Aeolis Research | Publications 2010-2011

2011

Title:	Demonstration of ensemble data assimilation for Mars using DART, MarsWRF, and radiance observations from MGS TES
Authors:	Lee, C.; Lawson, W. G.; Richardson, M. I.; Anderson, J. L.; Collins, N.; Hoar, T.; Mischna, M.
Affiliation:	AA(Ashima Research, Pasadena, California, USA); AB(Point Carbon, Washington, D. C., USA); AC(Ashima Research, Pasadena, California, USA); AD(Institute for Mathematics Applied to Geosciences, National Center for Atmospheric Research, Boulder, Colorado, USA); AE(Institute for Mathematics Applied to Geosciences, National Center for Atmospheric Research, Boulder, Colorado, USA); AF(Institute for Mathematics Applied to Geosciences, National Center for Atmospheric Research, Boulder, Colorado, USA); AG(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA)
Journal:	Journal of Geophysical Research, Volume 116, Issue E11, CiteID E11011
Publication Date:	Nov 2011
Origin:	AGU
Keywords:	Global Change: Global climate models (3337, 4928), Informatics: Community modeling frameworks, Informatics: Data assimilation, integration and fusion, Mathematical Geophysics: Numerical approximations and analysis (4260), Planetary Sciences: Solar System Objects: Mars
Abstract Copyright:	(c) 2011: American Geophysical Union
DOI:	http://dx.doi.org/10.1029/2011JE003815 http://bit.ly/Yknr7L
Bibliographic Code:	2011JGRE..11611011L
Abstract:	We describe a global atmospheric data assimilation scheme that has been adapted for use with a Martian General Circulation Model (GCM), with the ultimate goal of creating globally and temporally interpolated “reanalysis” data sets from planetary atmospheric observations. The system uses the Data Assimilation Research Testbed (DART) software to apply an Ensemble Kalman Filter (EnKF) to the MarsWRF GCM. Specific application to Mars also required the development of a radiance forward model for near-nadir Thermal Emission Spectrometer (TES) observations. Preliminary results from an assimilation of 40 sols of TES radiance data, taken around Ls = 150° (August 1999, Mars Year 24), are provided. 1.3 million TES observations are ingested and used to improve the state prediction by the GCM, with bias and error reductions obtained throughout the state vector. Results from the assimilation suggest steepening of the latitudinal and vertical thermal gradients with concurrent strengthening of the mid-latitude zonal jets, and a slower recession of the southern polar ice edge than predicted by the unaided GCM. Limitations of the prescribed dust model are highlighted by the presence of an atmospheric radiance bias. Preliminary results suggest the prescribed dust vertical profile might not be suitable for all seasons, in accordance with more recent observations of the vertical distribution of dust by the Mars Climate Sounder.

Title:	Curvilinear features in the southern hemisphere observed by Mars Global Surveyor Mars Orbiter Camera
Authors:	Wang, Huiqun; Toigo, Anthony D.; Richardson, Mark I.
Affiliation:	AA(Atomic and Molecular Physics, Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA), AB(Center for Radiophysics and Space Research, 326 Space Sciences Building, Cornell University, Ithaca, NY 14853, USA; Present address: Johns Hopkins University, Applied Physics Laboratory, Laurel, MD 20723, USA.), AC(Ashima Research, Pasadena, CA 91106, USA)
Journal:	Icarus, Volume 215, Issue 1, p. 242-252.
Publication Date:	Sep 2011
Origin:	ELSEVIER
Abstract Copyright:	(c) 2011 Elsevier Inc.
DOI:	http://dx.doi.org/10.1016/j.icarus.2011.06.029 http://bit.ly/SlVc57
Bibliographic Code:	2011Icar..215..242W
Abstract:	We have used the complete set of Mars Global Surveyor (MGS) Mars Daily Global Maps (MDGMs) to study martian weather in the southern hemisphere, focusing on curvilinear features, including frontal events and streaks. "Frontal events" refer to visible events that are morphologically analogous to terrestrial baroclinic storms. MDGMs show that visible frontal events were mainly concentrated in the 210-300°E (60-150°W) sector and the 0-60°E sector around the southern polar cap during L s = 140-250° and L s = 340-60°. The non-uniform spatial and temporal distributions of activity were also shown by MGS Thermal Emission Spectrometer transient temperature variations near the surface. "Streaks" refer to long curvilinear features in the polar hood or over the polar cap. They are an indicator of the shape of the polar vortex. Streaks in late winter usually show wavy segments between the 180° meridian and Argyre. Model results suggest that the zonal wave number m = 3 eastward traveling waves are important for their formation.

