本研究計畫之首要研究重點為使用2007-2011年追風計畫、2008年T-PARC與2010年ITOP國際觀測實驗所量測的投落送資料來較驗ASCAT衛星散射儀海面風場資料。此研究議題相當重要,因為過去多數作業與研究單位使用來研判颱風七級報風暴半徑與外圍環流結構的QuikSCAT風場資料已於2009年11月停止運作。ASCAT衛星風場則為太空中尚在運作的衛星散射儀(2007年初由歐洲發射)。由於衛星遙測風場資料與其誤差特性對於天氣分析與模式模擬的使用上也相當關鍵,尤其是在資料缺乏的海上,因此一些國際作業單位(NRL)已把散射儀海面風場資料的需求轉由至ASCAT衛星風場提供。然而,ASCAT衛星風場其準確性與相關應用等議題,尚需深入作分析與研究。預期透過這些投落送資料對於ASCAT衛星風場的驗證與較驗研究上,將能提供一個針對颱風周圍風場誤差特性的較驗平台,並透過相關統計誤差特性來修正ASCAT風場所具有的偏差。此外,修正後的ASCAT衛星風場將有助於正確解析颱風外圍結構,並可以同化至颱風數值模式中,藉以提昇颱風路徑、強度與結構演變之作業預報與模擬研究。另一研究重點則規劃進行2008年T-PARC與2010年ITOP國際觀測實驗特殊觀測儀器(包括:投落送、飛行高度資料與SFMR資料、與海洋觀測儀器AXBT資料等)的資料分析、數值模擬與模式同化研究。此外,在獲得ASCAT衛星與飛機資料的誤差特性後,後續的研究將使用這些衛星遙測資料與飛機觀測資料來進行颱風初始化的研究,藉以在颱風數值模式中重建一個與觀測資料相符合的渦旋結構,並探討路徑、強度、降水、眼牆動力、結構變化與地形作用等颱風研究議題。
The major goal of this project is to examine the accuracy of ASCAT scatterometer winds around the tropical cyclone area over the western North Pacific by the dropwindsonde measured by DOTSTAR (Dropwindsonde Observations for Typhoon Surveillance near the Taiwan Region) during 2003-2007, T-PRAC (THORPEX Pacific Asian Regional Campaign) in 2008 and ITOP (Impact of Typhoons on the Ocean in the Pacific) in 2010. Since the QuikSCAT has failed in operation in November 2009. There is still ocean surface vector wind data from the European ASCAT system which provides a partial mitigation for QuikSCAT. Furthermore, the basic knowledge on the accuracy of the ASCAT wind products is very important for weather forecasters and modeling meteorologist, especially for the data poor area around the tropical cyclone system. Another goal will plan to perform the data analysis and model simulation to investigate the special aircraft observation from T-PARC and ITOP project (including dropsonde, flight-level, SFRM, and AXBT data). The validation and investigation of these unique satellite and aircraft dataset can also provide valuable information to reconstruct the inner core structure of tropical cyclone, thus improve the typhoon initialization, structure and intensity simulation in numerical model. Moreover, based on the well represented inner-core simulations, the issues of track, intensity, rainfall, eye dynamic, and structure change of tropical cyclone could be further studied.