pub2006.bib

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@article{2006P&SS...54.1298F,
  author = {{Formisano}, V. and {Angrilli}, F. and {Arnold}, G. and {Atreya}, S. and 
	{Baines}, K.~H. and {Bellucci}, G. and {Bezard}, B. and {Billebaud}, F. and 
	{Biondi}, D. and {Blecka}, M.~I. and {Colangeli}, L. and {Comolli}, L. and 
	{Crisp}, D. and {D'Amore}, M. and {Encrenaz}, T. and {Ekonomov}, A. and 
	{Esposito}, F. and {Fiorenza}, C. and {Fonti}, S. and {Giuranna}, M. and 
	{Grassi}, D. and {Grieger}, B. and {Grigoriev}, A. and {Helbert}, J. and 
	{Hirsch}, H. and {Ignatiev}, N. and {Jurewicz}, A. and {Khatuntsev}, I. and 
	{Lebonnois}, S. and {Lellouch}, E. and {Mattana}, A. and {Maturilli}, A. and 
	{Mencarelli}, E. and {Michalska}, M. and {Lopez Moreno}, J. and 
	{Moshkin}, B. and {Nespoli}, F. and {Nikolsky}, Y. and {Nuccilli}, F. and 
	{Orleanski}, P. and {Palomba}, E. and {Piccioni}, G. and {Rataj}, M. and 
	{Rinaldi}, G. and {Rossi}, M. and {Saggin}, B. and {Stam}, D. and 
	{Titov}, D. and {Visconti}, G. and {Zasova}, L.},
  title = {{The planetary fourier spectrometer (PFS) onboard the European Venus Express mission}},
  journal = {\planss},
  year = 2006,
  volume = 54,
  pages = {1298-1314},
  abstract = {{The planetary fourier spectrometer (PFS) for the Venus Express mission
is an infrared spectrometer optimized for atmospheric studies. This
instrument has a short wavelength (SW) channel that covers the spectral
range from 1700 to 11400 cm $^{-1}$ (0.9-5.5 {$\mu$}m) and a long
wavelength (LW) channel that covers 250-1700 cm $^{-1}$ (5.5-45
{$\mu$}m). Both channels have a uniform spectral resolution of 1.3 cm
$^{-1}$. The instrument field of view FOV is about 1.6 {\deg}
(FWHM) for the short wavelength channel and 2.8 {\deg} for the LW channel
which corresponds to a spatial resolution of 7 and 12 km when Venus is
observed from an altitude of 250 km. PFS can provide unique data
necessary to improve our knowledge not only of the atmospheric
properties but also surface properties (temperature) and the
surface-atmosphere interaction (volcanic activity). PFS works primarily
around the pericentre of the orbit, only occasionally observing Venus
from larger distances. Each measurements takes 4.5 s, with a repetition
time of 11.5 s. By working roughly 1.5 h around pericentre, a total of
460 measurements per orbit will be acquired plus 60 for calibrations.
PFS is able to take measurements at all local times, enabling the
retrieval of atmospheric vertical temperature profiles on both the day
and the night side. The PFS measures a host of atmospheric and surface
phenomena on Venus. These include the:(1) thermal surface flux at
several wavelengths near 1 {$\mu$}m, with concurrent constraints on surface
temperature and emissivity (indicative of composition); (2) the
abundances of several highly-diagnostic trace molecular species; (3)
atmospheric temperatures from 55 to 100 km altitude; (4) cloud opacities
and cloud-tracked winds in the lower-level cloud layers near 50-km
altitudes; (5) cloud top pressures of the uppermost haze/cloud region
near 70-80 km altitude; and (6) oxygen airglow near the 100 km level.
All of these will be observed repeatedly during the 500-day nominal
mission of Venus Express to yield an increased understanding of
meteorological, dynamical, photochemical, and thermo-chemical processes
in the Venus atmosphere. Additionally, PFS will search for and
characterize current volcanic activity through spatial and temporal
anomalies in both the surface thermal flux and the abundances of
volcanic trace species in the lower atmosphere. Measurement of the 15
{$\mu$}m CO $_{2}$ band is very important. Its profile gives, by
means of a complex temperature profile retrieval technique, the vertical
pressure-temperature relation, basis of the global atmospheric study.
PFS is made of four modules called O, E, P and S being, respectively,
the interferometer and proximity electronics, the digital control unit,
the power supply and the pointing device.
