Analysis for the Structure of Meso-scale Convective Systems on Squall Line Process on July at Shanghai Liu shuyuan Sun Jian ( CAMS, Beijing, China ) Yang yinming (Shanhai Meteorological Center ) Objective Many good work about SL and bow echo have been done by Meteorological scientist. The sketch map has been put forward by the COMET program. Most of the cases which have been analyzed were occurred outside of China. The meso-scale structure hadnt been analyzed in china before the Doppler radar network was established. The structure of the squall line and bow echo occurred at different area maybe not same because of the different climate and terrain. Outline Synoptic view of the weather at July 12 th 2004 Analysis based on the infrared image Retrieved, verified and analysis of the horizontal wind field and reflectivity Conclusion Synoptic overview of the weather at JULY 12 th 2004 Precipitation 28.4mm ; temperature went down 10 0 ; the biggest instantaneous Wind gust up to 29m/s. during this process (local time) Make severe disaster instantaneous temperature the squall line process was happened during 1700 to 1900 July 12th 2004, moved rapidly across Shanghai potential height, temperarure and wind vector: (a)500hPa and (b) 850hPa at 2000 June 12 th Shanghai was located in the front of a cold front, the Low-level southwest jet above shanghai. shandong-anhui-henan-hubei-hunan low eddy This situation is favorable to the squall line s occurring instantaneous wind( automatic-observing station) instantaneous wind Analysis based on the infrared image B C A A 7 12 16:25 17:01 July 12th 7 12 16:25 16:25 July 12th Cloud band of cold front Some MCSs in the front the cloud band The time interval of the infrared image is about half an hour A B C 17:25 July 12th developed very quickly. A and B moved toward east, C moved toward northwest. C A D 18:13 July 12th B these three MCSs did not form a line, one of them was located the place opposites the others. The strong wind shear line was located in the interspaces of three MCSs D-----new Retrieved, tested and analysis of the horizontal wind field The data Shanghai Doppler radar altitude 0.58 km A volume scan per 6,9 elevation azimuth resolution 1 0 radial resolution 0.25 km,range 233 km Because of the data at high elevation is bad, the low elevation data be used only(100*sin0.48 =83.77m ). Retrieved method VAP Velocity Azimuth Processing (put forward by Tao Zuyu 1992) Vr >0 toward radar Vr