高原地区NCEP热通量再分析资料的检验及在夏季降水预测中的应用

VERIFICATION OF NCEP SURFACE HEAT FLUXES OVER QXP AND ITS APPLICATION TO SUMMER PRECIPITATION FORECAST

青藏高原对周边地区的天气气候有重要影响 ,为了寻求表征高原热力作用的新的、长时间序列的资料源 ,本文首先用高原地区NCEP 1 982～ 1 994年间逐月月平均 2 .5°× 2 .5°Lat. Lon.的地面热通量再分析格点资料对照实测值等进行了检验 ,然后用EOF分析方法分析了高原地面热源强度的空间分布特征 ,最后利用再分析资料和降水量实测资料 ,初步分析了高原地面热源强度对我国夏季降水的影响。主要结果如下 :(1 )高原地区的地面热通量再分析资料能较好地反映该区热源强度的年及年际变化特征 ,该再分析资料是可用的 ;(2 )高原地区地面热源强度的分布存在较大的区域性差异 ;(3)高原西北、东北及西南区早春 (2～ 4月 )、夏季 (6～ 8月 )的地面热源强度分别与南疆、河西及长江流域的夏季降水存在反相关关系。

The Qinghai Xizang Plateau (hereafter QXP) has an important effect on weather and climate over its neighbor regions. In order to get a new, long time sequence of the QXP surface heat source intensity data, firstly, the NCEP/NCAR monthly 2.5°×2.5° Lat./Lon. gridded surface heat fluxes over the QXP were verified by comparison with the observed data. Secondly, the space distribution characteristics of the QXP surface heat source intensity (hereafter QXP SHSI) were analyzed by the EOF analysis technique. Finally, the impact of the QXP SHSI on Chinese summertime precipitation has been analyzed utilizing the NCEP/NCAR reanalysis data and the observed precipitation data. The main conclusions are as follows: (1) NCEP/NCAR reanalysis surface heat fluxes over the QXP can represent the realistic QXP SHSI annual and inter annual variability. Therefore, the data is useful. (2) The variability of the QXP SHSI has great space variation. (3) There are negative correlation between the early spring and summer SHSI over Northwest QXP and summer precipitation over south part of Xingjiang. The same things are true for between the SHSI over Northeast QXP and the precipitation over Gansu Corridor and between the SHSI over Southwest QXP and the precipitation over mid and lower reaches of Changjiang River.