}},
  doi = {10.1016/j.pss.2006.04.033},
  adsurl = {http://adsabs.harvard.edu/abs/2006P%26SS...54.1298F},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2006A&A...459..265E,
  author = {{Encrenaz}, T. and {Fouchet}, T. and {Melchiorri}, R. and {Drossart}, P. and 
	{Gondet}, B. and {Langevin}, Y. and {Bibring}, J.-P. and {Forget}, F. and 
	{Bézard}, B.},
  title = {{Seasonal variations of the martian CO over Hellas as observed by OMEGA/Mars Express}},
  journal = {\aap},
  keywords = {planets and satellites: individual: Mars, infrared: solar system},
  year = 2006,
  volume = 459,
  pages = {265-270},
  abstract = {{The OMEGA imaging spectrometer aboard Mars Express has been used to
study the evolution of the CO abundance over the Hellas basin, as a
function of the seasonal cycle. In spite of significant uncertainties,
due to the low intensity of the (2-0) CO band at 2.3 {$\mu$}m, these data
allow to search for spatial variations over Hellas, where the surface
pressure and the CO band depth are maximum. The OMEGA data suggest an
enhancement over Hellas at Ls = 130-150 deg (end of southern winter), by
a factor of about 2 with regard to Ls = 330-350 deg (end of northern
summer). This behavior is to be compared with the evolution of argon,
another non-condensible species which also shows strong variations with
Ls at southern latitudes (Sprague et al. 2004). This result appears also
consistent with the GCM predictions which indicate an enrichment by a
factor of about 2 of non-condensible species over Hellas during southern
winter (Forget et al. 2006).
}},
  doi = {10.1051/0004-6361:20065586},
  adsurl = {http://adsabs.harvard.edu/abs/2006A%26A...459..265E},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2006JGRE..11110S90B,
  author = {{Bertaux}, J.-L. and {Korablev}, O. and {Perrier}, S. and {Quémerais}, E. and 
	{Montmessin}, F. and {Leblanc}, F. and {Lebonnois}, S. and {Rannou}, P. and 
	{Lefèvre}, F. and {Forget}, F. and {Fedorova}, A. and {Dimarellis}, E. and 
	{Reberac}, A. and {Fonteyn}, D. and {Chaufray}, J.~Y. and {Guibert}, S.
	},
  title = {{SPICAM on Mars Express: Observing modes and overview of UV spectrometer data and scientific results}},
  journal = {Journal of Geophysical Research (Planets)},
  keywords = {Planetary Sciences: Solid Surface Planets: Atmospheres (0343, 1060), Planetary Sciences: Solid Surface Planets: Aurorae and airglow, Planetary Sciences: Solid Surface Planets: Composition (1060, 3672), Planetary Sciences: Solid Surface Planets: Instruments and techniques, Planetary Sciences: Solid Surface Planets: General or miscellaneous},
  year = 2006,
  volume = 111,
  number = e10,
  eid = {E10S90},
  pages = {E10S90},
  abstract = {{This paper is intended as an introduction to several companion papers
describing the results obtained by the SPICAM instrument on board Mars
Express orbiter. SPICAM is a lightweight (4.7 kg) UV-IR dual
spectrometer dedicated primarily to the study of the atmosphere of Mars.
The SPICAM IR spectrometer and its results are described in another
companion paper. SPICAM is the first instrument to perform stellar
occultations at Mars, and its UV imaging spectrometer (118-320 nm,
resolution \~{}1.5 nm, intensified CCD detector) was designed primarily to
obtain atmospheric vertical profiles by stellar occultation. The
wavelength range was dictated by the strong UV absorption of
CO$_{2}$ ({$\lambda$} $\lt$ 200 nm) and the strong Hartley ozone
absorption (220-280 nm). The UV spectrometer is described in some
detail. The capacity to orient the spacecraft allows a great versatility
of observation modes: nadir and limb viewing (both day and night) and
solar and stellar occultations, which are briefly described. The
absolute calibration is derived from the observation of UV-rich stars.
An overview of a number of scientific results is presented, already
published or found in more detail as companion papers in this special
section. SPICAM UV findings are relevant to CO$_{2}$, ozone, dust,
cloud vertical profiles, the ozone column, dayglow, and nightglow. This
paper is particularly intended to provide the incentive for SPICAM data
exploitation, available to the whole scientific community in the ESA
data archive, and to help the SPICAM data users to better understand the
instrument and the various data collection modes, for an optimized
scientific return.
