夏季青藏高原上中尺度对流系统初生阶段特征  

THE FEATURES OF MCS DURING ITS INITIATION OVER TIBETAN PLATEAU IN SUMMER

作　　者：单寅[1] 林珲[1] 付慰慈[1] 江吉喜[2] 黄签[2] 

机构地区：[1]香港中文大学 [2]国家卫星气象中心,北京100081

出　　处：《热带气象学报》2003年第1期61-66,共6页Journal of Tropical Meteorology

基　　金："国家重点基础研究发展规划"我国重大天气灾害的机理和预测理论研究项目(G1998040908);香港政府"The;;;Earmarked Grant for Research 1999~2000"一种气象卫星数据挖掘及其应用的智能系统项目共同资助

摘　　要：运用1998～2000年夏季青藏高原上182天的极轨气象卫星资料,研究了由计算机客观自动追踪中尺度对流系统(MCS)方法和由此得到的28685个MCSs及提取的相关信息,较为全面地揭示了夏季高原上MCS初生阶段的日频数、强度、形状、日变化、地理分布等诸多特征。得到了高原上每日平均有163个MCSs生成,其中约有76 %的面积仅为数百km2,>104 km2的极少(占4 %);它们的形状多为带状、逗点状以及其他不规则形状,圆形和椭圆形只占近30 %,云顶平均亮温为-51 ℃左右;午后MCS数是上午前期的2倍以上,并且云顶亮温≤-54 ℃的多达5倍以上;它们主要活动在33 oN以南的高原南部,其中在雅鲁藏布江中上游地区和川西至横断山一带各有一个高频中心,这充分展示出南亚季风活动对MCSs初生的主导作用。Using the Polar Satellites IR data in 182 days during the summers of 1998～2000 over Tibetan Plateau, 28685 Mesoscale Convective Systems(MCSS) and some factors of their feature during their initiation, such as daily freguency, intensity, shape, daily variation and geographic distribution, were automatically and objectively tracked and extracted by computer. The results show that the daily mean number of MCSS was 163 of which 76 % was only several hundreds km2 and 4 % of them was>104 km2. Most of them were band, comma and other irregular types and about 30 % of them belonged to circular and ellipse types. The mean minimum temperature at the cloud top was around 51 ℃. MCS number in the early afternoon was over twice that in the early morning and the number of MCSS with TBB≤54 ℃ was five times as many. The MCSS initiating area occarred mainly over the Plateau south of 33 oN where two active regions were over Yaluzangbu River basin and the western Sichuan province to Hengduan Mountain, respectively, and which shows that strong monsoon activity plays a main role in MCS initiation.

关 键 词：极轨气象卫星 夏季 青藏高原 1998—2000年 中尺度对流系统 地理分布 

分 类 号：P458.2[天文地球—大气科学及气象学]