THEORETICAL ANALYSIS OF PHYSICO-GEOGRAPHICAL ZONATION
Niu Wenyuan(Institute of Geography, Academia Sinica)
The essential reason why there is physico-geographical zonation is the regular dis- tribution of solar radiant energy on the surface of the earth as a sphere. With various humidity conditions and different altitude above the sea level, realistic situation of the earth's surface ean change the theoretical distribution pattern of physico-geographical zonation. In the present article the author have used data of the snow line, the soil line and the tree line at the different latitude in the northern hemisphere. Based on the analysis of these data, we have already set a basic theoretical model of the phywico-geographical zonation to deseribe quantitatively the ideal relationship between the horizontal zone and the vertical zone on the earth surface. It is where Vi-the spaee occupied by the same physico-geographical zone in three dimen- sions, L—the longitudinal direction, in which L and L360 express the starting and the terminal points of calculation respectively, φ—the geographical latitude, f(φ)-func- tional relation between the altitude above sea level (H) and the latitude that is where a and b are constants, i=1,2,3...... according to different physico-geographical zone. In the model, both the horizontal and the vertical zones have been connected close- ly. Besides, we have discussed the influence of humidity condition on the theoretical model.