7549(  1) - 12/14/96 01:03  - [  0]

    PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS   ST ScI Use Only
                                                       ID:      7549
                                                       Version: 1
                                                       Check-in Date: 13-Dec-1996
                                                                      18:22:54

1.Proposal Title:
A New Look at Martian Ice Clouds
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2. Scientific Category   3. Proposal For  4. Cycle
SOLAR SYSTEM                AR               7
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5. Investigators
                                                                                     Contact?
    PI: Michael Wolff                     Space Science Institute

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6. Abstract

A fundamental problem in our current understanding of the Martian atmosphere and
climate is the role of water ice clouds. Until recently, the community's view had
been primarily shaped by the observations obtained during the Viking missions.
However, recent microwave temperature and water profiling measurements indicate that
the warm, dusty period observed by Viking was quite possibly atypical. More
specifically, Clancy et al. find that the current atmosphere is approximately 15-20
K colder than the Viking temperature measurements obtained for the same seasons. A
natural consequence of a dryer, cooler Martian climate would be the presence of a
global mid-latitude cloud belt, which has in fact been observed in the limited
analysis performed by Clancy et al. of several HST images (but not seen in the
Viking data). It is not unreasonable to consider that the effects of low-to-mid
latitude water vapor saturation at low altitudes may play a significantly more
important role in the current climatic state than previously believed. The key to
enhancing our knowledge is the long-term synoptic monitoring of atmospheric
phenomena. The combination of poor spatial resolution and other telluric effects
necessitates the use of spacecraft data. Fortunately, an excellent dataset already
exists in data archives of the Hubble Space Telescope. I propose to analyze these
data (taken 1990-1995) in order to characterize the spatial and temporal variability
of atmospheric cloud processes, including interannual variations.
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  Blocking Factor: 10
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                                                7549(  1) - 12/14/96 01:03  - [  1]

            Summary Form for Proposal  7549

  Item                         Used in this proposal
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  Proposal Category            AR
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  Scientific Category          SOLAR SYSTEM
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