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@comment{{Command line: /usr/bin/bib2bib --quiet -c 'not journal:"Discussions"' -c year=2016 -c $type="ARTICLE" -oc pub2016.txt -ob pub2016.bib}}
  author = {{Bertrand}, T. and {Forget}, F.},
  title = {{Observed glacier and volatile distribution on Pluto from atmosphere-topography processes}},
  journal = {\nat},
  year = 2016,
  volume = 540,
  pages = {86-89},
  abstract = {{Pluto has a variety of surface frosts and landforms as well as a complex
atmosphere. There is ongoing geological activity related to the massive
Sputnik Planitia glacier, mostly made of nitrogen (N$_{2}$) ice
mixed with solid carbon monoxide and methane, covering the
4-kilometre-deep, 1,000-kilometre-wide basin of Sputnik Planitia near
the anti-Charon point. The glacier has been suggested to arise from a
source region connected to the deep interior, or from a sink collecting
the volatiles released planetwide. Thin deposits of N$_{2}$ frost,
however, were also detected at mid-northern latitudes and methane ice
was observed to cover most of Pluto except for the darker, frost-free
equatorial regions. Here we report numerical simulations of the
evolution of N$_{2}$, methane and carbon monoxide on Pluto over
thousands of years. The model predicts N$_{2}$ ice accumulation in
the deepest low-latitude basin and the threefold increase in atmospheric
pressure that has been observed to occur since 1988. This points to
atmospheric-topographic processes as the origin of Sputnik
Planitia{\rsquo}s N$_{2}$ glacier. The same simulations also
reproduce the observed quantities of volatiles in the atmosphere and
show frosts of methane, and sometimes N$_{2}$, that seasonally
cover the mid- and high latitudes, explaining the bright northern polar
cap reported in the 1990s and the observed ice distribution in 2015. The
model also predicts that most of these seasonal frosts should disappear
in the next decade.
  doi = {10.1038/nature19337},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Turbet}, M. and {Leconte}, J. and {Selsis}, F. and {Bolmont}, E. and 
	{Forget}, F. and {Ribas}, I. and {Raymond}, S.~N. and {Anglada-Escudé}, G.
  title = {{The habitability of Proxima Centauri b. II. Possible climates and observability}},
  journal = {\aap},
  archiveprefix = {arXiv},
  eprint = {1608.06827},
  primaryclass = {astro-ph.EP},
  keywords = {stars: individual: Proxima Cen, planets and satellites: individual: Proxima Cen b, planets and satellites: atmospheres, planets and satellites: terrestrial planets, planets and satellites: detection, astrobiology},
  year = 2016,
  volume = 596,
  eid = {A112},
  pages = {A112},
  abstract = {{Radial velocity monitoring has found the signature of a Msini =
1.3M$_{⊕}$ planet located within the habitable zone (HZ) of
Proxima Centauri. Despite a hotter past and an active host star, the
planet Proxima b could have retained enough volatiles to sustain surface
habitability. Here we use a 3D Global Climate Model (GCM) to simulate
the atmosphere and water cycle of Proxima b for its two likely rotation
modes (1:1 and 3:2 spin-orbit resonances), while varying the
unconstrained surface water inventory and atmospheric greenhouse effect.
Any low-obliquity, low-eccentricity planet within the HZ of its star
should be in one of the climate regimes discussed here. We find that a
broad range of atmospheric compositions allow surface liquid water. On a
tidally locked planet with sufficient surface water inventory, liquid
water is always present, at least in the substellar region. With a
non-synchronous rotation, this requires a minimum greenhouse warming (
10 mbar of CO$_{2}$ and 1 bar of N$_{2}$). If the planet is
dryer,  0.5 bar or 1.5 bars of CO$_{2}$ (for asynchronous or
synchronous rotation, respectively) suffice to prevent the trapping of
any arbitrary, small water inventory into polar or nightside ice caps.
