2007
| Title: | High-resolution atmospheric observations by the Mars Odyssey Thermal Emission Imaging System |
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| Authors: | Inada, Ai; Richardson, Mark I.; McConnochie, Timothy H.; Strausberg, Melissa J.; Wang, Huiqun; Bell, James F. |
| Affiliation: | AA(California Institute of Technology, M.S. 150-21, 1200 E. California Blvd., Pasadena, CA 91125, USA), AB(California Institute of Technology, M.S. 150-21, 1200 E. California Blvd., Pasadena, CA 91125, USA), AC(NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA), AD(University of California, Los Angeles, 7229 Math Science Bld., Los Angeles, CA 90095-1565, USA), AE(Harvard-Smithsonian Center for Astrophysics, MS-50, 60 Garden Street, Cambridge, MA 02138, USA), AF(Cornell University, Space Sciences Building, Cornell University, Ithaca, NY 14853, USA) |
| Journal: | Icarus, Volume 192, Issue 2, p. 378-395. |
| Publication Date: | Dec 2007 |
| Origin: | ELSEVIER |
| Abstract Copyright: | Elsevier Inc. |
| DOI: | http://dx.doi.org/10.1016/j.icarus.2007.07.020http://bit.ly/YkvC4e |
| Bibliographic Code: | 2007Icar..192..378I |
| Abstract: | High-resolution observations of atmospheric phenomena by the Mars Odyssey Thermal Emission Imaging System (THEMIS) during its first mapping year are presented. An atmospheric campaign was implemented on the basis of previous spacecraft imaging. This campaign, however, proved of limited success. This appears to be due to the late local time of the Odyssey orbit (the locations of activity at 4 6 p.m. appear to be different from those at 2 p.m.). Ironically, images targeting the surface were more useful for study of the atmosphere than those images specifically targeting atmospheric features. While many previously recognized features were found, novel THEMIS observations included persistent clouds in the southern polar layered deposits, dust or condensate plumes on the northern polar layered deposits, dust plumes as constituent parts of local dust storms, and mesospheric clouds. The former two features tend to be aligned parallel and normal to polar troughs, respectively, suggesting a wind system directed normal to troughs and radially outward from the center of the polar deposits. This is consistent with katabatic drainage of air off the polar deposits, analogous to flow off Antarctica. The observation of dust lifting plumes at unprecedented resolution associated with local dust storms not only demonstrates the importance of mean wind stresses (as opposed to dust devils) in initiation of dust storms, but is also seen to be morphologically identical to dust lifting in terrestrial dust storms. As Odyssey moves to earlier local times, we suggest that the atmospheric campaign from the first mapping year be repeated. |
| Title: | PlanetWRF: A General Purpose, Local to Global Numerical Model for Planetary Atmospheric and Climate Dynamics |
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| Authors: | Richardson, M. I.; Toigo, A. D; Newman, C. E. |
| Journal: | Journal of Geophysical Research, Volume 112, Issue E9, CiteID E09001 |
| Publication Date: | Sep 2007 |
| DOI: | http://dx.doi.org/10.1029/2006JE002825http://bit.ly/TmLSvq |
| Abstract: | A new planetary atmospheric numerical model, “planetWRF,” has been developed by modifying the Weather Research and Forecasting (WRF) model. The model has generalized map projection, multiscale, and nesting capabilities, blurring the distinction between global and mesoscale models and enabling investigation of coupling between processes on all scales, including global. The model can also be run in one, two, or three dimensions. The conversion of the dynamical core for global application by altering the map projection grid and the boundary conditions as well as conversion of the physics parameterizations and constants for planetary application are described. Validation of the global dynamical core through use of standard forcing scenarios is presented. Example results from a series of simulations for Mars, Titan, and Venus are shown to demonstrate that the model performs well for a variety of planets and operating modes (microscale, mesoscale, and global scale). |
2006
| Title: | Surface dust redistribution on Mars as observed by the Mars Global Surveyor and Viking orbiters |
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| Authors: | Szwast, Mark A.; Richardson, Mark I.; Vasavada, Ashwin R. |
| Affiliation: | AA(Division of Geological and Planetary Sciences, 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) |
| Journal: | Journal of Geophysical Research, Volume 111, Issue E11, CiteID E11008 |
| Publication Date: | Nov 2006 |
| Origin: | AGU |
