Journal of Geophysical Research,
107, C11, 3195, doi:10.1029/2001JC001005., 2002
Near-surface circulation and tidal currents of the Okhotsk Sea observed with
satellite-tracked drifters
K. I. Ohshima, M. Wakatsuchi, Y. Fukamachi, and G. Mizuta
Near-surface circulation of the Okhotsk Sea was observed with ARGOS drifters
from August 1999 to February 2000. The drifters clearly revealed the existence
of the southward boundary current (the East Sakhalin Current) off the east
Sakhalin. This current is strongly controlled by bottom topography and confined
to the region shallower than 1000 m. The volume transport of this current is
estimated to be in the range of 4–9 Sv (1 Sv = 106m3 s-1),
with the increase from summer to winter. The current appears to consist of two
cores: one exists near the coast (50–150 m depths) with typical speeds of
0.3–0.4 m s-1 and the other exists over the shelf slope (300–900 m
depths) with typical speeds of 0.2–0.3 m s-1. A part of this
southward current continues as far as the southern tip of Sakhalin Island, while
another part turns to the east around Terpeniya Bay (~48°N) flowing eastward as
far as Bussol' Strait. Most of the drifters that survived in the Okhotsk Sea
went out to the Pacific through Bussol' Strait by less than a half year,
suggesting that Bussol' Strait is the main pathway for the surface water to flow
out from the Okhotsk Sea. Mesoscale anticyclonic eddies with diameters of
100–200 km are dominant in the Kuril Basin. Diurnal shelf waves were identified
over the shelf in the northern part of the east Sakhalin shelf. Large
amplification of diurnal tidal currents (order of 1.0 m s-1) was
observed over Kashevarov Bank along with the residual anticyclonic circulation.
Both diurnal and semidiurnal tidal currents were found to be enhanced in and
around Bussol' Strait.