摘要
利用美国国家环境预报/大气研究中心(NCEP/NCAR)再分析月平均数据分析了1960—2009年夏季东北冷涡的异常特征,研究了夏季东北冷涡与同期淮河流域降水的关系,发现:东北冷涡偏强时,淮河流域的降水很可能偏多,东北冷涡偏弱时,淮河流域的降水很可能偏少。东北冷涡异常强年,淮河流域高低层环流具有斜压性,且低层有显著的正涡度发展,促进了上升对流运动活跃发展。而东北冷涡活动异常频繁,有利于引导潮湿阴冷的北方气流南下,与东亚夏季盛行的西南暖湿气流在淮河流域上空交汇,在上升运动的触发下,导致淮河流域降水明显增多;东北冷涡弱年的情况正好相反。
The NCEP/NCAR reanalysis monthly data was used to analyze the anomalous features of the summer Northeast cold vortex and its correlation with rainfall in Huaihe river valley from 1960 to 2009. Results show that the more Northeast cold vortex intensity the more rainfall in Huaihe river valley, and vice versa. In the anomalous strong Northeast cold vortex years, the circulation at high-low level over Huaihe River basin had obvious baroclinicity, and the low level was sufficient to develop significant posi- tive vorticity, which promoted the active development of the rising convective motion. Abnormal frequent activities of Northeast cold vortex is possibe to force the damp northern cold air to shift southward, which joined with the southwest warm and humid air prevailling in the East Asian summer over Huaihe River valley. So that the upward motion resulted in signficant precipitation increase in Huaihe River valley, and vice versa.
出处
《气象科学》
北大核心
2015年第2期216-222,共7页
Journal of the Meteorological Sciences
基金
江苏省科技厅科技支撑计划社会发展项目(BE2011818)
淮河流域气象开放研究基金(HRM201006)
江苏省气象科研开放基金(K201006)
关键词
东北冷涡
淮河流域
热力状况异常
海陆热力差异
Northeast cold vortex
Huaihe river valley
Abnormal thermal conditions
Sea-landthermal difference
