中国北方气溶胶散射和PM10浓度特征

利用积分浊度计和PM10浓度监测仪,对中国北方2005年观测的气溶胶散射系数σsp与可吸入颗粒物PM10质量浓度的分析表明,张北站σsp年均值为130 Mm-1,民勤站σsp年均值为116 Mm-1;四季中都是冬季均值最高,张北站sσp为301.6 Mm-1,民勤站σsp为170.9 Mm-1,这说明张北站的气溶胶散射情况比民勤站显著。而PM10浓度反映了不同的变化规律,张北站PM10年均值为53μg.m-3,民勤站PM10年均值为130μg.m-3;四季中都是春季均值最高,张北站PM10为82.2μg.m-3,民勤站PM10为190.1μg.m-3,这说明民勤站的PM10污染比张北站严重很多。张北站的质量散射效率α年均值为2.4 m2.g-1,民勤站的α年均值为1.1 m2.g-1,这与张北站全年主要受城市污染型气溶胶的影响,而民勤站全年主要受沙尘气溶胶的影响有密切关系。α具有反映中国北方两种典型气溶胶的能力。     

Surface aerosol measurements at Barrow during AGASP-II

Measurements at Barrow during the second Arctic Gas and Aerosol Sampling Program (AGASP-II), conducted in April 1986, showed no rapid long-range transport from lower-latitude source regions to Barrow, and only limited vertical transport from above the boundary layer to the surface. New aerosol size distribution measurements in the 0.005–0.1 m diameter size range using a Nuclepore-filter diffusion battery apparatus showed a median diameter of about 0.01 m during times of high condensation nucleus (CN) concentrations. Aerosol black carbon concentrations exceeding 400 ng m^–3 were detected at the surface and were more strongly correlated with CN concentrations than with aerosol scattering extinction (_sp), suggesting that aerosol carbon was generally associated with small particles rather than large particles. Measurements at Barrow during AGASP-I, conducted in March–April 1983, showed a series of aerosol events detected at the ground that were caused by rapid long-range transport paths to the vicinity of Barrow from Eurasia. These events were strongly correlated with aerosol loading in the vertical column (optical depth).