西藏高原對其東側大氣下層所造成影響之實測研究

Observational Study on the Boundary Layer Features in the Lower Atmosphere Caused by the Tibetan Plateau

王時鼎(Shih-Ting Wang)

《大氣科學》 4卷1期 (1977/05) Pp. 11-21

摘要

本文主要係為高空西風帶下風面之西藏高原東側，700 mb層氣流型式之分析研究。發現實測流場中主要均屬中小幅度之運動系統。其基本上與流體流過圓柱後，所出現之各種流型略同。舉凡：尾流（wake），渦旋，渦旋流離（vortex shedding），風切線（shear line）等，均可察出。另發現高原所造成之地形性「射流」（shooting current）每可顯著改變附近之大規模流型。而高原東側在低指標（low index）環流下之「風切線」，每為臺灣地區冬半年長期連續降雨，如「梅雨」，「春雨」，及「冬雨」之主要特徵。且某類「梅雨」型式，實際上每可逕認即為范卡門式渦旋列（von Kármán-like vortex trail）。另外，高原附近之「熱力邊界層」（thermal boundary layer）現象，亦經作個例分析。某些定量之調查與分析經予作出。對臺灣及華南區域冬半年環流型式及天氣預報，可望甚有裨益。

並列摘要

This study is the first part of the research entitled ”hte nature of the atmospheric features cauesd by the Tibetan Plateau and their relationships to the extended forecasting in Taiwan during the cold season”, aiming at the extensive investigation on the boundary layer phenomena in the wake of the plateau. The subtopics include: (1) Typical flow patterns downstream from the Tibetan Plateau. (2) Vortex shedding: (a) von Kármán-like vortex trail, (b) Anticyclonic vortex shedding. (3) The wake patterns and their associated surface features-separated high cells. (4) The shear lines and their associated surface features-stable waves and quasi-stationary fronts. (5) The ”troughing” effect caused by the NW ”shooting flow” and the ”ridging” effect caused by the SW ”shooting flow”. (6) Interaction between the phenomena in the mechanical and thermal boundary layers in the situation of the Tibetan Plateau.