Revision as of 20:08, 7 August 2022 by P.petrelli (talk | contribs)
(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)

The Japan Meteorological Agency (JMA) conducted JRA-55, the second Japanese global atmospheric reanalysis project. It covers 55 years, extending back to 1958, coinciding with the establishment of the global radiosonde observing system. Compared to its predecessor, JRA-25, JRA-55 is based on a new data assimilation and prediction system (DA) that improves many deficiencies found in the first Japanese reanalysis. These improvements have come about by implementing higher spatial resolution (TL319L60), a new radiation scheme, four-dimensional variational data assimilation (4D-Var) with Variational Bias Correction (VarBC) for satellite radiances, and introduction of greenhouse gases with time varying concentrations. The entire JRA-55 production was completed in 2013, and thereafter will be continued on a real time basis. (This information was obtained from the NCAR website http://rda.ucar.edu/datasets/ds628.0/)

The CREATE-IP project offers now a version of this dataset which comes already as netcdf, from now on we are going to download this version in the ua8 project (see below for details). We won't be updating anymore the RDA version available in rr7.



You need to register by filling the JRA-55 project application form to use this dataset. A copy of their agreement is available here as File:Application_JRA_Data_Access.pdf.

More information, the JRA55 user manuals for pressure and model levels and quality issues with the data are listed both in the JRA-55 project website and the NCAR Climate Data Guide and JRA-55 dataset webpages

To cite:

Japan Meteorological Agency/Japan (2013), JRA-55: Japanese 55-year Reanalysis, Daily 3-Hourly and 6-Hourly Data, https://doi.org/10.5065/D6HH6H41, Research Data Archive at the National Center for Atmospheric Research, Computational and Information Systems Laboratory, Boulder, Colo. (Updated monthly.) Accessed dd mmm yyyy.
  Please fill in the "Accessed" date with the day, month, and year (e.g. - 5 Aug 2011) you last accessed the data.


Known issues

29-01-2020 - Some tropical cyclones occurring over the Northeast Pacific and the North Atlantic from 1959 to 1987 were erroneously represented as anti-cyclonic vortices in the Japanese 55-year Reanalysis (JRA-55) dataset. A detailed report is available at the JRA-55 website:

  1. Issue with tropical cyclone analysis in JRA-55


JRA55 at NCI

CREATE-IP version:

This version is available in ua8 at


6 hourly data:  6hr/v20200612

variables: tas, uas, vas, ps, psl, zg (pressure levels)

monthly data:  mon/v20200612

variables: clt, evspsbl, hur, hus, pr, prw, ps, psl, rlds, rldscs, rlus, rlut, rlutcs, rsds, rsdscs, rsdt, rsus, rsuscs, rsut, rsutcs, sfcWind, ta, tas, tro3, ts, ua, uas, va, vas, zg  (3D variables are on pressure levels)

Discontinued rr7 version:

NB this hasn't been updated for a long time so we are not giving access to it anymore!!!

Data is located in

  • pressure levels: /g/data/rr7/JRA55/6hr/atmos/<varname>/v1/<filenames>
  • model levels: /g/data/rr7/JRA55/6hr/atmos/reg-tl319/<varname>/v1/<filenames>

Filenames are: _<mip>_JRA55_<grid>_<YYYYMMDDHH-YYYMMDDHH>.nc <grid> information is currently present only for model level data and it is "reg-tl319" <mip> is 6hrPlev and 6hrLev for pressure and model levels respectively

List of variables

Currently available variables on model levels are

  • ta - atmospheric temperature
  • ua - eastward wind component
  • va - northward wind component
  • hus - specific humidity
  • zg - geopotential
  • ps - surface air pressure

Currently available variables on pressure levels are

  • tas- surface atmospheric temperature
  • uas - surface eastward wind component
  • vas - surface northward wind component
  • hurs - surface relative humidity
  • huss - surface specific humidity
  • zg - geopotential
  • ps - surface air pressure
  • psl - air pressure at sea level
  • dptas - Near-Surface Dew Point Depression

Download & conversion process

We downloaded the model analysis level from the NCAR website and the pressure level data from the JMA Data Dissemination System


You can add comment on this collection directly here or on the dedicated Observational and Reanalysis Data page on NCI confluence For questions use the Climate Community confluence questions .