Climate Indices
Climate indices are simple diagnostic quantities that are used to characterize an aspect of a geophysical system such as a circulation pattern. They track droughts, ENSO events, wind patterns, internal modes of climate variability, and extreme events like wildfires and heatwaves. Climate indices play a key role in climate monitoring and prediction. The climate index overview page summarizes the philosophy of climate indices.
To find a specific climate index, jump to the search box below or click your desired index from among the blue sub-category buttons.
To see only the indices with in-depth commentary, select the "Datasets with guidance" button when using the search box.
Dataset Overviews
Climate datasets
![Southern Hemisphere westerly jet strength and position Southern Hemisphere westerly jet strength and position](/sites/default/files/styles/medium/public/2022-03/u850_clim_SH_ann.png?itok=DkId6fWm)
Years of record
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The dynamics of the Southern Hemisphere westerly jet are described in terms of two indices, jet strength and jet latitude. Here, these indices are defined using the…
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Formats
- ascii
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Timestep
- Seasonal, Annual
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Collections
- N/A
Experts contributing reviews
- Bracegirdle, Thomas J.
![MJO: Madden-Julian Oscillation Diagnostics MJO: Madden-Julian Oscillation Diagnostics](/sites/default/files/styles/medium/public/2022-03/teaser_images_613.png?itok=ecXka0uX)
Years of record
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"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…
Main variables and Earth System components
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Formats
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Timestep
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Domain
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Collections
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Experts contributing reviews
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![NP Index](/sites/default/files/styles/medium/public/2024-04/npindex.teaser_0.gif?itok=oB1gVbUA)
Years of record
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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…
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Formats
- ascii
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Timestep
- Monthly, Seasonal
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Collections
- Climate Analysis Section (CAS) Data Catalog
Experts contributing reviews
- Hurrell, James | Phillips, Adam
![Asymmetry and Diversity in the pattern, amplitude and duration of El Niño and La Niña Asymmetry and Diversity in the pattern, amplitude and duration of El Niño and La Niña](/sites/default/files/styles/medium/public/2022-03/Santoso-snippet.png?itok=FFNoG7X6)
Years of record
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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…
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Formats
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Timestep
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Domain
- Tropics
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Collections
- N/A
Experts contributing reviews
- Santoso, Agus
![Marshall Southern Annular Mode (SAM) Index (Station-based) Marshall Southern Annular Mode (SAM) Index (Station-based)](/sites/default/files/styles/medium/public/2022-03/Marshall-SAM-F2.png?itok=wnSHfVmE)
Years of record
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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…
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Formats
- ascii
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Timestep
- N/A
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Collections
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Experts contributing reviews
- Marshall, Gareth
![Atlantic Multi-decadal Oscillation (AMO) Atlantic Multi-decadal Oscillation (AMO)](/sites/default/files/styles/medium/public/2022-03/AMOindex-Zhang.png?itok=A0P62TAr)
Years of record
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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…
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Timestep
- Monthly, Decadal
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Collections
- Climate Analysis Section (CAS) Data Catalog
Experts contributing reviews
- Trenberth, Kevin | Zhang, Rong
![Overview: Climate Indices Overview: Climate Indices](/sites/default/files/styles/medium/public/2022-03/oni.monthly.smoo_stro_0.png?itok=sZjCFl2r)
Years of record
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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…
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Formats
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Timestep
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Domain
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Collections
- Overview / Comparison page
Experts contributing reviews
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![NAO DJFM Station-based Index](/sites/default/files/styles/medium/public/2023-07/naots2_sm.gif?itok=bh4wPOF2)
Years of record
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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…
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Formats
- ascii
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Timestep
- Monthly, Seasonal, Annual
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Domain
- Atlantic Ocean
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Collections
- Climate Analysis Section (CAS) Data Catalog
Experts contributing reviews
- Hurrell, James | Phillips, Adam
![QBO: Quasi-Biennial Oscillation QBO: Quasi-Biennial Oscillation](/sites/default/files/styles/medium/public/2022-03/teaser_images_614.png?itok=CddHYHec)
Years of record
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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…
Experts contributing reviews
- N/A
![NAM Spatial Pattern (DJFM)](/sites/default/files/styles/medium/public/2024-04/nam_sm.png?itok=4_KjQ9ml)
Years of record
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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…
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Formats
- ascii
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Timestep
- Seasonal
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Collections
- N/A
Experts contributing reviews
- Phillips, Adam
![timeseries of signal and noise in the SOI](/sites/default/files/styles/medium/public/2023-09/soi3.gif?itok=jYDJ17xv)
Years of record
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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…
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Timestep
- Monthly
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Domain
- Australia, Pacific Ocean, Tropics
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Collections
- Climate Analysis Section (CAS) Data Catalog
Experts contributing reviews
- Trenberth, Kevin
![Amundsen Sea Low indices Amundsen Sea Low indices](/sites/default/files/styles/medium/public/2022-03/Hosking1-asl_index-v2_region.png?itok=Pddn85w4)
Years of record
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The Amundsen Sea Low (ASL) is a climatological low pressure center located over the extreme southern Pacific Ocean, off the coast of West Antarctica. Atmospheric…
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Timestep
- Monthly, Seasonal, Annual
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Collections
- N/A
Experts contributing reviews
- Hosking, Scott
![Pacific Decadal Oscillation (PDO): Definition and Indices Pacific Decadal Oscillation (PDO): Definition and Indices](/sites/default/files/styles/medium/public/2022-03/PDO-pattern.png?itok=tGsYIU7B)
Years of record
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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…
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Formats
- ascii
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Timestep
- Monthly
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Domain
- Pacific Ocean
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Collections
- N/A
Experts contributing reviews
- Deser, Clara | Trenberth, Kevin
![Nino SST Indices (Nino 1+2, 3, 3.4, 4; ONI and TNI) Nino SST Indices (Nino 1+2, 3, 3.4, 4; ONI and TNI)](/sites/default/files/styles/medium/public/2022-03/oni.monthly.smoo_stro.png?itok=HR_SsTzH)
Years of record
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There are several indices used to monitor the tropical Pacific, all of which are based on sea surface temperature (SST) anomalies averaged across a given region. …
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Formats
- ascii
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Timestep
- Monthly
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Domain
- Pacific Ocean, Tropics
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Collections
- Climate Analysis Section (CAS) Data Catalog
Experts contributing reviews
- Trenberth, Kevin