lmd_EMC32012.bib
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@article{2012QJRMS.138.2182S,
author = {{Sane}, Y. and {Bonazzola}, M. and {Rio}, C. and {Chambon}, P. and
{Fiolleau}, T. and {Musat}, I. and {Hourdin}, F. and {Roca}, R. and
{Grandpeix}, J.-Y. and {Diedhiou}, A.},
title = {{An analysis of the diurnal cycle of precipitation over Dakar using local rain-gauge data and a general circulation model}},
journal = {Quarterly Journal of the Royal Meteorological Society},
year = 2012,
month = oct,
volume = 138,
pages = {2182-2195},
doi = {10.1002/qj.1932},
adsurl = {http://adsabs.harvard.edu/abs/2012QJRMS.138.2182S},
adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2012GeoRL..3921801N,
author = {{Nam}, C. and {Bony}, S. and {Dufresne}, J.-L. and {Chepfer}, H.
},
title = {{The {\lsquo}too few, too bright{\rsquo} tropical low-cloud problem in CMIP5 models}},
journal = {\grl},
keywords = {Atmospheric Composition and Structure: Cloud/radiation interaction, Atmospheric Composition and Structure: Radiation: transmission and scattering, Global Change: Atmosphere (0315, 0325), Global Change: Earth system modeling (1225, 4316), Global Change: Global climate models (3337, 4928)},
year = 2012,
month = nov,
volume = 39,
eid = {L21801},
pages = {21801},
abstract = {{Previous generations of climate models have been shown to under-estimate
the occurrence of tropical low-level clouds and to over-estimate their
radiative effects. This study analyzes outputs from multiple climate
models participating in the Fifth phase of the Coupled Model
Intercomparison Project (CMIP5) using the Cloud Feedback Model
Intercomparison Project Observations Simulator Package (COSP), and
compares them with different satellite data sets. Those include CALIPSO
lidar observations, PARASOL mono-directional reflectances and CERES
radiative fluxes at the top of the atmosphere. We show that current
state-of-the-art climate models predict overly bright low-clouds, even
for a correct low-cloud cover. The impact of these biases on the Earth'
radiation budget, however, is reduced by compensating errors. Those
include the tendency of models to under-estimate the low-cloud cover and
to over-estimate the occurrence of mid- and high-clouds above
low-clouds. Finally, we show that models poorly represent the dependence
of the vertical structure of low-clouds on large-scale environmental
conditions. The implications of this {\lsquo}too few, too bright
low-cloud problem{\rsquo} for climate sensitivity and model development
are discussed.
}},
doi = {10.1029/2012GL053421},
adsurl = {http://adsabs.harvard.edu/abs/2012GeoRL..3921801N},
adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2012ACP....1210817L,
author = {{Lacour}, J.-L. and {Risi}, C. and {Clarisse}, L. and {Bony}, S. and
{Hurtmans}, D. and {Clerbaux}, C. and {Coheur}, P.-F.},
title = {{Mid-tropospheric {$\delta$}D observations from IASI/MetOp at high spatial and temporal resolution}},
journal = {Atmospheric Chemistry \& Physics},
year = 2012,
month = nov,
volume = 12,
pages = {10817-10832},
abstract = {{In this paper we retrieve atmospheric HDO, H$_{2}$O concentrations
and their ratio {$\delta$}D from IASI radiances spectra. Our method relies
on an existing radiative transfer model (Atmosphit) and an optimal
estimation inversion scheme, but goes further than our previous work by
explicitly considering correlations between the two species. A global
HDO and H$_{2}$O a priori profile together with a covariance
matrix were built from daily LMDz-iso model simulations of HDO and
H$_{2}$O profiles over the whole globe and a whole year. The
retrieval parameters are described and characterized in terms of errors.
We show that IASI is mostly sensitive to {$\delta$}D in the middle
troposphere and allows retrieving {$\delta$}D for an integrated 3-6 km
column with an error of 38{\permil} on an individual measurement basis.
We examine the performance of the retrieval to capture the temporal
(seasonal and short-term) and spatial variations of {$\delta$}D for one
year of measurement at two dedicated sites (Darwin and Iza{\~n}a) and
a latitudinal band from -60{\deg} to 60{\deg} for a 15 day period in
January. We report a generally good agreement between IASI and the model
and indicate the capabilities of IASI to reproduce the large scale
variations of {$\delta$}D (seasonal cycle and latitudinal gradient) with
good accuracy. In particular, we show that there is no systematic
significant bias in the retrieved {$\delta$}D values in comparison with the
model, and that the retrieved variability is similar to the one in the
model even though there are certain local differences. Moreover, the
noticeable differences between IASI and the model are briefly examined
and suggest modeling issues instead of retrieval effects. Finally, the
results further reveal the unprecedented capabilities of IASI to capture
short-term variations in {$\delta$}D, highlighting the added value of the
sounder for monitoring hydrological processes.
}},
doi = {10.5194/acp-12-10817-2012},
adsurl = {http://adsabs.harvard.edu/abs/2012ACP....1210817L},
adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2012JGRD..117.5304R,
author = {{Risi}, C. and {Noone}, D. and {Worden}, J. and {Frankenberg}, C. and
{Stiller}, G. and {Kiefer}, M. and {Funke}, B. and {Walker}, K. and
{Bernath}, P. and {Schneider}, M. and {Bony}, S. and {Lee}, J. and
{Brown}, D. and {Sturm}, C.},
title = {{Process-evaluation of tropospheric humidity simulated by general circulation models using water vapor isotopic observations: 2. Using isotopic diagnostics to understand the mid and upper tropospheric moist bias in the tropics and subtropics}},
journal = {Journal of Geophysical Research (Atmospheres)},
keywords = {general circulation models, process-based evaluation, relative humidity, water isotopes, Atmospheric Composition and Structure: Cloud physics and chemistry, Atmospheric Composition and Structure: Troposphere: composition and chemistry, Atmospheric Processes: Global climate models (1626, 4928), Atmospheric Processes: Remote sensing (4337)},
year = 2012,
month = mar,
volume = 117,
eid = {D05304},
pages = {5304},
abstract = {{Evaluating the representation of processes controlling tropical and
subtropical tropospheric relative humidity (RH) in atmospheric general
circulation models (GCMs) is crucial to assess the credibility of
predicted climate changes. GCMs have long exhibited a moist bias in the
tropical and subtropical mid and upper troposphere, which could be due
to the mis-representation of cloud processes or of the large-scale
circulation, or to excessive diffusion during water vapor transport. The
goal of this study is to use observations of the water vapor isotopic
ratio to understand the cause of this bias. We compare the
three-dimensional distribution of the water vapor isotopic ratio
measured from space and ground to that simulated by several versions of
the isotopic GCM LMDZ. We show that the combined evaluation of RH and of
the water vapor isotopic composition makes it possible to discriminate
the most likely cause of RH biases. Models characterized either by an
excessive vertical diffusion, an excessive convective detrainment or an
underestimated in situ cloud condensation will all produce a moist bias
in the free troposphere. However, only an excessive vertical diffusion
can lead to a reversed seasonality of the free tropospheric isotopic
composition in the subtropics compared to observations. Comparing seven
isotopic GCMs suggests that the moist bias found in many GCMs in the mid
and upper troposphere most frequently results from an excessive
diffusion during vertical water vapor transport. This study demonstrates
the added value of water vapor isotopic measurements for interpreting
shortcomings in the simulation of RH by climate models.
}},
doi = {10.1029/2011JD016623},
adsurl = {http://adsabs.harvard.edu/abs/2012JGRD..117.5304R},
adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2012JGRD..117.5303R,
author = {{Risi}, C. and {Noone}, D. and {Worden}, J. and {Frankenberg}, C. and
{Stiller}, G. and {Kiefer}, M. and {Funke}, B. and {Walker}, K. and
{Bernath}, P. and {Schneider}, M. and {Wunch}, D. and {Sherlock}, V. and
{Deutscher}, N. and {Griffith}, D. and {Wennberg}, P.~O. and
{Strong}, K. and {Smale}, D. and {Mahieu}, E. and {Barthlott}, S. and
{Hase}, F. and {Garc{\'{\i}}A}, O. and {Notholt}, J. and {Warneke}, T. and
{Toon}, G. and {Sayres}, D. and {Bony}, S. and {Lee}, J. and
{Brown}, D. and {Uemura}, R. and {Sturm}, C.},
title = {{Process-evaluation of tropospheric humidity simulated by general circulation models using water vapor isotopologues: 1. Comparison between models and observations}},
journal = {Journal of Geophysical Research (Atmospheres)},
keywords = {general circulation models, process-based evaluation, relative humidity, water isotopes, Atmospheric Composition and Structure: Cloud physics and chemistry, Atmospheric Composition and Structure: Troposphere: composition and chemistry, Atmospheric Processes: Global climate models (1626, 4928), Atmospheric Processes: Regional modeling (4316), Paleoceanography: Global climate models (1626, 3337)},
year = 2012,
month = mar,
volume = 117,
eid = {D05303},
pages = {5303},
abstract = {{The goal of this study is to determine how H$_{2}$O and HDO
measurements in water vapor can be used to detect and diagnose biases in
the representation of processes controlling tropospheric humidity in
atmospheric general circulation models (GCMs). We analyze a large number
of isotopic data sets (four satellite, sixteen ground-based
remote-sensing, five surface in situ and three aircraft data sets) that
are sensitive to different altitudes throughout the free troposphere.
