Impact of Biomass Burning Aerosols on the Diurnal Cycle of Convective Clouds and Precipitation over a Tropical Island

This reinforced convection is due to reduced shallow precipitation in the afternoon that leads to a warm planetary boundary layer anomaly at sunset enhancing deep convection at night. Aerosol absorptive properties strongly affect local and synoptic atmospheric responses. The radiative processes of moderately absorbing aerosols tend to reduce deep convection over most regions due to local surface cooling and atmosphere warming that increase the static stability.

For more absorbing aerosols, however, the impact is reversed with increased nighttime convection over most regions. This is partly related to changes in the vertical water vapor divergence profiles that decrease the convergence toward Borneo for moderately absorbing aerosols and increase it for more absorbing ones. These changes in the synoptic circulation due to large-scale aerosol perturbations are as important as local processes to explain the observed rainfall perturbation patterns.