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@comment{{Command line: /usr/bin/bib2bib --quiet -c 'not journal:"Discussions"' -c year=2017 -c $type="ARTICLE" -oc pub2017.txt -ob pub2017.bib}}
  author = {{Limaye}, S.~S. and {Lebonnois}, S. and {Mahieux}, A. and {P{\"a}tzold}, M. and 
	{Bougher}, S. and {Bruinsma}, S. and {Chamberlain}, S. and {Clancy}, R.~T. and 
	{Gérard}, J.-C. and {Gilli}, G. and {Grassi}, D. and {Haus}, R. and 
	{Herrmann}, M. and {Imamura}, T. and {Kohler}, E. and {Krause}, P. and 
	{Migliorini}, A. and {Montmessin}, F. and {Pere}, C. and {Persson}, M. and 
	{Piccialli}, A. and {Rengel}, M. and {Rodin}, A. and {Sandor}, B. and 
	{Sornig}, M. and {Svedhem}, H. and {Tellmann}, S. and {Tanga}, P. and 
	{Vandaele}, A.~C. and {Widemann}, T. and {Wilson}, C.~F. and 
	{M{\"u}ller-Wodarg}, I. and {Zasova}, L.},
  title = {{The thermal structure of the Venus atmosphere: Intercomparison of Venus Express and ground based observations of vertical temperature and density profiles$^{✰}$}},
  journal = {\icarus},
  year = 2017,
  volume = 294,
  pages = {124-155},
  abstract = {{The Venus International Reference Atmosphere (VIRA) model contains
tabulated values of temperature and number densities obtained by the
experiments on the Venera entry probes, Pioneer Venus Orbiter and
multi-probe missions in the 1980s. The instruments on the recent Venus
Express orbiter mission generated a significant amount of new
observational data on the vertical and horizontal structure of the Venus
atmosphere from 40 km to about 180 km altitude from April 2006 to
November 2014. Many ground based experiments have provided data on the
upper atmosphere (90-130 km) temperature structure since the publication
of VIRA in 1985. The ``Thermal Structure of the Venus Atmosphere'' Team
was supported by the International Space Studies Institute (ISSI), Bern,
Switzerland, from 2013 to 2015 in order to combine and compare the
ground-based observations and the VEx observations of the thermal
structure as a first step towards generating an updated VIRA model.
Results of this comparison are presented in five latitude bins and three
local time bins by assuming hemispheric symmetry. The intercomparison of
the ground-based and VEx results provides for the first time a
consistent picture of the temperature and density structure in the 40
km-180 km altitude range. The Venus Express observations have
considerably increased our knowledge of the Venus atmospheric thermal
structure above {\sim}40 km and provided new information above 100 km.
There are, however, still observational gaps in latitude and local time
above certain regions. Considerable variability in the temperatures and
densities is seen above 100 km but certain features appear to be
systematically present, such as a succession of warm and cool layers.
Preliminary modeling studies support the existence of such layers in
agreement with a global scale circulation. The intercomparison focuses
on average profiles but some VEx experiments provide sufficient global
coverage to identify solar thermal tidal components.

The differences between the VEx temperature profiles and the VIRA below
0.1 mbar/95 km are small. There is, however, a clear discrepancy at high
latitudes in the 10-30 mbar (70-80 km) range. The VEx observations will
also allow the improvement of the empirical models (VTS3 by Hedin et
al., 1983 and VIRA by Keating et al., 1985) above 0.03 mbar/100 km, in
particular the 100-150 km region where a sufficient observational
coverage was previously missing. The next steps in order to define the
updated VIRA temperature structure up to 150 km altitude are (1) define
the grid on which this database may be provided, (2) fill what is
possible with the results of the data intercomparison, and (3) fill the
observational gaps. An interpolation between the datasets may be
performed by using available General Circulation Models as guidelines.

