Spectral Emissivity (SE) Measurement Uncertainties across 2.5–14 μm Derived from a Round-Robin Study Made Across International Laboratories

Autor: Michael Koehl, Elsa A. Abbott, Martin J. Wooster, Laurent Poutier, Mary F. Langsdale, William R. Johnson, Franz Brucker, Christoph Hecker, Alessandro Maturilli, Ian C. Lau, Simon J. Hook, Jeremy J. Harrison
Přispěvatelé: Publica, Department of Earth Systems Analysis, UT-I-ITC-4DEarth, Faculty of Geo-Information Science and Earth Observation
Jazyk: angličtina
Rok vydání: 2020
Předmět:
Zdroj: Remote Sensing
Volume 13
Issue 1
Remote Sensing, Vol 13, Iss 102, p 102 (2021)
Langsdale, M, Wooster, M, Harrison, J, Koehl, M, Hecker, C, Hook, S, Abbott, E, Johnson, W, Maturilli, A, Poutier, L, Lau, I & Brucker, F 2021, ' Spectral emissivity (SE) measurement uncertainties across 2.5 – 14 μm derived from a round-robin study made across international laboratories ', REMOTE SENSING, vol. 13, no. 1, 102, pp. 1-37 . https://doi.org/10.3390/rs13010102
Remote sensing, 13(1):102, 1-37. Multidisciplinary Digital Publishing Institute (MDPI)
ISSN: 2072-4292
DOI: 10.3390/rs13010102
Popis: Information on spectral emissivity (SE) is vital when retrieving and evaluating land surface temperature (LST) estimates from remotely sensed observations. SE measurements often come from spectral libraries based upon laboratory spectroscopic measurements, with uncertainties typically derived from repeated measurements. To go further, we organised a &ldquo
round-robin&rdquo
inter-comparison exercise involving SE measurements of three samples collected at seven different international laboratories. The samples were distilled water, which has a uniformly high spectral emissivity, and two artificial samples (aluminium and gold sheets laminated in polyethylene), with variable emissivities and largely specular and Lambertian characteristics. Large differences were observed between some measurements, with standard deviations over 2.5&ndash
14 &mu
m of 0.092, 0.054 and 0.028 emissivity units (15.98%, 7.56% and 2.92%) for the laminated aluminium sheet, laminated gold sheet and distilled water respectively. Wavelength shifts of up to 0.09 &mu
m were evident between spectra from different laboratories for the specular sample, attributed to system design interacting with the angular behaviour of emissivity. We quantified the impact of these SE differences on satellite LST estimation and found that emissivity differences resulted in LSTs differing by at least 3.5 K for each artificial sample and by more than 2.5 K for the distilled water. Our findings suggest that variations between SE measurements derived via laboratory setups may be larger than previously assumed and provide a greater contribution to LST uncertainty than thought. The study highlights the need for the infrared spectroscopy community to work towards standardized and interlaboratory comparable results.
Databáze: OpenAIRE
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