lmd_all1998.bib

@comment{{This file has been generated by bib2bib 1.98}}

@comment{{Command line: /usr/bin/bib2bib --quiet -c 'not journal:"Discussions"' -c 'not journal:"Polymer Science"' -c year=1998 -c $type="ARTICLE" -oc lmd_all1998.txt -ob lmd_all1998.bib ./EMC3all.link.bib}}

@article{1998CRASE.326..677B,
  author = {{Barthelet}, P. and {Bony}, S. and {Braconnot}, P. and {Braun}, A. and 
	{Cariolle}, D. and {Cohen-Solal}, E. and {Dufresne}, J.-L. and 
	{Delecluse}, P. and {Déqué}, M. and {Fairhead}, L. and 
	{Filiberti}, M.-A. and {Forichon}, M. and {Grandpeix}, J.-Y. and 
	{Guilyardi}, E. and {Hqussais}, M.-N. and {Imbard}, M. and {Le Treut}, H. and 
	{Lévy}, C. and {Xin Li}, Z. and {Madec}, G. and {Marquet}, P. and 
	{Marti}, O. and {Planton}, S. and {Terray}, L. and {Thual}, O. and 
	{Valcke}, S.},
  title = {{Simulations couplées globales des changements climatiques associés {\`a} une augmentation de la teneur atmosphérique en CO $_{2}$}},
  journal = {Comptes Rendus de l'Académie des Sciences - Series IIA - Earth and Planetary Science},
  year = 1998,
  month = may,
  volume = 326,
  pages = {677-684},
  abstract = {{Two transient CO $_{2}$ experiments using two coupled general
circulation models developed by the French GASTON group have been
realized using the same methodology. No flux corrections at the air-sea
interface were used in these experiments. The main features of the
present climate are reasonably well captured by both coupled models in
the control simulations, although the biases are not the same, The
transient CO $_{2}$ simulations show a global warming, ranging
between 1.6 and 2.0 {\deg}C at the time of CO $_{2}$ doubling (+ 70
years). These values, and the main geographical characteristics of
climate change, are in agreement with previous studies published by
other research groups, using either flux corrected or non-flux corrected
models.
}},
  doi = {10.1016/S1251-8050(98)80178-X},
  adsurl = {http://adsabs.harvard.edu/abs/1998CRASE.326..677B},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}

@article{1998JCli...11.1883S,
  author = {{Sharma}, O.~P. and {Le Treut}, H. and {Sèze}, G. and {Fairhead}, L. and 
	{Sadourny}, R.},
  title = {{Interannual Variations of Summer Monsoons: Sensitivity to Cloud Radiative Forcing.}},
  journal = {Journal of Climate},
  year = 1998,
  month = aug,
  volume = 11,
  pages = {1883-1905},
  abstract = {{The sensitivity of the interannual variations of the summer monsoons to
imposed cloudiness has been studied with a general circulation model
using the initial conditions prepared from the European Centre for
Medium-Range Forecasts analyses of 1 May 1987 and 1988. The cloud
optical properties in this global model are calculated from
prognostically computed cloud liquid water. The model successfully
simulates the contrasting behavior of these two successive monsoons.
However, when the optical properties of the observed clouds are
specified in the model runs, the simulations show some degradation over
India and its vicinity. The main cause of this degradation is the
reduced land-sea temperature contrast resulting from the radiative
effects of the observed clouds imposed in such simulations. It is argued
that the high concentration of condensed water content of clouds over
the Indian land areas will serve to limit heating of the land, thereby
reducing the thermal contrast that gives rise to a weak Somali jet. A
countermonsoon circulation is, therefore, simulated in the vector
difference field of 850-hPa winds from the model runs with externally
specified clouds. This countermonsoon circulation is associated with an
equatorial heat source that is the response of the model to the
radiative effects of the imposed clouds. Indeed, there are at least two
clear points that can be made: 1) the cloud-SST patterns, together,
affect the interannual variability; and 2) with both clouds and SST
imposed, the model simulation is less sensitive to initial conditions.
Additionally, the study emphasizes the importance of dynamically
consistent clouds developing in response to the dynamical, thermal, and
moist state of the atmosphere during model integrations.
}},
  doi = {10.1175/1520-0442-11.8.1883},
  adsurl = {http://adsabs.harvard.edu/abs/1998JCli...11.1883S},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}

