CD-03 Abstract

Periodic, transient, and spatially inhomogeneous influences on C exchange in Amaznia

David R. Fitzjarrald, State University of New York, Albany (US-PI)
Osvaldo Luiz Leal de Moraes, Universidade Federal de Santa Maria (UFSM) (SA-PI)

We propose observations and analyses to infer transports of CO2, water vapor, and energy from the natural and the disturbed regions of Amazonia.  We ask support to continue ongoing direct surface climate and flux measurements at several sites in LBA-ECO.  Fluxes will also be estimated using the boundary layer budget approach.  A major focus will be to determine how carbon fluxes are influenced by natural and human-induced landscape inhomogeneities.  Scales of inhomogeneities addressed range from the river-land contrast, the pasture-forest contrast, and the gap-closed canopy contrast inside the forest.  Special attention will go to understanding how changes in agricultural practices in the Amazon alter carbon exchanges in cleared areas.  One new initiative aims to improve understanding of the respiration rate in forests by studying subcanopy flows.  A second new initiative to quantify canopy structure to relate this structure to the forest flux tower observations is proposed.  This proposal addresses LBA-ECO Science Questions CDQ1 CDQ3b, and LCQ1.

Our objectives are:

1) To observe local wind circulations (river and land breezes, drainage flows) and assess their influence on boundary layer development.  To infer surface heat, water vapor, and CO2 fluxes from  temporal changes in their canopy and boundary layer concentrations .

2) To relate light availability to the ecosystem to cloudiness, and to determine the resulting effect on  net ecosystem carbon exchange (NEE).

3) To quantify how land use change from pasture to cultivation alters the carbon budget in one cleared area, and develop parameterizations of exchange processes  for modeling.

4) To quantify the vertical and horizontal structure of the forest canopy near flux towers in the Tapajos National Forest.

5) To relate canopy structure n to turbulent canopy-atmosphere exchange in regions of closed-canopy primary forest, near natural gaps, and in the cut-over mosaic of a selectively logged site.

6)  To reduce uncertainties in long-term tower flux observations of the respiration rate )through better understanding the effect of subcanopy drainage flows at two LBA-ECO Study Areas.