西太平洋夏季赤道反气旋形成过程的探讨

ON THE FORMATION OF THE SUMMER EQUATORIAL ANTICYCLONE OVER THE WESTERN PACIFIC

摘要:

夏季(主要是1979年)的资料分析表明,当北半球西太平洋地区有一个或几个低压系统形成并在其南侧10°N附近出现大片热带西风时,即使南半球没有寒潮爆发,赤道附近偏东风没有加强,也会使低压南侧0°-10°N地区(-Δu/Δy)出现很大的负值,有利于赤道缓冲带或赤道反气旋的发生发展。相反,当北半球热带及副热带地区受高压影响时,赤道两侧都盛行偏东气流,赤道附近(-Δu/Δy)值很小,此时即使南半球有寒潮爆发,也不会形成赤道缓冲带和赤道反气旋。

Abstract:

Analysis of weather data for the summer of 1979 shows that. when one or more low pressure systems are found over the western North Pacific with a wide stretch of tropical westerlies to the south of 10°N.large negative values of -(Δu/Δy) may appear in the area between 0° and 10°N. south of the low pressure belt. even though there is no cold outbreak in the Southern Hemisphere nor notable increase of easterlies along the equator. This favors the development of the equatorial buffer zone or the equatorial anticyclone. On the contrary. when the tropical and subtropical area of the Northern Hemisphere is under the domination of the high pressure belt and easterlies prevail on both sides of the equator.the value of -(Δu/Δy) would be quite small and no buffer zone or tropical anticyclone would form regardless of cold outbreaks in the Southern Hemisphere.