消除MODIS图像重叠现象的方法研究

利用常规的探空和地面资料以及NCEP数值预报产品分析场,对2004年7月发生在山西省南部的一次暴雨过程的湿位涡场进行了诊断分析。结果表明:MPV1由负变正标志着暴雨由强到弱。整个过程中,强降水总是发生在MPV1零值线附近。MPV2的正负与低空暖湿气流有着较好的对应关系;对流层高层高值湿位涡向对流层低层下传,引导高层冷空气侵入高温、高不稳定的山西南部,冷空气增强了对暖湿气流的强迫抬升作用,触发不稳定能量的释放,有利于降水增幅,是此次暴雨产生的重要机制。

Analysis of Moist Potential Vorticity of a Rainstorm Process in South Shanxi

Moist potential vorticity field of a rainstorm process occured in South Shanxi Province on July 2004 is diagnosed with the routine meteorolog ical sounding and the ground material as well as the NCEP numerical forecasting product analysis field.The results show that the change of M PV1from negative to positive indicate the change of rainstorm from strong to weak.In the entire process,the strong precipitation always occurs nearby the MPV1zero curve.Positive and negative MPV2 has the better corresponding relations with the lower warm moist current.High value moist potential vorticity of upper troposphere transfer to lower troposphere and lead up per cold air to high temperature and ins tability of South Shanxi,Cold air strengthen the forced lifting effects for wram moist current and trigger the release of unstable energy,that is advantageous to the precipitation increased range,this is the important mechanism of rain storm.