An improved spatial coverage of observations is still necessary at all
altitudes, in latitude-longitude and at all local solar times for a
complete description of the atmospheric thermal structure, in particular
on the dayside above 100 km. New in-situ observations in the atmosphere
below 40 km are missing, an altitude region that cannot be accessed by
occultation experiments. All these questions need to be addressed by
future missions.
  doi = {10.1016/j.icarus.2017.04.020},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Pottier}, A. and {Forget}, F. and {Montmessin}, F. and {Navarro}, T. and 
	{Spiga}, A. and {Millour}, E. and {Szantai}, A. and {Madeleine}, J.-B.
  title = {{Unraveling the martian water cycle with high-resolution global climate simulations}},
  journal = {\icarus},
  keywords = {Mars atmosphere, Atmospheres dynamics, Mars, Climate, Meteorology},
  year = 2017,
  volume = 291,
  pages = {82-106},
  abstract = {{Global climate modeling of the Mars water cycle is usually performed at
relatively coarse resolution (200 - 300km), which may not be sufficient
to properly represent the impact of waves, fronts, topography effects on
the detailed structure of clouds and surface ice deposits. Here, we
present new numerical simulations of the annual water cycle performed at
a resolution of 1{\deg} {\times} 1{\deg} ({\sim} 60 km in latitude). The
model includes the radiative effects of clouds, whose influence on the
thermal structure and atmospheric dynamics is significant, thus we also
examine simulations with inactive clouds to distinguish the direct
impact of resolution on circulation and winds from the indirect impact
of resolution via water ice clouds. To first order, we find that the
high resolution does not dramatically change the behavior of the system,
and that simulations performed at {\sim} 200 km resolution capture well
the behavior of the simulated water cycle and Mars climate.
Nevertheless, a detailed comparison between high and low resolution
simulations, with reference to observations, reveal several significant
changes that impact our understanding of the water cycle active today on
Mars. The key northern cap edge dynamics are affected by an increase in
baroclinic wave strength, with a complication of northern summer
dynamics. South polar frost deposition is modified, with a westward
longitudinal shift, since southern dynamics are also influenced.
Baroclinic wave mode transitions are observed. New transient phenomena
appear, like spiral and streak clouds, already documented in the
observations. Atmospheric circulation cells in the polar region exhibit
a large variability and are fine structured, with slope winds. Most
modeled phenomena affected by high resolution give a picture of a more
turbulent planet, inducing further variability. This is challenging for
long-period climate studies.
  doi = {10.1016/j.icarus.2017.02.016},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Kenda}, B. and {Lognonné}, P. and {Spiga}, A. and {Kawamura}, T. and 
	{Kedar}, S. and {Banerdt}, W.~B. and {Lorenz}, R. and {Banfield}, D. and 
	{Golombek}, M.},
  title = {{Modeling of Ground Deformation and Shallow Surface Waves Generated by Martian Dust Devils and Perspectives for Near-Surface Structure Inversion}},
  journal = {\ssr},
  keywords = {Dust devils, Mars, Ground tilt, Subsurface, Large-eddy simulation, Insight},
  year = 2017,
  abstract = {{We investigated the possible seismic signatures of dust devils on Mars,
both at long and short period, based on the analysis of Earth data and
on forward modeling for Mars. Seismic and meteorological data collected
in the Mojave Desert, California, recorded the signals generated by dust
devils. In the 10-100 s band, the quasi-static surface deformation
triggered by pressure fluctuations resulted in detectable ground-tilt
effects: these are in good agreement with our modeling based on
Sorrells' theory. In addition, high-frequency records also exhibit a
significant excitation in correspondence to dust devil episodes. Besides
wind noise, this signal includes shallow surface waves due to the
atmosphere-surface coupling and is used for a preliminary inversion of
the near-surface S-wave profile down to 50 m depth. In the case of Mars,
we modeled the long-period signals generated by the pressure field
resulting from turbulence-resolving Large-Eddy Simulations. For typical
dust-devil-like vortices with pressure drops of a couple Pascals, the
corresponding horizontal acceleration is of a few nm/s$^{2}$ for
rocky subsurface models and reaches 10-20 nm/s$^{2}$ for weak
regolith models. In both cases, this signal can be detected by the
Very-Broad Band seismometers of the InSight/SEIS experiment up to a
distance of a few hundred meters from the vortex, the amplitude of the
signal decreasing as the inverse of the distance. Atmospheric vortices
are thus expected to be detected at the InSight landing site; the
analysis of their seismic and atmospheric signals could lead to
additional constraints on the near-surface structure, more precisely on
the ground compliance and possibly on the seismic velocities.
  doi = {10.1007/s11214-017-0378-0},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Steele}, L.~J. and {Balme}, M.~R. and {Lewis}, S.~R. and {Spiga}, A.
  title = {{The water cycle and regolith-atmosphere interaction at Gale crater, Mars}},
  journal = {\icarus},
  keywords = {Mars, atmosphere, climate, surface},
  year = 2017,
  volume = 289,
  pages = {56-79},
  abstract = {{We perform mesoscale simulations of the water cycle in a region around
Gale crater, including the diffusion of water vapour in and out of the
regolith, and compare our results with measurements from the REMS
instrument on board the Curiosity rover. Simulations are performed at
three times of year, and show that diffusion in and out of the regolith
and adsorption/desorption needs to be taken into account in order to
match the diurnal variation of relative humidity measured by REMS.
