東南亞河川流域及海洋之碳循環---南海海水通之數值模擬研究值(VI)

Abstract

本子計畫主要是利用數值模式研究南海與菲律賓海、蘇祿海、巽它海峽之海水通量 與交換以提供總計畫及其他子計畫之碳通量與碳循環研究。水量平衡將包括蒸發降雨與 南海周邊地區河川流量，所以本研究將會修改已建立之東亞邊緣海模式(範圍：東經99 度到140度與0度到北緯42度，解析度為1/8°×1/8° )，我們要將河川流量與蒸發降雨的資 訊加入東亞邊緣海模式中，並將新的東亞邊緣海模式的模擬流場先與歷史觀測資料作比 對與驗證，再針對南海的環流與水文（包含表層與深層）作一個較完整的研究與描述， 最後提供正確的海水傳輸量給其餘計畫作參考與研究。 南海雖然是侷限在東南亞的一個半封閉邊緣海，但仍舊會受到全球性氣候環境的影 響，例如聖嬰現象的影響等。除了數值模式外，本計畫亦將使用人造衛星的測高資料來 作輔助工具，來研究黑潮入侵呂宋海峽行為的時空變化，包括季節性變化、季內變化與 年際變化等。

The South China Sea (SCS), bordered by the Asian continent, Borneo, Palawan, Luzon and Taiwan, is the largest marginal sea in the Southeast Asian waters. A string of islands on the east side of the basin separates the sea from the Pacific with three openings. The Luzon Strait is the widest and deepest, allowing inflow and outflow of deep waters. The other two on the northern and southern ends of Palawan exchange waters with the Sulu Sea. The East China Sea to the north and the Java Sea to the south also exchange surface waters with the basin through the Taiwan Strait and the Sunda Shelf, respectively. A small amount of surface water exchanges with the Indian Ocean through the Strait of Malacca. The study of water budget on the SCS is limited because of the complex topographic setting. In the present study, we improve the East Asian Marginal Seas (EAMS) model by adding river runoff and precipitation/evaporation information into the model, bringing the complete model setting for the water budget of the entire basin. The EAMS model domain extends from 99蚩 to 140蚩 in longitude, and from 0衹 to 42衹 in latitude with a horizontal resolution of 1/8� and 26 sigma levels. Since the improved model resolves temporal and spatial scales of interest, we will use the results to discuss the intraseasonal, seasonal and interannual variations of the SCS. Beyond the seasonal time scale, circulation of the SCS demonstrates an interannual variation related to El Ni隳/Southern Oscillation (ENSO). Many recent studies reveal that the ocean dynamics and horizontal advection in particular play a key part in the interannual variability in the SCS. To further highlight the influence from the ocean dynamics on the interannual variability over the SCS, satellite SSH (sea surface height) field instead of SST (sea surface temperature) has been selected for the present study since the oceanic dynamics is better represented by SSH rather than SST, which suffered the heavy influence from the atmosphere (e.g. surface heat flux; evaporation cooling).