Abstract:

Based on precipitation and temperature data of 21 stations in January in Ningxia region,  NCEP / NCAR monthly height and wind grid data of 2.5 × 2.5 °over Northern Hemisphere from 1961 to 2008, and NCEP Eurasian snow cover data from 1973 to 2007, the formation mechanism of the extremely cold and snowy weather event accurred in January 2008 in Ningxia region was analyzed. Results show that the anomalous atmospheric circulation was one of the most important causes. La Nina event and Eurasian snow cover anomalies resulted in atmospheric circulation anomaly, then anomalous precipitation occurred in January in Ningxia.

摘要：

用１９６１～２００８年宁夏主要台站１月气温、降水量资料，ＮＣＥＰ／ＮＣＡＲ全球逐月２．５°×２．５°的高度场、风场资料和ＮＣＥＰ１９７３～２００７年欧亚积雪等资料，分析了２００８年１月宁夏持续连阴雪低温极端天气的主要成因。大气环流异常是导致２００８年１月宁夏持续阴雪低温天气的主要原因；前期海温与欧亚积雪异常可能联合作用影响大气环流异常导致此次天气事件发生。欧亚积雪异常影响次年１月宁夏降水异常的可能机制是：积雪异常在积雪异常区激发波动，在３０°～６０°Ｎ通过波列的形式导致大气环流异常，从而影响宁夏１月降水异常。

关键词: 宁夏, 持续连阴雪低温, 成因