摘要
为了探讨2007年6月7—10日广东东部和珠江三角洲地区持续性暴雨的成因,使用常规气象观测资料、自动站资料以及NCEP的1°×1°的分析资料对这次过程环流特征和影响系统进行分析,同时使用局地经向环流线性诊断模式对这次过程进行模拟诊断。结果表明:这次粤东暴雨过程是在我国中高纬度稳定的两槽一脊的环流形势下,先后受东槽引导从华东沿海南下冷空气和受从西南地区不断东南移短波槽和低涡引导南下的冷空气影响,在华南北部形成稳定的锋面低槽和低空切变线,有利于水汽的辐合和雨带维持;孟加拉湾的西南急流和副高西侧南海西南气流是两支主要水汽输送带;此次暴雨与暴雨区上空中低层正(负)、高层负(正)的垂直螺旋度(散度)变化密切相关。中高纬度和低纬度系统共同影响以及暴雨区高层和低层动力热力条件配合,使得局地经向环流异常,造成了此次持续性强降水。定量诊断结果表明,在各个动力和热力因子中,潜热加热作用对这次暴雨过程贡献最大,此外反映西风急流和斜压槽活动的西风动量平流以及反映北方弱冷空气作用的水平温度平流也有一定的作用。
Abnormal circulation characteristics and causes of the continuously heavy rain in Eastern Guangdong in June 2007 are studied by using observational data, NCEP Global Data Assimilation System data and a linear diagnostic model. The results show that this continuously heavy rain process is associated with the circulation pattern, i.e., two troughs respectively located over Urals Mts and East Asia and a ridge located over northern China. The lower level shear line over northern part of South China contributed to the moisture convergence and rainbelt maintenance in eastern Guangdong. The low-level southwest flow from the Bay of Bengal interacted with that from the South China Sea constituted the major moisture channel. Low-level positive（negative） vetical helicity （divergence） and highlevel negative （positive） vetical helicity （divergence） over eastern Guangdong provided favorable dynamic conditions for development of the convective systems. The numerical diagnostic study results show that the contributions to the ascending motion in eastern Guangdong are mainly from the forcing processes associated with the latent heating, which played the positive and simultaneous feedback role in heavy rain. Moreover, the horizontal transports of westerly momentum and horizontal temperature advection also made some positive contributions to this heavy rain process.
出处
《气象》
CSCD
北大核心
2008年第4期53-60,共8页
Meteorological Monthly
基金
广东省科技计划重点引导项目(编号:2005B32601008)
广东省科技厅地市重点引导项目(编号:2004B32601007)资助
关键词
持续暴雨
西南急流
垂直螺旋度
局地经向环流
continuous heavy rain southwesterly jet vertical helidty local-meridional drculation