Title:	Stratospheric superrotation in the TitanWRF model
Authors:	Newman, Claire E.; Lee, Christopher; Lian, Yuan; Richardson, Mark I.; Toigo, Anthony D.
Affiliation:	AA(Ashima Research, Suite 104, 600 South Lake Avenue, Pasadena, CA 91106, USA), AB(Ashima Research, Suite 104, 600 South Lake Avenue, Pasadena, CA 91106, USA), AC(Ashima Research, Suite 104, 600 South Lake Avenue, Pasadena, CA 91106, USA), AD(Ashima Research, Suite 104, 600 South Lake Avenue, Pasadena, CA 91106, USA), AE(The Johns Hopkins University, Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723, USA)
Journal:	Icarus, Volume 213, Issue 2, p. 636-654.
Publication Date:	Jun 2011
Origin:	ELSEVIER
Abstract Copyright:	Elsevier Inc.
DOI:	http://dx.doi.org/10.1016/j.icarus.2011.03.025 http://bit.ly/TZAPqA
Bibliographic Code:	2011Icar..213..636N
Abstract:	TitanWRF general circulation model simulations performed without sub-grid-scale horizontal diffusion of momentum produce roughly the observed amount of superrotation in Titan's stratosphere. We compare these results to Cassini-Huygens measurements of Titan's winds and temperatures, and predict temperature and winds at future seasons. We use angular momentum and transformed Eulerian mean diagnostics to show that equatorial superrotation is generated during episodic angular momentum 'transfer events' during model spin-up, and maintained by similar (yet shorter) events once the model has reached steady state. We then use wave and barotropic instability analysis to suggest that these transfer events are produced by barotropic waves, generated at low latitudes then propagating poleward through a critical layer, thus accelerating low latitudes while decelerating the mid-to-high latitude jet in the late fall through early spring hemisphere. Finally, we identify the dominant waves responsible for the transfers of angular momentum close to northern winter solstice during spin-up and at steady state. Problems with our simulations include peak latitudinal temperature gradients and zonal winds occurring ˜60 km lower than observed by Cassini CIRS, and no reduction in zonal wind speed around 80 km, as was observed by Huygens. While the latter may have been due to transient effects (e.g. gravity waves), the former suggests that our low (˜420 km) model top is adversely affecting the circulation near the jet peak, and/or that we require active haze transport in order to correctly model heating rates and thus the circulation. Future work will include running the model with a higher top, and including advection of a haze particle size distribution.

Title:	A Discrete Ordinate, Multiple Scattering, Radiative Transfer Model of the Venus Atmosphere from 0.1 to 260μm
Authors:	Lee, Christopher; Richardson, Mark Ian
Journal:	Journal of the Atmospheric Sciences, vol. 68, issue 6, pp. 1323-1339
Publication Date:	Jun 2011
Origin:	CROSSREF
DOI:	http://dx.doi.org/10.1175/2011JAS3703.1 http://bit.ly/Qm4a2E
Bibliographic Code:	2011JAtS...68.1323L
Abstract:	Not Available