During the evening and night, local downslope flows transport water
vapour down the walls of Gale crater. When including regolith-atmosphere
interaction, the amount of vapour reaching the crater floor is reduced
(by factors of 2-3 depending on season) due to vapour diffusing into the
regolith along the crater walls. The transport of vapour into Gale
crater is also affected by the regional katabatic flow over the
dichotomy boundary, with the largest flux of vapour into the regolith
initially occurring on the northern crater wall, and moving to the
southern wall by early morning. Upslope winds during the day transport
vapour desorbing and mixing out of the regolith up crater walls, where
it can then be transported a few hundred metres into the atmosphere at
convergence boundaries. Regolith-atmosphere interaction limits the
formation of surface ice by reducing water vapour abundances in the
lower atmosphere, though in some seasons ice can still form in the early
morning on eastern crater walls. Subsurface ice amounts are small in all
seasons, with ice only existing in the upper few millimetres of regolith
during the night. The results at Gale crater are representative of the
behaviour at other craters in the mesoscale domain.
  doi = {10.1016/j.icarus.2017.02.010},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Turbet}, M. and {Forget}, F. and {Head}, J.~W. and {Wordsworth}, R.
  title = {{3D modelling of the climatic impact of outflow channel formation events on early Mars}},
  journal = {\icarus},
  archiveprefix = {arXiv},
  eprint = {1701.07886},
  primaryclass = {astro-ph.EP},
  year = 2017,
  volume = 288,
  pages = {10-36},
  abstract = {{Mars was characterized by cataclysmic groundwater-sourced surface
flooding that formed large outflow channels and that may have altered
the climate for extensive periods during the Hesperian era. In
particular, it has been speculated that such events could have induced
significant rainfall and caused the formation of late-stage valley
networks. We present the results of 3-D Global Climate Model simulations
reproducing the short and long term climatic impact of a wide range of
outflow channel formation events under cold ancient Mars conditions. We
find that the most intense of these events (volumes of water up to
10$^{7}$ km$^{3}$ and released at temperatures up to 320 K)
cannot trigger long-term greenhouse global warming, regardless of how
favorable are the external conditions (e.g. obliquity and seasons).
Furthermore, the intensity of the response of the events is
significantly affected by the atmospheric pressure, a parameter not well
constrained for the Hesperian era. Thin atmospheres (P $\lt$ 80 mbar) can
be heated efficiently because of their low volumetric heat capacity,
triggering the formation of a convective plume that is very efficient in
transporting water vapor and ice at the global scale. Thick atmospheres
(P $\gt$ 0.5 bar) have difficulty in producing precipitation far from the
water flow area, and are more efficient in generating snowmelt. In any
case, outflow channel formation events at any atmospheric pressure are
unable to produce rainfall or significant snowmelt at latitudes below
40{\deg}N. As an example, for an outflow channel event (under a 0.2 bar
atmospheric pressure and 45{\deg} obliquity) releasing 10$^{6}$
km$^{3}$ of water heated at 300 K and at a discharge rate of
10$^{9}$ m$^{3}$ s-$^{1}$ , the flow of water reaches
the lowest point of the northern lowlands (around {\sim}70{\deg}N,
30{\deg}W) after {\sim}3 days and forms a 200 m deep lake of 4.2 {\times}
10$^{6}$ km$^{2}$ after {\sim}20 days; the lake becomes
entirely covered by an ice layer after {\sim}500 days. Over the short
term, such an event leaves 6.5 {\times} 10$^{3}$ km$^{3}$ of
ice deposits by precipitation (0.65\% of the initial outflow volume) and
can be responsible for the melting of {\sim}80 km$^{3}$ (0.008\% of
the initial outflow volume; 1\% of the deposited precipitation).
Furthermore, these quantities decrease drastically (faster than
linearly) for lower volumes of released water. Over the long term, we
find that the presence of the ice-covered lake has a climatic impact
similar to a simple body of water ice located in the Northern Plains.

