拉萨和日喀则地区雪-冰表面吸光性物质特征及其影响因子分析

Characteristics and influence factors analysis of light-absorbing substances on snow-ice surface of Lhasa and Shigatse areas

雪-冰表面吸光性物质可加速冰川消融。研究了拉萨和日喀则地区雪-冰表面吸光性物质(黑碳(BC)和有机碳(OC))的分布特征、污染来源及其影响因子。结果表明:研究区域内雪-冰中BC和OC的质量浓度分别为5~157、26~243 ng/g,平均质量浓度分别为48、97 ng/g;日喀则地区的BC和OC的质量浓度分别为(25±16)、(62±28)ng/g;拉萨地区的BC和OC的质量浓度分别为(71±43)、(132±62)ng/g。通过对吸光性物质的影响因子分析发现:冬春季节,南亚和中亚等地区的污染物随气流的远距离传输对研究区域的污染贡献较大;吸光性物质随海拔升高呈现出递减趋势;不同土地利用类型中BC含量大小分布依次为:郊区用地>建设用地>农田用地>牧区用地,OC含量大小分布依次为:郊区用地>农田用地>建设用地>牧区用地。

The light-absorbing substances(LASs)on the snow-ice surface accelerates the melting of glaciers.The distribution characteristics,pollution sources and influence factors of LASs(namely black carbon(BC)and organic carbon(OC))on snow-ice surface of Lhasa and Shigatse areas were analyzed.Results showed that the mass concentrations of BC and OC in snow-ice in study area were 5-157 and 26-243 ng/g,respectively;the average mass concentrations were 48 and 97 ng/g,respectively.The mass concentrations of BC and OC in Shigatse were(25±16)and(62±28)ng/g,respectively.The mass concentrations of BC and OC in Lhasa were(71±43)and(132±62)ng/g,respectively.Based on the analysis of the influencing factors of LASs,it was concluded that in winter and spring,the long-distance transmission of pollutants along with airflow in south Asia and central Asia contributed a lot to the pollution in the study area.The LASs showed a decreasing trend with the increasing altitude.BC in different land types were in order of suburban land>construction land>farm land>grazing land while OC was suburban land>farm land>construction land>grazing land.