NCAR Climate Data Guide Content with Tag: Climate Indices

AMO index timeseries (contributed by R. Zhang)
Atlantic Multi-decadal Oscillation (AMO)
Years of Record: 1856/01 to 2016/07
The Atlantic Multi-decadal Oscillation (AMO) has been identified as a coherent mode of natural variability occurring in the North Atlantic Ocean with an estimated period of 60-80 years. It is based upon the average anomalies of sea surface temperatures (SST) in the North Atlantic basin, typically...
Main variables and Earth System components:
Formats: netCDF | ascii Timestep: Monthly Domain: Atlantic Ocean, NH - Northern Hemisphere
Climate Data Guide Image: CRU sc-PDSI
CRU sc-PDSI (self-calibrating PDSI) over Europe & North America
Years of Record: 1901/01 to 2002/12
Maps of the monthly self-calibrating Palmer drought severity index (SCPDSI) have been calculated for the period 1901–2002 for the contiguous United States (20°–50°N and 130°–60°W) and Europe (35°–70°N, 10°W–60°E) with a spatial resolution of 0.5° × 0.5°
Main variables and Earth System components:
Formats: ascii Timestep: Monthly Domain: Europe, North America
map indicating tree-ring chronologies used to construct the NADA (courtesey Ed Cook)
Drought atlases from tree rings
Years of Record: 0000/01 to 2005/12
Tree-ring drought atlases provide a paleoclimate analog to modern drought indices, most commonly the Palmer Drought Severity Index (PDSI).  Produced on a regular lat-lon grid for regions such as North America, Europe, and Australia, these centuries-long datasets are convenient for comparisons...
Main variables and Earth System components:
Formats: netCDF | ascii Timestep: Annual Domain: North America
NCAR Climate Data Guide Image using GHCNDEX data.
GHCNDEX: Gridded Temperature and Precipitation Climate Extremes Indices (CLIMDEX data)
Years of Record: 1951/01 to 2014/02
GHCNDEX provides gridded, station-based indices of temperature- and precipitation- related climate extremes. It is intended for climate change detection and attribution studies, climate model evaluation, and operational monitoring of extreme climatic events. Twenty-six indices, including daily...
Main variables and Earth System components:
Formats: netCDF | ascii Timestep: Monthly Domain: Global
NCAR Climate Data Guide Image using HadEX2 data.
HadEX2: Gridded Temperature and Precipitation Climate Extremes Indices (CLIMDEX data)
Years of Record: 1901/01 to 2010/12
HadEX2 provides gridded, station-based indices of temperature- and precipitation- related climate extremes. It is intended for climate change detection and attribution studies and climate model evaluation. Twenty-nine indices, including daily maximum and minimum temperatures, number of frost days,...
Main variables and Earth System components:
Formats: netCDF | ascii Timestep: Monthly,Annual Domain: Global
Hurrell North Atlantic Oscillation (NAO) Index (station-based)
Years of Record: 1865/01 to 2017/06
The winter (December thru March) station-based index of the NAO is based on the difference of normalized sea level pressure (SLP) between Lisbon, Portugal and Stykkisholmur/Reykjavik, Iceland since 1864. Positive values of the NAO index are typically associated with stronger-than-average...
Main variables and Earth System components:
Formats: ascii Timestep: Monthly,Seasonal,Annual Domain: Atlantic Ocean
Hurrell wintertime SLP-based Northern Annular Mode (NAM) Index
Years of Record: 1899/01 to 2016/03
The NAM (or Arctic Oscillation) is defined as the first EOF of NH (20°-90°N) winter SLP data. It explains 23% of the extended winter mean (December-March) variance, and it is clearly dominated by the NAO structure in the Atlantic sector. Although there are some subtle differences from the NAO...
Main variables and Earth System components:
Formats: ascii Timestep: Seasonal Domain: Atlantic Ocean, NH - Northern Hemisphere, Pacific Ocean
Marshall Southern Annular Mode (SAM) Index (Station-based)
Years of Record: 1957/01 to 2015/09
The station-based index of the Southern Annular Mode (SAM) is based on the zonal pressure difference between the latitudes of 40S and 65S.  As such, the SAM index measures a "see-saw" of atmospheric mass between the middle and high latitudes of the Southern Hemisphere.  Positive values of...
Main variables and Earth System components:
Formats: ascii Domain: Antarctic, SH - Southern Hemisphere, Southern Ocean
See Expert Guidance by Marshall, Gareth
MJO: Madden-Julian Oscillation Diagnostics
"The Madden–Julian oscillation (MJO) is the largest element of the intraseasonal (30–90 days) variability in the tropical atmosphere. It is a large-scale coupling between atmospheric circulation and tropical deep convection.[1][2] Rather than being a standing pattern (like ENSO) it is a traveling...
Multivariate ENSO Index
Years of Record: 1950/01 to 2013/01
The Multivariate ENSO Index (MEI) on the six main observed variables over the tropical Pacific. These six variables are: sea-level pressure (P), zonal (U) and meridional (V) components of the surface wind, sea surface temperature (S), surface air temperature (A), and total cloudiness fraction of...
