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We have developed a seasonal radiative–dynamical model of Titan's stratosphere to investigate the temporal variation of temperatures in the 0.2–4 mbar range observed by the Cassini/CIRS spectrometer. The model incorporates gas and aerosol vertical profiles derived from Cassini/CIRS and Huygens/DISR data to calculate the radiative heating and cooling rate profiles as a function of time and latitude...
The temperature of the night side of Venus at about 95 km has been determined by using spectral features of the hydroxyl airglow emission around 3 µm, recorded from July 2006 to July 2008 by VIRTIS onboard Venus Express. The retrieved temperatures vary from 145.5 to about 198.1 K with an average value of 176.3 ± 14.3 K and are in good agreement with previous ground-based and space observations. The...
The Alice instrument on NASA's New Horizons spacecraft observed an ultraviolet solar occultation by Pluto's atmosphere on 2015 July 14. The transmission vs. altitude was sensitive to the presence of N2, CH4, C2H2, C2H4, C2H6, and haze. We derived line-of-sight abundances and local number densities for the 5 molecular species, and line-of-sight optical depth and extinction coefficients for the haze...
From the angular positions of the glory features observed on the upper cloud deck of Venus in three VMC channels (at 0.365, 0.513, and 0.965 µm), the dominating sizes of cloud particles and their refractive indices have been retrieved, and their spatial and temporal variations have been analyzed. For this, the phase profiles of brightness were compared to the single-scattering phase functions of particles...
On 14 July 2015 New Horizons performed a radio occultation (RO) that sounded Pluto’s atmosphere down to the surface. The sensitivity of the measurements was enhanced by a unique configuration of ground equipment and spacecraft instrumentation. Signals were transmitted simultaneously by four antennas of the NASA Deep Space Network, each radiating 20 kW at a wavelength of 4.2 cm. The polarization was...
Jupiter’s tropospheric composition is studied using high-resolution, spatially-resolved 5-µm observations from the CRIRES instrument at the Very Large Telescope. The high resolving power (R = 96,000) allows us to spectrally resolve the line shapes of individual molecular species in Jupiter’s troposphere and, by aligning the slit north-south along Jupiter’s central meridian, we are able to search for...
We apply the direct simulation Monte Carlo rarefied gas dynamic technique to simulations of Pluto's rarefied upper atmosphere motivated by the need to better understand New Horizons (NH) data. We present a novel three-dimensional DSMC model of the atmosphere that spans from several hundred km below the exobase – where continuum flow transitions to the rarefied regime – to fully free-molecular flow...
We retrieve vertical and meridional variations of methane mole fraction in Titan’s lower troposphere by re-analyzing near-infrared ground-based observations from 17 July 2014 UT (Ádámkovics et al., 2016). We generate synthetic spectra using atmospheric methane profiles that do not contain supersaturation or discontinuities to fit the observations, and thereby retrieve minimum saturation altitudes...
Thermal cooling rates QC and solar heating rates QH in the atmosphere of Venus at altitudes between 0 and 100km 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, while QH is less sensitive to these parameters. The latter mainly depends on solar insolation...
Air temperature, ground temperature, pressure, and wind speed and direction data obtained from the Rover Environmental Monitoring Station onboard the Mars Science Laboratory rover Curiosity are compared to data from the Mars Regional Atmospheric Modeling System. A full diurnal cycle at four different seasons (Ls 0, 90, 180 and 270) is investigated at the rover location within Gale crater, Mars. Model...
Numerical modeling results from the Mars Regional Atmospheric Modeling System are used to interpret the landed meteorological data from the Rover Environmental Monitoring Station onboard the Mars Science Laboratory rover Curiosity. In order to characterize seasonal changes throughout the Martian year, simulations are conducted at Ls 0, 90, 180 and 270. Two additional simulations at Ls 225 and 315...
We studied the evolution of a giant tropospheric vortex formed in the wake of the storm that encircled Saturn from December 2010 to July 2011 (Fletcher et al. [2011a] Science, 332, 1413–1417; Fletcher et al. [2012] Icarus, 221, 560–586; Sánchez-Lavega et al. [2011] Nature, 475, 71–74; Sánchez-Lavega et al. [2012] Icarus, 220, 561–576; Sayanagi et al. [2013] Icarus, 223, 460–478; Fischer et al. [2011]...
SPICAV IR, a channel of the SPICAV/SOIR suite of instruments onboard Venus Express spacecraft measured spectra in nadir and solar occultation modes in the range of 0.65–1.7μm. We report results from 222 solar occultations observed from May 2006 to November 2014. The vertical resolution of measurements varies from 1 to 25km depending on the distance of the spacecraft to the limb of Venus. The vertical...
We search for meridional variation in the abundance of CH3D relative to CH4 on Titan using near-IR spectra obtained with NIRSPAO at Keck, which have a photon-limited signal-to-noise ratio of ∼50. Our observations can rule out a larger than 10% variation in the column of CH3D below 50 km. The preferential condensation of the heavy isotopologues will fractionate methane by reducing CH3D in the remaining...
The distribution of sources and sinks of radiative energy forces the atmospheric dynamics. The radiative transfer simulation model described by Haus et al. (2015b) is applied to calculate fluxes and temperature change rates in the middle and lower atmosphere of Venus (0–100km) covering the energetic significant spectral range 0.125–1000µm. The calculations rely on improved models of atmospheric parameters...
Chamberlain ([1963] Planet. Space Sci., 11, 901–960) described the use of the exobase layer to determine escape from planetary atmospheres, below which it is assumed that molecular collisions maintain thermal equilibrium and above which collisions are deemed negligible. De La Haye et al. ([2007] Icarus., 191, 236–250) used this approximation to extract the energy deposition and non-thermal escape...
New observations of Neptune’s clouds in the near infrared were acquired in October 2013 with SINFONI on ESO’s Very Large Telescope (VLT) in Chile. SINFONI is an Integral Field Unit spectrometer returning a 64 × 64 pixel image with 2048 wavelengths. Image cubes in the J-band (1.09–1.41 µm) and H-band (1.43–1.87 µm) were obtained at spatial resolutions of 0.1″and 0.025″per pixel, while SINFONI’s adaptive...
The spatial distribution of the tropospheric methane on Titan was measured using near-infrared spectroscopy. Ground-based observations at 1.5μm (H-band) were performed during the same night using instruments with adaptive optics at both the W.M. Keck Observatory and at the Paranal Observatory on 17 July 2014 UT. The integral field observations with SINFONI on the VLT covered the entire H-band at moderate...
The Space Telescope Imaging Spectrograph accumulated image cubes of Titan in five years between 1997 and 2004 that we calibrated and analyzed. The observations probe Titan’s early northern fall to early winter. Methane bands between 543 and 990nm wavelength are well resolved spectrally, and Titan’s latitudinal and center-to-limb reflectivity variations are resolved spatially. A principal component...
We analyze spectra acquired by the Cassini/Composite Infrared Spectrometer (CIRS) at high resolution from October 2010 until September 2014 in nadir mode. Up until mid 2012, Titan’s Northern atmosphere exhibited the enriched chemical content found since the Voyager days (November 1980), with a peak around the Northern Spring Equinox (NSE) in 2009. Since then, we have observed the appearance at Titan’s...
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