For an obliquity of {\sim}45{\deg} and atmospheric pressures $\gt$ 80 mbar,
we find that the lake ice is transported progressively southward through
the mechanisms of sublimation and adiabatic cooling. At the same time,
and as long as the initial water reservoir is not entirely sublimated (a
lifetime of 10$^{5}$ martian years for the outflow channel event
described above), ice deposits remain in the West Echus Chasma Plateau
region where hints of hydrological activity contemporaneous with outflow
channel formation events have been observed. However, because the high
albedo of ice drives Mars to even colder temperatures, snowmelt produced
by seasonal solar forcing is difficult to attain.
  doi = {10.1016/j.icarus.2017.01.024},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Bertrand}, T. and {Forget}, F.},
  title = {{3D modeling of organic haze in Pluto's atmosphere}},
  journal = {\icarus},
  archiveprefix = {arXiv},
  eprint = {1702.03783},
  primaryclass = {astro-ph.EP},
  keywords = {Pluto, Atmosphere, Haze, Modeling, GCM},
  year = 2017,
  volume = 287,
  pages = {72-86},
  abstract = {{The New Horizons spacecraft, which flew by Pluto on July 14, 2015,
revealed the presence of haze in Pluto's atmosphere that were formed by
CH$_{4}$/N$_{2}$ photochemistry at high altitudes in Pluto's
atmosphere, as on Titan and Triton. In order to help the analysis of the
observations and further investigate the formation of organic haze and
its evolution at global scales, we have implemented a simple
parameterization of the formation of organic haze in our Pluto General
Circulation Model. The production of haze in our model is based on the
different steps of aerosol formation as understood on Titan and Triton:
photolysis of CH$_{4}$ in the upper atmosphere by Lyman-{$\alpha$} UV
radiation, production of various gaseous species, and conversion into
solid particles through accumulation and aggregation processes. The
simulations use properties of aerosols similar to those observed in the
detached haze layer on Titan. We compared two reference simulations ran
with a particle radius of 50  nm: with, and without South Pole
N$_{2}$ condensation. We discuss the impact of the particle radius
and the lifetime of the precursors on the haze distribution. We simulate
CH$_{4}$ photolysis and the haze formation up to 600  km above the
surface. Results show that CH$_{4}$ photolysis in Pluto's
atmosphere in 2015 occurred mostly in the sunlit summer hemisphere with
a peak at an altitude of 250  km, though the interplanetary source of
Lyman-{$\alpha$} flux can induce some photolysis even in the Winter
hemisphere. We obtained an extensive haze up to altitudes comparable
with the observations, and with non-negligible densities up to 500  km
altitude. In both reference simulations, the haze density is not
strongly impacted by the meridional circulation. With No South Pole
N$_{2}$ condensation, the maximum nadir opacity and haze extent is
obtained at the North Pole. With South Pole N$_{2}$ condensation,
the descending parcel of air above the South Pole leads to a
latitudinally more homogeneous haze density with a slight density peak
at the South Pole. The visible opacities obtained from the computed mass
of haze, which is about 2-4 {\times}10$^{-7}$ g cm-$^{2}$ in
the summer hemisphere, are similar for most of the simulation cases and
in the range of 0.001-0.01, which is consistent with recent observations
of Pluto and their interpretation.
  doi = {10.1016/j.icarus.2017.01.016},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Forget}, F. and {Bertrand}, T. and {Vangvichith}, M. and {Leconte}, J. and 
	{Millour}, E. and {Lellouch}, E.},
  title = {{A post-new horizons global climate model of Pluto including the N$_{2}$, CH$_{4}$ and CO cycles}},
  journal = {\icarus},
  keywords = {Pluto, atmosphere, Atmospheres, composition, dynamics},
  year = 2017,
  volume = 287,
  pages = {54-71},
  abstract = {{We have built a new 3D Global Climate Model (GCM) to simulate Pluto as
observed by New Horizons in 2015. All key processes are parametrized on
the basis of theoretical equations, including atmospheric dynamics and
transport, turbulence, radiative transfer, molecular conduction, as well
as phases changes for N$_{2}$, CH$_{2}$ and CO. Pluto's
climate and ice cycles are found to be very sensitive to model
parameters and initial states. Nevertheless, a reference simulation is
designed by running a fast, reduced version of the GCM with simplified
atmospheric transport for 40,000 Earth years to initialize the surface
ice distribution and sub-surface temperatures, from which a
28-Earth-year full GCM simulation is performed. Assuming a topographic
depression in a Sputnik-planum (SP)-like crater on the anti-Charon
hemisphere, a realistic Pluto is obtained, with most N$_{2}$ and
CO ices accumulated in the crater, methane frost covering both
hemispheres except for the equatorial regions, and a surface pressure
near 1.1 Pa in 2015 with an increase between 1988 and 2015, as reported
from stellar occultations. Temperature profiles are in qualitative
agreement with the observations. In particular, a cold atmospheric layer
is obtained in the lowest kilometers above Sputnik Planum, as observed
by New Horizons's REX experiment. It is shown to result from the
combined effect of the topographic depression and N$_{2}$ daytime
sublimation. In the reference simulation with surface N$_{2}$ ice
exclusively present in Sputnik Planum, the global circulation is only
forced by radiative heating gradients and remains relatively weak.
