石羊河流域祁连山区基于地形因子的降水面域化处理

利用祁连山西段北坡34个观测站点29年的实测平均降水量,从30m、90m、1km、2km、5km、7.5km、10km 7种分辨率DEM中提取坡度、坡向、局部最大高程、局部最小高程、局部平均高程、局部高差等地形因子,分析不同分辨率下地形因子与降水的相关性,并利用多项式回归+残差插值法进行降水面域化处理.结果表明,最佳DEM分辨率是2km,插值结果百分比误差在10%以内.降水随海拔升高而线性递增,递增速率为18mm/100m,最大降水高度点海拔在3 400m左右,降水量最大达到853mm/a,是地形抬升及"狭管效应"共同作用的结果.

Modeling of Precipitation Distribution Based on Topographic Factors of Qilian Mountains in Shiyang River Basin

Based on the mean annual rainfall of 29 years obtained at the 34 observation sites on the north slope of western Qilian mountain, the topographic factors such as gradient, aspect, local maximum elevation,local minimum elevation,local mean elevation,local relief, etc. were respectively extracted from the seven-scale resolution DEM at 30 m,90 m, 1 km,2 km,5 km,7.5 kin,and 10 kin,to analyze the correlation between topographic factors and pre- cipitation,and model the area rainfall distribution by using the polynomial regression and residual interpolation method. The results show that 2 km is the best resolution with average error of the interpolation result less than 10%. With the increase of altitude, rainfall linearly increases and the increasing velocity is 18 mm/100m. The opti- mal altitude for heaviest rainfall is about 3 400 m and the highest precipitation is 853 ram/a, which is the result from the joint action of orographic uplift and funneling.