近30年青藏高原大气热源气候特征研究

Climatic Characteristics of the Atmospheric Heat Source over Tibetan Plateau in Recent 30 Years

利用NCEP CFSR再分析资料,用＂倒算法＂计算了1981~2010年青藏高原大气热源汇,并分析了其气候特征。结果表明：（1）青藏高原大气热源汇具有明显的季节差异。高原大部分地区在春季和夏季为热源,冬季和秋季为冷源。2~4月热源从高原西北部、东北部及西南边坡开始逐渐向中部扩展,强度不断增强。5~7月高原东南端热源显著增强并向西向北扩展,使7月高原热源达到最强,并在高原南部喜马拉雅山脉沿线及其以南邻近地区形成一个强大的热源带。8月开始,高原热源迅速减弱,高原中部至四周边坡大部分地区大气先后变为冷源。到11月和12月整个高原大气几乎为冷源。（2）高原各区逐年平均大气热源强度有明显不同的变化特征。高原全区有显著的2~3年和6~8年周期,而高原东部仅存在6~8年周期,高原西部仅有2~3年周期。（3）近30年高原全区和东部大气热源具有明显增强趋势,而高原西部却为减弱趋势。

This paper calculated heat source and heat sink over the Tibetan Plateau （TP） during 1981 -2010 by use of the NCEP CFSR reanalysis data and the ＂inverse algorithm＂, and discussed the climate regimes and change of the thermal sources over the TP. The results suggest that ： （ 1 ） The atmospheric heat source and heat sink have obvious seasonal variations over these areas. The most part of TP acts as a heat source in Spring and Summer, while it acts as a cold source in Winter and Autumn. From February to April, the scope of heat source expands gradually from northwest and northeast plateau and south- west slope to the center of TP, and its intensity enhances obviously. From May to July, The heat source over southeast part of TP enhances and expands to the west and north significantly. In July, the southern tip of TP along the Himalayan mountain area has become a strong heat source belt, with its strongest value appearing. Beginning in August, the heat source over TP starts to weaken. The areas become cold sources successively from the center to side slope of TP. In November and December, the whole TP area almost has become a cold source. （2） The yearly average intensity of the atmospheric heat source over the whole area of TP, the Eastern or the Western Plateau has obvious different change features. The intensity of heat source in the whole area of TP changes with periodicities of 2 - 3 years and 6 - 8 years, while in the Eastern Plateau is 6 ~ 8 years, in the Western Plateau is 2 - 3 years. （3） Over recent 30 years, the atmospheric heat sources in the whole area of TP and the Eastern Plateau have significantly enhanced trend, while in the Western Plateau it takes on a down trend.