1998年5～8月青藏高原东部和邻近地区大气热源日变化特征及其与高原环流的关系  

Daily Variation of Heat Sources over the Eastern Qinghai-Xizang Plateauand Surrounding Areas and Their Relationship to theCirculation over the Tibetan Plateau

作　　者：简茂球[1] 罗会邦[1] 

机构地区：[1]广州中山大学大气科学系,广东广州510275

出　　处：《高原气象》2002年第1期25-30,共6页Plateau Meteorology

基　　金："青藏高原地-气系统的物理过程及对全球气候影响的理论研究"项目;<国家重点基础研究发展规划>项目 (G19980 40 90 0 )第一部分共同资助

摘　　要：利用 1998年 5～ 8月“南海季风试验”期间观测站的探空及地面资料 ,计算并分析了高原及邻近地区大尺度大气热源和水汽汇的日变化特征及其与高原环流的关系。初步结果表明 :中南半岛—高原东部的大气热源在早上弱 ,傍晚较强 ;南海北部—华南—华中的热源在早上强 ,傍晚弱。水汽汇的日变化与热源基本相似。傍晚高原东部上升运动明显增强 ,高原及其南侧的局地经向季风环流增强 ;高原东部下游地区傍晚的上升运动减弱或变为下沉 ,形成一个西升东降的局地日变热力纬向环流。Using the twice daily routine rawinsonde data in the domain 90°～130°E, -5°～45°N from 1 May to 31 August 1998, the heat source and moisture sink are computed, and the diurnal variation characteristics of heat sources and moisture sinks and their relationship to the circulation over the eastern Qinghai-Xizang Plateau are analyzed. The results show that the heat sources over thearea from Indo-China peninsula to the eastern Plateau are stronger at 12:00 than at 00:00, while the heat sources over the area from the central South China Sea to the central China are strong at 00:00, but weak at 12:00. The moisture sink has a similar diurnal variation to the heat source. The ascending motion over the eastern Qinghai-Xizang Plateau becomes stronger significantly in the evening and the local meridional monsoon circulation also intensifies. Meanwhile, the ascending motion over the middle reaches of Yangtze river at 00:00 becomes weaker and turns to descending motion in the evening. Thus a local thermal diurnal zonal circulation exists with the up branch over the eastern Plateau and the down branch over the middle reaches of Yangtze river. The heavy rainfall in summer, leading to a flooding disaster, occurmainly early in the morning.

关 键 词：大气热源 水汽汇 日变化 高原环流 青藏高原 

分 类 号：P434.5[天文地球—大气科学及气象学]