By Andrew R. Korb, Peter Dybwad, Winthrop Wadsworth, and John W. Salisbury
ABSTRACT
A hand-held, battery-powered Fourier transform infrared spectroradiometer weighing 12.5 kg has been developed for the field measurement of spectral radiance from the Earth’s surface and atmosphere in the 3–5-µm and 8–14-µm atmospheric windows, with a 6-cm21 spectral resolution. Other versions of this instrument measure spectral radiance between 0.4 and 20 µm, using different optical materials and detectors, with maximum spectral resolutions of 1 cm21. The instrument tested here has a measured noise-equivalent delta T of 0.01 °C, and it measures surface emissivities, in the ?eld, with an accuracy of 0.02 or better in the 8–14-µm window 1depending on atmospheric conditions2, and within 0.04 in accessible regions of the 3–5-µm window. The unique, patented design of the interferometer has permitted operation in weather ranging from 0 to 45 °C and 0 to 100% relative humidity, and in vibration-intensive environments such as moving helicopters. The instrument has made field measurements of radiance and emissivity for 3 yr without loss of optical alignment. We describe the design of the instrument and discuss methods used to calibrate spectral radiance and calculate spectral emissivity from radiance measurements. Examples of emissivity spectra are shown for both the 3–5-µm and 8–14-µm atmospheric windows.
Key words: Fourier transform infrared spectroradiometer, portable spectrometer, infrared radiance
measurement, radiometric calibration, spectral emissivity calculation.
Reference: Korb, A.R., P. Dybwad, W. Wadsworth, and J.W. Salisbury, 1996, Portable Fourier Transform Infrared Spectrometer for Field Measurements of Radiance and Emissivity, Applied Optics, v.35, p.1679-1692. http://www.dpinstruments.com/papers/applied_optics_update.pdf
Copyright 1996 Optical Society of America
Monday, February 23, 2009
Wednesday, February 11, 2009
Global Infrared Land Surface Emissivity:
UW-Madison Baseline Fit Emissivity Database
From the University of Wisconsin CIMSS data section: http://cimss.ssec.wisc.edu/iremis/
Downloading the dataset:
UW Baseline Fit Emissivity Database: Version 2.0 (released July 2006) and Version 3.0 (released March 2008):
Registration is required to obtain the data.
Readme
The JAMC paper that details the baseline fit procedure for deriving the database and its application to atmospheric retrievals is available at the website
http://cimss.ssec.wisc.edu/iremis/
Please reference this paper for any use of the database:
Seemann, S.W., E. E. Borbas, R. O. Knuteson, G. R. Stephenson, H.-L. Huang, 2007:
Development of a Global Infrared Land Surface Emissivity Database for Application to
Clear Sky Sounding Retrievals from Multi-spectral Satellite Radiance Measurements.
J. of Appl. Meteor. and Climatol., Vol. 47, 108-123.
From the University of Wisconsin CIMSS data section: http://cimss.ssec.wisc.edu/iremis/
This global database of infrared land surface emissivity is derived using input from the Moderate Resolution Imaging Spectroradiometer (MODIS) operational land surface emissivity product (MOD11). The baseline fit method (Seemann et al., 2007), based on a conceptual model developed from laboratory measurements of surface emissivity, is applied to fill in the spectral gaps between the six emissivity wavelengths available in MOD11.
Downloading the dataset:
UW Baseline Fit Emissivity Database: Version 2.0 (released July 2006) and Version 3.0 (released March 2008):
Registration is required to obtain the data.
Readme
The JAMC paper that details the baseline fit procedure for deriving the database and its application to atmospheric retrievals is available at the website
http://cimss.ssec.wisc.edu/iremis/
Please reference this paper for any use of the database:
Seemann, S.W., E. E. Borbas, R. O. Knuteson, G. R. Stephenson, H.-L. Huang, 2007:
Development of a Global Infrared Land Surface Emissivity Database for Application to
Clear Sky Sounding Retrievals from Multi-spectral Satellite Radiance Measurements.
J. of Appl. Meteor. and Climatol., Vol. 47, 108-123.
Monday, February 9, 2009
Thermophysical properties and normal spectral emittance of Iridium up to 3500 K
"Thermophysical properties and normal spectral emittance of Iridium up to 3500 K",
International Journal of Thermophysics Vol. 28(2), p. 697-710, http://dx.doi.org/10.1007/s10765-007-0188-9, (2007) by C. Cagran, G. Pottlacher
C. Cagran1 and G. Pottlacher1 Contact Information
(1) Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, 8010 Graz, Austria
Published online: 10 May 2007
"An ohmic pulse-heating experiment together with radiometry and ?s-photopolarimetry is deployed at the Institute of Experimental Physics, Graz University of Technology, to obtain temperature-dependent thermophysical properties of conducting samples in the solid and molten states..."
"This experimental setup has been used within the present work to gather data for solid and liquid iridium. Results for both thermophysical properties, as well as the normal spectral emittance obtained at a wavelength of 684.5 nm up to 3500 K are reported. The newly obtained values for iridium are presented in graphical and tabular form and compared to available literature data. The uncertainties for all reported properties are stated and it follows that, considering these expanded uncertainties, the recent data are in very good agreement with literature sources. Mutually motivated by these good results and by the scarce (if any) data available for the liquid state, the thermal conductivity and thermal diffusivity of liquid iridium are estimated by means of the Wiedemann–Franz law."
Keywords: ellipsometry - iridium - normal spectral emittance - pulse-heating - thermal conductivity - thermal diffusivity - thermophysical properties
International Journal of Thermophysics Vol. 28(2), p. 697-710, http://dx.doi.org/10.1007/s10765-007-0188-9, (2007) by C. Cagran, G. Pottlacher
C. Cagran1 and G. Pottlacher1 Contact Information
(1) Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, 8010 Graz, Austria
Published online: 10 May 2007
"An ohmic pulse-heating experiment together with radiometry and ?s-photopolarimetry is deployed at the Institute of Experimental Physics, Graz University of Technology, to obtain temperature-dependent thermophysical properties of conducting samples in the solid and molten states..."
"This experimental setup has been used within the present work to gather data for solid and liquid iridium. Results for both thermophysical properties, as well as the normal spectral emittance obtained at a wavelength of 684.5 nm up to 3500 K are reported. The newly obtained values for iridium are presented in graphical and tabular form and compared to available literature data. The uncertainties for all reported properties are stated and it follows that, considering these expanded uncertainties, the recent data are in very good agreement with literature sources. Mutually motivated by these good results and by the scarce (if any) data available for the liquid state, the thermal conductivity and thermal diffusivity of liquid iridium are estimated by means of the Wiedemann–Franz law."
Keywords: ellipsometry - iridium - normal spectral emittance - pulse-heating - thermal conductivity - thermal diffusivity - thermophysical properties
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