Search Publications
Shallow water simulations of Saturn's giant storms at different latitudes
Sánchez-Lavega, A.; García-Melendo, E.
Shallow water simulations are used to present a unified study of three major storms on Saturn (nicknamed as Great White Spots, GWS) at different latitudes, polar (1960), equatorial (1990), and mid-latitude (2010) (Sánchez-Lavega, 2004; Sánchez-Lavega et al., 2011). In our model, the three GWS are initiated by introducing a Gaussian function pulse …
Aerosols optical properties in Titan's detached haze layer before the equinox
West, Robert A.; Seignovert, Benoît; Lavvas, Panayotis +2 more
UV observations with Cassini ISS Narrow Angle Camera of Titan's detached haze is an excellent tool to probe its aerosols content without being affected by the gas or the multiple scattering. Unfortunately, its low extent in altitude requires a high resolution calibration and limits the number of images available in the Cassini dataset. However, we…
The role of strength defects in shaping impact crater planforms
Watters, W. A.; Geiger, L. M.; Fendrock, M. +2 more
High-resolution imagery and digital elevation models (DEMs) were used to measure the planimetric shapes of well-preserved impact craters. These measurements were used to characterize the size-dependent scaling of the departure from circular symmetry, which provides useful insights into the processes of crater growth and modification. For example, …
Temperatures and CH4 mixing ratios near the homopause of the 8 µm north polar hot spot of Jupiter
Orton, G. S.; Kim, Sang Joon; Yung, Yuk L. +4 more
We have derived homopause temperatures of 180-250 K for the 8-µm north-polar hot spot (8NPHS) of Jupiter by fitting CH4 emission models to 3 and 8 µm spectra of the 8NPHS obtained 24 days apart in 2013. From the fits, we find that CH4 mixing ratios at the 8NPHS are consistent with those reported by Kim et al. (201…
Modelled isotopic fractionation and transient diffusive release of methane from potential subsurface sources on Mars
Stevens, Adam H.; Lewis, Stephen R.; Patel, Manish R.
We calculate transport timescales of martian methane and investigate the effect of potential release mechanisms into the atmosphere using a numerical model that includes both Fickian and Knudsen diffusion. The incorporation of Knudsen diffusion, which improves on a Fickian description of transport given the low permeability of the martian regolith…
The photochemical fractionation of oxygen isotopologues in Titan's atmosphere
Dobrijevic, M.; Loison, J. C.; Hickson, K. M. +1 more
The origin of CO and the external source of H2O in the atmosphere of Titan is still a matter of debate. We investigated the chemical fractionation of oxygen isotopologues in order to give new constraints on the origin of oxygen species. We created a new chemical scheme and we developed a 1-D time-dependent photochemical model to compute…
The effect of like-charge attraction on aerosol growth in the atmosphere of Titan
Lindgren, Eric B.; Stamm, Benjamin; Chan, Ho-Kei +3 more
The formation of aerosols in the atmosphere of Titan is based extensively on ion-neutral chemistry and physical condensation processes. Herein it is shown that the formation of aerosols may also occur through an alternative pathway that involves the physical aggregation of negatively charged particles, which are known to be abundant in the satelli…
Dawn-dusk difference of periodic oxygen EUV dayglow variations at Venus observed by Hisaki
Leblanc, François; Tsuchiya, Fuminori; Seki, Kanako +8 more
We report a dawn-dusk difference of periodic variations of oxygen EUV dayglow (OII 83.4 nm, OI 130.4 nm and OI 135.6 nm) in the upper atmosphere of Venus observed by the Hisaki spacecraft in 2015. Observations show that the periodic dayglow variations are mainly controlled by the solar EUV flux. Additionally, we observed characteristic ∼1 day and …
Radiative energy balance of Venus: An approach to parameterize thermal cooling and solar heating rates
Kappel, D.; Arnold, G.; Haus, R.
Thermal cooling rates QC and solar heating rates QH in the atmosphere of Venus at altitudes between 0 and 100 km are investigated using the radiative transfer and radiative balance simulation techniques described by Haus et al. (2015b, 2016). QC strongly responds to temperature profile and cloud parameter changes, …
Diurnal observations of HCl altitude variation in the 70-100 km mesosphere of Venus
Todd Clancy, R.; Sandor, Brad J.
First submm spectroscopic observations of the 625.9 GHz H35Cl absorption lines of the Venus dayside atmosphere were obtained with the James Clerk Maxwell Telescope (JCMT) on March 2, 2013. These data, which support retrieval of HCl altitude distributions in the Venus mesosphere (70-100 km), are presented here and compared with previousl…