摘要
利用NCEP(1°×1°)全球再分析格点资料,对青藏高原东北侧2002年10月18日一次暴雪天气进行诊断分析。结果表明:500 hPa北上的西南暖湿气流与东移南压的西北冷空气在36°N附近交汇形成的高原切变线是造成这次强降水的主要天气系统。暴雪发生在700 hPa湿位涡正压项MPV1正值密集带和湿位涡斜压项MPV2负值区中。由于等eθ线变得陡立密集,大气对流不稳定能量释放,MPV2绝对值增大,大气湿斜压性增强导致下滑倾斜涡度发展是形成此次暴雪的重要原因,它对暴雪预报有着很好的指示作用。
A Snowstorm occurred on October 18,2002 in the northeast side of the Qinghai-Xizang Plateau was analyzed by using the global re-analysis data（1°×1°）of NCEP.The results show that the plateau＇s shear line generated by the combination of the southwest warm moist current moving northward at 500 hPa and the northwest cold air moving to east and west in the region near 36°N resulted in this weather event.This snowstorm occurred in an intensive belt of positive MPV1 at 700 hPa and a negative area of MPV2.The increase of the absolute value of MPV2 and atmospheric moist baroclinicity with the atmospheric convective unstable energy releasing,and the down-sliding slantwise vorticity development were the important reason for the formation of the snowstorm.It has a good indicative effect for the snowstorm forecast.
出处
《干旱气象》
2008年第1期57-63,共7页
Journal of Arid Meteorology
基金
甘肃省气象局青年科技开发基金项目资助
关键词
暴雪
湿位涡
倾斜涡度
snowstorm
moist potential vorticity
slantwise vorticity
