【作者】 李香淑；

【导师】 郑有飞； 郭学良；

【作者基本信息】 南京信息工程大学 ， 大气物理学与大气环境， 2007， 硕士

【摘要】 本文利用98年5-6月南海季风试验(SCSMEX)加密观测期(IOPs)的TRMM卫星上测雨雷达PR、TRMM微波成像仪TMI的探测资料和产品，研究了南海北部季风爆发前后，海上对流云的水平和垂直结构，并利用格点探空资料分析了南海北部对流云的中尺度结构与对流能量、水汽输送特征。首先，利用热带测雨卫星(TRMM)的雷达(PR)和微波成像仪(TMI)探测信息，研究了1998年5-6月中国南海季风试验(SCSMEX)期间南海北部(15°～25°N，108°～122°E)夏季风爆发期间中尺度对流云的微物理组织结构和降水特征。结果表明，季风爆发前，锋面云带经过我国沿海进入南海后，云带减弱和消散，而季风爆发后，进入南海的锋面云带系统不但没有减弱，而且在南海地区显著加强，发展为较深厚的对流系统，并伴随着强降水过程发生。卫星雷达观测发现，季风爆发前，雷达最大回波和回波顶高度都比较小，而南海季风爆发后，海洋对流发展很快，回波顶高度达到20 km左右。雷达反演的降水分布显示出有强烈的降水发生。卫星搭载的微波成像仪反演的云结构显示出季风爆发期间暖性对流云塔发展旺盛，云冰含量显著增加，主要分布在8 km以上，而且很深厚。地面总降水在季风爆发期间显著增加，且主要为对流性降水，潜热加热率增加2倍以上，且达到对流层顶部，这种潜热的向上输送可能会引起局地大气环流的变化。季风爆发后平均云液、固态水含量廓线分布显示出显著增加的情况，且向高层发展。其次，利用中国南海季风试验(SCSMEX)区1998年5～6月“科学1号”和“实验3号”观测船得到的一天4次加密探空资料及，重点分析了南海北部地区(15°～25°N，108°～122°E)夏季风爆发前后中尺度大气环流的动力、热力和湿度场分布与海洋对流能量和水汽输送特征。结果表明：南海北部季风爆发前后的中尺度大气动力场、温湿场出现快速而明显的变化。季风爆发前，南海北部地区高层辐合、低层辐散，以下沉气流为主；季风爆发后，在200 hPa左右高层辐散、而在900～950 hPa左右低层辐合，并出现强上升气流。这种动力场的显著变化引起温度、湿度场的改变，直接导致南海对流的快速发展，对流活动伴随着剧烈的能量和水汽垂直输送和转化。更多还原

【Abstract】 Using the data of the TRMM-PR, TRMM-TMI in May—June,1998 during theSouth China Sea (SCS) Monsoon Experiment(SCSMEX),the mesoscale structure andthe strong convective transport and transformation of energy and water vapor on thenorth of the South China Sea (SCS) was studied.Firstly, by using data of Precipitation Radar (PR) and Microwave Imager (TMI)sensors on the Tropical Rainfall Measuring Missions (TRMM), the characteristics ofstructure and precipitation of mesoscale convective clouds over northern SouthChina Sea (15°～25°N,108°～122°E) during monsoon onset of south sea in SCSMEXfrom May to June of 1998 has been studied. The results show that the frontal cloudband started to weaken and dissipate as it entered South China Sea from south Chinacoastal region during premonsoon, and intensified and developed deeper convectiveclouds with heavy precipitation during onset of monsoon. The TRMM PR shows thatthe maximum radar echo and echo top was low during premonsoon, and the echoincreased rapidly and echo top reached about 20 km during onset of monsoon.During monsoon period, the precipitation retrieved from PR was strong, the cloudstructure retrieved from TMI shows that the strong and deep convective warm towerdeveloped and cloud ice content enhanced obviously and distributed more than 8 kmlevel and the total surface precipitation increased prominently and was primarily inconvective precipitation. The latent heating rate also increased more than two timesand penetrated the whole troposphere, which might induce the variation of localatmospheric circulation. The profiles of cloud hydrometeors also changed obviouslyduring monsoon period.Secondly, by using the sounding data of four times a day in May—June,1998collected on two observational ships of "Kexue 1 "and "Shiyan 3" during the SouthChina Sea (SCS) Monsoon Experiment(SCSMEX), the mesoscale structure ofdynamics, temperature and moisture, and the characteristics of oceanic convection Transport of energy and moisture were analyzed. The results show that themesoscale atmospheric dynamics, temperature and humidity experienced a rapid andobvious change after monsoon onset over the SCS. In the period of pre-monsoon, theupper air was convergent and the lower air was divergent showing strong downwardair current in the northern SCS. After monsoon onset, the upper air is divergent at200hPa, the lower air was convergent between 900 and 950hPa, showing a strongupward air current. This noticeable change in dynamic field causes the changes oftemperature and humidity field, and directly leads to the rapid development ofconvection over northern SCS, and the convective activity was accompanied byvertically strong transport and transformation of energy and water vapor.更多还原