Bridging thermal infrared sensing and physically-based evapotranspiration modeling: from theoretical implementation to validation across an aridity gradient in Australian ecosystems

Mallick, Kaniska, Toivonen, Erika, Trebs, Ivonne, Boegh, Eva, Cleverly, James, Eamus, Derek, Koivusalo, Harri, Drewry, Darren, Arndt, Stefan K., Griebel, Anne, Beringer, Jason, and Garcia, Monica (2018) Bridging thermal infrared sensing and physically-based evapotranspiration modeling: from theoretical implementation to validation across an aridity gradient in Australian ecosystems. Water Resources Research, 54 (5). pp. 3409-3435.

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Abstract

Thermal infrared sensing of evapotranspiration (E) through surface energy balance (SEB) models is challenging due to uncertainties in determining the aerodynamic conductance (gA) and due to inequalities between radiometric (TR) and aerodynamic temperatures (T0). We evaluated a novel analytical model, the Surface Temperature Initiated Closure (STIC1.2), that physically integrates TR observations into a combined Penman-Monteith Shuttleworth-Wallace (PM-SW) framework for directly estimating E, and overcoming the uncertainties associated with T0 and gA determination. An evaluation of STIC1.2 against high temporal frequency SEB flux measurements across an aridity gradient in Australia revealed a systematic error of 10–52% in E from mesic to arid ecosystem, and low systematic error in sensible heat fluxes (H) (12–25%) in all ecosystems. Uncertainty in TR versus moisture availability relationship, stationarity assumption in surface emissivity, and SEB closure corrections in E were predominantly responsible for systematic E errors in arid and semi-arid ecosystems. A discrete correlation (r) of the model errors with observed soil moisture variance (r = 0.33–0.43), evaporative index (r = 0.77–0.90), and climatological dryness (r = 0.60–0.77) explained a strong association between ecohydrological extremes and TR in determining the error structure of STIC1.2 predicted fluxes. Being independent of any leaf-scale biophysical parameterization, the model might be an important value addition in working group (WG2) of the Australian Energy and Water Exchange (OzEWEX) research initiative which focuses on observations to evaluate and compare biophysical models of energy and water cycle components.

Item ID: 73474
Item Type: Article (Research - C1)
ISSN: 1944-7973
Keywords: evapotranspiration, thermal infrared sensing, land surface temperature, surface energy balance, Penman-Monteith, Shuttleworth-Wallace, aridity gradient, Australia
Copyright Information: © 2018. The Authors. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.
Funders: Australian Research Council (ARC)
Projects and Grants: ARC DP0344744, ARC DP0772981, ARC DP120101735, ARC DP130101566, ARC LE0882936, ARC FT110100602
Date Deposited: 24 May 2022 05:51
FoR Codes: 37 EARTH SCIENCES > 3707 Hydrology > 370702 Ecohydrology @ 50%
41 ENVIRONMENTAL SCIENCES > 4102 Ecological applications > 410203 Ecosystem function @ 50%
SEO Codes: 18 ENVIRONMENTAL MANAGEMENT > 1806 Terrestrial systems and management > 180601 Assessment and management of terrestrial ecosystems @ 100%
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