FORMATION OF 26.8-26.9 SIGMA(THETA) WATER IN THE KURIL BASIN OF THE SEA OF OKHOTSK AS A POSSIBLE ORIGIN OF NORTH PACIFIC INTERMEDIATE WATER

By using all Japanese hydrographic data obtained south of 55 degrees N in latitude in the Sea of Okhotsk, we compile a data set for this stu dy. Our investigations with these data show that a large quantity of r elatively cold, fresh, oxygen-rich homogeneous intermediate water with a density range of 26.8 to 26.9 sigma(theta) exists in the Kuril Basi n; we name this intermediate water the Kuril Basin Intermediate Water (KBIW). Results of isosteric analyses show that a possible origin of K BIW is located in a region off the Hokkaido coast in the southwestern Sea of Okhotsk. We suggest that KBIW is produced by the isopycnal mixi ng of relatively dense Soya Warm Water, which appears only in early sp ring, with the colder, fresher water which originates from the northwe stern Okhotsk. Finally, we demonstrate that KBIW may be a source water of the North Pacific Intermediate Water (NPIW) because it has the sam e density range and water properties.