Despite significant differences between data sets, we identify some
observed HDO/H$_{2}$O characteristics that are robust across data
sets and that can be used to evaluate models. We evaluate the isotopic
GCM LMDZ, accounting for the effects of spatiotemporal sampling and
instrument sensitivity. We find that LMDZ reproduces the spatial
patterns in the lower and mid troposphere remarkably well. However, it
underestimates the amplitude of seasonal variations in isotopic
composition at all levels in the subtropics and in midlatitudes, and
this bias is consistent across all data sets. LMDZ also underestimates
the observed meridional isotopic gradient and the contrast between dry
and convective tropical regions compared to satellite data sets.
Comparison with six other isotope-enabled GCMs from the SWING2 project
shows that biases exhibited by LMDZ are common to all models. The SWING2
GCMs show a very large spread in isotopic behavior that is not obviously
related to that of humidity, suggesting water vapor isotopic
measurements could be used to expose model shortcomings. In a companion
paper, the isotopic differences between models are interpreted in terms
of biases in the representation of processes controlling humidity.
}},
doi = {10.1029/2011JD016621},
adsurl = {http://adsabs.harvard.edu/abs/2012JGRD..117.5303R},
adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2012JAtS...69.3788A,
author = {{Arakelian}, A. and {Codron}, F.},
title = {{Southern Hemisphere Jet Variability in the IPSL GCM at Varying Resolutions}},
journal = {Journal of Atmospheric Sciences},
year = 2012,
month = dec,
volume = 69,
pages = {3788-3799},
doi = {10.1175/JAS-D-12-0119.1},
adsurl = {http://adsabs.harvard.edu/abs/2012JAtS...69.3788A},
adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2012GeoRL..3923202M,
author = {{Madeleine}, J.-B. and {Forget}, F. and {Millour}, E. and {Navarro}, T. and
{Spiga}, A.},
title = {{The influence of radiatively active water ice clouds on the Martian climate}},
journal = {\grl},
keywords = {Atmospheric Composition and Structure: Cloud/radiation interaction, Atmospheric Composition and Structure: Planetary atmospheres (5210, 5405, 5704), Atmospheric Processes: Clouds and cloud feedbacks, Planetary Sciences: Solid Surface Planets: Atmospheres (0343, 1060), Planetary Sciences: Solar System Objects: Mars},
year = 2012,
month = dec,
volume = 39,
eid = {L23202},
pages = {23202},
abstract = {{Radiatively active water ice clouds (RAC) play a key role in shaping the
thermal structure of the Martian atmosphere. In this paper, RAC are
implemented in the LMD Mars Global Climate Model (GCM) and the simulated
temperatures are compared to Thermal Emission Spectrometer observations
over a full year. RAC change the temperature gradients and global
dynamics of the atmosphere and this change in dynamics in turn implies
large-scale adiabatic temperature changes. Therefore, clouds have both a
direct and indirect effect on atmospheric temperatures. RAC successfully
reduce major GCM temperature biases, especially in the regions of
formation of the aphelion cloud belt where a cold bias of more than 10 K
is corrected. Departures from the observations are however seen in the
polar regions, and highlight the need for better modeling of cloud
formation and evolution.
}},
doi = {10.1029/2012GL053564},
adsurl = {http://adsabs.harvard.edu/abs/2012GeoRL..3923202M},
adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2012ClDy...39.2091K,
author = {{Konsta}, D. and {Chepfer}, H. and {Dufresne}, J.-L.},
title = {{A process oriented characterization of tropical oceanic clouds for climate model evaluation, based on a statistical analysis of daytime A-train observations}},
journal = {Climate Dynamics},
year = 2012,
month = nov,
volume = 39,
pages = {2091-2108},
abstract = {{This paper aims at characterizing how different key cloud properties
(cloud fraction, cloud vertical distribution, cloud reflectance, a
surrogate of the cloud optical depth) vary as a function of the others
over the tropical oceans. The correlations between the different cloud
properties are built from 2 years of collocated A-train observations
(CALIPSO-GOCCP and MODIS) at a scale close to cloud processes; it
results in a characterization of the physical processes in tropical
clouds, that can be used to better understand cloud behaviors, and
constitute a powerful tool to develop and evaluate cloud
parameterizations in climate models. First, we examine a case study of
shallow cumulus cloud observed simultaneously by the two sensors
(CALIPSO, MODIS), and develop a methodology that allows to build global
scale statistics by keeping the separation between clear and cloudy
areas at the pixel level (250, 330 m). Then we build statistical
instantaneous relationships between the cloud cover, the cloud vertical
distribution and the cloud reflectance. The vertical cloud distribution
indicates that the optically thin clouds (optical thickness {\lt}1.5)
dominate the boundary layer over the trade wind regions. Optically thick
clouds (optical thickness {\gt}3.4) are composed of high and mid-level
clouds associated with deep convection along the ITCZ and SPCZ and over
the warm pool, and by stratocumulus low level clouds located along the
East coast of tropical oceans. The cloud properties are analyzed as a
function of the large scale circulation regime. Optically thick high
clouds are dominant in convective regions (CF {\gt} 80 \%), while low
level clouds with low optical thickness ({\lt}3.5) are present in regimes
of subsidence but in convective regimes as well, associated principally
to low cloud fractions (CF {\lt} 50 \%). A focus on low-level clouds
allows us to quantify how the cloud optical depth increases with cloud
top altitude and with cloud fraction.
}},
doi = {10.1007/s00382-012-1533-7},
adsurl = {http://adsabs.harvard.edu/abs/2012ClDy...39.2091K},
adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2012ACP....1210485F,
author = {{Field}, R.~D. and {Risi}, C. and {Schmidt}, G.~A. and {Worden}, J. and
{Voulgarakis}, A. and {LeGrande}, A.~N. and {Sobel}, A.~H. and
{Healy}, R.~J.},
title = {{A Tropospheric Emission Spectrometer HDO/H$_{2}$O retrieval simulator for climate models}},
journal = {Atmospheric Chemistry \& Physics},
year = 2012,
month = nov,
volume = 12,
pages = {10485-10504},
abstract = {{Retrievals of the isotopic composition of water vapor from the Aura
Tropospheric Emission Spectrometer (TES) have unique value in
constraining moist processes in climate models. Accurate comparison
between simulated and retrieved values requires that model profiles that
would be poorly retrieved are excluded, and that an instrument operator
be applied to the remaining profiles. Typically, this is done by
sampling model output at satellite measurement points and using the
quality flags and averaging kernels from individual retrievals at
specific places and times. This approach is not reliable when the model
meteorological conditions influencing retrieval sensitivity are
different from those observed by the instrument at short time scales,
which will be the case for free-running climate simulations. In this
study, we describe an alternative, ''categorical'' approach to applying
the instrument operator, implemented within the NASA GISS ModelE general
circulation model. Retrieval quality and averaging kernel structure are
predicted empirically from model conditions, rather than obtained from
collocated satellite observations. This approach can be used for
arbitrary model configurations, and requires no agreement between
satellite-retrieved and model meteorology at short time scales. To test
this approach, nudged simulations were conducted using both the
retrieval-based and categorical operators. Cloud cover, surface
temperature and free-tropospheric moisture content were the most
important predictors of retrieval quality and averaging kernel
structure. There was good agreement between the {$\delta$}D fields after
applying the retrieval-based and more detailed categorical operators,
with increases of up to 30{\permil} over the ocean and decreases of up to
40{\permil} over land relative to the raw model fields. The categorical
operator performed better over the ocean than over land, and requires
further refinement for use outside of the tropics. After applying the
TES operator, ModelE had {$\delta$}D biases of -8{\permil} over ocean and
-34{\permil} over land compared to TES {$\delta$}D, which were less than the
biases using raw model {$\delta$}D fields.
