@comment{{This file has been generated by bib2bib 1.97}}
@comment{{Command line: bib2bib --quiet -c year=2004 -c $type="ARTICLE" -oc pub2004.txt -ob pub2004.bib}}
  author = {{Hourdin}, F. and {Lebonnois}, S. and {Luz}, D. and {Rannou}, P.
  title = {{Titan's stratospheric composition driven by condensation and dynamics}},
  journal = {Journal of Geophysical Research (Planets)},
  keywords = {Planetology: Fluid Planets: Atmospheres-structure and dynamics, Planetology: Fluid Planets: Atmospheres-composition and chemistry, Planetology: Solar System Objects: Saturnian satellites},
  year = 2004,
  volume = 109,
  number = e18,
  eid = {E12005},
  pages = {12005},
  abstract = {{Atmospheric transport of chemical compounds and organic haze in the
stratosphere of Titan is investigated with an axisymmetric general
circulation model. It has been shown previously that the meridional
circulation, dominated by global Hadley cells, is responsible both for
the creation of an intense stratospheric zonal flow and for the
accumulation of chemical compounds and haze in high latitudes. The
modified composition in turn intensifies the meridional circulation and
equator-to-pole thermal contrasts. This paper analyzes in detail the
transport processes responsible for the observed vertical and
latitudinal variations of atmospheric composition. It is shown that the
competition between rapid sinking of air from the upper stratosphere in
the winter polar vortex and latitudinal mixing by barotropic planetary
waves (parameterized in the model) controls the vertical gradient of
chemical compounds. The magnitude of polar enrichment (of a factor 1.4
to 20 depending on the particular species) with respect to low latitudes
is mostly controlled by the way the meridional advection increases the
concentrations of chemical compounds in the clean air which is rising
from the troposphere, where most of the chemical compounds are removed
by condensation (the temperature at the tropopause being close to 70 K).
The agreement between the observed and simulated contrasts provides an
indirect but strong validation of the simulated dynamics, thus
confirming the explanation put forward for atmospheric superrotation. It
is shown also that by measuring the atmospheric composition, the
Cassini-Huygens mission will provide a strong constraint about Titan's
atmospheric circulation.
  doi = {10.1029/2004JE002282},
  adsurl = {},
  localpdf = {REF/2004JGRE..10912005H.pdf},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Encrenaz}, T. and {Bézard}, B. and {Greathouse}, T.~K. and 
	{Richter}, M.~J. and {Lacy}, J.~H. and {Atreya}, S.~K. and {Wong}, A.~S. and 
	{Lebonnois}, S. and {Lefèvre}, F. and {Forget}, F.},
  title = {{Hydrogen peroxide on Mars: evidence for spatial and seasonal variations}},
  journal = {\icarus},
  keywords = {Mars, atmosphere, composition, Infrared observations, Photochemistry},
  year = 2004,
  volume = 170,
  pages = {424-429},
  abstract = {{Hydrogen peroxide (H $_{2}$O $_{2}$) has been suggested as a
possible oxidizer of the martian surface. Photochemical models predict a
mean column density in the range of 10 $^{15}$-10 $^{16}$ cm
$^{-2}$. However, a stringent upper limit of the H $_{2}$O
$_{2}$ abundance on Mars (9{\times}10 $^{14}$ cm
$^{-2}$) was derived in February 2001 from ground-based infrared
spectroscopy, at a time corresponding to a maximum water vapor abundance
in the northern summer (30 pr. {$\mu$}m, Ls=112{\deg}). Here we report the
detection of H $_{2}$O $_{2}$ on Mars in June 2003, and its
mapping over the martian disk using the same technique, during the
southern spring ( Ls=206{\deg}) when the global water vapor abundance was
{\tilde}10 pr. {$\mu$}m. The spatial distribution of H $_{2}$O
$_{2}$ shows a maximum in the morning around the sub-solar
latitude. The mean H $_{2}$O $_{2}$ column density
(6{\times}10 $^{15}$ cm $^{-2}$) is significantly greater
than our previous upper limit, pointing to seasonal variations. Our new
result is globally consistent with the predictions of photochemical
models, and also with submillimeter ground-based measurements obtained
in September 2003 ( Ls=254{\deg}), averaged over the martian disk (Clancy
et al., 2004, Icarus 168, 116-121).
  doi = {10.1016/j.icarus.2004.05.008},
  adsurl = {},
  localpdf = {REF/2004Icar..170..424E.pdf},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Lefèvre}, F. and {Lebonnois}, S. and {Montmessin}, F. and 
	{Forget}, F.},
  title = {{Three-dimensional modeling of ozone on Mars}},
  journal = {Journal of Geophysical Research (Planets)},
  keywords = {Atmospheric Composition and Structure: Middle atmosphere-constituent transport and chemistry (3334), Planetology: Solid Surface Planets: Atmospheres-composition and chemistry, Planetology: Solar System Objects: Mars},
  year = 2004,
  volume = 109,
  eid = {E07004},
  pages = {7004},
  abstract = {{We present the first three-dimensional model simulations of ozone on
Mars. The model couples a state-of-the-art gas-phase photochemical
package to the general circulation model developed at Laboratoire de
Météorologie Dynamique (LMD). The results do not
contradict the classical picture of a global anticorrelation between the
ozone (O$_{3}$) and water vapor columns. However, the quantitative
approach shows significant departures from this relationship, related to
substantial orbital variations in the O$_{3}$ vertical
distribution. Over the period L$_{s}$ = 180{\deg}-330{\deg},
low-latitude to midlatitude O$_{3}$ is essentially confined below
20 km, has a weak diurnal cycle, and is largely modulated by topography.
During the rest of the year (L$_{s}$ = 330{\deg}-180{\deg}) the
model predicts the formation of an O$_{3}$ layer at 25-70 km
altitude, characterized by nighttime densities about one order of
magnitude larger than during the day. Throughout the year, high-latitude
O$_{3}$ peaks near the surface and reaches maximum integrated
amounts (\~{}40 {$\mu$}m-atm) in the winter polar vortex, with considerable
(30 to 50\%) dynamically induced day-to-day variations. The most
stringent comparison to date with O$_{3}$ observational data
reveals contrasted results. A good quantitative agreement is found in
the postperihelion period (L$_{s}$ = 290{\deg}-10{\deg}), but the
model fails to reproduce O$_{3}$ columns as large as those
measured near aphelion (L$_{s}$ = 61{\deg}-67{\deg}). Current
uncertainties in absorption cross sections and gas-phase kinetics data
do not seem to provide credible explanations to explain this
discrepancy, which may suggest the existence of heterogeneous processes.
  doi = {10.1029/2004JE002268},
  adsurl = {},
  localpdf = {REF/2004JGRE..109.7004L.pdf},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}