南亚高压的季节变化与趋暖性

利用NCEP／NCAR再分析资料，分析了南亚高压的季节变化，讨论了对流层中高层温度、整层大气视热源和非绝热加热率的时空变化对南亚高压季节变化的影响。结果表明，南亚高压存在两个季节平衡态，即夏半年的大陆高压和冬半年的海洋高压，大陆高压又可分为青藏高压和伊郎高压。加热场对南亚高压的季节变化有重要作用，南亚高压是一个暖性高压，其中心有“趋热性”，通常位于或趋于加热率的相对大值区。南亚高压的年循环过程，主要受南亚地区潜热和感热季节变化的支配。夏季北方地区和高压地区的强烈短波辐射加热对高压中心北移和维持也有作用，长波辐射的冷却作用则是高压减弱的重要原因。

Seasonal variation and heat preference of the south asia high

By use of the NCEP/NCAR reanalysis data, the seasonal variation of the South Asia high (SAH) isanalyzed. The influences of temporal and spatial variations of the middle and upper level atmospheric tem-peratures, the visible heat sources, and the diabatic heating rates in the whole atmospheric column on theseasonal variation of the SAH are discussed. Results show that the SAH has two seasonal balancing modes,one of which is the land high in summer and the other the ocean high in winter. The land high itself can bedivided into two patterns as well, that is the Tibetan high and the Iranian high. Heating fields have impor-tant impacts on the seasonal variation of the SAH. The SAH is a warm high and its center has the propertyof heat preference, usually locating over or moving to an area with relatively larger heating rates. The annu-al cycle of the SAH is mainly controlled by the seasonal process of the latent and sensible heating in SouthAsia. Strong shortwave radiative heating in the north at high latitudes and over the Tibetan Plateau also hasan effects on the northward movement and maintenance of the SAH. The cooling effect of infrared radiationis an important cause in weakening the SAH.