Formats: ascii Timestep: Monthly Domain: Pacific Ocean
The Oceanic Nino Index (ONI), a variant of the Nino 3.4 index
Nino SST Indices (Nino 1+2, 3, 3.4, 4; ONI and TNI)
Years of Record: 1870/01 to 2015/11
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...
Main variables and Earth System components:
Timestep: Monthly Domain: Pacific Ocean, Tropics
See Expert Guidance by Trenberth, Kevin
Climate Data Guide Image: ThreadEx
NOAA ThreadEx Long-term Station Extremes for America
Years of Record: 1870/01 to 2011/12
ThreadEx is a data set of extreme daily temperature and precipitation values for 270 locations in the United States. For each day of the year at each station, ThreadEx provides the top 3 record high and low daily maximum temperatures, the top 3 record high and low daily minimum temperatures, the...
Main variables and Earth System components:
Formats: ascii Timestep: Daily Domain: North America
North Pacific (NP) Index by Trenberth and Hurrell; monthly and winter
Years of Record: 1899/01 to 2017/08
The North Pacific Index (NP index or NPI) is the area-weighted sea level pressure over the region 30°N-65°N, 160°E-140°W. The NP index is defined to measure interannual to decadal variations in the atmospheric circulation. The dominant atmosphere-ocean relation in the North Pacific is one where...
Main variables and Earth System components:
Formats: ascii Timestep: Monthly,Seasonal Domain: NH - Northern Hemisphere, Pacific Ocean
Overview: Climate Indices
A climate index is a simple diagnostic quantity that is used to characterize an aspect of a geophysical system such as a circulation pattern. A variety of methods have been used to derive assorted indices. Classically, selected station, grid point or regional average data have been used (eg.,...
Main variables and Earth System components:
spatial pattern of the PDO (contributed by C. Deser)
Pacific Decadal Oscillation (PDO): Definition and Indices
Years of Record: 1900/01 to 2015/12
The Pacific Decadal Oscillation (PDO) is defined by the leading pattern (EOF) of sea surface temperature (SST) anomalies in the North Pacific basin (typically, polewards of 20°N).  The SST anomalies are obtained by removing both the climatological annual cycle and the global-mean SST anomaly...
Main variables and Earth System components:
Formats: ascii Timestep: Monthly Domain: Pacific Ocean
See Expert Guidance by Deser, Clara | See Expert Guidance by Trenberth, Kevin
Palmer Drought Severity Index (PDSI)
The Palmer Drought Severity Index (PDSI) uses readily available temperature and precipitation data to estimate relative dryness. It is a standardized index that spans -10 (dry) to +10 (wet). It has been reasonably successful at quantifying long-term drought. As it uses temperature data and a...
Main variables and Earth System components:
Formats: netCDF | ascii | binary Timestep: Monthly Domain: Global
Climate Data Guide Image: QBO
QBO: Quasi-Biennial Oscillation
Years of Record: 1953/01 to 2012/09
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...
Main variables and Earth System components:
Formats: ascii Timestep: Monthly Domain: Tropics
Southern Oscillation Indices: Signal, Noise and Tahiti/Darwin SLP (SOI)
Years of Record: 1866/01 to 2016/01
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...
Main variables and Earth System components:
Formats: netCDF | ascii Timestep: Monthly Domain: Australia, Pacific Ocean, Tropics
See Expert Guidance by Trenberth, Kevin
Standardized Precipitation Evapotranspiration Index (SPEI)
Years of Record: 1901/01 to 2014/03
The Standardized Precipitation Evapotranspiration Index (SPEI) is an extension of the widely used Standardized Precipitation Index (SPI). The SPEI is designed to take into account both precipitation and potential evapotranspiration (PET) in determining drought. Thus, unlike the SPI, the SPEI...
Formats: netCDF | ascii Timestep: Monthly,Seasonal,Annual Domain: Global
See Expert Guidance by Vicente-Serrano, Sergio M.
6-month SPI through January, 2014 capturing drought in California and heavy rains in the Front range of Colorado. Retrieved on 31 January 2014 at http://www.hprcc.unl.edu/maps/current/index.php?action=update_daterange&daterange=6m
Standardized Precipitation Index (SPI)
Years of Record: 1949/01 to 2012/12
The Standardized Precipitation Index (SPI) is a widely used index to characterize meteorological drought on a range of timescales. On short timescales, the SPI is closely related to soil moisture, while at longer timescales, the SPI can be related to groundwater and reservoir storage. The SPI can...
Main variables and Earth System components:
Timestep: Monthly
NOAA CEI
U.S. Climate Extremes Index (CEI)
Years of Record: 1910/01 to 2012/12
The CEI was first presented in 1995 as a framework for quantifying observed changes in climate within the contiguous United States. The index is based on an aggregate set of conventional climate extreme indicators which now includes extremes in land- falling tropical storm and hurricane wind...
Main variables and Earth System components:
Formats: ascii Timestep: Monthly,Seasonal,Annual Domain: North America
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