辐射能量对不同深度和密度积雪持水能力及融雪水量的影响

摘要

为深入研究积雪融化过程中,积雪持水能力与融雪水量的变化特征及其影响因素,选取积雪密度、深度和辐射能量3个因素,采用室内模拟融雪试验,对试验数据进行极差分析与线性回归分析,得出辐射能量对不同积雪密度和深度积雪持水能力与融雪水量的影响规律.结果表明:积雪持水能力随密度的增大而减小.密度从100kg·m-3增大到300kg·m-3时,产流时持水能力从46.22减小到13.61,减小约3.4倍,同时产流前、后持水能力变化率也呈现减小趋势.融雪水量随积雪深度的增加而增加.深度从5cm增大到25cm,产流时融雪水量从1.58mm增大到10.70mm,增大约6.8倍.积雪深度对二者变化影响较小.辐射能量与积雪持水能力和融雪水量的相关性不显著,但对二者变化影响较为明显.积雪密度是影响持水能力的主要因素,且3种因素对积雪持水能力的影响强度分别为:积雪密度>积雪深度>辐射强度.积雪深度是影响融雪水量的主要因素,且3种因素对融雪水量的影响强度分别为:积雪深度>积雪密度>辐射强度.积雪密度与深度主要通过影响雪层间孔隙度、雪粒间毛管力以及融雪水类型而影响积雪持水能力与融雪水量.能量通过改变积雪特性进而影响积雪持水能力和融雪水量.%In order to study snow water-holding capacity and melt-water amount's characteristics and influence factors in snow melting process. The snow density, depth and radiation energy of 3 kinds of factors have been selected to simulate snowmelt in laboratory through range analysis and linear regression analysis for the test data. The results showed that snow water-holding capacity decreased with the increase of density when snow density increased from 100 kg·m-3 to 300 kg·m-3, and the water-holding capacity decreased by about 3.4 times from 46.22 to 13.61, while the changing ratio before (and after) initial runoff showed the same trend. Snowmelt water enlarged with snow depth increases. When the snow depth increased from 5cm to 25cm, the snow melt-water amount increased about 6.8 times from 1.58 mm to 10.70 mm, meanwhile the changing ratio before initial runoff increased almost 3 times. Snow density has less effect on changes of two parameters. Radiation energy was not correlated with both parameters, but correlated with their changes. So snow density was the main affecting factor of snow water-holding capacity, and the effect intensity order of the three factors on snow water-holding capacity respectively was snow density, snow depth > radiation energy. Snow depth was the main affecting factor of melt-water amount and the effect intensity of the three factors on melt-water amount severally was snow depth, snow density > radiation energy. Snow density and depth showed the obvious direct effect on snow water-holding capacity and melt-water, through changing the porosity of snow layers, capillary force of snow grains and snowmelt water types and etc. Radiation energy had indirect effect on snow water-holding capacity and melt-water amount through changing the characteristics of snow.