ABSTRACT

This study investigates the seasonal transport variability of the North Indian Ocean (NIO) boundary currents, in particular, the East India Coastal Current (EICC) in the Bay of Bengal (BoB), West India Coastal Current (WICC) in the Arabian Sea (AS) and Somali Current (SC) in the Equatorial Indian Ocean (EIO) using a high-resolution Regional Ocean Modeling System (ROMS) with climatological river input. The simulation result indicates that northward EICC peaks in March and its mean transport is 2.65 Sv during February to April. The southward EICC extends down to 200 m depth and transports 0.67 Sv during October–December. Northward WICC which extends down to 100 m depth transports 0.31 Sv along the west coast of India during the winter monsoon. Southwestward SC flows between 6.5°N to 3°N, and northeastward cross-equatorial SC goes up to 11°N along the Somali coast. Northeastward SC which is the strongest coastal current in the NIO transports 13.05 Sv during the summer monsoon. The average transport of southwestward SC is 2.57 Sv only. The study suggests that wind stress and wind stress curl (WSC) plays a vital role in the semiannual reversal of transport and remote forcing modulated by equatorial wind anomalies dominates the southward EICC transport.

摘要

本研究调查了北印度洋 (NIO) 边界流的季节性传输变化，特别是孟加拉湾 (BoB) 的东印度海岸流 (EICC) 和阿拉伯海的西印度海岸流 (WICC)​​。 AS) 和赤道印度洋 (EIO) 中的索马里洋流 (SC) 使用具有气候河流输入的高分辨率区域海洋建模系统 (ROMS)。模拟结果表明，北向 EICC 在 3 月达到高峰，2 月至 4 月的平均传输量为 2.65 Sv。向南的 EICC 在 10 月至 12 月期间向下延伸至 200 m 深度并传输 0.67 Sv。在冬季季风期间，向北延伸至 100 m 深度的 WICC 沿印度西海岸输送 0.31 Sv。西南 SC 气流在 6.5°N 到 3°N 之间，沿索马里海岸向东北跨赤道南纬上升至 11°N。在夏季风期间，NIO 中最强的沿海流向东北 SC 传输 13.05 Sv。SC 向西南方向的平均传输仅为 2.57 Sv。该研究表明，风应力和风应力旋度 (WSC) 在半年一次的运输逆转中起着至关重要的作用，由赤道风异常调制的远程强迫主导着向南的 EICC 运输。