}},
  doi = {10.1029/2006JE002690},
  adsurl = {http://adsabs.harvard.edu/abs/2006JGRE..11110S90B},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2006JGRE..111.9S09M,
  author = {{Montmessin}, F. and {Quémerais}, E. and {Bertaux}, J.~L. and 
	{Korablev}, O. and {Rannou}, P. and {Lebonnois}, S.},
  title = {{Stellar occultations at UV wavelengths by the SPICAM instrument: Retrieval and analysis of Martian haze profiles}},
  journal = {Journal of Geophysical Research (Planets)},
  keywords = {History of Geophysics: Planetology, Planetary Sciences: Solid Surface Planets: Atmospheres (0343, 1060), Planetary Sciences: Solid Surface Planets: Meteorology (3346), Atmospheric Composition and Structure: Aerosols and particles (0345, 4801, 4906), Atmospheric Composition and Structure: Planetary atmospheres (5210, 5405, 5704)},
  year = 2006,
  volume = 111,
  eid = {E09S09},
  pages = {E09S09},
  abstract = {{Observations made by the SPICAM ultraviolet spectrometer on board the
Mars Express orbiter are presented. We focus on several hundreds of
atmospheric profiles which have been collected over 3/4 of a Martian
year by making use of the stellar occultation technique. The typical
structure of the Martian haze possesses at least one discrete layer (60\%
of all cases) standing over an extended portion wherein opacity
continuously increases down to the surface. Differences of morphology
are, however, noted between profiles observed near the equator and
profiles collected elsewhere. The Martian haze exhibits a pronounced
seasonal signal manifested by variations of the maximum elevation at
which particles are observed. For reasons related to both convective
activity and changes in the hygropause level, cold regions display a
much lower hazetop than warm regions. Using UV spectrometry data, we put
constraints on haze microphysical properties. Vertical variations of
particle size are keyed to variations of opacity; e.g., an increase of
particle size is systematically observed near extinction peaks. This is
the likely consequence of cloud formation which results into a local
increase of particle cross section. Despite marked differences of
aerosol profiles between low and high latitudes, haze properties above
60 km remain invariant, possibly reflecting the long-term presence of a
background submicronic particle population. Several profiles have been
analyzed in more detail to extract properties of detached cloud layers
lofted above 40 km. Their optical depth ranges between 0.01 and 0.1 in
the visible. Estimation of cloud particle size is technically restricted
because of SPICAM wavelength sampling, but it generally yields a minimum
radius value of about 0.3 {$\mu$}m, while several estimates are consistent
with a robust 0.1-0.2 {$\mu$}m. This crystal size, significantly smaller
than the 1 to 4 {$\mu$}m associated with recently classified type I and II
clouds, suggests that a different class of clouds, henceforth type III
clouds, can be extracted from our data. Observations made in the
southern winter polar night indicate a very distinct aerosol behavior
where particles are less abundant ({$\tau$} $\lt$ 0.1), confined to lower
heights (vertical profile consistent with a Conrath parameter exceeding
0.04) and made of particles having a radius on the order of 0.1 {$\mu$}m.
This shows that the Martian polar night is a region with a very clean
atmosphere and with a distinct type of aerosols.
}},
  doi = {10.1029/2005JE002662},
  adsurl = {http://adsabs.harvard.edu/abs/2006JGRE..111.9S09M},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2006JGRE..111.9S06P,
  author = {{Perrier}, S. and {Bertaux}, J.~L. and {Lefèvre}, F. and 
	{Lebonnois}, S. and {Korablev}, O. and {Fedorova}, A. and {Montmessin}, F.
