The Initial Field Constructions for Numerical Weather Prediction in the Low Latitudinal Regions by a New Mixed Type Autocorrelation Function

應用混合型自相關函數建立低緯度地區數值天氣預報的氣象變數初始場

王光弘(Kuang-Horng Wang) ； 翁興中(Shing-Chung Onn) ； 曾忠一(Chung-Yi Tseng) ； 何臺華(Tai-Hwa Hor)

《Terrestrial, Atmospheric and Oceanic Sciences》 7卷2期 (1996/06) Pp. 189-207

並列摘要

Doppler radar data collected at 7-min intervals by the TOGA radar during TAMEX IOP 13 were used to investigate the time-dependent kinematicstructure of the Mei-Yu front and the associated rainband as it made landfallon the western shore of Taiwan.Using RHI cross sections,chosen to be nearlyperpendicular to the approaching Mei-Yu front,the vertical velocities and divergences were calculated.Using these data,the time-dependent kinematicstructure of the Mei-Yu front and prefrontal convective rainband were analyzed.A careful analysis shows that high speed mid-level dry flow pushes thehigh reflectivity cores at the Mei-Yu front southeastward into the warm sector.In addition,evaporative cooling associated with a strong dry-air intrusion atmid to upper levels combines with precipitation loading to create convectivedowndrafts in a wide-spread area ahead of the Mei-Yu front.The low-levelcold outflow from the downdraft interacts with the moisture-rich southwestmonsoon flow creating a gust front.A smaller portion of the downdraft isalso directed back to the Mei-Yu front sustaining the front.These structuresprovide further evidence supporting the conceptual model put forth in Lin etal.(1992).

並列關鍵字

Numerical Weather Prediction ； Correlation Function ； Objective Analysis ； Optimum Interpolation