@comment{{This file has been generated by bib2bib 1.94}}
@comment{{Command line: /usr/bin/bib2bib --quiet -c 'not journal:"Discussions"' -c year=2013 -c $type="ARTICLE" -oc pub2013.txt -ob pub2013.bib}}
  author = {{Leconte}, J. and {Forget}, F. and {Charnay}, B. and {Wordsworth}, R. and 
	{Pottier}, A.},
  title = {{Increased insolation threshold for runaway greenhouse processes on Earth-like planets}},
  journal = {\nat},
  archiveprefix = {arXiv},
  eprint = {1312.3337},
  primaryclass = {astro-ph.EP},
  year = 2013,
  volume = 504,
  pages = {268-271},
  abstract = {{The increase in solar luminosity over geological timescales should warm
the Earth's climate, increasing water evaporation, which will in turn
enhance the atmospheric greenhouse effect. Above a certain critical
insolation, this destabilizing greenhouse feedback can `run away' until
the oceans have completely evaporated. Through increases in
stratospheric humidity, warming may also cause evaporative loss of the
oceans to space before the runaway greenhouse state occurs. The critical
insolation thresholds for these processes, however, remain uncertain
because they have so far been evaluated using one-dimensional models
that cannot account for the dynamical and cloud feedback effects that
are key stabilizing features of the Earth's climate. Here we use a
three-dimensional global climate model to show that the insolation
threshold for the runaway greenhouse state to occur is about 375 W
m$^{-2}$, which is significantly higher than previously thought.
Our model is specifically developed to quantify the climate response of
Earth-like planets to increased insolation in hot and extremely moist
atmospheres. In contrast with previous studies, we find that clouds have
a destabilizing feedback effect on the long-term warming. However,
subsident, unsaturated regions created by the Hadley circulation have a
stabilizing effect that is strong enough to shift the runaway greenhouse
limit to higher values of insolation than are inferred from
one-dimensional models. Furthermore, because of wavelength-dependent
radiative effects, the stratosphere remains sufficiently cold and dry to
hamper the escape of atmospheric water, even at large fluxes. This has
strong implications for the possibility of liquid water existing on
Venus early in its history, and extends the size of the habitable zone
around other stars.
  doi = {10.1038/nature12827},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Pilorget}, C. and {Edwards}, C.~S. and {Ehlmann}, B.~L. and 
	{Forget}, F. and {Millour}, E.},
  title = {{Material ejection by the cold jets and temperature evolution of the south seasonal polar cap of Mars from THEMIS/CRISM observations and implications for surface properties}},
  journal = {Journal of Geophysical Research (Planets)},
  keywords = {Mars, ice, climate, surface temperature},
  year = 2013,
  volume = 118,
  pages = {2520-2536},
  abstract = {{As the seasonal CO$_{2}$ ice polar caps of Mars retreat during
spring, dark spots appear on the ice in some specific regions. These
features are thought to result from basal sublimation of the transparent
CO$_{2}$ ice followed by ejection of regolith-type material, which
then covers the ice. We have used Compact Reconnaissance Imaging
Spectrometer for Mars (CRISM) reflectance data, Thermal Emission Imaging
System (THEMIS) visible images, and THEMIS-derived temperature
retrievals along with a thermal numerical model to constrain the
physical and compositional characteristics of the seasonal cap for
several areas exhibiting dark spots at both high spatial and temporal
resolutions. Data analysis suggests an active period of material
ejection (before solar longitude (Ls) 200), accumulation around the
ejection points, and spreading of part of the ejected material over the
whole area, followed by a period where no significant amount of material
is ejected, followed by complete defrosting ({\ap} Ls 245). Dark material
thickness on top of the CO$_{2}$ ice is estimated to range from a
few hundreds of microns to a few millimeters in the warmest spots, based
on numerical modeling combined with the observed temperature evolution.
The nature of the venting process and the amount of material that is
moved lead to the conclusion that it could have an important impact on
the surface physical properties.
  doi = {10.1002/2013JE004513},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Gonz{\'a}lez-Galindo}, F. and {Chaufray}, J.-Y. and {L{\'o}pez-Valverde}, M.~A. and 
	{Gilli}, G. and {Forget}, F. and {Leblanc}, F. and {Modolo}, R. and 
	{Hess}, S. and {Yagi}, M.},
  title = {{Three-dimensional Martian ionosphere model: I. The photochemical ionosphere below 180 km}},
  journal = {Journal of Geophysical Research (Planets)},
  keywords = {Mars, ionosphere, model, photochemistry},
  year = 2013,
  volume = 118,
  pages = {2105-2123},
  abstract = {{We describe the Mars ionosphere with unprecedented detail in 3-D, as
simulated by a Mars general circulation model (the Laboratoire de
Météorologie Dynamique Mars GCM), and compare it with
recent measurements. The model includes a number of recent extensions
and improvements. Different simulations for a full Martian year have
been performed. The electron density at the main ionospheric peak is
shown to vary with the Sun-Mars distance and with the solar variability,
both in the long-term (11 year solar cycle) and on shorter temporal
scales (solar rotation). The main electronic peak is shown to be located
at the same pressure level during all the Martian year. As a
consequence, its altitude varies with latitude, local time, and season
according to the natural expansions and fluctuations of the neutral
atmosphere, in agreement with previous models. The model predicts a
nighttime ionosphere due only to photochemistry. The simulated
ionosphere close to the evening terminator is in agreement with
observations. No effort has been made to explain the patchy ionosphere
observed in the deep nightside. We have compared the modeled ionosphere
with Mars Global Surveyor and Mars Advanced Radar for Subsurface and
Ionosphere Sounding data. The model reproduces the solar zenith angle
variability of the electron density and the altitude of the peak,
although it underestimates the electron density at the main peak by
about 20\%. The electron density at the secondary peak is strongly
underestimated by the model, probably due to a very crude representation
of the X-ray solar flux. This is one of the aspects that needs a
revision in future versions of the model.
  doi = {10.1002/jgre.20150},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Marcq}, E. and {Lebonnois}, S.},
  title = {{Simulations of the latitudinal variability of CO-like and OCS-like passive tracers below the clouds of Venus using the Laboratoire de Météorologie Dynamique GCM}},
  journal = {Journal of Geophysical Research (Planets)},
  keywords = {Venus, atmosphere, general circulation model, passive tracers, carbon monoxide, carbonyl sulfide},
  year = 2013,
  volume = 118,
  pages = {1983-1990},
  abstract = {{The lower atmosphere of Venus below the clouds is a transitional region
between the relatively calm lowermost scale height and the superrotating
atmosphere in the cloud region and above. Any observational constraint
is then welcome to help in the development of general circulation models
of Venus, a difficult task considering the thickness of its atmosphere.
Starting from a state-of-the-art 3-D Venus General Circulation Model
(GCM), we have included passive tracers in order to investigate the
latitudinal variability of two minor gaseous species, carbonyl sulfide
(OCS) and carbon monoxide (CO), whose vertical profiles and mixing
ratios are known to vary with latitude between 30 and 40km. The
relaxation to chemical equilibrium is crudely parametrized through a
vertically uniform time scale {$\tau$}. A satisfactory agreement with
available observations is obtained with
10$^{8}$s{\lsim}{$\tau$}$_{CO}${\lsim}5{\middot}10$^{8}$ s
and 10$^{7}$s{\lsim}{$\tau$}$_{OCS}${\lsim}10$^{8}$ s.
