南极洲低层两种位势高度再分析资料的比较

比较NCEP/NCAR和ECMWF两种再分析资料南半球低层等压面(700 hPa及以下)的平均位势高度场,结果表明:两者在南极洲差异显著,除12月、1月(南半球夏季)外,NCEP/NCAR资料存在一个虚假的很强的极地高压,而ECMWF资料正常。分析表明该两种再分析资料的上述差异来源于南极洲地面以下虚拟气压场的产生过程;NCEP/NCAR资料较ECMWF少了一个对南极洲过低地面温度的修正。由此得到的NCEP/NCAR资料若用于南半球低层大气环流整体结构的分析,会导致严重的错误。

Comparison of Lower Level Geopotential Height in the Antarctica Calculated from Two Reanalysis Data Sets

Comparison of the Southern Hemispheric lower level(below 700 hPa) isobaric surface geopotential height fields from the ECMWF and NCEP/NCAR reanalysis data sets is performed in this paper,and results show that there was a very significant discrepancy in the Antarctic Continent between the two data sets,i.e.there was a very strong polar high in Antarctica except for the southern summer(December and January) in the NCEP/NCAR data,while it did not existed in the ECMWF data.Analysis indicates that the above discrepancy resulted from the generation process of the virtual pressure fields below the Antarctic ground surface,and comparatively,there was a lack of correction to the underestimated ground temperature of Antarctica in the NCEP/NCAR data.If the NCEP/NCAR data is used to analyze the global structure of Southern Hemispheric lower level atmospheric general circulation,then the results might be severely erroneous.