摘要
基于日本“长风丸”调查船在2000年5个航次水文资料及同时期QuikSCAT风场资料，采用改进逆方法计算了冲绳岛东南海域海流的流速与流量等，获得了以下主要结果．（1）在琉球群岛以东海区1～2，4，7，10与11月分别为东北风，东北风，东南风，偏东风，东北风．风速在4与7月较小，1～2，10与11月较大．表层风海流只有7月时偏北向，其余月偏西方向．（2）琉球海流是琉球群岛以东一支东北向的西边界流．琉球海流结构：最大流速在5个航次中1～2，4，7，10与11月分别为40cm／s以上，15，20，20与55cm／s．琉球海流的核心一般位于次表层．琉球海流在5个航次中垂向方向可达1200m以深，在琉球海流以深存在弱的、西南向海流．（3）琉球海流的流量在1～2与11月时最大，分别为20×10^6与14．5×10m^3／s，而在4月时流量最小，只有3．1×10^6m^3／s．这表明琉球海流的流量在2000年季节变化很大．（4）在5个调查航次中，琉球海流以东调查海域都存在尺度不同的、各种冷的气旋式和暖的反气旋式涡．1～2月时，计算区域中部与东部，分别存在反气旋暖涡W1，W2和气旋式冷涡C1，C2；在4月时存在一对较强的、水平尺度都较大的、暖的反气旋涡和冷的气旋式涡，在它们中间出现南向流，它们可能组成一个偶极子等．这些表明，在5个航次中，琉球群岛以东调查海域存在各种强度不等的中尺度涡，其变化都很大．（5）琉球海流的流量受其附近各种涡的影响很大，特别是涡的强度增大时，可能减少琉球海流的流量．（6）在5个调查航次中，琉球群岛以东调查海域都存在南向流，其中11月时最大，其流量大于15×10^6m^3／s，其次在1～2月，其流量大于10×10^6m^3／s，在4月最小，流量约为3×10^6m^3／s．上述南向流的季节变化趋向与琉球海流的季节变化趋向基本一致．
On the basis of hydrographic data obtained in 5 cruises of 2000 onboad the R/V Chofu Maru and the QuikSCAT wind data during 5 cruises of 2000,the velocity and volume transport （VT） of the currents in the region southeast of Okinawa Island are computed by using the modified inverse method. The following main results have been obtained. （1） The directions of wind are NE,NE,SE,NEE,and NE,respectively,in January-February, April,July, October and November. The wind speeds and wind-driver currents both are strongest in January-February, October and November among 5 cruises of 2000, and the directions of wind-driver current are northward only in July of 2000, and are westward in other months. （2） The Ryukyu Current is a northeastward and western boundary current east of Ryukyu Islands. Its current structure in 5 cruises of 2000 has as follows. The maximum velocity of Ryukyu Current is 40 cm/s more than, 15,20,20 and 55 cm/s, respectively, in January- February, April, July, October and November. This means that its maximum velocity is most large in January-February and November among 5 cruises of 2000,and is most small in April among 5 cruises of 2000. The Ryukyu Current extends in the vertical to 1200 m more than depths during 5 cruises of 2000,and its current core is located in the subsurface layer. There is a week and southwestward current under the Ryukyu Current. （3） The net northeastward volume transport （VT） of the Ryukyu Current is maximum in January-February and November among 5 cruises of 2000, and its VT is 20 ）〈 106 and 14.5 ×10^6m^3/s, respectively, and is minimum in April with 3.1 ×10^6m^3/ s. This means that its variability of VT is very large during 5 cruises of 2000. （4） There are the various scales anticyclonic and warm eddies and cyclonic cold eddies east of the Ryukyu Current in the computed region. For example,in January- February there are the anticyclonic and warm eddies W1 and W2, and cyclonic cold eddies C1 and C2, respectively,in the middle and eastern parts of computed region. In April there are the stronger and larger scale anticyclonic warm eddy and cyclonic cold eddy, which composes dipole, and there is southward flow between them. This shows that the variability of various strength and scales warm and cold eddies are very large east of Ryukyu Islands during 5 cruises of 2000. （5） The volume transport （VT） of the Ryukyu Current is strongly influenced by eddies, especially, when the strength of eddies strengthen,the VT of the Ryukyu Current decreases probably. （6） In 5 cruises of 2000,there is southward current east of Ryukyu Islands,and its maximum VT is greater than 15×10^6m^3/s in November,and the next is in January-February with 10 ×10^6m^3/s more than, and its minimum VT is in April with 3 ×10^6m^3/s. From the above,the tendency of seasonal change of southward current agrees basically with that of the Ryukyu Current.
出处
《海洋学报》
CAS
CSCD
北大核心
2006年第3期17-28,共12页
基金
国家自然科学基金会项目(40176007)
关键词
冲绳岛东南海域海流
流速及流量
琉球海流
中尺度涡
改进逆方法
currents in the region southeast of Okinawa Island
velocities and volume transport
Ryukyu Currents
meso-scale eddies
modified inverse method
