Variability of Western Boundary Currents

近些年来，海洋环流模型有了很大的改进；我们现在能够直接将模型的结果与现场观测进行比较。在本研究中，我们与对西太平洋西部边界流表现出强烈兴趣的国际同事密切合作，加快了这一运动。我们的最终目标是提供用于实际目的的高分辨率海洋模型，例如每日海流预测。在过去两年国际合作研究的基础上，我们成功地取得了几项重要的科学发现，并改进了海洋模型。首先，我们论证了斜压性和海底起伏对黑潮输运变化的共同作用。其次，我们在模型和美国-中国WOCE巡航期间的现场观测中发现并命名了吕宋潜流。第三，我们深入研究了印尼贯流的季节变化，并出版了一期特刊《地球物理杂志》。我们已经在世界各地分发了50本重印本。第四，我们分析了由中间水组成的透镜的形成的俄罗斯数据。第五，在模型结果的基础上，我们在印度洋发现了斯里兰卡穹顶和孟加拉湾穹顶，并利用最新的莱维图斯数据和TOPEX/POSEIDON卫星测高数据证实了这一点。此外，我们还通过比较黑潮天气尺度现象的表面漂移资料和模式变率来检验模式的性能。事实证明，模型的可变性仍然弱于现实。因此，有必要进一步引入改进的亚网格尺度参数化的高分辨率模式。我们计划在目前成就的基础上做到这一点。

Ocean general circulation models have been improved dramatically in recent years ; we are now able to compare directly results from models with in situ observations. In the present study we have accelerated this movement in close cooperation with international colleagues who show strong interests in the western boundary currents in the western Pacific. Our final goal is to provide high-resolution ocean models for practical purposes such as daily ocean current prediction. On the basis of last two-years' international cooperative research, we have been successful in achieving several important scientific findings as well as improvement of ocean models. First, we have demonstrated the role of the joint effect of baroclinicity and bottom relief on the Kuroshio transport variations. Secondly, we have discovered and named <the Luzon Undercurrent> both in models and in situ observations obtained during US-PRC WOCE cruises. Thirdly, we have studied in full depth the seasonal variations of the Indonesian Throughflow and published a special issue of J.Geophys.Res. We have distributed 50 reprint volumes all over the world. Fourthly, we have analyzed Russian data for the formation of lenses composed of the intermediate water. Fifthly, based on the model results, we have found the Sri Lanka Dome and Bay of Bengal Dome in the Indian Ocean and confirmed the existence by the new Levitus data as well as the TOPEX/POSEIDON satellite altimetry data. In addition, we have checked the model performance by comparing surface drifter data and model variability particulary for synoptic scale phenomena of the Kuroshio. It has turned out that the model variability is still weaker than reality. Therefore, it is necessary to introduce further high-resolution models with improved sub-grid scale parameterization. We are planning to do this on the basis of the present accomplishment.