摘要
105°E越赤道气流的发展变化与南北半球的大气环流系统发展变化有关,但这些环流系统并非同时起同样重要的作用。作者利用候平均OutgoingLongwaveRadiation(简称OLR)资料与850hPa风场资料(1979～1986年)对热带东印度洋—西太平洋海域与(夏季)越赤道气流有关的环流系统做相关分析和越赤道气流偏强类合成分析。结果表明,夏季海洋大陆赤道缓冲区的对流上升运动(90°E～120°E,5°N～5°S)、澳州大陆冷性高压(10°S～30°S,120°E～155°E)的发展,都影响2～3候以后105°E夏季越赤道气流;澳洲大陆北部的冷性高压,西太平洋副热带高压西端位置西伸或东缩造成的东中国海季风区上升运动的变化,又是南北半球环流同时影响CEF变化的具体表现。南半球澳洲冷性高压北部(10°S～25°S,120°E～170°E)的辐散下沉气流对CEF加强起决定作用。
E CEF has a close relation with Southern Hemisphere and Northern Hemisphere circulation systems, but these circulation systems do not affect CEF at the same time or do not have the same impact in CEF variation. Based on the pentad mean Outgoing Longwave Radiation (shorted as OLR) and 850hPa wind data during 1979 to 1986, the circulation in the tropical eastern Indian Ocean and western Pacific Ocean are analyzed. The correlogram of CEF and OLR and the composite chart of 850hPa wind field while CEF is stronger show that in summer both the ascend motion of the buffer zone (90°E^120°E,5°N^5°S) and the variation of the Australia anticyclone (10°S~ 30°S, 120°E^155°E) affect CEF 2~3 pentads later. The Australia anticyclone and the west part of the Subtropical anticyclone in the Western Pacific (Eastern China Sea monsoon region) are the indication of the joint impact of Southern and Northern Hemisphere circulation on CEF. The divergence descend wind of the Australia anticyclone, especially in the north part (10°S^25°S, 120°E^170°E) has a decisive effect on CEF variation.
基金
国家自然科学基金课题!( 4 9776 2 86 )资助
关键词
海洋气象
越赤道气流
环流系统
夏季
tropical eastern Indian Ocean and western Pacific Ocean
cross equator flow
Australia anticyclone
circulation system
summer
