Water frost and ice - The near-infrared spectral reflectance 0.65-2.5 microns. [observed on natural satellites and other solar system objects

The spectral reflectance of water frost and frost on ice as a function of temperature and grain size is presented with 1½% spectral resolution in the 0.65- to 2.5-μm wavelength region. The well-known 2.0-, 1.65-, and 1.5-μm solid water absorption bands are precisely defined along with the little studied 1.25-μm band and the previously unidentified (in reflectance) 1.04-, 0.90-, and 0.81-μm absorption bands. The 1.5-μm band complex is quantitatively analyzed using a nonlinear least squares algorithm to resolve the band into four Gaussian components as a function of grain size and temperature. It is found that the 1.65 μm component, which was thought to be a good temperature sensor, is highly grain size dependent and poorly suited to temperature sensing. Another Gaussian component appears to show a dependence of width on grain size while being independent of temperature. The relative apparent band depths are different for frost layers on ice than for thick layers of frost and may explain the apparent band depths seen in many planetary reflectance spectra.

[1]  W. Smythe,et al.  Frost spectra: Comparison with Jupiter's Satellites , 1974 .

[2]  R. Clark,et al.  The rings of Saturn - New near-infrared reflectance measurements and a 0. 326-4. 08 micron summary , 1980 .

[3]  R. N. Clark,et al.  Ganymede, Europa, Callisto, and Saturn's rings: Compositional analysis from reflectance spectroscopy☆ , 1980 .

[4]  H. Kieffer.  Near infrared spectral reflectance of simulated Martian frosts , 1968 .

[5]  H. Kieffer.  Spectral reflectance of CO2-H2O Frosts , 1970 .

[6]  R. N. Clark,et al.  A LARGE-SCALE INTERACTIVE ONE-DIMENSIONAL ARRAY PROCESSING SYSTEM , 1980 .

[7]  R. Clark,et al.  The spectral reflectance of water-mineral mixtures at low temperatures. [observed on natural satellites and other solar system objects] , 1981 .

[8]  U. Fink,et al.  Temperature dependence of the water-ice spectrum between 1 and 4 microns - Application to Europa, Ganymede and Saturn's rings , 1975 .

[9]  G. Rieke,et al.  Surface Compositions of the Satellites of Saturn from Infrared Photometry , 1976 .

[10]  E. Whalley.  A detailed assignment of the O–H stretching bands of ice I , 1977 .

[11]  C. Pilcher,et al.  Saturn's Rings: Identification of Water Frost , 1970, Science.

[12]  R. Clark,et al.  Mars - Near-infrared spectral reflectance and compositional implication , 1978 .

[13]  S. Ridgway,et al.  Galilean Satellites: Identification of Water Frost , 1972, Science.

[14]  R. Clark,et al.  The Galilean satellites: New near-infrared spectral reflectance measurements (0.65–2.5 μm) and a 0.325–5 μm summary , 1980 .

[15]  U. Fink,et al.  Infrared spectra of the satellites of Saturn - Identification of water ice on Iapetus, Rhea, Dione, and Tethys , 1976 .