	},
  title = {{Global distribution of total ozone on Mars from SPICAM/MEX UV measurements}},
  journal = {Journal of Geophysical Research (Planets)},
  keywords = {Atmospheric Composition and Structure: Planetary atmospheres (5210, 5405, 5704), Planetary Sciences: Solar System Objects: Mars, Planetary Sciences: Astrobiology: Planetary atmospheres, clouds, and hazes (0343)},
  year = 2006,
  volume = 111,
  eid = {E09S06},
  pages = {E09S06},
  abstract = {{The dual UV/IR spectrometer SPICAM on board the European mission Mars
Express is dedicated to monitoring the Martian atmosphere and has
recorded spectra for more than one Martian year, from January 2004 to
April 2006, over a large range of latitudes and longitudes. SPICAM UV
spectra were recorded on the day side in a nadir geometry, in the
110-320 nm range, allowing measurement of ozone absorption around 250
nm. The method used to retrieve column-integrated ozone quantities is
described. A full radiative transfer forward model of the radiance
factor is used in an iterative loop to fit the data with four
parameters: the surface albedo at 210 and 300 nm, the dust opacity, and
the total ozone column. The analysis of the complete data set is
presented. The global climatology of ozone on Mars is retrieved for the
first time with spatial and temporal coverage. The most significant
findings are (1) large increases in the ozone column density at high
latitudes during late winter-early spring of each hemisphere that
totally disappear during summer, (2) a large variability of the northern
spring content related to the polar vortex oscillations, (3) low ozone
columns in the equatorial regions all year long, and (4) local
variations of the ozone column related to topography, mainly above
Hellas Planitia. A good overall agreement is obtained comparing SPICAM
data to predictions of a Chemical General Circulation Model. However,
significant discrepancies in total abundances are found near northern
spring when ozone reaches its annual peak. These results will help
further understanding of the dynamics and chemistry of Mars atmosphere.
}},
  doi = {10.1029/2006JE002681},
  adsurl = {http://adsabs.harvard.edu/abs/2006JGRE..111.9S06P},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2006JGRE..111.9S05L,
  author = {{Lebonnois}, S. and {Quémerais}, E. and {Montmessin}, F. and 
	{Lefèvre}, F. and {Perrier}, S. and {Bertaux}, J.-L. and 
	{Forget}, F.},
  title = {{Vertical distribution of ozone on Mars as measured by SPICAM/Mars Express using stellar occultations}},
  journal = {Journal of Geophysical Research (Planets)},
  keywords = {Planetary Sciences: Solar System Objects: Mars, Planetary Sciences: Solid Surface Planets: Composition (1060, 3672), Planetary Sciences: Solid Surface Planets: Remote sensing, Atmospheric Composition and Structure: Planetary atmospheres (5210, 5405, 5704)},
  year = 2006,
  volume = 111,
  eid = {E09S05},
  pages = {E09S05},
  abstract = {{The ultraviolet spectrometer of the SPICAM instrument on board the
European Mars Express mission has performed stellar occultations to
probe the atmosphere. Vertical profiles of ozone are retrieved from
inversion of transmission spectra in the altitude range 20-30 to 70 km.
They are analyzed here as functions of latitude and season of the
observations. These occultations have been monitored on the night side,
from northern spring equinox (L$_{s}$ = 8{\deg}) to northern winter
solstice (L$_{s}$ = 270{\deg}). The profiles show the presence of
two ozone layers: (1) one located near the surface, the top of which is
visible below 30 km altitude, and (2) one layer located in the altitude
range 30 to 60 km, a feature that is highly variable with latitude and
season. This layer is first seen after L$_{s}$ = 11{\deg}, and the
ozone abundance at the peak tends to increase until L$_{s}$ \~{}
40{\deg}, when it stabilizes around 6-8 {\times} 10$^{9}$
cm$^{-3}$. After southern winter solstice (L$_{s}$ \~{}
100{\deg}), the peak abundance starts decreasing again, and this ozone
layer is no longer detected after L$_{s}$ \~{} 130{\deg}. A recent
model (Lefèvre et al., 2004) predicted the presence of these
ozone layers, the altitude one being only present at night. Though the
agreement between model and observations is quite good, this nocturnal
altitude layer is present in SPICAM data over a less extended period
than predicted. Though a possible role of heterogeneous chemistry is not
excluded, this difference is probably linked to the seasonal evolution
of the vertical distribution of water vapor.
