东亚夏季风年代际变化的波能影响特征

摘要

Based on NCEP reanalysis data , we analyzed the impacts of wave packet propagation on the interdecadal variations in the East Asian Summer Monsoon ( EASM) by using the method of wave packet propagation diagnosis .The results indicated that:when EASM expressed interdecadal variations , the propagation of wave packet also had a certain change .The wave packet propaga-tion was obvious at the lower level , and it became weak at the higher level .So we selected 850 hPa as the studied layer .Over the region of 20°N~50°N, 70°E~120°E, the great value of wave packet spread from 80°S to equator in 1980s and 1990s.During the strong EASM years , the great value of wave packet spread from the middle part of the North Pacific to the northern part of the Northeast Pacific .During the weak EASM years , it spread from the northern part of the Northeast Pacific to the central part of the North Pacific.Over the region of 30°S~25°N, 100°E~160°E, the great value of wave packet spread from 90°S to 30°S in 1990s, and from the East Pacific to the West Pacific .Over the region of 25°S~40°N, 0°~60°E, the great value of wave packet spread from the Atlantic to the Central Pacific , and spread from the East Pacific to the Central Pacific .%利用NCEP再分析资料，通过波包传播诊断的方法，分析了波包传播对东亚夏季风年代际强弱的影响，结果表明：在东亚夏季风表现出年代际强弱变化的同时，波包的传播也随之发生了一定的变化；波包在低层传播比较明显，越往高层越微弱；以850 hPa研究层为对象，在20°N～50°N、70°E～120°E区域里，波包大值在20世纪80年代和90年代，由80°S传到赤道，强季风年代，波包大值由北太平洋中部传向东北太平洋北部，在弱季风年代，由东北太平洋北部传向北太平洋中部。在30°S～25°N、100°E～160°E区域里，波包大值在90年代由90°S传到30°S，从东太平洋传向西太平洋。在25°S～40°N、0°～60°E区域内，波包大值从大西洋传到太平洋中部，又从东太平洋传到太平洋中部。