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Seasonal and interannual variations in the Indian Osean

印度海洋的季节和年际变化

基本信息

批准号：
06452085
负责人：
YAMAGATA Toshio
金额：
$ 4.67万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-06452085/
关键词：
Indian Ocean Ocean General Circulation Model Monsoon Seasonal Variations Interannual Variations Indonesian Throughflow Nondispersive Long Possby Waves Coastal Trapped Waves ロスビー長波海洋物理学吉田-Wyrtkiジェットケルビン・ジェット

项目摘要

A holizontally high resolution Indo-Pacific ocean general circulation model, which can resolve the detailed geometry and bottom topography in the Indonesian archipelago as well as the whole Indo-Pacific region, is developed and used to investigate seasonal and interannual variations in the upper layr thermal structure and the circulation in the Indian Ocean and the Indonesian Throughflow. The outcomes of this study are as follows :(1) Simulated seasonal variability of the Indonesian Throughflow, seasonal and interannual variations of the upper layr thermal structure in the Indian Ocean are both consistent with the observed data such as the XBT and CTD data, the sea surface height variations derived from satellites, the surface drifting buoys, and the tide gauge dada. This indicates that the numerical model is an efficient tool to investigate the seasonal and the interannual variability in the Indian Ocean.(2) The seasonal variability of the Lombok throughflow consists of the annual and … More the semiannual harmonics. While the annual siganl is forced by the local monsoonal winds over the Indonesian archipelago, the semiannual signal is associated remotely with the Kelvin waves generated twice a year during the monsoon transition time in the central equatorial Indian Ocean. On the other hand, the coastally trapped waves around Australasia, which are forced by the winds along the southwestern coast of Australia associated with the meridional movement of the southern hemisphere westerlies, play an important role in the seasonal transport variation through the Timor Sea. Furthermore, the simulated annual-mean Throughflow does not show the simple Sverdrup dynamical balance. It turns out that considerable concellation of terms in the momentum equation is involved in producing a near-Sverdrup balance in the model.(3) The seasonal and the interannual variations of the simulated and the observed depth of the 20ﾟC isotherm show a band of large amplitude between 8ﾟS and 20ﾟS across the Indian Ocean, and the signals propagate to the west. The generation of those signals is well explained by a simple model which consists of the local Ekman pumping velocity and the nondispersive, long Rossby waves. The signal radiating from the eastern boundary of the Indian Ocean contributes only about 10% of the annual signal ; however, it affects the interannual variations in the eastern part of the southern tropical Indian Ocean. Less

本文发展了一个整体高分辨率的印度-太平洋海洋环流模式，该模式可以分辨印度尼西亚群岛和整个印度-太平洋地区的详细几何形状和海底地形，并用于研究印度洋和印度尼西亚横流上层热力结构和环流的季节和年际变化。研究结果如下：(1)模拟的印尼贯穿流季节变化、印度洋上层热结构的季节变化和年际变化与XBT和CTD资料、卫星海面高度变化、地面漂流浮标和验潮仪数据等观测资料基本一致。这表明数值模式是研究印度洋季节变化和年际变化的有效工具。(2)龙目岛贯穿流的季节变化由年变化和…变化组成更多的是每半年一次的谐波。虽然每年一次的信号是由印度尼西亚群岛上的当地季风迫使的，但半年一次的信号与赤道印度洋中部季风过渡期间一年两次产生的开尔文波是遥相呼应的。另一方面，由于南半球西风带经向移动，沿澳大利亚西南海岸的风所强迫的澳大拉西亚沿岸附近的海浪在帝汶海的季节输送变化中起着重要作用。此外，模拟的年平均通量并没有表现出简单的Sverdrup动态平衡。(3)20ﾟC等温线的季节变化和年际变化表明，在8ﾟS和20ﾟS之间，印度洋有一个较大的波幅带，信号向西传播。这些信号的产生可以用一个简单的模型很好地解释，该模型由局部Ekman泵浦速度和非色散的长Rossby波组成。从印度洋东部边界辐射出来的信号只占全年信号的10%左右，但它影响到南热带印度洋东部的年际变化。较少