Establishment and Assessment of the Grid Air Temperature Data Sets in China for the Past 57 Years

Temperature data from meteorological stations in China for the past 57 years are interpolated by introducing digital elevation model(DEM) and taking the edge effect of interpolations into consideration on the basis of the ordinary Kriging method. Using this method, the daily, monthly and annual mean data sets of the grid-based temperature in China with the resolution of 1°latitude by 1°longitude are obtained. The results of the grid data sets quality assessment show that DEM has an apparent effect on the spatial structure of temperatures and plays an important role on interpolations. Great improvements on the spatial interpolation in alpine spots are achieved after exploiting DEM. Compared with station data, grid data sets are more plausible to depict the annual and seasonal mean temperature distribution. The grid data sets can well simulate the spatial difference of the annual mean temperature trends in China. The grid data sets can also well demonstrate the change of annual mean temperature in China which as a whole rises by about 1.6 ℃ for 1951—2007, with a warming rate of about 0.28 ℃/10 a. The warming in the later half 20th century is more rapid than the average values of the world and the Northern Hemisphere. The most evident warming occurs in the past over 20 years. The grid data sets also indicate that: Period from 1998 to 2007 is a decade when the annual mean temperature is the highest since 1951, amongst which the annual mean temperature anomaly in 2006 is close to that in 1998 with the highest value before 2000, and the annual mean temperature anomaly in 2007 with a value of 1.3 ℃ beyond that in 1998, is the highest since 1951.