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www.hydrol-earth-syst-sci-discuss.net/7/461/2010/
doi:10.5194/hessd-7-461-2010
© Author(s) 2010. This work is distributed
under the Creative Commons Attribution 3.0 License.
Evaluation of Penman-Monteith model applied to a maize field in the arid area of Northwest China
1Heihe Key Laboratory of Ecohydrology and Integrated River Basin Science, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou, 730000, China
2Linze Inland River Basin Comprehensive Research Station, Chinese Ecosystem Research Network, Lanzhou, 730000, China
Abstract. The Penman-Monteith (P-M) model has been applied to estimate evapotranspiration in terrestrial ecosystem widely in the world. As shown in many studies, bulk canopy resistance is an especially important factor in the application of P-M model. In this study, the authors used the Noilhan and Planton (N-P) approach and Jacobs and De Bruin (J-D) approach to express the bulk canopy resistance. The application of P-M mode to a maize field with two approaches in the arid area of Northwest China was evaluated by the measured half-hourly values from the eddy covariance system. The results indicate that the N-P approach underestimates slightly the bulk canopy resistance, while the J-D approach overestimates that. The estimation of bulk canopy resistance with N-P approach was then better and more consistent than that with J-D approach during the entire maize growing season. Correspondingly, the P-M model with J-D bulk canopy resistance slightly underestimated the latent heat flux throughout the maize growing season, but overestimated the latent heat flux during the dry period of the soil as compared to that with N-P approach. The good fitness of the simulated latent heat flux by the P-M model with N-P bulk canopy resistance approach to the measured one at a half-hour time step demonstrates the application of the approach is reasonable in the relative homogenous and not drought-stressed maize fields of the arid areas during the entire growing season. Further researches are discussed on enhancing the field observation, taking the correction for atmospheric stability into estimating aerodynamic resistance, to improve the performance of P-M model to simulate evapotranspiration in the cropped fields.
Discussion Paper (PDF, 1034 KB) Interactive Discussion (Closed, 11 Comments) Final Revised Paper (HESS)
Citation: Zhao, W.-Z., Ji, X.-B., Kang, E.-S., Zhang, Z.-H., and Jin, B.-W.: Evaluation of Penman-Monteith model applied to a maize field in the arid area of Northwest China, Hydrol. Earth Syst. Sci. Discuss., 7, 461-491, doi:10.5194/hessd-7-461-2010, 2010. Bibtex EndNote Reference Manager XML