@article{1998JCli...11.1673L,
  author = {{Le Treut}, H. and {Forichon}, M. and {Boucher}, O. and {Li}, Z.-X.
	},
  title = {{Sulfate Aerosol Indirect Effect and CO$_{2}$ Greenhouse Forcing: EquilibriumResponse of the LMD GCM and Associated Cloud Feedbacks.}},
  journal = {Journal of Climate},
  year = 1998,
  month = jul,
  volume = 11,
  pages = {1673-1684},
  abstract = {{The climate sensitivity to various forcings, and in particular to
changes in CO$_{2}$ and sulfate aerosol concentrations, imposed
separately or in a combined manner, is studied with an atmospheric
general circulation model coupled to a simple slab oceanic model. The
atmospheric model includes a rather detailed treatment of warm cloud
microphysics and takes the aerosol indirect effects into account
explicitly, although in a simplified manner. The structure of the model
response appears to be organized at a global scale, with a partial
independence from the geographical structure of the forcing. Atmospheric
and surface feedbacks are likely to explain this feature. In particular
the cloud feedbacks play a very similar role in the CO$_{2}$ and
aerosol experiments, but with opposite sign. These results strengthen
the idea, already apparent from other studies, that, in spite of their
different nature and their different geographical and vertical
distributions, aerosol may have substantially counteracted the climate
effect of greenhouse gases, at least in the Northern Hemisphere, during
the twentieth century. When the effects of the two forcings are added,
the model response is not symmetric between the two hemispheres. This
feature is also consistent with the findings of other modeling groups
and has implications for the detection of future climate changes.
}},
  doi = {10.1175/1520-0442(1998)011<1673:SAIEAC>2.0.CO;2},
  adsurl = {http://adsabs.harvard.edu/abs/1998JCli...11.1673L},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}

@article{1998CRASB.326...33D,
  author = {{Dufresne}, J. and {Fournier}, R. and {Grandpeix}, J.},
  title = {{Méthode de Monte-Carlo par échanges pour le calcul des bilans radiatifs au sein d'une cavité 2D remplie de gaz}},
  journal = {Academie des Sciences Paris Comptes Rendus Serie B Sciences Physiques},
  year = 1998,
  month = jan,
  volume = 326,
  pages = {33-38},
  doi = {10.1016/S1251-8069(97)86950-3},
  adsurl = {http://adsabs.harvard.edu/abs/1998CRASB.326...33D},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}

@article{1998TellB..50..491C,
  author = {{Claquin}, T. and {Schulz}, M. and {Balkanski}, Y. and {Boucher}, O.
	},
  title = {{Uncertainties in assessing radiative forcing by mineral dust}},
  journal = {Tellus Series B Chemical and Physical Meteorology B},
  year = 1998,
  month = nov,
  volume = 50,
  pages = {491},
  abstract = {{The assessment of the climatic effects of an aerosol with a large
variability like mineral dust requires some approximations whose
validity is investigated in this paper. Calculations of direct radiative
forcing by mineral dust (short-wave, long-wave and net) are performed
with a single-column radiation model for two standard cases in clear sky
condition: a desert case and an oceanic case. Surface forcing result
from a large diminution of the short-wave fluxes and of the increase in
down-welling long-wave fluxes. Top of the atmosphere (TOA) forcing is
negative when short-wave backscattering dominates, for instance above
the ocean, and positive when short-wave or long-wave absorption
dominates, which occurs above deserts. We study here the sensitivity of
these mineral forcings to different treatments of the aerosol complex
refractive index and size distribution. We also describe the importance
of the dust vertical profile, ground temperature, emissivity and albedo.
Among these parameters, the aerosol complex refractive index has been
identified as a critical parameter given the paucity and the incertitude
associated with it. Furthermore, the imaginary part of the refractive
index is inadequate if spectrally averaged. Its natural variability
(linked to mineralogical characteristics) lead to variations of up to
{\plusmn} 40\% in aerosol forcing calculations. A proper representation of
the size distribution when modelling mineral aerosols is required since
dust optical properties are very sensitive to the presence of small
particles. In addition we demonstrate that LW forcing imply a
non-negligible sensitivity to the vertical profiles of temperature and
dust, the latter being an important constraint for dust effect
calculations.
}},
  doi = {10.1034/j.1600-0889.1998.t01-2-00007.x},
  adsurl = {http://adsabs.harvard.edu/abs/1998TellB..50..491C},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}

