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Aircraft- and tower-based fluxes of carbon dioxide, latent, and sensible heatFluxes of carbon dioxide, water vapor, and sensible heat obtained over a grassland ecosystem, during the First International Satellite Land Surface Climatology Project (ISLSCP) Field Experiment (FIFE), using an aircraft- and two tower-based systems are compared for several days in 1987 and in 1989. The tower-based cospectral estimates of CO2, sensible heat, water vapor, and momentum, expressed as a function of wavenumber K times sampling height z, are relatively similar to the aircraft-based estimates for K x z greater than 0.1. A measurable contribution to the fluxes is observed by tower-based systems at K x z less than 0.01 but not by the aircraft-based system operating at an altitude of approximately 100 m over a 15 x 15 km area. Using all available simultaneous aircraft and tower data, flux estimates by both systems were shown to be highly correlated. As expected from the spatial variations of the greenness index, surface extrapolation of airborne flux estimates tended to lie between those of the two tower sites. The average fluxes obtained, on July 11, 1987, and August 4, 1989, by flying a grid pattern over the FIFE site agreed with the two tower data sets for CO2, but sensible and latent heat were smaller than those obtained by the tower-based systems. However, in general, except for a small underestimation due to the long wavelength contributions and due to flux divergence with height, the differences between the aircraft- and tower-based surface estimates of fluxes appear to be mainly attributable to differences in footprint, that is, differences in the area contributing to the surface flux estimates.
Document ID
19930036590
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Desjardins, R. L.
(Agriculture Canada Centre for Land and Biological Resources Research, Ottawa, United States)
Hart, R. L.
(Argonne National Lab. IL, United States)
Macpherson, J. I.
(National Research Council of Canada, Flight Research Lab. Ottawa, United States)
Schuepp, P. H.
(McGill Univ. Sainte-Anne-de-Bellevue, Canada)
Verma, S. B.
(Nebraska Univ. Lincoln, United States)
Date Acquired
August 15, 2013
Publication Date
November 30, 1992
Publication Information
Publication: Journal of Geophysical Research
Volume: 97
Issue: D17
ISSN: 0148-0227
Subject Category
Meteorology And Climatology
Accession Number
93A20587
Funding Number(s)
CONTRACT_GRANT: NASA ORDER S-56303-D
Distribution Limits
Public
Copyright
Other

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