JRA-55: Japanese 55-year Reanalysis, Near Real-Time Data

Important Notice: Update of JRA-55 data will terminate at the end of January 2024. Please use Near Real-Time Japanese Reanalysis for Three Quarters of a Century (JRA-3Q) [rda.ucar.edu/datasets/ds640.1/] at that time. 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.