@article{1998JApMe..37.1385C,
  author = {{Chevallier}, F. and {Chéruy}, F. and {Scott}, N.~A. and 
	{Chédin}, A.},
  title = {{A Neural Network Approach for a Fast and Accurate Computation of a Longwave Radiative Budget.}},
  journal = {Journal of Applied Meteorology},
  year = 1998,
  month = nov,
  volume = 37,
  pages = {1385-1397},
  abstract = {{The authors have investigated the possibility of elaborating a new
generation of radiative transfer models for climate studies based on the
neural network technique. The authors show that their neural
network-based model, NeuroFlux, can be used successfully for accurately
deriving the longwave radiative budget from the top of the atmosphere to
the surface. The reliable sampling of the earth's atmospheric situations
in the new version of the TIGR (Thermodynamic Initial Guess Retrieval)
dataset, developed at the Laboratoire de Météorologie
Dynamique, allows for an efficient learning of the neural networks. Two
radiative transfer models are applied to the computation of the
radiative part of the dataset: a line-by-line model and a band model.
These results have been used to infer the parameters of two neural
network-based radiative transfer codes. Both of them achieve an accuracy
comparable to, if not better than, the current general circulation model
radiative transfer codes, and they are much faster. The dramatic saving
of computing time based on the neural network technique (22 times faster
compared with the band model), 10$^{6}$ times faster compared with
the line-by-line model, allows for an improved estimation of the
longwave radiative properties of the atmosphere in general circulation
model simulations.
}},
  doi = {10.1175/1520-0450(1998)037<1385:ANNAFA>2.0.CO;2},
  adsurl = {http://adsabs.harvard.edu/abs/1998JApMe..37.1385C},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}

@article{1998GeoRL..25.4193D,
  author = {{Doutriaux-Boucher}, M. and {Sèze}, G.},
  title = {{Significant changes between the ISCCP C and D cloud climatologies}},
  journal = {\grl},
  keywords = {Atmospheric Composition and Structure: Cloud physics and chemistry, Global Change: Remote sensing, Meteorology and Atmospheric Dynamics: Remote sensing},
  year = 1998,
  volume = 25,
  pages = {4193-4196},
  abstract = {{ We analyse one year of cloud data from the ISCCP C and D datasets. The
two datasets differ by their retrieval algorithms and their definitions
of the cloud types defined from the cloud top pressure and cloud optical
depth. The differences between the two datasets are first described in
terms of the total cloud cover, as well as its repartition in low,
middle, and high level cloudiness. We also project the ISCCP C cloud
classes into the ISCCP D cloud types to circumvent the problem of
different cloud type definitions in the two datasets. The differences
between the two datasets are then also investigated in terms of the most
frequent cloud type.
}},
  doi = {10.1029/1998GL900081},
  adsurl = {http://adsabs.harvard.edu/abs/1998GeoRL..25.4193D},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}

