A theoretical study of the impact of biomass-burning CCN on the dynamics of deep convective clouds with mixed phase

RAGA, GRACIELA B.; POZO, DIANA; TORRES BRIZUELA, MARCELA; NICOLINI, MATILDE

Foz do Iguaçu, Brazil

Conferencia; 8th International Conference on Southern Hemisphere Meteorology and Oceanography; 2006

American Meteorological Society

Clouds are important components of the climate system as they affect the Earth´s albedo and they participate in the hydrological cycle. One of the largest uncertaintiesin climate modeling is related to the parameterization of convective processes and, in particular, the question of how anthropogenic emissions may affect the different types of clouds is still open. Most research has been devoted to warm stratocumulus clouds, and only recently some studies incorporate changes in cirrus and mixed phase clouds. Emissions of gases and particles during biomass burning may affect the microphysics and dynamics of clouds developing near and downwind of said emissions, and some studies have suggested that precipitation may be inhibited (Ramanathan et al, 2001). Nevertheless, there have not been many studies that explore the effect that cloud condensation nuclei (CCN) originated by biomass burning may have on deep convective clouds, in which the ice phase is dominant.In this study we have introduced changes in the parameterization of the autoconversion and accretion processes in a 3-dimensional numerical model to represent the increased ambient CCN and evaluate the dynamical response and the evolution and magnitude of precipitation.