夏季台灣近海低壓對台灣天氣之影響

UnsettIed Weather over the Island Accompanied with the Formation of Tropical Disturbances in the Vicinity of Taiwan

劉昭民(Chao-Ming Liu)

《大氣科學》 11卷1期 (1984/03) Pp. 57-69

摘要

夏季（7～9月）台灣附近不但有由高空冷心低壓向下層發展而成的地面低氣壓。也常常有在暖海面上形成的低氣壓。在暖海面上形成的低氣壓，常常向上發展成高空冷心低壓。這些地面低氣壓氣壓值極大參數介於1005－1000MB之間，無論與間熱帶輻合帶（ITCZ）同時存在與否，都常常給台灣各地帶來雷雨或陣雨。所以它的出現，也可提供台灣地區雷陣雨預報之參考。本文謹根據1980－1983年間夏季之氣象資料，將這些暖海面低壓的性質以及對台灣天氣之影響，加以分析。其成因除夏季台灣近海海面非常暖濕外，可能有以下四種：1.東風波。2.強盛的西南風和西南西風。3.冷暖氣團間的輻合作用。4.伴有高空冷心低壓之地面低壓移至台灣附近海面。

並列摘要

In the summer months the water temperature in the vicinity of Taiwan is normally over 27°C. It is favorable for the formation of tropical disturbances while one of the following four synoptic pressure patterns exists in the western north Pacific:1 Easterly waves approaching and passing through the southern part of the island of Taiwan;2. Deep low pressure systems over south China with strong southwest to west southwest flow over Taiwan;3. Intertropical convergence zone over Taiwan, and4. Surface low pressure center associated with the upper cold core low approaching Taiwan.Under the influence of tropical disturbances frequent rainshowers or thunderstorms prevail over the island for a few days or even a week pending the movement of systems.