Basic Research on Development of Ocan Prediction Models for Asian Marginal Seas

亚洲边缘海Ocan预报模型发展的基础研究

基本信息

批准号：
11205205
负责人：
YAMAGATA Toshio
金额：
$ 8.77万
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 on Priority Areas
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11205205/
关键词：
The Kuroshio The Tsushima Current The North Pacific Intermediate Water A High-Resolution Ocean General Circulation Model The Okhotsk Sea The Japan Sea Intermediate Water The East China Sea An Ocean Forecasting Mode ネステイング海面高度データハインドカ

项目摘要

The present basic research for developing ocean forecasting models has been conducted jointly by oceanographers of Tokyo Univ., Kyoto Univ., Kyushu Univ., Mie Univ., and Ehime Univ. with a particular Emphasis on the NEAR GOOS region. The major achievements are described in the following.We have developed an ultra high-resolution nested ocean model (with horizontal resolution of 1/18 degree) and have successfully simulated the vertical structure and the path of the Kuroshio. The model also resolves the ocean tide. Analyzing the model results, we have clarified the important role of JEBAR (joint effect of baroclinicity and bottom relief) in steering the Kuroshio eastward in the region southwest of the Kyushu Island ; the role of the bottom torque is to drive the Kuroshio into the deeper region. Tracer experiments show that about 50% (20%) of the water mass of the Tsushima Current is from the Taiwan Strait and another 50% (70%) is from the Kuroshio in summer (winter).The outflow of the Okhotsk Sea water of low potential vorticity is one of origins of the North Pacific Intermediate Water. Using a high-resolution non-hydrostatic ocean model, we have shown that eddy shedding due to the baroclinic instability of the front formed by tidal mixing plays a crucial role in this process. The water left from the Okhotsk Sea penetrates even into the Shikoku Basin.The RIAMMOM ocean model is successfully used for hindcasting experiments of currents in the Japan Sea. The data assimilation method used in the experimens is based on the Kalman filter. We have demonstrated that the ocean forecasting limit is about two months. We have also shown that to resolve downwelling associated with baroclinic instability as well as convection along the ocean front is a necessary ingredient to simulate realistical ly subsurface and intermediate conditions in the Japan Sea.

目前开发海洋预报模型的基础研究是由东京大学、京都大学、九州大学、三重大学和爱媛大学的海洋学家共同进行的。特别强调近地轨道区域。主要成果如下：研制了超高分辨率嵌套海洋模型（水平分辨率为1/18度），成功模拟了黑潮的垂直结构和路径。该模型还解决了海洋潮汐问题。通过对模型结果的分析，明确了JEBAR（斜压与底部起伏的联合效应）对九州岛西南地区黑潮东移的重要作用；底部扭矩的作用是驱动黑潮进入更深的区域。示踪实验表明，对马海流约50%（20%）水团来自台湾海峡，夏季（冬季）另有50%（70%）来自黑潮。低位涡是北太平洋中层水的成因之一。使用高分辨率非静水海洋模型，我们表明，潮汐混合形成的锋面斜压不稳定性导致的涡流脱落在此过程中起着至关重要的作用。鄂霍次克海留下的水甚至渗透到四国盆地。RIAMMOM海洋模型已成功用于日本海海流的后报实验。实验中使用的数据同化方法是基于卡尔曼滤波器的。我们已经证明海洋预报的极限是两个月左右。我们还表明，解决与斜压不稳定相关的下降流以及沿海岸线的对流是模拟日本海真实地下和中间条件的必要因素。