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
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

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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…

Main variables and Earth System components

Ocean SST - sea surface temperature

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Meridional Modes and their indices 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…

Main variables and Earth System components

Atmosphere Wind Ocean SST - sea surface temperature
Pacific Decadal Oscillation (PDO): Definition and Indices Pacific Decadal Oscillation (PDO): Definition and Indices

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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…

Main variables and Earth System components

Ocean SST - sea surface temperature
Multivariate ENSO Index Multivariate ENSO Index

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The Multivariate ENSO Index (MEI) is said to capture a more holistic representation of the atmospheric and oceanic anomalies that occur during ENSO events than do single-…

Main variables and Earth System components

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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)

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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. …

Main variables and Earth System components

Ocean SST - sea surface temperature
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
Amundsen Sea Low indices Amundsen Sea Low indices

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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…

Main variables and Earth System components

Atmosphere Sea Level Pressure
U.S. Climate Extremes Index (CEI) U.S. Climate Extremes Index (CEI)

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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. At…

Main variables and Earth System components

Atmosphere Air Temperature Maximum Air Temperature Minimum Air Temperature Precipitation Wind Land Drought
Atlantic Multi-decadal Oscillation (AMO) Atlantic Multi-decadal Oscillation (AMO) and Atlantic Multidecadal Variability (AMV)

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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…

Main variables and Earth System components

Ocean SST - sea surface temperature
MJO: Madden-Julian Oscillation Diagnostics MJO: Madden-Julian Oscillation Diagnostics

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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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