ZONALITY OF DISTRIBUTION OF PHYSICO-GEOGRAPHICAL ZONE IN CHINA
Jiang Zhongxin (The Second Institute of Railroad Survey and Design,Kunming)
With the methods of regression analysis and trend surface analysis,taking the low and high lines of dark conifer forest,premafrost low line and the snow- line of the latest glaciation in China as examples,the paper expounds the zo- nality regularity of the distribution of physico-geographical zone in China. (1)Latitude zonality obeys the mathematical model of normal frequency distribution,being approximate to descending straight line within the latitude range of China.(2)Latitude zonality shows that the elevation of physico-geographical zone rises straight with the distance to east coast line, (3)The combination of the distribution of latitude and longitude zonalities appears a plane inclining from SSW to NNE.The decline rate of the elevation of physico-geographical zone with latitude,from south to north is 54—143 meters per degree,and the rise rate of the longitude from east to west is 0,22— 0,48 meter per kilometer.The decline rate along plane dip from SSW to NNE is 0.65—1.35 meter per kilometer.(4)The second order trend surface of physico- geographical zone resembles a semiellipse-sphere inclining from the Qinghai- Xizang Plateau to northeast China,reflecting the effect of relief.(5)Physico- geographical zonation depends on the combination of hydrothermal conditions, Thus the factors influencing the zonality distribution regularity of physico- geographical zone of China are latitude zone,the distribution of oceans and land, and relief features.(6)The change rate of permofrost low line is the largest, showing the permafrost low line is most sensitive to hydrothermal conditions. The data of the snowline of the latest glaciation are dispersive,indicating that the data of cast China have more errors.