赤道西太平洋强东风带特征及其形成机制的诊断分析

A DIAGNOSTIC ANALYSIS OF THE CHARACTERISTICS OF STRONG EASTERLY BELT AND ITS FORMATION MECHANISM OVER THE WESTERN EQUATORIAL PACIFIC

利用１９９３年ＥＮＳＯ事件（４月）爆发前酝酿阶段，ＴＯＧＡ／ＣＯＡＲＥ关键区强化期（１９９２年１１月－１９９３年２月）立体观测实验“向阳红五号”科学考察船定点（１５５°Ｅ，２°Ｓ）高空大气探测资料，分析了西太平洋暖海域上空对流上升区西侧风的垂直变化，指出：对流层上、下部各有一强风带，随着海－气ＥＮＳＯ异常的发展，高空强东风带和低空强西风带均呈增强趋势，最强时分别连续１４天和１８天达到急流标准，占相应航段观测日数的５６％和７２％；强风带强度与对流层顶下逆温层的强度及高度变化有密切关系。

By using the explorational data of the high atmosphere at key area (155°E, 2°S) obtained from three dimensional measurements of international TOGA - COARE project investigated by R/V (Xiang Yang Hong No. 5) during the Intensive Observing Period (Nov. 1992－Feb.1993) before 1993 El Nino (in April) and ENI data provided by CAC of U. S. A, the vertical variations of wind field west of the ascending area of atmospheric convection in the western Pacific warm pool region is analysed. It is pointed out that there is a strong wind belt at the upper and low er parts of troposphere. With the development of air－sea anomalies during ENSO event, the strong easterlies and westerlies in the high and low atmosphere both presented reinforced trend,and sustained for 14 and 18 days and reached jet flow standard which accounts for 56% and 72% of the days of corresponding leg during the strongest period respectively.It is also suggested that the strength of strong wind belt has close relation to the variety ofstrength and altitude of temperature inversion in lower tropopause.