These results, in addition to validating the general circulation below
the clouds, are also helpful in characterizing the chemical kinetics of
Venus' atmosphere. This complements the much more sophisticated chemical
models which focus more on thermodynamical equilibrium.
  doi = {10.1002/jgre.20146},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Monteil}, G. and {Houweling}, S. and {Butz}, A. and {Guerlet}, S. and 
	{Schepers}, D. and {Hasekamp}, O. and {Frankenberg}, C. and 
	{Scheepmaker}, R. and {Aben}, I. and {R{\"o}ckmann}, T.},
  journal = {Journal of Geophysical Research (Atmospheres)},
  keywords = {methane, GOSAT, SCIAMACHY, inverse modelling},
  year = 2013,
  volume = 118,
  number = d17,
  pages = {11},
  abstract = {{Over the past decade the development of Scanning Imaging Absorption
Spectrometer for Atmospheric Chartography (SCIAMACHY) retrievals has
increased the interest in the use of satellite measurements for studying
the global sources and sinks of methane. Meanwhile, measurements are
becoming available from the more advanced Greenhouse Gases Observing
Satellite (GOSAT). The aim of this study is to investigate the
application of GOSAT retrievals to inverse modeling, for which we make
use of the TM5-4DVAR inverse modeling framework. Inverse modeling
calculations are performed using data from two different retrieval
approaches: a full physics and a lightpath proxy ratio method. The
performance of these inversions is analyzed in comparison with
inversions using SCIAMACHY retrievals and measurements from the National
Oceanic and Atmospheric Administration-Earth System Research Laboratory
flask-sampling network. In addition, we compare the inversion results
against independent surface, aircraft, and total-column measurements.
Inversions with GOSAT data show good agreement with surface
measurements, whereas for SCIAMACHY a similar performance can only be
achieved after significant bias corrections. Some inconsistencies
between surface and total-column methane remain in the Southern
Hemisphere. However, comparisons with measurements from the Total Column
Carbon Observing Network in situ Fourier transform spectrometer network
indicate that those may be caused by systematic model errors rather than
by shortcomings in the GOSAT retrievals. The global patterns of methane
emissions derived from SCIAMACHY (with bias correction) and GOSAT
retrievals are in remarkable agreement and allow an increased resolution
of tropical emissions. The satellite inversions increase tropical
methane emission by 30 to 60 TgCH$_{4}$/yr compared to initial a
priori estimates, partly counterbalanced by reductions in emissions at
midlatitudes to high latitudes.
  doi = {10.1002/2013JD019760},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Smith}, I.~B. and {Holt}, J.~W. and {Spiga}, A. and {Howard}, A.~D. and 
	{Parker}, G.},
  title = {{The spiral troughs of Mars as cyclic steps}},
  journal = {Journal of Geophysical Research (Planets)},
  keywords = {Mars, ice, polar, Aeolian, troughs, spiral},
  year = 2013,
  volume = 118,
  pages = {1835-1857},
  abstract = {{combine observations of stratigraphy, morphology, and atmospheric
processes to relate the spiral troughs on Mars' polar layered deposits
to a class of features known as cyclic steps. Cyclic steps are
quasi-stable, repeating, and upstream-migrating bed forms that have been
studied in terrestrial and submarine environments. The repeating pattern
is bounded by hydraulic jumps, which act to stabilize the form. We use
radar stratigraphy from the Shallow Radar instrument on Mars
Reconnaissance Orbiter to examine trough evolution and constrain lateral
transport. We examine visible images from the Thermal Emission Imaging
System and observe low-altitude clouds that we interpret to be the
result of katabatic jumps, i.e., the Aeolian counterpart of hydraulic
jumps in open channel flow. We then devise a theoretical framework for
understanding the origin of the spiral troughs that agree with 10
criteria that should be explained for any scenario to satisfactorily
model the spiral troughs. Finally, we use Froude and geometrical
analysis to estimate the rate of upstream migration caused by katabatic
winds for the spiral troughs.
  doi = {10.1002/jgre.20142},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Charnay}, B. and {Forget}, F. and {Wordsworth}, R. and {Leconte}, J. and 
	{Millour}, E. and {Codron}, F. and {Spiga}, A.},
  title = {{Exploring the faint young Sun problem and the possible climates of the Archean Earth with a 3-D GCM}},
  journal = {Journal of Geophysical Research (Atmospheres)},
  archiveprefix = {arXiv},
  eprint = {1310.4286},
  primaryclass = {astro-ph.EP},
  keywords = {early Earth, Archean, paleo-climates},
  year = 2013,
  volume = 118,
  number = d17,
  pages = {10},
  abstract = {{Different solutions have been proposed to solve the ``faint young Sun
problem,'' defined by the fact that the Earth was not fully frozen during
the Archean despite the fainter Sun. Most previous studies were
performed with simple 1-D radiative convective models and did not
account well for the clouds and ice-albedo feedback or the atmospheric
and oceanic transport of energy. We apply a global climate model (GCM)
to test the different solutions to the faint young Sun problem. We
explore the effect of greenhouse gases (CO$_{2}$ and
CH$_{4}$), atmospheric pressure, cloud droplet size, land
distribution, and Earth's rotation rate. We show that neglecting organic
haze, 100 mbar of CO$_{2}$ with 2 mbar of CH$_{4}$ at 3.8 Ga
and 10 mbar of CO$_{2}$ with 2 mbar of CH$_{4}$ at 2.5 Ga
allow a temperate climate (mean surface temperature between 10{\deg}C and
20{\deg}C). Such amounts of greenhouse gases remain consistent with the
geological data. Removing continents produces a warming lower than
+4{\deg}C. The effect of rotation rate is even more limited. Larger
droplets (radii of 17 {$\mu$}m versus 12 {$\mu$}m) and a doubling of the
atmospheric pressure produce a similar warming of around +7{\deg}C. In
our model, ice-free water belts can be maintained up to 25{\deg}N/S with
less than 1 mbar of CO$_{2}$ and no methane. An interesting cloud
feedback appears above cold oceans, stopping the glaciation. Such a
resistance against full glaciation tends to strongly mitigate the faint
young Sun problem.
