Transient, seasonal and interannual variability of the Taiwan Strait current
Transient, seasonal and interannual variability of the Taiwan Strait current
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DOI：
10.1007/s10872-007-0070-1
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发表时间：
2007-10
影响因子：
2.3
通讯作者：
Chau‐Ron Wu;S. Chao;C. Hsu
中科院分区：
文献类型：
--
作者：
Chau‐Ron Wu;S. Chao;C. Hsu
本文建立了一个高分辨率模式，并结合实际水深资料，研究了台湾海峡环流的时空变化。分辨率为3 × 10 km的TS模式的开边界条件来自一个更大尺度的模式。QSCAT/NCEP风场和AVHRR SST提供了海面强迫。由于模式网格和强迫的高分辨率，模式实现了以前无法达到的与大多数观测结果一致的水平。在双周时间尺度上，如果冬季东北风爆发足够强，表面捕获的电流反转往往会导致海峡输送反转。在季节时间尺度上，由于夏季风和气压梯度力都是北向的，所以夏季的北向气流最强。夏季北向流似乎是相对畅通的长云隆起（CYR）和分叉附近的表面。随着秋季东北季风的到来，25.5°N、120°E附近的北向流阻挡了中国沿岸水的下风向运动。在冬季，随着东北季候风增强，向北的海流减弱得更厉害。CCW沿着西部边界顺风移动; CYR阻挡了CCW的一部分，并迫使海峡北方出现U形流型。过去的研究未能揭示冬季在CYR的北方侧翼发展的反气旋涡流。在年际时间尺度上，厄尔尼诺期间减弱的东北季风减少了来自北方的冷CCW的平流，并增强了来自南方的暖水的入侵，导致TS变暖。
We have constructed a fine-resolution model with realistic bathymetry to study the spatial and temporal variations of circulation in the Taiwan Strait (TS). The TS model with a resolution of 3∼10 km derives its open boundary conditions from a larger-scale model. The QSCAT/NCEP winds and AVHRR SST provide forcing at the sea surface. Because of the high resolution in model grids and forcing, the model achieves a previously unavailable level of agreement with most observations. On biweekly time scales surface-trapped current reversals often lead to Strait transport reversals if the northeasterly wind bursts in winter are sufficiently strong. On seasonal time scales the northward current is the strongest in summer since both summer monsoon and pressure gradient force are northward. The summer northward current appears to be relatively unimpeded by the Changyun Rise (CYR) and bifurcates slightly near the surface. With the arrival of the northeast monsoon in fall, downwind movement of China Coastal Water (CCW) is blocked by the northward current near 25.5°N and 120°E. In winter, the northward current weakens even more as the northeasterly monsoon strengthens. The CCW moves downwind along the western boundary; the CYR blocks part of the CCW and forces a U-shaped flow pattern in the northern Strait. Past studies have failed to reveal an anticyclonic eddy that develops on the northern flank of CYR in winter. On interannual time scales a weakened northeast monsoon during El Niño reduces advection of the cold CCW from the north and enhances intrusion of warm water from the south, resulting in warming in the TS.