A Look at Amazon Basin Seasonal Dynamics with the Biophysical ...

A Large Eddy Simulation (LES) of the Boundary Layer EvolutionOver a Deforested Region of Rondonia(Brazil).Renato Ramos da Silva and Roni AvissarDuke UniversityCivil and Environmental EngineeringPO BOX 90287Durham,NC 27701 (USA)renato@duke.eduMaria Silva Dias *Pedro Leite Silva Dias *Adilson Vagner Gandu**USP - University of São PauloABSTRACTLarge Eddy Simulation (LES) is used to study the atmospheric impacts of land use changeover Rondonia (Brazil) during the wet season. Spatial distribution of land cover types for the regionwere evaluated from Landsat images and implemented into the model. Atmospheric variablesrecorded during the LBA Wet Campaign in January 1999 are used as initial conditions for themodel and to evaluate its performance. Case studies for selected days having weak winds andstrong solar radiation were chosen in order to capture possible landscape impacts on theatmosphere. The preliminary results show that the model is able to realistically represent theevolution of the boundary layer. Also, the model shows that the “fish-bone” structure of thevegetation is able to organize local convection and impact the rainfall distribution. This LESapproach is a preliminary effort to develop a reliable tool to represent and understand the impactsof land use in the Amazon on scales not yet explored. In the near future, a larger domain will becovered by the model to better represent the mesoscale features. Additionally it will help toincrease our understanding the distribution of rainfall and the transport of trace gases over theAmazon.