}},
doi = {10.5194/acp-12-10485-2012},
adsurl = {http://adsabs.harvard.edu/abs/2012ACP....1210485F},
adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2012JGRD..11719205S,
author = {{Sherwood}, S.~C. and {Risi}, C.},
title = {{The HDO/H$_{2}$O relationship in tropospheric water vapor in an idealized {\ldquo}last-saturation{\rdquo} model}},
journal = {Journal of Geophysical Research (Atmospheres)},
keywords = {atmospheric convection, climate, isotopes, water vapor, Atmospheric Composition and Structure: Cloud physics and chemistry, Atmospheric Composition and Structure: Troposphere: composition and chemistry, Global Change: Water cycles (1836), Atmospheric Processes: Convective processes, Atmospheric Processes: Idealized model},
year = 2012,
month = oct,
volume = 117,
number = d16,
eid = {D19205},
pages = {19205},
abstract = {{Previous model studies have shown that the isotopic composition of
tropospheric water vapor is sensitive to atmospheric water transport
processes, but compositional information is difficult to interpret due
to the complexity of the models. Here an attempt is made to clarify the
sensitivity by computing the relationship between tropospheric HDO (via
{$\delta$}D) and H$_{2}$O (via specific humidity q) in an idealized
model atmosphere based on a ''last-saturation'' framework that includes
convection coupled to a steady large-scale circulation with prescribed
horizontal mixing. Multiple physical representations of convection and
mixing allow key structural as well as parametric uncertainties to be
explored. This model has previously been shown to reproduce the
essential aspects of the humidity distribution. Variations of{$\delta$}D or
qindividually are dominated by local dynamics, but their relationship is
preserved advectively, thus revealing conditions in regions of
convection. The model qualitatively agrees with satellite observations,
and reproduces some parametric sensitivities seen in previous GCM
experiments. Sensitivity to model assumptions is greatest in the upper
troposphere, apparently because in-situ evaporation and condensation
processes in convective regions are more dominant in the budget there.
In general, vapor recycling analogous to that in continental interiors
emerges as the crucial element in explaining why{$\delta$}D exceeds that
predicted by a simple Rayleigh process; such recycling involves
coexistent condensation sinks and convective moisture sources, induced
respectively by (for example) waves and small-scale convective mixing.
The relative humidity distribution is much less sensitive to such
recycling.
}},
doi = {10.1029/2012JD018068},
adsurl = {http://adsabs.harvard.edu/abs/2012JGRD..11719205S},
adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2012JGRD..11719201M,
author = {{Mrowiec}, A.~A. and {Rio}, C. and {Fridlind}, A.~M. and {Ackerman}, A.~S. and
{Del Genio}, A.~D. and {Pauluis}, O.~M. and {Varble}, A.~C. and
{Fan}, J.},
title = {{Analysis of cloud-resolving simulations of a tropical mesoscale convective system observed during TWP-ICE: Vertical fluxes and draft properties in convective and stratiform regions}},
journal = {Journal of Geophysical Research (Atmospheres)},
keywords = {TWP-ICE, cloud-resolving modeling, convection parameterization, mesoscale convective system, tropical convection, updrafts and downdrafts, Atmospheric Processes: Convective processes, Atmospheric Processes: Regional modeling (4316), Atmospheric Processes: Tropical convection},
year = 2012,
month = oct,
volume = 117,
number = d16,
eid = {D19201},
pages = {19201},
abstract = {{We analyze three cloud-resolving model simulations of a strong
convective event observed during the TWP-ICE campaign, differing in
dynamical core, microphysical scheme or both. Based on simulated and
observed radar reflectivity, simulations roughly reproduce observed
convective and stratiform precipitating areas. To identify the
characteristics of convective and stratiform drafts that are difficult
to observe but relevant to climate model parameterization, independent
vertical wind speed thresholds are calculated to capture 90\% of total
convective and stratiform updraft and downdraft mass fluxes. Convective
updrafts are fairly consistent across simulations (likely owing to fixed
large-scale forcings and surface conditions), except that hydrometeor
loadings differ substantially. Convective downdraft and stratiform
updraft and downdraft mass fluxes vary notably below the melting level,
but share similar vertically uniform draft velocities despite differing
hydrometeor loadings. All identified convective and stratiform
downdrafts contain precipitation below {\tilde}10 km and nearly all
updrafts are cloudy above the melting level. Cold pool properties
diverge substantially in a manner that is consistent with convective
downdraft mass flux differences below the melting level. Despite
differences in hydrometeor loadings and cold pool properties, convective
updraft and downdraft mass fluxes are linearly correlated with
convective area, the ratio of ice in downdrafts to that in updrafts is
{\tilde}0.5 independent of species, and the ratio of downdraft to updraft
mass flux is {\tilde}0.5-0.6, which may represent a minimum evaporation
efficiency under moist conditions. Hydrometeor loading in stratiform
regions is found to be a fraction of hydrometeor loading in convective
regions that ranges from {\tilde}10\% (graupel) to {\tilde}90\% (cloud ice).
These findings may lead to improved convection parameterizations.
}},
doi = {10.1029/2012JD017759},
adsurl = {http://adsabs.harvard.edu/abs/2012JGRD..11719201M},
adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2012JCli...25.6885T,
author = {{Tobin}, I. and {Bony}, S. and {Roca}, R.},
title = {{Observational Evidence for Relationships between the Degree of Aggregation of Deep Convection, Water Vapor, Surface Fluxes, and Radiation}},
journal = {Journal of Climate},
year = 2012,
month = oct,
volume = 25,
pages = {6885-6904},
doi = {10.1175/JCLI-D-11-00258.1},
adsurl = {http://adsabs.harvard.edu/abs/2012JCli...25.6885T},
adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2012GeoRL..3920807B,
author = {{Brient}, F. and {Bony}, S.},
title = {{How may low-cloud radiative properties simulated in the current climate influence low-cloud feedbacks under global warming?}},
journal = {\grl},
keywords = {Atmospheric Composition and Structure: Cloud/radiation interaction, Global Change: Atmosphere (0315, 0325), Global Change: Global climate models (3337, 4928), Atmospheric Processes: Clouds and cloud feedbacks},
year = 2012,
month = oct,
volume = 39,
eid = {L20807},
pages = {20807},
abstract = {{The influence of cloud modelling uncertainties on the projection of the
tropical low-cloud response to global warming is explored by perturbing
model parameters of the IPSL-CM5A climate model in a range of
configurations (realistic general circulation model, aqua-planet,
single-column model). While the positive sign and the mechanism of the
low-cloud response to climate warming predicted by the model are robust,
the amplitude of the response can vary considerably depending on the
model tuning parameters. Moreover, the strength of the low-cloud
response to climate change exhibits a strong correlation with the
strength of the low-cloud radiative effects simulated in the current
climate. We show that this correlation primarily results from a local
positive feedback (referred to as the {\ldquo}beta feedback{\rdquo})
between boundary-layer cloud radiative cooling, relative humidity and
low-cloud cover. Based on this correlation and observational
constraints, it is suggested that the strength of the tropical low-cloud
feedback predicted by the IPSL-CM5A model in climate projections might
be overestimated by about fifty percent.
}},
doi = {10.1029/2012GL053265},
adsurl = {http://adsabs.harvard.edu/abs/2012GeoRL..3920807B},
adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2012ClDy...39.1329G,
author = {{Guimberteau}, M. and {Laval}, K. and {Perrier}, A. and {Polcher}, J.
},
title = {{Global effect of irrigation and its impact on the onset of the Indian summer monsoon}},
journal = {Climate Dynamics},
keywords = {Irrigation, ORCHIDEE, Indian monsoon, Onset, Mississippi},
year = 2012,
month = sep,
volume = 39,
pages = {1329-1348},
abstract = {{In a context of increased demand for food and of climate change, the
water consumptions associated with the agricultural practice of
irrigation focuses attention. In order to analyze the global influence
of irrigation on the water cycle, the land surface model ORCHIDEE is
coupled to the GCM LMDZ to simulate the impact of irrigation on climate.
