Study on aerosol optical properties and radiative effect in cloudy weather in the Guangzhou region

- Large amount of aerosols dramatically attenuated solar radiation in Guangzhou region.
- Investigated the aerosol extinction coefficient profile distribution and inverted the height of boundary layer using the lidar
- Evaluated the impact of different types of clouds on aerosol radiation effects

Currently, Guangzhou region was facing the problem of severe air pollution. Large amount of aerosols in the polluted air dramatically attenuated solar radiation. This study investigated the vertical optical properties of aerosols and inverted the height of boundary layer in the Guangzhou region using the lidar. Simultaneously, evaluated the impact of different types of clouds on aerosol radiation effects using the SBDART. The results showed that the height of the boundary layer and the surface visibility changed consistently, the average height of the boundary layer on the hazy days was only 61% of that on clear days. At the height of 2 km or lower, the aerosol extinction coefficient profile distribution decreased linearly along with height on clear days, but the haze days saw an exponential decrease. When there was haze, the changing of heating rate of atmosphere caused by the aerosol decreased from 3.72 K/d to 0.9 K/d below the height of 2 km, and the attenuation of net radiation flux at the ground surface was 97.7 W/m2, and the attenuation amplitude was 11.4%; when there were high clouds, the attenuation was 125.2 W/m2 and the attenuation amplitude was 14.6%; where there were medium cloud, the attenuation was 286.4 W/m2 and the attenuation amplitude was 33.4%. Aerosol affected mainly shortwave radiation, and affected long wave radiation very slightly.

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