2006-06-012024-05-17https://scholars.lib.ntu.edu.tw/handle/123456789/681709摘要：歷年來颱風屢屢造成台灣地區重大災害，颱風研究的重要性不容小覷。國科會於2002年8月起三年內提供相當經費，進行由台大大氣科學系吳俊傑教授所主持的「颱風重點研究」，(National Priority Typhoon Research)。首要研究項目是以「全球衛星定位式投落送」(GPS Dropsonde)進行飛機觀測，名為侵台颱風之飛機偵察及投落送觀測實驗（Dropsonde Observation for Typhoon Surveillance near the TAiwan Region (DOTSTAR)），又名追風計畫。追風計劃是一跨部會、臺美兩國跨國合作、並由我國研究人員主導的國際研究計畫，並與美國國家海洋大氣總署所屬颶風研究中心(NOAA/HRD)、國家環境預報中心(NCEP)等共同合作。此計畫使台灣在國際颱風研究領域中進入新的里程碑，扮演西北太平洋及東亞地區颱風研究的領導角色。 此計畫將使用ASTRA飛機與機載垂直大氣探空系統(AVAPS)設備，以每架次5-6小時時間直接飛到颱風周圍42000英呎的高度投擲投落送，以取得颱風周圍關鍵區域的大氣環境資料：溫度、溼度、氣壓以及風速等，所取得的資料會即時傳送至中央氣象局、NCEP、FNMOC以及JMA，並同化至CWB, NECP（AVN/GFDL）, FNMOC（NOGAPS/COAMPS/GFDN）, UKMET以及JMA等模式中。以期對於颱風分析與路徑預報上提供可貴的資料；增進對颱風動力，特別是邊界層的了解（Wu et al. 2005, BAMS)。其成果更可作為我國及各國未來擬定飛機觀測策略的重大指標，亦有助於推動策略性颱風觀測（targeted observation）。 民國92年9月至今，追風計畫已針對杜鵑、米勒、妮妲、康森、敏督利、梅姬、艾利、米雷、納坦、南瑪都、海棠、馬莎、珊瑚、卡努、龍王等15個颱風完成19航次之飛機偵察及投落送觀測任務，總計在颱風上空飛行99小時、並成功投擲313枚投落送。在觀測的同時，這些寶貴的投落送資料皆即時進入中央氣象局及世界各國氣象單位之電腦預測系統中，協助預測颱風路徑及分析其周圍結構，如暴風半徑（對放颱風假與否具關鍵性影響）。到民國93年底為止，針對追風計畫所得資料的評估結果顯示，投落送資料平均可以改進美國氣象局、美國海軍及日本氣象廳全球電腦模式前72小時颱風路徑預測準確度達20%（Wu et al. 2006, BAMS）。另一方面，投落送也已被成功用來驗證及校正衛星與雷達等遙測資料，藉此提升遙測颱風參數的可信度。追風研究團隊也已經在著名國際學術期刊發表成果論文。 國科會所推動的追風計畫相當圓滿成功，第一期計畫已經在民國94年7月結束。追風研究團隊除持續進行具關鍵性的後續研究外，也正積極規劃第二期追風計畫（民國94至97年），在以中央氣象局為主、加上國科會的合作支持下繼續推動，一方面對國內科技、民生與防災有重大貢獻，另一方面則期望做出具突破性的研究成果，並在國際學術研究領域佔有一席之地。 此委託研究計畫延續第一期追風計畫之成果，並配合第二期之規劃，未來的工作重點將包括： ‧執行95年颱風個案之投落送觀測（預計至少4航次，總飛行時數不得低於20小時，使用之投落送總數不得低於50顆） ‧投落送即時資料分析及氣象局預報參考 ‧颱風飛機觀測作業化技術轉移至作業單位 ‧投落送資料對氣象局（NFS或WRF）模式影響評估研究 ‧提出颱風數值模式使用投落送資料之初始化程序改進建議 ‧颱風觀測敏感區分析技術之理論說明 ‧發展新的Targeted Observation觀測策略即與其他策略之檢驗比較（結合NECP ensemble spreads, ETKF及NOGAPS Singular Vector及Adjoint Sensitivity, ADSSV, 探討最佳投落送釋放位置） <br> Abstract: In light of the heavy damage done by typhoons to Taiwan year by year, the National Science Council (NSC) of Taiwan places a great premium on typhoon research, and therefore funds the "National Priority Typhoon Research" project for three years (from August 1, 2002 to July 31, 2005), especially including the field experiment, “Dropsonde Observations for Typhoon Surveillance near the Taiwan Region (DOTSTAR)”. The DOTSTAR is an international research program conducted by meteorologists in Taiwan partnered with scientists at the Hurricane Research Division (HRD) and the National Centers for Environmental Prediction (NCEP) of the National Oceanic and Atmospheric Administration (NOAA). This project marks the beginning of a new era for the aircraft surveillance of typhoons in the western North Pacific. Built upon work pioneered at NOAA`s Hurricane Research Division (HRD), the key to the project is the use of airborne sensors -- dropwindsondes, which are released from jet aircraft flying above 42,000 feet in the environment of a tropical cyclone. These sensors gather temperature, humidity, pressure, and wind velocity information as they fall to the surface. Information from the surveillance flights is transmitted in near real-time to the CWB of Taiwan, as well as to the NCEP, FNMOC, and JMA. The data are immediately assimilated into the numerical models of CWB, NCEP (AVN/GFDL), FNMOC (NOGAPS/COAMPS/GFDN), UKMET, and JMA. The DOTSTAR are expected to provide valuable data which can help increase the accuracy of TC analysis and track forecasts, to assess the impact of the data on numerical models, to evaluate the strategies for adaptive/targeted observations, to validate/calibrate the remote-sensing data, and to improve our understanding on the TC dynamics, especially over the TC’s boundary layer (Wu et al. 2005, BAMS). Up to now, 19 missions have been flown for 15 typhoons, with 313 dropsondes released. It has been shown that the dropsonde data improve the 12-72-h NCEP AVN track prediction by about 20% (Wu et al. 2006). It is believed that the DOTSTAR experiment has made a significant contribution to the international typhoon research community, and should be worthwhile to be continued. The project is expected to yield impressive breakthroughs in typhoon research, forecasting, and observation when it is completed. Note that the majority of the funding for the flight missions is expected to be funded by the Central Weather Bureau as a joint research project. The foci of the new DOTSTAR project in the 2006 year are: ‧Conducting the DOTSTAR observations（at least 4-6 missions, 20 flight hours, and 50 dropwindsondes deployed per year） ‧Realtime analysis of the DOTSTAR data ‧Collaboration of DOTSTAR with the Central Weather Bureau and other agencies ‧Research on the impact of the DOTSTAR data to numerical models ‧Research on the tropical cyclone initialization procedure related to dropwindsonde ‧Evaluation of the targeted observation strategies (e.g., development of the new scheme we developed on ADSSV, and the comparison of the ETKF, SV, ADSSV, Ensemble variances)颱風重點研究GPS投落送策略性觀測颱風偵察飛機觀測實驗資料同化Priority typhoon researchGPS dropsondeadaptive observationtyphoon surveillance observation experimentsdata assimilation