}},
  doi = {10.1029/2005JE002643},
  adsurl = {http://adsabs.harvard.edu/abs/2006JGRE..111.9S05L},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2006A&A...456..761H,
  author = {{Hirtzig}, M. and {Coustenis}, A. and {Gendron}, E. and {Drossart}, P. and 
	{Negr{\~a}o}, A. and {Combes}, M. and {Lai}, O. and {Rannou}, P. and 
	{Lebonnois}, S. and {Luz}, D.},
  title = {{Monitoring atmospheric phenomena on Titan}},
  journal = {\aap},
  keywords = {planets and satellites: individual: Titan, instrumentation: adaptive optics},
  year = 2006,
  volume = 456,
  pages = {761-774},
  abstract = {{For the past 8 years (1998-2005), we have used adaptive optics imaging
(with VLT/NACO and CFHT/PUEO) to explore Titan's atmosphere, which is
currently scrutinized in situ by the Cassini-Huygens mission. In the
course of our work, we have found variations, such as as seasonal and
diurnal effects, as well as temporary features in the southern polar
region. The north-south asymmetry is shown to have changed since 2000 in
the near-IR and to be currently organized in a brighter northern than
southern pole. We study this evolution here. With our data, we also have
new significant statistical evidence of diurnal effects in Titan's
stratosphere, with a brighter (as much as 19\%) morning limb appearing in
our images in many cases, when the phase effect is expected on the
evening side. The southern bright feature is probably a time-limited
seasonal and/or meteorological phenomenon, revolving around the south
pole (confined in its motion within the 80{\deg}S parallel) and located
somewhere in the upper troposphere (18-40 km of altitude). Its behavior
and possible nature are discussed here.
}},
  doi = {10.1051/0004-6361:20053381},
  adsurl = {http://adsabs.harvard.edu/abs/2006A%26A...456..761H},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2006P&SS...54..774O,
  author = {{OMEGA Team} and {Melchiorri}, R. and {Drossart}, P. and {Fouchet}, T. and 
	{Bézard}, B. and {Forget}, F. and {Gendrin}, A. and {Bibring}, J.~P. and 
	{Manaud}, N. and {OMEGA Team}},
  title = {{A simulation of the OMEGA/Mars Express observations: Analysis of the atmospheric contribution}},
  journal = {\planss},
  year = 2006,
  volume = 54,
  pages = {774-783},
  abstract = {{Spectral images of Mars obtained by the Mars Express/OMEGA experiment in
the near infrared are the result of a complex combination of
atmospheric, aerosol and ground features. Retrieving the atmospheric
information from the data is important, not only to decorrelate
mineralogical against atmospheric features, but also to retrieve the
atmospheric variability. Once the illumination conditions have been
taken into account, the main source of variation on the CO$_{2}$
absorption is due to the altitude of the surface, which governs
atmospheric pressure variation by more than an order of magnitude
between the summit of Olympus Mons down to the bottom of Valles
Marineris. In this article we present a simplified atmospheric spectral
model without scattering, specially developed for the OMEGA
observations, which is used to retrieve the local topography through the
analysis of the 2.0{$\mu$}mCO$_{2}$ band. OMEGA atmospheric
observations increase the horizontal resolution compared to MOLA
altimetry measurements, and therefore complement the mineralogical
studies from the same instrument. Finally, residual variations of the
pressure can be related to atmospheric structure variation.
}},
  doi = {10.1016/j.pss.2006.04.014},
  adsurl = {http://adsabs.harvard.edu/abs/2006P%26SS...54..774O},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2006P&SS...54..774M,
  author = {{Melchiorri}, R. and {Drossart}, P. and {Fouchet}, T. and {Bézard}, B. and 
	{Forget}, F. and {Gendrin}, A. and {Bibring}, J.~P. and {Manaud}, N. and 
	{Omega Team}},
  title = {{A simulation of the OMEGA/Mars Express observations: Analysis of the atmospheric contribution}},
  journal = {\planss},
  year = 2006,
  volume = 54,
  pages = {774-783},
  abstract = {{Spectral images of Mars obtained by the Mars Express/OMEGA experiment in
the near infrared are the result of a complex combination of
atmospheric, aerosol and ground features. Retrieving the atmospheric
information from the data is important, not only to decorrelate
mineralogical against atmospheric features, but also to retrieve the
atmospheric variability. Once the illumination conditions have been
taken into account, the main source of variation on the CO$_{2}$
absorption is due to the altitude of the surface, which governs
atmospheric pressure variation by more than an order of magnitude
between the summit of Olympus Mons down to the bottom of Valles
Marineris. In this article we present a simplified atmospheric spectral
model without scattering, specially developed for the OMEGA
observations, which is used to retrieve the local topography through the
analysis of the 2.0{$\mu$}mCO$_{2}$ band. OMEGA atmospheric
observations increase the horizontal resolution compared to MOLA
altimetry measurements, and therefore complement the mineralogical
studies from the same instrument. Finally, residual variations of the
pressure can be related to atmospheric structure variation.
