天津市春季气溶胶消光特征和辐射效应的数值模拟

Simulation of extinction and radiant effect of aerosol in spring of Tianjin City.

根据GRIMM气溶胶粒谱分析仪对粒子数浓度在线观测资料,拟合了天津市春季霾日和非霾日的气溶胶粒子谱分布,结合同期气溶胶样品化学组分分析结果,利用米散射理论计算分析霾日和非霾日气溶胶消光特征.在此基础上,对辐射传输模式LOWTRAN7中气溶胶光学参量进行了修正,利用修正后的模式模拟霾日和非霾日的地面辐射通量密度.结果表明,观测期间非霾日气溶胶消光系数平均为0.253km-1,散射系数平均为0.213km-1.霾日气溶胶消光系数平均为0.767km-1,散射系数平均为0.665km-1.对比模式计算的辐射通量密度与观测值,表明短波辐射模拟效果较好.

The size distribution of aerosol number concentration in haze days and non-haze days during spring in Tianjin was fitted based on the measured particle number concentrations by the Grimm instrument.According to the chemical composition of aerosol over the same period,the extinction characteristics of ambient aerosol in haze days and non-haze days were calculated using Mie theory model.The optical parameters of aerosol in the atmospheric radiation transmission model LOWTRAN7 was modified and radiant flux densities on the ground in haze days and non-haze days were simulated.The average extinction coefficient and scattering coefficient of atmospheric aerosol were 0.253km-1and 0.213 km-1 in non-haze days,while 0.767km-1and 0.665 km-1 in haze days.The model calculated shortwave radiant flux densities in haze days and non-haze days showed fairly agreement with the observation results.