TREND SURFACE ANALYSIS OF THE EXISTENT SNOWLINE IN WEST CHINA
Jiang Zhongxin ( The Second Institute of Railroad Survey and Design, Kunming 650000,PRC)
The analysis of twenty five existent snowline elevation values in West China indicates that snowline elevationH (meter) presents zonality change declining from south to north with latitude φ(degree) and the change declining from west to east with longitude which relates to the distance L (kilometer) to the east coastline. Therefore, the first order trend surface equation of the snowline in West China shows a plane incline from southwest to northeast. The second order trend surface equation of the snowline in West China truly represents the distribution law of the snowline in West China. Its form resembles a "overturned anticline" from southwest to northeast. The "raised axis" seems to be superimposed upon the first order trend surface.It reflects the effect of the relief. The snowline elevation in West China depends on horizontal zonality,distribution of ocean and land,and the relief.