Using precipitation, vertical root distribution, and satellite-retrieved vegetation information to parameterize water stress in a Penman-Monteith approach to evapotranspiration modeling under Mediterranean climate [electronic resource].
- Washington, D.C. : United States. Dept. of Energy. Office of Science, 2017. and Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy
- Physical Description:
- pages 168-192 : digital, PDF file
- Additional Creators:
- United States. Department of Energy. Office of Science and United States. Department of Energy. Office of Scientific and Technical Information
- Restrictions on Access:
- Free-to-read Unrestricted online access
- Here, recent studies have shown that global Penman-Monteith equation based (PM-based) models poorly simulate water stress when estimating evapotranspiration (ET) in areas having a Mediterranean climate (AMC). In this study, we propose a novel approach using precipitation, vertical root distribution (VRD), and satellite-retrieved vegetation information to simulate water stress in a PM-based model (RS-WBPM) to address this issue. A multilayer water balance module is employed to simulate the soil water stress factor (SWSF) of multiple soil layers at different depths. The water stress factor (WSF) for surface evapotranspiration is determined by VRD information and SWSF in each layer. Additionally, four older PM-based models (PMOV) are evaluated at 27 flux sites in AMC. Results show that PMOV fails to estimate the magnitude or capture the variation of ET in summer at most sites, whereas RS-WBPM is successful. The daily ET resulting from RS-WBPM incorporating recommended VI (NDVI for shrub and EVI for other biomes) agrees well with observations, with <sub>R<sup>2</sup> = 0.60</sub> (<sub>RMSE</sub> = 18.72 <sub>W m<sup>-2</sup></sub>) for all 27 sites and <sub>R<sup>2</sup>=0.62</sub> (<sub>RMSE</sub> 5 18.21 <sub>W m<sup>-2</sup></sub>) for 25 nonagricultural sites. However, combined results from the optimum older PM-based models at specific sites show <sub>R<sup>2</sup> values of only 0.50</sub> (<sub>RMSE</sub> 5 20.74 <sub>W m<sup>-2</sup></sub>) for all 27 sites. RS-WBPM is also found to outperform other ET models that also incorporate a soil water balance module. As all inputs of RS-WBPM are globally available, the results from RS-WBPM are encouraging and imply the potential of its implementation on a regional and global scale.
- Published through SciTech Connect., 01/04/2017., Journal of Advances in Modeling Earth Systems 9 1 ISSN 1942-2466 AM, Yun Bai; Jiahua Zhang; Sha Zhang; Upama Ashish Koju; Fengmei Yao; Tertsea Igbawua., and Oregon State Univ., Corvallis, OR (United States)
- Funding Information:
- FG02-04ER63917 and FG02-04ER63911
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