Comparison of emissivity retrieval methods from ASTER data using Fourier-Transform Infrared Spectroscopy
- PDF / 3,185,226 Bytes
- 10 Pages / 595.276 x 790.866 pts Page_size
- 43 Downloads / 210 Views
RESEARCH ARTICLE - ATMOSPHERIC & SPACE SCIENCES
Comparison of emissivity retrieval methods from ASTER data using Fourier‑Transform Infrared Spectroscopy Silvia Beatriz Alves Rolim1 · Bijeesh Kozhikkodan Veettil2,3 · Pâmela Suélen Käfer1 · Atilio Efrain Bica Grondona1 · María Luján Iglesias1 · Lucas Ribeiro Diaz1 · Cristiano Lima Hackmann1 Received: 11 May 2020 / Accepted: 5 October 2020 © Institute of Geophysics, Polish Academy of Sciences & Polish Academy of Sciences 2020
Abstract Land surface emissivity retrieval is important for the remote identification of natural materials and can be used to identify the presence of silicate minerals. However, its estimation from passive sensors involves an undetermined function related to radiance data, which is influenced by the atmosphere. We tested three methods for temperature emissivity retrieval in a dune field composed of 99.53% quartz (SiO2) using Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) imagery. The tested methods were the reference channel method (RCM), emissivity normalization method (ENM), and temperature emissivity separation (TES) method. An average quartz reference spectrum for the dune samples was calculated from an emissivity database based on temperature and used to evaluate the emissivity products of four ASTER images. In general, the three tested methods had a good approximation when analysed the emissivity reference curve, especially for longer wavelengths that ranged between 2 and 4% of emissivity. The RCM and ENM produced very similar results with the coefficients of determination (R2) as 0.9960 (RMSE 0.0184) and 0.9959 (RMSE 0.0185), respectively. RCM method presented superior results (R2: 0.9960, RMSE: 0.0184), compared to the TES method (R2: 0.9947, RMSE: 0.0197). The TES method showed good results only for shorter wavelengths and, hence, to identify specific targets using ASTER data, such as silicate minerals, it is better to use the RCM method. The emissivity value selected at the saturation point of the spectral library based on temperature is fundamental in acquiring more reliable data. Keywords Land surface emissivity · ASTER data · Thermal infrared · Quartz
Introduction Land surface emissivity (LSE) is an important physical property in geological mapping, particularly in the exploration of ore deposits associated with silicates in mafic and ultramafic rocks (Christensen et al. 2000). These minerals do not always present expressive diagnostic features in their * Bijeesh Kozhikkodan Veettil [email protected] 1
Geologic Remote Sensing Laboratory (LabSRGeo), Centro Estadual de Pesquisas em Sensoriamento Remoto e Meteorologia, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Rio Grande Do Sul, Brazil
2
Department for Management of Science and Technology Development, Ton Duc Thang University, Ho Chi Minh City, Vietnam
3
Faculty of Environment and Labour Safety, Ton Duc Thang University, Ho Chi Minh City, Vietnam
spectral characteristics in the visible and shortwave infrared r
Data Loading...
