A New Contextual Parameterization of Evaporative Fraction to Reduce the Reliance of the Ts − VI Triangle Method on the Dry Edge
Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China
Author to whom correspondence should be addressed.
Academic Editors: Soe Myint, Richard Müller and Prasad S. Thenkabail
Received: 29 September 2016 / Revised: 13 December 2016 / Accepted: 17 December 2016 / Published: 4 January 2017
In this study, a new parameterization scheme of evaporative fraction (EF) was developed from the contextual information of remotely sensed radiative surface temperature (
) and vegetation index (VI). In the traditional
triangle methods, the Priestley-Taylor parameter
of each pixel was interpolated for each VI interval; in our proposed new parameterization scheme (NPS), it was performed for each isopiestic line of soil surface moisture. Specifically,
of mixed pixels was determined as the weighted-average value of bare soil
and full-cover vegetation
. The maximum
of bare soil (
) is the sole parameter needed as the constraint of the dry edge. This has not only bypassed the task involved in the determination of the maximum
of fully vegetated surface (
), but also made it possible to reduce the reliance of the
triangle methods on the determination of the dry edge. Ground-based measurements taken during 21 days in 2004 were used to validate the EF retrievals. Results show that the accuracy achieved by the NPS is comparable to that achieved by the traditional
triangle methods. Therefore, the simplicity of the proposed new parameterization scheme does not compromise its accuracy in monitoring EF.
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MDPI and ACS Style
Zhu, W.; Lv, A.; Jia, S.; Yan, J. A New Contextual Parameterization of Evaporative Fraction to Reduce the Reliance of the Ts − VI Triangle Method on the Dry Edge. Remote Sens. 2017, 9, 26.
Zhu W, Lv A, Jia S, Yan J. A New Contextual Parameterization of Evaporative Fraction to Reduce the Reliance of the Ts − VI Triangle Method on the Dry Edge. Remote Sensing. 2017; 9(1):26.
Zhu, Wenbin; Lv, Aifeng; Jia, Shaofeng; Yan, Jiabao. 2017. "A New Contextual Parameterization of Evaporative Fraction to Reduce the Reliance of the Ts − VI Triangle Method on the Dry Edge." Remote Sens. 9, no. 1: 26.
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