Abstract:

Based on yearly temperature，precipitation data in central Hexi Corridor，and the historical data of the intensity，area and the west ridge point of Subtropical High and Polar vortex intensity，meridional circulation provided by national climate center，the characteristics and the courses of the anomalous rain － snow weather event in central Hexi Corridor which was happened in 2010 spring were analyzed． Results show that the increasing magnitude of precipitation and long duration of lower temperature in spring of 2011 in central
Hexi Corridor were rare in recent 40 years，which caused by the stronger Polar vortex intensity and Asian meridional circulation，and the cold air over high latitude region moving strongly to south． Another factors were the phenomenon of El Nino in 2009，and the abnormaly extending westwards and stronger intensity of Subtropical High． In addition，the effect of this weather event on the spring sowing was analyzed also，and the defense measures and some suggestions were provided．

Key words: rain － snow events in spring, weather features, causes analysis, disaster prevention, middle of Hexi Corridor

摘要：

利用河西走廊中部6 县( 区) 历年降水及温度等常规资料、国家气候中心提供的74 个大气环流因子中西太平洋副热带高压强度、面积、西伸脊点指数及极涡强度、经向环流指数等历史资料，分析河西走廊中部2010 年春季异常低温阴雨雪天气特点及其成因，结果表明: 2010 年春季此区域降水偏多幅度之大、低温持续时间之长为40 a 来罕见; 2010 年春季河西走廊中部天气气候异常是极涡中心指数及亚洲经向环流指数偏强、高纬度强冷空气大幅南下等因素引起的; 2009 年厄尔尼诺现象的出现及2010 年春季副热带高压异常西伸偏强，也是低温阴雨雪天气形成的原因。此外，还分析了2010年春季低温阴雨雪天气对河西走廊中部春耕春播生产的影响，并提出防御措施及建议。

关键词: 春季低温阴雨( 雪) , 天气特征, 成因分析, 灾害防御, 河西走廊中部