HR: 16:45h
AN: B54B-04    [Abstracts]
TI: Effects of land use and climate seasonality on carbon fluxes in the Amazon: scaling from landscape to region using data from MODIS satellites and from a network of flux towers
AU: * Saleska, S R
EM: saleska@email.arizona.edu
AF: Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721 United States
AU: Mahadevan, P
EM: mahadev@fas.harvard.edu
AF: Earth and Planetary Sciences, Harvard University, Cambridge, MA 02139 United States
AU: Huete, A
EM: ahuete@Ag.arizona.edu
AF: Soil, Water and Environmental Sciences, University of Arizona, Tucson, AZ 85721 United States
AU: Cardoso, F
EM: cardoso@unir.br
AF: Fundacao Universidade Federal de Rondonia, Rua das Pedras n 7388, Ji-Parana, RO 78960-000 Brazil
AU: da Rocha, H
EM: humberto@model.iag.usp.br
AF: IAG, Universidade de Sao Paulo Rua do Matao 1226, Sao Paulo, SP 05508-900 Brazil
AU: Didan, K
EM: kamel@ag.arizona.edu
AF: Soil, Water and Environmental Sciences, University of Arizona, Tucson, AZ 85721 United States
AU: Fitzjarrald, D
EM: fitz@asrc.cestm.albany.edu
AF: Atmospheric Sciences Research Center, State University of New York, Albany, Albany, NY 12203 United States
AU: Goulden, M
EM: mgoulden@uci.edu
AF: Dept. of Earth System Science, UC Irvine, Irvine, CA 92697-3100 United States
AU: Kruijt, B
EM: Bart.Kruijt@wur.nl
AF: Wageningen University and Research, Alterra PO box 47, Wageningen, 6700AA Netherlands
AU: Manzi, A
EM: manzi@inpa.gov.br
AF: Instituto Nacional de Pesquisas da Amazonia (INPA), Av. Andre Araujo, 2936, Manaus, AM 69060-001 Brazil
AU: Miller, S
EM: sdmiller@uci.edu
AF: Atmospheric Sciences Research Center, State University of New York, Albany, Albany, NY 12203 United States
AU: Nobre, A
EM: anobre@ltid.inpe.br
AF: Instituto Nacional de Pesquisas da Amazonia (INPA), Av. Andre Araujo, 2936, Manaus, AM 69060-001 Brazil
AU: Randow, C v
EM: Celso.vonrandow@wur.nl
AF: Wageningen University and Research, Alterra PO box 47, Wageningen, 6700AA Netherlands
AU: Sakai, R
EM: sakai@asrc.cestm.albany.edu
AF: Atmospheric Sciences Research Center, State University of New York, Albany, Albany, NY 12203 United States
AU: Tota, J
EM: tota@inpa.gov.br
AF: Instituto Nacional de Pesquisas da Amazonia (INPA), Av. Andre Araujo, 2936, Manaus, AM 69060-001 Brazil
AB: We investigated large-scale seasonal and spatial patterns of Amazonian carbon fluxes, and the effects of land-use conversion thereon, by combining spatially continuous satellite data from the Terra- Moderate Resolution Imaging Spectroradiometer (MODIS) with data from a network of ground-based eddy flux towers. Four years of MODIS-derived indices (enhanced vegetation index, EVI, and land-surface water index, LSWI) showed that primary forest photosynthetic activity begins its seasonal increase in the dry season, well before onset of the wet-season, a broad pattern opposite to that predicted by ecosystem models which simulate dry-season declines in primary forest photosynthesis due to water-limitation (Huete et al, this AGU meeting). Systematic reversal in the primary forest EVI pattern was observed in areas converted to pasture, agriculture, or secondary forests, where the elimination of deep roots has likely reduced vegetation access to deep soil waters which often persist through the dry season. We used data over the same time period from flux towers at "Large-Scale Biosphere Atmosphere Experiment in Amazonia" (LBA) research sites to test the satellite-observed seasonal pattern of dry-season "green-up" at specific sites, and then used tower-derived carbon exchange at those sites to calibrate a simple empirical model parameterized with MODIS data (adapted from the vegetation photosynthesis and respiration model, VPRM, developed for mid-lattitude biomes by Mahadevan et al., this AGU meeting) to obtain basin-wide estimates of the seasonal trend of carbon fluxes, and to estimate the effect of land use changes on these trends.
DE: 0414 Biogeochemical cycles, processes, and modeling (0412, 0793, 1615, 4805, 4912)
DE: 0426 Biosphere/atmosphere interactions (0315)
DE: 0428 Carbon cycling (4806)
DE: 0438 Diel, seasonal, and annual cycles (4227)
DE: 0439 Ecosystems, structure and dynamics (4815)
SC: Biogeosciences [B]
MN: Fall Meeting 2005