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
![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
- to
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…
-
Formats
- ascii
-
Timestep
- Monthly
-
Domain
- Pacific Ocean
-
Collections
- N/A
Experts contributing reviews
- Deser, Clara | Trenberth, Kevin
![Meridional Modes and their indices Meridional Modes and their indices](/sites/default/files/styles/medium/public/2022-03/NPMM_schematic.png?itok=_YAO699f)
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) gradient and…
-
Formats
- N/A
-
Timestep
- N/A
-
Domain
- Atlantic Ocean, Pacific Ocean
-
Collections
- N/A
Experts contributing reviews
- Amaya, Dillon
![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
- to
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…
-
Timestep
- Monthly, Decadal
-
Collections
- Climate Analysis Section (CAS) Data Catalog
Experts contributing reviews
- Trenberth, Kevin | Zhang, Rong
![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
- to
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. …
-
Formats
- ascii
-
Timestep
- Monthly
-
Domain
- Pacific Ocean, Tropics
-
Collections
- Climate Analysis Section (CAS) Data Catalog
Experts contributing reviews
- Trenberth, Kevin
![NP Index](/sites/default/files/styles/medium/public/2024-04/npindex.teaser_0.gif?itok=oB1gVbUA)
Years of record
- to
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…
-
Formats
- ascii
-
Timestep
- Monthly, Seasonal
-
Collections
- Climate Analysis Section (CAS) Data Catalog
Experts contributing reviews
- Hurrell, James | 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
- 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 mean SLP at…
-
Timestep
- Monthly
-
Domain
- Australia, Pacific Ocean, Tropics
-
Collections
- Climate Analysis Section (CAS) Data Catalog
Experts contributing reviews
- Trenberth, Kevin
![NAM Spatial Pattern (DJFM)](/sites/default/files/styles/medium/public/2024-04/nam_sm.png?itok=4_KjQ9ml)
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) variance, and it…
-
Formats
- ascii
-
Timestep
- Seasonal
-
Collections
- N/A
Experts contributing reviews
- Phillips, Adam
![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
- 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. Atmospheric…
-
Timestep
- Monthly, Seasonal, Annual
-
Collections
- N/A
Experts contributing reviews
- Hosking, Scott
![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
- 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 methods have been…
-
Formats
- N/A
-
Timestep
- N/A
-
Domain
- N/A
-
Collections
- Overview / Comparison page
Experts contributing reviews
- N/A