东北冻土区积雪深度时空变化遥感分析

积雪作为冰冻圈的重要组成部分，对地面有保温作用，在消融时又吸收热量降低地面温度，影响冻土发育，对气候的变化十分敏感。利用微波遥感数据1979-2014年逐日中国雪深长时间序列数据集，采用GIS空间分析和地学统计方法，分析了东北冻土区积雪深度的时空变化规律及其异常变化。结果表明，东北冻土区多年平均雪深为2.92 cm，年平均雪深最高值出现在岛状多年冻土区，最低值出现在季节冻土区。东北冻土区年平均积雪深度变化以减少为主，占区域面积的39.77%，减少速率为0.07 cm·（10a）^-1。东北冻土区年平均积雪深度在1986年发生突变，开始出现减少的趋势，这与气温突变年份较为吻合。受地形和气温变化影响，年平均积雪深度减少的敏感区域主要发生在岛状多年冻土区。气温是影响东北冻土区年平均积雪深度变化最主要的因素，降水量、风速、湿度、日照时数对积雪深度均有影响。季节冻土区积雪深度对气候的敏感性要大于多年冻土区。

Analyzing the spatial-temporal variations of snow depth in the Northeast China by means of remote sensing in consideration of frozen ground zonation

Snow cover is an important component of the cryosphere, which has an insulating effect on the ground. When snow melts, heat absorbing would reduce land surface temperature. Therefore, snow affects the growth of frozen ground, and is sensitive to climate change. Spatial and temporal variations of snow depth in frozen ground regions of Northeast China were analyzed by using spatial and statistics analysis function of GIS, based on the daily dataset of snow depth from 1979 to 2014. The results showed that the annual snow depth was 2.92 cm averaged from 1979 to 2014, with the maximum annual mean snow depth in the patchy permafrost regions and the minimum one in the seasonally frozen ground regions. Snow depth had decreased with the rate of 0.07 cm·(10a)^-1, and the decreased area accounting for 39.77% of the total. The annual mean snow depth mutated in 1986 and then followed a decreasing, which was in accordance with the air temperature mutation. Affected by the terrain and the air temperature changing, the reduction of annual mean snow depth and the sensitive range mainly appeared in the patchy permafrost regions. Air temperature is main controlling factor to the annual mean snow depth in Northeast China. Precipitation, wind speed, humidity and sunshine duration can also influence the depth of snow cover. The snow depth in seasonally frozen ground regions is more sensitive than that in permafrost regions.