Abstract:

Based upon the regional sandstorm records in Cransu，the geopotential height，temperature and wind fields at mandatory levels generated by NCEP/ NCAR reanalysis dataset(2. 50 X2. 50Lat/Lon) for 46 years(1955一2000)，The 5 active sandstorm years and the 5 inactive sandstorm years in spring over Cransu are selected respectively to contrast the difference on the large一scale atmospheric circulation and the relevant即namical and thermo即namic factors.  The results show that the climatic circulation bac掩rounds between more and less spring sandstorm in Cransu are evidently different.  Therefore，it is revealed the facts that the anomalies of the largescale circulation and the relevant勿namic and thermodynamic factors can result in the formation of firing sandstorm in Cransu.  So that the climatic causes of sandstorm in Northwest China can be understood very well. Abovepreliminary results have some novel and applied value for the climatic prediction of the sandstorm in Northwest China.

Key words: Spring , Active and inactive years of sandstorm, Atmospheric circulation, Contrast analysis.

摘要：

文中使用NCEP/ NCAR 1955~2000年全球月平均再分析网格点资料(2. 50 X2. 50纬度/经度)和甘肃省区域性沙尘暴过程资料,分别选取了甘肃省5个春季典型沙尘暴年份和5个春季非沙尘暴年份,对其气候平均的大尺度环流场和有关物理量场的动力和热力结构差异进行了对比分析。初步探讨了甘肃省春季沙尘暴发生与全球海温异常的关系。分析结果表明.甘肃省春季沙尘暴年和非沙尘暴年大尺度高低空环流场和有关物理量场差异明显‘从而揭示了沙尘暴形成的大尺度环流以及动力和热力因子影响的事实.以期对我国西北地区沙尘暴气候成因有史全而深入的了解为沙尘暴短期气候预测提供理论依据和强信号。

关键词: 春季, 沙尘暴强弱年, 大气环流, 对比分析