HR: 10:50h
AN: B52B-03    [Abstracts]
TI: Improving Regional Estimates of Carbon Exchange through a New Method of Analyzing Aircraft Flux Data
AU: * Williamson, D
EM: dwilliamson@eng.ua.edu
AF: The University of ALabama The University of Alabama, Civil Engineering-AERO Box 870205, Tuscaloosa, AL 35473,
AU: Kirby, S
EM: sak4ua@yahoo.com
AF: The University of ALabama The University of Alabama, Civil Engineering-AERO Box 870205, Tuscaloosa, AL 35473,
AU: Dobosy, R
EM: ron.dobosy@noaa.gov
AF: NOAA-Air Resources Lab, ATDD 456 South Illinois Avenue, oak Ridge, TN 37831,
AB: Regional carbon flux measurements are routinely performed using top down or bottom-up methodologies. Merging, comparing, or cross-validating these methods may require more data and further description of variance in reported data. While some surfaces are homogeneous at both local and regional scales, local scale ( ~ 1 km) heterogeneous or patchwork landscapes are becoming ever more common. Individual flux towers may accurately reflect the flux from a single patch, or a unique assemblage of several patches. However, the ability of a single tower (or even several) to quantitatively represent the distribution of fluxes from a variety of land covers and management practices is limited. Flux aircraft have often been used to represent regional fluxes. Local- scale heterogeneities may limit the usefulness of aircraft data for regional scaling. Traditional flux calculations use 3-5km averaging lengths that are often too large to capture such heterogeneities. The flux fragment method is a newly developed method for aggregating fluxes within an aircraft transect not by contiguous length (that often convolutes separate surface covers) but by highly resolved land classification. The result of this method provides a land use specific flux over a studied region (~10-100km). This can then be scaled by land use and compared to top-down regional (~1000km) estimates. Moreover, the flux fragment method provides an estimate of the spatial variance of fluxes per land use. This variance can then be used to place the results of a single flux tower within a larger context. Such variance descriptions are imperative when comparing top-down and bottom-up approaches to determine if differences between methods are significant or fall within the range of expected uncertainty from each approach. This flux fragment method was developed and the utility verified within the maize and soybean ecosystem of mid-continental North America.
DE: 0452 Instruments and techniques
DE: 4806 Carbon cycling (0428)
SC: Biogeosciences [B]
MN: 2007 Fall Meeting