亞洲及西太平洋區域超長波之動態及發展研究

王時鼎

中央氣象局

(中華民國六十七年九月二十九日收到)

Abstract

　　In this paper we study the behavior of the extra-long waves at 500mb in Asia. Wavenumber analysis of the monthly mean geopotential height along 50°N and 25°N latitudes, and the daily geopotential height along 45°N from January 1 to February 28, 1975 are examined. From these data the positions and amplitudes of all extra-long waves are identified. We found that the wave numbers 1 and 3 are closely related to the Aleutian low, the semi-permanent ”action center”, while the wave number 2 is probably forced by the continent-Ocean thermal contrast. All these waves shifted eastward in summer time, and westward back to their preferred positions in winter time. The variation in the intensity of the extra-long waves is also examined with aid of daily surface and upper air charts.