Validation of a temperature emissivity separation hybrid method from airborne hyperspectral scanner data and ground measurements in the SEN2FLEX field campaign
Abstract:This paper presents an assessment of the performance of a hybrid method that allows a simultaneous retrieval of land-surface temperature (LST) and emissivity (LSE) from remotely-sensed data. The proposed method is based on a synergistic usage of the split-window (SW) algorithm and the two-temperature method (TTM) and combines the advantages of both procedures while mitigating their drawbacks. The method was implemented for thermal channels 76 (10.56 µm) and 78 (11.72 µm) of the Airborne Hyperspectral Scanner (AHS), which was flown over the Barrax test site (Albacete, Spain) in the second week of July 2005, within the framework of the Sentinel-2 and Fluorescence Experiment (SEN2FLEX) field campaign. A set of radiometric measurements was performed in the thermal infrared region in coincidence with aircraft overpasses for different surface types, e.g. bare soil, water body, corn, wheat, grass. The hybrid method was tested and compared with a standard SW algorithm and the results obtained show that the hybrid method is able to provide better estimates of LST, with values of bias (RMSE) of the order of 0.8 K (1.9 K), i.e. about one third (one half) of the corresponding values of 2.7 K (3.4 K) that were obtained for bias (RMSE) when using the SW algorithm. These figures provide a sound indication that the developed hybrid method is particularly useful for surface and atmospheric conditions where SW algorithms cannot be accurately applied.
Document Type: Research Article
Affiliations: 1: Instituto Nacional de Pesquisas Espaciais - Centro de Previsao de Tempo e Estudos Climaticos - Rod. Pres Dutra, Cachoeira Paulista/SP, Brazil,University of Lisbon, CGUL, IDL, Campo Grande, 1749-016, Lisbon, Portugal 2: Global Change Unit, Department of Thermodynamics, Faculty of Physics, University of Valencia, 46100, Burjassot, Spain 3: University of Lisbon, CGUL, IDL, Campo Grande, 1749-016, Lisbon, Portugal
Publication date: December 1, 2008