Effect of meridional wind on gap-leaping western boundary current  

作　　者：王铮 袁东亮 侯一筠 

机构地区：[1]Key Laboratory of Ocean Circulation and Waves, Chinese Academy of Sciences [2]Institute of Oceanology, Chinese Academy of Sciences [3]Graduate University of the Chinese Academy of Sciences

出　　处：《Chinese Journal of Oceanology and Limnology》2010年第2期354-358,共5页中国海洋湖沼学报（英文版）

基　　金：Supported by the Knowledge Innovation Program of Chinese Academy of Sciences (Nos. KZCX1-YW-12, KZCX2-YW-201);the National Natural Science Foundation of China (No. 90411013);the National Basic Research Program of China (973 Program, No. 2006CB403600);NSFC's Outstanding Youth Grant (No. 40888001);the 100-Talent Program of the CAS, and the Outstanding Youth Grant of Shandong Province

摘　　要：Using a 1.5-layer reduced-gravity nonlinear shallow-water equation model, we studied the effect of the meridional wind on the western boundary currents (WBC) at critical states with hysteresis courses. The results of the simulation indicate that the WBC is prone to penetrating into the gap under northerly winds, and its path is more difficult to alter due to the larger interval between the two critical transition curves (C1P and C1L). For southerly winds, the WBC is prone to leaping across the gap, and its path is easier to alter due to the smaller interval between the two critical transition curves. The simulation results also indicate that the meridional winds over the southern region of the gap are the dominant factor determining the formation of the WBC. The dynamic mechanism influencing the transport of WBC near the gap is both Ekman transport and the blocking of Ekman transport. Ekman transport induced by northerly winds may reduce the transport of the WBC, causing the β-effect to dominate the meridional advection (promoting the penetration). Southerly winds, however, may enhance the transport of the WBC, causing the meridional advection to dominate the β-effect (promoting the leaping state). These results explain some structural features of the Kuroshio at the Luzon Strait.Using a 1.5-layer reduced-gravity nonlinear shallow-water equation model, we studied the effect of the meridional wind on the western boundary currents （WBC） at critical states with hysteresis courses. The results of the simulation indicate that the WBC is prone to penetrating into the gap under northerly winds, and its path is more difficult to alter due to the larger interval between the two critical transition curves （C1P and C1L）. For southerly winds, the WBC is prone to leaping across the gap, and its path is easier to alter due to the smaller interval between the two critical transition curves. The simulation results also indicate that the meridional winds over the southern region of the gap are the dominant factor determining the formation of the WBC. The dynamic mechanism influencing the transport of WBC near the gap is both Ekman transport and the blocking of Ekman transport. Ekman transport induced by northerly winds may reduce the transport of the WBC, causing the β-effect to dominate the meridional advection （promoting the penetration）. Southerly winds, however, may enhance the transport of the WBC, causing the meridional advection to dominate the β-effect （promoting the leaping state）. These results explain some structural features of the Kuroshio at the Luzon Strait.

关 键 词：HYSTERESIS meridional winds Luzon Strait KUROSHIO 

分 类 号：P731.2[天文地球—海洋科学] TK411.5[动力工程及工程热物理—动力机械及工程]