We produce reflection and emission spectra and phase curves for the
simulated climates. We find that atmospheric characterization will be
possible via direct imaging with forthcoming large telescopes. The
angular separation of 7{$\lambda$}/D at 1 {$\mu$}m (with the E-ELT) and a
contrast of  10$^{-7}$ will enable high-resolution spectroscopy
and the search for molecular signatures, including H$_{2}$O,
O$_{2}$, and CO$_{2}$. The observation of thermal phase
curves can be attempted with the James Webb Space Telescope, thanks to a
contrast of 2 {\times} 10$^{-5}$ at 10 {$\mu$}m. Proxima b will also
be an exceptional target for future IR interferometers. Within a decade
it will be possible to image Proxima b and possibly determine whether
the surface of this exoplanet is habitable.
  doi = {10.1051/0004-6361/201629577},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Ribas}, I. and {Bolmont}, E. and {Selsis}, F. and {Reiners}, A. and 
	{Leconte}, J. and {Raymond}, S.~N. and {Engle}, S.~G. and {Guinan}, E.~F. and 
	{Morin}, J. and {Turbet}, M. and {Forget}, F. and {Anglada-Escudé}, G.
  title = {{The habitability of Proxima Centauri b. I. Irradiation, rotation and volatile inventory from formation to the present}},
  journal = {\aap},
  archiveprefix = {arXiv},
  eprint = {1608.06813},
  primaryclass = {astro-ph.EP},
  keywords = {stars: individual: Proxima Cen, planets and satellites: individual: Proxima b, planets and satellites: atmospheres, X-rays: stars, planet-star interactions},
  year = 2016,
  volume = 596,
  eid = {A111},
  pages = {A111},
  abstract = {{Proxima b is a planet with a minimum mass of 1.3M$_{⊕}$
orbiting within the habitable zone (HZ) of Proxima Centauri, a very
low-mass, active star and the Sun's closest neighbor. Here we
investigate a number of factors related to the potential habitability of
Proxima b and its ability to maintain liquid water on its surface. We
set the stage by estimating the current high-energy irradiance of the
planet and show that the planet currently receives 30 times more
extreme-UV radiation than Earth and 250 times more X-rays. We compute
the time evolution of the star's spectrum, which is essential for
modeling the flux received over Proxima b's lifetime. We also show that
Proxima b's obliquity is likely null and its spin is either synchronous
or in a 3:2 spin-orbit resonance, depending on the planet's eccentricity
and level of triaxiality. Next we consider the evolution of Proxima b's
water inventory. We use our spectral energy distribution to compute the
hydrogen loss from the planet with an improved energy-limited escape
formalism. Despite the high level of stellar activity we find that
Proxima b is likely to have lost less than an Earth ocean's worth of
hydrogen (EO$_{H}$) before it reached the HZ 100-200 Myr after its
formation. The largest uncertainty in our work is the initial water
budget, which is not constrained by planet formation models. We conclude
that Proxima b is a viable candidate habitable planet.
  doi = {10.1051/0004-6361/201629576},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Klose}, M. and {Jemmett-Smith}, B.~C. and {Kahanp{\"a}{\"a}}, H. and 
	{Kahre}, M. and {Knippertz}, P. and {Lemmon}, M.~T. and {Lewis}, S.~R. and 
	{Lorenz}, R.~D. and {Neakrase}, L.~D.~V. and {Newman}, C. and 
	{Patel}, M.~R. and {Reiss}, D. and {Spiga}, A. and {Whelley}, P.~L.
  title = {{Dust Devil Sediment Transport: From Lab to Field to Global Impact}},
  journal = {\ssr},
  keywords = {Dust devils, Dust emission, Lab experiments, Field measurements, Modeling, Dust environmental impact, Sediment transport, Earth, Mars, Planetary atmospheres},
  year = 2016,
  volume = 203,
  pages = {377-426},
  abstract = {{The impact of dust aerosols on the climate and environment of Earth and
Mars is complex and forms a major area of research. A difficulty arises
in estimating the contribution of small-scale dust devils to the total
dust aerosol. This difficulty is due to uncertainties in the amount of
dust lifted by individual dust devils, the frequency of dust devil
occurrence, and the lack of statistical generality of individual
experiments and observations. In this paper, we review results of
observational, laboratory, and modeling studies and provide an overview
of dust devil dust transport on various spatio-temporal scales as
obtained with the different research approaches. Methods used for the
investigation of dust devils on Earth and Mars vary. For example, while
the use of imagery for the investigation of dust devil occurrence
frequency is common practice for Mars, this is less so the case for
Earth. Modeling approaches for Earth and Mars are similar in that they
are based on the same underlying theory, but they are applied in
different ways. Insights into the benefits and limitations of each
approach suggest potential future research focuses, which can further
reduce the uncertainty associated with dust devil dust entrainment. The
potential impacts of dust devils on the climates of Earth and Mars are
discussed on the basis of the presented research results.
