亚洲夏季风活动激发北半球大气遥相关的物理机制探讨 I.正规模及有限时间不稳定奇异矢量分析

Mechanisms of the Atmospheric Teleconnection Associated with Activity of the Asian Summer Monsoon Part I: Analyses of the Normal Modes and the Finite TimeUnstable Singular Vectors

造成大气环流异常的原因可以有两个方面， 一是大气内部的物理过程， 另一方面则可能由大气外强迫引起。在线性框架内， 该文的第 Ｉ 部分利用正规模 （ｎｏｒｍ ａｌ ｍｏｄｅ） 以及有限时间不稳定奇异矢量 （ｓｉｎｇｕｌａｒ ｖｅｃｔｏｒｓ） 理论， 对亚洲夏季风（ Ａ Ｓ Ｍ） 活动激发北半球夏季遥相关型的大气内部物理机制进行了探讨。结果表明， 亚洲季风区的扰动最有效地激发了它下游地区不稳定模态的发展， 从而导致了从亚洲到北美洲一带的大气环流异常。关于从大气外强迫角度对这一问题的探讨， 将在本文的第 Ｉ Ｉ部分发表。

There are two plausible mechanisms which can result in the anomalies of the atmospheric circulation, i.e., the internal and external processes. In Part I, by means of the theories of the normal mode and the finite-time unstable singular vector the internal mechanisms by which the activities of the Asian summer monsoon (ASM) lead to the atmospheric teleconnection during boreal summer are studied. It is shown that the disturbances or waves over the Asian monsoon region are most efficient in exciting the unstable modes along its downstream region, which results in the anomalies of the atmospheric circulation from the Eest Asia across the Pacific to the North America. The results of the external forcing mechanisms related to this issue will be presented in Part II.