Location: Hydrology and Remote Sensing LaboratoryTitle: Explaining the aerodynamic versus radiometric surface temperature paradox in thermal-based evaporation modeling
|MALLICK, K. - Centre De Recherche Public - Gabriel Lippmann
|JARVIS, A. - Lancaster University
|BALDOCCHI, D. - University Of California
|HU, T. - Centre De Recherche Public - Gabriel Lippmann
|TREBS, I. - Centre De Recherche Public - Gabriel Lippmann
|SULIS, M. - Centre De Recherche Public - Gabriel Lippmann
|BOSSUNG, C. - Centre De Recherche Public - Gabriel Lippmann
|EID, Y. - University Of Wurzburg
|CLEVERLY, J. - University Of Adelaide
|BERINGER, J. - University Of Western Australia
|WOODGATE, W. - University Of Western Australia
|SLBERSTEIN, R. - Edith Cowan University (ECU)
Submitted to: Geophysical Research Letters
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/6/2022
Publication Date: 8/9/2022
Citation: Mallick, K., Jarvis, A., Baldocchi, D., Hu, T., Trebs, I., Sulis, M., Bossung, C., Bhattarai, N., Eid, Y., Cleverly, J., Beringer, J., Woodgate, W., Slberstein, R. 2022. Explaining the aerodynamic versus radiometric surface temperature paradox in thermal-based evaporation modeling. Geophysical Research Letters. 49:e2021GL097568. https://doi.org/10.1029/2021GL097568.
Interpretive Summary: Aerodynamic temperature drives the sensible heat flux between land surface and atmosphere, and consequently affects the evapotranspiration (ET). Yet, this temperature is an unobserved component in the surface energy balance models. A new physically-based analytical model of the surface energy balance where ET and sensible heat fluxes are directly estimated is applied to a range of contrasting arid ecosystems in Australia. Overall, the results of this study demonstrate that the components of surface energy balance can be estimated from physical principles, which represents an alternative and novel perspective to ET estimation in highly complex landscapes using remotely sensed land surface temperature.
Technical Abstract: One of the longstanding research questions in thermal remote sensing of evaporation is to resolve the incongruity between aerodynamic and radiometric surface temperature. Resolving their difference would help to bypass some of the empirical conductance parameterizations in global models. To explain their inequality, this work proposes a physically-based analytical framework of the surface energy balance where evaporation and sensible heat fluxes are directly estimated by constraining the state equations of aerodynamic temperature and biophysical conductances through radiometric temperature. While the derived aerodynamic temperature compared reasonably well with a flux-inverted counterpart, evaporation and sensible heat fluxes also showed very good correspondence when compared with in-situ observations in a range of contrasting arid ecosystems in Australia. Our results showed aerodynamic temperature frequently overruns the radiometric temperature in arid and semiarid ecosystems as a result of decline in canopy-surface conductance and evaporative fraction due to diminishing soil water content and excessive vapor pressure deficit and simultaneous increase in aerodynamic conductance, air temperature and sensible heat flux.