三种再分析资料的高空温度与中国探空温度资料的季节平均特征对比分析

Comparative Analysis on Monthly Mean Characteristic of Free Atmospheric Temperature between Three Reanalysis Datasets and Radiosonde Dataset in China

利用中国105个测站的探空资料以及NCEP/NCAR、ERA和JRA三种再分析资料,采用线性趋势和EOF分析等多种统计分析方法,对再分析资料的季节平均高空温度在中国区域的可信度进行了分析。结果表明,在数值上,春、夏、秋季的分布形势较为相似,大多表现出NCEP资料在对流层上层与探空资料更为接近,ERA和JRA资料在对流层中下层与探空资料更为接近,而冬季与其他季节差别较大;在描述长期变化趋势方面,不同季节不同资料的情况不一致,特别是夏季我国南部地区的对流层中层存在较大范围的降温趋势;在不同区域上,相比于探空资料,三种再分析资料在我国北方的描述能力比南方好,东部比西部好;在时空变化特征方面,三种再分析资料第一模态的分布在不同季节差异较大,而第二模态的分布在各季节则较为一致,大多表现出整层温度南北反位相变化的特征。

Based on the radiosonde dataset from 105 stations in China, NCEP/NCAR reanalysis data- set, ERA reanalysis dataset and JRA reanalysis dataset, the study of reliability of free atmospheric temper- ature from reanalysis datasets based on the monthly mean in China is performed using the means of linear analysis and EOF（Empirical Orthogonal Function） decomposition. The results show that. In numerical as- pects, the situations in spring, summer and autumn are similar, differing from winter, which show that NCEP dataset is more close to the radiosonde dataset in upper troposphere while ERA and JRA dataset are more close to the radiosonde dataset in middle and lower troposphere. In terms of long-term trend, the dif- ferent datasets in different seasons reveal the different characters, especially the cooling trend in the south region of China in middle troposphere in summer. In different areas, three reanalysis datasets display more reliable in the north area of China than in the south area, and more reliable in the east area than in the west area when compared to the radiosonde dataset. In the aspect of spatial and temporal variation characteris- tics, there are quite differences of three reanalysis datasets in the distribution of the first mode. The sec- ond mode correlates quite the same with each other in four seasons, which displays the feature of the oppo- site phase change between north and south of the whole layer temperature.