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积雪中存在的吸光性污染物对积雪反射率具有显著的降低作用,进而对能量平衡和气候变化有重要影响.但是,污染浓度变化如何影响积雪反射特征仍然缺乏定量描述和深入探讨.选择新疆富蕴作为典型干旱与半干旱积雪实验区,通过人工控制试验在自然积雪状态下生成不同浓度的污染雪样方,并对积雪及污染物自身的反射率进行测量.在实测数据基础上通过构建线性混合模型定量分析不同浓度条件下污染物对积雪反射率的影响力.研究结果表明:积雪反射率降低与污染浓度呈非线性关系,随着污染浓度增大,单位浓度影响力降低,在350~450 nm波段范围1813 ppm浓度的单位影响力甚至是9 507 ppm浓度的1.5倍以上;同时发现除了污染浓度,积雪与污染物自身物理特性也是影响反射率变化的重要参数.“,”Light-absorbing particulate pollutants in snow decrease snow reflectance significantly bring important effects on energy balance and climate change.The reduction of snow reflectance due to pollutants is an important and active research topic.In this study,a controlled experiment was carried out to measure the spectral reflectance of snow,in which the different synthetic pollutant amount was added.The study area is located in Fuyun county of Xinjiang Province where the seasonal snow area is representative of arid and semiarid region,and the spectral reflectance of the snow pollutant used in our experiment was also measured.The impacts of the pollutant with different concentrations on snow reflectance were analyzed quantitatively by building a linear mixing model using measurements.The results show that the relationship between reduction of snow reflectance and the pollutant concentration was nonlinear.As total pollutant concentration increased,the impact of 1 ppm(parts per million)pollutant on snow reflectance decreased.In experiment,the impact decreased by more than one-third when the concentration increased from 1 813 ppm to 9 507 ppm.Moreover,this study found that the physical characteristics(such as grain size and shape)of snow and pollutants also played important role in the variation of dirty snow reflectance besides of the pollutant concentration.