Showing papers on "Polarimetry published in 1983"

Video polarimetry: a new imaging technique in atmospheric science

Abstract: An imaging polarimeter has been built to study the polarization of solar radiation (λ = 550 nm) scattered and reflected from the natural environment. The instrument generates false color images as multiparameter display of the degree of polarization, azimuth of polarization, and the radiance. These video signals can be digitized into a computer-compatible format. As an example of application, the polarization properties of light reflected from a lake and its environment are discussed here.

Polarimetry of comets: a review

Abstract: Some attempts of polarimetric sounding of Comet Halley will be undertaken from the flyby probes. In order to facilitate the final planning and the future interpretation of these experiments we have done a thorough analysis of practically all available polarimetric observations. An emphasis is made on interpretation attempts and their discussion. The results of the phase dependence of polarization investigations are presented covering a wide range of phase angles α. The chief peculiarities of this dependence are: maximum polarization at α = 90‡, diminishing through zero at α ≈ 20‡, negative values up to several per cent and a final growth to zero at zero α. A division into “gaseous” and “dusty” comets on polarimetric basis is revealed. The wavelength dependence of polarization is discussed. The numerous results of detailed polarimetry are compared to the negative results of attempts to detect the elliptical polarization. New observational problems arising from the evidence given by the negative polarization at small phase angles and by the “opposition effect” recently discovered are discussed.

Polarization Scattering Matrices for Polarimetric Radar

Abstract: : A study of radar cross section in terms of transmitted and received polarizations is presented to aid in assessing the potential for polarimetric radar. The polarization scattering matrices for various options are related.

Circular Polarimetry of Am-Herculis

Abstract: Circular polarimetry in the red and simultaneous photometric observations in the UBVRI bands during the period June 1-3, 1981, are discussed. The peak value of negative circular polarization PV ∿ -15% is stronger than observed in 1976–79. Variations in the shape of the polarization and light curves occur from night to night. The positive crossover and reversal of the sign of the circular polarization are only marginal. A probable explanation of the short term variations seems to be the changing shape and position of the accretion columns with respect to the magnetic axis.

Antenna polarization and scattering matrix measurements in mixed polarization bases

Abstract: The ambiguity in the sense of polarization measurement, using amplitude measurements only, comes When four antennas, with polarization of each, located in the same great circle on the Poincare polarization sphere are employed. A mathematical proof of the fact that correct sense of polarization is impossible to determine when four antenna polarizations in the same great circle on the polarization sphere is presented. In great detail, the mathematical and physical relationships are derived for the prescription of complete scattering matrix measurements, i.e., what kind of measurements need to be performed for extracting complete polarimetric information so that the relative phase scattering matrix S(A,B) for any polarization vector base can be reconstructed. It is the prime objective of this detailed analysis to assist developing efficient polarimetric radar measurement design concepts.