Thesis: Land surface temperature retrieval in urban areas from high spatial resolution thermal infrared data

Thesis defense: Xiaopo ZHENG

Title: Land surface temperature retrieval in urban areas from high spatial resolution thermal infrared data

Team: TRIO

Abstract: Land surface temperature (LST) is one of the most important Earth System Data, which could be used to characterize the Earth surface processes relating to the energy and hydrology balance. Thus, it is required in a variety of the researches including the monitoring of the urban environment, which requires the accurate urban LST as one of the most essential input parameters. However, there are still some factors influencing the LST retrieval accuracy in urban areas especially for high spatial resolution satellite TIR measurements but have not been well addressed in existing LST retrieval algorithms yet: (1) the adjacency effect in the TIR spectral region; (2) the impact of the three-dimensional (3-D) structures and their radiation on the TIR measurements; (3) the dependence of the existing LST retrieval algorithms on the accurate prior knowledge of the atmosphere and/or the Earth surface emissivity. This thesis is dedicated to developing an improved LST retrieval method for high spatial resolution satellite TIR measurements of urban areas with consideration of these three factors. Firstly, the forward adjacency effect radiative transfer model (FAERTM) has been developed to provide a useful tool for correcting the adjacency effect; Then, the analytical thermal infrared radiative transfer model over urban areas (ATIMOU) has been deduced to help to address the impact of the3-D structures and their radiation. Next, the prior-knowledge-free (PKF) LST retrieval method has been developed to get rid of the dependence on accurate atmospheric parameters and/or the Earth surface emissivity during the LST retrieval. Finally, the preliminary exploration on developing an improved LST retrieval method for high spatial resolution satellite TIR measurements of urban areas has been given. Results show that the urban LST could be retrieved with a RMSE of 3.33 K if the PKF LST retrieval method has been applied to the urban TOA measurements directly. When implementing the improved LST retrieval method, the urban LST retrieval RMSE decreases to 1.06 K, indicating the good performance of the improved LST retrieval method for high spatial resolution TIR measurements of urban areas, in which the three mentioned factors influencing the LST retrieval accuracy in urban areas have been addressed by the proposed FAERTM, ATIMOU, and PKF LST retrieval method respectively.

Keywords: LST, TIR, radiative transfer, adjacency effect, three-dimensional

The jury is composed by M. Zhao-Liang LI (Directeur de Recherche) - Thesis Director, M. J. Sobrino (PR PUPH) - Rapporteur, M. X. Briottet (Directeur de recherche) - Rapporteur, Mme F. Nerry (Directeur de recherche), M. H. Wu (Directeur de Recherche), Mme J. Labed (MCF-MCUPH) and M. B-H. Tang (Directeur de Recherche).

The defense will be held in English, on October 10th at 3p.m. in the Room B248, Pôle API on the Illkirch campus.