“侵台颱風之GPS Dropsonde飛機偵察觀測實驗”（追風計畫）與“颱風及海洋物理及生物地球化學交互作用研究”之研究回顧

A Review on "Dropsonde Observation for Typhoon Surveillance near the TAiwan Region (DOTSTAR)" and "Typhoon-Ocean-Bio-Geochemistry Interaction" Research Projects

吳俊傑(Chun-Chieh Wu) ； 林博雄(Po-Hsiung Lin) ； 林依依(I-I Lin) ； 葉天降(Tien-Chiang Yeh)

《大氣科學》 32卷3期 (2004/10) Pp. 275-292

摘要

有鑑於歷年颱風屢屢重創台灣地區造成重大災害(Wu and Kuo 1999)，颱風研究的重要性不容小覷，國科會已提供相當之經費，於近三年內（自2002年8月l日至2005年7月31日）補助「颱風重點研究 J 。此研究可望增進對於颱風動力理論之瞭解，改進颱風路徑預報準確度，提昇我國在颱風研究領域之國際地位，並扮演西北太平洋及東亞地區颱風研究的領導角色。
本文簡介「颱風重點研究」所推動之兩項重要觀測相關研究。一為使用投落送之颱風偵察飛機觀測實驗（代號：追風計畫）；另一為使用先進衛星資料之「颱風及海洋物理、生物及地球化學交互作用研究」。
追風計畫乃是近十六年來西北太平洋地區首次進行的颱風偵察飛機觀測實驗。研究人員直接飛行到接近台灣的颱風周圍13公里上空，投擲GPS投落送(GPS Dropsonde)，藉此取得颱風周圍最敏感地區的大氣環境詳盡資料。此資料能即時傳輸至中央氣象局資料處理中心，與中央氣象局、美國氣象局、美國海軍、英國氣象局、日本氣象廳之電腦預報模式相結合，除可增進對颱風結構的瞭解外，亦能有效改進颱風路徑、強度及風雨分布的預報。
此重點研究與美國國家大氣及海洋總署所屬颶風研究中心(HRD)及環境預報中心(NCEP)進行密切合作，國內已於2002年8～9月，由主持人帶領四位研究人員（林博雄、劉清煌、洪景山、林沛練）赴美國颶風研究中心，進行為期兩個月的大西洋颶風偵察飛機觀測訓練任務。在經過一連串的準備工作後，於2003年5月23日、6月13日及6月24日完成三次測試飛行，並且進而在2003年9月l日完成歷史性的杜鵑颱風(Dujuan)首航任務，接著更在同年11月2日針對米勒颱風(Melor)進行飛越颱風中心的觀測任務。在2004年，已針對妮妲(Nida)、康森(Conson)、敏督利(Mindulle)、梅姬(Megi)、艾莉(Aere)、米雷(Meari)以及納坦(Nock-Ten)颱風進行共九次觀測飛行。本計畫將持續針對2005年颱風季節期間，在西北太平洋地區威脅台灣的颱風，進行一系列颱風偵察觀測計畫。預期此研究計畫成果將為颱風研究、監測與預報帶來重大突破。
本文亦特別介紹「颱風重點研究」所支持由林依依主導並與筆者合作之「颱風及海洋物理、生物及地球化學交互作用研究」。『颱風及海洋物生地化交互作用』研究乃是國際地球科學界跨領域的一項重大熱門議題，我們透過先進多重遙測技術及模式的整合，獲得有關「颱風引起的生地化反應對海洋初級生產力的影響」及「颱風引起的海洋冷卻現象反饋調節大氣風場」的新突破，並開啓更多有關颱風及海洋物生地化交互作用之新的科學思維。我們進一步計畫將相關遙測資料及概念及數值模式結合，並擴展至颱風強度及氣候反饋問題，相信會持續在此焦點議題上有更多成績。

關鍵字

颱風 ； 追風計劃 ； 初級生産力

並列摘要

A review is presented on highlights of the two research projects under the ”National Priority Research Project”, funded by the National Science Council (NSC) of Taiwan.
In light of the heavy damage done by typhoons to Taiwan year by year, the NSC of Taiwan places a great premium on typhoon research, and therefore provides ample research grant for the ”National Priority Typhoon Research” project for the recent 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-GPS dropwindsondes, which are released from jet aircraft flying above 13km 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.
On September 1, 2003, the first DOTSTAR mission was successfully completed around Typhoon Dujuan. On November 2, the second mission was launched while the aircraft flew over the center of Typhoon Melor. Nine more flights have been conducted for Typhoons Nida, Conson, Mindulle, Magi, Aere. Meari, and Nock-Ten in 2004. As the DOTSTAR research team continues to harvest important data and gain valuable experience, we believe that future typhoon observations will reach full maturity, enabling significant progress in both academic research and typhoon forecasting. It is hoped that DOTSTAR will shed light on typhoon dynamics, enhance typhoon track forecasting accuracy, place Taiwan at the forefront of international typhoon research, and make a significant contribution to the study of typhoons in the Northwestern Pacific and East Asia region.
Regarding the work on the typhoon-ocean-bio-geochemistry interaction, the cooling of the ocean due to the passage of typhoons has been documented from satellite-retrieved SST data. The response to the wind change has also been demonstrated. Meanwhile, a striking interdisciplinary issue on the dramatic bio-response and ocean primary production due to typhoons has also been raised. Inspired by our recent observations, we are developing and using typhoon-ocean coupled models to understand the role of the ocean mixed-layer structure (including typhoon-induced SST cold wake, warm ocean eddies, and ocean currents) on the typhoon-ocean interaction problems and their feedback to the climate and biogeochemistry.

並列關鍵字

Typhoon ； DOTSTAR ； Primary production