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United States Department of Agriculture

Agricultural Research Service

Title: Simulating Evapotranspiration from Rangelands: Simple Vs. Complex Models

Authors
item Wight, J
item Flerchinger, Gerald
item Hanson, Clayton

Submitted to: International Rangeland Congress
Publication Type: Proceedings
Publication Acceptance Date: July 1, 1995
Publication Date: N/A

Interpretive Summary: Evapotranspiration (ET) models and submodels vary over a wide range of complexity in terms of data requirements, ease of operation, and accuracy. To effectively match an ET model with a specific application, it is necessary to have the appropriate information concerning the candidate models. We evaluated the ET components of a simple climate, water-balance model (ERHYM) and a complex, process-oriented ET model (SHAW) on a sagebrush-grass watershed. A Bowen ratio-energy balance system was used to measure ET from the watershed. Both models simulated daily and seasonal ET with reasonable accuracy. Advantages of the complex ET model included its ability to simulate hourly ET fluxes, individual plant species, and ET over a wide range of conditions without prior calibration. Disadvantages of the complex model were the large amount of input information for rangeland sites, and complexity of operation. This information will improve the development and application of natural resource models by enhancing the match of interactive model components in terms of resolution, accuracy, model inputs, and available data.

Technical Abstract: We compared a simple and a complex, process-oriented ET model in terms of data requirements, ease of operation, and accuracy. Both models simulated daily and seasonal ET with reasonable accuracy. Advantages of the complex ET model included its ability to simulate hourly ET fluxes, individual plant species, and ET over a wide range of conditions without prior calibration. Disadvantages of the complex model were the large amount of input information required, the limited availability of such information for rangeland sites, and complexity of operation.

Last Modified: 8/27/2014
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