Search Publications
Periodic variations of oxygen EUV dayglow in the upper atmosphere of Venus: Hisaki/EXCEED observations
Fedorov, A.; Futaana, Y.; Zhang, T. L. +14 more
Using the Extreme Ultraviolet Spectroscope for Exospheric Dynamics (EXCEED) aboard Hisaki and the Solar Extreme Ultraviolet Monitor on the Solar and Heliospheric Observatory, we investigate variations of the extreme ultraviolet (EUV) dayglow brightness for OII 83.4 nm, OI 130.4 nm, and OI 135.6 nm in the Venusian upper atmosphere observed in March…
Limited role for thermal erosion by turbulent lava in proximal Athabasca Valles, Mars
Williams, David A.; Dundas, Colin M.; Keszthelyi, Laszlo P. +1 more
The Athabasca Valles flood lava is among the most recent (<50 Ma) and best preserved effusive lava flows on Mars and was probably emplaced turbulently. The Williams et al. (2005) model of thermal erosion by lava has been applied to what we term "proximal Athabasca," the 75 km long upstream portion of Athabasca Valles. For emplacement volumes of…
Spectral comparison and stability of red regions on Jupiter
Simon, Amy A.; Sanchez-Lavega, Agustin; Legarreta, Jon +4 more
A rare red cyclone visible on Jupiter in 1994 and 1995 falls in a class of vortices that are intensely colored, yet low altitude, unlike the Great Red Spot (GRS). Dynamical modeling indicates that the presence of nearby anticyclones both aids in formation and lead to the destruction of the cyclone. A study of absolute spectral reflectance from Hub…
Evolution of Mars' northern polar seasonal CO2 deposits: Variations in surface brightness and bulk density
Titus, Timothy N.; Mount, Christopher P.
Small-scale variations of seasonal ice are explored at different geomorphic units on the Northern Polar Seasonal Cap (NPSC). We use seasonal rock shadow measurements, combined with visible and thermal observations, to calculate density over time. The coupling of volume density and albedo allows us to determine the microphysical state of the season…
Hydraulic modeling of the tributary and the outlet of a Martian paleolake located in the Memnonia quadrangle
Pajola, M.; Baratti, E.; Rossato, S. +4 more
We present a steady state hydraulic model of the tributary and the outlet of a Martian paleolake located in the Memnonia quadrangle between 167°0'0''W and 167°30'0''W longitude and between 9°25'0''S and 9°45'0''S latitude. The Mars Express High-resolution stereo camera (HRSC) digital elevation model, H31850000DA4, with a spatial resolution of 75 m…
Relationship of dayside main layer ionosphere height to local solar time on Mars and implications for solar wind interaction influence
Huang, Qian; Zhang, Jie; Orosei, Roberto +1 more
To understand the influence of solar wind on the daytime main layer ionosphere of Mars, we investigated the local solar time (LST) variations of three characteristic heights of the ionosphere, namely, the heights of the 1 MHz and 1.5 MHz reflection points (i.e., 1.24 × 1010 m-3 and 2.79 × 1010 m-3 isoden…
Revised CRISM spectral parameters and summary products based on the currently detected mineral diversity on Mars
Viviano-Beck, Christina E.; Seelos, Frank P.; Murchie, Scott L. +8 more
The investigation of hyperspectral data from the Mars Reconnaissance Orbiter Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) and the Observatoire pour la Minéralogie, L'Eau, les Glaces et l'Activitié (OMEGA) on Mars Express has revealed an increasingly diverse suite of minerals present on the Martian surface. A revised set of 60 spect…
Global climate modeling of the Martian water cycle with improved microphysics and radiatively active water ice clouds
Forget, F.; Montmessin, F.; Millour, E. +4 more
Water ice clouds play a key role in the radiative transfer of the Martian atmosphere, impacting its thermal structure, its circulation, and, in turn, the water cycle. Recent studies including the radiative effects of clouds in global climate models (GCMs) have found that the corresponding feedbacks amplify the model defaults. In particular, it pre…
The origin and evolution of the Peace Vallis fan system that drains to the Curiosity landing area, Gale Crater, Mars
Williams, Rebecca M. E.; Palucis, Marisa C.; Calef, Fred +7 more
The landing site for the Curiosity rover is located at the distal end of the Peace Vallis fan in Gale Crater. Peace Vallis fan covers 80 km2 and is fed by a 730 km2 catchment, which drains an upland plains area through a 15 km wide gap in the crater rim. Valley incision into accumulated debris delivered sediment through a rel…
Atmosphere/mantle coupling and feedbacks on Venus
Gillmann, Cedric; Tackley, Paul
We investigate the coupled evolution of the atmosphere and mantle on Venus. Here we focus on mechanisms that deplete or replenish the atmosphere: atmospheric escape to space and volcanic degassing of the mantle. These processes are linked to obtain a coupled model of mantle convection and atmospheric evolution, including feedback of the atmosphere…