Atmospheric Reanalysis
“Climate reanalyses combine past observations with models to generate consistent time series of multiple climate variables. Reanalyses are among the most-used datasets in the geophysical sciences. They provide a comprehensive description of the observed climate as it has evolved during recent decades, on 3D grids at sub-daily intervals.” (Copernicus)
Global reanalyses are produced by major Numerical Weather Prediction centers and they are under continuous development. This wiki page focuses on some of the most commonly used current-generation reanalysis products: ERA5, MERRA2, JRA-3Q, and NCEP.
| Source | Name and access link | Temporal coverage | Horizontal resolution | Available format | Documentation/further information |
|---|---|---|---|---|---|
| European Centre for Medium-Range Weather Forecast (ECMWF) | ERA5 | hourly, daily and monthly (1940/01 - present, some variables start later) | 0.25° x 0.25° | GRIB NetCDF | ERA5 documentation |
| Japanese Meteorological Agency | JRA-3Q | 6-hourly, monthly (also hourly or daily for some variables) (1947/09 - present) | 40 km | GRIB | JRA-3Q documentation |
| NASA Goddard Space Flight Center re-analysis | MERRA 2 | hourly, 3-hourly, 6-hourly, daily and monthly values (1980/01 - present) | 0.5° x 0.625° | NetCDF | MERRA documentation |
| National Center for Environmental Prediction (NCEP) | NCEP/NCAR Reanalysis 1 | 6-hourly, daily and monthly values (1948/01 - present) | 2.5° x 2.5° | NetCDF | Kalnay et al (1996) |
Note that there are more, including regional reanalysis products that may be more suitable for regional studies (e.g., COSMO and CERRA for Europe, NARR for North America, EARS for East Asia, CARRA for the Arctic).