青藏高原地面热源对亚洲季风爆发的热力影响  

Thermal Effect of Surface Heat Source over the Tibetan Plateau on the Onset of Asian Summer Monsoon

作　　者：张艳[1] 钱永甫[1] 

机构地区：[1]南京大学大气科学系,江苏南京210044

出　　处：《南京气象学院学报》2002年第3期298-306,共9页Journal of Nanjing Institute of Meteorology

基　　金：国家自然科学基金重点项目"南亚高压和亚洲季风相互作用及其机理研究"( 4 0 1 75 0 2 1)

摘　　要：利用多年 NCEP/ NCAR再分析全球逐候平均气象场资料和逐旬感热、潜热资料 ,对亚洲夏季风爆发期间青藏高原及其邻近地区地面加热场的特征进行分析。着重讨论了高原和邻近地区感热加热对亚洲夏季风爆发的影响 ,具体分析了高原感热加热对亚洲夏季风推进的影响机制 ,以及对热带低层西风气流的作用。结果发现 ,中纬度高原的感热加热所造成的经、纬向热力差异是导致亚洲夏季风爆发的原因。亚洲夏季风建立区域和时间的差异与高原感热加热的区域性有关。高原感热加热在南海夏季风爆发前后对南海地区低层西风气流所起的作用不同 ,在季风爆发前是加速低层西风 ,在季风爆发后起削弱西风气流的作用。对亚洲夏季风爆发早年和晚年的感热加热进行了对比分析 。Characteristics of the surface heating fields over the Tibetan Plateau and its adjacent areas during the onset period of Asian summer monsoon are analyzed in this paper using the NCEP/NCAP reanalysis pentadly averaged climate fields data and dekadly sensible heat and latent heat data.Effects of the sensible heating over the Tibetan Plateau on the onset of the Asian summer monsoon are discussed.Mechanisms of the Asian summer monsoon progress caused by the Plateau sensible heating and its effect on the tropical low-level west wind are revealed in detail.Results show that the longitudinal and latitudinal thermal contrasts caused by the middle latitude Plateau sensible heating trigger the onset of the Asian summer monsoon.The regional and temporal differences of the Asian summer monsoon onset bear a relation with the Plateau sensible heating region.The Plateau sensible heating has different effects on the low-level west wind in the South China Sea(SCS) before and after the onset of the SCS summer monsoon.It strengthens the low-level west wind before the onset of the monsoon but weakens the west wind after the onset.After analyzing the sensible heat in earlier and later onset years of Asian summer monsoon,it is also found that the interannual variation of the onset date of the Asian summer monsoon are related to the interannual variation of the heat source.

关 键 词：地面热源 青藏高原 亚洲夏季风 热力作用 年际变化 西风气流 

分 类 号：P461[天文地球—大气科学及气象学]