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
Marshall Southern Annular Mode (SAM) Index (Station-based)
Years of record
- to
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…
-
Formats
- ascii
-
Timestep
- N/A
-
Collections
- N/A
Experts contributing reviews
- Marshall, Gareth
Southern Hemisphere westerly jet strength and position
Years of record
- to
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…
-
Formats
- ascii
-
Timestep
- Seasonal, Annual
-
Collections
- N/A
Experts contributing reviews
- Bracegirdle, Thomas J.
Standardized Precipitation Evapotranspiration Index (SPEI)
Years of record
- to
The Standardized Precipitation Evapotranspiration Index (SPEI) is an extension of the widely used Standardized Precipitation Index (SPI). The SPEI is designed to…
Main variables and Earth System components
N/AExperts contributing reviews
- Vicente-Serrano, Sergio M.
Drought atlases from tree rings
Years of record
- to
Tree-ring drought atlases provide a paleoclimate analog to modern drought indices, most commonly the Palmer Drought Severity Index (PDSI). Produced on a regular…
-
Timestep
- Annual
-
Domain
- North America
-
Collections
- N/A
Experts contributing reviews
- Cook, Edward
Standardized Precipitation Index (SPI)
Years of record
- to
The Standardized Precipitation Index (SPI) is a widely used index to characterize meteorological drought on a range of timescales. On short timescales, the SPI…
-
Formats
- N/A
-
Timestep
- Monthly
-
Domain
- N/A
-
Collections
- N/A
Experts contributing reviews
- Keyantash, John
Nino SST Indices (Nino 1+2, 3, 3.4, 4; ONI and TNI)
Years of record
- to
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…
-
Formats
- ascii
-
Timestep
- Monthly
-
Domain
- Pacific Ocean, Tropics
-
Collections
- Climate Analysis Section (CAS) Data Catalog
Experts contributing reviews
- Trenberth, Kevin
Meridional Modes and their indices
Years of record
- N/A
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)…
-
Formats
- N/A
-
Timestep
- N/A
-
Domain
- Atlantic Ocean, Pacific Ocean
-
Collections
- N/A
Experts contributing reviews
- Amaya, Dillon
Southern Oscillation Indices: Signal, Noise and Tahiti/Darwin SLP (SOI)
Years of record
- to
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…
-
Timestep
- Monthly
-
Domain
- Australia, Pacific Ocean, Tropics
-
Collections
- Climate Analysis Section (CAS) Data Catalog
Experts contributing reviews
- Trenberth, Kevin
Overview: Climate Indices
Years of record
- N/A
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…
-
Formats
- N/A
-
Timestep
- N/A
-
Domain
- N/A
-
Collections
- Overview / Comparison page
Experts contributing reviews
- N/A
NSIDC Sea Ice Index
Years of record
- to
The NSIDC Sea Ice Index is a suite of easy-to-use sea ice analyses to track changes in Arctic and Antarctic sea ice. The product is produced and supported by the…
Experts contributing reviews
- Meier, Walter
Amundsen Sea Low indices
Years of record
- to
The Amundsen Sea Low (ASL) is a climatological low pressure center located over the extreme southern Pacific Ocean, off the coast of West Antarctica. …
-
Timestep
- Monthly, Seasonal, Annual
-
Collections
- N/A
Experts contributing reviews
- Hosking, Scott
Hurrell wintertime SLP-based Northern Annular Mode (NAM) Index
Years of record
- to
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)…
-
Formats
- ascii
-
Timestep
- Seasonal
-
Collections
- N/A
Experts contributing reviews
- Phillips, Adam
U.S. Climate Extremes Index (CEI)
Years of record
- to
The U.S. Climate Extremes Index (CEI) was first presented in 1995 as a framework for quantifying observed changes in climate within the contiguous United States…
Main variables and Earth System components
Atmosphere Air Temperature Maximum Air Temperature Minimum Air Temperature Precipitation Wind Land Drought-
Formats
- ascii
-
Timestep
- Monthly, Seasonal, Annual
-
Domain
- North America
-
Collections
- N/A
Experts contributing reviews
- Gleason, Karin
HadEX2: Gridded Temperature and Precipitation Climate Extremes Indices (CLIMDEX data)
Years of record
- to
HadEX2 provides gridded, station-based indices of temperature- and precipitation- related climate extremes. It is intended for climate change detection and…
Main variables and Earth System components
Atmosphere Maximum Air Temperature Minimum Air Temperature Land Freeze/ThawExperts contributing reviews
- N/A
GHCNDEX: Gridded Temperature and Precipitation Climate Extremes Indices (CLIMDEX data)
Years of record
- to
GHCNDEX provides gridded, station-based indices of temperature- and precipitation- related climate extremes. It is intended for climate change detection and…
Main variables and Earth System components
Atmosphere Maximum Air Temperature Minimum Air Temperature Land Freeze/ThawExperts contributing reviews
- N/A
Asymmetry and Diversity in the pattern, amplitude and duration of El Niño and La Niña
Years of record
- N/A
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…
-
Formats
- N/A
-
Timestep
- N/A
-
Domain
- Tropics
-
Collections
- N/A
Experts contributing reviews
- Santoso, Agus