Surface winds are locally induced by topography slopes and by
N$_{2}$ condensation and sublimation around Sputnik Planum.
However, the circulation can be more intense depending on the exact
distribution of surface N$_{2}$ frost. This is illustrated in an
alternative simulation with N$_{2}$ condensing in the South Polar
regions and N$_{2}$ frost covering latitudes between 35{\deg}N and
48{\deg}N. A global condensation flow is then created, inducing strong
surface winds everywhere, a prograde jet in the southern high latitudes,
and an equatorial superrotation likely forced by barotropic
instabilities in the southern jet. Using realistic parameters, the GCM
predict atmospheric concentrations of CO and CH$_{4}$ in good
agreement with the observations. N$_{2}$ and CO do not condense in
the atmosphere, but CH$_{4}$ ice clouds can form during daytime at
low altitude near the regions covered by N$_{2}$ ice (assuming
that nucleation is efficient enough). This global climate model can be
used to study many aspects of the Pluto environment. For instance,
organic hazes are included in the GCM and analysed in a companion paper
(Bertrand and Forget, Icarus, this issue).
  doi = {10.1016/j.icarus.2016.11.038},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Murdoch}, N. and {Kenda}, B. and {Kawamura}, T. and {Spiga}, A. and 
	{Lognonné}, P. and {Mimoun}, D. and {Banerdt}, W.~B.},
  title = {{Estimations of the Seismic Pressure Noise on Mars Determined from Large Eddy Simulations and Demonstration of Pressure Decorrelation Techniques for the Insight Mission}},
  journal = {\ssr},
  archiveprefix = {arXiv},
  eprint = {1704.05664},
  primaryclass = {physics.geo-ph},
  keywords = {Mars, Seismology, Pressure, Atmosphere, Regolith, Geophysics},
  year = 2017,
  abstract = {{The atmospheric pressure fluctuations on Mars induce an elastic response
in the ground that creates a ground tilt, detectable as a seismic signal
on the InSight seismometer SEIS. The seismic pressure noise is modeled
using Large Eddy Simulations (LES) of the wind and surface pressure at
the InSight landing site and a Green's function ground deformation
approach that is subsequently validated via a detailed comparison with
two other methods: a spectral approach, and an approach based on
Sorrells' theory (Sorrells, Geophys. J. Int. 26:71-82, 1971; Sorrells et
al., Nat. Phys. Sci. 229:14-16, 1971). The horizontal accelerations as a
result of the ground tilt due to the LES turbulence-induced pressure
fluctuations are found to be typically {\tilde} 2 - 40 nm/s$^{2}$
in amplitude, whereas the direct horizontal acceleration is two orders
of magnitude smaller and is thus negligible in comparison. The vertical
accelerations are found to be {\tilde} 0.1 - 6 nm/s$^{2}$ in
amplitude. These are expected to be worst-case estimates for the seismic
noise as we use a half-space approximation; the presence at some
(shallow) depth of a harder layer would significantly reduce
quasi-static displacement and tilt effects.

We show that under calm conditions, a single-pressure measurement is
representative of the large-scale pressure field (to a distance of
several kilometers), particularly in the prevailing wind direction.
