@comment{{This file has been generated by bib2bib 1.97}}
@comment{{Command line: bib2bib --quiet -c year=2019 -c $type="ARTICLE" -oc pub2019.txt -ob pub2019.bib}}
  author = {{Scarica}, Pietro and {Garate-Lopez}, Itziar and {Lebonnois}, Sebastien and
         {Piccioni}, Giuseppe and {Grassi}, Davide and {Migliorini}, Alessandra and
         {Tellmann}, Silvia},
  title = {{Validation of the IPSL Venus GCM Thermal Structure with Venus Express Data}},
  journal = {Atmosphere},
  year = 2019,
  month = sep,
  volume = {10},
  number = {10},
  pages = {584},
  abstract = {{General circulation models (GCMs) are valuable instruments to understand the most peculiar features in the atmospheres of planets and the mechanisms behind their dynamics. Venus makes no exception and it has been extensively studied thanks to GCMs. Here we validate the current version of the Institut Pierre Simon Laplace (IPSL) Venus GCM, by means of a comparison between the modelled temperature field and that obtained from data by the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) and the Venus Express Radio Science Experiment (VeRa) onboard Venus Express. The modelled thermal structure displays an overall good agreement with data, and the cold collar is successfully reproduced at latitudes higher than +/−55°, with an extent and a behavior close to the observed ones. Thermal tides developing in the model appear to be consistent in phase and amplitude with data: diurnal tide dominates at altitudes above 102 Pa pressure level and at high-latitudes, while semidiurnal tide dominates between 102 and 104 Pa, from low to mid-latitudes. The main difference revealed by our analysis is located poleward of 50°, where the model is affected by a second temperature inversion arising at 103 Pa. This second inversion, possibly related to the adopted aerosols distribution, is not observed in data.
  localpdf = {REF/2019Atmos..10..584S.pdf},
  doi = {10.3390/atmos10100584},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Sugimoto}, Norihiko and {Abe}, Mirai and {Kikuchi}, Yukako and
         {Hosono}, Asako and {Ando}, Hiroki and {Takagi}, Masahiro and
         {Garate Lopez}, Itziar and {Lebonnois}, Sebastien and {Ao}, Chi},
  title = {{Observing system simulation experiment for radio occultation measurements of the Venus atmosphere among small satellites}},
  journal = {Journal of Japan Society of Civil Engineers, Ser. A2 (Applied Mechanics (AM))},
  year = 2019,
  month = jan,
  volume = {75},
  number = {2},
  pages = {I_477-I_486},
  abstract = {{We have developed the Venus AFES (atmospheric GCM (general circulation model) for the Earth Simulator) LETKF (local ensemble transform Kalman filter) data assimilation system (VALEDAS) to make full use of observations. In this study, radio occultation measurements among small satellites are evaluated by the observing system simulation experiment (OSSE) of VALEDAS. Idealized observations are prepared by a French Venus Atmospheric GCM in which the cold collar is realistically reproduced. Reproducibility of the cold collar in VALEDAS is tested by several types of observations. The results show that the cold collar is successfully reproduced by assimilating at least 2 or 3 vertical temperature profiles in the polar region every 4 or 6 hours. Therefore, the radio occultation measurements among three satellites in polar orbits would be promising to improve the polar atmospheric structures at about 40–90 km altitudes.
  localpdf = {REF/2019JSCAM..75..477S.pdf},
  doi = {10.2208/jscejam.75.2_I_477},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Lora}, J.~M. and {Tokano}, T. and {Vatant d'Ollone}, J. and 
	{Lebonnois}, S. and {Lorenz}, R.~D.},
  title = {{A model intercomparison of Titan's climate and low-latitude environment}},
  journal = {\icarus},
  keywords = {Titan, Climate, Atmospheres, Meteorology},
  year = 2019,
  volume = 333,
  pages = {113-126},
  abstract = {{Cassini-Huygens provided a wealth of data with which to constrain
numerical models of Titan. Such models have been employed over the last
decade to investigate various aspects of Titan's atmosphere and climate,
and several three-dimensional general circulation models (GCMs) now
exist that simulate Titan with a high degree of fidelity. However,
substantial uncertainties persist, and at the same time no dedicated
intercomparisons have assessed the degree to which these models agree
with each other or the observations. To address this gap, and motivated
by the proposed Dragonfly Titan lander mission, we directly compare
three Titan GCMs to each other and to in situ observations, and also
provide multi-model expectations for the low-latitude environment during
the early northern winter season. Globally, the models qualitatively
agree in their representation of the atmospheric structure and
circulation, though one model severely underestimates meridional
temperature gradients and zonal winds. We find that, at low latitudes,
simulated and observed atmospheric temperatures closely agree in all
cases, while the measured winds above the boundary layer are only
quantitatively matched by one model. Nevertheless, the models simulate
similar near-surface winds, and all indicate these are weak. Likewise,
temperatures and methane content at low latitudes are similar between
models, with some differences that are largely attributable to modeling
assumptions. All models predict environments that closely resemble that
encountered by the Huygens probe, including little or no precipitation
at low latitudes during northern winter. The most significant
differences concern the methane cycle, though the models are least
comparable in this area and substantial uncertainties remain. We suggest
that, while the overall low-latitude environment on Titan at this season
is now fairly well constrained, future in situ measurements and
monitoring will transform our understanding of regional and temporal
variability, atmosphere-surface coupling, Titan's methane cycle, and
modeling thereof.