A 30-year simulation which takes into account irrigation is compared
with a simulation which does not. Differences are usually not
significant on average over all land surfaces but hydrological variables
are significantly affected by irrigation over some of the main irrigated
river basins. Significant impacts over the Mississippi river basin are
shown to be contrasted between eastern and western regions. An increase
in summer precipitation is simulated over the arid western region in
association with enhanced evapotranspiration whereas a decrease in
precipitation occurs over the wet eastern part of the basin. Over the
Indian peninsula where irrigation is high during winter and spring, a
delay of 6 days is found for the mean monsoon onset date when irrigation
is activated, leading to a significant decrease in precipitation during
May to July. Moreover, the higher decrease occurs in June when the water
requirements by crops are maximum, exacerbating water scarcity in this
region. A significant cooling of the land surfaces occurs during the
period of high irrigation leading to a decrease of the land-sea heat
contrast in June, which delays the monsoon onset.
}},
doi = {10.1007/s00382-011-1252-5},
adsurl = {http://adsabs.harvard.edu/abs/2012ClDy...39.1329G},
adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2012JGRE..117.0J10C,
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.~A. and {Toigo}, A.~D. and {Humm}, D. and {Kass}, D.~M. and
{Kleinb{\"o}hl}, A. and {Heavens}, N.},
title = {{Extensive MRO CRISM observations of 1.27 {$\mu$}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 = {Planetary Sciences: Solid Surface Planets: Atmospheres (0343, 1060), Planetary Sciences: Solid Surface Planets: Aurorae and airglow, Planetary Sciences: Solid Surface Planets: Polar regions, Planetary Sciences: Solid Surface Planets: Remote sensing, Planetary Sciences: Solar System Objects: Mars},
year = 2012,
month = aug,
volume = 117,
eid = {E00J10},
pages = {0},
abstract = {{The Martian polar night distribution of 1.27 {$\mu$}m (0-0) band
emission from O$_{2}$ singlet delta
[O$_{2}$($^{1}${$\Delta$}$_{g}$)] is determined from an
extensive set of Mars Reconnaissance Orbiter (MRO) Compact
Reconnaissance Imaging Spectral Mapping (CRISM) limb scans observed over
a wide range of Mars seasons, high latitudes, local times, and
longitudes between 2009 and 2011. This polar nightglow reflects
meridional transport and winter polar descent of atomic oxygen produced
from CO$_{2}$ photodissociation. A distinct peak in 1.27 {$\mu$}m
nightglow appears prominently over 70-90NS latitudes at
40-60 km altitudes, as retrieved for over 100 vertical profiles of
O$_{2}$($^{1}${$\Delta$}$_{g}$) 1.27 {$\mu$}m volume
emission rates (VER). We also present the first detection of much
({\times}80 {\plusmn} 20) weaker 1.58 {$\mu$}m (0-1) band emission from
Mars O$_{2}$($^{1}${$\Delta$}$_{g}$). Co-located polar
night CRISM O$_{2}$($^{1}${$\Delta$}$_{g}$) and Mars
Climate Sounder (MCS) (McCleese et al., 2008) temperature profiles are
compared to the same profiles as simulated by the Laboratoire de
Météorologie Dynamique (LMD) general
circulation/photochemical model (e.g., Lefèvre et al., 2004).
Both standard and interactive aerosol LMD simulations (Madeleine et al.,
2011a) underproduce CRISM O$_{2}$($^{1}${$\Delta$}$_{g}$)
total emission rates by 40\%, due to inadequate transport of atomic
oxygen to the winter polar emission regions. Incorporation of
interactive cloud radiative forcing on the global circulation leads to
distinct but insufficient improvements in modeled polar
O$_{2}$($^{1}${$\Delta$}$_{g}$) and temperatures. The
observed and modeled anti-correlations between temperatures and 1.27
{$\mu$}m band VER reflect the temperature dependence of the rate
coefficient for O$_{2}$($^{1}${$\Delta$}$_{g}$)
formation, as provided in Roble (1995).
}},
doi = {10.1029/2011JE004018},
adsurl = {http://adsabs.harvard.edu/abs/2012JGRE..117.0J10C},
adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2012JGRD..11715112L,
author = {{Lee}, J.-E. and {Risi}, C. and {Fung}, I. and {Worden}, J. and
{Scheepmaker}, R.~A. and {Lintner}, B. and {Frankenberg}, C.
},
title = {{Asian monsoon hydrometeorology from TES and SCIAMACHY water vapor isotope measurements and LMDZ simulations: Implications for speleothem climate record interpretation}},
journal = {Journal of Geophysical Research (Atmospheres)},
keywords = {Asian monsoon, amount effect, climate modeling, insolation, speleothem, water isotopes, Global Change: Abrupt/rapid climate change (4901, 8408), Global Change: Climate variability (1635, 3305, 3309, 4215, 4513), Global Change: Cryospheric change (0776), Global Change: Impacts of global change (1225, 4321), Global Change: Remote sensing (1855, 4337)},
year = 2012,
month = aug,
volume = 117,
number = d16,
eid = {D15112},
pages = {15112},
abstract = {{Observations show that heavy oxygen isotope composition in precipitation
({$\delta$}$^{18}$O$_{p}$) increases from coastal southeastern
(SE) China to interior northwestern (NW) China during the wet season,
contradicting expectations from simple Rayleigh distillation theory.
Here we employ stable isotopes of precipitation and vapor from satellite
measurements and climate model simulations to characterize the moisture
processes that control Asian monsoon precipitation and relate these
processes to speleothem paleoclimate records. We find that
{$\delta$}$^{18}$O$_{p}$ is low over SE China as a result of
local and upstream condensation and that
{$\delta$}$^{18}$O$_{p}$ is high over NW China because of
evaporative enrichment of $^{18}$O as raindrops fall through dry
air. We show that {$\delta$}$^{18}$O$_{p}$ at cave sites over
southern China is weakly correlated with upstream precipitation in the
core of the Indian monsoon region rather than local precipitation, but
it is well-correlated with the {$\delta$}$^{18}$O$_{p}$ over
large areas of southern and central China, consistent with coherent
speleothem {$\delta$}$^{18}$O$_{p}$ variations over different
parts of China. Previous studies have documented high correlations
between speleothem {$\delta$}$^{18}$O$_{p}$ and millennial
timescale climate forcings, and we suggest that the high correlation
between insolation and speleothem {$\delta$}$^{18}$O$_{p}$ in
southern China reflects the variations of hydrologic processes over the
Indian monsoon region on millennial and orbital timescales. The
{$\delta$}$^{18}$O$_{p}$ in the drier part (north of
{\tilde}30{\deg}N) of China, on the other hand, has consistently negative
correlations with local precipitation and may capture local hydrologic
processes related to changes in the extent of the Hadley circulation.
}},
doi = {10.1029/2011JD017133},
adsurl = {http://adsabs.harvard.edu/abs/2012JGRD..11715112L},
adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2012ACP....12.6775B,
author = {{Browse}, J. and {Carslaw}, K.~S. and {Arnold}, S.~R. and {Pringle}, K. and
{Boucher}, O.},
title = {{The scavenging processes controlling the seasonal cycle in Arctic sulphate and black carbon aerosol}},
journal = {Atmospheric Chemistry \& Physics},
year = 2012,
month = aug,
volume = 12,
pages = {6775-6798},
abstract = {{The seasonal cycle in Arctic aerosol is typified by high concentrations
of large aged anthropogenic particles transported from lower latitudes
in the late Arctic winter and early spring followed by a sharp
transition to low concentrations of locally sourced smaller particles in
the summer. However, multi-model assessments show that many models fail
to simulate a realistic cycle. Here, we use a global aerosol
microphysics model (GLOMAP) and surface-level aerosol observations to
understand how wet scavenging processes control the seasonal variation
in Arctic black carbon (BC) and sulphate aerosol. We show that the
transition from high wintertime concentrations to low concentrations in
the summer is controlled by the transition from ice-phase cloud
scavenging to the much more efficient warm cloud scavenging in the late
spring troposphere. This seasonal cycle is amplified further by the
appearance of warm drizzling cloud in the late spring and summer
boundary layer. Implementing these processes in GLOMAP greatly improves
the agreement between the model and observations at the three Arctic
ground-stations Alert, Barrow and Zeppelin Mountain on Svalbard. The
SO$_{4}$ model-observation correlation coefficient (R) increases
from: -0.33 to 0.71 at Alert (82.5{\deg} N), from -0.16 to 0.70 at Point
Barrow (71.0{\deg} N) and from -0.42 to 0.40 at Zeppelin Mountain
(78{\deg} N). The BC model-observation correlation coefficient increases
from -0.68 to 0.72 at Alert and from -0.42 to 0.44 at Barrow.