However, during windy conditions, small-scale turbulence results in a
reduced correlation between the pressure signals, and the
single-pressure measurement becomes less representative of the pressure
field. The correlation between the seismic signal and the pressure
signal is found to be higher for the windiest period because the seismic
pressure noise reflects the atmospheric structure close to the

In the same way that we reduce the atmospheric seismic signal by making
use of a pressure sensor that is part of the InSight Auxiliary Payload
Sensor Suite, we also the use the synthetic noise data obtained from the
LES pressure field to demonstrate a decorrelation strategy. We show that
our decorrelation approach is efficient, resulting in a reduction by a
factor of {\tilde} 5 in the observed horizontal tilt noise (in the wind
direction) and the vertical noise. This technique can, therefore, be
used to remove the pressure signal from the seismic data obtained on
Mars during the InSight mission.
  doi = {10.1007/s11214-017-0343-y},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Mendillo}, M. and {Narvaez}, C. and {Vogt}, M.~F. and {Mayyasi}, M. and 
	{Mahaffy}, P. and {Benna}, M. and {Andersson}, L. and {Campbell}, B. and 
	{N{\v e}mec}, F. and {Ma}, Y.~J. and {Chaufray}, J.-Y. and {Leblanc}, F. and 
	{Gonzalez-Galindo}, F. and {Lopez-Valverde}, M.~{\'A}. and {Forget}, F. and 
	{Jakosky}, B.},
  title = {{MAVEN and the total electron content of the Martian ionosphere}},
  journal = {Journal of Geophysical Research (Space Physics)},
  keywords = {total electron content, Mars, MAVEN, ionosphere},
  year = 2017,
  volume = 122,
  pages = {3526-3537},
  abstract = {{Model studies of the ionosphere of Mars under daytime conditions reveal
that for solar zenith angles of 0{\deg}-40{\deg}, the shapes and
magnitudes of the electron density profiles N$_{e}$(h) change by
only small amounts. This suggests that midday observations made by MAVEN
instruments along slanted orbit segments can be used to represent
vertical profiles. The total electron content (TEC), defined as the
height integral of N$_{e}$(h), is a measure of the cold plasma
reservoir of the Martian ionosphere. During MAVEN's Deep-Dip-\#2 campaign
of April 2015, observations of total ion density by Neutral Gas and Ion
Mass Spectrometer and electron density by Langmuir Probe and Waves from
periapse ( 130 km) to 400 km were used to form
$\lt$TEC$\gt$$_{topside}${\mdash}validated by independent diagnostics
and models. Orbit-by-orbit changes in topside TEC were then used to
assess the magnitudes of plasma escape associated with both large and
small changes in the topside slope of N$_{e}$(h){\mdash}called an
``ionopause episode.'' The TEC changes due to these episodes, generalized
to a global change, resulted in an escape flux of  3-6 {\times}
10$^{24}$ ions/s, an escape rate consistent with prior observation
by Phobos-2, Mars Express, and MAVEN's own in situ studies.
  doi = {10.1002/2016JA023474},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Lefèvre}, M. and {Spiga}, A. and {Lebonnois}, S.},
  title = {{Three-dimensional turbulence-resolving modeling of the Venusian cloud layer and induced gravity waves}},
  journal = {Journal of Geophysical Research (Planets)},
  keywords = {3-D mesoscale modeling, Venus, convective cloud layer, gravity waves},
  year = 2017,
  volume = 122,
  pages = {134-149},
  abstract = {{The impact of the cloud convective layer of the atmosphere of Venus on
the global circulation remains unclear. The recent observations of
gravity waves at the top of the cloud by the Venus Express mission
provided some answers. These waves are not resolved at the scale of
global circulation models (GCM); therefore, we developed an
unprecedented 3-D turbulence-resolving large-eddy simulations (LES)
Venusian model using the Weather Research and Forecast terrestrial
model. The forcing consists of three different heating rates: two
radiative ones for solar and infrared and one associated with the
adiabatic cooling/warming of the global circulation. The rates are
extracted from the Laboratoire de Météorlogie Dynamique
Venus GCM using two different cloud models. Thus, we are able to
characterize the convection and associated gravity waves in function of
latitude and local time. To assess the impact of the global circulation
on the convective layer, we used rates from a 1-D radiative-convective
model. The resolved layer, taking place between 1.0 {\times}
10$^{5}$ and 3.8 {\times} 10$^{4}$ Pa (48-53 km), is
organized as polygonal closed cells of about 10 km wide with vertical
wind of several meters per second. The convection emits gravity waves
both above and below the convective layer leading to temperature
perturbations of several tenths of kelvin with vertical wavelength
between 1 and 3 km and horizontal wavelength from 1 to 10 km. The
thickness of the convective layer and the amplitudes of waves are
consistent with observations, though slightly underestimated. The global
dynamics heating greatly modify the convective layer.
