidden"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'username' --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/user/username.html.twig' --> <span lang="" about="/user/2" typeof="schema:Person" property="schema:name" datatype="">ryanj</span> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/user/username.html.twig' --> </span> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--node--uid.html.twig' --> <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--climate-dataset--rss--created.html.twig * field--node--created--rss.html.twig * field--node--climate-dataset--created.html.twig * field--node--created--climate-dataset.html.twig x field--node--created.html.twig * field--node--climate-dataset.html.twig * field--created.html.twig * field--created.html.twig * field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--node--created.html.twig' --> <span class="field field--name-created field--type-created field--label-hidden">Fri, 11/04/2011 - 10:34</span> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--node--created.html.twig' --> <!-- THEME DEBUG --> <!-- THEME HOOK: 'layout__twocol_section' --> <!-- FILE NAME SUGGESTIONS: x layout--twocol-section.html.twig x layout--twocol-section.html.twig * layout.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/layout/layout--twocol-section.html.twig' --> <div> <div class="layout__region layout__region--main-top breadcrumb-wrapper mt-2"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'block' --> <!-- FILE NAME SUGGESTIONS: * block--system-breadcrumb-block.html.twig * block--system.html.twig x block.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> <div class="block block-system block-system-breadcrumb-block"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'breadcrumb' --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/navigation/breadcrumb.html.twig' --> <nav class="mb-2 d-print-none" role="navigation" aria-labelledby="system-breadcrumb"> <h2 id="system-breadcrumb" class="visually-hidden">Breadcrumb</h2> <ol class="breadcrumb"> <li class="breadcrumb-item"> <a href="/">Home</a> </li> <li class="breadcrumb-item"> <a href="/domains/tropics">Tropics</a> </li> </ol> </nav> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/navigation/breadcrumb.html.twig' --> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> </div> <main class="layout__region layout__region--main main-content-wrapper"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'block' --> <!-- FILE NAME SUGGESTIONS: * block--field-block--field-primary-image.html.twig * block--field-block--node--climate-dataset--field-primary-image.html.twig * block--field-block--node--climate-dataset.html.twig * block--field-block--node.html.twig * block--field-block.html.twig * block--layout-builder.html.twig x block.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> <div class="block block-layout-builder block-field-blocknodeclimate-datasetfield-primary-image"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--climate-dataset---custom--field-primary-image.html.twig * field--node--field-primary-image---custom.html.twig * field--node--climate-dataset--field-primary-image.html.twig * field--node--field-primary-image--climate-dataset--default.html.twig * field--node--field-primary-image--climate-dataset.html.twig * field--node--field-primary-image.html.twig * field--node--climate-dataset.html.twig * field--field-primary-image.html.twig * field--entity-reference.html.twig x field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field.html.twig' --> <div class="field field--name-field-primary-image field--type-entity-reference field--label-visually_hidden"> <div class="field__label visually-hidden">Teaser image</div> <div class="field__item"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'image_formatter' --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/image-formatter.html.twig' --> <!-- THEME DEBUG --> <!-- THEME HOOK: 'image' --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/image.html.twig' --> <img src="/sites/default/files/2022-03/soi5.gif" width="1188" height="918" alt="Southern Oscillation Indices: Signal, Noise and Tahiti/Darwin SLP (SOI)" loading="lazy" typeof="foaf:Image" class="img-fluid" /> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/image.html.twig' --> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/image-formatter.html.twig' --> </div> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field.html.twig' --> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> <!-- THEME DEBUG --> <!-- THEME HOOK: 'block' --> <!-- FILE NAME SUGGESTIONS: x block--field-block--field-main-content.html.twig * block--field-block--node--climate-dataset--field-main-content.html.twig * block--field-block--node--climate-dataset.html.twig * block--field-block--node.html.twig * block--field-block.html.twig * block--layout-builder.html.twig * block.