Search Publications
Phase compensation of MARSIS subsurface sounding data and estimation of ionospheric properties: New insights from SHARAD results
Campbell, Bruce A.; Watters, Thomas R.
Subsurface radar sounding observations by the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) and Shallow Radar (SHARAD) instruments are affected by ionospheric phase distortions that lead to image blurring and delay offsets. Based on experience with SHARAD image correction, we propose that ionospheric blurring in MARSIS radar…
Hydrological and sedimentary analyses of well-preserved paleofluvial-paleolacustrine systems at Moa Valles, Mars
Hauber, Ernst; Di Achille, Gaetano; Ori, Gian Gabriele +2 more
Moa Valles is a well-preserved, likely Amazonian (younger than 2 Ga old), paleodrainage system that is nearly 300 km long and carved into ancient highland terrains west of Idaeus Fossae. The fluvial system apparently originated from fluidized ejecta blankets, and it consists of a series of dam breach paleolakes with associated fan-shaped sedimenta…
Characterization of the permittivity of controlled porous water ice-dust mixtures to support the radar exploration of icy bodies
Thomas, N.; Brouet, Y.; Pommerol, A. +6 more
The internal properties of porous and icy bodies in the solar system can be investigated by ground-penetrating radars (GPRs), like the COmet Nucleus Sounding Experiment by Radiowave Transmission instrument on board the Rosetta spacecraft which has sounded the interior of the nucleus of comet 67P/Churyumov-Gerasimenko. Accurate constraints on the p…
Constraints on the formation and properties of a Martian lobate debris apron: Insights from high-resolution topography, SHARAD radar data, and a numerical ice flow model
Parsons, Reid; Holt, John
Lobate debris aprons (LDAs) are midlatitude deposits of debris-covered ice formed during one or more periods of glaciation during the Amazonian period. However, little is known about the climate conditions that led to LDA formation. We explore a hypothesis in which a single, extended period of precipitation of ice on the steep slopes of Euripus Mo…
Lithospheric flexure and gravity spreading of Olympus Mons volcano, Mars
Williams, D. A.; Platz, T.; Dumke, A. +5 more
The structural architecture of large volcanoes is governed substantially by gravity-driven deformation that is manifest as distinct processes such as basement flexure or volcanic spreading. Temporal effects and the mutual interplay of these processes have been investigated only to a limited extent, and so we present novel numerical models of the t…
A photochemical model of the dust-loaded ionosphere of Mars
Montmessin, F.; O'Brien, K.; Michael, M. +5 more
The ionization of the lower Martian atmosphere and the presence of charged species are fundamental in the understanding of atmospheric electricity phenomena, such as electric discharges, large-scale electric currents, and Schumann resonances. The present photochemical model of the lower ionosphere of Mars (0-70 km) is developed to compute the conc…
Stratigraphy and formation of clays, sulfates, and hydrated silica within a depression in Coprates Catena, Mars
Weitz, Catherine M.; Bishop, Janice L.
We investigate the morphology, mineralogy, and stratigraphy of light-toned layered deposits within a trough of Coprates Catena, centered at -15°N, 300°E. One of the deposits in the eastern portion of the trough contains numerous hydrated minerals, including Al-phyllosilicates, Fe/Mg-phyllosilicates, hydrated silica, hydrated sulfates, jarosite and…
Vortices in Saturn's Northern Hemisphere (2008-2015) observed by Cassini ISS
West, Robert A.; Porco, Carolyn C.; Baines, Kevin H. +12 more
We use observations from the Imaging Science Subsystem on Cassini to create maps of Saturn's Northern Hemisphere (NH) from 2008 to 2015, a time period including a seasonal transition (i.e., spring equinox in 2009) and the 2010 giant storm. The processed maps are used to investigate vortices in the NH during the period of 2008-2015. All recorded vo…
CO2 non-LTE limb emissions in Mars' atmosphere as observed by OMEGA/Mars Express
Gondet, B.; Forget, F.; Altieri, F. +7 more
We report on daytime limb observations of Mars upper atmosphere acquired by the OMEGA instrument on board the European spacecraft Mars Express. The strong emission observed at 4.3 µm is interpreted as due to CO2 fluorescence of solar radiation and is detected at a tangent altitude in between 60 and 110 km. The main value of OMEGA …
Potential vorticity of the south polar vortex of Venus
Hueso, R.; Sánchez-Lavega, A.; García Muñoz, A. +1 more
Venus' atmosphere shows highly variable warm vortices over both of the planet's poles. The nature of the mechanism behind their formation and properties is still unknown. Potential vorticity is a conserved quantity when advective processes dominate over friction and diabatic heating and is a quantity frequently used to model balanced flows. As a s…