  doi = {10.1007/s11214-016-0261-4},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Spiga}, A. and {Barth}, E. and {Gu}, Z. and {Hoffmann}, F. and 
	{Ito}, J. and {Jemmett-Smith}, B. and {Klose}, M. and {Nishizawa}, S. and 
	{Raasch}, S. and {Rafkin}, S. and {Takemi}, T. and {Tyler}, D. and 
	{Wei}, W.},
  title = {{Large-Eddy Simulations of Dust Devils and Convective Vortices}},
  journal = {\ssr},
  keywords = {Dust devils, Large-Eddy Simulations, Convective vortices, Convective boundary layer},
  year = 2016,
  volume = 203,
  pages = {245-275},
  abstract = {{In this review, we address the use of numerical computations called
Large-Eddy Simulations (LES) to study dust devils, and the more general
class of atmospheric phenomena they belong to (convective vortices). We
describe the main elements of the LES methodology. We review the
properties, statistics, and variability of dust devils and convective
vortices resolved by LES in both terrestrial and Martian environments.
The current challenges faced by modelers using LES for dust devils are
also discussed in detail.
  doi = {10.1007/s11214-016-0284-x},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Lorenz}, R.~D. and {Balme}, M.~R. and {Gu}, Z. and {Kahanp{\"a}{\"a}}, H. and 
	{Klose}, M. and {Kurgansky}, M.~V. and {Patel}, M.~R. and {Reiss}, D. and 
	{Rossi}, A.~P. and {Spiga}, A. and {Takemi}, T. and {Wei}, W.
  title = {{History and Applications of Dust Devil Studies}},
  journal = {\ssr},
  year = 2016,
  volume = 203,
  pages = {5-37},
  abstract = {{Studies of dust devils, and their impact on society, are reviewed. Dust
devils have been noted since antiquity, and have been documented in many
countries, as well as on the planet Mars. As time-variable vortex
entities, they have become a cultural motif. Three major stimuli of dust
devil research are identified, nuclear testing, terrestrial climate
studies, and perhaps most significantly, Mars research. Dust devils
present an occasional safety hazard to light structures and have caused
several deaths.
  doi = {10.1007/s11214-016-0239-2},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Reiss}, D. and {Lorenz}, R.~D. and {Balme}, M. and {Neakrase}, L.~D. and 
	{Rossi}, A.~P. and {Spiga}, A. and {Zarnecki}, J.},
  title = {{Editorial: Topical Volume on Dust Devils}},
  journal = {\ssr},
  year = 2016,
  volume = 203,
  pages = {1-4},
  doi = {10.1007/s11214-016-0314-8},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Lebonnois}, S. and {Sugimoto}, N. and {Gilli}, G.},
  title = {{Wave analysis in the atmosphere of Venus below 100-km altitude, simulated by the LMD Venus GCM}},
  journal = {\icarus},
  keywords = {Venus, atmosphere, Atmospheres, dynamics, Numerical modeling},
  year = 2016,
  volume = 278,
  pages = {38-51},
  abstract = {{A new simulation of Venus atmospheric circulation obtained with the LMD
Venus GCM is described and the simulated wave activity is analyzed.
Agreement with observed features of the temperature structure, static
stability and zonal wind field is good, such as the presence of a cold
polar collar, diurnal and semi-diurnal tides. At the resolution used (96
longitudes {\times} 96 latitudes), a fully developed superrotation is
obtained both when the simulation is initialized from rest and from an
atmosphere already in superrotation, though winds are still weak below
the clouds (roughly half the observed values). The atmospheric waves
play a crucial role in the angular momentum budget of the Venus's
atmospheric circulation. In the upper cloud, the vertical angular
momentum is transported by the diurnal and semi-diurnal tides. Above the
cloud base (approximately 1 bar), equatorward transport of angular
momentum is done by polar barotropic and mid- to high-latitude
baroclinic waves present in the cloud region, with frequencies between 5
and 20 cycles per Venus day (periods between 6 and 23 Earth days). In
the middle cloud, just above the convective layer, a Kelvin type wave
(period around 7.3 Ed) is present at the equator, as well as a
low-latitude Rossby-gravity type wave (period around 16 Ed). Below the
clouds, large-scale mid- to high-latitude gravity waves develop and play
a significant role in the angular momentum balance.
