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Validating Airborne Multispectral Remotely Sensed Heat Fluxes with Ground Energy Balance Tower and Heat Flux Source Area (Footprint) Functions

Published by the American Society of Agricultural and Biological Engineers, St. Joseph, Michigan www.asabe.org

Citation:  Paper number  033128,  2003 ASAE Annual Meeting . (doi: 10.13031/2013.15014) @2003
Authors:   Jose L. Chavez, Christopher M. U. Neale
Keywords:   Airborne remote sensing, evapotranspiration, energy balance, heat flux source area, footprint analysis

In an effort to validate airborne remote sensing latent heat flux estimates (evapotranspiration rate), different procedures to improve the determination of net radiation, soil heat flux, and sensible heat flux were tested. Latent heat flux was determined as a residual from the energy balance equation. The resulting heat flux images were integrated using 1D and 2D heat flux source area models (footprint models) and were compared to Eddy covariance energy balance ground measurements (3D Sonic Anemometer). The results showed that the aerodynamic temperature is related to surface radiometric temperature and leaf area index. In addition, different soil heat flux, LAI, sensible heat flux, and footprint models were used to find the more appropriate models for the remote sensing procedure. The results are encouraging, showing rmse values for LE 44% lower than other studies and uncertainties of the same order of those expected for the Eddy covariance system and for the Remote sensing procedure, when Ahmed (1997) soil heat flux model, Chehbouni et al. (1997a) sensible heat flux model, and Gash (1986) footprint model were used.

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