低纬高原干季降水与印缅槽的联系

Connection between precipitation of low latitude plateau in dry season and Indian Burma trough

基于1979—2012年GMAO/GES DISC提供的1979—2012年大气环流月平均再分析资料和同期低纬高原及周边地区148个气象观测台站降水数据,运用相关分析、合成分析等统计方法对低纬高原干季降水与印缅槽的可能联系进行诊断分析。结果表明,印缅槽是影响低纬高原地区干季降水的重要因子。印缅槽槽前暖湿偏南风向低纬高原地区输送水汽,槽前的强烈上升运动使暖湿空气在上升过程中有利于发生CISK物理过程,在青藏高原偏北角干冷气流共同作用下,水汽凝结发生降水。印缅槽的发展形成了有利于大气斜压性不断在高原南北侧积累的正反馈机制以及不利于该系统斜压性向下游频散的经向环流形势,从而影响了低纬高原地区各气象要素场的配置,进而影响该地区的干季降水。

Based on monthly atmospheric circulation reanalysis data from Global Modeling and Assimilation Office(GMAO)and Goddard Earth Sciences Data and Information Sciences Center(GES DISC)and precipitation of 148 weather stations in low latitude plateau region from 1979—2012,the relationship between the India Burma trough and the precipitation of low latitude plateau in dry season was investigated by using correlation and synthesis method.The results showed that the India Burma trough was an important factor affecting the precipitation of low latitude plateau in dry season.Water vapor was transported to the low latitude plateau region by southerly wind in front of the India Burma trough.Strong vertical ascending motion in front of the trough promoted the CISK physic process and caused rainfall when met the cold and dry northerlies in the southeast of the Tibet Plateau.The positive feedback mechanism of atmospheric barocline development and radial circulation which would hamper the dispersion process of atmospheric barocline were established when the trough grows strong.As a result,the configuration of the meteorological filed can be affected,which further influenced the precipitation of this region in dry season.