  doi = {10.1002/jgrd.50808},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Butz}, A. and {Guerlet}, S. and {Hasekamp}, O.~P. and {Kuze}, A. and 
	{Suto}, H.},
  title = {{Using ocean-glint scattered sunlight as a diagnostic tool for satellite remote sensing of greenhouse gases}},
  journal = {Atmospheric Measurement Techniques},
  year = 2013,
  volume = 6,
  pages = {2509-2520},
  abstract = {{Spectroscopic measurements of sunlight backscattered by the Earth's
surface is a technique widely used for remote sensing of atmospheric
constituent concentrations from space. Thereby, remote sensing of
greenhouse gases poses particularly challenging accuracy requirements
for instrumentation and retrieval algorithms which, in general, suffer
from various error sources. Here, we investigate a method that helps
disentangle sources of error for observations of sunlight backscattered
from the glint spot on the ocean surface. The method exploits the
backscattering characteristics of the ocean surface, which is bright for
glint geometry but dark for off-glint angles. This property allows for
identifying a set of clean scenes where light scattering due to
particles in the atmosphere is negligible such that uncertain knowledge
of the lightpath can be excluded as a source of error. We apply the
method to more than 3 yr of ocean-glint measurements by the Thermal And
Near infrared Sensor for carbon Observation (TANSO) Fourier Transform
Spectrometer (FTS) onboard the Greenhouse Gases Observing Satellite
(GOSAT), which aims at measuring carbon dioxide (CO$_{2}$) and
methane (CH$_{4}$) concentrations. The proposed method is able to
clearly monitor recent improvements in the instrument calibration of the
oxygen (O$_{2}$) A-band channel and suggests some residual
uncertainty in our knowledge about the instrument. We further assess the
consistency of CO$_{2}$ retrievals from several absorption bands
between 6400 cm$^{-1}$ (1565 nm) and 4800 cm$^{-1}$ (2100
nm) and find that the absorption bands commonly used for monitoring of
CO$_{2}$ dry air mole fractions from GOSAT allow for consistency
better than 1.5 ppm. Usage of other bands reveals significant
inconsistency among retrieved CO$_{2}$ concentrations pointing at
inconsistency of spectroscopic parameters.
  doi = {10.5194/amt-6-2509-2013},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Basu}, S. and {Guerlet}, S. and {Butz}, A. and {Houweling}, S. and 
	{Hasekamp}, O. and {Aben}, I. and {Krummel}, P. and {Steele}, P. and 
	{Langenfelds}, R. and {Torn}, M. and {Biraud}, S. and {Stephens}, B. and 
	{Andrews}, A. and {Worthy}, D.},
  title = {{Global CO$_{2}$ fluxes estimated from GOSAT retrievals of total column CO$_{2}$}},
  journal = {Atmospheric Chemistry \& Physics},
  year = 2013,
  volume = 13,
  pages = {8695-8717},
  abstract = {{We present one of the first estimates of the global distribution of
CO$_{2}$ surface fluxes using total column CO$_{2}$
measurements retrieved by the SRON-KIT RemoTeC algorithm from the
Greenhouse gases Observing SATellite (GOSAT). We derive optimized fluxes
from June 2009 to December 2010. We estimate fluxes from surface
CO$_{2}$ measurements to use as baselines for comparing GOSAT
data-derived fluxes. Assimilating only GOSAT data, we can reproduce the
observed CO$_{2}$ time series at surface and TCCON sites in the
tropics and the northern extra-tropics. In contrast, in the southern
extra-tropics GOSAT X$_{CO2}$ leads to enhanced
seasonal cycle amplitudes compared to independent measurements, and we
identify it as the result of a land-sea bias in our GOSAT
X$_{CO2}$ retrievals. A bias correction in the form of
a global offset between GOSAT land and sea pixels in a joint inversion
of satellite and surface measurements of CO$_{2}$ yields plausible
global flux estimates which are more tightly constrained than in an
inversion using surface CO$_{2}$ data alone. We show that
assimilating the bias-corrected GOSAT data on top of surface
CO$_{2}$ data (a) reduces the estimated global land sink of
CO$_{2}$, and (b) shifts the terrestrial net uptake of carbon from
the tropics to the extra-tropics. It is concluded that while GOSAT total
column CO$_{2}$ provide useful constraints for source-sink
inversions, small spatiotemporal biases - beyond what can be detected
using current validation techniques - have serious consequences for
optimized fluxes, even aggregated over continental scales.
  doi = {10.5194/acp-13-8695-2013},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Clifford}, S.~M. and {Yoshikawa}, K. and {Byrne}, S. and {Durham}, W. and 
	{Fisher}, D. and {Forget}, F. and {Hecht}, M. and {Smith}, P. and 
	{Tamppari}, L. and {Titus}, T. and {Zurek}, R.},
  title = {{Introduction to the fifth Mars Polar Science special issue: Key questions, needed observations, and recommended investigations}},
  journal = {\icarus},
  year = 2013,
  volume = 225,
  pages = {864-868},
  doi = {10.1016/j.icarus.2013.04.005},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Scanlon}, K.~E. and {Head}, J.~W. and {Madeleine}, J.-B. and 
	{Wordsworth}, R.~D. and {Forget}, F.},
  title = {{Orographic precipitation in valley network headwaters: Constraints on the ancient Martian atmosphere}},
  journal = {\grl},
  keywords = {orographic precipitation, valley networks, Noachian, atmospheric pressure},
  year = 2013,
  volume = 40,
  pages = {4182-4187},
  abstract = {{We examine the Martian valley networks in the framework of topographic
influences on precipitation. We use an analytical model and the
Laboratoire de Météorologie Dynamique (LMD) early Mars
global circulation model (GCM) to explore the local-scale distribution
of orographically forced precipitation as a function of atmospheric
pressure. In simulations with 500 mbar and 1 bar CO$_{2}$
atmospheres, orographic lifting results in enhanced snowfall upslope of
the observed valley network tributaries. Our framework also suggests
that a 2 bar atmosphere cannot create the observed valley pattern at the
highest-relief valley network, Warrego Valles. As in previous work, the
GCM does not generate temperatures warm enough for rain or significant
snowmelt in the highlands with CO$_{2}$ greenhouse warming alone.
Thus while transient periods of unusual warming are still required to
melt the deposits and carve the valleys, our model predicts snow
deposition in the correct locations.
  doi = {10.1002/grl.50687},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Cola{\"i}tis}, A. and {Spiga}, A. and {Hourdin}, F. and {Rio}, C. and 
	{Forget}, F. and {Millour}, E.},
  title = {{A thermal plume model for the Martian convective boundary layer}},
  journal = {Journal of Geophysical Research (Planets)},
  archiveprefix = {arXiv},
  eprint = {1306.6215},
  primaryclass = {},
  keywords = {Mars, atmosphere, convection, boundary layer, large-eddy simulations, PBL parameterization},
  year = 2013,
  volume = 118,
  pages = {1468-1487},
  abstract = {{The Martian planetary boundary layer (PBL) is a crucial component of the
Martian climate system. Global climate models (GCMs) and mesoscale
models (MMs) lack the resolution to predict PBL mixing which is
therefore parameterized. Here we propose to adapt the ``thermal plume''
model, recently developed for Earth climate modeling, to Martian GCMs,
MMs, and single-column models. The aim of this physically based
parameterization is to represent the effect of organized turbulent
structures (updrafts and downdrafts) on the daytime PBL transport, as it
is resolved in large-eddy simulations (LESs). We find that the
terrestrial thermal plume model needs to be modified to satisfyingly
account for deep turbulent plumes found in the Martian convective PBL.
Our Martian thermal plume model qualitatively and quantitatively
reproduces the thermal structure of the daytime PBL on Mars:
superadiabatic near-surface layer, mixing layer, and overshoot region at
PBL top. This model is coupled to surface layer parameterizations taking
into account stability and turbulent gustiness to calculate
surface-atmosphere fluxes. Those new parameterizations for the surface
and mixed layers are validated against near-surface lander measurements.