Title:	The vertical distribution of dust in the Martian atmosphere during northern spring and summer: Observations by the Mars Climate Sounder and analysis of zonal average vertical dust profiles
Authors:	Heavens, N. G.; Richardson, M. I.; Kleinböhl, A.; Kass, D. M.; McCleese, D. J.; Abdou, W.; Benson, J. L.; Schofield, J. T.; Shirley, J. H.; Wolkenberg, P. M.
Affiliation:	AA(Division of the Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, USA), AB(Ashima Research, Pasadena, California, USA), AC(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA), AD(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA), AE(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA), AF(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA), AG(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA), AH(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA), AI(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA), AJ(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA)
Journal:	Journal of Geophysical Research, Volume 116, Issue E4, CiteID E04003
Publication Date:	Apr 2011
Origin:	AGU
Keywords:	Planetary Sciences: Solar System Objects: Mars, Atmospheric Composition and Structure: Aerosols and particles (0345, 4801, 4906), Atmospheric Composition and Structure: Planetary atmospheres (5210, 5405, 5704), Atmospheric Processes: General circulation (1223), Atmospheric Processes: Global climate models (1626, 4928)
Abstract Copyright:	(c) 2011: American Geophysical Union
DOI:	http://dx.doi.org/10.1029/2010JE003691 http://bit.ly/Re6Fp0
Bibliographic Code:	2011JGRE..116.4003H
Abstract:	The vertical distribution of dust in Mars's atmosphere is a critical and poorly known input in atmospheric physical and chemical models and a source of insight into the lifting and transport of dust and general vertical mixing in the atmosphere. We investigate vertical profiles of dust opacity retrieved from limb observations by Mars Climate Sounder during the relatively dust-clear Martian northern summer of 2006-2007 (Ls = 111°-177°of Mars year (MY) 28) and Martian northern spring and summer of 2007-2008 (Ls = 0°-180° of MY 29). To represent local maxima in inferred mass mixing ratio in these profiles, we develop an empirical alternative to the classic “Conrath profile” for representing the vertical distribution of dust in the Martian atmosphere. We then assess the magnitude and variability of atmospheric dust loading, the depth of dust penetration during these seasons, and the impact of the observed vertical dust distribution on the radiative forcing of the circulation. During most of northern spring and summer, the dust mass mixing ratio in the tropics has a maximum at 15-25 km above the local surface (the high-altitude tropical dust maximum (HATDM)). The HATDM appears to have increased significantly in magnitude and altitude during middle to late northern summer of MY 29. The HATDM gradually decayed during late summer of MY 28. Interannual variability in the dust distribution during middle to late northern summer may be connected with known interannual variability in tropical dust storm activity.

Title:	Atmospheric modeling of Mars methane surface releases
Authors:	Mischna, Michael A.; Allen, Mark; Richardson, Mark I.; Newman, Claire E.; Toigo, Anthony D.
Affiliation:	AA(Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., M/S 183-401, Pasadena, CA 91109, USA), AB(Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., M/S 183-401, Pasadena, CA 91109, USA; Also, Division of Geological and Planetary Sciences, California Institute of Technology, MC 150-21, 1200 E. California Blvd. Pasadena, CA 91125, USA), AC(Division of Geological and Planetary Sciences, California Institute of Technology, MC 150-21, 1200 E. California Blvd. Pasadena, CA 91125, USA; Present address: Ashima Research, 600 S. Lake Ave, Suite 303, Pasadena, CA 91106, USA), AD(Division of Geological and Planetary Sciences, California Institute of Technology, MC 150-21, 1200 E. California Blvd. Pasadena, CA 91125, USA; Present address: Ashima Research, 600 S. Lake Ave, Suite 303, Pasadena, CA 91106, USA), AE(Cornell University, Department of Astronomy, Ithaca, NY 14853, USA; Present address: The Johns Hopkins University, Applied Physics Laboratory, 11100 Johns Hopkins Rd., Laurel, MD 20723, USA)
Journal:	Planetary and Space Science, Volume 59, Issue 2-3, p. 227-237.
Publication Date:	Feb 2011
Origin:	ELSEVIER
Abstract Copyright:	Elsevier Ltd
DOI:	http://dx.doi.org/10.1016/j.pss.2010.07.005 http://bit.ly/WsimoA
Bibliographic Code:	2011P&SS...59..227M
Abstract:	We utilize the MarsWRF general circulation model (GCM) to address the behavior of gas plumes in the Martian atmosphere, with the specific goal of characterizing the source of the recently identified methane detection in the Martian atmosphere. These observations have been interpreted as the release of methane from localized surface sources with spatial and temporal variabilities. Due to the limited temporal coverage of ground-based observations, we use a GCM to simulate the development of passive atmospheric plumes over relevant timescales. The observations can be reproduced best if the release occurred just before the time of observation—no more than 1-2 sols earlier—and if this release were nearly instantaneous rather than a slow, steady emission. Furthermore, it requires a source region spanning a broad latitudinal range rather than a point emission. While the accuracy of our conclusions about this specific methane release scenario is limited by the uncertainties inherent in GCM simulations of the Martian atmosphere, our findings regarding generalized plume behavior are robust, and illustrate the potential power of numerical modeling for constraining plume source conditions.

