不少学者对亚洲地区夏季热带大气环流的中期振荡作过研究,总的说来,发现了4—5天,14天左右和40—50天三种周期的振荡。一般认为,在印度地区,4—5天周期扰动是弱低压西移的反映,而准14天周期振荡则有二种独立的但又有某种联系的说法,一种认为孟加拉湾发生的季风低压发展西移的结果(M.Maruyama),所以其传播位相是向西而略向北的(T.Yasunari),另一种说法是认为印度季风系统各主要成员间一个反馈的振荡(T.N.Krishnamurti,et al),这个印度季风系统主要由印度季风槽、印度上空东风急流、南 Many scholars have studied the mid-term oscillations of summer tropical atmospheric circulation in Asia. Generally speaking, they found oscillations of three cycles of 4-5 days, 14 days and 40-50 days. It is generally believed that in the Indian region, the 4-5-day periodic perturbation is a reflection of the weak and low-pressure westernward movements, while the quasi-14-day periodic oscillation has two independent but somewhat connected terms. One is that the monsoon low pressure in the Bay of Bengal As a result of the development of the westward move (M.Maruyama), the spread of its phase is slightly westward (T.Yasunari). Another is the belief that there is a feedback oscillation among the key members of the Indian monsoon system (TN Krishnamurti, et al.) This Indian monsoon system consists mainly of the Indian monsoon trough, the Indian Ocean’s east jet stream, and the south