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United States Department of Agriculture

Agricultural Research Service

Title: Comparison of Aircraft-and Tower-Measured Fluxes Acquired During Smacex with Predictions from a Regional Atmosphere-Land Exchange Model

Authors
item Anderson, Martha - UNIVERSITY OF WISCONSIN
item Norman, John - UNIVERSITY OF WISCONSIN
item Kustas, William
item Prueger, John
item Neale, Chris - UTAH STATE UNIVERSITY
item Macpherson, Ian - NATL RES COUNCIL OF CANAD
item Mecikalski, John - UNIVERSITY OF WISCONSIN
item Diak, George - UNIVERSITY OF WISCONSIN

Submitted to: American Meteorological Society
Publication Type: Proceedings
Publication Acceptance Date: November 5, 2002
Publication Date: February 15, 2003
Citation: Anderson, M., Norman, J., Kustas, W.P., Prueger, J.H., Neale, C., Macpherson, I., Mecikalski, J., Diak, G. 2003. Comparison of aircraft-and tower-measured fluxes acquired during Smacex with predictions from a regional atmosphere-land exchange model. In: Proceedings of the Hydrology Conference. American Meteorological Society Annual Meeting , February 9-13, 2003.

Interpretive Summary: The Soil Moisture - Atmosphere Coupling Experiment (SMACEX) was conducted 15 June -13 July 2002 in the Walnut Creek Watershed near Ames, Iowa - an agricultural region dominated by corn and soybean production. A primary goal in SMACEX was to study the role of heterogeneity in soil moisture and vegetation cover in influencing land-atmosphere exchanges of energy, water and carbon over a range in spatial scales. During the experiment, fluxes were measured continuously at 14 towers distributed across the watershed, and periodically along tracks over flown by the NRC Twin Otter atmospheric research aircraft. Together, tower and aircraft observations sampled flux footprints on the order of 100 to 1000 m. Surface vegetation and temperature observations were collected in situ: at the 1 m pixel resolution with the Utah State University Piper Seneca remote sensing aircraft, and at 30 to 5000 m pixel resolutions with the Landsat, MODIS, AVHRR and GOES satellites. This multi-scale dataset, representing a mixture of point, linear, and gridded coverages, will be synthesized, aggregated and used to evaluate spatial scaling techniques and assumptions inherent in turbulent transport modeling. This study focused on comparing flux measurements aggregated to the watershed scale with predictions from the regional-scale Atmosphere-Land Exchange Inverse (ALEXI) model - a coupled land-surface-atmospheric boundary layer model based on satellite estimates of vegetation cover and surface radiometric temperature change.

Technical Abstract: The Soil Moisture - Atmosphere Coupling Experiment (SMACEX) was conducted 15 June -13 July 2002 in the Walnut Creek Watershed near Ames, Iowa - an agricultural region dominated by corn and soybean production. A primary goal in SMACEX was to study the role of heterogeneity in soil moisture and vegetation cover in influencing land-atmosphere exchanges of energy, water and carbon over a range in spatial scales. During the experiment, fluxes were measured continuously at 14 towers distributed across the watershed, and periodically along tracks over flown by the NRC Twin Otter atmospheric research aircraft. Together, tower and aircraft observations sampled flux footprints on the order of 100 to 1000 m. Surface vegetation and temperature observations were collected in situ: at the 1 m pixel resolution with the Utah State University Piper Seneca remote sensing aircraft (Neale et al., 2003), and at 30 to 5000 m pixel resolutions with the Landsat, MODIS, AVHRR and GOES satellites. This multi-scale dataset, representing a mixture of point, linear, and gridded coverages, will be synthesized, aggregated and used to evaluate spatial scaling techniques and assumptions inherent in turbulent transport modeling. This paper will compare flux measurements aggregated to the watershed scale with predictions from the regional-scale Atmosphere-Land Exchange Inverse (ALEXI) model - a coupled land-surface-atmospheric boundary layer model based on satellite estimates of vegetation cover and surface radiometric temperature change.

Last Modified: 12/26/2014
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