中国区域探空资料与再分析资料风速场的对比分析

利用中国高空探空资料和NCEP/NCAR、ERA以及MERRA三种再分析资料,讨论了再分析资料风速场在中国区域的适用性问题。结果表明:在中国区域的年平均场上,高空风速在我国对流层高层和中层均存在长期减弱的趋势,在我国东部和南部地区的对流层低层也存在减弱趋势,ERA-interim资料和MERRA资料适用性相对较好。再分析资料风速在多年年平均场上普遍小于探空风速。在对流层高层,1980年代至1990年代ERA-interim资料适用性好,而21世纪以后,NCEP/NCAR的适用性较好;在对流层中层和低层,NCEP/NCAR资料适用性较好。在中国区域的季节平均场上,高空风速在冬季的对流层高层和中层中普遍存在增加的趋势,而在春季、夏季和秋季的对流层高层和中层存在减小的趋势。探空资料与再分析资料在冬季偏差最小,在夏季偏差最大。在对流层中层和低层,NCEP/NCAR资料和MERRA资料在冬季的可信度相对较好,MERRA资料在夏季的可信度相对较好;在对流层高层和平流层低层,ERA-interim资料和MERRA资料在四季中的可信度都相对较好。

Comparison of Wind Velocity among Reanalysis and Radiosonde Datasets over China

Using radiosonde and reanalysis data from NCEP/NCAR, European Center for Medium Range Weather Forecasts Reanalysis (ERA), and Modern Era Retrospective-Analysis for Research and Application (MERRA), the applicability evaluation of the atmospheric wind velocity in the area of China are conducted in this paper. The annual mean wind velocity shows a downward trend in the middle and upper tropospheres, and a downward trend in the lower troposphere over the East and South China. Results indicate that the ERA-interim and MERRA wind velocities have better evaluation applicability. In general, the wind velocities of the three reanalysis datasets are lower than observations. In the upper troposphere, ERA-interim is significantly closer to the observed values in the 1980s and 1990s, whereas NCEP/NCAR is much better in the 21st century. In the middle and lower tropospheres, NCEP/NCAR wind velocities agree well with the observed values. In terms of seasonal mean field, wind velocity shows an upward trend in the middle and upper tropospheres in winter, and downward trends in spring, summer, and autumn. The smallest deviation between radiosonde and reanalysis datasets appears in winter, and the largest appears in summer. In the middle and lower tropospheres, NCEP/NCAR and MERRA wind velocities are significantly closer to the observed values in winter, whereas MERRA values are significantly closer in summer. In the tropopause and lower stratospheres, ERA-interim and MERRA wind velocities show significantly better performance in all four seasons.