Title:	Vertical distribution of dust in the Martian atmosphere during northern spring and summer: High-altitude tropical dust maximum at northern summer solstice
Authors:	Heavens, N. G.; Richardson, M. I.; Kleinböhl, A.; Kass, D. M.; McCleese, D. J.; Abdou, W.; Benson, J. L.; Schofield, J. T.; Shirley, J. H.; Wolkenberg, P. M.
Affiliation:	AA(Division of the Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, USA), AB(Ashima Research, Pasadena, California, USA), AC(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA), AD(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA), AE(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA), AF(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA), AG(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA), AH(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA), AI(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA), AJ(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA)
Journal:	Journal of Geophysical Research, Volume 116, Issue E1, CiteID E01007
Publication Date:	Jan 2011
Origin:	AGU
Keywords:	Planetary Sciences: Solar System Objects: Mars, Atmospheric Composition and Structure: Aerosols and particles (0345, 4801, 4906), Atmospheric Composition and Structure: Planetary atmospheres (5210, 5405, 5704), Atmospheric Processes: Convective processes, Atmospheric Processes: Global climate models (1626, 4928)
Abstract Copyright:	(c) 2011: American Geophysical Union
DOI:	http://dx.doi.org/10.1029/2010JE003692 http://bit.ly/TqKJoP
Bibliographic Code:	2011JGRE..116.1007H
Abstract:	The vertical distribution of dust in Mars' atmosphere is a critical unknown in the simulation of its general circulation and a source of insight into the lifting and transport of dust. Zonal average vertical profiles of dust opacity retrieved by Mars Climate Sounder show that the vertical dust distribution is mostly consistent with Mars general circulation model (GCM) simulations in southern spring and summer but not in northern spring and summer. Unlike the GCM simulations, the mass mixing ratio of dust has a maximum at 15-25 km over the tropics during much of northern spring and summer: the high-altitude tropical dust maximum (HATDM). The HATDM has significant and characteristic longitudinal variability, which it maintains for time scales on the order of or greater than those on which advection, sedimentation, and vertical eddy diffusion would act to eliminate both the longitudinal and vertical inhomogeneity of the distribution. While outflow from dust storms is able to produce enriched layers of dust at altitudes much greater than 25 km, tropical dust storm activity during the period in which the HATDM occurs is likely too rare to support the HATDM. Instead, the lifting of dust by mesoscale circulations over topography, pseudomoist convection due to the solar heating of dust, and scavenging of dust by water ice are all possible drivers of the HATDM.

Title:	Structure and dynamics of the Martian lower and middle atmosphere as observed by the Mars Climate Sounder: 2. Implications of the thermal structure and aerosol distributions for the mean meridional circulation
Authors:	Heavens, N. G.; McCleese, D. J.; Richardson, M. I.; Kass, D. M.; Kleinböhl, A.; Schofield, J. T.
Affiliation:	AA(Division of the Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, USA), AB(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA), AC(Ashima Research, Pasadena, California, USA), AD(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA), AE(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA), AF(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA)
Journal:	Journal of Geophysical Research, Volume 116, Issue E1, CiteID E01010
Publication Date:	Jan 2011
Origin:	AGU
Keywords:	Atmospheric Composition and Structure: Planetary atmospheres (5210, 5405, 5704), Atmospheric Processes: General circulation (1223), Atmospheric Processes: Mesospheric dynamics, Planetary Sciences: Solar System Objects: Mars
Abstract Copyright:	(c) 2011: American Geophysical Union
DOI:	http://dx.doi.org/10.1029/2010JE003713 http://bit.ly/QHfLdU
Bibliographic Code:	2011JGRE..116.1010H
Abstract:	Retrievals of temperature, dust, and water ice from data collected by the Mars Climate Sounder (MCS) on Mars Reconnaissance Orbiter (MRO) illustrate for the first time the seasonal and diurnal variability of both the thermal structure of the middle atmosphere (above 40 km) and also the vertical distribution of aerosols. These retrievals reveal clear signatures of significant mean meridional cells in the middle and lower atmosphere at both the solstices and equinoxes. We investigate the degree to which the lower and middle atmospheric circulations are kinematically coupled and conclude that kinematic coupling is strong in the tropics throughout the year but weak near the pole except during the “polar warming” events associated with dust storm activity.

