2008年宁夏低温阴雪灾害特征及成因分析

The disaster characteristics of lower temperature and snowy weather and its causes in 2008 in Ningxia

利用宁夏19个气象站1951-2008年1月平均气温和降雪量资料,建立宁夏1月大气干旱指数序列,分析了宁夏2008年1月低温连阴雪极端天气特征;利用北半球500hpa月平均环流特征量、东亚季风资料,分析研究初冬乌拉尔山高压、亚洲区经（纬）向环流、青藏高原南支槽、东亚夏季风向冬季风过渡时期的年代际变化以及太阳活动等外强迫因子对宁夏低温阴雪灾害性天气的影响尺度、幅度及响应时间,结果表明：持续低温阴雪天气的发生是叠加在的大气环流异常形成的;宁夏气温持续异常偏低,部分地区为有气象观测记录以来同期最低值;累计雪量历史同期最大,积雪普遍较厚,连阴雪天数最长;干旱气候变化与外强迫因子相关程度较高,对宁夏冬季短期气候趋势预测具有一定的指示意义。

Using the observational data of January＇s average temperature and snow over 19 stations in Ningxia during 1951 to 2008, the drought index of January was created, and the extreme weather characteristics of January＇s lower temperature and snowy weather was analyzed. Using monthly average atmospheric circulation of 500hPa and East Asian Monsoon, the decadal change of the Urals high and Asian atmospheric circulation and Southern Through of the Tibetan Plateau and East Asian Summer Monsoon in early winter were studied. The results showed that the continuous lower temperature and snowy weather was created by the abnormal atmospheri：c circulation, the temperature was anomalous lower in Ningxia. At the some stations the temperature was the minimum and the accumulative snow was the maximum in January, the days of the continuous snowy weather were the longest, the correlativity of the drought climatic change and the extra - forcing were obvious, and it was available to climatic forecast in winter in Ningxia.