夏季风时期南海扰动对大气热量、动量的调整

HEAT AND MOMENTUM REDISTRIBUTION BY DISTURBANCES OVER THE SOUTH CHINA SEA DURING SUMMER MONSOON PERIOD

摘要:

本文计算了1981年7月到9月南海区域的热量、动量收支,分析了扰动活跃期的运动场特征,讨论了次网格扰动对大尺度热量场和动量场的再分配作用。结果表明,扰动对大尺度场有两方面的贡献。一方面是释放凝结潜热,引起热成风调整,产生更有利于扰动发展的环境场,这是一个正反馈过程。另一方面是扰动对动量场的耗散作用,使运动场均匀化,破坏了扰动赖以存在的环境条件,构成负反馈过程。当正反馈过程占优势时,扰动发展;反之,当负反馈过程占优势时,扰动将消亡。

Abstract:

In this paper, we calculated heat and momentum budgets over the Sooth China Sea during a period from July to September 1981, analyzed the kinetic characteristics during active disturbance period, discussed heat and momentum redistribution of large scale field by the sub-grid disturbances. The result indicates that the disturbances have two contributions to large scale field. One is releasing latent heat that causes adjustment of thermal wind, it formes environmental field which is favourable for development of disturbances. This is a positive feedback process. Another contribution is that the disturbances dissipate momentum field, it makes the kinetic field be uniform, distroies environmental conditions which disturbances depend on. This is a negative feedback process. When the positive feedback process is superior, the disturbance develops. On the contrary, when the negative feedback process is superior, the disturbance disappeares.