Observations at three marginal Arctic sites (Janiskoski, Oulanka and
Karasjok) indicate a far weaker aerosol seasonal cycle, which we show is
consistent with the much smaller seasonal change in the frequency of ice
clouds compared to higher latitude sites. Our results suggest that the
seasonal cycle in Arctic aerosol is driven by temperature-dependent
scavenging processes that may be susceptible to modification in a future
climate.
}},
doi = {10.5194/acp-12-6775-2012},
adsurl = {http://adsabs.harvard.edu/abs/2012ACP....12.6775B},
adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2012JGRD..11714105J,
author = {{Jiang}, J.~H. and {Su}, H. and {Zhai}, C. and {Perun}, V.~S. and
{Del Genio}, A. and {Nazarenko}, L.~S. and {Donner}, L.~J. and
{Horowitz}, L. and {Seman}, C. and {Cole}, J. and {Gettelman}, A. and
{Ringer}, M.~A. and {Rotstayn}, L. and {Jeffrey}, S. and {Wu}, T. and
{Brient}, F. and {Dufresne}, J.-L. and {Kawai}, H. and {Koshiro}, T. and
{Watanabe}, M. and {L{\'E}Cuyer}, T.~S. and {Volodin}, E.~M. and
{Iversen}, T. and {Drange}, H. and {Mesquita}, M.~D.~S. and
{Read}, W.~G. and {Waters}, J.~W. and {Tian}, B. and {Teixeira}, J. and
{Stephens}, G.~L.},
title = {{Evaluation of cloud and water vapor simulations in CMIP5 climate models using NASA {\ldquo}A-Train{\rdquo} satellite observations}},
journal = {Journal of Geophysical Research (Atmospheres)},
keywords = {climate model, clouds, satellite observation, water vapor, Global Change: Atmosphere (0315, 0325), Global Change: Global climate models (3337, 4928), Global Change: Remote sensing (1855, 4337), Global Change: Water cycles (1836), Global Change: General or miscellaneous},
year = 2012,
month = jul,
volume = 117,
number = d16,
eid = {D14105},
pages = {14105},
abstract = {{Using NASA's A-Train satellite measurements, we evaluate the accuracy of
cloud water content (CWC) and water vapor mixing ratio (H$_{2}$O)
outputs from 19 climate models submitted to the Phase 5 of Coupled Model
Intercomparison Project (CMIP5), and assess improvements relative to
their counterparts for the earlier CMIP3. We find more than half of the
models show improvements from CMIP3 to CMIP5 in simulating
column-integrated cloud amount, while changes in water vapor simulation
are insignificant. For the 19 CMIP5 models, the model spreads and their
differences from the observations are larger in the upper troposphere
(UT) than in the lower or middle troposphere (L/MT). The modeled mean
CWCs over tropical oceans range from {\tilde}3\% to {\tilde}15{\times} of
the observations in the UT and 40\% to 2{\times} of the observations in
the L/MT. For modeled H$_{2}$Os, the mean values over tropical
oceans range from {\tilde}1\% to 2{\times} of the observations in the UT
and within 10\% of the observations in the L/MT. The spatial
distributions of clouds at 215 hPa are relatively well-correlated with
observations, noticeably better than those for the L/MT clouds. Although
both water vapor and clouds are better simulated in the L/MT than in the
UT, there is no apparent correlation between the model biases in clouds
and water vapor. Numerical scores are used to compare different model
performances in regards to spatial mean, variance and distribution of
CWC and H$_{2}$O over tropical oceans. Model performances at each
pressure level are ranked according to the average of all the relevant
scores for that level.
}},
doi = {10.1029/2011JD017237},
adsurl = {http://adsabs.harvard.edu/abs/2012JGRD..11714105J},
adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2012ACP....12.6185V,
author = {{Verma}, S. and {Boucher}, O. and {Shekar Reddy}, M. and {Upadhyaya}, H.~C. and
{Le Van}, P. and {Binkowski}, F.~S. and {Sharma}, O.~P.},
title = {{Tropospheric distribution of sulphate aerosols mass and number concentration during INDOEX-IFP and its transport over the Indian Ocean: a GCM study}},
journal = {Atmospheric Chemistry \& Physics},
year = 2012,
month = jul,
volume = 12,
pages = {6185-6196},
abstract = {{The sulphate aerosols mass and number concentration during the Indian
Ocean Experiment (INDOEX) Intensive Field Phase-1999 (INDOEX-IFP) has
been simulated using an interactive chemistry GCM. The model considers
an interactive scheme for feedback from chemistry to meteorology with
internally resolving microphysical properties of aerosols. In
particular, the interactive scheme has the ability to predict both
particle mass and number concentration for the Aitken and accumulation
modes as prognostic variables.
On the basis of size
distribution retrieved from the observations made along the cruise route
during IFP-1999, the model successfully simulates the order of magnitude
of aerosol number concentration. The results show the southward
migration of minimum concentrations, which follows ITCZ (Inter Tropical
Convergence Zone) migration. Sulphate surface concentration during
INDOEX-IFP at Kaashidhoo (73.46{\deg} E, 4.96{\deg} N) gives an agreement
within a factor of 2 to 3. The measured aerosol optical depth (AOD) from
all aerosol species at KCO was 0.37 {\plusmn} 0.11 while the model
simulated sulphate AOD ranged from 0.05 to 0.11. As sulphate constitutes
29\% of the observed AOD, the model predicted values of sulphate AOD are
hence fairly close to the measured values. The model thus has capability
to predict the vertically integrated column sulphate burden.
Furthermore, the model results indicate that Indian contribution to the
estimated sulphate burden over India is more than 60\% with values upto
40\% over the Arabian Sea.
}},
doi = {10.5194/acp-12-6185-2012},
adsurl = {http://adsabs.harvard.edu/abs/2012ACP....12.6185V},
adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2012JAtS...69.2090G,
author = {{Grandpeix}, J.-Y. and {Lafore}, J.-P.},
title = {{Reply to ``Comments on `A Density Current Parameterization Coupled with Emanuel's Convection Scheme. Part I: The Models'''}},
journal = {Journal of Atmospheric Sciences},
year = 2012,
month = jun,
volume = 69,
pages = {2090-2096},
doi = {10.1175/JAS-D-11-0127.1},
adsurl = {http://adsabs.harvard.edu/abs/2012JAtS...69.2090G},
adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2012ERL.....7b4013B,
author = {{Boucher}, O. and {Halloran}, P.~R. and {Burke}, E.~J. and {Doutriaux-Boucher}, M. and
{Jones}, C.~D. and {Lowe}, J. and {Ringer}, M.~A. and {Robertson}, E. and
{Wu}, P.},
title = {{Reversibility in an Earth System model in response to CO$_{2}$ concentration changes}},
journal = {Environmental Research Letters},
year = 2012,
month = jun,
volume = 7,
number = 2,
eid = {024013},
pages = {024013},
abstract = {{We use the HadGEM2-ES Earth System model to examine the degree of
reversibility of a wide range of components of the Earth System under
idealized climate change scenarios where the atmospheric CO$_{2}$
concentration is gradually increased to four times the pre-industrial
level and then reduced at a similar rate from several points along this
trajectory. While some modelled quantities respond almost immediately to
the atmospheric CO$_{2}$ concentrations, others exhibit a time lag
relative to the change in CO$_{2}$. Most quantities also exhibit a
lag relative to the global-mean surface temperature change, which can be
described as a hysteresis behaviour. The most surprising responses are
from low-level clouds and ocean stratification in the Southern Ocean,
which both exhibit hysteresis on timescales longer than expected. We see
no evidence of critical thresholds in these simulations, although some
of the hysteresis phenomena become more apparent above 2 {\times}
CO$_{2}$ or 3 {\times} CO$_{2}$. Our findings have
implications for the parametrization of climate impacts in integrated
assessment and simple climate models and for future climate studies of
geoengineering scenarios.
}},
doi = {10.1088/1748-9326/7/2/024013},
adsurl = {http://adsabs.harvard.edu/abs/2012ERL.....7b4013B},
adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2012AMT.....5.1459R,
author = {{Rossignol}, S. and {Chiappini}, L. and {Perraudin}, E. and
{Rio}, C. and {Fable}, S. and {Valorso}, R. and {Doussin}, J.~F.