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block--field-block--field-main-content.html.twig' --> <div class="mt-3 mt-md-4 block block-layout-builder block-field-blocknodeclimate-datasetfield-main-content"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--climate-dataset---custom--field-main-content.html.twig * field--node--field-main-content---custom.html.twig * field--node--climate-dataset--field-main-content.html.twig * field--node--field-main-content--climate-dataset--default.html.twig * field--node--field-main-content--climate-dataset.html.twig * field--node--field-main-content.html.twig * field--node--climate-dataset.html.twig * field--field-main-content.html.twig * field--entity-reference-revisions.html.twig x field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field.html.twig' --> <div class="field field--name-field-main-content field--type-entity-reference-revisions field--label-visually_hidden"> <div class="field__label visually-hidden">Main content</div> <div class="field__items"> <div class="field__item"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'paragraph' --> <!-- FILE NAME SUGGESTIONS: * paragraph--climate-dataset--rich-text.html.twig * paragraph--rich-text--.html.twig * paragraph--rich-text--default.html.twig * paragraph--rich-text.html.twig * paragraph--default.html.twig x paragraph.html.twig --> <!-- BEGIN OUTPUT from 'modules/composer/paragraphs/templates/paragraph.html.twig' --> <div class="paragraph paragraph--type--rich-text paragraph--view-mode--default"> <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--paragraph--field-body--default--climate-dataset.html.twig * field--rich-text--default--field-body.html.twig * field--paragraph--field-body--default.html.twig * field--paragraph--rich-text--field-body.html.twig * field--paragraph--field-body--rich-text.html.twig * field--paragraph--field-body.html.twig * field--paragraph--rich-text.html.twig * field--field-body.html.twig x field--text-long.html.twig * field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--text-long.html.twig' --> <div class="clearfix text-formatted field field--name-field-body field--type-text-long field--label-hidden field__item"><p>The Southern Oscillation Index (SOI) is a time series used to characterize the large scale sea level pressure (SLP) patterns in the tropical Pacific. Monthly mean SLP at Tahiti [T] and Darwin [D] are used. An optimal SOI can be constructed. It consists of  [T-D] which is a measure of the large scale phenomena while  [T+D] is a measure of small scale and/or transient phenomena that are not part of the large scale Southern Oscillation. The SOI is linked to large scale tropical SST variability and as such is a measure of the "SO" part of the ENSO phenomenon. Extended periods of negative SOI correspond with El Nino events, characterized by warm SSTs in the eastern and central tropical Pacific.  It has a period of 2-8 years.</p> <p>SLP values for Tahiti prior to 1935 should be viewed with appropriate caution. Ropelewski and Jones (1987) discuss the issues. It is recommended that the  'Darwin only' version of the SOI be used for very long term studies. It is highly correllated with the (Tihiti-Darwin) record. An effort to extend the SOI series to prior than 1866 is discussed by Konnen et al (1998).</p> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--text-long.html.twig' --> </div> <!-- END OUTPUT from 'modules/composer/paragraphs/templates/paragraph.html.twig' --> </div> </div> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field.html.twig' --> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block--field-block--field-main-content.html.twig' --> <!-- THEME DEBUG --> <!-- THEME HOOK: 'block' --> <!-- FILE NAME SUGGESTIONS: * block--field-block--field-key-strengths.html.twig * block--field-block--node--climate-dataset--field-key-strengths.html.twig * block--field-block--node--climate-dataset.html.twig * block--field-block--node.html.twig * block--field-block.html.twig * block--layout-builder.html.twig x block.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> <div class="block block-layout-builder block-field-blocknodeclimate-datasetfield-key-strengths"> <h2 class="mb-md-2">Key Strengths</h2> <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--climate-dataset---custom--field-key-strengths.html.twig * field--node--field-key-strengths---custom.html.twig * field--node--climate-dataset--field-key-strengths.html.twig * field--node--field-key-strengths--climate-dataset--default.html.twig * field--node--field-key-strengths--climate-dataset.html.twig * field--node--field-key-strengths.html.twig * field--node--climate-dataset.html.twig * field--field-key-strengths.html.twig x field--text-long.html.twig * field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--text-long.html.twig' --> <div class="clearfix text-formatted field field--name-field-key-strengths field--type-text-long field--label-visually_hidden"> <div class="field__label visually-hidden">Key Strengths</div> <div class="field__items"> <div class="field__item"><p>Simple to construct and understand</p> </div> <div class="field__item"><p>Long record. The 'Darwin only' version of the SOI is high quality and highly correlated with the (Tahiti-Darwin) full version of the SOI.</p> </div> </div> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--text-long.html.twig' --> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> <!-- THEME DEBUG --> <!-- THEME HOOK: 'block' --> <!-- FILE NAME SUGGESTIONS: * block--field-block--field-key-limitations.html.twig * block--field-block--node--climate-dataset--field-key-limitations.html.twig * block--field-block--node--climate-dataset.html.twig * block--field-block--node.html.twig * block--field-block.html.twig * block--layout-builder.html.twig x block.