Modeling variations in near-infrared spectra caused by the coherent backscattering effect

Abstract We study a new optical effect, a spectral manifestation of coherent backscattering, which reveals itself as systematic variations in the depth of absorption bands with changing phase angle. We used Cassini VIMS near-infrared spectra of Saturn's icy satellite Rhea in order to identify and characterize the spectral change with phase angle, focusing on the change in the depth of water–ice absorption bands. To model realistic characteristics of the surfaces of icy satellites, which are most likely covered by micron-sized densely packed particles, we perform simulations using a theoretical approach based on direct computer solutions of the macroscopic Maxwell equations. Our results show that this approach can reproduce the observed phase-angle variations in the depth of the absorption bands. The modeled changes in the absorption bands are strongly affected by physical properties of the regolith, especially by the size and packing density of the ice particles. Thus, the phase-angle spectral variations demonstrate a promising remote-sensing capability for studying properties of the surfaces of icy bodies and other objects that exhibit a strong coherent backscattering effect.

[1]  E. V. Petrova,et al.  Modeling of opposition effects with ensembles of clusters: Interplay of various scattering mechanisms , 2007 .

[2]  Richard P. Binzel,et al.  Phase relations of high albedo asteroids: The unusual opposition brightening of 44 Nysa and 64 Angelina☆ , 1989 .

[3]  Linda J. Spilker,et al.  The Opposition Effect in Simulated Planetary Regoliths. Reflectance and Circular Polarization Ratio Change at Small Phase Angle , 2000 .

[4]  D. T. Thompson,et al.  Europa's phase curve: Implications for surface structure , 1991 .

[5]  Bruce Hapke,et al.  Coherent backscatter and the radar characteristics of outer planet satellites , 1990 .

[6]  M. Mishchenko,et al.  Can weak localization of photons explain the opposition effect of Saturn's rings? , 1992 .

[7]  M. Mishchenko,et al.  Photometric and Polarimetric Opposition Phenomena Exhibited by Solar System Bodies , 2002 .

[8]  Michael I. Mishchenko,et al.  Multiple scattering, radiative transfer, and weak localization in discrete random media: Unified microphysical approach , 2008 .

[9]  E. Akkermans,et al.  Mesoscopic physics of photons , 2004 .

[10]  J. Piironen,et al.  The Opposition Effect and Negative Polarization of Structural Analogs for Planetary Regoliths , 2002 .

[11]  Planetary Regolith Microstructure: An Unexpected Opposition Effect Result , 2004 .

[12]  M. I. Mishchenko,et al.  Coherent backscatter and the opposition effect for E-type asteroids , 1993 .

[13]  K. Muinonen.  Coherent backscattering of light by complex random media of spherical scatterers: numerical solution , 2004 .

[14]  Backscattering from snow and ice: Laboratory and field measurements , 2003 .

[15]  G. Videen,et al.  Optics of cosmic dust , 2002 .

[16]  M. Mishchenko.  On the nature of the polarization opposition effect exhibited by Saturn's rings , 1993 .

[17]  S. Warren,et al.  Optical constants of ice from the ultraviolet to the microwave. , 1984, Applied optics.

[18]  Roger N. Clark,et al.  Water frost and ice - The near-infrared spectral reflectance 0.65-2.5 microns. [observed on natural satellites and other solar system objects , 1981 .

[19]  Bruce Hapke,et al.  Bidirectional Reflectance Spectroscopy: 5. The Coherent Backscatter Opposition Effect and Anisotropic Scattering , 2002 .

[20]  N. M. Shakhovskoy,et al.  Polarimetric remote sensing of Solar System objects , 2010, 1010.1171.

[21]  J. Goguen,et al.  How to compare the surface of Io to laboratory samples , 1978 .

[22]  Karri Muinonen,et al.  Surface Properties of Kuiper Belt Objects and Centaurs from Photometry and Polarimetry , 2008 .

[23]  Michael I. Mishchenko,et al.  Calculation of the T matrix and the scattering matrix for ensembles of spheres , 1996 .

[24]  Deborah L. Domingue,et al.  NEAR Infrared Spectrometer Photometry of Asteroid 433 Eros , 2002 .

[25]  A. Ishimaru,et al.  Retroreflectance from a dense distribution of spherical particles , 1984 .

[26]  Jennifer L. Piatek,et al.  A quantitative test of the ability of models based on the equation of radiative transfer to predict the bidirectional reflectance of a well-characterized medium , 2009 .

[27]  B. Buratti,et al.  Disk-integrated bolometric Bond albedos and rotational light curves of saturnian satellites from Cassini Visual and Infrared Mapping Spectrometer , 2010 .

[28]  M. Mishchenko,et al.  DIRECT SOLUTIONS OF THE MAXWELL EQUATIONS EXPLAIN OPPOSITION PHENOMENA OBSERVED FOR HIGH-ALBEDO SOLAR SYSTEM OBJECTS , 2009 .

[29]  William D. Smythe,et al.  Low phase angle laboratory studies of the opposition effect: search for wavelength dependence , 2002 .

[30]  Brian Cairns,et al.  Multiple scattering by random particulate media: exact 3D results. , 2007, Optics express.

[31]  A. Lacis,et al.  Multiple Scattering of Light by Particles: Radiative Transfer and Coherent Backscattering , 2006 .

[32]  R. H. Brown,et al.  The Cassini Visual And Infrared Mapping Spectrometer (Vims) Investigation , 2004 .

[33]  M. Mishchenko.  Diffuse and coherent backscattering by discrete random media—I. Radar reflectivity, polarization ratios, and enhancement factors for a half-space of polydisperse, nonabsorbing and absorbing spherical particles , 1996 .

[34]  Mishchenko.  Polarization effects in weak localization of light: Calculation of the copolarized and depolarized backscattering enhancement factors. , 1991, Physical review. B, Condensed matter.

[35]  Sanna Kaasalainen,et al.  Small-angle goniometry for backscattering measurements in the broadband spectrum. , 2005, Applied optics.

[36]  M. Mishchenko,et al.  Approximate calculation of coherent backscattering for semi-infinite discrete random media , 2009 .

[37]  V. Tishkovets.  Multiple scattering of light by a layer of discrete random medium: backscattering , 2002 .

[38]  L. Kolokolova,et al.  IMPACT OF COHERENT BACKSCATTERING ON THE SPECTRA OF ICY SATELLITES OF SATURN AND THE IMPLICATIONS OF ITS EFFECTS FOR REMOTE SENSING , 2010 .

[39]  F. Franklin,et al.  Optical properties of Saturn's rings. II. Two-color phase curves of the 2 bright rings. , 1965 .

[40]  Coherent backscattering of light by a layer of discrete random medium , 2004 .

[41]  Dale P. Cruikshank,et al.  The solar system beyond Neptune , 2008 .

[42]  Wolf,et al.  Weak localization and coherent backscattering of photons in disordered media. , 1985, Physical review letters.

[43]  Karri Muinonen,et al.  Light scattering by inhomogeneous media : backward enhancement and reversal of linear polarization , 1990 .

[44]  Michele Dami,et al.  The Visual and Infrared Mapping Spectrometer for Cassini , 1996, Optics & Photonics.