以青海省柴达尔—木里铁路、热水—江仓公路沿线两侧约10 km缓冲区为研究区域,以冻土钻孔实测数据为基础,定量分析和评价了经度、纬度、高程、太阳辐射、坡度、坡向、地面曲率等地形—候因子对沿线区域多年冻土分布的影响,建立了以经度、高程、坡度为自变量、多年冻土发生概率为因变量的Logistic模型。借助于GIS软件和DEM数据,完成了道路沿线区域多年冻土分布概率图的绘制和多年冻土分布概率的特征分析。结果表明,极可能多年冻土(概率值为0.75~1)的分布面积为1983 km2,占整个研究区域面积的65%;可能多年冻土(概率值为0.5~0.75)的分布区面积为192 km2,占研究区域面积的6%;季节冻土(概率值〈0.5)的分布区面积为894 km2,占沿线区域面积的29%。
Taking the 10km-wide buffer areas along the traffic lines,the Cetar-Muri Railway and the Reshui-Jiangcang Road,in Qinghai province as the research areas,this paper studies the distribution patterns of permafrost in the buffer area.Boreholes,which were drilled in the fields and used to determine the existence of perfamost at the drilling points,were the data basis.Based on the 189 boreholes and DEM,effects of longitude,latitude,elevation,solar radiation,aspect,slope and curvature on the distribution of permafrost were evaluated quantitatively through the correlation analysis.The results indicated that the macro-scale factors of longitude,latitude,elevation and solar radiation were the major affecting factors.As the spatial scale decreased,slope was another important factor affecting the distribution of permafrost.Therefore,a logistic model,taking longitude,elevation and slope as independent variables,and the occurrence probability of permafrost as a dependant variable,was developed to simulate the distribution probability of permafrost in the buffer areas.The modeling results showed that the possible permafrost with probability values ranging from 0.75 to 1 was the major type,accounting for 65% of the buffer area.The second largest distribution area was the seasonally frozen ground with probability values smaller than 0.5,accounting for 29% of the buffer area.The third was the possible permafrost type with probability values of 0.5-0.75,accounting for only 6% of the buffer area.