2010

Title:	THEMIS-VIS observations of clouds in the martian mesosphere: Altitudes, wind speeds, and decameter-scale morphology
Authors:	McConnochie, T. H.; Bell, J. F.; Savransky, D.; Wolff, M. J.; Toigo, A. D.; Wang, H.; Richardson, M. I.; Christensen, P. R.
Affiliation:	AA(Department of Astronomy, University of Maryland, College Park, MD 20742, USA), AB(Department of Astronomy, Cornell University, Ithaca, NY 14853, USA), AC(Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544, USA), AD(Space Science Institute, 4750 Walnut Street, Suite 205, Boulder, CO 80301, USA), AE(Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723, USA), AF(Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138, USA), AG(Division of Geological and Planetary Sciences, California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125, USA; Ashima Research, Pasadena, CA 91106, USA), AH(Department of Geological Sciences, Arizona State University, Tempe, AZ 85287, USA)
Journal:	Icarus, Volume 210, Issue 2, p. 545-565.
Publication Date:	Dec 2010
Origin:	ELSEVIER
Abstract Copyright:	(c) 2010 Elsevier Inc.
DOI:	http://dx.doi.org/10.1016/j.icarus.2010.07.021 http://bit.ly/V2I0iR
Bibliographic Code:	2010Icar..210..545M
Abstract:	We present measurements of the altitude and eastward velocity component of mesospheric clouds in 35 imaging sequences acquired by the Mars Odyssey (ODY) spacecraft's Thermal Emission Imaging System visible imaging subsystem (THEMIS-VIS). We measure altitude by using the parallax drift of high-altitude features, and the velocity by exploiting the time delay in the THEMIS-VIS imaging sequence. We observe two distinct classes of mesospheric clouds: equatorial mesospheric clouds observed between 0° and 180° Ls; and northern mid-latitude clouds observed only in twilight in the 200-300° Ls period. The equatorial mesospheric clouds are quite rare in the THEMIS-VIS data set. We have detected them in only five imaging sequences, out of a total of 2048 multi-band equatorial imaging sequences. All five fall between 20° south and 0° latitude, and between 260° and 295° east longitude. The mid-latitude mesospheric clouds are apparently much more common; for these we find 30 examples out of 210 northern winter mid-latitude twilight imaging sequences. The observed mid-latitude clouds are found, with only one exception, in the Acidalia region, but this is quite likely an artifact of the pattern of THEMIS-VIS image targeting. Comparing our THEMIS-VIS images with daily global maps generated from Mars Orbiter Camera Wide Angle (MOC-WA) images, we find some evidence that some mid-latitude mesospheric cloud features correspond to cloud features commonly observed by MOC-WA. Comparing the velocity of our mesospheric clouds with a GCM, we find good agreement for the northern mid-latitude class, but also find that the GCM fails to match the strong easterly winds measured for the equatorial clouds. Applying a simple radiative transfer model to some of the equatorial mesospheric clouds, we find good model fits in two different imaging sequences. By using the observed radiance contrast between cloud and cloud-free regions at multiple visible-band wavelengths, these fits simultaneously constrain the optical depths and particles sizes of the clouds. The particle sizes are constrained primarily by the relative contrasts at the available wavelengths, and are found to be quite different in the two imaging sequences: reff = 0.1 μm and reff = 1.5 μm. The optical depths (constrained by the absolute contrasts) are substantial: 0.22 and 0.5, respectively. These optical depths imply a mass density that greatly exceeds the saturated mass density of water vapor at mesospheric temperatures, and so the aerosol particles are probably composed mainly of CO 2 ice. Our simple radiative transfer model is not applicable to twilight, when the mid-latitude mesospheric clouds were observed, and so we leave the properties of these clouds as a question for further work.