  doi = {10.1016/j.icarus.2016.06.004},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Fouchet}, T. and {Greathouse}, T.~K. and {Spiga}, A. and {Fletcher}, L.~N. and 
	{Guerlet}, S. and {Leconte}, J. and {Orton}, G.~S.},
  title = {{Stratospheric aftermath of the 2010 Storm on Saturn as observed by the TEXES instrument. I. Temperature structure}},
  journal = {\icarus},
  archiveprefix = {arXiv},
  eprint = {1604.06479},
  primaryclass = {astro-ph.EP},
  keywords = {Saturn, atmosphere, Atmospheres, structure, Atmospheres, dynamics, Infrared observations},
  year = 2016,
  volume = 277,
  pages = {196-214},
  abstract = {{We report on spectroscopic observations of Saturn's stratosphere in July
2011 with the Texas Echelon Cross Echelle Spectrograph (TEXES) mounted
on the NASA InfraRed Telescope Facility (IRTF). The observations,
targeting several lines of the CH$_{4}${$\nu$}$_{4}$ band and
the H$_{2}$ S(1) quadrupolar line, were designed to determine how
Saturn's stratospheric thermal structure was disturbed by the 2010 Great
White Spot. A study of Cassini Composite Infrared Spectrometer (CIRS)
spectra had already shown the presence of a large stratospheric
disturbance centered at a pressure of 2 hPa, nicknamed the beacon B0,
and a tail of warm air at lower pressures (Fletcher et al. [2012] Icarus
221, 560-586). Our observations confirm that the beacon B0 vertical
structure determined by CIRS, with a maximum temperature of 180 {\plusmn}
1 K at 2 hPa, is overlain by a temperature decrease up to the 0.2-hPa
pressure level. Our retrieved maximum temperature of 180 {\plusmn} 1 K is
colder than that derived by CIRS (200 {\plusmn} 1 K), a difference that
may be quantitatively explained by terrestrial atmospheric smearing. We
propose a scenario for the formation of the beacon based on the
saturation of gravity waves emitted by the GWS. Our observations also
reveal that the tail is a planet-encircling disturbance in Saturn's
upper stratosphere, oscillating between 0.2 and 0.02 hPa, showing a
distinct wavenumber-2 pattern. We propose that this pattern in the upper
stratosphere is either the signature of thermal tides generated by the
presence of the warm beacon in the mid-stratosphere, or the signature of
Rossby wave activity.
  doi = {10.1016/j.icarus.2016.04.030},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Koskinen}, T.~T. and {Moses}, J.~I. and {West}, R.~A. and {Guerlet}, S. and 
	{Jouchoux}, A.},
  title = {{The detection of benzene in Saturn's upper atmosphere}},
  journal = {\grl},
  keywords = {Saturn, photochemistry},
  year = 2016,
  volume = 43,
  pages = {7895-7901},
  abstract = {{The stratosphere of Saturn contains a photochemical haze that appears
thicker at the poles and may originate from chemistry driven by the
aurora. Models suggest that the formation of hydrocarbon haze is
initiated at high altitudes by the production of benzene, which is
followed by the formation of heavier ring polycyclic aromatic
hydrocarbons. Until now there have been no observations of hydrocarbons
or photochemical haze in the production region to constrain these
models. We report the first vertical profiles of benzene and constraints
on haze opacity in the upper atmosphere of Saturn retrieved from Cassini
Ultraviolet Imaging Spectrograph stellar occultations. We detect benzene
at several different latitudes and find that the observed abundances of
benzene can be produced by solar-driven ion chemistry that is enhanced
at high latitudes in the northern hemisphere during spring. We also
detect evidence for condensation and haze at high southern latitudes in
the polar night.
