Physics
Scientific paper
Dec 2004
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2004agufm.p21a0212w&link_type=abstract
American Geophysical Union, Fall Meeting 2004, abstract #P21A-0212
Physics
5410 Composition, 5416 Glaciation, 5464 Remote Sensing, 5494 Instruments And Techniques
Scientific paper
Recent observations and modeling indicate widespread, near-surface ground ice on Mars, but leave its depth of occurrence and form (e.g., interstitial or massive) significantly uncertain. We show here that the propagation of surface temperature variations to depth, together with thermal microwave emission that originates from commensurate depths and which is observed over time, provide a basis to probe the nature and depth of ice deposits. We utilize analogs in Antarctic Dry Valley soils, where time-resolved temperature profiles reveal that surface temperature variations on daily and longer time scales propagate to depths of decimeters and greater, especially in desiccated, fine-grained (low thermal inertia) soils. For example, diurnal surface variations of 10C produce 3C variations at 20 cm depth in desiccated soil in Beacon Valley. Ice-cemented (but not saturated) soils in Victoria Valley, by contrast, show diurnal variations (with similar thermal forcing) of only a fraction of a degree at similar depths. Thus thermal microwave emission at wavelengths that probe to decimeter depths will also differ between cases. We compute expected properties of microwave brightness temperature time series using measurements of mineral dielectric properties (including observations of Martian analogs), mixing formulae to account for ice content, and recent theory from Winebrenner et al. (Annals of Glaciology, v 39, 2004). According to the latter theory, a single parameter governs the relationship between surface and brightness temperature time series. That parameter is a characteristic time-scale given by the square of the microwave emission depth-scale over the soil thermal diffusivity. Calculations show that the characteristic time-scale increases strongly with increasing ice content and with decreasing burial depth. Based on such variations, we outline a remote sensing method to estimate characteristics of ground ice based on infrared surface temperature and microwave brightness temperature observations with specified temporal resolution and duration. Existing satellite observations of spatially extensive terrestrial analogs can be used to develop this method for flight-readiness.
Hallet Bernard
Sletten Ronald S.
Winebrenner Dale P.
No associations
LandOfFree
Toward Probing Martian Ground Ice Using Microwave Emission: Data and Calculations from Antarctic Dry Valley Analogs does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Toward Probing Martian Ground Ice Using Microwave Emission: Data and Calculations from Antarctic Dry Valley Analogs, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Toward Probing Martian Ground Ice Using Microwave Emission: Data and Calculations from Antarctic Dry Valley Analogs will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1647037