上海不同强度干霾期间气溶胶垂直分布特征

利用美国宇航局(NASA)的CALIPSO星载激光雷达资料,通过分析后向散射系数、体积退偏比和色比等参量揭示了上海地区发生不同强度干霾时气溶胶的垂直分布特征,并结合地面气溶胶观测进行了分析.结果表明,发生干霾时,低层大气(2km以下)污染最严重,气溶胶的后向散射系数主要集中在0.0015~0.0035km-1×sr-1,体积退偏比集中在0~15%,色比集中在0.2~0.8;2~10km高度内,散射系数相对较小,其中2~8km的值主要集中在0.0008~0.0025 km-1×sr-1,8~10km的值则主要集中0.0008~0.0015 km-1×sr-1,气溶胶体积退偏比和色比在2~4km、4~6km、6~8km和8~10km各高度内分别集中在0~20%和0~0.6.在0~10km高度内,相对于轻微干霾和轻度干霾,中度干霾时气溶胶的散射能力和不规则性最强,粒径也最大.

Vertical distribution of aerosols during different intense dry haze periods around Shanghai

With the lidar data onboard CALIPSO satellite of National Aeronautics and Space Administration (NASA), the vertical distribution of aerosols when different intense dry haze occurred around Shanghai were revealed by analyzing the parameters including attenuated backscatter coefficient, volume depolarization ratio and total attenuated color ratio. When dry haze occurred, the lower troposphere (0~2km) was polluted most severely with the aerosols whose total attenuated backscatter coefficient concentrated in the range of 0.0015~0.0035km-1×sr-1, volume depolarization ratio and color ratio were centered at 0~15% and 0.2~0.8, respectively. Total attenuated backscatter coefficients within the other altitudes between 2 and 10 kilometers were smaller, ranging from 0.0008~0.0025km-1×sr-1 and 0.0008~0.0015 km-1×sr-1. Depolarization ratio and color ratio for four altitude ranges (2~4, 4~6, 6~8 and 8~10km above ground level) were centered at 0~20% and 0~0.6, respectively. Within the altitude range from 0 to 10 km, the aerosol scattering ability and irregularity during moderate dry haze periods was the strongest and the size of aerosols was the largest compared with slight and mild dry haze periods.