Atmosphere Reanalyses
The term "re-analysis" is derived from the numerical analysis that is used in weather forecasts. The re-analysis data are calculated with models (similar to the ones used for weather prediction), that assimilate quality-assured monitoring data. The data contain global fields in different height levels of various parameters and are calculated over a long time period using all the appropriate observations. The aim of the re-analysis is to get a homogeneous data set, with high temporal and spatial resolution, that is suitable for the calculation of climatologies, for example.
The most important re-analysis products are:
American reanalyses of National Center for Environmental Prediction (NCEP):
- NCEP/NCAR Reanalysis
- NCEP/DOE AMIP-II Reanalysis
- NCEP NARR - North American Regional Reanalysis
- NCEP CFSR - Climate Forecast System Reanalysis
European re-analysis of European Centre for Medium-Range Weather Forecast (ECMWF):
- ERA40 (not recommended anymore)
- ERA Interim
- ERA5
Japanese re-analyses:
- JRA-25 (not recommended anymore)
- JRA-55
NASA Goddard Space Flight Center re-analysis:
A comprehensive collection of several reanalyses can be found on
Analyses
In the context of weatherforecasting, the data produced for 0 o'clock aretypically referred to as analysis. They are quickly available, but the quality is not as well as for the re-analyses.
- American predictions and analyses of GFS
- European predictions and analyses of ECMWF
Comparison of Reanalyses
| Name | Organization | Time period | Resolution | Data assi- milation method | Comments |
|---|---|---|---|---|---|
| JRA-25 | JMA/CRIEPI | 1979 – present | T106 L40, global | 3D-Var | Originally limited to 2004, then continued as JCDAS (real time operation) |
| ERA-15 | ECMWF | 1979 - 1993 | T106 L31, global | 3D-OI | Successor of FGGE. |
| ERA-40 | ECMWF | 09/1957 - 08/2002 | TL159 L60, global | 3D-Var | Successor of ERA-15 |
| ERA Interim | ECMWF | 1979 - present | T255 L60, global | 12h 4D-Var | Originally limited to 1989. Successor of ERA-40. |
| NCEP/NCAR Reanalysis R1 | NCEP/NCAR | 1948 - present | T62 L28, global | 3D-Var | is operated as CDAS. |
| NCEP/DOE R2 (NCEP-DOE AMIP-II reanalysis) | NCEP/DOE | 1979-present | T62 L28 | 3D-Var | is operated as CDAS. |
| NCEP NARR - North American Regional Reanalysis | NCEP | 1979 - present | 32km 29PL, North America | ||
| NCEP CFSR - Climate Forecast System Reanalysis | NCEP | 1979 - 2008 | T382 L64 | ||
| GEOS1 | NASA/DAO | 1980–1995 | 2° x 2.5° L20 | 3D-OI + IAU | |
| NASA MERRA | NASA | 1979 - present | 0.5°(lat) x 2/3° (lon) L72, global |