In:
Journal of Geophysical Research: Planets, American Geophysical Union (AGU), Vol. 99, No. E10 ( 1994-10-25), p. 21143-21152
Abstract:
We present the first comprehensive discussion of the south seasonal polar cap spectra obtained by the Mariner 7 infrared spectrometer in the short‐wavelength region (2–4 μm). In addition, we correlate the infrared spectra with images acquired by the wide‐angle camera. Significant spectral variation is noted in the cap interior and regions of varying water frost abundance, CO 2 ice/frost cover, and CO 2 ‐ice path length can be distinguished. Many of these spectral variations correlate with heterogeneity noted in the camera images, but certain significant infrared spectral variations are not discernible in the visible. We use simple reflectance models to classify the observed spectral variations into four regions. Region I is at the cap edge, where there is enhanced absorption beyond 3 μm inferred to be caused by an increased abundance of water frost. The increase in water abundance over that in the interior is on the level of a few parts per thousand or less. Region II is the typical cap interior characterized by spectral features of CO 2 ice at grain sizes of several millimeters to centimeters. These spectra also indicate the presence of water frost at the parts per thousand level. A third, unusual region (III), is defined by three spectra in which weak CO 2 absorption features are as much as twice as strong as in the average cap spectra and are assumed to be caused by an increased path length in the CO 2 . Such large paths are inconsistent with the high reflectance in the visible and at 2.2 μm and suggest layered structures or deposition conditions that are not accounted for in current reflectance models. The final region (IV) is an area of thinning frost coverage or transparent ice well in the interior of the seasonal cap. These spectra are a combination of CO 2 and ground signatures.
Type of Medium:
Online Resource
ISSN:
0148-0227
Language:
English
Publisher:
American Geophysical Union (AGU)
Publication Date:
1994
detail.hit.zdb_id:
2033040-6
detail.hit.zdb_id:
3094104-0
detail.hit.zdb_id:
2130824-X
detail.hit.zdb_id:
2016813-5
detail.hit.zdb_id:
2016810-X
detail.hit.zdb_id:
2403298-0
detail.hit.zdb_id:
2016800-7
detail.hit.zdb_id:
161666-3
detail.hit.zdb_id:
161667-5
detail.hit.zdb_id:
2969341-X
detail.hit.zdb_id:
161665-1
detail.hit.zdb_id:
3094268-8
detail.hit.zdb_id:
710256-2
detail.hit.zdb_id:
2016804-4
detail.hit.zdb_id:
3094181-7
detail.hit.zdb_id:
3094219-6
detail.hit.zdb_id:
3094167-2
detail.hit.zdb_id:
2220777-6
detail.hit.zdb_id:
3094197-0
SSG:
16,13
Permalink