  doi = {10.1016/j.icarus.2019.05.031},
  adsurl = {},
  localpdf = {REF/2019Icar..333..113L.pdf},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Lee}, Y.~J. and {Jessup}, K.-L. and {Perez-Hoyos}, S. and {Titov}, D.~V. and 
	{Lebonnois}, S. and {Peralta}, J. and {Horinouchi}, T. and {Imamura}, T. and 
	{Limaye}, S. and {Marcq}, E. and {Takagi}, M. and {Yamazaki}, A. and 
	{Yamada}, M. and {Watanabe}, S. and {Murakami}, S.-y. and {Ogohara}, K. and 
	{McClintock}, W.~M. and {Holsclaw}, G. and {Roman}, A.},
  title = {{Long-term Variations of Venus{\rsquo}s 365 nm Albedo Observed by Venus Express, Akatsuki, MESSENGER, and the Hubble Space Telescope}},
  journal = {\aj},
  archiveprefix = {arXiv},
  eprint = {1907.09683},
  primaryclass = {astro-ph.EP},
  keywords = {planets and satellites: atmospheres, planets and satellites: individual: Venus, planets and satellites: terrestrial planets },
  year = 2019,
  volume = 158,
  eid = {126},
  pages = {126},
  abstract = {{An unknown absorber near the cloud-top level of Venus generates a broad
absorption feature from the ultraviolet (UV) to visible, peaking around
360 nm, and therefore plays a critical role in the solar energy
absorption. We present a quantitative study of the variability of the
cloud albedo at 365 nm and its impact on Venus{\rsquo}s solar heating
rates based on an analysis of Venus Express and Akatsuki UV images and
Hubble Space Telescope and MESSENGER UV spectral data; in this analysis,
the calibration correction factor of the UV images of Venus Express
(Venus Monitoring Camera) is updated relative to the Hubble and
MESSENGER albedo measurements. Our results indicate that the 365 nm
albedo varied by a factor of 2 from 2006 to 2017 over the entire planet,
producing a 25\%{\ndash}40\% change in the low-latitude solar heating rate
according to our radiative transfer calculations. Thus, the cloud-top
level atmosphere should have experienced considerable solar heating
variations over this period. Our global circulation model calculations
show that this variable solar heating rate may explain the observed
variations of zonal wind from 2006 to 2017. Overlaps in the timescale of
the long-term UV albedo and the solar activity variations make it
plausible that solar extreme UV intensity and cosmic-ray variations
influenced the observed albedo trends. The albedo variations might also
be linked with temporal variations of the upper cloud SO$_{2}$ gas
abundance, which affects the
H$_{2}$SO$_{4}${\ndash}H$_{2}$O aerosol formation.