  doi = {10.1002/2016GL070000},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Yang}, J. and {Leconte}, J. and {Wolf}, E.~T. and {Goldblatt}, C. and 
	{Feldl}, N. and {Merlis}, T. and {Wang}, Y. and {Koll}, D.~D.~B. and 
	{Ding}, F. and {Forget}, F. and {Abbot}, D.~S.},
  title = {{Differences in Water Vapor Radiative Transfer among 1D Models Can Significantly Affect the Inner Edge of the Habitable Zone}},
  journal = {\apj},
  archiveprefix = {arXiv},
  eprint = {1809.01397},
  primaryclass = {astro-ph.EP},
  keywords = {astrobiology, methods: numerical, planets and satellites: atmospheres, planets and satellites: general, planets and satellites: terrestrial planets, radiative transfer},
  year = 2016,
  volume = 826,
  eid = {222},
  pages = {222},
  abstract = {{An accurate estimate of the inner edge of the habitable zone is critical
for determining which exoplanets are potentially habitable and for
designing future telescopes to observe them. Here, we explore
differences in estimating the inner edge among seven one-dimensional
radiative transfer models: two line-by-line codes (SMART and LBLRTM) as
well as five band codes (CAM3, CAM4\_Wolf, LMDG, SBDART, and AM2) that
are currently being used in global climate models. We compare radiative
fluxes and spectra in clear-sky conditions around G and M stars, with
fixed moist adiabatic profiles for surface temperatures from 250 to 360
K. We find that divergences among the models arise mainly from large
uncertainties in water vapor absorption in the window region (10 {$\mu$}m)
and in the region between 0.2 and 1.5 {$\mu$}m. Differences in outgoing
longwave radiation increase with surface temperature and reach 10-20 W
m$^{-2}$ differences in shortwave reach up to 60 W m$^{-2}$,
especially at the surface and in the troposphere, and are larger for an
M-dwarf spectrum than a solar spectrum. Differences between the two
line-by-line models are significant, although smaller than among the
band models. Our results imply that the uncertainty in estimating the
insolation threshold of the inner edge (the runaway greenhouse limit)
due only to clear-sky radiative transfer is {\ap}10\% of modern
Earth{\rsquo}s solar constant (I.e., {\ap}34 W m$^{-2}$ in global
mean) among band models and {\ap}3\% between the two line-by-line models.
These comparisons show that future work is needed that focuses on
improving water vapor absorption coefficients in both shortwave and
longwave, as well as on increasing the resolution of stellar spectra in
broadband models.
  doi = {10.3847/0004-637X/826/2/222},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Modolo}, R. and {Hess}, S. and {Mancini}, M. and {Leblanc}, F. and 
	{Chaufray}, J.-Y. and {Brain}, D. and {Leclercq}, L. and {Esteban-Hern{\'a}ndez}, R. and 
	{Chanteur}, G. and {Weill}, P. and {Gonz{\'a}lez-Galindo}, F. and 
	{Forget}, F. and {Yagi}, M. and {Mazelle}, C.},
  title = {{Mars-solar wind interaction: LatHyS, an improved parallel 3-D multispecies hybrid model}},
  journal = {Journal of Geophysical Research (Space Physics)},
  keywords = {Mars, simulation, magnetosphere, plasma, interaction},
  year = 2016,
  volume = 121,
  pages = {6378-6399},
  abstract = {{In order to better represent Mars-solar wind interaction, we present an
unprecedented model achieving spatial resolution down to 50 km, a so far
unexplored resolution for global kinetic models of the Martian ionized
environment. Such resolution approaches the ionospheric plasma scale
height. In practice, the model is derived from a first version described
in Modolo et al. (2005). An important effort of parallelization has been
conducted and is presented here. A better description of the ionosphere
was also implemented including ionospheric chemistry, electrical
conductivities, and a drag force modeling the ion-neutral collisions in
the ionosphere. This new version of the code, named LatHyS (Latmos
Hybrid Simulation), is here used to characterize the impact of various
spatial resolutions on simulation results. In addition, and following a
global model challenge effort, we present the results of simulation run
for three cases which allow addressing the effect of the suprathermal
corona and of the solar EUV activity on the magnetospheric plasma
boundaries and on the global escape. Simulation results showed that
global patterns are relatively similar for the different spatial
resolution runs, but finest grid runs provide a better representation of
the ionosphere and display more details of the planetary plasma dynamic.
Simulation results suggest that a significant fraction of escaping
O$^{+}$ ions is originated from below 1200 km altitude.
  doi = {10.1002/2015JA022324},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Bertaux}, J.-L. and {Khatuntsev}, I.~V. and {Hauchecorne}, A. and 
	{Markiewicz}, W.~J. and {Marcq}, E. and {Lebonnois}, S. and 
	{Patsaeva}, M. and {Turin}, A. and {Fedorova}, A.},
  title = {{Influence of Venus topography on the zonal wind and UV albedo at cloud top level: The role of stationary gravity waves}},
  journal = {Journal of Geophysical Research (Planets)},
  keywords = {Venus, zonal wind, gravity waves, Venus Express, VMC, superrotation},
  year = 2016,
  volume = 121,
  pages = {1087-1101},
  abstract = {{Based on the analysis of UV images (at 365 nm) of Venus cloud top
(altitude 67 {\plusmn} 2 km) collected with Venus Monitoring Camera on
board Venus Express (VEX), it is found that the zonal wind speed south
of the equator (from 5{\deg}S to 15{\deg}S) shows a conspicuous variation
(from -101 to -83 m/s) with geographic longitude of Venus, correlated
with the underlying relief of Aphrodite Terra. We interpret this pattern
as the result of stationary gravity waves produced at ground level by
the uplift of air when the horizontal wind encounters a mountain slope.
