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
Hurrell North Atlantic Oscillation (NAO) Index (PC-based)
Years of record
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The principal component (PC)-based indices of the North Atlantic Oscillation (NAO) are the time series of the leading Empirical Orthogonal Function (EOF) of SLP anomalies…
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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
Hurrell North Atlantic Oscillation (NAO) Index (station-based)
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
Atlantic Multi-decadal Oscillation (AMO) and Atlantic Multidecadal Variability (AMV)
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
Hurrell wintertime SLP-based Northern Annular Mode (NAM) Index
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
Southern Oscillation Indices: Signal, Noise and Tahiti/Darwin SLP (SOI)
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
Overview: Climate Indices
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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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Meridional Modes and their indices
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In each of the world’s tropical ocean basins, year-to-year climate variability is primarily governed by fluctuations in the zonal sea surface temperature (SST) gradient and…
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Formats
- N/A
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Timestep
- N/A
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Domain
- Atlantic Ocean, Pacific Ocean
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Collections
- N/A
Experts contributing reviews
- Amaya, Dillon