  doi = {10.3847/1538-3881/ab3120},
  adsurl = {},
  localpdf = {REF/2019AJ....158..126L.pdf},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Cordier}, D. and {Bonhommeau}, D.~A. and {Port}, S. and {Chevrier}, V. and 
	{Lebonnois}, S. and {Garc{\'{\i}}a-S{\'a}nchez}, F.},
  title = {{The Physical Origin of the Venus Low Atmosphere Chemical Gradient}},
  journal = {\apj},
  archiveprefix = {arXiv},
  eprint = {1908.07781},
  primaryclass = {astro-ph.EP},
  keywords = {planets and satellites: atmospheres, planets and satellites: individual: Venus, planets and satellites: surfaces, planets and satellites: tectonics },
  year = 2019,
  volume = 880,
  eid = {82},
  pages = {82},
  abstract = {{Venus shares many similarities with the Earth, but concomitantly, some
of its features are extremely original. This is especially true for its
atmosphere, where high pressures and temperatures are found at the
ground level. In these conditions, carbon dioxide, the main component of
Venus{\rsquo} atmosphere, is a supercritical fluid. The analysis of
VeGa-2 probe data has revealed the high instability of the region
located in the last few kilometers above the ground level. Recent works
have suggested an explanation based on the existence of a vertical
gradient of molecular nitrogen abundances, around 5 ppm per meter. Our
goal was then to identify which physical processes could lead to the
establishment of this intriguing nitrogen gradient, in the deep
atmosphere of Venus. Using an appropriate equation of state for the
binary mixture CO$_{2}${\ndash}N$_{2}$ under supercritical
conditions, and also molecular dynamics simulations, we have
investigated the separation processes of N$_{2}$ and
CO$_{2}$ in the Venusian context. Our results show that molecular
diffusion is strongly inefficient, and potential phase separation is an
unlikely mechanism. We have compared the quantity of CO$_{2}$
required to form the proposed gradient with what could be released by a
diffuse degassing from a low volcanic activity. The needed fluxes of
CO$_{2}$ are not so different from what can be measured over some
terrestrial volcanic systems, suggesting a similar effect at work on
  doi = {10.3847/1538-4357/ab27bd},
  adsurl = {},
  localpdf = {REF/2019ApJ...880...82C.pdf},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Encrenaz}, T. and {Greathouse}, T.~K. and {Marcq}, E. and {Sagawa}, H. and 
	{Widemann}, T. and {B\'ezard}, B. and {Fouchet}, T. and {Lef\`evre}, F. and 
	{Lebonnois}, S. and {Atreya}, S.~K. and {Lee}, Y.~J. and {Giles}, R. and 
	{Watanabe}, S.},
  title = {{HDO and SO$_{2}$ thermal mapping on Venus. IV. Statistical analysis of the SO$_{2}$ plumes}},
  journal = {\aap},
  keywords = {planets and satellites: atmospheres, planets and satellites: terrestrial planets, infrared: planetary systems},
  year = 2019,
  volume = 623,
  eid = {A70},
  pages = {A70},
  abstract = {{Since January 2012 we have been monitoring the behavior of sulfur
dioxide and water on Venus, using the Texas Echelon Cross-Echelle
Spectrograph (TEXES) imaging spectrometer at the NASA InfraRed Telescope
Facility (IRTF, Mauna Kea Observatory). We present here the observations
obtained between January 2016 and September 2018. As in the case of our
previous runs, data were recorded around 1345 cm$^{-1}$ (7.4
{$\mu$}m). The molecules SO$_{2}$, CO$_{2}$, and HDO (used as a
proxy for H$_{2}$O) were observed, and the cloudtop of Venus was
probed at an altitude of about 64 km. The volume mixing ratio of
SO$_{2}$ was estimated using the SO$_{2}$/CO$_{2}$
line depth ratios of weak transitions; the H$_{2}$O volume mixing
ratio was derived from the HDO/CO$_{2}$ line depth ratio, assuming
a D/H ratio of 200 times the Vienna Standard Mean Ocean Water (VSMOW).
As reported in our previous analyses, the SO$_{2}$ mixing ratio
shows strong variations with time and also over the disk, showing
evidence of the formation of SO$_{2}$ plumes with a lifetime of a
few hours; in contrast, the H$_{2}$O abundance is remarkably
uniform over the disk and shows moderate variations as a function of
time. We performed a statistical analysis of the behavior of the
SO$_{2}$ plumes, using all TEXES data between 2012 and 2018. They
appear mostly located around the equator. Their distribution as a
function of local time seems to show a depletion around noon; we do not
have enough data to confirm this feature definitely. The distribution of
SO$_{2}$ plumes as a function of longitude shows no clear feature,
apart from a possible depletion around 100E-150E and around 300E-360E.
There seems to be a tendency for the H$_{2}$O volume mixing ratio
to decrease after 2016, and for the SO$_{2}$ mixing ratio to
increase after 2014. However, we see no clear anti-correlation between
the SO$_{2}$ and H$_{2}$O abundances at the cloudtop,
neither on the individual maps nor over the long term. Finally, there is
a good agreement between the TEXES results and those obtained in the UV
range (SPICAV/Venus Express and UVI/Akatsuki) at a slightly higher
altitude. This agreement shows that SO$_{2}$ observations obtained
in the thermal infrared can be used to extend the local time coverage of
the SO$_{2}$ measurements obtained in the UV range.
  doi = {10.1051/0004-6361/201833511},
  adsurl = {},
  localpdf = {REF/2019A_26A...623A..70E.pdf},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}