Quantifying the
regional scale (10-1000 km) exchange of carbon dioxide between terrestrial
ecosystems and the atmosphere is vital for understanding the spatial and
temporal variation in global CO2 flux. Multiple investigations of
top-down and bottom-up regional flux scaling are currently underway in the
northern Great Lakes region, USA. Landscape and regional scale CO2
fluxes from multiple line of evidence, including eddy covariance multi-tower
aggregation, tall-tower flux footprint decomposition, ecosystem modeling, CO2
mixing ratio boundary layer budgets and regional inversions reveal variations
in CO2 flux arising from variations in vegetation type, canopy
structure and interannual climate variability. With careful calibration, encouraging
consistency is seen from several independent regional flux estimates. Without
parameter optimization and high resolution maps of land cover, global scale
remote-sensing and ecosystem-model CO2 flux estimates fail to
accurately capture the local regional CO2 flux. These results
represent a first attempt to cross-compare multiple top-down and bottom-up
regional flux estimates.
Author: A.R. Desai, W. Wang, D.M. Ricciuto, B.D. Cook, et al (adesai at psu dot edu)
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