Using a thermal plume model moreover enables a first-order estimation of
key turbulent quantities (e.g., PBL height and convective plume
velocity) in Martian GCMs and MMs without having to run costly LESs.
  doi = {10.1002/jgre.20104},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Forget}, F.},
  title = {{On the probability of habitable planets}},
  journal = {International Journal of Astrobiology},
  archiveprefix = {arXiv},
  eprint = {1212.0113},
  primaryclass = {astro-ph.EP},
  keywords = {exoplanets, life forms, liquid water, climate},
  year = 2013,
  volume = 12,
  pages = {177-185},
  abstract = {{In the past 15 years, astronomers have revealed that a significant
fraction of the stars should harbour planets and that it is likely that
terrestrial planets are abundant in our galaxy. Among these planets, how
many are habitable, i.e. suitable for life and its evolution? These
questions have been discussed for years and we are slowly making
progress. Liquid water remains the key criterion for habitability. It
can exist in the interior of a variety of planetary bodies, but it is
usually assumed that liquid water at the surface interacting with rocks
and light is necessary for emergence of a life able to modify its
environment and evolve. The first key issue is thus to understand the
climatic conditions allowing surface liquid water assuming a suitable
atmosphere. These have been studied with global mean one-dimensional
(1D) models which have defined the `classical habitable zone', the range
of orbital distances within which worlds can maintain liquid water on
their surfaces (Kasting et al. 1993). A new generation of 3D climate
models based on universal equations and tested on bodies in the solar
system are now available to explore with accuracy climate regimes that
could locally allow liquid water. The second key issue is now to better
understand the processes which control the composition and the evolution
of the atmospheres of exoplanets, and in particular the geophysical
feedbacks that seem to be necessary to maintain a continuously habitable
climate. From that point of view, it is not impossible that the Earth's
case may be special and uncommon.
  doi = {10.1017/S1473550413000128},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Parazoo}, N.~C. and {Bowman}, K. and {Frankenberg}, C. and 
	{Lee}, J.-E. and {Fisher}, J.~B. and {Worden}, J. and {Jones}, D.~B.~A. and 
	{Berry}, J. and {Collatz}, G.~J. and {Baker}, I.~T. and {Jung}, M. and 
	{Liu}, J. and {Osterman}, G. and {O'Dell}, C. and {Sparks}, A. and 
	{Butz}, A. and {Guerlet}, S. and {Yoshida}, Y. and {Chen}, H. and 
	{Gerbig}, C.},
  title = {{Interpreting seasonal changes in the carbon balance of southern Amazonia using measurements of XCO$_{2}$ and chlorophyll fluorescence from GOSAT}},
  journal = {\grl},
  keywords = {carbon cycle, amazon, satellite remote sensing, GOSAT, chlorophyll fluorescence, biomass burning},
  year = 2013,
  volume = 40,
  pages = {2829-2833},
  abstract = {{Amazon forests exert a major influence on the global carbon cycle, but
quantifying the impact is complicated by diverse landscapes and sparse
data. Here we examine seasonal carbon balance in southern Amazonia using
new measurements of column-averaged dry air mole fraction of
CO$_{2}$ (XCO$_{2}$) and solar induced chlorophyll
fluorescence (SIF) from the Greenhouse Gases Observing Satellite (GOSAT)
from July 2009 to December 2010. SIF, which reflects gross primary
production (GPP), is used to disentangle the photosynthetic component of
land-atmosphere carbon exchange. We find that tropical transitional
forests in southern Amazonia exhibit a pattern of low XCO$_{2}$
during the wet season and high XCO$_{2}$ in the dry season that is
robust to retrieval methodology and with seasonal amplitude double that
of cerrado ecosystems to the east (4 ppm versus 2 ppm), including
enhanced dilution of 2.5 ppm in the wet season. Concomitant measurements
of SIF, which are inversely correlated with XCO$_{2}$ in southern
Amazonia (r = -0.53, p $\lt$ 0.001), indicate that the enhanced
variability is driven by seasonal changes in GPP due to coupling of
strong vertical mixing with seasonal changes in underlying carbon
exchange. This finding is supported by forward simulations of the
Goddard Chemistry Transport Model (GEOS-Chem) which show that local
carbon uptake in the wet season and loss in the dry season due to
emissions by ecosystem respiration and biomass burning produces best
agreement with observed XCO$_{2}$. We conclude that GOSAT provides
critical measurements of carbon exchange in southern Amazonia, but more
samples are needed to examine moist Amazon forests farther north.
  doi = {10.1002/grl.50452},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Leconte}, J. and {Forget}, F. and {Charnay}, B. and {Wordsworth}, R. and 
	{Selsis}, F. and {Millour}, E. and {Spiga}, A.},
  title = {{3D climate modeling of close-in land planets: Circulation patterns, climate moist bistability, and habitability}},
  journal = {\aap},
  archiveprefix = {arXiv},
  eprint = {1303.7079},
  primaryclass = {astro-ph.EP},
  keywords = {planets and satellites: general, planets and satellites: atmospheres, planets and satellites: physical evolution, planet-star interactions},
  year = 2013,
  volume = 554,
  eid = {A69},
  pages = {A69},
  abstract = {{The inner edge of the classical habitable zone is often defined by the
critical flux needed to trigger the runaway greenhouse instability. This
1D notion of a critical flux, however, may not be all that relevant for
inhomogeneously irradiated planets, or when the water content is limited
(land planets). Based on results from our 3D global climate model, we
present general features of the climate and large-scale circulation on
close-in terrestrial planets. We find that the circulation pattern can
shift from super-rotation to stellar/anti stellar circulation when the
equatorial Rossby deformation radius significantly exceeds the planetary
radius, changing the redistribution properties of the atmosphere. Using
analytical and numerical arguments, we also demonstrate the presence of
systematic biases among mean surface temperatures and among temperature
profiles predicted from either 1D or 3D simulations. After including a
complete modeling of the water cycle, we further demonstrate that two
stable climate regimes can exist for land planets closer than the inner
edge of the classical habitable zone. One is the classical runaway state
where all the water is vaporized, and the other is a collapsed state
where water is captured in permanent cold traps. We identify this
``moist'' bistability as the result of a competition between the
greenhouse effect of water vapor and its condensation on the night side
or near the poles, highlighting the dynamical nature of the runaway
greenhouse effect. We also present synthetic spectra showing the
observable signature of these two states. Taking the example of two
prototype planets in this regime, namely Gl 581 c and HD 85512 b, we
argue that depending on the rate of water delivery and atmospheric
escape during the life of these planets, they could accumulate a
significant amount of water ice at their surface. If such a thick ice
cap is present, various physical mechanisms observed on Earth (e.g.,
gravity driven ice flows, geothermal flux) should come into play to
produce long-lived liquid water at the edge and/or bottom of the ice
cap. Consequently, the habitability of planets at smaller orbital
distance than the inner edge of the classical habitable zone cannot be
ruled out. Transiting planets in this regime represent promising targets
for upcoming exoplanet characterization observatories, such as EChO and
  doi = {10.1051/0004-6361/201321042},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Clancy}, R.~T. and {Sandor}, B.~J. and {Wolff}, M.~J. and {Smith}, M.~D. and 
	{LefèVre}, F. and {Madeleine}, J.-B. and {Forget}, F. and 
	{Murchie}, S.~L. and {Seelos}, F.~P. and {Seelos}, K.~D. and 
	{Nair}, H. and {Toigo}, A.~D. and {Humm}, D. and {Kass}, D.~M. and 
