利用1951~2010年20CR(20th Century Reanalysis Version 2)再分析资料和NOAA海表温度资料研究了赤道印度洋纬向—垂直环流的季节性差异、变化特征及其与Walker环流的关系。本文首先分析了四个季节赤道印度洋上空纬向—垂直环流的结构特征,发现春季和秋季存在严格东西方向上的赤道印度洋纬向—垂直环流。随后,针对春季赤道印度洋纬向—垂直环流变化特征作进一步的分析,研究结果表明,春季纬向—垂直环流的强度及其变率在1951~2010年间持续增强,而该垂直环流的中心位置则表现出明显的年代际变化特征:1981年之前垂直环流的中心位置表现为向西移动,而在1981年后则转为向东移。春季赤道印度洋纬向—垂直环流与Walker环流之间的相关关系同样存在年代际转折,1981年之前两者之间并不存在显著的相关,而在1981年之后,两者之间的关系显著增强。不同年代际时段内赤道印度洋纬向—垂直环流与海温的关系也发生了明显的改变,1981~2010年赤道印度洋纬向—垂直环流主要受到前期和同期太平洋上的ENSO型海温信号的影响,而在此之前该垂直环流主要受到前期和同期赤道东印度洋海温的影响。
By using OLR monthly average data which was observed by American NOAA satellite and 500 hPa ω monthly average data of NCEP reanalysis,the indexes which represented the equatorial longitudinal circulation characteristics were defined. According to the intensity,scope and distribution characteristics of longitudinal circulation in the tropical equator area,the indexes which represented the intensity,position and scope climate characteristics of longitudinal circulation in the equatorial Pacific Ocean were diagnosed and studied. The results showed that the annual variation and interannual variation characteristics of Walker circulation in east-west direction in the equatorial Pacific Ocean were that the intensity and scope existed 5 and 15-16 years oscillatory periods,and the position had 4,12 years oscillatory periods.
