Use of Kirchoff's law to compensate for scan-dependent gain and polarization effects in a thermal infrared radiometer

Christopher W. Palmer

doi:10.1117/12.265451

27 January 1997 Use of Kirchoff's law to compensate for scan-dependent gain and polarization effects in a thermal infrared radiometer

Christopher W. Palmer

Author Affiliations +

Proceedings Volume 2957, Advanced and Next-Generation Satellites II; (1997) https://doi.org/10.1117/12.265451
Event: Satellite Remote Sensing III, 1996, Taormina, Italy

Abstract

Thermal infrared and microwave satellite radiometers are typically calibrate in-flight using a space view as a radiometric zero, and a view to a blackbody as a full-scale reference view. This study refers specifically to the high- resolution dynamics limb sounder, an infrared filter radiometer under development for the NASA EOS-Chem payload, but some aspects of it are of general interest for radiometric calibration. Instruments of this type typically have scan patterns generated by a plane scan mirror near the front of the optical train. The calibration views are thus acquired with a slightly different optical configuration from each other, and from the required scene views, raising questions about scan-dependent gain and polarization effects. The present paper establishes a formalism for handling polarization issues in radiometers, adapted to a geometrical ray-tracing modeling approach. Using this formalism, it is shown that the gain errors are substantially cancelled provided the scanning geometry permits a space view with a very similar optical arrangement to the required scene views, and the blackbody, intermediate mirror and scan mirror can be maintained at the same temperature. This cancellation follows from the application of Kirchoff's law, and is thus a robust conclusion. Explicit general expressions are given for the residual errors arising with non-zero temperature differences.

Citation Download Citation

Christopher W. Palmer "Use of Kirchoff's law to compensate for scan-dependent gain and polarization effects in a thermal infrared radiometer", Proc. SPIE 2957, Advanced and Next-Generation Satellites II, (27 January 1997); https://doi.org/10.1117/12.265451

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available