基于交叉小波与小波相干的西太平洋副高与东亚夏季风系统的关联性分析

Correlation Analysis between the West Pacific Subtropical High and the East Asian Summer Monsoon System Based on Cross Wavelet and Wavelet Coherence

采用交叉小波变换与小波相干方法，利用NCEP／NCAR再分析资料以及NOAA卫星观测的OLR资料，分析了2006年夏季西太平洋副高的异常活动及其与东亚夏季风系统相关的时延位相特征。分析结果表明，副高指数与东亚夏季风系统成员特征指数的交叉小波功率谱和小波相干谱能够有效揭示周期尺度为14～20d的不同影响因子与副高指数的时频特征和时滞相关性。分析证实，马斯克林高压和南亚高压对副高的西伸、北跳有较好的预报意义；热带ITCZ和副热带高空急流的加强北移与副高脊线的北跳同步；副高北跳利于降水在华南发生，反过来，雨带的产生又有利于副高的进一步西伸。

Base on the cross wavelet and wavelet coherence transform methods, by using the daily averaged data derived from the NCEP/NCAR reanalysis dataset and interpolated outgoing long wave radiation（OLR） data provided by the National Oceanic and Atmospheric Administration （NOAA）, the abnormal activities of the West Pacific subtropical high during the summer of 2006 and its time-delayed phase characteristics with the East Asian summer monsoon system are analyzed. The results show that the cross wavelet and wavelet coherence spectrum of the subtropical high index and the characteristic indices of East Asian summon monsoon system members can reveal the time-frequency charficteristics and delayed correlation between those different factors and the subtropical high index on 14-20 days time-scale. The Mascarene high and South Asia high may predict the westward extension and northward advance of the subtropical high better; the strengthening and northward movement of ITCZ and the subtropical jet stream are synchronized with the northward jump of the subtropical high ridge;the northward advance of the subtropical high favors precipitation in Southern China, in turn, the formation of rainfall belt benefits the further westward extension of the subtropical high.