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> <div class="block block-layout-builder block-field-blocknodeclimate-datasetfield-key-limitations"> <h2 class="mb-md-2">Key Limitations</h2> <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--climate-dataset---custom--field-key-limitations.html.twig * field--node--field-key-limitations---custom.html.twig * field--node--climate-dataset--field-key-limitations.html.twig * field--node--field-key-limitations--climate-dataset--default.html.twig * field--node--field-key-limitations--climate-dataset.html.twig * field--node--field-key-limitations.html.twig * field--node--climate-dataset.html.twig * field--field-key-limitations.html.twig x field--text-long.html.twig * field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--text-long.html.twig' --> <div class="clearfix text-formatted field field--name-field-key-limitations field--type-text-long field--label-visually_hidden"> <div class="field__label visually-hidden">Key Limitations</div> <div class="field__items"> <div class="field__item"><p>Raw monthly values are noisy; Must be smoothed</p> </div> <div class="field__item"><p>Tahiti values prior to 1935 should be used with appropriate caution.</p> </div> </div> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--text-long.html.twig' --> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> <!-- THEME DEBUG --> <!-- THEME HOOK: 'block' --> <!-- FILE NAME SUGGESTIONS: * block--field-block--field-expert-developer-guidance.html.twig * block--field-block--node--climate-dataset--field-expert-developer-guidance.html.twig * block--field-block--node--climate-dataset.html.twig * block--field-block--node.html.twig * block--field-block.html.twig * block--layout-builder.html.twig x block.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> <div class="block block-layout-builder block-field-blocknodeclimate-datasetfield-expert-developer-guidance"> <h2 class="mb-md-2">Expert Developer Guidance</h2> <!-- THEME DEBUG --> <!-- THEME HOOK: 'field' --> <!-- FILE NAME SUGGESTIONS: * field--climate-dataset---custom--field-expert-developer-guidance.html.twig * field--node--field-expert-developer-guidance---custom.html.twig * field--node--climate-dataset--field-expert-developer-guidance.html.twig * field--node--field-expert-developer-guidance--climate-dataset--default.html.twig * field--node--field-expert-developer-guidance--climate-dataset.html.twig * field--node--field-expert-developer-guidance.html.twig * field--node--climate-dataset.html.twig * field--field-expert-developer-guidance.html.twig x field--text-long.html.twig * field.html.twig --> <!-- BEGIN OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--text-long.html.twig' --> <div class="clearfix text-formatted field field--name-field-expert-developer-guidance field--type-text-long field--label-visually_hidden"> <div class="field__label visually-hidden">Expert Developer Guidance</div> <div class="field__item"><p>The following was contributed by Dr. Kevin Trenbeth, August, 2015:</p> <p class="WG1BodyText">The analysis of teleconnections has typically employed a linear perspective, which assumes a basic spatial pattern with varying amplitude and mirror image positive and negative polarities. In the Northern Hemisphere, one-point correlation maps can be used to illustrate the Pacific-North American (PNA) pattern and the NAO.  Teleconnections are best defined over a grid, but simple indices based on a few key station locations remain attractive, as the series can often be carried back in time long before complete gridded fields are available; the disadvantage is increased noise from the reduced spatial sampling. Generally it is desirable to normalize the values so that each location has equal variance in the index, and to retain the seasonal cycle, an annual mean standard deviation is often best.</p> <p class="WG1BodyText">For several indices, two stations at opposite poles in the centers of action are used in combination to define the time series and associated pattern.  Examples are the Southern Oscillation Index, which uses sea level pressures at Darwin, Australia and Tahiti in the South Pacific, and the North Atlantic Oscillation, which uses Lisbon, Portugal and Stykkisholmur/Reykjavik, Iceland.  The NAO is primarily a north-south dipole in sea level pressure characterised by simultaneous out-of-phase pressure and height anomalies between temperate and high latitudes over the Atlantic sector, and therefore corresponds to changes in the westerlies across the North Atlantic into Europe.</p> <p class="WG1BodyText">Each station can obviously be affected by local storms and other phenomena, such as the Madden-Julian Oscillation for the tropics, and therefore station-based indices contain noise.  If the index S = T<sub>N</sub> –D<sub>N</sub>, (for example, S=SOI, and D and T refer to Darwin and Tahiti, and the subscript N means they are normalized), then a measure of the noise is N = T<sub>N</sub> + D<sub>N</sub>.   The ratio of the variance of the signal and noise time series provides a metric of how useful such a simple index is.  Tracking both signal and noise can also help the user from being led astray. ##</p> </div> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/field/field--text-long.html.twig' --> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/block/block.html.twig' --> </main> </div> <!-- END OUTPUT from 'profiles/composer/unity-profile/themes/unity/templates/layout/layout--twocol-section.html.twig' --> Fri, 04 Nov 2011 16:34:00 +0000 ryanj 649 at https://climatedataguide.ucar.edu