北太平洋海温距平对6月长江中下游夏季风影响及其机制的分析

本文首先做了1956—1975年1—5月各月北太平洋海温距平特征向量场与6月长江中下游夏季风的交叉谱分析。结果表明,当不同月份的海温距平特征向量分布形式相似时,它们分别与夏季风的总体相关系数同号,且振荡周期也一致。相关分析还表明,北太平洋经向海温距平梯度造成的异常热成风影响,使西太平洋东西风带强度和副热带高压位置发生异常,从而导致长江中下游夏季风强度的异常。 

THE EFFECT AND MECHANISM OF THE SEA SURFACE TEMPERATURE ANOMALY (SSTA) OF THE NORTH PACIFIC ON SUMMER MONSOON OVER THE MIDDLE AND LOWER REACHES OF THE YANGTZE RIVER IN JUNE

Firstly, sea surface temperature eigenvector fields in North Pacific for each month over Jan-May and cross spectra of summer rnonsoon in the middle and lower reaches of the Yangtze River for June were analysed from 1956-1975. The result shows that the eigenvectors will each go in phase with the total correlation coefficient of the summer monsoon, oscillai.ing in consistent cycles, if the former distribute similarly each other.Further correlation analysis indicates that the influence of anomalous thermal wind, caused by meridional gradients of the sea surface anomaly, changes the intensity of West Pacific zonal wind and the position of sub-tropical high, resulting in consequent change in the intensity of summer monsoon in the middle and lower reaches of the Yangtze River.