2002年4～5月琉球群岛两侧海流的研究

The currents on both sides of the Ryukyu Islands in April and May 2002

基于日本气象厅“长风丸”调查船在2002年4～5月航次期间的CTD资料,结合卫星风场资料,采用改进逆方法计算了琉球群岛两侧海域各断面的流速和流量分布,并分析卫星跟踪浮标资料和同期的卫星高度计资料,得出下面一些主要结论:(1)黑潮流速在PN断面上只有一个流核.通过断面PN的净东北向流量约为34.7×106m3/s,此流量包括台湾暖流、东海黑潮和黑潮以东的反气旋涡的流量.(2)黑潮流速在断面TK上有两个流核,通过断面TK净东向的流量为25.6×106m3/s,黑潮通过海峡后流向断面ASUKA.(3)冲绳岛东南海区琉球海流的流量约为8.8×106m3/s,并流向断面AM.(4)奄美大岛以东的北向海流的流量为12.7×106m3/s,并流向断面ASUKA.在断面ASUKA东南部出现一个中尺度反气旋涡,直径约240 km,其流量约为28.5×106m3/s.(5)四国以南黑潮第一层水体基本来源于通过吐噶喇海峡的黑潮,第二、三层水体来自吐噶喇海峡和奄美大岛以东海域的流量大致相当,而第四层的流量则主要来自于奄美大岛以东海域.(6)浮标资料显示,奄美大岛以东的海流部分来自于断面AM以东海区,并通过断面ASUKA.

On the basis of the data obtained in cruises of April and May 2002 onboard the R/V Chofu Maru of Japan Meteorological Agency and the satellite wind data of QuikSCAT during April and May 2002, the velocity and volume transport （VT） of the currents on both sides of the Ryukyu Islands are computed by using the modified inverse method. In the meantime, analyzing the ARGOS satellite tracked drifters data in 2002 and the simultaneous sea surface height anomalies merged data of CLS AVISO, the main results are obtained as follows： （1） The Kuroshio only has one core at the Section PN. the net northeastward VT through Section PN is about 34.7 × 10^6 m^3/s, including Taiwan Warm Current, Kuroshio in the East China Sea and the anticyclonic eddy east of the Kuroshio. （2） The Kuroshio has two cores in the Tokara Strait, and its VT is about 25.6×10^6m^3/s, and then flows towards Section ASUKA. （3） In the area southeast of the Okinawa Island, VT of Ryukyu Current （RC） is about 8.8× 10^6m^3/s, and it flows towards Section AM. （4） The net VT of the northward current through the area east of the Amami-Oshima Island is about 12. 7 × 10^6m^3/s, and then flows towards Section ASUKA. There is a meso scale anticyclonic gyre at Section ASUKA, its diameter is about 240 km, and its VT is about 28.5× 10^6m^3/s. （5） The VT of Kuroshio through Section ASUKA in the first layer mostly comes from the Kuroshio in the Tokara Strait. In the second and third layers, it comes from the northward current east of the Amami-Oshima Island and the Kuroshio in the Tokara Strait, and their VTs equal approximately. （6） From analyzing the drifts＇ data, a part of current east of the Amami-Oshima Island comes from the area east of Section AM, and then it flows through Section ASUKA.