	{Kleinb{\"o}Hl}, A. and {Heavens}, N.},
  title = {{Correction to ``Extensive MRO CRISM observations of 1.27 {\micro}m O$_{2}$ airglow in Mars polar night and their comparison to MRO MCS temperature profiles and LMD GCM simulations''}},
  journal = {Journal of Geophysical Research (Planets)},
  keywords = {Correction, Mars, Nightglow, O2, Atmosphere, Photochemistry},
  year = 2013,
  volume = 118,
  pages = {1148-1154},
  doi = {10.1002/jgre.20073},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Guerlet}, S. and {Butz}, A. and {Schepers}, D. and {Basu}, S. and 
	{Hasekamp}, O.~P. and {Kuze}, A. and {Yokota}, T. and {Blavier}, J.-F. and 
	{Deutscher}, N.~M. and {Griffith}, D.~W.~T. and {Hase}, F. and 
	{Kyro}, E. and {Morino}, I. and {Sherlock}, V. and {Sussmann}, R. and 
	{Galli}, A. and {Aben}, I.},
  title = {{Impact of aerosol and thin cirrus on retrieving and validating XCO$_{2}$ from GOSAT shortwave infrared measurements}},
  journal = {Journal of Geophysical Research (Atmospheres)},
  keywords = {Remote sensing, Carbon Dioxide, GOSAT, TCCON},
  year = 2013,
  volume = 118,
  pages = {4887-4905},
  abstract = {{Inadequate treatment of aerosol scattering can be a significant source
of error when retrieving column-averaged dry-air mole fractions of
CO$_{2}$ (XCO$_{2}$) from space-based measurements of
backscattered solar shortwave radiation. We have developed a retrieval
algorithm, RemoTeC, that retrieves three aerosol parameters (amount,
size, and height) simultaneously with XCO$_{2}$. Here we evaluate
the ability of RemoTeC to account for light path modifications by
clouds, subvisual cirrus, and aerosols when retrieving XCO$_{2}$
from Greenhouse Gases Observing Satellite (GOSAT) Thermal and
Near-infrared Sensor for carbon Observation (TANSO)-Fourier Transform
Spectrometer (FTS) measurements. We first evaluate a cloud filter based
on measurements from the Cloud and Aerosol Imager and a cirrus filter
that uses radiances measured by TANSO-FTS in the 2 micron spectral
region, with strong water absorption. For the cloud-screened scenes, we
then evaluate errors due to aerosols. We find that RemoTeC is well
capable of accounting for scattering by aerosols for values of aerosol
optical thickness at 750 nm up to 0.25. While no significant correlation
of errors is found with albedo, correlations are found with retrieved
aerosol parameters. To further improve the XCO$_{2}$ accuracy, we
propose and evaluate a bias correction scheme. Measurements from 12
ground-based stations of the Total Carbon Column Observing Network
(TCCON) are used as a reference in this study. We show that spatial
colocation criteria may be relaxed using additional constraints based on
modeled XCO$_{2}$ gradients, to increase the size and diversity of
validation data and provide a more robust evaluation of GOSAT
retrievals. Global-scale validation of satellite data remains
challenging and would be improved by increasing TCCON coverage.
  doi = {10.1002/jgrd.50332},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Guerlet}, S. and {Basu}, S. and {Butz}, A. and {Krol}, M. and 
	{Hahne}, P. and {Houweling}, S. and {Hasekamp}, O.~P. and {Aben}, I.
  title = {{Reduced carbon uptake during the 2010 Northern Hemisphere summer from GOSAT}},
  journal = {\grl},
  keywords = {GOSAT, carbon dioxide, interannual variability, biosphere-atmosphere exchanges, inverse modeling},
  year = 2013,
  volume = 40,
  pages = {2378-2383},
  abstract = {{Column-averaged dry air mole fractions of carbon dioxide
(XCO$_{2}$) measured by the Greenhouse Gases Observing Satellite
(GOSAT) reveal significant interannual variation (IAV) of
CO$_{2}$uptake during the Northern Hemisphere summer between 2009
and 2010. The XCO$_{2}$drawdown in 2010 is shallower than in 2009
by 2.4 ppm and 3.0 ppm over North America and Eurasia, respectively.
Reduced carbon uptake in the summer of 2010 is most likely due to the
heat wave in Eurasia driving biospheric fluxes and fire emissions. A
joint inversion of GOSAT and surface data estimates an integrated
biospheric and fire emission anomaly in April-September of 0.89
{\plusmn}0.20  PgC over Eurasia. In contrast, inversions of surface
measurements alone fail to replicate the observed XCO$_{2}$IAV and
underestimate emission IAV over Eurasia. This shows the value of GOSAT
XCO$_{2}$in constraining the response of land-atmosphere exchange
of CO$_{2}$ to climate events.
  doi = {10.1002/grl.50402},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Spiga}, A. and {Faure}, J. and {Madeleine}, J.-B. and {M{\"a}{\"a}tt{\"a}nen}, A. and 
	{Forget}, F.},
  title = {{Rocket dust storms and detached dust layers in the Martian atmosphere}},
  journal = {Journal of Geophysical Research (Planets)},
  archiveprefix = {arXiv},
  eprint = {1208.5030},
  primaryclass = {astro-ph.EP},
  keywords = {Mars, atmosphere, mesoscale, dust, convection, storm},
  year = 2013,
  volume = 118,
  pages = {746-767},
  abstract = {{Airborne dust is the main climatic agent in the Martian environment.
Local dust storms play a key role in the dust cycle; yet their life
cycle is poorly known. Here we use mesoscale modeling that includes the
transport of radiatively active dust to predict the evolution of a local
dust storm monitored by OMEGA on board Mars Express. We show that the
evolution of this dust storm is governed by deep convective motions. The
supply of convective energy is provided by the absorption of incoming
sunlight by dust particles, rather than by latent heating as in moist
convection on Earth. We propose to use the terminology ``rocket dust
storm,'' or conio-cumulonimbus, to describe those storms in which rapid
and efficient vertical transport takes place, injecting dust particles
at high altitudes in the Martian troposphere (30-50 km). Combined to
horizontal transport by large-scale winds, rocket dust storms produce
detached layers of dust reminiscent of those observed with Mars Global
Surveyor and Mars Reconnaissance Orbiter. Since nighttime sedimentation
is less efficient than daytime convective transport, and the detached
dust layers can convect during the daytime, these layers can be stable
for several days. The peak activity of rocket dust storms is expected in
low-latitude regions at clear seasons (late northern winter to late
northern summer), which accounts for the high-altitude tropical dust
maxima unveiled by Mars Climate Sounder. Dust-driven deep convection has
strong implications for the Martian dust cycle, thermal structure,
atmospheric dynamics, cloud microphysics, chemistry, and robotic and
human exploration.
  doi = {10.1002/jgre.20046},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Maltagliati}, L. and {Montmessin}, F. and {Korablev}, O. and 
	{Fedorova}, A. and {Forget}, F. and {M{\"a}{\"a}tt{\"a}nen}, A. and 
	{Lefèvre}, F. and {Bertaux}, J.-L.},
  title = {{Annual survey of water vapor vertical distribution and water-aerosol coupling in the martian atmosphere observed by SPICAM/MEx solar occultations}},
  journal = {\icarus},
  year = 2013,
  volume = 223,
  pages = {942-962},
  abstract = {{The vertical distribution of water vapor is a very important diagnostic
to determine the physical and chemical processes that drive the martian
water cycle. Yet, very few direct measurements have been performed so
far, and our knowledge of the H$_{2}$O vertical distribution on
Mars relies on General Circulation Models (GCMs). The study presented
here follows for the first time the evolution of water vapor profile
during a martian year. 120 profiles, obtained by the SPICAM spectrometer
onboard Mars Express with the solar occultations technique, are
retrieved. They cover the northern spring-summer season and the southern
spring of Mars Year (MY) 29. The seasonal evolution of H$_{2}$O
mixing ratio vertical distribution reveals its strong dynamism,
especially during southern spring. There are significant discrepancies
with the predictions of the General Circulation Model developed at the
Laboratoire de Météorologie Dynamique (LMD-GCM). The
LMD-GCM underestimates the water vapor content in the middle atmosphere.
