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

Has expert guidance
timeseries of signal and noise in the SOI Southern Oscillation Indices: Signal, Noise and Tahiti/Darwin SLP (SOI)

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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…

Main variables and Earth System components

Atmosphere Sea Level Pressure
Palmer Drought Severity Index (PDSI) Palmer Drought Severity Index (PDSI)

  • Years of record

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The Palmer Drought Severity Index (PDSI) uses readily available temperature and precipitation data to estimate relative dryness. It is a standardized index that generally…

Main variables and Earth System components

Land Drought
Standardized Precipitation Evapotranspiration Index (SPEI) Standardized Precipitation Evapotranspiration Index (SPEI)

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The Standardized Precipitation Evapotranspiration Index (SPEI) is an extension of the widely used Standardized Precipitation Index (SPI). The SPEI is designed to take into…

Main variables and Earth System components

N/A

    • Timestep

    • Monthly, Seasonal, Annual

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Standardized Precipitation Index (SPI) Standardized Precipitation Index (SPI)

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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…

Main variables and Earth System components

Atmosphere Precipitation Land Drought

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    • Timestep

    • Monthly

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FWI p95 in ERAI and CESM1-LE (contributed by Danielle Touma) Canadian Forest Fire Weather Index (FWI)

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Fire weather indices are used to quantify the meteorological conditions that can lead to fire ignition and spread. They are used to communicate fire danger levels to…

Main variables and Earth System components

Atmosphere

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    • Timestep

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Drought atlases from tree rings Drought atlases from tree rings

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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-…

Main variables and Earth System components

Land Drought