Title:	Structure and dynamics of the Martian lower and middle atmosphere as observed by the Mars Climate Sounder: Seasonal variations in zonal mean temperature, dust, and water ice aerosols
Authors:	McCleese, D. J.; Heavens, N. G.; Schofield, J. T.; Abdou, W. A.; Bandfield, J. L.; Calcutt, S. B.; Irwin, P. G. J.; Kass, D. M.; Kleinböhl, A.; Lewis, S. R.; Paige, D. A.; Read, P. L.; Richardson, M. I.; Shirley, J. H.; Taylor, F. W.; Teanby, N.; Zurek, R. W.
Affiliation:	AA(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA), AB(Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, USA), AC(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA), AD(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA), AE(Department of Atmospheric Sciences, University of Washington, Seattle, Washington, USA), AF(Department of Physics, University of Oxford, Oxford, UK), AG(Department of Physics, University of Oxford, Oxford, UK), AH(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA), AI(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA), AJ(Department of Physics and Astronomy, Open University, Milton Keynes, UK), AK(Department of Earth and Space Sciences, University of California, Los Angeles, California, USA), A! L(Department of Physics, University of Oxford, Oxford, UK), AM(Ashima Research, Pasadena, California, USA), AN(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA), AO(Department of Physics, University of Oxford, Oxford, UK), AP(Department of Physics, University of Oxford, Oxford, UK), AQ(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA)
Journal:	Journal of Geophysical Research, Volume 115, Issue E12, CiteID E12016
Publication Date:	Dec 2010
Origin:	AGU
Keywords:	Planetary Sciences: Solar System Objects: Mars
Abstract Copyright:	(c) 2010: American Geophysical Union
DOI:	http://dx.doi.org/10.1029/2010JE003677 http://bit.ly/UP05Tl
Bibliographic Code:	2010JGRE..11512016M
Abstract:	The first Martian year and a half of observations by the Mars Climate Sounder aboard the Mars Reconnaissance Orbiter has revealed new details of the thermal structure and distributions of dust and water ice in the atmosphere. The Martian atmosphere is shown in the observations by the Mars Climate Sounder to vary seasonally between two modes: a symmetrical equinoctial structure with middle atmosphere polar warming and a solstitial structure with an intense middle atmosphere polar warming overlying a deep winter polar vortex. The dust distribution, in particular, is more complex than appreciated before the advent of these high (˜5 km) vertical resolution observations, which extend from near the surface to above 80 km and yield 13 dayside and 13 nightside pole-to-pole cross sections each day. Among the new features noted is a persistent maximum in dust mass mixing ratio at 15-25 km above the surface (at least on the nightside) during northern spring and summer. The water ice distribution is very sensitive to the diurnal and seasonal variation of temperature and is a good tracer of the vertically propagating tide.

Title:	Water ice clouds over the Martian tropics during northern summer
Authors:	Heavens, N. G.; Benson, J. L.; Kass, D. M.; Kleinböhl, A.; Abdou, W. A.; McCleese, D. J.; Richardson, M. I.; Schofield, J. T.; Shirley, J. H.; Wolkenberg, P. M.
Affiliation:	AA(Division of the Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, USA), AB(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA), AC(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA), AD(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA), AE(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA), AF(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA), AG(Ashima Research, Pasadena, California, USA), AH(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA), AI(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA), AJ(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA)
Journal:	Geophysical Research Letters, Volume 37, Issue 18, CiteID L18202
Publication Date:	Sep 2010
Origin:	AGU
Keywords:	Planetary Sciences: Solar System Objects: Mars, Atmospheric Composition and Structure: Cloud physics and chemistry, Atmospheric Composition and Structure: Cloud/radiation interaction, Atmospheric Processes: Clouds and cloud feedbacks, Atmospheric Processes: General circulation (1223)
Abstract Copyright:	(c) 2010: American Geophysical Union
DOI:	http://dx.doi.org/10.1029/2010GL044610 http://bit.ly/U8a2us
Bibliographic Code:	2010GeoRL..3718202H
Abstract:	Atmospheric models suggest that infrared heating due to water ice clouds over the tropics of Mars during early northern summer has a significant impact on the thermal structure of the tropics at cloud level and of the middle atmosphere near the south pole. Retrievals from limb observations by the Mars Climate Sounder on Mars Reconnaissance Orbiter during early northern summer show that water ice clouds over the northern tropics are thinner and higher than in published model results. Later in this season, the latitudinal extent, apparent mass mixing ratio (and infrared heating rate), and altitude of nighttime tropical clouds significantly increase, reaching a maximum just before northern fall equinox. Published model results do not show this transition. By underestimating the altitude at which water ice clouds form, models also may underestimate the intensity of the meridional circulation at higher altitudes in the tropics during northern summer.

