Clouds, Rain Processes and Biosphere Interaction in LBA Maria A. F. Silva Dias Department of Atmospheric Sciences University of So Paulo Brazil S T WETAMC/LBA & TRMM/LBA Jan-Feb 1999 biosphere interactions... biosphere influences on clouds different land use (forest x pasture) surface energy budget production of CCN cloud influences on biosphere rainfall, radiation budget surface energy budget budgets of trace gases and chemistry compounds Budgets and transports... Freitas et al, 2000 GOES-8 visible satellite image at 11:45 UTC March 16, 1998, showing the smoke produced by biomass burning over Roraima state. GOES-8 IR satellite image at 18:00 UTC March 18, 1998 showing the convective system at northern part of Amazon basin. CLAIRE/LBA, 1998 Freitas et al, 2000 Non-convective trajectories Convective trajectories CO 2 CO ABRACOS pasture site February 1999 Betts et al, 2001 land use/land cover and topography effects... TopographyVegetation most of the deforested area is in valleys while most of the forest is in slopes and higher terrain... RAMS (full microphysics) 2 km resolution - 7 Feb early afternoon 30 minute accumulated precip Topography and heterogeneous vegetation Flat terrain and heterogeneous vegetation Topography and homogeneous vegetation=forest (*)Average accumulated precipitation in 12 hours of simulation (*) 11.3 mm (*) 9.5 mm (*) 10.2 mm Laurent et al, 2001 Effect of topography on MCS initiation Cutrim et al, 1995 DRY SEASON First echo of the day - SPol Local time = UTC-5 hours WET SEASON, 1999 Development of the CBL Fisch et al, 2000 7 February 1999 R NET rain LE H ABRACOS- BR/EC 7 Feb 1999 Cloud features in the wet season... OUTGOING LONG WAVE RADIATION February 1999 W W W E E E WETAMC 850 hPa zonal wind from NCEP analysis 11 S - 62 W dry season transition:dry to wet Herdies, Silva Dias, 2000 SACZ - South Atlantic Convergence Zone Laurent et al, 2001 NOAA/AL Profiler at Ji-Paran DeMaria (1985): The midlatitude response to tropical heating is larger when the level of maximum diabatic heating is higher in the troposphere. Global scale implications of deep convection in the Amazon Aerosol and clouds... Summary of CCN Spectra Andreae et al, 2000 westerlies easterlies transition dry to wet season Williams, 2000 What are the sources of CCN that replenish the atmospheric reservoir after continuous rainfall? Aerosol Sources Sea spray Mineral dust Natural sulfur emissions Anthropogenic SO 2 Carbonaceous aerosols (Black and Organic C) Biomass burning Fossil fuel burning Cloud condensation nuclei in Amazonia in the wet season - primary organic aerosol - secondary organic aerosol: add soluble material (sulfates) to particles that come from elsewhere or are nucleated at cloud tops. Roberts, 2000 Andreae, 2000 Sulfate fraction Roberts et al, 2000 CCN Profile: near Santarm, Par 9 September, 18: :07 GMT Roberts et al, 2000 source of new particles at cloud top: sulfates can turn them into new CCN Direct Effects (i.e., not involving cloud) a) Backscattering of sunlight into space increased albedo cooling b) Absorption of sunlight At surface: cooling In atmosphere: warming Indirect Effects CCN concentration effect on warm clouds less CCN larger drops rainfall more CCN more droplets no rainfall from warm clouds need deep clouds ice processes rainfall and lightning more drops means larger cloud albedo effect on static stability Aerosol effects Large scale dynamics/thermodynamics is cause and aerosol concentration is effect... large scale forcing is fundamental more rain means cleaner atmosphere but... clouds models with explicit microphysics are sensitive to different CCN concentrations and rainfall simulations improve with detailed microphysics so... how are clouds during the transition from an aerosol loaded atmosphere to a clean atmosphere? Local impacts Global impacts q, c Next intensive field campaign Dry to Wet Season AMC/LBA September - October 2002 Rondnia Final remarks integrated picture of cloud evolution is a very challenging subject need more data on particular processes to understand and model the whole picture Amazon region is an ideal place to study biosphere-atmosphere interactions