Online ISSN : 1349-6476
ISSN-L : 1349-6476
Preliminary Results of the JRA-55C, an Atmospheric Reanalysis Assimilating Conventional Observations Only
Chiaki KobayashiHirokazu EndoYukinari OtaShinya KobayashiHirokatsu OnodaYayoi HaradaKazutoshi OnogiHirotaka Kamahori
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Supplementary material

2014 Volume 10 Pages 78-82


As a subset of the Japanese 55-year Reanalysis (JRA-55) project, the Meteorological Research Institute of the Japan Meteorological Agency is conducting a global atmospheric reanalysis that assimilates only conventional surface and upper air observations, with no use of satellite observations, using the same data assimilation system as the JRA-55. The project, named the JRA-55 Conventional (JRA-55C), aims to produce a more homogeneous dataset over a long period, unaffected by changes in historical satellite observing systems. The dataset is intended to be suitable for studies of climate change or multi-decadal variability. The climatological properties deduced from the early results of the JRA-55C are similar to those of the JRA-55 in the troposphere and lower stratosphere, except for high southern latitudes. On the basis of forecast skill, the quality of the JRA-55C is inferior to that of the JRA-55, but the JRA-55C has better temporal homogeneity than the JRA-55. The skill of the latter changes during the JRA-55 period. We have completed 85% of the entire JRA-55C calculation as of February 2014. We expect that the JRA-55C will contribute to a much better understanding of the impact of changes in observing systems on climate trends and variability estimated from the JRA-55.

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© 2014 by the Meteorological Society of Japan
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