Title:	Convective instability in the martian middle atmosphere
Authors:	Heavens, N. G.; Richardson, M. I.; Lawson, W. G.; Lee, C.; McCleese, D. J.; Kass, D. M.; Kleinböhl, A.; Schofield, J. T.; Abdou, W. A.; Shirley, J. H.
Affiliation:	AA(Division of Geological and Planetary Sciences, California Institute of Technology, MC 150-21, Pasadena, CA 91125, USA), AB(Division of Geological and Planetary Sciences, California Institute of Technology, MC 150-21, Pasadena, CA 91125, USA; Ashima Research, 600 S. Lake Ave., Pasadena, CA 91106, USA), AC(Division of Geological and Planetary Sciences, California Institute of Technology, MC 150-21, Pasadena, CA 91125, USA), AD(Division of Geological and Planetary Sciences, California Institute of Technology, MC 150-21, Pasadena, CA 91125, USA; Ashima Research, 600 S. Lake Ave., Pasadena, CA 91106, USA), AE(Jet Propulsion Laboratory, California Institute of Technology, Mail Stop 183-501, 4800 Oak Grove Dr., Pasadena, CA 91109, USA), AF(Jet Propulsion Laboratory, California Institute of Technology, Mail Stop 183-501, 4800 Oak Grove Dr., Pasadena, CA 91109, USA), AG(Jet Propulsion Laboratory, California Institute of Technology, Mail Stop 183-501, 4800 Oak Grove Dr! ., Pasadena, CA 91109, USA), AH(Jet Propulsion Laboratory, California Institute of Technology, Mail Stop 183-501, 4800 Oak Grove Dr., Pasadena, CA 91109, USA), AI(Jet Propulsion Laboratory, California Institute of Technology, Mail Stop 183-501, 4800 Oak Grove Dr., Pasadena, CA 91109, USA), AJ(Jet Propulsion Laboratory, California Institute of Technology, Mail Stop 183-501, 4800 Oak Grove Dr., Pasadena, CA 91109, USA)
Journal:	Icarus, Volume 208, Issue 2, p. 574-589.
Publication Date:	Aug 2010
Origin:	ELSEVIER
Abstract Copyright:	(c) 2010 Elsevier Inc.
DOI:	http://dx.doi.org/10.1016/j.icarus.2010.03.023 http://bit.ly/Re7SwA
Bibliographic Code:	2010Icar..208..574H
Abstract:	Dry convective instabilities in Mars's middle atmosphere are detected and mapped using temperature retrievals from Mars Climate Sounder observations spanning 1.5 martian years. The instabilities are moderately frequent in the winter extratropics. The frequency and strength of middle atmospheric convective instability in the northern extratropics is significantly higher in MY 28 than in MY 29. This may have coupled with changes to the northern hemisphere mid-latitude and tropical middle atmospheric temperatures and contributed to the development of the 2007 global dust storm. We interpret these instabilities to be the result of gravity waves saturating within regions of low stability created by the thermal tides. Gravity wave saturation in the winter extratropics has been proposed to provide the momentum lacking in general circulation models to produce the strong dynamically-maintained temperature maximum at 1-2 Pa over the winter pole, so these observations could be a partial control on modeling experiments.