},
title = {{Development of a parallel sampling and analysis method for the elucidation of gas/particle partitioning of oxygenated semi-volatile organics: a limonene ozonolysis study}},
journal = {Atmospheric Measurement Techniques},
year = 2012,
month = jun,
volume = 5,
pages = {1459-1489},
abstract = {{The gas/particle partitioning behaviour of the semi-volatile fraction of
secondary organic matter and the associated multiphase chemistry are key
features to accurately evaluate climate and health impacts of secondary
organic aerosol (SOA). However, today, the partitioning of oxygenated
secondary species is rarely assessed in experimental SOA studies and SOA
modelling is still largely based on estimated partitioning data. This
paper describes a new analytical approach, solvent-free and easy to use,
to explore the chemical composition of the secondary organic matter at a
molecular scale in both gas and particulate phases. The method is based
on thermal desorption (TD) of gas and particulate samples, coupled with
gas chromatography (GC) and mass spectrometry (MS), with derivatisation
on sampling supports. Gaseous compounds were trapped on Tenax TA
adsorbent tubes pre-coated with pentafluorobenzylhydroxylamine (PFBHA)
or N-Methyl-N-(t-butyldimethylsilyl)trifluoroacetamide (MTBSTFA).
Particulate samples were collected onto quartz or Teflon-quartz filters
and subsequently subjected to derivatisation with PFBHA or MTBSTFA
before TD-GC/MS analysis. Method development and validation are
presented for an atmospherically relevant range of organic acids and
carbonyl and hydroxyl compounds. Application of the method to a limonene
ozonolysis experiment conducted in the EUPHORE simulation chamber under
simulated atmospheric conditions of low concentrations of limonene
precursor and relative humidity, provides an overview of the method
capabilities. Twenty-five compounds were positively or tentatively
identified, nine being in both gaseous and particulate phases; and
twelve, among them tricarboxylic acids, hydroxyl dicarboxylic acids and
oxodicarboxylic acids, being detected for the first time.
}},
doi = {10.5194/amt-5-1459-2012},
adsurl = {http://adsabs.harvard.edu/abs/2012AMT.....5.1459R},
adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2012ACP....12.5583D,
author = {{Déandreis}, C. and {Balkanski}, Y. and {Dufresne}, J.~L. and
{Cozic}, A.},
title = {{Radiative forcing estimates of sulfate aerosol in coupled climate-chemistry models with emphasis on the role of the temporal variability}},
journal = {Atmospheric Chemistry \& Physics},
year = 2012,
month = jun,
volume = 12,
pages = {5583-5602},
abstract = {{This paper describes the impact on the sulfate aerosol radiative effects
of coupling the radiative code of a global circulation model with a
chemistry-aerosol module. With this coupling, temporal variations of
sulfate aerosol concentrations influence the estimate of aerosol
radiative impacts. Effects of this coupling have been assessed on net
fluxes, radiative forcing and temperature for the direct and first
indirect effects of sulfate.
The direct effect respond
almost linearly to rapid changes in concentrations whereas the first
indirect effect shows a strong non-linearity. In particular, sulfate
temporal variability causes a modification of the short wave net fluxes
at the top of the atmosphere of +0.24 and +0.22 W m$^{-2}$ for the
present and preindustrial periods, respectively. This change is small
compared to the value of the net flux at the top of the atmosphere
(about 240 W m$^{-2}$). The effect is more important in regions
with low-level clouds and intermediate sulfate aerosol concentrations
(from 0.1 to 0.8 {$\mu$}g (SO$_{4}$) m$^{-3}$ in our model).
The computation of the aerosol direct radiative forcing is
quite straightforward and the temporal variability has little effect on
its mean value. In contrast, quantifying the first indirect radiative
forcing requires tackling technical issues first. We show that the
preindustrial sulfate concentrations have to be calculated with the same
meteorological trajectory used for computing the present ones. If this
condition is not satisfied, it introduces an error on the estimation of
the first indirect radiative forcing. Solutions are proposed to assess
radiative forcing properly. In the reference method, the coupling
between chemistry and climate results in a global average increase of 8\%
in the first indirect radiative forcing. This change reaches 50\% in the
most sensitive regions. However, the reference method is not suited to
run long climate simulations. We present other methods that are simpler
to implement in a coupled chemistry/climate model and that offer the
possibility to assess radiative forcing.
}},
doi = {10.5194/acp-12-5583-2012},
adsurl = {http://adsabs.harvard.edu/abs/2012ACP....12.5583D},
adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2012JGRE..117.0J07M,
author = {{Madeleine}, J.-B. and {Forget}, F. and {Spiga}, A. and {Wolff}, M.~J. and
{Montmessin}, F. and {Vincendon}, M. and {Jouglet}, D. and {Gondet}, B. and
{Bibring}, J.-P. and {Langevin}, Y. and {Schmitt}, B.},
title = {{Aphelion water-ice cloud mapping and property retrieval using the OMEGA imaging spectrometer onboard Mars Express}},
journal = {Journal of Geophysical Research (Planets)},
keywords = {Atmospheric Composition and Structure: Planetary atmospheres (5210, 5405, 5704), Biogeosciences: Remote sensing, Mathematical Geophysics: Spectral analysis (3205, 3280, 4319), Atmospheric Processes: Clouds and aerosols, Planetary Sciences: Solar System Objects: Mars},
year = 2012,
month = may,
volume = 117,
eid = {E00J07},
pages = {0},
abstract = {{Mapping of the aphelion clouds over the Tharsis plateau and retrieval of
their particle size and visible opacity are made possible by the OMEGA
imaging spectrometer aboard Mars Express. Observations cover the period
from MY26 L$_{s}$ = 330{\deg} to MY29 L$_{s}$ = 180{\deg} and
are acquired at various local times, ranging from 8 AM to 6 PM. Cloud
maps of the Tharsis region constructed using the 3.1 {$\mu$}m ice
absorption band reveal the seasonal and diurnal evolution of aphelion
clouds. Four distinct types of clouds are identified: morning hazes,
topographically controlled hazes, cumulus clouds and thick hazes. The
location and time of occurrence of these clouds are analyzed and their
respective formation process is discussed. An inverse method for
retrieving cloud particle size and opacity is then developed and can
only be applied to thick hazes. The relative error of these measurements
is less than 30\% for cloud particle size and 20\% for opacity. Two groups
of particles can be distinguished. The first group is found over flat
plains and is composed of relatively small particles, ranging in size
from 2 to 3.5 {$\mu$}m. The second group is characterized by particle sizes
of {\tilde}5 {$\mu$}m which appear to be quite constant over L$_{s}$ and
local time. It is found west of Ascraeus and Pavonis Mons, and near
Lunae Planum. These regions are preferentially exposed to anabatic
winds, which may control the formation of these particles and explain
their distinct properties. The water ice column is equal to 2.9 pr.{$\mu$}m
on average, and can reach 5.2 pr.{$\mu$}m in the thickest clouds of
Tharsis.
}},
doi = {10.1029/2011JE003940},
adsurl = {http://adsabs.harvard.edu/abs/2012JGRE..117.0J07M},
adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2012Icar..219..358K,
author = {{Kerber}, L. and {Head}, J.~W. and {Madeleine}, J.-B. and {Forget}, F. and
{Wilson}, L.},
title = {{The dispersal of pyroclasts from ancient explosive volcanoes on Mars: Implications for the friable layered deposits}},
journal = {\icarus},
year = 2012,
month = may,
volume = 219,
pages = {358-381},
abstract = {{A number of voluminous, fine-grained, friable deposits have been mapped
on Mars. The modes of origin for these deposits are debated. The
feasibility for an origin by volcanic airfall for the friable deposits
is tested using a global circulation model to simulate the dispersal of
pyroclasts from candidate source volcanoes near each deposit. It is
concluded that the Medusae Fossae Formation and Electris deposits are
easily formed through volcanic processes, and that the Hellas deposits
and south polar pitted deposits could have some contribution from
volcanic sources in specific atmospheric regimes. The Arabia and Argyre
deposits are not well replicated by modeled pyroclast dispersal,
suggesting that these deposits were most likely emplaced by other means.
