Open AccessLunar equatorial surface temperatures and regolith properties from the Diviner Lunar Radiometer Experiment
Author(s) -
Vasavada Ashwin R.,
Bandfield Joshua L.,
Greenhagen Benjamin T.,
Hayne Paul O.,
Siegler Matthew A.,
Williams JeanPierre,
Paige David A.
Publication year - 2012
Publication title -
journal of geophysical research: planets
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2011je003987
Subject(s) - regolith , radiometer , radiance , albedo (alchemy) , atmospheric sciences , environmental science , daytime , brightness temperature , radiative transfer , remote sensing , geology , brightness , astrobiology , physics , astronomy , optics , art , performance art , art history
The Diviner Lunar Radiometer Experiment onboard the Lunar Reconnaissance Orbiter has measured solar reflectance and mid‐infrared radiance globally, over four diurnal cycles, at unprecedented spatial and temporal resolution. These data are used to infer the radiative and bulk thermophysical properties of the near‐surface regolith layer at all longitudes around the equator. Normal albedos are estimated from solar reflectance measurements. Normal spectral emissivities relative to the 8‐ μ m Christiansen Feature are computed from brightness temperatures and used along with albedos as inputs to a numerical thermal model. Model fits to daytime temperatures require that the albedo increase with solar incidence angle. Measured nighttime cooling is remarkably similar across longitude and major geologic units, consistent with the scarcity of rock exposures and with the widespread presence of a near‐surface layer whose physical structure and thermal response are determined by pulverization through micrometeoroid impacts. Nighttime temperatures are best fit using a graded regolith model, with a ∼40% increase in bulk density and an eightfold increase in thermal conductivity (adjusted for temperature) occurring within several centimeters of the surface.