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T.F. Mao (Caltech/NRAO), B.J. Butler (NRAO), M.A. Slade, A.F.C. Haldemann (JPL), D.O. Muhleman (Caltech)
The properties of the martian polar ice caps, volcanic and other regions (e.g. "Stealth") can be constrained with radar observations. Previous Goldstone/VLA radar observations indicated differences in the reflectivity of the two residual polar ice caps: 1988 observations showed the south residual cap (SPRIC) as a bright radar reflector whereas 1992/93 observations showed little radar enhancement from the north residual cap (NPRIC). This effect was attributed to a combination of different viewing geometry, martian season, and intrinsic scattering behavior. Similar geometries and seasons in 1999 as 1988 allowed observations during that opposition to investigate these three effects; though the NPRIC radar reflectivity was increased, reflectivity levels did not reach those of the SPRIC in 1988. In addition, all previous Goldstone/VLA radar observations have shown "Stealth" as a major radar-dark feature; the possible presence of extensive ash and dust deposits in the Hellas Basin suggest the presence of other similar radar-dark regions such as Argyre Planitia. Hellas was not covered well in previous observations because of geometry and observational timing.
Mars was observed during the 2003 opposition using the joint Goldstone/VLA 3.5-cm radar instrument. Data from these experiments can be used to verify the uniqueness, or lack thereof concerning the 1988 SPRIC reflectivity, compare Argyre Planitia and Hellas Basin to "Stealth", and improve models of the reflectivity of the volcanic regions. Results from these observations will be presented and compared to those from the previous experiments.
The NRAO is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc. This work was supported by the NSF REU program at NRAO.
The author(s) of this abstract have provided an email address for comments about the abstract: tmao@astro.caltech.edu
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Bulletin of the American Astronomical Society, 37 #3
© 2004. The American Astronomical Soceity.