HR: 16:00h
AN: B52E-01    [PDF]
TI: The Influences of Fresh Water co2 Effluxes and Mesoscale Circulations on Regional Carbon Balance in the Tapajos Region, Para, Brazil
AU: * Lu, L
EM: lixin@atmos.colostate.edu
AF: Department of Atmospheric Sciences, Colorado State University, Fort Collins, CO 80523 United States
AU: Denning, S A
EM: denning@atmos.colostate.edu
AF: Department of Atmospheric Sciences, Colorado State University, Fort Collins, CO 80523 United States
AU: Silva-Diaz, P d
EM: pldsdias@model.iag.usp.br
AF: Department of Atmospheric Sciences, University of Sao Paulo, Sao Paulo, SP 99999 Brazil
AU: Silva-Diaz, M A
EM: mafdsdia@model.iag.usp.br
AF: Department of Atmospheric Sciences, University of Sao Paulo, Sao Paulo, SP 99999 Brazil
AU: Inazawa, E
EM: elicia@lamar.colostate.edu
AF: Department of Atmospheric Sciences, Colorado State University, Fort Collins, CO 80523 United States
AB: We have investigated mesoscale variations of atmospheric co2 over a heterogeneous landscape of forests, pastures, and large rivers during Santarem Mesoscale Campaign (SMC) during August 2001. We simulated the variations of surface fluxes and atmospheric concentration of co2 using the CSU Regional Atmospheric Modeling System (RAMS) on 4-level nested grids which including a 1-km finest grid centered on the Flona Tapajos. Surface fluxes of co2 were prescribed in the model using idealized diurnal cycles over forest and pasture vegetation, and over surface water using a value suggested by in-situ measurements in the Amazon River. Heterogeneous vegetation types were derived from the 1-km International Geosphere-Biosphere Programme (IGBP) land-cover dataset version 2.0. Our simulation ran from 1 through 15 August 2001, which was concurrent with our SMC. The results demonstrated that the local topography, the roughness length, the "T" shape juxtaposition of Amazon and Tapajos Rivers, and the resulting horizontal and vertical wind shears, all facilited the generation of local mesoscale circulations. The explanation for the mechanisms producing the lower level convergence line on the east bank of Tapajos River during the strong trade-wind days will also be presented. Meanwhile, we investigated the effects of surface water co2 effluxes on the regional carbon balance. The simulations with and without specifying co2 fluxes from the rivers and inundated land were performed. The result demonstrated that surface water co2 fluxes modify simulated co2 concentrations, especially at night. We are currently collecting and processing SMC measurement data, and hope that our modeling study can help the interpretation of [co2] distribution observed by towers and light aircraft.
DE: 0315 Biosphere/atmosphere interactions
DE: 0400 Biogeosciences
DE: 1610 Atmosphere (0315, 0325)
DE: 1620 Climate dynamics (3309)
DE: 1833 Hydroclimatology
SC: Biogeosciences [B]
MN: 2003 Fall Meeting