凍結期間における若干の気侯値の推定
1969 年 21 巻 3 号 p. 123-128
詳細
1969 年 21 巻 3 号 p. 123-128
The purpose of the author is to obtain the method to estimate the several climatic values based on the average monthly air temperature. For this purpose, the author investigated the relation between the air temperature and several climatic values, using the climatic data of meteorological offices in Japan. The results are as follows ;
1) The relation between the average monthly minimum air temperature and the number of days under 0°C (Fig. 1), the length of the period under 0°C (Fig. 2) or the average calendar-day at the end of the freezing season (Fig. 4) can be shown by the tendency curve with little deviations.
2) The average calendar-day leaving 0°C in minimum air temperature in spring (the end of freezing season) is closely related to the number of days under 0°C. Using the Fig. 6 showing the relation in each month, the author obtained Fig. 7, by which the number of freezing days after that day can be estimated.
3) Regarding the minimum air temperature, the number of days under 0°C at 1.5 meter level is not always closely related to it near the ground (Fig. 8). But the deviations from the tendency-curve show the relation form a geographical pattern (Fig. 9).
4) The relations between the average calendar-day with last-frost and the average monthly minimum air temperature are known (Fig. 10). From the figure the retarding-rate of the former per 1°C in the latter can be estimated as shown in Fig. 11. And the distribution of the climatic last-frost day will be obtained in micro-pattern corresponding to the distribution of average minimum air temperature.
