IUGG 2003 Abstract
P01-Posters
Western Boundary Currents
Thursday, July 3 AM
Location: Site D
Presiding Chair:A.R. Piola
TIME [ 0830-251 ] [ P01/03A/D-011 ] [ Poster ]
MOORED ADCP MEASUREMENT OF VELOCITY STRUCTURES OF THE KUROSHIO AND COASTAL CYCLONIC EDDIES SOUTH OF JAPAN
Muneyuki TAKEUCHI(Department of Earth System Science and Technology, Interdisciplinary Graduate School of Engineering Sciences, Kyushu University)
Shiro IMAWAKI(Research Institute for Applied Mechanics, Kyushu University)
Shin-ichiro UMATANI ( Research Institute for Applied Mechanics, Kyushu University )
Katsuhisa YAMADA ( Matsuda Motor Corporation )
Hiroshi UCHIDA ( Japan Marine Science and Technology Center )
Masao FUKASAWA ( Japan Marine Science and Technology Center )
The data of upward-looking acoustic Doppler current profilers (ADCPs) moored at two stations (CM02 and CM04) off Shikoku during 1993-1995 are analyzed to study velocity structure of the Kuroshio region. The ADCPs measured velocities of the strong current of the Kuroshio when the Kuroshio took the near-shore path and velocities of coastal cyclonic eddies when the Kuroshio took the offshore path. The vertical profile of velocity of the Kuroshio averaged over periods of the near-shore path at CM02 shows following features: a strong current (over 100 cm/s) exists at a depth of shallower than 300 m;there is a very strong vertical shear of velocity, reaching 1.5×10^-2 /sec, from 300 to 400 m depth;and there is a weak countercurrent below 450 m depth. The vertical profile of velocity of the Kuroshio at CM04 shows strong current (over 80 cm/s) at 400 m depth, but a weaker vertical shear of velocity. These results indicate that the thermocline is thin and steep at CM02 and broader and gentle at CM04. At CM02, there is a delay of the velocity fluctuation (about 2 days) at 400 m depth compared with 300 m depth. During periods of the offshore path, the Kuroshio was accompanied by cyclonic eddies on the coastal side. The average vertical profile of velocity of these eddies shows a southwestward current, reaching 20 cm/s, at CM02 with almost no vertical shear of velocity between 300 and 500 m.At CM04, the features of current profile are similar to those at CM02 but velocities are weak(less than 10cm/s).