Density of drifters distribution (with their deployment scheme taken into account) demonstrates probable divergence in KE/SF interfrontal zone (Figs. 1a, b) and convergence (Fig. 7) in the region considered to be a source area for Tropical Mode Water. The later can be also influenced by flow interaction with South Honshu Ridge.
Finally, drifters can display the preference of specific motions in some areas. For instance, Fig. 1b reveals higher variability of the eastern slopes of KE meanders and their southern points are used by drifters for their excursions between KE and central STG.
Fig. 5 produces impression of some meridional periodicity of zonal flows with eastward KE and SF jets and westward countercurrent between them, KE recirculatlon and, possibly, SF recirculation in the north. Similar periodicity can be found in Fig. 8, containing all drifter fragments in STG with eastward propagation component. Although this structure is rather dummy, qualitatively similar feature can be also found in trajectories (Fig. 9) of 1000m deep RAFOS floats. Being poorly provided with data at present, still this may be a demonstration of gap in our knowledge about basic physical mechanisms governing large-scale oceanic circulation. One of byproducts of our investigation is the recognition of high quality of WOCE SVP standard drifter data and their importance and efficiency for physical oceanography.
References
[1] World Ocean Circulation Experiment implementation plan. Volume 1: Detailed requirements, 988, WMO World Climate Research Programme, WCRP-11 , WOCE International Planning Offrce, WOCE Report 20/88 (WMO/TD-NO. 242), 63pp.
[2] D. V. Hansen and P. -M. Poulain, 1996. Quality control and interpolation of WOCE-TOGA drifter data, J. Atmos. Oceanic Technol., 13, 900-909.
[3] S. Aoki, S. Imawaki and K. Ichikawa, 1995, Baroclinic disturbances propagating westward in the Kuroshio Extension region as seen by satellite altimeter and radiometers, J. Geophys.Res., 100, 839-855.
[4] A. S. Vasilev and V. P. Makashin, 1993, Mesoscale dynamic structure of Subarctic frontal zone in the Pacific, Meteorology and Hydrology, 4, 60-68.
