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Small Scale Roughness of the Moon: Inversion of Diviner Measurements. Paul Hayne 1 , Oded Aharonson 2,1 , Joshua Bandfield 3 , Meg Rosenburg 1 , David Paige 4 , and the Diviner Team 1 California Institute of Technology 2 Weizmann Institute of Science 3 University of Washington
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Small Scale Roughness of the Moon: Inversion of Diviner Measurements Paul Hayne1, Oded Aharonson2,1, Joshua Bandfield3, Meg Rosenburg1, David Paige4, and the Diviner Team 1California Institute of Technology 2Weizmann Institute of Science 3University of Washington 4University of California, Los Angeles
Temperatures in Shadow and Sunlight Sunlit surfaces nearly in radiative equilibrium (400 K at normal solar incidence) Shadows much colder; conduction from subsurface balances thermal emission (100 K at midnight)
Infrared Emission from a Rough Surface Emission at shorter wavelengths dominated by warmer facets (two Diviner channels indicated by arrows)
Surface Roughness Example: Apollo 11 • Best-fit RMS slope 20 – 30 • Model fit quality changes with local time… poor modeling of shadow temperatures?
Comparison to Apollo Landing Sites Helfenstein and Shepard (1999) RMS slope Scale (millimeters) Problem: We should not be able to see roughness below the thermal skin depth of a few centimeters, yet RMS slopes match sub-millimeter values from Apollo…
Preliminary Roughness Map RMS surface slopes, derived from channels 4 and 7, corrected for emissivity (We are working on a global map, but emissivity correction is challenging at higher latitudes.)
Preliminary Roughness Map LOLA 17-m baseline slopes (Rosenburg et al. 2011)