海洋加热尺度对热带大气垂直环流圈结构的影响

INFLUENCE OF THE OCEAN HEATING SCALE ON THE STRUCTURE OF THE VERTICAL CIRCULATION CELL IN THE TROPICAL ATMOSPHERE

应用Gill本征模的浅水运动方程,在非长波近似下,研究了海洋加热(热源)尺度对热带大气垂直环流圈结构的影响。指出,当热源的纬向尺度小时,大气运动的结构与Gill的长波近似解一致,即在热源中心西侧的Rossby波区,与Walker环流相联系的Hadley环流是热力性的正环流,而在热源中心以东的Kelvin波区,经圈速度的垂直分布与Rossby波区的相反。在低层是向极气流,在高空是向赤道的气流。但当热源尺度大于某一临界值后,经圈环流在Rossby波区和Kelvin波区的大部分地区都是正的Hadley环流。这样一个大尺度正的Hadley环流,将把大量从海洋中得到的热量和能量输送到副热带地区,使那里的大气环流发生异常变化。这一理论结果除与统计事实相符合外,也是对Bjerknes提出的遥相关现象的一个支持。

A steady, shallow water atmospheric model is used to studythe influence of the ocean heating scale on the structure of Walker andHad1ey circulation in the tropical atmosphere. It is shown that whenthe heating scale is smaller than the critical scale, the results are similarto Gill's (1980), that is,a hadley cell is located in the region of Rossbywaves and an anti-Hadley cell in the area of Kelvin waves. When theheating scale is larger than the critical scale. a Hadley cell exists inthe entire heating region. In the latter case, a large scale Hadley cellcan transfer a great amount of heat and energy from the ocean to theextratropical region. This causes the atmospheric circulation there tobe anomalous. The results are consistent with statistical facts and sup-port theoretically the teleconnection which Bjerknes put forward inthe 1960s.