The measured profiles also exhibit often abrupt temporal variations and
a greater variety of shapes, with the frequent presence of detached
layers. We believe that the model underestimates the strength of the
coupling between water vapor and aerosols, whose slant optical depth
profile is obtained by SPICAM simultaneously with H$_{2}$O. The
SPICAM measurements can be grouped according to the mutual behavior of
the two profiles. Individual features are often related too. The
presence of water supersaturation and of correlated aerosol-water
detached layers highlights the role of water ice clouds as a favorable
location for the dust-water coupling. The water vapor vertical
distribution is more reactive than expected to regional perturbations,
which can propagate rapidly through the atmosphere, create abrupt water
vapor and aerosol upsurges and influence the large-scale vertical
evolution of these two constituents. This phenomenon has been observed
thrice during MY29. The martian annual water cycle revealed by the
SPICAM profiles exhibits a different behavior with respect to nadir
observations. This result suggests a generally weak connection between
the upper atmosphere and the lower atmospheric layers, to whom the nadir
measurements are most sensitive and that are not resolved by SPICAM
occultations, and hints at a significant influence of surface-atmosphere
interactions on the water cycle.
  doi = {10.1016/j.icarus.2012.12.012},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Brothers}, T.~C. and {Holt}, J.~W. and {Spiga}, A.},
  title = {{Orbital radar, imagery, and atmospheric modeling reveal an aeolian origin for Abalos Mensa, Mars}},
  journal = {\grl},
  keywords = {Mars, Abalos Mensa, aeolian, ice, deposit, SHARAD},
  year = 2013,
  volume = 40,
  pages = {1334-1339},
  abstract = {{Icy deposits surrounding Planum Boreum, Mars, contain crucial
information for deciphering paleoclimate and past geologic processes at
the martian north pole. One such deposit, Abalos Mensa, is an enigmatic
wedge of material located near the \~{} 1 km high Rupes Tenuis. Its unique
location and lobate morphology have fostered formation hypotheses that
assume either fluvial or aeolian erosion of a once-larger ice deposit.
The aeolian scenario posed previously requires impact shielding of
ancient basal unit material to provide an erosional remnant which seeds
later deposition, while the fluvial hypotheses invoke cryovolcanism
beneath the younger north polar layered deposits (NPLD) and associated
outflow to erode the adjacent chasmata. Here we combine newly available
radar sounding data, high-resolution imagery, digital elevation models,
and atmospheric modeling to examine internal structure and infer both
the mechanisms for, and timing of, Abalos Mensa formation. From this
integrative approach, we conclude that Abalos Mensa formed as a distinct
feature via atmospheric deposition following erosion of Rupes Tenuis and
grew concurrently with the rest of Planum Boreum as the NPLD
accumulated. The required processes are consistent with those observed
today: no exotic phenomena (cryovolcanism, fluvial activity, or impact
shielding) appear necessary to explain the formation of Abalos Mensa.
  doi = {10.1002/grl.50293},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Gans}, B. and {Peng}, Z. and {Carrasco}, N. and {Gauyacq}, D. and 
	{Lebonnois}, S. and {Pernot}, P.},
  title = {{Impact of a new wavelength-dependent representation of methane photolysis branching ratios on the modeling of Titan{\rsquo}s atmospheric photochemistry}},
  journal = {\icarus},
  year = 2013,
  volume = 223,
  pages = {330-343},
  abstract = {{A new wavelength-dependent model for CH$_{4}$ photolysis branching
ratios is proposed, based on the values measured recently by Gans et al.
(Gans, B. et al. [2011]. Phys. Chem. Chem. Phys. 13, 8140-8152). We
quantify the impact of this representation on the predictions of a
photochemical model of Titan{\rsquo}s atmosphere, on their precision, and
compare to earlier representations. Although the observed effects on the
mole fraction of the species are small (never larger than 50\%), it is
possible to draw some recommendations for further studies: (i) the
Ly-{$\alpha$} branching ratios of Wang et al. (Wang, J.H. et al. [2000]. J.
Chem. Phys. 113, 4146-4152) used in recent models overestimate the
CH$_{2}$:CH$_{3}$ ratio, a factor to which a lot of species
are sensitive; (ii) the description of out-of-Ly-{$\alpha$} branching
ratios by the {\ldquo}100\% CH$_{3}${\rdquo} scenario has to be
avoided, as it can bias significantly the mole fractions of some
important species (C$_{3}$H$_{8}$); and (iii) complementary
experimental data in the 130-140 nm range would be useful to constrain
the models in the Ly-{$\alpha$} deprived 500-700 km altitude range.
  doi = {10.1016/j.icarus.2012.11.024},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Kerber}, L. and {Forget}, F. and {Madeleine}, J.-B. and {Wordsworth}, R. and 
	{Head}, J.~W. and {Wilson}, L.},
  title = {{The effect of atmospheric pressure on the dispersal of pyroclasts from martian volcanoes}},
  journal = {\icarus},
  year = 2013,
  volume = 223,
  pages = {149-156},
  abstract = {{A planetary global circulation model developed by the Laboratoire de
Météorologie Dynamique (LMD) was used to simulate
explosive eruptions of ancient martian volcanoes into paleo-atmospheres
with higher atmospheric pressures than that of present-day Mars.
Atmospheric pressures in the model were varied between 50 mbar and 2
bars. In this way it was possible to investigate the sensitivity of the
volcanic plume dispersal model to atmospheric pressure. It was
determined that the model has a sensitivity to pressure that is similar
to its sensitivity to other atmospheric parameters such as planetary
obliquity and season of eruption. Higher pressure atmospheres allow
volcanic plumes to convect to higher levels, meaning that volcanic
pyroclasts have further to fall through the atmosphere. Changes in
atmospheric circulation due to pressure cause pyroclasts to be dispersed
in narrower latitudinal bands compared with pyroclasts in a modern
atmosphere. Atmospheric winds are generally slower under higher pressure
regimes; however, the final distance traveled by the pyroclasts depends
greatly on the location of the volcano and can either increase or
decrease with pressure. The directionality of the pyroclast transport,
however, remains dominantly east or west along lines of latitude.
