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JRA projectJRA-55JRA-55 Atlas

Production method

Calculation Making figure References

  • The figures of JRA-55 ATLAS were calculated using the Japanese 55-year reanalysis (JRA-55, Kobayashi et al. 2015).
  • The climatology (normal value) was calculated by 30-year data from 1981 to 2010, but a part of figures were calculated with data from 1958, a beginning of JRA-55.
  • Climatologies were calculated for annual, seasonally and monthly. Seasons are divided to four as DEC-JAN-FEB (DJF), MAR-APR-MAY (MAM), JUN-JUL-AUG (JJA) and SEP-OCT-NOV (SON).
  • Calculations were performed with 6-hourly analysis and forecast data of JRA-55. Analysis data was prior to use if required elements were contained in both analysis and forecast.
  • Although JRA-55 provides the following two different horizontal grids the former was used with priority.
    • 1: Model grid (TL319 reduced Gaussian grid, corresponding approximately 55-km horizontal resolution)
    • 2: 1.25-degree latitude/longitude grid
    The latter was used in case that required elements were not contained in the former.
  • Numerical data file with CSV format has 1.25 degree latitude/longitude grid, even if the figure was calculated with model grid data.
  • The detailed explanation of figure is shown in a pop-up window when you click a button "explanation" located under the figure.
  • The figure commentaries provide information on the data used. See JRA-55 Manual for details of the data.


  • Grid Analysis and Display System (GrADS) version 2.1.a2 was used to draw figure.
  • Color palette of "color 1" is based on rainbow color, while "color 2" is based on the Brewer color which is a fruits of study by Dr. Cynthia A. Brewer, a professor of geography at the Pennsylvania state university.