Abstract
The author's intention is to investigate the variation of hydrographic conditions in the sea region of the Ocean Weather Station “ Extra ” (39°N,153°E) from the standpoint of heat balance.
The heat exchange between sea and atmosphere, also, is examined for the same region, which examination is necessary for carrying out the said intention. The main results obtained are summarized as follows:
1) The evaporation from the sea surface, the “ BOWEN ratio ”, the sensible heat given to the atmosphere, and the total energy loss from the sea surface have all a similar type of seasonal variation, with larger values in winter and smaller ones in summer.
2) On an annual average, the amount of hea t brought into the region of St. “ Extra ” by ocean currents is comparable to the amount of heat used for evaporation which is about twice as large as the effective radiation, and plays the most important part in the heat balance. Of course, the relations are different for the seasonal and the monthly values.
3) St. “Extra”, when compared with another Ocean Weather Station “ Tango ” (29°N,135°E) on the Sea adjacent to Japan, is characterized, in general, by a little lower evaporation, much greater sensible heat exchange, and, in annual mean, greater total energy exchange.
4) The most important conclusion as to the seasonal variation of hydrographic conditions is that the Kuroshio water is ordinarily prevalent in the region of St. “ Extra ” from spring to autumn, while in winter a water mass of Oyashio origin predominantly flows into this region.