These waves can propagate up to the cloud top level, break there, and
transfer their momentum to the zonal flow. Such upward propagation of
gravity waves and influence on the wind speed vertical profile was shown
to play an important role in the middle atmosphere of the Earth by
Lindzen (1981) but is not reproduced in the current GCM of Venus
atmosphere from LMD. (Laboratoire de Météorologie
Dynamique) In the equatorial regions, the UV albedo at 365 nm varies
also with longitude. We argue that this variation may be simply
explained by the divergence of the horizontal wind field. In the
longitude region (from 60{\deg} to -10{\deg}) where the horizontal wind
speed is increasing in magnitude (stretch), it triggers air upwelling
which brings the UV absorber at cloud top level and decreases the albedo
and vice versa when the wind is decreasing in magnitude (compression).
This picture is fully consistent with the classical view of Venus
meridional circulation, with upwelling at equator revealed by horizontal
air motions away from equator: the longitude effect is only an
additional but important modulation of this effect. This interpretation
is comforted by a recent map of cloud top H$_{2}$O, showing that
near the equator the lower UV albedo longitude region is correlated with
increased H$_{2}$O. We argue that H$_{2}$O enhancement is
the sign of upwelling, suggesting that the UV absorber is also brought
to cloud top by upwelling.
  doi = {10.1002/2015JE004958},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Piccialli}, A. and {L{\'o}pez-Valverde}, M.~A. and {M{\"a}{\"a}tt{\"a}nen}, A. and 
	{Gonz{\'a}lez-Galindo}, F. and {Audouard}, J. and {Altieri}, F. and 
	{Forget}, F. and {Drossart}, P. and {Gondet}, B. and {Bibring}, J.~P.
  title = {{CO$_{2}$ non-LTE limb emissions in Mars' atmosphere as observed by OMEGA/Mars Express}},
  journal = {Journal of Geophysical Research (Planets)},
  keywords = {planetary atmospheres, Mars atmosphere, non-LTE emissions, remote sensing, infrared observations},
  year = 2016,
  volume = 121,
  pages = {1066-1086},
  abstract = {{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 {$\mu$}m is interpreted as due to
CO$_{2}$ fluorescence of solar radiation and is detected at a
tangent altitude in between 60 and 110 km. The main value of OMEGA
observations is that they provide simultaneously spectral information
and good spatial sampling of the CO$_{2}$ emission. In this study
we analyzed 98 dayside limb observations spanning over more than 3
Martian years, with a very good latitudinal and longitudinal coverage.
Thanks to the precise altitude sounding capabilities of OMEGA, we
extracted vertical profiles of the non-local thermodynamic equilibrium
(non-LTE) emission at each wavelength and we studied their dependence on
several geophysical parameters, such as the solar illumination and the
tangent altitude. The dependence of the non-LTE emission on solar zenith
angle and altitude follows a similar behavior to that predicted by the
non-LTE model. According to our non-LTE model, the tangent altitude of
the peak of the CO$_{2}$ emission varies with the thermal
structure, but the pressure level where the peak of the emission is
found remains constant at {\tilde}0.03 {\plusmn} 0.01 Pa, . This non-LTE
model prediction has been corroborated by comparing SPICAM and OMEGA
observations. We have shown that the seasonal variations of the altitude
of constant pressure levels in SPICAM stellar occultation retrievals
correlate well with the variations of the OMEGA peak emission altitudes,
although the exact pressure level cannot be defined with the
spectroscopy for the investigation of the characteristics of the
atmosphere of Venus (SPICAM) nighttime data. Thus, observed changes in
the altitude of the peak emission provide us information on the altitude
of the 0.03 Pa pressure level. Since the pressure at a given altitude is
dictated by the thermal structure below, the tangent altitude of the
peak emission represents then an important piece of information of the
atmosphere, of great value for validating general circulation models. We
thus compared the altitude of OMEGA peak emission with the altitude of
the 0.03 Pa level predicted by the Laboratoire de
météorologie dynamique (LMD)-Mars global circulation model
and found that the peak emission altitudes from OMEGA present a much
larger variability than the tangent altitude of the 0.03 Pa level
predicted by the general circulation model. This variability could be
possibly due to unresolved atmospheric waves. Further studies using this
strong CO$_{2}$ limb emission data are proposed.
