陇南一次影响农业生产的春季连阴雨成因分析

为减少春季低温连阴雨天气对农作物及经济作物的危害,提前采取效应防护措施,利用常规气象观测资料和陇南市1980—2010年气候评价资料,对2015年3月31日至4月6日春季连阴雨天气成因进行了分析。结果表明,此次连阴雨具有降水时间长、累计降水量大特点,500hPa上阻塞形势建立与崩溃,乌拉尔山高压脊发展及横槽转竖偏北风带下强冷空气是主要成因之一,500hPa高原槽、700hPa上低涡切变线持续也是重要因素,而地面上冷锋和冷高压前冷空气与四川盆地热低压长时间对峙是此次春季连阴雨形成的最主要因素;另外低层持续良好的水汽条件及水汽输送通道和长时间维持的上升运动保证了连阴雨天气的形成。

Cause Analysis of a Continuous Rain in Spring Affecting Agricultural Production in Longnan

In order to reduce the harm of low temperature and continuous rainy weather to crops and cash crops in spring and take protective measures in advance, the causes of continuous rainy weather in spring from March 31 to April 6, 2015 were analyzed by using conventional meteorological observation data and climate evaluation data of Longnan City from 1980 to 2010. The results showed that the continuous rain had the characteristics of long precipitation time and large cumulative precipitation. The blocking situation at 500 hPa was established and collapsed, the development of the high pressure ridge in Ural Mountains and the strong cold air under the cold trough transformed from transversal into upright were one of the main causes. The persistence of the shear line of the low eddy over the 500 hPa plateau trough and 700 hPa was also an important factor, and the long-term confrontation between the cold front and the hot low pressure in Sichuan Basin before the cold front and the cold high pressure on the ground was the most important factor for the formation of the continuous rain in spring. In addition, the continuous good water vapor conditions at the lower level, the water vapor transport channel and the long?鄄term upward movement ensured the formation of continuous rainy weather.