JCDAS data corrections (2005.1-2007.10)

Corrected JCDAS data are available now.

Several bugs were found in JCDAS dataset from Jan.2005 to Oct.2007.
The following bugs are included in the current version of JCDAS for public.

• Bias correction coefficients for sounder (AMSU-A,B) were not appropriate.

It caused overestimation of precipitation since 2005 and of negative temperature bias in the tropopause.


• Drifting buoys of low quality were unexpectedly assimilated in the SST analysis

from middle of November 2005 to middle of January 2006.


• Reconstructed wind profile data surrounding tropical cyclones (TCR) were missed

from March to October 2006 in global and missed from March 2006 to October 2007 in western hemisphere.


• AMV data of MTSAT-1R were not used from July 2005 to September 2006.

The bugs have been fixed and the data assimilation cycle for the period was carried out again.

JCDAS data including the bugs were replaced by the newly re-calculated data on 25th February, 2008.

Thank you for your attention.

• Time series of global averaged precipitation is shown.

Black line is of JRA-25 and current JCDAS, red line is of re-calculated JCDAS.



• Pressure-time distributions of monthly averaged global temperature difference (recalculated JCDAS minus current JCDAS) are shown.

The problem of the bias correction was fixed in May 2007.

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