Reanalysis

Comprehensive weather and climate datasets, reanalyses assimilate a variety of observations of the atmosphere, land surface, and ocean into a forecast model to provide a dynamically consistent estimate of the climate state at each time step.

Below is the atmospheric reanalysis overview page, which summarizes the attributes of the major atmospheric reanalyses. This section also includes selected oceanic reanalyses, although an overview is not available yet.

To find a specific reanalysis, jump to the search box below or click your desired reanalysis from among the blue sub-category buttons.

To see only the reanalyses pages accompanied by in-depth commentary, select the "Datasets with guidance" button when using the search box.

Climate datasets

Has expert guidance
JRA-55 JRA-55

  • Years of record

  • to

Spanning 1958-present, JRA-55 is the longest third-generation reanalysis that uses the full observing system (in contrast, products like ERA-20C and NOAA 20CR assimilate a very limited set of observations while NCEP R1 uses an antiquated model and assimilation scheme).…

Main variables and Earth System components

Atmosphere Air Temperature Geopotential Height Precipitable water

    • Timestep

    • Sub-daily, Monthly

    • Collections

    • None
ERA-20C: ECMWF's atmospheric reanalysis of the 20th century (and comparisons with NOAA's 20CR) ERA-20C: ECMWF's atmospheric reanalysis of the 20th century (and comparisons with NOAA's 20CR)

  • Years of record

  • to

The ECMWF's first atmospheric reanalysis of the 20th Century, ERA-20C, provides a long, gridded dataset of many climate variables, spanning 1900-2010.  Observations assimilated include surface pressures from the International Surface Pressure Databank v3.2.6 and…

Main variables and Earth System components

Atmosphere Multiple variables
CERA-20C: ECMWF's Coupled Ocean-Atmosphere Reanalysis of the 20th Century CERA-20C: ECMWF's Coupled Ocean-Atmosphere Reanalysis of the 20th Century

  • Years of record

  • to

The CERA-20C is a global, coupled reanalysis spanning 1901-2010 with a focus on low-frequency climate variability.  Similar to ERA-20C, the surface observations assimilated include surface pressures from the International Surface Pressure Databank v3.2.6 and ICOADS v…

Main variables and Earth System components

Atmosphere Multiple variables Cryosphere Sea Ice Concentration Ocean

    • Timestep

    • Sub-daily, Daily, Monthly

    • Collections

    • None