南海东北部及台湾海峡附近环流的一个耦合模式Ⅰ.模式的建立及背景

通过对南海东北部及台湾海峡邻近海域环流产生影响的各个动力因子进行量级分析,在Hurlburt等人数值模式的基础上,建立起分区性的正压、斜压耦合模式,以便能反映大陆架、大陆坡变化剧烈的底形效应对边缘海环流的影响。将该模式用于南海东北部及台湾海峡附近环流的数值研究。初步的试验计算结果表明,耦合模式能克服两层模式易发生"交面"和"交底"等现象的缺点,同时能反映斜压效应及底形效应的影响,使模拟的计算结果更切合实际,即：（1）黑潮通过巴士海峡侵入南海海域,并导致东沙群岛附近终年存在一个气旋涡;（2）台湾海峡西南海域的大陆架－大陆坡底形效应十分重要;（3）海水在台湾海峡的流动基本上为N向流动,流量约为2×10~6m~3·s-1;（4）模式中有类似于南海暖流的海流出现。

A COUPLE MODEL OF CIRCULATION IN NORTHEASTERN SOUTH CHINA SEA,TAIWAN STRAIT AND ITS ADJACENT WATERS I. MODEL'S SETUP AND ITS BACKGROUND

According to the order analysis of each dynamic factor which affects thecirculation of the northeastern South China Sea (SCS), Taiwan Strait and its adjacentwaters,a divisional area of barotropic and baroclinic couple model is set up based onHurlburt & Thompson's numerical model, so that the violently changed topographiceffect of continental shelf and slope on the circulation of marginal sea can be shown.The model is employed tO the numerical study of the circulation in the northeasternSouth China Sea, Taiwan Strait and its adjacent waters. The computational result ofpreliminary experiment shows that the couple model can not only overcome thetwo-layer model's shortcomings liable to intersect surface and intersect bottom, butalso reflect the baroclinic and bottom topographic effects, so as to make thesimulation results fit the reality much more; i.e.: (1)Most of Kuroshio water heads forthe south shore of the Taiwan Island initially in the direction of incident angle fromeast of the Luzon Island, and then flow northward along east shore of the TaiwanIsland; meanwhile it brings about all-year-long existence of a cyclonic eddy adjacentto the Dongsha Islands. (2)The bottom topographic effect of the continental shelf andslope in the southwestern waters of the Taiwan Strait is very important. (3)The flowin the Taiwan Strait is mainly northward, with transport about 2 Sv. (4)There exists acurrent somewhat like the SCS Warm Current in the model.