JRA-55: Japanese 55-year Reanalysis, Near Real-Time Data -- Monthly Means and Variances

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. Specific early results of quality assessment of JRA-55 indicate that a large temperature bias in the lower stratosphere has been significantly reduced compared to JRA-25 through a combination of the new radiation scheme and application of VarBC (which also reduces unrealistic temperature variations). In addition, a dry land surface anomaly in the Amazon basin has been mitigated, and overall forecast scores are much improved over JRA-25. Most of the observational data employed in JRA-55 are those used in JRA-25. Additionally, newly reprocessed METEOSAT and GMS data were supplied by EUMETSAT and MSC/JMA respectively. Snow depth data over the United States, Russia and Mongolia were supplied by UCAR, RIHMI and IMH respectively.

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Temporal Range

  • Begin:  2020-01-01T0000+00
    End:  2024-02-01T0000+00

Keywords

Resource Type dataset
Temporal Range Begin 2020-01-01T0000+00
Temporal Range End 2024-02-01T0000+00
Temporal Resolution N/A
Bounding Box North Lat 90.0
Bounding Box South Lat -90.0
Bounding Box West Long -180.0
Bounding Box East Long 180.0
Spatial Representation grid
Spatial Resolution 1.25 degree
2.5 degree
Related Links

Related Resource #1 : JRA-55: Japanese 55-year Reanalysis

Related Resource #2 : Description of JRA-55 at the NCAR Climate Data Guide

Related Resource #3 : JRA-55 Quality Issues
Additional Information N/A
Resource Format WMO GRIB1
Standardized Resource Format GRIB
Asset Size 70746.73 MB
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(The complete JMA and NCAR agreement for JRA-55 may be viewed via the Documentation tab.)
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Software Implementation Language N/A

Resource Support Name N/A
Resource Support Email datahelp@ucar.edu
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Distributor NSF NCAR Geoscience Data Exchange
Metadata Contact Name N/A
Metadata Contact Email datahelp@ucar.edu
Metadata Contact Organization NSF NCAR Geoscience Data Exchange

Author Japan Meteorological Agency, Japan
Publisher NSF National Center for Atmospheric Research
Publication Date 2020-09-18
Digital Object Identifier (DOI) https://doi.org/10.5065/7WR1-VB85
Alternate Identifier d628009
Resource Version N/A
Topic Category climatologyMeteorologyAtmosphere
Progress onGoing
Metadata Date 2025-10-09T01:28:03Z
Metadata Record Identifier edu.ucar.gdex::d628009
Metadata Language eng; USA
Suggested Citation Japan Meteorological Agency, Japan. (2020). JRA-55: Japanese 55-year Reanalysis, Near Real-Time Data -- Monthly Means and Variances. NSF National Center for Atmospheric Research. https://doi.org/10.5065/7WR1-VB85. Accessed 31 October 2025.

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