Abstract
It is well known that the coastal belt of the continent corresponds to the dividing line of the climate. This subject is discussed from the viewpoint of air-mass mixing and transformation, and the following lines are attacked;
(1): Spatial distributions of the diurnal variability of daily mean pressure (Fig. 1 and 2) and the standard deviation of yearly change of the monthly mean pressure (Fig. 4) are examined with the results along the trough line of these distributions. The transportation of air-mass is smaller than that of other regions. Using these results, the fields of wind and precipitation is divided into two parts.
(2): Spatial distributions of the interdiurnal variabilty of daily mean temperature (Fig.5) and the standard deviation of year to year change of monthly mean temperature (Fig.6) are studied. Trough line of the latter distribution corresponds to the frontal zone (Fig.7). or locates between the zones of high and low temperature. These results are explainable as the products of the air-mass mixing and transformation during its long journey.
Thus, it is shown that the classification of climate by trough line of the standard deviation of monthly mean temperature is much useful from the view-point of air-mass mixing and transformation.
(3): Spatial distribution of the standard deviation of year to year variation of monthly mean vapour pressure is also studied. (Fig.8) Trough lire of this distribution means the dividing line of precipitation variability.(Fig.9)
(4): Using the obtained results, climate near Japan is classified from the view-point of air-mass mixing and transformation.
Two examples are as follows:
(a): Winter air temperature over Japan is controlled by the air-mass over Siberian continent although the wind velocity blowing over Japan is affected by the depth of Aleutian Low, although the amount of precipitation is completely under the influence of the Sea of Japan.
(b): In summer, the air temperature over Japan is affected principally by the temperature off the coast of Sanriku although the wind velocity proportional to the strength of Ogasawara High. Precipitation over Japan is influenced by the intensity of Ogasawara High along the southern coast, and is affected by the climatic condition off the coast of Sanriku.