Augmentation of the atmospheric pressure improves the fit between
possible ash sources Arsia and Pavonis Mons and the Medusae Fossae
Formation, a hypothesized ash deposit.
  doi = {10.1016/j.icarus.2012.11.037},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{McDunn}, T. and {Bougher}, S. and {Murphy}, J. and {Kleinb{\"o}Hl}, A. and 
	{Forget}, F. and {Smith}, M.},
  title = {{Characterization of middle-atmosphere polar warming at Mars}},
  journal = {Journal of Geophysical Research (Planets)},
  keywords = {Mars, atmosphere, polar warming, middle atmosphere},
  year = 2013,
  volume = 118,
  pages = {161-178},
  abstract = {{We characterize middle-atmosphere polar warming (PW) using nearly three
Martian years of temperature observations by the Mars Climate Sounder.
We report the observed structure of PW and share hypotheses as to
possible explanations, which have yet to be tested with global dynamical
models. In the data, PW manifested between p = 15 Pa and p =
4.8{\times}10$^{-3}$ Pa. The latitude where PW maximized shifted
poleward with decreasing pressure. The nightside magnitude was larger
than the dayside magnitude. The maximum nightside magnitudes ranged from
22 to 67 K. As expected, the annual maximum magnitude in the north
occurred during late-local fall to middle-local winter. In the south it
occurred during late-local winter. Also as expected, the maximum
magnitude near MY 28's southern winter solstice was smaller than that at
that same year's northern winter solstice, when a global dust storm was
occurring. Unexpectedly, the maximum magnitude at southern winter
solstice was comparable to that at northern winter solstice for both MY
29 and MY 30, years that did not experience global dust storms but
certainly experienced greater dust loading during L$_{s}$ =
270{\deg} than L$_{s}$ = 90{\deg}. Another unexpected result was a
hemispheric asymmetry in PW magnitude during most of the observed
equinoxes. This paper also provides tables of (1) averaged temperatures
as a function of latitude, pressure, and season, and (2) the maximum
polar warming features as a function of pressure and season. These
tables can be used to validate GCM calculations of middle-atmosphere
temperatures and constrain calculations of unobserved winds.
  doi = {10.1002/jgre.20016},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Oshchepkov}, S. and {Bril}, A. and {Yokota}, T. and {Wennberg}, P.~O. and 
	{Deutscher}, N.~M. and {Wunch}, D. and {Toon}, G.~C. and {Yoshida}, Y. and 
	{O'Dell}, C.~W. and {Crisp}, D. and {Miller}, C.~E. and {Frankenberg}, C. and 
	{Butz}, A. and {Aben}, I. and {Guerlet}, S. and {Hasekamp}, O. and 
	{Boesch}, H. and {Cogan}, A. and {Parker}, R. and {Griffith}, D. and 
	{Macatangay}, R. and {Notholt}, J. and {Sussmann}, R. and {Rettinger}, M. and 
	{Sherlock}, V. and {Robinson}, J. and {Kyr{\"o}}, E. and {Heikkinen}, P. and 
	{Feist}, D.~G. and {Morino}, I. and {Kadygrov}, N. and {Belikov}, D. and 
	{Maksyutov}, S. and {Matsunaga}, T. and {Uchino}, O. and {Watanabe}, H.
  title = {{Effects of atmospheric light scattering on spectroscopic observations of greenhouse gases from space. Part 2: Algorithm intercomparison in the GOSAT data processing for CO$_{2}$ retrievals over TCCON sites}},
  journal = {Journal of Geophysical Research (Atmospheres)},
  keywords = {GOSAT algorithms},
  year = 2013,
  volume = 118,
  pages = {1493-1512},
  abstract = {{This report is the second in a series of companion papers describing the
effects of atmospheric light scattering in observations of atmospheric
carbon dioxide (CO$_{2}$) by the Greenhouse gases Observing
SATellite (GOSAT), in orbit since 23 January 2009. Here we summarize the
retrievals from six previously published algorithms; retrieving
column-averaged dry air mole fractions of CO$_{2}$
First, we compare data products from each algorithm with ground-based
remote sensing observations by Total Carbon Column Observing Network
(TCCON). Our GOSAT-TCCON coincidence criteria select satellite
observations within a 5{\deg} radius of 11 TCCON sites. We have compared
the GOSAT-TCCON X$_{CO2}$ regression slope, standard deviation,
correlation and determination coefficients, and global and
station-to-station biases. The best agreements with TCCON measurements
were detected for NIES 02.xx and RemoTeC. Next, the impact of
atmospheric light scattering on X$_{CO2}$ retrievals was estimated
for each data product using scan by scan retrievals of light path
modification with the photon path length probability density function
(PPDF) method. After a cloud pre-filtering test, approximately 25\% of
GOSAT soundings processed by NIES 02.xx, ACOS B2.9, and UoL-FP: 3G and
35\% processed by RemoTeC were found to be contaminated by atmospheric
light scattering. This study suggests that NIES 02.xx and ACOS B2.9
algorithms tend to overestimate aerosol amounts over bright surfaces,
resulting in an underestimation of X$_{CO2}$ for GOSAT
observations. Cross-comparison between algorithms shows that ACOS B2.9
agrees best with NIES 02.xx and UoL-FP: 3G while RemoTeC X$_{CO2}$
retrievals are in a best agreement with NIES PPDF-D.
  doi = {10.1002/jgrd.50146},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Reuter}, M. and {B{\"o}sch}, H. and {Bovensmann}, H. and {Bril}, A. and 
	{Buchwitz}, M. and {Butz}, A. and {Burrows}, J.~P. and {O'Dell}, C.~W. and 
	{Guerlet}, S. and {Hasekamp}, O. and {Heymann}, J. and {Kikuchi}, N. and 
	{Oshchepkov}, S. and {Parker}, R. and {Pfeifer}, S. and {Schneising}, O. and 
	{Yokota}, T. and {Yoshida}, Y.},
  title = {{A joint effort to deliver satellite retrieved atmospheric CO$_{2}$ concentrations for surface flux inversions: the ensemble median algorithm EMMA}},
  journal = {Atmospheric Chemistry \& Physics},
  year = 2013,
  volume = 13,
  pages = {1771-1780},
  abstract = {{We analyze an ensemble of seven XCO$_{2}$ retrieval algorithms for
SCIAMACHY (scanning imaging absorption spectrometer of atmospheric
chartography) and GOSAT (greenhouse gases observing satellite). The
ensemble spread can be interpreted as regional uncertainty and can help
to identify locations for new TCCON (total carbon column observing
network) validation sites. Additionally, we introduce the ensemble
median algorithm EMMA combining individual soundings of the seven
algorithms into one new data set. The ensemble takes advantage of the
algorithms' independent developments. We find ensemble spreads being
often $\lt$ 1 ppm but rising up to 2 ppm especially in the tropics and
all individual algorithms with TCCON and CarbonTracker model results
(potential outliers, north/south gradient, seasonal (peak-to-peak)
amplitude, standard deviation of the difference). Our findings show that
EMMA is a promising candidate for inverse modeling studies. Compared to
CarbonTracker, the satellite retrievals find consistently larger
north/south gradients (by 0.3-0.9 ppm) and seasonal amplitudes (by
1.5-2.0 ppm).
  doi = {10.5194/acp-13-1771-2013},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Haberle}, R.~M. and {Forget}, F. and {Head}, J. and {Kahre}, M.~A. and 
	{Kreslavsky}, M. and {Owen}, S.~J.},
  title = {{Summary of the Mars recent climate change workshop NASA/Ames Research Center, May 15-17, 2012}},
  journal = {\icarus},
  year = 2013,
  volume = 222,
  pages = {415-418},
  abstract = {{This note summarizes the results from the Mars recent climate change
workshop at NASA/Ames Research Center, May 15-17, 2012.
