Using acoustic Doppler current profiler (ADCP) and conductivity‐temperature‐depth (CTD) data sets obtained from 1991 to 1993, volume, freshwater, and temperature transports through the Tsushima‐Korea Straits are estimated. To remove tidal currents contained in raw ADCP data, tidal currents are calculated using harmonic constants obtained by ADCP surveys from 1998 to 1999. The annual mean and range of the volume transport through the straits are 2.4 Sv (1 Sv = 106 m3/s) and 0.8 Sv, respectively. These values are consistent with those of previous studies. The annually averaged freshwater transport is 33 × 106 kg/s, which is the same as the total river discharge around the Yellow and East China Seas. This suggests that the total river discharge and freshwater transport through the Tsushima‐Korea Straits are the prominent two components in the freshwater budget, averaged annually in the Yellow and East China Seas. The annually averaged temperature transport through the Tsushima‐Korea Straits is 0.17 PW.

No abstract

All of the available hydrographic station data (temperature, salinity, dissolved oxygen, phosphate and nitrate) taken in various seasons from 1964 to 1985 are analyzed to show where the upper portion of the Japan Sea Proper Water (UJSPW) is formed and how it circulates. From vertical distributions of water properties, the Japan Sea Proper Water can be divided into an upper portion and a deep water at the σ 1 (potential density referred to 1000 db) depth of 32.05 kg m -3 surface. The UJSPW in the north of 40°N increases in dissolved oxygen contents and decreases in phosphate contents in winter, while no significant seasonal variation is seen in the south of 40°N. Initial nutrient contents calculated from relationships between AOU and nutrients on isopycnal surfaces show no significant regional difference in the Japan Sea; this suggests that the UJSPW has originated from a single water mass. From depth, dissolved oxygen and phosphate distributions on σ 1 32.03 kg m -3 surface, core thickness distribution and subsurface phosphate distribution, it is inferred that the UJSPW is formed by the wintertime convection in the region west of 136°E between 40° and 43°N, and advected into the region west of the Yamato Rise along the Continent; finally, it must enter into the Yamato Basin.

The newly formed bottom water in the Japan Sea was observed in the summer of 2001 after the severe winter 2000–2001. The new bottom water, which was observed in the northwestern Japan Sea, showed low temperature, high salinity, high dissolved oxygen and low nutrients concentration compared to the old bottom water. The distribution of the new bottom water indicates that the bottom water was formed in the south off Vladivostok, not in the northern Japan Sea north of 43°N, and was advected to the observation area. It is suggested that the formation event occurred in the late January‐early February 2001, because strong flows of faster than 8 cms−1 appeared abruptly from mid‐February 2001. This formation event may contribute not only the relaxation of the oxygen‐decreasing trend in the bottom layer but also the spin‐up of the thermohaline circulation in the Japan Sea.

No abstract