甘肃半干旱区城乡气溶胶光学特性的观测与分析

Observation and analysis of aerosol optical properties in urban and rural areas in semi-arid regions in Gansu Province

利用CE318型太阳光度计(532 nm波段)在2004年5月-2007年5月的城乡观测资料,反演分析了半干旱地区城乡气溶胶的光学特征.得到了气溶胶光学厚度(AOD)的年季变化,并对不同季节气溶胶的光学厚度以及波长指数的变化规律进行了讨论.结合兰州市郊区资料,对城郊大气气溶胶光学特征进行了对比及原因分析.认为较城市而言,半干旱区乡村大气总体上较城市更为洁净.城市气溶胶受到冬季采暖期等人为因素的影响,出现了AOD冬季大、夏季小的特点.气溶胶主要以工业粉尘和沙尘气溶胶为主,夜间逆温层对AOD的日变化影响较大.乡村春季沙尘天气较多,气溶胶浓度变化受季节的影响,春季AOD最大.气溶胶主控粒子多为沙尘粒子.

Based on the data of CE318-sun photometer （532 nm wave band） from May 2004 to May 2007, the aerosol optical properties in urban and rural areas of semi-arid regions were analyzed and the characteristics of optical depth and Angstrom parameters of aerosols in different seasons were discussed. A comparison between the aerosol optical properties in urban and rural areas of semi-arid regions was made： in general, the air in villages in semi-arid regions was cleaner than that in the city. The urban aerosol under the impact of human factors had a higher AOD in winter because of heating, than in summer. Major components of aerosols were industrial powders and dust particles. The inversion layer at night influenced the diurnal variation of AOD. Aerosol concentration in rural areas was more affected by sandstorms so that AOD was the highest in spring, and the major components of aerosol were dust particles.