大尺度環流剖面結構之年際變化與台灣梅雨之活躍度

Interannual Variabilites of the Large-scale Cross-sectional Structure and the Related Activities Taiwan Mei-Yu

陳泰然(George Tai-Jen Chen) ； 周仲島(Ben Jong-Dao Jou)

《大氣科學》 17卷3期 (1989/09) Pp. 223-236

摘要

本文利用NCAR網格點資料，分析1975-1984年台灣梅雨期（5月15日-6月15日）大尺度環流之剖面結構，並探討其年際變化與梅雨活躍度之相關。結果顯示，副熱帶太平洋高壓之強度與位置，為決定台灣梅雨活躍度之先決條件。而中緯度冷空氣南侵以維持梅雨鋒面，為決定梅雨活躍度之必要條件。東亞梅雨區哈德里胞在梅雨顯著時較強，顯示有較強之中低緯度交互作用。此外，並發現梅雨區大氣屬正壓穩定狀態，擾動若有發展，正壓不穩定過程顯然並不重要。

關鍵字

梅雨 ； 年際變化 ； 大尺度環流

並列摘要

NCAR grid point data were used to analyze the cross sectional structure of the large-scale circulations for the Taiwan Mei-Yu season (May 15-June 15) of 1975-1984. The interannual variations of the large-scale circulations and the Mei-Yu rainfalls were also investigated. Results showed that the prerequisite condition for the Mei-Yu activities was the intensity of subtropical Pacific high over the Mei-Yu area. It was also found that the intrusion of the midlatitude cold air was a necessary condition for having an active Mei-Yu season.The local Hadley circulation was stronger over the East Asia for the more active Mei-Yu season. Thus, the more active interactions between the lower- and middle-latitude circulations will be expected. Finally, the atmosphere over Mei-Yu area was found to be barotropically stable. Should the disturbance develop, the barotropic process would not be important.

並列關鍵字

Mei-Yu ； Interannual variability ； Large-scale circulation