Submitted to: Environmental and Water Resources Institute World Congress Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 5/1/2009
Publication Date: 5/17/2009
Citation: Kjaersgaard, J., Gowda, P., Allen, R., Howell, T.A. 2009. Independent comparisons among calibration and output of energy balance components estimated by the METRIC procedure. Environmental and Water Resources Institute World Congress Proceedings. May 17-21, 2009, Kansas City, Missouri, p.4362-4371. 2009 CDROM Interpretive Summary: Considerable uncertainty exists regarding the spatial and temporal variability of the consumptive water use. The variability is caused by local and regional differences in weather, precipitation, soil, land use, vegetation type, cultivar and cropping system, irrigation application method, and land management. In this study, two independent groups developed evapotranspiration maps from a high resolution satellite image using a energy balance model. Results were compared for discrepancies in implementing the model.
Technical Abstract: An accurate estimation of evapotranspiration (ET) is an integral part of the hydrological cycle and is important in local and regional water resource management in central and western United States. Traditionally, estimation of ET included substantial uncertainties, but with the advent of algorithms applied to high spatial resolution (30 m) satellite imagery, ET estimates from bare soil and vegetation can be obtained with greater accuracy. The METRIC image processing model estimates net radiation, soil heat flux, and sensible heat flux through a series of steps before estimating ET as the residual from the energy balance. This paper describes a comparison of the METRIC surface energy balance model outputs produced by two different research groups when using the same 2007 Landsat 5 image as input. One of the research groups is based at the USDA-ARS Conservation and Production Research Laboratory in Bushland, Texas, where the images and ground-based data were captured; and the other group is from the Kimberly Research Center, University of Idaho, where METRIC was developed.