On the Stepped Character of Seasonal Change

Abstract

The way in which weather elements such as temperature change with the seasonal march is not continuous as may be suggested from the change of sun's altitude but is discontinuous as shown in Fig. 1.
The present study is made in an attempt to confirm this fact. From the features as shown in Fig. 4 and other evidences the following conclusions are reached
1. Independent from topography, latitude and the climatic change, there exist definite temperature limits as given in Table 3. In each season, temperature change of any place is confined statistically within a range called a ″step″ which is defined by a pair of such temperature limits.
2. The conventional season shall be divided into smaller parts, each of which may be called a ″sub-season ″. The sub-season is limited by one step or adjacent two steps. Then the construction of such sub-seasons and the mechanism of their succession are studied based on Fig. 7 and other evidences. However, it is found that they cannot be explained by the condition of pressure pattern and the air-mass theory. Furthermore, some questions arise on the air-mass theory itself.
As is seen in Fig. 8, there exists a high correlation between the location of the stationary front in summer and the temperature limit. This suggests that the profile of zonal current is related closely to the sub-season. But this relation is not functional ; the change of subseason in a year takes place more frequently than that of zonal current. In view of the results of the present study, it is pointed out that the stepped character of seasonal change is not a phenomenon to be explained simply by the existing concepts but includes a number of problems that need further examination.