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Proceedings of the International Association of Hydrological Sciences An open-access publication for refereed proceedings in hydrology
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Volume 368
Proc. IAHS, 368, 379–384, 2015
https://doi.org/10.5194/piahs-368-379-2015
© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.
Proc. IAHS, 368, 379–384, 2015
https://doi.org/10.5194/piahs-368-379-2015
© Author(s) 2015. This work is distributed under
the Creative Commons Attribution 3.0 License.

  07 May 2015

07 May 2015

Combining the trapezoidal relationship between land surface temperature and vegetation index with the Priestley-Taylor equation to estimate evapotranspiration

X. Wang, W. Wang, and Y. Jiang X. Wang et al.
  • State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing 210098, China

Keywords: Actual evapotranspiration, land surface temperature−vegetation index trapezoid, Priestley-Taylor equation, remote sensing

Abstract. Evapotranspiration (ET) plays an important role in the hydrological cycle. A method of combining the Priestley-Taylor (P-T) equation with a trapezoidal space between land surface temperature (Ts) and enhanced vegetation index (EVI) is proposed based on the principle of energy balance. Generally, this method is divided into three major parts: (1) construct the Ts versus EVI (Ts-VI) trapezoidal space for calculating the Ts at four extreme conditions (i.e. well-watered vegetation, water-stressed vegetation, saturated bare soil and dry bare soil); (2) calculate the P-T coefficient for each pixel according to the position of the observed (EVI, Ts) point in the trapezoid space; (3) calculate actual ET of the pixel using the P-T equation. The method is validated using Landsat-8 images and ground-observed data for a semi-humid area in China. The result shows that the ET estimates match the observations well, which indicates the effectiveness the proposed method here.

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