@article{1998JGR...10326025D,
  author = {{Doutriaux-Boucher}, M. and {Pelon}, J. and {Trouillet}, V. and 
	{SèZe}, G. and {Le Treut}, H. and {Flamant}, P. and {Desbois}, M.
	},
  title = {{Simulation of satellite lidar and radiometer retrievals of a general circulation model three-dimensional cloud data set}},
  journal = {\jgr},
  keywords = {Atmospheric Composition and Structure: Cloud physics and chemistry, Meteorology and Atmospheric Dynamics: Remote sensing, Atmospheric Composition and Structure: Instruments and techniques, Global Change: Remote sensing},
  year = 1998,
  month = oct,
  volume = 103,
  pages = {26025},
  abstract = {{The inclusion of a backscatter lidar on a space platform for a radiation
mission, as proposed by various space agencies, aims to bring new
information on three-dimensional cloud distribution, with a special
emphasis on optically thin cirrus clouds, which are presently poorly
detected by passive sensors. Key issues for such cloud observational
studies are the detection of multilayered cloud systems, thin cirrus,
and fractional cloud cover, knowledge that would improve our
understanding of the global radiation budget. To assess the impact of
such lidar measurements on cloud climatology, a 1 month cloud data set
has been simulated with a general circulation model (GCM). The cloud
detection capability of a spaceborne scanning backscatter lidar is
assessed with the use of two detection schemes, one based on limitations
in the detected cloud optical depth and the other based on lidar
signal-to-noise ratio. The cloud information retrieved from passive
radiometric measurements using a procedure like that used in the
International Satellite Cloud Climatology Project is also simulated from
the same GCM cloud data set. It is shown that a spaceborne backscatter
lidar can improve significantly the retrieval of thin cirrus clouds as
well as underlying cloud layers. High-level cloud retrieval from a
spaceborne lidar therefore appears as a powerful complement to
radiometric measurements for improving our knowledge of actual cloud
climatology.
}},
  doi = {10.1029/98JD02378},
  adsurl = {http://adsabs.harvard.edu/abs/1998JGR...10326025D},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}

@article{1998GeoRL..25.3159V,
  author = {{Vanbauce}, C. and {Buriez}, J.~C. and {Parol}, F. and {Bonnel}, B. and 
	{Sèze}, G. and {Couvert}, P.},
  title = {{Apparent pressure derived from ADEOS-POLDER observations in the oxygen A-band over ocean}},
  journal = {\grl},
  keywords = {Atmospheric Composition and Structure: Transmission and scattering of radiation, Atmospheric Composition and Structure: Cloud physics and chemistry, Atmospheric Composition and Structure: Instruments and techniques, Exploration Geophysics: Remote sensing},
  year = 1998,
  volume = 25,
  pages = {3159-3162},
  abstract = {{The POLDER radiometer was on board the ADEOS satellite from August 1996
to June 1997. This instrument measures radiances in eight narrow
spectral bands of the visible and near infrared spectrum. Two of them
are centered on the O$_{2}$ A-band in order to infer cloud
pressure. By assuming the atmosphere behaves as a pure absorbing medium
overlying a perfect reflector, an {\rdquo}apparent{\rdquo} pressure
P$_{app}$ is derived from POLDER data. For validation purposes,
P$_{app}$ is first compared to the sea-surface pressure
P$_{s}$ for clear-sky conditions; P$_{app}$ is found to be
close to P$_{s}$ (within {\sim}30 hPa) for measurements in the
sunglint region. For overcast conditions, P$_{app}$ differs from
the cloud-top pressure mainly because of multiple scattering inside the
cloud. When P$_{app}$ is compared to the cloud pressure determined
from brightness temperature measurements, large differences are observed
(typically 180 hPa).
}},
  doi = {10.1029/98GL02324},
  adsurl = {http://adsabs.harvard.edu/abs/1998GeoRL..25.3159V},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}

@article{1998JPO....28.1346H,
  author = {{Herbaut}, C. and {Codron}, F. and {Crépon}, M.},
  title = {{Separation of a Coastal Current at a Strait Level: Case of the Strait of Sicily}},
  journal = {Journal of Physical Oceanography},
  year = 1998,
  month = jul,
  volume = 28,
  pages = {1346-1362},
  doi = {10.1175/1520-0485(1998)028<1346:SOACCA>2.0.CO;2},
  adsurl = {http://adsabs.harvard.edu/abs/1998JPO....28.1346H},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}

