Study of transport and mixing processes in the Banda Sea by tidal currents

本文研究了印度尼西亚海域的潮汐和潮流特征，着重分析了主要的正压M_2和K_1分量。M_2和K_1潮调和常数的计算结果与大量验潮观测结果符合得很好：整个印度尼西亚海域M_2和K_1潮的模型与观测值的均方根误差分别为11.2cm和8.65cm，比以前的研究结果小。潮流场的特征与Wyrtki [1961]报道的特征在性质上相似。在爪哇海和龙目岛和马六甲海峡等狭窄海峡附近发现了相对较强的潮流。在计算的速度场chearly跟踪众多的标记粒子表明，潮流在印尼海域的运输和混合过程中发挥着重要作用。例如，在印度尼西亚东部海域，一个显着的顺时针剩余环流出现在布鲁岛周围，主要是由于潮汐整流在可变的海底地形，与狭窄的海峡周围的非线性效应的影响较小。由塞拉姆海到班达海东部的潮汐余流输送量约为3.8 Sv（1 Sv=10^6m^3s^<-1>），与印度-太平洋贯通流沿东部通道沿着的输送量相当。在印度尼西亚西部海域（爪哇海和马卡萨尔海峡），剩余输送量远小于沿沿着西部航线的通流输送量。然而，我们的研究结果表明，流经这条路线的水的性质可能会被修改周围的马卡萨尔海峡和龙目海峡的大陆架强潮汐混合。

We have investigated the characteristics of tides and tidal currents in the Indonesian Seas, with particular emphasis on the predominant constituents, the barotropic M_2 and K_1 components. The calculated harmonic constants of the M_2 and K_1 tides agree well with those obtained from extensive tide gauge observations : the mean root-mean-square errors between models and observations for M_2 and K_1 over the entire Indonesian Seas are 11.2 and 8.65cm, respectively, smaller than previous studies. The features of the tidal current field are qualitatively similar to those reported by Wyrtki [1961]. Relatively strong tidal currents are found in the Java Sea and in the vicinities of the narrow straits such as the Lombok and Malacca Straits. Tracking of numerous labeled particles in the calculated velocity field chearly shows that the tidal currents play essential roles in the transport and mixing processes in the Indonesian Seas. For example, in the eastern Indonesian Seas a significant clockwise residual circulation appears around Buru Island due primarily to the tidal rectification over variable bottom topography, with a minor impact from the nonlinear effects around narrow straits. The tide-induuced residual transport from the Seram Sea to the eastern Banda Sea attains about 3.8 Sv (1 Sv=10^6m^3s^<-1>), comparable to that of the Indo-Pacific throughflow along the eastern route. In the western Indonesian Seas (the Java Sea and the Makassar Strait) the residual transport is much smaller than the throughflow transport along the western route. Our result suggests, however, that the properties of water flowing through this route could be modificd by strong tidal mixing around the shelf of the southern Makassar Strait ant the Lombok Strait.