Impact of biomass burning aerosols on precipitation in the Amazon: A modeling case study Export

@article{citeulike:3979144, abstract = {A study of the potential role of aerosols in modifying clouds and precipitation is presented using a numerical atmospheric model. Measurements of cloud condensation nuclei (CCN) and cloud size distribution properties taken in the southwestern Amazon region during the transition from dry to wet seasons were used as guidelines to define the microphysical parameters for the simulations. Numerical simulations were carried out using the Brazilian Development on Regional Atmospheric Modeling System, and the results presented considerable sensitivity to changes in these parameters. High CCN concentrations, typical of polluted days, were found to result in increases or decreases in total precipitation, depending on the level of pollution used as a reference, showing a complexity that parallels the aerosol-precipitation interaction. Our results show that on the grids evaluated, higher CCN concentrations reduced low-to-moderate rainfall rates and increased high rainfall rates. The principal consequence of the increased pollution was a change from a warm to a cold rain process, which affected the maximum and overall mean accumulated precipitation. Under polluted conditions, cloud cover diminished, allowing greater amounts of solar radiation to reach the surface. Aerosol absorption of radiation in the lower layers of the atmosphere delayed convective evolution but produced higher maximum rainfall rates due to increased instability. In addition, the intensity of the surface sensible heat flux, as well as that of the latent heat flux, was reduced by the lower temperature difference between surface and air, producing greater energy stores at the surface. }, author = {Martins, J. A. and Dias, Silva M. A. F. and Gon\&\#231;alves, F. L. T.}, citeulike-article-id = {3979144}, citeulike-linkout-0 = {http://www.agu.org/pubs/crossref/2009/2007JD009587.shtml}, citeulike-linkout-1 = {http://dx.doi.org/10.1029/2007JD009587}, day = {29}, doi = {10.1029/2007JD009587}, issn = {0148-0227}, journal = {Journal of Geophysical Research - Atmospheres}, keywords = {aerosol, amazon, biomass, burning, climate, model, precipitation, regional, soot, vegetation}, month = {January}, number = {D2}, pages = {D02207+}, posted-at = {2009-01-29 15:09:33}, priority = {2}, title = {Impact of biomass burning aerosols on precipitation in the Amazon: A modeling case study}, url = {http://dx.doi.org/10.1029/2007JD009587}, volume = {114}, year = {2009} }

TY - JOUR ID - citeulike:3979144 L3 - citeulike-article-id:3979144 N2 - A study of the potential role of aerosols in modifying clouds and precipitation is presented using a numerical atmospheric model. Measurements of cloud condensation nuclei (CCN) and cloud size distribution properties taken in the southwestern Amazon region during the transition from dry to wet seasons were used as guidelines to define the microphysical parameters for the simulations. Numerical simulations were carried out using the Brazilian Development on Regional Atmospheric Modeling System, and the results presented considerable sensitivity to changes in these parameters. High CCN concentrations, typical of polluted days, were found to result in increases or decreases in total precipitation, depending on the level of pollution used as a reference, showing a complexity that parallels the aerosol-precipitation interaction. Our results show that on the grids evaluated, higher CCN concentrations reduced low-to-moderate rainfall rates and increased high rainfall rates. The principal consequence of the increased pollution was a change from a warm to a cold rain process, which affected the maximum and overall mean accumulated precipitation. Under polluted conditions, cloud cover diminished, allowing greater amounts of solar radiation to reach the surface. Aerosol absorption of radiation in the lower layers of the atmosphere delayed convective evolution but produced higher maximum rainfall rates due to increased instability. In addition, the intensity of the surface sensible heat flux, as well as that of the latent heat flux, was reduced by the lower temperature difference between surface and air, producing greater energy stores at the surface. IS - D2 JF - Journal of Geophysical Research - Atmospheres SN - 0148-0227 TI - Impact of biomass burning aerosols on precipitation in the Amazon: A modeling case study VL - 114 SP - D02207 KW - aerosol KW - amazon KW - biomass KW - burning KW - climate KW - model KW - precipitation KW - regional KW - soot KW - vegetation AU - Martins, JA AU - Dias, Silva AU - Gonçalves, FLT PY - 2009/01/29/ UR - http://dx.doi.org/10.1029/2007JD009587 ER -