摘要
采用2006-2008年自动气象站和2002-2008年TRMM(Tropical Rainfall Measurement Mis-sion)多卫星降水分析(Munti-satellite Precipitation Analysis,TMPA)的夏季(6～8月)逐时降水量资料,分析了青藏高原(下称高原)及周边地区夏季降水的日变化特征,以及高原中部与四川盆地两个特殊地形区降水日变化上的差异。结果表明,高原中部与其以东的四川盆地在降水日变化上有明显不同,即两者的降水日变化具有不同的峰值时间,表现出从高原中部向外传播的特征,最显著的信号出现在高原东缘。同时涡度和垂直速度等物理量也发生变化,因此降水量日变化是各种物理量共同作用的结果。高原地形对周边地区降水日变化有重要的影响,这种影响类似于热带地区海陆边界的影响,表现为高原中部的对流系统多在傍晚前后增强,随后向东传播,在后半夜到达高原以东的四川盆地,形成四川盆地显著的"夜雨",并可能影响到四川盆地以东长江流域的降水活动,这种作用类似于热带地区海陆边界附近的对流传播过程。
The hourly summer（from June to August） precipitation data at two automatic weather stations during 2006-2008 and the TRMM（Tropical Rainfall Measurement Mission） Multi-Satellite Precipitation Analysis（TMPA） during 2002-2008 in the Tibetan Plateau and its neighboring region are used to explore the diurnal variation of summer precipitation.There is a marked difference between the diurnal variation of precipitation in the Tibetan Plateau and that of Sichuan Basin.The peak times of precipitation in a day are,on average,different for the two regions,showing a propagating characteristic from the central Plateau to eastern basin.Usually,the convective systems tend to generate over the central Plateau in the afternoon,strengthen in the evening and move eastward to the eastern edge of the Plateau at night,resulting in the frequent ‘Night Rain’ in the Sichuan Basin.There are corresponding diurnal variations in the horizontal vorticity,vertical velocity and other relevent meteological elements.Therefore,the ‘Night Rain’ in the Sichuan basin is a result of the Tibetan Plateau effect on the diurnal cycle of convective systems.This process is similar to a convective propagation when a diurnal signal over land is spread out over the adjacent oceans in a tropical coastal area.
出处
《高原气象》
CSCD
北大核心
2011年第4期852-859,共8页
Plateau Meteorology
基金
国家自然科学基金项目(40975020,41075067)
国家科技支撑计划项目(2007BAC30B05-4)
国家重点基础研究发展规划项目(2010CB833406)共同资助
