Lambert albedo retrieval and analyses over Aram Chaos from OMEGA hyperspectral imaging data
Article first published online: 29 AUG 2012
©2012. American Geophysical Union. All Rights Reserved.
Journal of Geophysical Research: Planets (1991–2012)
Volume 117, Issue E11, November 2012
How to Cite
2012), Lambert albedo retrieval and analyses over Aram Chaos from OMEGA hyperspectral imaging data, J. Geophys. Res., 117, E00J11, doi:10.1029/2012JE004056., , , , , , and (
- Issue published online: 29 AUG 2012
- Article first published online: 29 AUG 2012
- Manuscript Accepted: 18 JUL 2012
- Manuscript Revised: 15 JUL 2012
- Manuscript Received: 27 JAN 2012
- Aram Chaos;
- Lambert albedo;
- radiative transfer model
 The DISORT radiative transfer model was used to retrieve Lambert albedos from 0.4 to 4.0 μm over hydrated sulfate deposits in Aram Chaos for the Mars Express OMEGA instrument. Albedos were also retrieved for a relatively anhydrous area to the north to use as a control for comparison to the hydrated sulfate spectra. Atmospheric gases and aerosols were modeled, along with both solar and thermal radiance contributions and retrieved Lambert albedos are similar for multiple OMEGA observations over the same areas. The Lambert albedo spectra show that the control area is dominated by electronic transition bands due to nanophase iron oxides and low-calcium orthopyroxenes, together with the ubiquitous 2.98μm band due in part to water adsorbed onto particle surfaces. The retrieved Lambert albedos for Aram Chaos show an enhanced 2.98 μm water band and bands located at 0.938, 1.46, 1.96, and 2.41 μm. We infer the presence of nanophase iron oxides, schwertmannite, and starkeyite based on consideration of these band locations, inferred electronic and vibrational absorptions, stability under Mars conditions, and pathways for formation. This mineral assemblage, together with gray, crystalline hematite previously detected from TES data (Glotch and Christensen, 2005), can be explained as a result of iron oxidation and evaporation of iron-, magnesium-, and sulfur-rich fluids during periods of rising groundwater.