颱風過程中海氣交界面上表面重力波的破碎與其引致的白帽對於颱風過程海氣間動量、熱量與氣體傳遞通量具有極大的影響，白帽現象的參數化描述對於颱風的大氣模式、海洋環流模式及波浪數值模式的耦合非常重要。本計畫之目的在於針對颱風過程的海面波場及白帽特性，發展岸基遙測技術，於高風速的極端天氣下進行觀測，量化理解颱風過程中海氣交界面之動量通量特性。本計畫第一年度已完成X band 影像雷達之研製、組裝、測試與率定，同時也進行了中央大學移動式X band 雙偏極化都卜勒雷達海面水相粒子觀測之測試與比對。今年度將對颱風過程中大氣與海洋交界面上的特性進行整合性的岸基遙測：針對重力波方向譜、海面碎波白沫覆蓋等特徵，以自行研製的X-band 影像雷達進行遙測；針對海面白帽與飛沫粒徑、運動速度則應用中央大學X-band 雙偏極化都卜勒雷達進行遙測。為能配合總計畫所擇訂的目標颱風路徑，以上兩套雷達系統皆具有移動能力，可快速動員至颱風登陸週邊海岸進行觀測。在表面流場方面，本計畫將直接應用台灣海洋科技中心的高頻HF band CODAR 雷達觀測結果，獲得颱風過程海洋表面流速特性。本計畫應用三種岸基遙測技術，針對高風速下的海面過程進行整合性的遙測，今年度所獲得之數據，將連同子計畫七楊益博士佈放的深海錨碇，及美方邁阿密大學所佈放的海洋通量觀測浮標ASIS 與EASI Buoy 相互比對驗證，預期將可獲得高風速下海面過程珍貴資料。在此基礎上，後續將進一步應用Philips 的碎波波峰平均長度相關理論，進行波浪特性、海面粗糙度等特性之參數化研究，提供其他子計畫發展數值模式所需。 The breaking of surface gravity waves and relevant whitecapping play major roles on the exchange of momentum, heat and gas between the atmosphere and oceans. In order to develop the coupled atmospheric-ocean-wave numerical model for the better prediction of typhoon intensity, it is essential to parameterize the whitecapping phenomena with respect to the wind/wave fields. The aim of the present study is to collect field data of wave fields and whitecapping under the strong surface wind condition. The invaluable data will contribute to the better understanding of the momentum flux through the air-sea interface. An X band image radar had been self-developed, integrated, tested and calibrated in the first phase of present project. The tests of another mobile X band dual polarization Doppler radar on the remote sensing of the dynamics of water particles on the ocean surface were also performed. In present study, it is the aim to carry out integrated observations of the processes that occurred at the interface between atmosphere and ocean during high wind conditions. The image radar will be applied for the observation of the directional spectra of surface gravity waves and associated whitecap coverage induced by breaking wind waves. The velocity, concentration as well as the size distribution of the spray and droplets of breaking streaks will be observed by the X band dual polarization Doppler radar. The background surface current will be observed by HF band CODAR, which operated by TORI. Three kinds of microwave remote sensing technologies will be applied to the observations of the processes at the air-sea interface during high wind. These data will be calibrated, verified and validated by those measured from the TORI moorings and the ASIS, EASI buoys. Based on the Philips(1985) theory of the averaged length of breaking front, the observed data coule be used for the further parameterization studies, which will also contribute to the development of the typhoon numerical models. 研究期間：9908 ~ 10007