| Keywords: | Planetary Sciences: Solar System Objects: Mars, Planetary Sciences: Solid Surface Planets: Atmospheres (0343, 1060), Planetary Sciences: Solid Surface Planets: Meteorology (3346), Planetary Sciences: Solid Surface Planets: Remote sensing, Atmospheric Composition and Structure: Aerosols and particles (0345, 4801, 4906) |
| Abstract Copyright: | (c) 2006: American Geophysical Union |
| DOI: | http://dx.doi.org/10.1029/2005JE002485http://bit.ly/RecyCv |
| Bibliographic Code: | 2006JGRE..11111008S |
| Abstract: | The variation of surface dust coverage on Mars is mapped using Mars Global Surveyor (MGS) and Viking albedo data. Albedo is shown to correlate well with spectrally derived measurements of surface dust abundance and is subsequently used to gauge dust coverage. Atmospheric aerosols modify the albedo observed from orbit, complicating this analysis. However, opacity cycles are highly repeatable, and simultaneous, independent records of aerosol opacities are available to isolate their impact. The MGS albedo and imaging data contain global coverage on a daily basis, allowing the relationship between dust cover and specific meteorological events to be elucidated. The 2001 global dust storm produced the largest changes in surface dust coverage during the MGS mission. Other processes yielding significant changes include seasonal cap-edge winds, seasonally varying regional winds, local/regional dust storms, and extratropical cyclones. Dust devils and ongoing, small-scale dust lifting do not appear to significantly modify the global patterns of dust cover. Finally, we show that the apparent long-term darkening of the southern mid and high latitudes between the Viking and MGS eras is largely a consequence of the timing of image acquisition relative to global dust storms and surface dust ``cleaning'' by the seasonal ice cap; it does not represent a steady decadal-scale, secular change. In fact, following the 2001 global dust storm, in late southern spring, the southern hemisphere was brighter in MGS than in Viking data. This study reveals albedo to be a dynamic, climatological variable for Mars, similar to sea-surface temperature for terrestrial meteorology and climate. |
| Title: | Simulation of spontaneous and variable global dust storms with the GFDL Mars GCM |
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| Authors: | Basu, Shabari; Wilson, John; Richardson, Mark; Ingersoll, Andrew |
| Affiliation: | AA(Department of Atmospheric Science, Texas A&M University, College Station, Texas, USA); AB(Geophysical Fluid Dynamics Laboratory, National Oceanic and Atmospheric Administration, Princeton, New Jersey, USA); AC(Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, USA); AD(Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, USA) |
| Journal: | Journal of Geophysical Research, Volume 111, Issue E9, CiteID E09004 |
| Publication Date: | Sep 2006 |
| Origin: | AGU |
| Keywords: | Atmospheric Composition and Structure: Planetary atmospheres (5210, 5405, 5704), Global Change: Atmosphere (0315, 0325), Global Change: Climate dynamics (0429, 3309), Global Change: Global climate models (3337, 4928), Global Change: Land/atmosphere interactions (1218, 1843, 3322) |
| Abstract Copyright: | (c) 2006: American Geophysical Union |
| DOI: | http://dx.doi.org/10.1029/2005JE002660http://bit.ly/TqQkf0 |
| Bibliographic Code: | 2006JGRE..11109004B |
| Abstract: | We report on the successful simulation of global dust storms in a general circulation model. The simulated storms develop spontaneously in multiyear simulations and exhibit significant interannual variability. The simulated storms produce dramatic increases in atmospheric dustiness, global-mean air temperatures, and atmospheric circulation intensity, in accord with observations. As with observed global storms, spontaneous initiation of storms in the model occurs in southern spring and summer, and there is significant interannual variability in storm development: years with no storms are interspersed with years with storms of various sizes and specific seasonal date of initiation. Our results support the idea that variable and spontaneous global dust storm behavior can emerge from a periodically forced system (the only forcing being the diurnal and seasonal cycles) when the dust injection mechanism involves an activation threshold. In our simulations, surface wind stresses associated with resolved, large-scale (>300 km) wind systems initiate the storms. These winds are generally associated with the seasonally migrating CO2 cap boundary and sloping topography of the Hellas basin, thermal tides, and traveling waves. A very limited number of large storms begin with lifting along the frontal zones associated with traveling waves in the northern hemisphere. Explosive growth to global scales results from the intensification of the Hadley circulation and the activation of secondary dust-lifting centers. |