日本海下層冷水の性状について

For the purpose of studying the oceanographic conditions of the cold water of the lower layers in the Japan Sea, the data of the observations which were carried out during the years from 1929 to 1941 by the research vessels Soyo-mura (Fisheries Experimental Station, Tokyo), Syunpu-mura (Marine Observatory, Kobe) and Misago-mura (Fishery Experiment Station, Husan) are taken in this report. The journals in which the original records are published are shown in Table I in Appendix A.

The factors studied in this report are the water temperature, salinity, hydrogen ion concentration, dissolved oxygen and some nutrient salts (P2O5, SiO2 and N2O5-N).

To study the vertical distribution of these factors, the mean values are computed for each layer (500 to 3000m below the surface) and for each sea-division. The Japan Sea is divided into seven sea-divisions: A(south), B(east), B'(north-east), C(central), D(north), E(west) and F(south-west). The boundaries of the divisions are shown in Text-fig. 1.

The number of the data for the 1000m layer amounts to 293 for each factor. For each factor the frequency，mean value，maximum and minimum value and amplitude are shown for separate sea-divisions and the results for different divisions are compared with one another. Al1 these results are shown in Appendix A.

It is recognized that the vertical distributions of most of the studied factors somewhat differ in the northern cold water zone and in the southern warm current area. When the vertical distribution of these factors in one sea-division is compared with that in another sea-division，however，differences are seldom distinct or characteristic.