}},
  doi = {10.1016/j.pss.2006.04.014},
  adsurl = {http://adsabs.harvard.edu/abs/2006P%26SS...54..774M},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2006Natur.442..790L,
  author = {{Langevin}, Y. and {Douté}, S. and {Vincendon}, M. and {Poulet}, F. and 
	{Bibring}, J.-P. and {Gondet}, B. and {Schmitt}, B. and {Forget}, F.
	},
  title = {{No signature of clear CO$_{2}$ ice from the `cryptic' regions in Mars' south seasonal polar cap}},
  journal = {\nat},
  year = 2006,
  volume = 442,
  pages = {790-792},
  abstract = {{The seasonal polar ice caps of Mars are composed mainly of
CO$_{2}$ ice. A region of low ($\lt$ 30\%) albedo has been observed
within the south seasonal cap during early to mid-spring. The low
temperature of this `cryptic region' has been attributed to a clear slab
of nearly pure CO$_{2}$ ice, with the low albedo resulting from
absorption by the underlying surface. Here we report near-infrared
imaging spectroscopy of the south seasonal cap. The deep and broad
CO$_{2}$ absorption bands that are expected in the near-infrared
with a thick transparent slab of CO$_{2}$ ice are not observed.
Models of the observed spectra indicate that the low albedo results from
extensive dust contamination close to the surface of a CO$_{2}$
ice layer, which could be linked to atmospheric circulation patterns.
The strength of the CO$_{2}$ absorption increases after
mid-spring, so part of the dust is either carried away or buried more
deeply in the ice layer during the CO$_{2}$ ice sublimation
process.
}},
  doi = {10.1038/nature05012},
  adsurl = {http://adsabs.harvard.edu/abs/2006Natur.442..790L},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2006Icar..183..403M,
  author = {{Montmessin}, F. and {Bertaux}, J.-L. and {Quémerais}, E. and 
	{Korablev}, O. and {Rannou}, P. and {Forget}, F. and {Perrier}, S. and 
	{Fussen}, D. and {Lebonnois}, S. and {Rébérac}, A. and 
	{Dimarellis}, E.},
  title = {{Subvisible CO $_{2}$ ice clouds detected in the mesosphere of Mars}},
  journal = {\icarus},
  year = 2006,
  volume = 183,
  pages = {403-410},
  abstract = {{The formation of CO $_{2}$ ice clouds in the upper atmosphere of
Mars has been suggested in the past on the basis of a few temperature
profiles exhibiting portions colder than CO $_{2}$ frost point.
However, the corresponding clouds were never observed. In this paper, we
discuss the detection of the highest clouds ever observed on Mars by the
SPICAM ultraviolet spectrometer on board Mars Express spacecraft.
Analyzing stellar occultations, we detected several mesospheric detached
layers at about 100 km in the southern winter subtropical latitudes, and
found that clouds formed where simultaneous temperature measurements
indicated that CO $_{2}$ was highly supersaturated and probably
condensing. Further analysis of the spectra reveals a cloud opacity in
the subvisible range and ice crystals smaller than 100 nm in radius.
These layers are therefore similar in nature as the noctilucent clouds
which appear on Earth in the polar mesosphere. We interpret these
phenomena as CO $_{2}$ ice clouds forming inside supersaturated
pockets of air created by upward propagating thermal waves. This
detection of clouds in such an ultrararefied and supercold atmosphere
raises important questions about the martian middle-atmosphere dynamics
and microphysics. In particular, the presence of condensates at such
high altitudes begs the question of the origin of the condensation
nuclei.
}},
  doi = {10.1016/j.icarus.2006.03.015},
  adsurl = {http://adsabs.harvard.edu/abs/2006Icar..183..403M},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2006Icar..183..396F,
  author = {{Fast}, K. and {Kostiuk}, T. and {Hewagama}, T. and {A'Hearn}, M.~F. and 
	{Livengood}, T.~A. and {Lebonnois}, S. and {Lefèvre}, F.
