Based on the Results of Marine Meteorological and Oceanographical Observations (1966∼1987), the phenomenon of chimney is found as a candidate for the formation of the Japan Sea Proper Water (JSPW). The chimney phenomenon occurs twelve times during 1966∼1987. The water types in the chimney denoting the deep convection are similar to those of the JSPW, 0∼1 ℃ in potential temperature, 34.0∼34.1‰ % in salinity and 68∼80 cl/t in potential thermosteric anomaly from the sea surface to the deep layer. The static stabilities in the chimney stations are unstable or neutral. This indicates that the winter time convection occurs. The JSPW sunken from the surface layer of chimney in winter spreads out under the Tsushima Warm Current area, following the isosteric surface of about. 76 cl/t in potential therniosteric anomaly. The formation of the deep water of the JSPW is mainly affected by the cooling of the sea surface than the evaporation of winds because the temperature and the salinity on the isoteric surface of about 76 cl/t in potential thermosteric anomaly are cold and low. The phenomenon of chimney occurred in here and there of the area in the north of 40˚ 30` N, west of 138°E. This suggests that the deep water of the JSPW is formed not in a limited area but. probably in the overall region of the northern open ocean.

Based on the Results of Marine Meteorological and Oceanographical Observations (1966∼1987), oceanographic conditions of the Japan Sea in winter was studied in relation to the Japan Sea Proper Water (JSPW). The mean and dispersion of the deep water above 1000m depth are O.26±0.2℃ in temperature and 5.1±0.25 ㎖/ℓ in oxygen. The mean and dispersion of the bottom water below 1000m depth are 0.07±0.04℃ in temperature and 5.1±0.15㎖/ℓ in oxygen. The distributions of the temperature and dissolved oxygen in the deep water above 1000m depth are ranged wider than those of the bottom water below 1000m depth in T-S and T-O_2 diagrams. The bottom water are showed more homogeneous and smaller variations than the deep water in the characteristics of water mass. The deep water above 1000m depth is active in contact with the atmosphere. The JSPW similar to the above characteristics is showed in the open ocean of the north of 40°30` N, west of 138°E. Therefore, the deep water is formed probably by the open-ocean convection.

Based on the Results of Marine Meteorological and Oceanographical Observations during 1966∼1987 and the Ten-day Marine Report during 1970∼1989 by Japan Meteorological Agency, the possible area where the Japan Sea Proper Water (JSPW) can be formed is investigated by analyzing the distribution of water types in the Japan Sea. The Japan Sea can be divided into three subareas of Northern Cold Water(NCW), Polar Front(PF) and Tsushima Warm Current (TWC) by the Polar Front identified by a 6℃ isothermal line at the sea surface in winter. Mean position of the Polar Front is approximately parallel to the latitude 39∼40°N. The standard deviation of the Polar Front from the mean position of about 130㎞ width is the smallest in the region between 136°E and 138°E where the Polar Front is very stable, because the branches of the Tsushima Current are converging in this region. However, standard deviations are about 180∼250㎞ near the Korean peninsula and the Tsugaru Strait due to greater variability of warm currents. In the NCW area north of 40°30`N and west of 138°E, the water types of the sea surface to the 100m depth are similar to those of the JSPW. This fact indicates that the surface layer of the NCW area is the possible region of the JSPW formation in winter.