塔克拉玛干沙漠黑碳气溶胶的特性及来源

长期监测并采集塔克拉玛干沙漠腹地的大气颗粒物及黑碳气溶胶样品.在塔克拉玛干沙漠腹地,沙尘气溶胶中的黑碳在PM10中的年平均含量高达1.14%,这说明在人迹罕至的塔克拉玛干沙漠地区,其上空的沙尘气溶胶也已经受到人为活动的影响.黑碳气溶胶具有明显的季节变化和日变化,冬季最高,平均达2261.7ngm-3,依次为冬季春季秋季夏季.黑碳气溶胶日变化特征与城市地区恰好相反,夜间高于白天,午夜0:00～2:00出现峰值,而在上午8:00～11:00出现低值.非沙尘暴期间黑碳对PM10的贡献是沙尘暴时期的11倍.塔里木盆地周边绿洲带人为活动,尤其是新疆南北部地区跨越春秋冬三季的居民采暖所产生的黑碳经由局地、区域或长途传输是塔克拉玛干沙漠腹地黑碳气溶胶的主要来源,也是沙漠黑碳气溶胶具有明显的季节特征和日变化的主要原因.随着沙尘气溶胶的长途传输,沙漠每年大约输出6.3×104吨黑碳气溶胶,这势必会对全球的气候与环境变化产生一定影响.

Characteristics and source of black carbon over Taklimakan Desert

Black carbon （BC） and PM10 in the center of Taklimakan Desert were on-line monitored in the whole year of 2007.In addition,TSP samples were also synchronously daily collected by medium-volume samplers with Whatman 41 filters in spring of 2007.BC in the dust aerosol was up to 1.14% of the total mass of PM10.A remarkable seasonal variation of BC in the aerosol with the order of winterspringautumnsummer was observed.The peak value of BC appeared at midnight while the lowest in the evening each day,which was just the reverse of that in urban area.The contribution of BC to the total mass of PM10 in non-dust storm days was ～11 times of that in dust storm.Through back trajectory and principal component analysis,it was found that BC in the dust aerosol over Taklimakan desert might be attributed to the emission from the anthropogenic activities,including domestic heating,cooking,combustion of oil and natural gas,through the medium-range transport from those oases located in the margins of the desert.The total BC aerosol from Taklimakan Desert to be transported to the eastward downstream was estimated to be 6.3×104 ton yr-1.