摘要
本文用最大熵谱方法和后延相关分析了1986年夏季风时期60—150°E高空越赤道气流的低频振荡特征,指出30—50天的低频振荡非常显著。其传播特点在低频波位相的持续阶段和转换阶段有所不同。经过带通滤波的高空越赤道气流,其主要经验正交函数EOFI的时间序列能较好地描写东亚夏季风活动。 东业季风分量和东半球500hPa位势高度的后延相关揭示出东亚夏季风同中纬度环流有着明显的低频相互作用,其相互作用的“窗口”是在东亚季风活跃阶段打开的,它同亚洲区域低指数环流和副热带急流的南北振荡相联系。
The characteristcs of the low-frequency oscillation of crcsseguatorial current in the upper troposphere over the area(60?-150? E) during summer 1986 is analyzed by use of maximum entropy method(MEM)and Lag-correlation.
The results indicate that the 30-50 day Low-freqencv oscillation are much significant, the features in their propagation may vary with different stage of low-f reguncy wave.
Passing on the bandpass filter for the crosseguatorial current in the upper troposphere, the times series of the main EOFs describe as the Summer monsoon activitv over East Asia.
In addition, by the Lag-correlation analysis between the component of East Asia summer monsoon and geopotential height at 508 hpa over the eastern hemisph-ere, we found that have obvious low-frequency interaction between the summer monsoon over East Asia and the westerly circulation, the 'window' of which is opened when the summer monsoon is activity in The summer monsoon activity is association with the oscillation in the meridional direction of subtropical jet stream.
出处
《气象科学》
CSCD
北大核心
1989年第1期58-79,共22页
Journal of the Meteorological Sciences