}},
doi = {10.1016/j.icarus.2012.03.016},
adsurl = {http://adsabs.harvard.edu/abs/2012Icar..219..358K},
adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2012Icar..219...25F,
author = {{Fastook}, J.~L. and {Head}, J.~W. and {Marchant}, D.~R. and
{Forget}, F. and {Madeleine}, J.-B.},
title = {{Early Mars climate near the Noachian-Hesperian boundary: Independent evidence for cold conditions from basal melting of the south polar ice sheet (Dorsa Argentea Formation) and implications for valley network formation}},
journal = {\icarus},
year = 2012,
month = may,
volume = 219,
pages = {25-40},
abstract = {{Currently, and throughout much of the Amazonian, the mean annual surface
temperatures of Mars are so cold that basal melting does not occur in
ice sheets and glaciers and they are cold-based. The documented evidence
for extensive and well-developed eskers (sediment-filled former
sub-glacial meltwater channels) in the south circumpolar Dorsa Argentea
Formation is an indication that basal melting and wet-based glaciation
occurred at the South Pole near the Noachian-Hesperian boundary. We
employ glacial accumulation and ice-flow models to distinguish between
basal melting from bottom-up heat sources (elevated geothermal fluxes)
and top-down induced basal melting (elevated atmospheric temperatures
warming the ice). We show that under mean annual south polar atmospheric
temperatures (-100 {\deg}C) simulated in typical Amazonian climate
experiments and typical Noachian-Hesperian geothermal heat fluxes (45-65
mW/m$^{2}$), south polar ice accumulations remain cold-based. In
order to produce significant basal melting with these typical geothermal
heat fluxes, the mean annual south polar atmospheric temperatures must
be raised from today's temperature at the surface (-100 {\deg}C) to the
range of -50 to -75 {\deg}C. This mean annual polar surface atmospheric
temperature range implies lower latitude mean annual temperatures that
are likely to be below the melting point of water, and thus does not
favor a ''warm and wet'' early Mars. Seasonal temperatures at lower
latitudes, however, could range above the melting point of water,
perhaps explaining the concurrent development of valley networks and
open basin lakes in these areas. This treatment provides an independent
estimate of the polar (and non-polar) surface temperatures near the
Noachian-Hesperian boundary of Mars history and implies a cold and
relatively dry Mars climate, similar to the Antarctic Dry Valleys, where
seasonal melting forms transient streams and permanent ice-covered lakes
in an otherwise hyperarid, hypothermal climate.
}},
doi = {10.1016/j.icarus.2012.02.013},
adsurl = {http://adsabs.harvard.edu/abs/2012Icar..219...25F},
adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2012ACP....12.4585H,
author = {{Huneeus}, N. and {Chevallier}, F. and {Boucher}, O.},
title = {{Estimating aerosol emissions by assimilating observed aerosol optical depth in a global aerosol model}},
journal = {Atmospheric Chemistry \& Physics},
year = 2012,
month = may,
volume = 12,
pages = {4585-4606},
abstract = {{This study estimates the emission fluxes of a range of aerosol species
and one aerosol precursor at the global scale. These fluxes are
estimated by assimilating daily total and fine mode aerosol optical
depth (AOD) at 550 nm from the Moderate Resolution Imaging
Spectroradiometer (MODIS) into a global aerosol model of intermediate
complexity. Monthly emissions are fitted homogenously for each species
over a set of predefined regions. The performance of the assimilation is
evaluated by comparing the AOD after assimilation against the MODIS
observations and against independent observations. The system is
effective in forcing the model towards the observations, for both total
and fine mode AOD. Significant improvements for the root mean square
error and correlation coefficient against both the assimilated and
independent datasets are observed as well as a significant decrease in
the mean bias against the assimilated observations. These improvements
are larger over land than over ocean. The impact of the assimilation of
fine mode AOD over ocean demonstrates potential for further improvement
by including fine mode AOD observations over continents. The
Angstr{\"o}m exponent is also improved in African, European and dusty
stations. The estimated emission flux for black carbon is 15 Tg
yr$^{-1}$, 119 Tg yr$^{-1}$ for particulate organic matter,
17 Pg yr$^{-1}$ for sea salt, 83 TgS yr$^{-1}$ for
SO$_{2}$ and 1383 Tg yr$^{-1}$ for desert dust. They
represent a difference of +45 \%, +40 \%, +26 \%, +13 \% and -39 \%
respectively, with respect to the a priori values. The initial errors
attributed to the emission fluxes are reduced for all estimated species.
}},
doi = {10.5194/acp-12-4585-2012},
adsurl = {http://adsabs.harvard.edu/abs/2012ACP....12.4585H},
adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2012JAMES...412001Z,
author = {{Zhang}, M. and {Bretherton}, C.~S. and {Blossey}, P.~N. and
{Bony}, S. and {Brient}, F. and {Golaz}, J.-C.},
title = {{The CGILS experimental design to investigate low cloud feedbacks in general circulation models by using single-column and large-eddy simulation models}},
journal = {Journal of Advances in Modeling Earth Systems},
keywords = {cloud feedbacks, Atmospheric Composition and Structure: Cloud/radiation interaction, Atmospheric Processes: Clouds and cloud feedbacks, Atmospheric Processes: Global climate models (1626, 4928)},
year = 2012,
month = apr,
volume = 4,
eid = {M12001},
pages = {12001},
abstract = {{A surrogate climate change is designed to investigate low cloud
feedbacks in the northeastern Pacific by using Single Column Models
(SCMs), Cloud Resolving Models (CRMs), and Large Eddy Simulation models
(LES), as part of the CGILS study (CFMIP-GASS Intercomparison of LES and
SCM models). The constructed large-scale forcing fields, including
subsidence and advective tendencies, and their perturbations in the
warmer climate are shown to compare well with conditions in General
Circulation Models (GCMs), but they are free from the impact of any GCM
parameterizations. The forcing fields in the control climate are also
shown to resemble the mean conditions in the ECMWF-Interim Reanalysis.
Applications of the forcing fields in SCMs are presented. It is shown
that the idealized design can offer considerable insight into the
mechanisms of cloud feedbacks in the models. Caveats and advantages of
the design are also discussed.
}},
doi = {10.1029/2012MS000182},
adsurl = {http://adsabs.harvard.edu/abs/2012JAMES...412001Z},
adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2012GeoRL..39.8805T,
author = {{Tremoy}, G. and {Vimeux}, F. and {Mayaki}, S. and {Souley}, I. and
{Cattani}, O. and {Risi}, C. and {Favreau}, G. and {Oi}, M.},
title = {{A 1-year long {$\delta$}$^{18}$O record of water vapor in Niamey (Niger) reveals insightful atmospheric processes at different timescales}},
journal = {\grl},
keywords = {Geochemistry: Stable isotope geochemistry (0454, 4870), Atmospheric Processes: Boundary layer processes, Atmospheric Processes: Climatology (1616, 1620, 3305, 4215, 8408), Atmospheric Processes: Convective processes, Atmospheric Processes: Instruments and techniques},
year = 2012,
month = apr,
volume = 39,
eid = {L08805},
pages = {8805},
abstract = {{We present a 1-year long representative {$\delta$}$^{18}$O record of
water vapor ({$\delta$}$^{18}$O$_{v}$) in Niamey (Niger) using
the Wavelength Scanned-Cavity Ring Down Spectroscopy (WS-CRDS). We
explore how local and regional atmospheric processes influence
{$\delta$}$^{18}$O$_{v}$ variability from seasonal to diurnal
scale. At seasonal scale, {$\delta$}$^{18}$O$_{v}$ exhibits a
W-shape, associated with the increase of regional convective activity
during the monsoon and the intensification of large scale subsidence
North of Niamey during the dry season. During the monsoon season,
{$\delta$}$^{18}$O$_{v}$ records a broad range of
intra-seasonal modes in the 25-40-day and 15-25-day bands
that could be related to the well-known modes of the West African
Monsoon (WAM). Strong {$\delta$}$^{18}$O$_{v}$ modulations are
also seen at the synoptic scale (5-9 days) during winter,
driven by tropical-extra-tropical teleconnections through the
propagation of a baroclinic wave train-like structure and intrusion of
air originating from higher altitude and latitude.
{$\delta$}$^{18}$O$_{v}$ also reveals a significant diurnal
cycle, which reflects mixing process between the boundary layer and the
free atmosphere during the dry season, and records the propagation of
density currents associated with meso-scale convective systems during
the monsoon season.