@article{1998JGR...10316979B,
  author = {{Boucher}, O. and {Schwartz}, S.~E. and {Ackerman}, T.~P. and 
	{Anderson}, T.~L. and {Bergstrom}, B. and {Bonnel}, B. and {Ch{\'y}lek}, P. and 
	{Dahlback}, A. and {Fouquart}, Y. and {Fu}, Q. and {Halthore}, R.~N. and 
	{Haywood}, J.~M. and {Iversen}, T. and {Kato}, S. and {Kinne}, S. and 
	{Kirkev{\^a}G}, A. and {Knapp}, K.~R. and {Lacis}, A. and {Laszlo}, I. and 
	{Mishchenko}, M.~I. and {Nemesure}, S. and {Ramaswamy}, V. and 
	{Roberts}, D.~L. and {Russell}, P. and {Schlesinger}, M.~E. and 
	{Stephens}, G.~L. and {Wagener}, R. and {Wang}, M. and {Wong}, J. and 
	{Yang}, F.},
  title = {{Intercomparison of models representing direct shortwave radiative forcing by sulfate aerosols}},
  journal = {\jgr},
  keywords = {Meteorology and Atmospheric Dynamics: Radiative processes, Atmospheric Composition and Structure: Aerosols and particles, Atmospheric Composition and Structure: Transmission and scattering of radiation, Global Change: Atmosphere},
  year = 1998,
  month = jul,
  volume = 103,
  pages = {16979},
  abstract = {{The importance of aerosols as agents of climate change has recently been
highlighted. However, the magnitude of aerosol forcing by scattering of
shortwave radiation (direct forcing) is still very uncertain even for
the relatively well characterized sulfate aerosol. A potential source of
uncertainty is in the model representation of aerosol optical properties
and aerosol influences on radiative transfer in the atmosphere. Although
radiative transfer methods and codes have been compared in the past,
these comparisons have not focused on aerosol forcing (change in net
radiative flux at the top of the atmosphere). Here we report results of
a project involving 12 groups using 15 models to examine radiative
forcing by sulfate aerosol for a wide range of values of particle
radius, aerosol optical depth, surface albedo, and solar zenith angle.
Among the models that were employed were high and low spectral
resolution models incorporating a variety of radiative transfer
approximations as well as a line-by-line model. The normalized forcings
(forcing per sulfate column burden) obtained with the several radiative
transfer models were examined, and the discrepancies were characterized.
All models simulate forcings of comparable amplitude and exhibit a
similar dependence on input parameters. As expected for a
non-light-absorbing aerosol, forcings were negative (cooling influence)
except at high surface albedo combined with small solar zenith angle.
The relative standard deviation of the zenith-angle-averaged normalized
broadband forcing for 15 models was 8\% for particle radius near the
maximum in this forcing ({\tilde}0.2 {$\mu$}m) and at low surface albedo.
Somewhat greater model-to-model discrepancies were exhibited at specific
solar zenith angles. Still greater discrepancies were exhibited at small
particle radii, and much greater discrepancies were exhibited at high
surface albedos, at which the forcing changes sign; in these situations,
however, the normalized forcing is quite small. Discrepancies among the
models arise from inaccuracies in Mie calculations, differing treatment
of the angular scattering phase function, differing wavelength and
angular resolution, and differing treatment of multiple scattering.
These results imply the need for standardized radiative transfer methods
tailored to the direct aerosol forcing problem. However, the relatively
small spread in these results suggests that the uncertainty in forcing
arising from the treatment of radiative forcing of a well-characterized
aerosol at well-specified surface albedo is smaller than some of the
other sources of uncertainty in estimates of direct forcing by
anthropogenic sulfate aerosols and anthropogenic aerosols generally.
}},
  doi = {10.1029/98JD00997},
  adsurl = {http://adsabs.harvard.edu/abs/1998JGR...10316979B},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}

@article{1998TellA..50..302T,
  author = {{Teitelbaum}, H. and {Sadourny}, R.},
  title = {{The r{\^o}le of planetary waves in the formation of polar stratospheric clouds}},
  journal = {Tellus Series A},
  year = 1998,
  month = may,
  volume = 50,
  pages = {302},
  abstract = {{Several recent works attribute the formation of polar stratospheric
clouds (PSCs) to the occurrence of localized orographic waves. Using
ECMWF analyses, we investigate the large scale stratospheric flow
conditions in a number of cases where PSCs have been detected, both in
the Arctic and in the Antarctic. We show that PSCs appear within strong
planetary scale uplifts of isentropic surfaces. The adiabatic cooling of
air parcels travelling within such planetary scale uplifts while
conserving their humidity and trace constituents, seems to be the main
mechanism for PSC formation. The PSC distribution would then follow a
planetary structure, even though local orographic waves could still play
an additional role when planetary scale conditions are met.
}},
  doi = {10.1034/j.1600-0870.1998.t01-2-00004.x},
  adsurl = {http://adsabs.harvard.edu/abs/1998TellA..50..302T},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}