  doi = {10.1002/2016JE005146},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Gilli}, G. and {Lebonnois}, S. and {Gonz{\'a}lez-Galindo}, F. and 
	{L{\'o}pez-Valverde}, M.~A. and {Stolzenbach}, A. and {Lefèvre}, F. and 
	{Chaufray}, J.~Y. and {Lott}, F.},
  title = {{Thermal structure of the upper atmosphere of Venus simulated by a ground-to-thermosphere GCM}},
  journal = {\icarus},
  year = 2017,
  volume = 281,
  pages = {55-72},
  abstract = {{We present here the thermal structure of the upper atmosphere of Venus
predicted by a full self-consistent Venus General Circulation Model
(VGCM) developed at Laboratoire de Météorologie Dynamique
(LMD) and extended up to the thermosphere of the planet. Physical and
photochemical processes relevant at those altitudes, plus a
non-orographic GW parameterisation, have been added. All those
improvements make the LMD-VGCM the only existing ground-to-thermosphere
3D model for Venus: a unique tool to investigate the atmosphere of Venus
and to support the exploration of the planet by remote sounding. The aim
of this paper is to present the model reference results, to describe the
role of radiative, photochemical and dynamical effects in the observed
thermal structure in the upper mesosphere/lower thermosphere of the
planet. The predicted thermal structure shows a succession of warm and
cold layers, as recently observed. A cooling trend with increasing
latitudes is found during daytime at all altitudes, while at nighttime
the trend is inverse above about 110  km, with an atmosphere up to 15 K
warmer towards the pole. The latitudinal variation is even smaller at
the terminator, in agreement with observations. Below about 110  km, a
nighttime warm layer whose intensity decreases with increasing latitudes
is predicted by our GCM. A comparison of model results with a selection
of recent measurements shows an overall good agreement in terms of
trends and order of magnitude. Significant data-model discrepancies may
be also discerned. Among them, thermospheric temperatures are about
40-50 K colder and up to 30 K warmer than measured at terminator and at
nighttime, respectively. The altitude layer of the predicted mesospheric
local maximum (between 100 and 120  km) is also higher than observed.
Possible interpretations are discussed and several sensitivity tests
performed to understand the data-model discrepancies and to propose
future model improvements.
  doi = {10.1016/j.icarus.2016.09.016},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Genthon}, C. and {Piard}, L. and {Vignon}, E. and {Madeleine}, J.-B. and 
	{Casado}, M. and {Gallée}, H.},
  title = {{Atmospheric moisture supersaturation in the near-surface atmosphere at Dome C, Antarctic Plateau}},
  journal = {Atmospheric Chemistry \& Physics},
  year = 2017,
  volume = 17,
  pages = {691-704},
  abstract = {{Supersaturation often occurs at the top of the troposphere where cirrus
clouds form, but is comparatively unusual near the surface where the air
is generally warmer and laden with liquid and/or ice condensation
nuclei. One exception is the surface of the high Antarctic Plateau. One
year of atmospheric moisture measurement at the surface of Dome C on the
East Antarctic Plateau is presented. The measurements are obtained using
commercial hygrometry sensors modified to allow air sampling without
affecting the moisture content, even in the case of supersaturation.
Supersaturation is found to be very frequent. Common unadapted
hygrometry sensors generally fail to report supersaturation, and most
reports of atmospheric moisture on the Antarctic Plateau are thus likely
biased low. The measurements are compared with results from two models
implementing cold microphysics parameterizations: the European Center
for Medium-range Weather Forecasts through its operational analyses, and
the Model Atmosphérique Régional. As in the observations,
supersaturation is frequent in the models but the statistical
distribution differs both between models and observations and between
the two models, leaving much room for model improvement. This is
unlikely to strongly affect estimations of surface sublimation because
supersaturation is more frequent as temperature is lower, and moisture
quantities and thus water fluxes are small anyway. Ignoring
supersaturation may be a more serious issue when considering water
isotopes, a tracer of phase change and temperature, largely used to
reconstruct past climates and environments from ice cores. Because
observations are easier in the surface atmosphere, longer and more
continuous in situ observation series of atmospheric supersaturation can
be obtained than higher in the atmosphere to test parameterizations of
cold microphysics, such as those used in the formation of high-altitude
cirrus clouds in meteorological and climate models.
  doi = {10.5194/acp-17-691-2017},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}