东南亚生物质燃烧输送影响我国西南气溶胶辐射特性研究

Study on the influence oftransport of biomass burningmaterials from Southeast Asia on aerosol radiation effects in Southwest China

利用2013年地基CE-318太阳光度计观测数据,结合中分辨率成像光谱仪(MODIS)遥感产品和HYSPLIT后向轨迹分析,研究了一次东南亚生物质燃烧污染长距离输送至中国西南昆明站点过程(2013年4月5~8日)中,气溶胶光学特性和辐射特性的变化及其可能来源.结果表明,此次污染过程期间,我国西南地区生物质燃烧活动较少,而中南半岛地区生物质燃烧活动显著.4月5~7日,昆明站点气溶胶光学厚度(AOD)升高,消光波长指数(EAE)和吸收波长指数(AAE)均增大.此外,依据EAE和AAE分类方法,5~6日昆明站点以城市工业气溶胶为主,7~8日以生物质燃烧气溶胶为主,其细模态峰值半径(0.11μm)小于5~6日(0.15μm),7日细模态粒子体积浓度峰值(约为0.16μm^3/μm^2)是5日的2倍.气溶胶直接辐射强迫(ARF)日变化结果表明4月7日气溶胶对地表的降温效应达到最大,对大气的加热作用最强.气溶胶直接辐射强迫效率值(ARFE)的变化表明生物质燃烧气溶胶对大气顶的降温作用减弱.MODIS遥感以及HYSPLIT模式后向轨迹表明,此次昆明站点生物质燃烧气溶胶主要来源于东南亚地区(主要是印度北部、印缅北部和不丹地区).

Variations in aerosol optical andradiative properties,and aerosol potential sources are examined in a case of long-distance transport of biomass burning materialsfrom Southeast Asia to Kunming site in southwest China(April 5~8,2013),based on the observational data of CE-318sun photometer in 2013,Moderate Resolution Imaging Spectroradiometer(MODIS)remote sensing products and HYSPLIT back trajectory analysis.The results showed that biomass burning activities were rare in southwest China during the pollution event,while there were a large number of biomass burning activities in Indo-China Peninsula in Southeast Asia.From April 5th to April 7th,the increasesin aerosol optical depth(AOD),extinction angstrom exponent(EAE),and absorption angstrom exponent(AAE)were observed.According to the classification methods withEAE and AAE,it was found that the Kunming sitewas mainly affectedby urban industrial aerosolduring April 5th^6th;on the contrary,biomass burning aerosol was the dominated type on April 7th and 8th.The peak radius of fine-mode(0.11μm)aerosol onApril 7th and 8th was smallerthan that on April 5th and 6th(0.15μm),and the peak concentrationof fine-mode aerosolvolume concentration(about 0.16μm3/μm2)on April 7th was twice as much as that on April 5th.The daily variation of aerosol direct radiation forcing(ARF)indicated that the most significant day for biomass burning aerosol pollution was April 7th.On April 7th,the cooling effect of aerosol on the surface temperature reached the maximum,and the heating effect on the atmosphere was the strongest.The changes of aerosol direct radiation forcing efficiency(ARFE)indicated that the cooling effect of biomass burning aerosol on the top of atmosphere was weakened.MODIS remote sensing data and HYSPLIT back trajectories showed that the biomass burning aerosols at Kunming site were mainly transported from Southeast Asia(mainly north India,northern India-Myanmar and Bhutan).