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CD-35 Abstract

Fluxes and Budgets of CO2 and H2O in the Amazon Basin

Paulo Artaxo — USP - Universidade de Sao Paulo (SA-PI)
Plínio Barbosa de Camargo — USP - Universidade de Sao Paulo (SA-PI)
Maria Assunção Faus da Silva Dias — IAG/USP (SA-PI)
Steven Charles Wofsy — Harvard University (US-PI)

We will undertake synthesis and modeling to understand regional carbon and H2O budgets in the Amazon Basin, using data from the Tapajós primary forest site (km 67) and from the LBA-Air-ECO mission (BARCA: Balanço Atmosférico Regional do Carbono na Amazônia; collaborator, P. Artaxo, Oct. 2005). We will also prepare final and value-added data products, and will lead synthesis of regional C budgets for BARCA.

We will conduct synthesis and integration of LBA results Carbon dynamics: (a) Primary forest data: We have 4 yrs of environmental and CO2 flux data and 6 yrs of forest ecological data in FLONA Tapajós. We observed unexpected forest structure, seasonal fluxes of CO2 reversed in phase from model predictions, and a shift of the ecosystem carbon budget from a source to a sink. We will determine the underlying ecological mechanisms by detailed analysis of the observations. We will link our site data to regional carbon balance using the vegetation components of climate models, run using our data for environmental drivers. Model responses will be tested, model design updated, and implications explored. We will constrain the parameters of an empirical regional-scale carbon flux model using flux data from the full suite of LBA towers combined with MODIS data. (b) BARCA aircraft data: We will determine Basin-wide carbon balance by direct measurement, deriving the Lagrangian adjoint of a coupled climate-vegetation model that assimilates aircraft data for CO2, CO, and CH4, remote sensing, ground station data, RAMS meteorological fields, MODIS reflectances (MOD09), and GOES sunlight. The results will then be used to test and refine several ecosystem models that are currently or prospectively coupled to climate models.

Future trajectories for change: We will link LBA tower fluxes to forecasts of vegetation change under future climate. First we will assess vulnerability to drought by combining regional climate statistics with our data for evapotranspiration. Then we will test and validate water balances in simulations of future climate using coupled models, testing hypotheses about the role of extreme climatic events.

Final data sets will be prepared for our measurements in LBA-ECO from 1999—2005, including (a) flux, ecological and soils data in the primary forest, plus Natal concentration data and (b) the BARCA aircraft data sets. Forest data through December, 2004 have received QA/QC and been submitted to LBA-DIS. This proposal will support QA/QC and submission of data collected through November, 2005, including BARCA. Then all data will be rigorously assessed to ensure uniform calibration, and we will provide value-added products (e.g. with missing observations filled using nearby LBA sensors) designed to facilitate use by modelers.

Finally, we plan to lead a synthesis activity for the BARCA science team. We will organize comparative QA/QC of the data, interface with ecosystem modelers, and lead a data workshop in Brazil (2006) and a science/synthesis workshop in USA (2007).

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