局地云量变化气候效应的数值模拟

本文用统计得到的东半球夏季平均云量资料，利用改进的云－辐射计算模式，在三维有限区域模式中模拟局地云量变化的气候效应。模拟结果表明，高原地区和热带辐合带云量变化造成的气候效应都主要表现在青藏高原地区。在低反照率时，高原地区云量减少使该地区地表加热，引起高低空气压系统加强；高反照率时结果相反。热带辐合带云量减少会引起青藏高原地区降温和气压系统减弱。

NUMERICAL SIMULATIONS OF EFFECTS OF LOCAL CLOUDINESS CHANGE ON CLIMATE

A three-dimensional limited area model is used to simulate the effects of change of local cloud amount on climate. In the model,the real summer average cloud amount data in east hemisphere is used and the cloud-radiative computation scheme is improved. Results show that climatic effects caused by the change of the Plateau cloud amount and ITCZ cloud amount are mainly located in the Qinghai-Xizhang Plateau area. When the surface albedo is lower,the decrease of cloud amount in the Plateau area causes the land surface heated,pressure system enhanced both in the lower and the upper atmosphere. When the surface albedo is higher,the results are reversed. The decrease of ITCZ cloud amount causes weakening of the pressure system in the Plateau and cooling of the Plateau surface through the atmospheric circulation.