Title:	On the mystery of the perennial carbon dioxide cap at the south pole of Mars
Authors:	Guo, Xin; Richardson, Mark Ian; Soto, Alejandro; Toigo, Anthony
Affiliation:	AA(Planetary Science, Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, USA); AB(Ashima Research, Pasadena, California, USA); AC(Planetary Science, Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, USA); AD(Center for Radiophysics and Space Research, Cornell University, Ithaca, New York, USA)
Journal:	Journal of Geophysical Research, Volume 115, Issue E4, CiteID E04005
Publication Date:	Apr 2010
Origin:	AGU
Keywords:	Atmospheric Composition and Structure: Planetary atmospheres (5210, 5405, 5704), Planetary Sciences: Solar System Objects: Mars, Planetary Sciences: Solid Surface Planets: Polar regions, Planetary Sciences: Solid Surface Planets: Atmospheres (0343, 1060), Planetary Sciences: Solid Surface Planets: Ices
DOI:	http://dx.doi.org/10.1029/2009JE003382 http://bit.ly/Tha6XP
Bibliographic Code:	2010JGRE..11504005G
Abstract:	A perennial ice cap has long been observed near the south pole of Mars. The surface of this cap is predominantly composed of carbon dioxide ice. The retention of a CO2 ice cap results from the surface energy balance of the latent heat, solar radiation, surface emission, subsurface conduction, and atmospheric sensible heat. While models conventionally treat surface CO2 ice using constant ice albedos and emissivities, such an approach fails to predict the existence of a perennial cap. Here we explore the role of the insolation-dependent ice albedo, which agrees well with Viking, Mars Global Surveyor, and Mars Express albedo observations. Using a simple parameterization within a general circulation model, in which the albedo of CO2 ice responds linearly to the incident solar insolation, we are able to predict the existence of a perennial CO2 cap at the observed latitude and only in the southern hemisphere. Further experiments with different total CO2 inventories, planetary obliquities, and surface boundary conditions suggest that the location of the residual cap may exchange hemispheres favoring the pole with the highest peak insolation.

Title:	A general circulation model ensemble study of the atmospheric circulation of Venus
Authors:	Lee, C.; Richardson, M. I.
Affiliation:	AA(Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, USA), AB(Ashima Research, Pasadena, California, USA)
Journal:	Journal of Geophysical Research, Volume 115, Issue E4, CiteID E04002
Publication Date:	Apr 2010
Origin:	AGU
Keywords:	Planetary Sciences: Solar System Objects: Venus, Atmospheric Processes: General circulation (1223), Planetary Sciences: Fluid Planets: Atmospheres (0343, 1060), Planetary Sciences: Solid Surface Planets: Atmospheres (0343, 1060), Planetary Sciences: Solid Surface Planets: Meteorology (3346)
DOI:	http://dx.doi.org/10.1029/2009JE003490 http://bit.ly/Ykrr8j
Bibliographic Code:	2010JGRE..115.4002L
Abstract:	The response of three numerical model dynamical cores to Venus-like forcing and friction is described in this paper. Each dynamical core simulates a super-rotating atmospheric circulation with equatorial winds of 35 ± 10 m/s, maintained by horizontally propagating eddies leaving the equatorial region and inducing a momentum convergence there. We discuss the balance between the mean circulation and eddies with reference to the production of a super-rotating equatorial flow. The balance between the horizontal eddies and vertical eddies in the polar region is discussed and shown to produce an indirect overturning circulation above the jet. The indirect overturning may be related to the observed region of the polar dipole in the Venus atmosphere. Reservoirs of energy and momentum are calculated for each dynamical core and explicit sources and sinks are diagnosed from the general circulation model (GCM). The effect of a strong “sponge layer” damping to rest is compared with eddy damping and found to change significantly the momentum balance within the top “sponge layer” but does not significantly affect the super-rotation of the bulk of the atmosphere. The Lorenz (1955) energy cycle is calculated and the circulation is shown to be dominated by energy conversion between the mean potential energy and mean kinetic energy reservoirs, with barotropic energy conversion between the mean kinetic energy and eddy kinetic energy reservoirs. We suggest modifications to the GCM parameterizations on the basis of our analysis of the atmospheric circulation and discuss the effect of numerical parameterizations on the simulated atmosphere.