	},
  title = {{Ozone abundance on Mars from infrared heterodyne spectra. II. Validating photochemical models}},
  journal = {\icarus},
  year = 2006,
  volume = 183,
  pages = {396-402},
  abstract = {{Ozone is an important observable tracer of martian photochemistry,
including odd hydrogen (HO $_{x}$) species important to the
chemistry and stability of the martian atmosphere. Infrared heterodyne
spectroscopy with spectral resolution {\ges}10 provides the only
ground-based direct access to ozone absorption features in the martian
atmosphere. Ozone abundances were measured with the Goddard Infrared
Heterodyne Spectrometer and the Heterodyne Instrument for Planetary Wind
and Composition at the NASA Infrared Telescope Facility on Mauna Kea,
Hawai'i. Retrieved total ozone column abundances from various latitudes
and orbital positions ( L=40{\deg}, 74{\deg}, 102{\deg}, 115{\deg},
202{\deg}, 208{\deg}, 291{\deg}) are compared to those predicted by the
first three-dimensional gas phase photochemical model of the martian
atmosphere [Lefèvre, F., Lebonnois, S., Montmessin, F., Forget,
F., 2004. J. Geophys. Res. 109, doi:10.1029/2004JE002268. E07004].
Observed and modeled ozone abundances show good agreement at all
latitudes at perihelion orbital positions ( L=202{\deg}, 208{\deg},
291{\deg}). Observed low-latitude ozone abundances are significantly
higher than those predicted by the model at aphelion orbital positions (
L=40{\deg}, 74{\deg}, 115{\deg}). Heterogeneous loss of odd hydrogen onto
water ice cloud particles would explain the discrepancy, as clouds are
observed at low latitudes around aphelion on Mars.
}},
  doi = {10.1016/j.icarus.2006.03.012},
  adsurl = {http://adsabs.harvard.edu/abs/2006Icar..183..396F},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2006Icar..183...30B,
  author = {{Baratoux}, D. and {Mangold}, N. and {Forget}, F. and {Cord}, A. and 
	{Pinet}, P. and {Daydou}, Y. and {Jehl}, A. and {Masson}, P. and 
	{Neukum}, G. and {The HRSC CO-Investigator Team}},
  title = {{The role of the wind-transported dust in slope streaks activity: Evidence from the HRSC data}},
  journal = {\icarus},
  year = 2006,
  volume = 183,
  pages = {30-45},
  abstract = {{Slope streaks are gravity-driven albedo features observed on martian
slopes since the Viking missions. The debated mechanism of formation
could involve alternatively dry granular flow or wet mass wasting. A
systematic mapping of slope streaks from the High Resolution Stereo
Camera is presented in this paper. Two regions known for their slope
streaks activity have been studied, the first one is located close to
Cerberus lava flow, and the second one is inside the Olympus Mons
Aureole. The statistics of slope streaks shapes measured from
orthorectified images confirm previous results from Mars Orbiter Camera
surveys. Preferential orientations of slope streaks are reported. Slope
streaks occur preferentially on west facing slopes at latitudes lower
than 30{\deg} N for Olympus and on south-west facing slopes for Cerberus.
Wind directions derived from a General Circulation Model during the
dusty season correlate with these orientations. Furthermore, west facing
slopes at Olympus have a thicker dust cover. These observations indicate
that slope streaks are dust avalanches controlled by the preferential
accumulation of dust in the downstream side of the wind flow. The
paucity of slope streaks at high latitudes and their preferential
orientation on south-facing slopes have been presented as an evidence
for a potential role of H $_{2}$O phase transition in triggering
or flow. The potential role of H $_{2}$O cannot be ruled out from
our observations but the dust avalanche model together with the
atmospheric circulation could potentially explain all observations. The
role of H $_{2}$O might be limited to a stabilizing effect of dust
deposits on northward facing slopes at intermediate latitudes (30{\deg}
N-33{\deg} N) and on all slopes further north.
