The monthly mean surface air temperature at 2 m from the NCEP/DOE, ERA-interim and JRA-25 reanalysis data-sets were respectively compared with those observed value at meteorological stations in the east of Qinghai-Xizang Plateau area from 1989 to 2009. The results show that the reanalysis air temperature is higher credibility in summer than in winter, the NCEP/DOE reanalysis data is systematically smaller than the observation, while JRA-25 is systematically higher. The datasets of ERA-interim, JRA-25 and the observation value all show similar warming trends in the east of Qinghai-Xizang Plateau from 1989 to 2009, while NCEP/DOE shows a cooling trend instead. When considering the interannual change, the JRA-25 reanalysis data shows the best consistency with the observation records, while NCEP/DOE shows the worst. After the analyzing the quality index of three datasets, it is clear that the quality of ERA-interim is better than that of the other two datasets and is improving with time. Another conclusion is that the quality of 2 m air temperature from the reanalysis data is partly effected by ENSO, East Asian and plateau monsoons.

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The spatial distribution of 2 m air temperature difference between three reanalysis data-sets and the observation in the east of Qinghai-Xizang Plateau.Unit:℃.(a) summer,(b)winter,(c)year

 

Interannual change of the regional averaged air temperature at 2 m height (a) and its anomaly (b) from the observation and three reanalysis data-sets in the east of Qinghai-Xizang Plateau.Top:Summer,middle:Winter,bottom:Annual average

The quality index series of reanalysis data and linear regression slope of Q_Y in the east of Qinghai-Xizang Plateau from 1989 to 2009