2026-04-18T04:26:37Zhttps://recercat.cat/oai/requestoai:recercat.cat:20.500.12327/23382025-10-22T11:07:11Zcom_2072_4428com_2072_4427col_2072_487898
RECERCAT
author
Mwangi, S.
author
Boulet, G.
author
LePage, M.
author
Gastellu-Etchegorry, J-P.
author
Bellvert, Joaquim
author
Lemaire, B.
author
Fanise, P.
author
Roujean, J-L.
author
Olioso, A.
other
Producció Vegetal
group
Ús Eficient de l'Aigua en Agricultura
2025-10-22T11:07:11Z
2025-10-22T11:07:11Z
2023-07-21
Mwangi S, G. Boulet, M. LePage, J-P. Gastellu-Etchegorry, J. Bellvert, B. Lemaire, and P. Fanise et al. 2023. "Observation And Assessment Of Model Retrievals Of Surface Exchange Components Over A Row Canopy Using Directional Thermal Data". IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. doi: 10.1109/JSTARS.2023.3297709.
1939-1404
http://hdl.handle.net/20.500.12327/2338
https://doi.org/10.1109/JSTARS.2023.3297709
Land surface temperature is an essential climate variable that can serve as a proxy for detecting water deficiencies in croplands and wooded areas. Its measurement can however be influenced by anisotropic properties of surface targets leading to occurrence of directional effects on the signal. This may lead to an incorrect interpretation of thermal measurements. In this study, we perform model assessments and check the influence of thermal radiation directionality using data over a vineyard. To derive the overall directional surface temperatures, elemental values measured by individual cameras were aggregated according to the respective cover fractions/weights in viewing direction. Aggregated temperatures from the turbid model were compared to corresponding temperatures simulated by the 3D DART radiative transfer model. The reconstructed temperatures were then used in surface-energy-balance (SEB) simulations to assess the impact of the Sun-target-sensor geometry on retrievals. Here, the pseudo-isotropic Soil-Plant-Atmosphere-Remote-Sensing-of-Evapotranspiration (SPARSE) dual-source model together with the non-isotropic version (SPARSE4), were used. Both schemes were able to retrieve overall fluxes satisfactorily, confirming a previous study. However, the sensitivity (of flux and component temperature estimates) of the schemes to viewing direction was tested for the first time using reconstructed sets of directional thermal data to force the models. Degradation (relative to nadir) in flux retrieval cross-row was observed, with better consistency along rows. Overall, it was nevertheless shown that SPARSE4 is less influenced by the viewing direction of the temperature than SPARSE, particularly for strongly off-nadir viewing. Some directional/asymmetrical artefacts are however not well reproduced by the simple Radiative Transfer Methods (RTM), which can then manifest in and influence the subsequent thermal-infrared-driven SEB modelling.
eng
Observation and assessment of model retrievals of surface exchange components over a row canopy using directional thermal data
info:eu-repo/semantics/article