  doi = {10.1002/2015JE004981},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Bouley}, S. and {Baratoux}, D. and {Matsuyama}, I. and {Forget}, F. and 
	{Séjourné}, A. and {Turbet}, M. and {Costard}, F.},
  title = {{Late Tharsis formation and implications for early Mars}},
  journal = {\nat},
  year = 2016,
  volume = 531,
  pages = {344-347},
  abstract = {{The Tharsis region is the largest volcanic complex on Mars and in the
Solar System. Young lava flows cover its surface (from the Amazonian
period, less than 3 billion years ago) but its growth started during the
Noachian era (more than 3.7 billion years ago). Its position has induced
a reorientation of the planet with respect to its spin axis (true polar
wander, TPW), which is responsible for the present equatorial position
of the volcanic province. It has been suggested that the Tharsis load on
the lithosphere influenced the orientation of the Noachian/Early
Hesperian (more than 3.5 billion years ago) valley networks and
therefore that most of the topography of Tharsis was completed before
fluvial incision. Here we calculate the rotational figure of Mars (that
is, its equilibrium shape) and its surface topography before Tharsis
formed, when the spin axis of the planet was controlled by the
difference in elevation between the northern and southern hemispheres
(hemispheric dichotomy). We show that the observed directions of valley
networks are also consistent with topographic gradients in this
configuration and thus do not require the presence of the Tharsis load.
Furthermore, the distribution of the valleys along a small circle tilted
with respect to the equator is found to correspond to a
southern-hemisphere latitudinal band in the pre-TPW geographical frame.
Preferential accumulation of ice or water in a south tropical band is
predicted by climate model simulations of early Mars applied to the
pre-TPW topography. A late growth of Tharsis, contemporaneous with
valley incision, has several implications for the early geological
history of Mars, including the existence of glacial environments near
the locations of the pre-TPW poles of rotation, and a possible link
between volcanic outgassing from Tharsis and the stability of liquid
water at the surface of Mars.
  doi = {10.1038/nature17171},
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  author = {{Encrenaz}, T. and {DeWitt}, C. and {Richter}, M.~J. and {Greathouse}, T.~K. and 
	{Fouchet}, T. and {Montmessin}, F. and {Lefèvre}, F. and 
	{Forget}, F. and {Bézard}, B. and {Atreya}, S.~K. and {Case}, M. and 
	{Ryde}, N.},
  title = {{A map of D/H on Mars in the thermal infrared using EXES aboard SOFIA}},
  journal = {\aap},
  keywords = {planets and satellites: atmospheres, planets and satellites: composition, planets and satellites: terrestrial planets, infrared: planetary systems},
  year = 2016,
  volume = 586,
  eid = {A62},
  pages = {A62},
  abstract = {{On a planetary scale, the D/H ratio on Mars is a key diagnostic for
understanding the past history of water on the planet; locally, it can
help to constrain the sources and sinks of water vapor through the
monitoring of condensation and sublimation processes. To obtain
simultaneous measurements of H$_{2}$O and HDO lines, we have used
the Echelle Cross Echelle Spectrograph (EXES) instrument aboard the
Stratospheric Observatory for Infrared Astronomy (SOFIA) facility to map
the abundances of these two species over the Martian disk.
High-resolution spectra (R = 6 {\times} 10$^{4}$) were recorded in
the 1383-1390 cm$^{-1}$ range (7.2 {$\mu$}m) on April 08, 2014. Mars
was very close to opposition and near northern summer solstice (Ls =
113{\deg}). Maps of the H$_{2}$O and HDO mixing ratios were
retrieved from the line depth ratios of weak H$_{2}$O and HDO
transitions divided by a weak CO$_{2}$ line. As expected for this
season, the H$_{2}$O and HDO maps show a distinct enhancement
toward polar regions, and their mixing ratios are consistent with
previous measurements and with predictions by the global climate models,
except at the north pole where the EXES values are weaker. We derive a
disk-integrated D/H ratio of 6.8 (+1.6, -1.0) {\times} 10$^{-4}$.
