塔克拉玛干沙漠腹地黑碳气溶胶浓度

Concentration of Black Carbon in the Hinterland of the Taklimakan Desert

利用2006年3月—2007年2月塔克拉玛干沙漠腹地塔中气象站黑碳测量仪的观测数据,结合同期PM10、能见度及常规气象观测资料,分析了沙漠地区大气中黑碳气溶胶浓度的变化特征及其影响因子。结果表明:观测期间黑碳浓度小时平均值为1.81±1.58μg·m-3,日平均浓度为1.72±0.85μg·m-3,区域本底值为0.78μg·m-3;日变化呈单峰,与其他地区的双峰、三峰型不同;季节变化特征明显,春、冬季黑碳浓度较高,秋季较低,春季大量沙尘增加了气溶胶的吸收特性,黑碳测量仪观测的黑碳浓度要高于近地面大气中实际的黑碳浓度;黑碳浓度小时平均值与风速呈显著非线性相关,不同风向下黑碳浓度水平有较明显的差异,该地区黑碳浓度的变化与盛行风向上来自污染较严重地区的气团输送有关,并且受局地沙尘和排放源的影响。

The black carbon aerosol mass concentrations were continuously observed by aethalometer at Tazhong meteorological station in the hinterland of the Taklimakan Desert from March of 2006 to February of 2007,and in combining with the data of mass concentrations of PM10,visibility and the routine weather observation,the variation features of black carbon and influencing factors were analyzed in this paper.The results showed that the hourly and daily average values of black carbon concentration were 1.81±1.58 g·m-3and 1.72±0.85 g·m-3,separately,and the regional background concentration of black carbon was 0.78 g·m-3;the diurnal variation of black carbon mass concentration showed a single peak curve,which is different from the double or three peak curve in other areas;the seasonal variation of black carbon concentration was obvious,which was higher in spring and winter,lower in autumn;due to the aerosol absorption increased by heavy dust in spring,the black carbon mass concentrations observed by Aethalometer would be higher than actual values of the near surface;the hourly average black carbon concentrations were significantly non-linearly correlated with wind speed and the black carbon concentrations obviously differed in various wind directions;the local variation of the black carbon concentrations were relevant to the seriously polluted air mass transported from the prevailing wind direction,and were affected by the local dust and emission sources.