TOGA-COARE IOP时期大尺度流场的分析

根据ＴＯＧＡ－ＣＯＡＲＥＩＯＰ时期（１９９２年１１月—１９９３年２月）包含加密观测的四维同化的高空格点资料，分析了这一时期热带太平洋风场的大尺度特征，发现５００ｈＰａ以下，在中东太平洋频繁出现大范围稳定的强西风，高层出现明显的东风；低层强西风高频出现区或爆发区逐月向东传播，在观测结束时，西风到达了中东太平洋地区；相应的正常冬季东亚－西太平洋局地哈得莱环流被破坏，热带太平洋的沃克（Ｗａｌｋｅｒ）环流明显地向东太平洋地区移动。所有这些环流的异常特征表明，ＴＯＧＡ－ＣＯＡＲＥＩＯＰ时期正处于一次ＥｌＮｉｎｏ事件的发展时期。

ANALYSIS OF LARGE SCALE FLOW PATTERN DURING TOGA COARE IOP

Based on -DDA data sets (GANAL/JMA) for TOGA-COARE IOP (from November 1992 to February 1993) which incorporated special upper-air observations, the large-scale flow pattern over the tropical Pacific for this period has been analysed. It has been found that frequent occurrence of stable and strong westerly wind or westerly wind bursting below 500 hPa and significant easterly wind at upper level over the central and western Pacific was observed; by the end of IOP, the westerlies shifted eastward to the eastern Pacific; the normal type East Asia-West Pacific Hadley cell and the Walker circulation were destroyed, with a significant inverse circulation sense observed. All the above anomalous circulation features lend supportive evidences for a developing El Niño event during TOGA -COARE IOP.