@article{1998A&A...333.1092B;,
  author = {{Billebaud}, F. and {Rosenqvist}, J. and {Lellouch}, E. and 
	{Maillard}, J.-P. and {Encrenaz}, T. and {Hourdin}, F.},
  title = {{Observations of CO in the atmosphere of Mars in the (2-0) vibrational band at 2.35 microns}},
  journal = {\aap},
  keywords = {PLANETS AND SATELLITES: INDIVIDUAL: MARS, INFRARED: SOLAR SYSTEM},
  year = 1998,
  month = may,
  volume = 333,
  pages = {1092-1099},
  abstract = {{Following our high-resolution infrared observations of CO in the
atmosphere of Mars in 1988 and 1989 at 4.7mu m (Billebaud et al., 1992),
we recorded new spectra of CO: one covering the whole disk of the planet
in 1990 and 4 spectra corresponding to 4 different locations on the
planet in 1991. All these spectra were recorded in the (2-0) vibrational
band at 2.35mu m. These data allow us to measure the CO abundance and to
search for possible middle-scale spatial variations of this abundance in
the case of the 1991 spectra. The CO mixing ratio derived from the 1990
data is in good agreement with the values we obtained in 1988 and 1989
(Billebaud et al., 1992), showing a great stability over a period of 3
years, with a value of the CO mixing ratio remaining in the range of
4.2-8.5 x 10(-4) . The results we obtained with the 1991 data also seem
to comfort the stability of the CO mixing ratio, although the possible
range is somewhat larger (5.5-11.5 x 10(-4) ). This common CO mixing
ratio range for the four locations on the planet then tends to exclude
the presence of any significant horizontal variations of the CO mixing
ratio, even if, from our data, we cannot firmly rule them out.
}},
  adsurl = {http://adsabs.harvard.edu/abs/1998A%26A...333.1092B},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}

@article{1998A&AS..129..353L;,
  author = {{Li}, Z.~X.},
  title = {{Measurements of interannual variation of the vertical at Jozefoslaw by astrometric and gravimetric observations}},
  journal = {\aaps},
  keywords = {EARTH, REFERENCE SYSTEMS, ASTROMETRY},
  year = 1998,
  month = apr,
  volume = 129,
  pages = {353-355},
  abstract = {{Jozefoslaw astronomical and geodetical observatory at Warsaw is the
place where parallel observations of astrometric latitude (since 1959)
and meridional plumb line variations from gravimetric methods (since
1976) have been carried out continuously over the past 20 years. The
observational data at this observatory have been analysed to confirm the
reality of the plumb line variation results derived from the astrometric
latitude residuals. Cross correlation analyses between the results of
the two techniques have demonstrated that the interannual plumb line
variations along the meridian detected by the astrometric technique is
in good accordance with those from the gravimetric technique. The
results shown in the paper can be considered as evidence of the
existence of non-tidal plumb line variations at interannual time scales,
of which the scale is about 0.02'' in the case of Jozefoslaw
observatory, and the possibility in measuring them by astrometric
techniques.
}},
  doi = {10.1051/aas:1998190},
  adsurl = {http://adsabs.harvard.edu/abs/1998A%26AS..129..353L},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}