  doi = {10.1016/j.icarus.2012.10.009},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Forget}, F. and {Wordsworth}, R. and {Millour}, E. and {Madeleine}, J.-B. and 
	{Kerber}, L. and {Leconte}, J. and {Marcq}, E. and {Haberle}, R.~M.
  title = {{3D modelling of the early martian climate under a denser CO$_{2}$ atmosphere: Temperatures and CO$_{2}$ ice clouds}},
  journal = {\icarus},
  archiveprefix = {arXiv},
  eprint = {1210.4216},
  primaryclass = {astro-ph.EP},
  year = 2013,
  volume = 222,
  pages = {81-99},
  abstract = {{On the basis of geological evidence, it is often stated that the early
martian climate was warm enough for liquid water to flow on the surface
thanks to the greenhouse effect of a thick atmosphere. We present 3D
global climate simulations of the early martian climate performed
assuming a faint young Sun and a CO$_{2}$ atmosphere with surface
pressure between 0.1 and 7 bars. The model includes a detailed radiative
transfer model using revised CO$_{2}$ gas collision induced
absorption properties, and a parameterisation of the CO$_{2}$ ice
cloud microphysical and radiative properties. A wide range of possible
climates is explored using various values of obliquities, orbital
parameters, cloud microphysic parameters, atmospheric dust loading, and
surface properties. Unlike on present day Mars, for pressures higher
than a fraction of a bar, surface temperatures vary with altitude
because of the adiabatic cooling and warming of the atmosphere when it
moves vertically. In most simulations, CO$_{2}$ ice clouds cover a
major part of the planet. Previous studies had suggested that they could
have warmed the planet thanks to their scattering greenhouse effect.
However, even assuming parameters that maximize this effect, it does not
exceed +15 K. Combined with the revised CO$_{2}$ spectroscopy and
the impact of surface CO$_{2}$ ice on the planetary albedo, we
find that a CO$_{2}$ atmosphere could not have raised the annual
mean temperature above 0 {\deg}C anywhere on the planet. The collapse of
the atmosphere into permanent CO$_{2}$ ice caps is predicted for
pressures higher than 3 bar, or conversely at pressure lower than 1 bar
if the obliquity is low enough. Summertime diurnal mean surface
temperatures above 0 {\deg}C (a condition which could have allowed rivers
and lakes to form) are predicted for obliquity larger than 40{\deg} at
high latitudes but not in locations where most valley networks or
layered sedimentary units are observed. In the absence of other warming
mechanisms, our climate model results are thus consistent with a cold
early Mars scenario in which nonclimatic mechanisms must occur to
explain the evidence for liquid water. In a companion paper by
Wordsworth et al. we simulate the hydrological cycle on such a planet
and discuss how this could have happened in more detail.
  doi = {10.1016/j.icarus.2012.10.019},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Wordsworth}, R. and {Forget}, F. and {Millour}, E. and {Head}, J.~W. and 
	{Madeleine}, J.-B. and {Charnay}, B.},
  title = {{Global modelling of the early martian climate under a denser CO$_{2}$ atmosphere: Water cycle and ice evolution}},
  journal = {\icarus},
  archiveprefix = {arXiv},
  eprint = {1207.3993},
  primaryclass = {astro-ph.EP},
  year = 2013,
  volume = 222,
  pages = {1-19},
  abstract = {{We discuss 3D global simulations of the early martian climate that we
have performed assuming a faint young Sun and denser CO$_{2}$
atmosphere. We include a self-consistent representation of the water
cycle, with atmosphere-surface interactions, atmospheric transport, and
the radiative effects of CO$_{2}$ and H$_{2}$O gas and
clouds taken into account. We find that for atmospheric pressures
greater than a fraction of a bar, the adiabatic cooling effect causes
temperatures in the southern highland valley network regions to fall
significantly below the global average. Long-term climate evolution
simulations indicate that in these circumstances, water ice is
transported to the highlands from low-lying regions for a wide range of
orbital obliquities, regardless of the extent of the Tharsis bulge. In
addition, an extended water ice cap forms on the southern pole,
approximately corresponding to the location of the Noachian/Hesperian
era Dorsa Argentea Formation. Even for a multiple-bar CO$_{2}$
atmosphere, conditions are too cold to allow long-term surface liquid
water. Limited melting occurs on warm summer days in some locations, but
only for surface albedo and thermal inertia conditions that may be
unrealistic for water ice. Nonetheless, meteorite impacts and volcanism
could potentially cause intense episodic melting under such conditions.
Because ice migration to higher altitudes is a robust mechanism for
recharging highland water sources after such events, we suggest that
this globally sub-zero, 'icy highlands' scenario for the late Noachian
climate may be sufficient to explain most of the fluvial geology without
the need to invoke additional long-term warming mechanisms or an early
warm, wet Mars.
  doi = {10.1016/j.icarus.2012.09.036},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
  author = {{Forget}, F. and {Lebonnois}, S.},
  title = {{Global Climate Models of the Terrestrial Planets}},
  journal = {Comparative Climatology of Terrestrial Planets},
  year = 2013,
  editor = {{Mackwell}, S.~J. and {Simon-Miller}, A.~A. and {Harder}, J.~W. and 
	{Bullock}, M.~A.},
  pages = {213-229},
  abstract = {{On the basis of the global climate models (GCMs) originally developed
for Earth, several teams around the world have been able to develop GCMs
for the atmospheres of the other terrestrial bodies in our solar system:
 Venus, Mars, Titan, Triton, and Pluto. In spite of the apparent
complexity of climate systems and meteorology, GCMs are based on a
limited number of equations. In practice, relatively complete climate
simulators can be developed by combining a few components such as a
dynamical core, a radiative transfer solver, a parameterization of
turbulence and convection, a thermal ground model, and a volatile phase
change code, possibly completed by a few specific schemes. It can be
shown that many of these GCM components are ``universal'' so that we can
envisage building realistic climate models for any kind of terrestrial
planets and atmospheres that we can imagine. Such a tool is useful for
conducting scientific investigations on the possible climates of
terrestrial extrasolar planets, or to study past environments in the
solar system. The ambition behind the development of GCMs is high:  The
ultimate goal is to build numerical simulators based only on universal
physical or chemical equations, yet able to reproduce or predict all the
available observations on a given planet, without any ad hoc forcing. In
other words, we aim to virtually create in our computers planets that
``behave'' exactly like the actual planets themselves. In reality, of
course, nature is always more complex than expected, but we learn a lot
in the process. In this chapter we detail some lessons learned in the
solar system:  In many cases, GCMs work. They have been able to simulate
many aspects of planetary climates without difficulty. In some cases,
however, problems have been encountered, sometimes simply because a key
process has been forgotten in the model or is not yet correctly
parameterized, but also because sometimes the climate regime seems to be
result of a subtle balance between processes that remain highly model
sensitive, or are the subject of positive feedback and unstability. In
any case, building virtual planets with GCMs, in light of the
observations obtained by spacecraft or from Earth, is a true scientific
endeavor that can teach us a lot about the complex nature of climate
  doi = {10.2458/azu_uapress_9780816530595-ch010},
  adsurl = {},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}