}},
  doi = {10.1016/j.icarus.2006.01.023},
  adsurl = {http://adsabs.harvard.edu/abs/2006Icar..183...30B},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2006Sci...312..400B,
  author = {{Bibring}, J.-P. and {Langevin}, Y. and {Mustard}, J.~F. and 
	{Poulet}, F. and {Arvidson}, R. and {Gendrin}, A. and {Gondet}, B. and 
	{Mangold}, N. and {Pinet}, P. and {Forget}, F. and {OMEGA Team} and 
	{Berthé}, M. and {Gomez}, C. and {Jouglet}, D. and {Soufflot}, A. and 
	{Vincendon}, M. and {Combes}, M. and {Drossart}, P. and {Encrenaz}, T. and 
	{Fouchet}, T. and {Merchiorri}, R. and {Belluci}, G. and {Altieri}, F. and 
	{Formisano}, V. and {Capaccioni}, F. and {Cerroni}, P. and {Coradini}, A. and 
	{Fonti}, S. and {Korablev}, O. and {Kottsov}, V. and {Ignatiev}, N. and 
	{Moroz}, V. and {Titov}, D. and {Zasova}, L. and {Loiseau}, D. and 
	{Pinet}, P. and {Doute}, S. and {Schmitt}, B. and {Sotin}, C. and 
	{Hauber}, E. and {Hoffmann}, H. and {Jaumann}, R. and {Keller}, U. and 
	{Arvidson}, R. and {Duxbury}, T. and {Neukum}, G.},
  title = {{Global Mineralogical and Aqueous Mars History Derived from OMEGA/Mars Express Data}},
  journal = {Science},
  year = 2006,
  volume = 312,
  pages = {400-404},
  abstract = {{Global mineralogical mapping of Mars by the Observatoire pour la
Mineralogie, l'Eau, les Glaces et l'Activité (OMEGA) instrument
on the European Space Agency's Mars Express spacecraft provides new
information on Mars' geological and climatic history. Phyllosilicates
formed by aqueous alteration very early in the planet's history (the
``phyllocian'' era) are found in the oldest terrains; sulfates were
formed in a second era (the ``theiikian'' era) in an acidic environment.
Beginning about 3.5 billion years ago, the last era (the ``siderikian'')
is dominated by the formation of anhydrous ferric oxides in a slow
superficial weathering, without liquid water playing a major role across
the planet.
}},
  doi = {10.1126/science.1122659},
  adsurl = {http://adsabs.harvard.edu/abs/2006Sci...312..400B},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2006Sci...311..368F,
  author = {{Forget}, F. and {Haberle}, R.~M. and {Montmessin}, F. and {Levrard}, B. and 
	{Head}, J.~W.},
  title = {{Formation of Glaciers on Mars by Atmospheric Precipitation at High Obliquity}},
  journal = {Science},
  year = 2006,
  volume = 311,
  pages = {368-371},
  abstract = {{Surface conditions on Mars are currently cold and dry, with water ice
unstable on the surface except near the poles. However, geologically
recent glacierlike landforms have been identified in the tropics and the
midlatitudes of Mars. The ice has been proposed to originate from either
a subsurface reservoir or the atmosphere. We present high-resolution
climate simulations performed with a model designed to simulate the
present-day Mars water cycle but assuming a 45{\deg} obliquity as
experienced by Mars a few million years ago. The model predicts ice
accumulation in regions where glacier landforms are observed, on the
western flanks of the great volcanoes and in the eastern Hellas region.
This agreement points to an atmospheric origin for the ice and reveals
how precipitation could have formed glaciers on Mars.
}},
  doi = {10.1126/science.1120335},
  adsurl = {http://adsabs.harvard.edu/abs/2006Sci...311..368F},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2006Sci...311..201R,
  author = {{Rannou}, P. and {Montmessin}, F. and {Hourdin}, F. and {Lebonnois}, S.
	},
  title = {{The Latitudinal Distribution of Clouds on Titan}},
  journal = {Science},
  year = 2006,
  volume = 311,
  pages = {201-205},
  abstract = {{Clouds have been observed recently on Titan, through the thick haze,
using near-infrared spectroscopy and images near the south pole and in
temperate regions near 40{\deg}S. Recent telescope and Cassini orbiter
observations are now providing an insight into cloud climatology. To
study clouds, we have developed a general circulation model of Titan
that includes cloud microphysics. We identify and explain the formation
of several types of ethane and methane clouds, including south polar
clouds and sporadic clouds in temperate regions and especially at
40{\deg} in the summer hemisphere. The locations, frequencies, and
composition of these cloud types are essentially explained by the
large-scale circulation.
}},
  doi = {10.1126/science.1118424},
  adsurl = {http://adsabs.harvard.edu/abs/2006Sci...311..201R},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}