@article{1998Icar..131..302F,
  author = {{Forget}, F. and {Hourdin}, F. and {Talagrand}, O.},
  title = {{CO $_{2}$Snowfall on Mars: Simulation with a General Circulation Model}},
  journal = {\icarus},
  year = 1998,
  month = feb,
  volume = 131,
  pages = {302-316},
  abstract = {{Although CO $_{2}$snowfall has never been directly observed on
Mars, it has been suggested that such precipitation may explain the
puzzling infrared measurements obtained by Mariner 9 and Viking during
the polar night in each hemisphere. The radiative effect of the snow
would strongly alter the radiative balance of the condensing polar caps
and thus the CO $_{2}$cycle and the global climate. We have
simulated this phenomenon with a general circulation model (GCM). For
that purpose, a new parameterization of CO $_{2}$condensation in
the atmosphere and on the ground has been developed, paying particular
attention to mass and energy conservation and allowing for the possible
sublimation of sedimenting CO $_{2}$ice particles. Atmospheric
condensation may result from radiative cooling on the one hand
(especially when the atmosphere is dust laden) and from adiabatic
cooling in upward motions on the other hand. This latter process can be
very efficient locally. On this basis, we have modeled the effect of the
CO $_{2}$snowfall on the infrared emission by decreasing the local
emissivities when atmospheric condensation was predicted by the model.
This parameterization is based on physical considerations (radiative
transfer through the CO $_{2}$ice particles, snow metamorphism on
the ground). Without tuning the model parameters, we have been able to
accurately reproduce the general behavior of the features observed by
Viking in the thermal infrared. These modeling results support the CO
$_{2}$snowfall scenario suggested from the observations. Overall,
this new parameterization, used in combination with the digital terrain
model topography and with allowance for a varying atmospheric dust
content, allows the GCM to simulate the CO
$_{2}$condensation-sublimation cycle realistically. In particular,
the seasonal variations of the surface pressure recorded by the Viking
Landers can now be reproduced without artificially decreasing the
condensation rate as was done in previous studies.
}},
  doi = {10.1006/icar.1997.5874},
  adsurl = {http://adsabs.harvard.edu/abs/1998Icar..131..302F},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}

@article{1998JAtS...55..128B,
  author = {{Boucher}, O.},
  title = {{On Aerosol Direct Shortwave Forcing and the Henyey-Greenstein Phase Function.}},
  journal = {Journal of Atmospheric Sciences},
  year = 1998,
  month = jan,
  volume = 55,
  pages = {128-134},
  abstract = {{This technical note extends previous Mie calculations to show that there
are complex relationships between the asymmetry parameter g and the
upscatter fractions for monodirectional incident radiation
($_{0}$). Except for intermediate zenith angles and for the
upscatter fraction for diffuse radiation, there are significant
differences between ($_{0}$) predicted by the Mie theory and that
approximated by a Henyey-Greenstein phase function. While the
Henyey-Greenstein phase function is widely used in radiative transfer
calculations to characterize aerosol or cloud droplet scattering, it may
cause important discrepancies in the computation of the aerosol direct
radiative forcing, depending on solar zenith angle, aerosol size, and
refractive index. The implications of this work for aerosol and
climate-related studies are also discussed.
}},
  doi = {10.1175/1520-0469(1998)055<0128:OADSFA>2.0.CO;2},
  adsurl = {http://adsabs.harvard.edu/abs/1998JAtS...55..128B},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}

@article{1998ClDy...14..307D,
  author = {{Ducharne}, A. and {Laval}, K. and {Polcher}, J.},
  title = {{Sensitivity of the hydrological cycle to the parametrization of soil hydrology in a GCM}},
  journal = {Climate Dynamics},
  year = 1998,
  volume = 14,
  pages = {307-327},
  abstract = {{The sensitivity of the hydrological cycle to soil hydrology is
investigated with the LMD GCM. The reference simulation includes the
land-surface scheme SECHIBA, with a two-reservoir scheme for soil water
storage and runoff at saturation. We studied a non-linear drainage
parametrization, and a distributed surface runoff parametrization,
accounting for the subgrid scale variability (SSV) of soil moisture
capacity, through a distribution where the shape parameter was b. GCM
results show that the drainage parametrization induces significant
reductions in soil moisture and evaporation rate compared to the
reference simulation. They are related to changes in moisture
convergence in the tropics, and to a precipitation decrease in the
extratropics. When drainage is implemented, the effect of the SSV
parametrization (b=0.2) is also to reduce soil moisture and evaporation
rates compared to the simulation with drainage only. These changes are
much smaller than the former, but the sensitivity of the hydrological
cycle to the SSV parametrization is shown to be larger in dry periods,
and to be enhanced by an increase of the shape parameter b. The
comparison of simulated total runoffs with observed data shows that the
soil hydrological parametrizations does not reduce the GCM systematic
errors in the annual water balance, but that they can improve the
representation of the total runoff's annual cycle.
}},
  doi = {10.1007/s003820050226},
  adsurl = {http://adsabs.harvard.edu/abs/1998ClDy...14..307D},
  adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}