Atmosphere cleaning by heavy precipitation: quantitative assessment of aerosol washout and boundary layer recover evaluated by MPLNET lidar measurements.

The atmospheric aerosol contributes significantly to the global radiative budget of the earth-atmosphere system. Its effect on the global radiative budget is two-fold: some aerosol types warm the system while others show a cooling effect. Aerosol budgets are poorly quantified, at least in part because of uncertainties in removal processes. Wet removal and rainout processes are not well quantified by observations, nor well represented by large-scale models, yet these processes are crucial to global aerosol simulations and to the study of aerosol-cloud-precipitation interactions. In this study we show evidence of the extent to which the aerosol loading is reduced, especially in the boundary layer, as a result of precipitation using the NASA MPLNET lidar measurements in Singapore, an ideal location close to extensive biomass burning sources where heavy rainfall events are common. The analysis is complemented with ground-based (AERONET) and satellite (MODIS)sensors.