It is higher than the value in Earth's oceans by a factor 4.4 (+1.0,
-0.6). The D/H map also shows an enhancement from southern to northern
latitudes, with values ranging from about 3.5 times to 6.0 times the
VSMOW (Vienna standard mean ocean water) value. The D/H distribution
shows a depletion over the Tharsis mountains and is consistent with
observed latitudinal variations. The variations in D/H with latitude and
altitude agree with the models and with the isotope fractionation
expected from condensation and sublimation processes.
  doi = {10.1051/0004-6361/201527018},
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  author = {{Read}, P.~L. and {Barstow}, J. and {Charnay}, B. and {Chelvaniththilan}, S. and 
	{Irwin}, P.~G.~J. and {Knight}, S. and {Lebonnois}, S. and {Lewis}, S.~R. and 
	{Mendon{\c c}a}, J. and {Montabone}, L.},
  title = {{Global energy budgets and `Trenberth diagrams' for the climates of terrestrial and gas giant planets}},
  journal = {Quarterly Journal of the Royal Meteorological Society},
  year = 2016,
  volume = 142,
  pages = {703-720},
  doi = {10.1002/qj.2704},
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  author = {{Pilorget}, C. and {Forget}, F.},
  title = {{Formation of gullies on Mars by debris flows triggered by CO$_{2}$ sublimation}},
  journal = {Nature Geoscience},
  year = 2016,
  volume = 9,
  pages = {65-69},
  abstract = {{Martian gully landforms resemble terrestrial debris flows formed by the
action of liquid water and have thus been interpreted as evidence for
potential habitable environments on Mars within the past few millennia.
However, ongoing gully formation has been detected under surface
conditions much too cold for liquid water, but at times in the martian
year when a thin layer of seasonal CO$_{2}$ frost is present and
defrosting above the regolith. These observations suggest that the
CO$_{2}$ condensation-sublimation cycle could play a role in gully
formation. Here we use a thermo-physical numerical model of the martian
regolith underlying a CO$_{2}$ ice layer and atmosphere to show
that the pores beneath the ice layer can be filled with CO$_{2}$
ice and subjected to extreme pressure variations during the defrosting
season. The subsequent gas fluxes can destabilize the regolith material
and induce gas-lubricated debris flows with geomorphic characteristics
similar to martian gullies. Moreover, we find that subsurface
CO$_{2}$ ice condensation, sublimation and pressurization occurs
at conditions found at latitudes and slope orientations where gullies
are observed. We conclude that martian gullies can result from geologic
dry ice processes that have no terrestrial analogues and do not require
liquid water. Such dry ice processes may have helped shape the evolution
of landforms elsewhere on the martian surface.
  doi = {10.1038/ngeo2619},
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  author = {{Mulholland}, D.~P. and {Lewis}, S.~R. and {Read}, P.~L. and 
	{Madeleine}, J.-B. and {Forget}, F.},
  title = {{The solsticial pause on Mars: 2 modelling and investigation of causes}},
  journal = {\icarus},
  keywords = {Mars, atmosphere, climate, Atmospheres, dynamics},
  year = 2016,
  volume = 264,
  pages = {465-477},
  abstract = {{The martian solsticial pause, presented in a companion paper (Lewis et
al., 2016), was investigated further through a series of model runs
using the UK version of the LMD/UK Mars Global Climate Model. It was
found that the pause could not be adequately reproduced if radiatively
active water ice clouds were omitted from the model. When clouds were
used, along with a realistic time-dependent dust opacity distribution, a
substantial minimum in near-surface transient eddy activity formed
around solstice in both hemispheres. The net effect of the clouds in the
model is, by altering the thermal structure of the atmosphere, to
decrease the vertical shear of the westerly jet near the surface around
solstice, and thus reduce baroclinic growth rates. A similar effect was
seen under conditions of large dust loading, implying that northern
midlatitude eddy activity will tend to become suppressed after a period
of intense flushing storm formation around the northern cap edge.
Suppression of baroclinic eddy generation by the barotropic component of
the flow and via diabatic eddy dissipation were also investigated as
possible mechanisms leading to the formation of the solsticial pause but
were found not to make major contributions. Zonal variations in
topography were found to be important, as their presence results in
weakened transient eddies around winter solstice in both hemispheres,
through modification of the near-surface flow. The zonal topographic
asymmetry appears to be the primary reason for the weakness of eddy
activity in the southern hemisphere relative to the northern hemisphere,
and the ultimate cause of the solsticial pause in both hemispheres. The
meridional topographic gradient was found to exert a much weaker
influence on near-surface transient eddies.
  doi = {10.1016/j.icarus.2015.08.038},
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