}},
doi = {10.1029/2012GL051298},
adsurl = {http://adsabs.harvard.edu/abs/2012GeoRL..39.8805T},
adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2012ClDy...38.1675Z,
author = {{Zhang}, H. and {Wang}, Z. and {Wang}, Z. and {Liu}, Q. and
{Gong}, S. and {Zhang}, X. and {Shen}, Z. and {Lu}, P. and {Wei}, X. and
{Che}, H. and {Li}, L.},
title = {{Simulation of direct radiative forcing of aerosols and their effects on East Asian climate using an interactive AGCM-aerosol coupled system}},
journal = {Climate Dynamics},
keywords = {AGCM, Aerosol, Radiative forcing, Climate effects, East Asian monsoon},
year = 2012,
month = apr,
volume = 38,
pages = {1675-1693},
abstract = {{An interactive system coupling the Beijing Climate Center atmospheric
general circulation model (BCC\_AGCM2.0.1) and the Canadian Aerosol
Module (CAM) with updated aerosol emission sources was developed to
investigate the global distributions of optical properties and direct
radiative forcing (DRF) of typical aerosols and their impacts on East
Asian climate. The simulated total aerosol optical depth (AOD), single
scattering albedo, and asymmetry parameter were generally consistent
with the ground-based measurements. Under all-sky conditions, the
simulated global annual mean DRF at the top of the atmosphere was -2.03
W m$^{-2}$ for all aerosols including sulfate, organic carbon
(OC), black carbon (BC), dust, and sea salt; the global annual mean DRF
was -0.23 W m$^{-2}$ for sulfate, BC, and OC aerosols. The
sulfate, BC, and OC aerosols led to decreases of 0.58{\deg} and 0.14 mm
day$^{-1}$ in the JJA means of surface temperature and
precipitation rate in East Asia. The differences of land-sea surface
temperature and surface pressure were reduced in East Asian monsoon
region due to these aerosols, thus leading to the weakening of East
Asian summer monsoon. Atmospheric dynamic and thermodynamic were
affected due to the three types of aerosol, and the southward motion
between 15{\deg}N and 30{\deg}N in lower troposphere was increased, which
slowed down the northward transport of moist air carried by the East
Asian summer monsoon, and moreover decreased the summer monsoon
precipitation in south and east China.
}},
doi = {10.1007/s00382-011-1131-0},
adsurl = {http://adsabs.harvard.edu/abs/2012ClDy...38.1675Z},
adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2012JCli...25.1847B,
author = {{Brachet}, S. and {Codron}, F. and {Feliks}, Y. and {Ghil}, M. and
{Le Treut}, H. and {Simonnet}, E.},
title = {{Atmospheric Circulations Induced by a Midlatitude SST Front: A GCM Study}},
journal = {Journal of Climate},
year = 2012,
month = mar,
volume = 25,
pages = {1847-1853},
doi = {10.1175/JCLI-D-11-00329.1},
adsurl = {http://adsabs.harvard.edu/abs/2012JCli...25.1847B},
adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2012JGRD..117.3106B,
author = {{Berkelhammer}, M. and {Risi}, C. and {Kurita}, N. and {Noone}, D.~C.
},
title = {{The moisture source sequence for the Madden-Julian Oscillation as derived from satellite retrievals of HDO and H$_{2}$O}},
journal = {Journal of Geophysical Research (Atmospheres)},
keywords = {AURA, MJO, Tropical Climate, hydrology, isotopes, Atmospheric Composition and Structure: General or miscellaneous, Geochemistry: Stable isotope geochemistry (0454, 4870), Hydrology: Hydrometeorology, Hydrology: Water budgets},
year = 2012,
month = feb,
volume = 117,
eid = {D03106},
pages = {3106},
abstract = {{A number of competing theories to explain the initiation mechanism,
longevity and propagation characteristics of the Madden-Julian
Oscillation (MJO) have been developed from observational analysis of the
tropical climate and minimal dynamical models. Using the isotopic
composition of atmospheric moisture from paired satellite retrievals of
H$_{2}$O and HDO from the boundary layer and mid troposphere, we
identify the different sources of moisture that feed MJO convection
during its life cycle. These fluxes are then associated with specific
dynamical processes. The HDO/H$_{2}$O isotope ratio data show that
during the early phase of the MJO, the mid-troposphere is dominated by
moisture evaporated from the ocean surface that was transported
vertically undergoing minimal distillation. The contribution from the
evaporative source diminishes during early convective activity but
reappears during the peak of MJO activity along with an isotopically
depleted flux, which is hypothesized to originate from easterly
convergence. The contribution of different moisture sources as shown
from the HDO/H$_{2}$O data is consistent with model results where
the sustaining of deep convection requires a feedback between
convergence, precipitation strength and evaporation. In the wake of an
MJO event, the weak vertical isotopic gradient, depletion in boundary
layer {$\delta$}D and the uniquely moist and depleted vapor in the mid
troposphere all point toward a prominent presence of moisture originated
from rainfall re-evaporation, which confirms the prediction that the
transition from convective to stratiform rains is important to the
moisture budget of the MJO.
}},
doi = {10.1029/2011JD016803},
adsurl = {http://adsabs.harvard.edu/abs/2012JGRD..117.3106B},
adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2012CliPa...8..205S,
author = {{Shi}, C. and {Daux}, V. and {Zhang}, Q.-B. and {Risi}, C. and
{Hou}, S.-G. and {Stievenard}, M. and {Pierre}, M. and {Li}, Z. and
{Masson-Delmotte}, V.},
title = {{Reconstruction of southeast Tibetan Plateau summer climate using tree ring {$\delta$}$^{18}$O: moisture variability over the past two centuries}},
journal = {Climate of the Past},
year = 2012,
month = feb,
volume = 8,
pages = {205-213},
abstract = {{A tree-ring {$\delta$}$^{18}$O chronology of Linzhi spruce, spanning
from AD 1781 to 2005, was developed in Bomi, Southeast Tibetan Plateau
(TP). During the period with instrumental data (AD 1961-2005), this
record is strongly correlated with regional CRU (Climate Research Unit)
summer cloud data, which is supported by a precipitation
{$\delta$}$^{18}$O simulation conducted with the isotope-enabled
atmospheric general circulation model LMDZiso. A reconstruction of a
regional summer cloud index, based upon the empirical relationship
between cloud and diurnal temperature range, was therefore achieved.
This index reflects regional moisture variability in the past 225 yr.
The climate appears drier and more stable in the 20th century than
previously. The drying trend in late 19th century of our reconstruction
is consistent with a decrease in the TP glacier accumulation recorded in
ice cores. An exceptional dry decade is documented in the 1810s,
possibly related to the impact of repeated volcanic eruptions on monsoon
flow.
}},
doi = {10.5194/cp-8-205-2012},
adsurl = {http://adsabs.harvard.edu/abs/2012CliPa...8..205S},
adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2012QJRMS.138...56C,
author = {{Couvreux}, F. and {Rio}, C. and {Guichard}, F. and {Lothon}, M. and
{Canut}, G. and {Bouniol}, D. and {Gounou}, A.},
title = {{Initiation of daytime local convection in a semi-arid region analysed with high-resolution simulations and AMMA observations}},
journal = {Quarterly Journal of the Royal Meteorological Society},
year = 2012,
month = jan,
volume = 138,
pages = {56-71},
doi = {10.1002/qj.903},
adsurl = {http://adsabs.harvard.edu/abs/2012QJRMS.138...56C},
adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
@article{2012ClDy...38..379C,
author = {{Codron}, F.},
title = {{Ekman heat transport for slab oceans}},
journal = {Climate Dynamics},
keywords = {Slab ocean, Ekman, Heat transport},
year = 2012,
month = jan,
volume = 38,
pages = {379-389},
abstract = {{A series of schemes designed to include various representations of the
Ekman-driven heat fluxes in slab-ocean models is introduced. They work
by computing an Ekman mass flux, then deducing heat fluxes by the
surface flow and an opposite deep return flow. The schemes differ by the
computation of the return flow temperature: either diagnosed from the
SST or given by an active second layer. Both schemes conserve energy,
and use as few parameters as possible. Simulations in an aquaplanet
setting show that the schemes reproduce well the structure of the
meridional heat transport by the ocean. Compared to a diffusive
slab-ocean, the simulated SST is more flat in the tropics, and presents
a relative minimum at the equator, shifting the ITCZ into the summer
hemisphere. In a realistic setting with continents, the slab model
simulates correctly the mean state in many regions, especially in the
tropics. The lack of other dynamical features, such as barotropic gyres,
means that an optimal mean-state in regions such as the mid-latitudes
will require additional flux corrections.
}},
doi = {10.1007/s00382-011-1031-3},
adsurl = {http://adsabs.harvard.edu/abs/2012ClDy...38..379C},
adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
