U.S. Department of EnergyOffice of Scientific and Technical Information
Iterative retrieval of surface emissivity and temperature for a hyperspectral sensor
Abstract
The central problem of temperature-emissivity separation is that we obtain N spectral measurements of radiance and need to find N + 1 unknowns (N emissivities and one temperature). To solve this problem in the presence of the atmosphere we need to find even more unknowns: N spectral transmissions {tau}{sub atmo}({lambda}) up-welling path radiances L{sub path}{up_arrow}({lambda}) and N down-welling path radiances L{sub path}{down_arrow}({lambda}). Fortunately there are radiative transfer codes such as MODTRAN 3 and FASCODE available to get good estimates of {tau}{sub atmo}({lambda}), L{sub path}{up_arrow}({lambda}) and L{sub path}{down_arrow}({lambda}) in the order of a few percent. With the growing use of hyperspectral imagers, e.g. AVIRIS in the visible and short-wave infrared there is hope of using such instruments in the mid-wave and thermal IR (TIR) some day. We believe that this will enable us to get around using the present temperature - emissivity separation (TES) algorithms using methods which take advantage of the many channels available in hyperspectral imagers. The first idea we had is to take advantage of the simple fact that a typical surface emissivity spectrum is rather smooth compared to spectral features introduced by the atmosphere. Thus iterative solution techniques can be devised which retrieve emissivity spectra {epsilon} basedmore »
- Authors:
- Publication Date:
- Research Org.:
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- Sponsoring Org.:
- USDOE, Washington, DC (United States)
- OSTI Identifier:
- 548853
- Report Number(s):
- LA-UR-97-3012; CONF-9705196-
ON: DE98001085; TRN: 97:005878
- DOE Contract Number:
- W-7405-ENG-36
- Resource Type:
- Conference
- Resource Relation:
- Conference: JPL workshop/remote sensing of land surface emissivity, Pasadena, CA (United States), 6-8 May 1997; Other Information: PBD: 1997
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 58 GEOSCIENCES; 66 PHYSICS; EARTH PLANET; REMOTE SENSING; TEMPERATURE MEASUREMENT; SPECTRALLY SELECTIVE SURFACES; EMISSIVITY; ITERATIVE METHODS; EMISSION SPECTRA; ALGORITHMS; RADIATION DETECTION; EARTH ATMOSPHERE
Citation Formats
Borel, C C. Iterative retrieval of surface emissivity and temperature for a hyperspectral sensor. United States: N. p., 1997.
Web.
Borel, C C. Iterative retrieval of surface emissivity and temperature for a hyperspectral sensor. United States.
Borel, C C. 1997.
"Iterative retrieval of surface emissivity and temperature for a hyperspectral sensor". United States. https://www.osti.gov/servlets/purl/548853.
@article{osti_548853,
title = {Iterative retrieval of surface emissivity and temperature for a hyperspectral sensor},
author = {Borel, C C},
abstractNote = {The central problem of temperature-emissivity separation is that we obtain N spectral measurements of radiance and need to find N + 1 unknowns (N emissivities and one temperature). To solve this problem in the presence of the atmosphere we need to find even more unknowns: N spectral transmissions {tau}{sub atmo}({lambda}) up-welling path radiances L{sub path}{up_arrow}({lambda}) and N down-welling path radiances L{sub path}{down_arrow}({lambda}). Fortunately there are radiative transfer codes such as MODTRAN 3 and FASCODE available to get good estimates of {tau}{sub atmo}({lambda}), L{sub path}{up_arrow}({lambda}) and L{sub path}{down_arrow}({lambda}) in the order of a few percent. With the growing use of hyperspectral imagers, e.g. AVIRIS in the visible and short-wave infrared there is hope of using such instruments in the mid-wave and thermal IR (TIR) some day. We believe that this will enable us to get around using the present temperature - emissivity separation (TES) algorithms using methods which take advantage of the many channels available in hyperspectral imagers. The first idea we had is to take advantage of the simple fact that a typical surface emissivity spectrum is rather smooth compared to spectral features introduced by the atmosphere. Thus iterative solution techniques can be devised which retrieve emissivity spectra {epsilon} based on spectral smoothness. To make the emissivities realistic, atmospheric parameters are varied using approximations, look-up tables derived from a radiative transfer code and spectral libraries. By varying the surface temperature over a small range a series of emissivity spectra are calculated. The one with the smoothest characteristic is chosen. The algorithm was tested on synthetic data using MODTRAN and the Salisbury emissivity database.},
doi = {},
url = {https://www.osti.gov/biblio/548853},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sat Nov 01 00:00:00 EST 1997},
month = {Sat Nov 01 00:00:00 EST 1997}
}