| 摘要: | 本研究針對台灣西部海岸環境進行長期背景監測以及相關海岸環境水動力監測技術與分析方法研發。計畫針對西北海岸之桃園藻礁周邊海岸，建置定點海岸監測實驗站，作為觀測據點與研究與新開發技術測試平台，在長期環境背景監測方面：自2010年起迄今已經累積多年海岸帶海氣二氧化碳通量觀測資料、近岸海水水質時間序列資料。今年度除了將持續進行海域環境背景參數監測，同時將進行新的觀測、演算法技術研發與現場測試。新的觀測技術包括兩者：第一為內陸棚海域的混合、擴散與輸送觀測技術；第二為高頻陣列雷達對於台灣海峽風場、波浪場與流場的遙測技術。前者，其目標在於理解和掌握陸源污染物在近岸水體，尤其是內陸棚範圍內的混合與擴散過程。本計畫以自主研製之海表漂流浮球陣列為觀測工具，以Lagrangian方式對藻礁周邊之內陸棚海域的流場進行觀測，實現對近岸污染物擴散與混合特性參數定量評估，主要討論水平延散特性受紊流與層化效應之影響。高頻陣列雷達方面：本計畫今年度將於桃園新屋海岸監測站建置美國夏威夷大學研發的32支天線高頻陣列雷達系統，並進行波浪場的解算方法研究。解算方法將使用Barrick(1972) 與Gill et. al. (2006)的二階峰理論，分析雷達回波都卜勒-距離譜，解算波高、週期、波向與方向分佈參數，探討其於台灣海峽北段的時空演變。本研究今年度首先將透過數值模擬方式驗證解算方法的正確性，明年度進一步應用在季波波浪觀測數據的分析，實現台灣海峽100公里範圍內海域高時空解析度波浪場的長期監測。 ;The aims of present study are twofold, first to provide the long-term monitored data as the coastal environment baseline at the western coast of Taiwan and second, study the coastal mixing processes using the latest technologies. In present project, a coastal monitoring station had been set up near the Taoyuan algal reef and served as a test platform, from which the continuous time series of the air-sea CO2 flux, sea water quality data and nearshore hydrodynamic data have been recorded since 2010. In this year, the coastal monitoring station will be operated, maintained and expanded, in terms of observation item, under the support from this project. A state-of-the-art HF coastal radar system that consisted of 32 antennas array will be installed in the station for the mapping of wave field, current field and wind field of the northern Taiwan Strait. For the high frequency radar: two HF-radar systems with 32 antennas and 16 antennas arrays each, that developed by University of Hawaii, will be set up at the NCU coastal observatory. The radar systems, which are provided by Prof. Pierre Flament at University of Hawaii under the collaboration agreement with National Central University, are working at 24MHz. This radar system features the finest azimuthal resolution worldwide that especially designed for wave field mapping. It is planned to install the radars in 2018. In present study, a simulation test bed (End-to-End-Simulation, E2ES) for HF radar will be setup to validate and test the algorithms for wave parameters including wave height, period, propagate direction and directional spreading and also the directional wave spectrum. The E2ES will be setup based on the theories of second-order radar echo proposed by Barrick (1972) and Gill et al. (2006). Doppler-Range spectra will be simulated for monsoon and typhoon conditions as the given target. Algorithms and estimators that proposed by Barrick(1977), Marresca (1997), Graber et. al (2000) and Grugel et. al.(2006) will be implemented and tested and tuned. Concerning the tuning, the coupling coefficient in the theory for the EM wave and surface gravity waves will be discussed from both theoretical foundation and experimental data.For the coastal mixing in the inner shelf, which is the dominating processes in the land-ocean interactions, will be discussed using observational data. The self-developed miniaturized surface drifters array will be deployed in the field campaigns in the vicinity waters around the Taoyuan algal reef. These surface current maps and their temporal evolution will be used for quantitatively assess the mixing efficiency under various turbulence and stratification conditions. |
