2005
| Title: | Relationship between frontal dust storms and transient eddy activity in the northern hemisphere of Mars as observed by Mars Global Surveyor |
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| Authors: | Wang, Huiqun; Zurek, Richard W.; Richardson, Mark I. |
| Affiliation: | AA(Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, USA); AB(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA); AC(Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, USA) |
| Journal: | Journal of Geophysical Research, Volume 110, Issue E7, CiteID E07005 |
| Publication Date: | Jul 2005 |
| Origin: | AGU |
| Keywords: | Planetary Sciences: Solid Surface Planets: Atmospheres (0343, 1060), Planetary Sciences: Solar System Objects: Mars |
| Abstract Copyright: | (c) 2005: American Geophysical Union |
| DOI: | http://dx.doi.org/10.1029/2005JE002423http://bit.ly/Sm1cee |
| Bibliographic Code: | 2005JGRE..11007005W |
| Abstract: | We have compiled a catalog of frontal dust storms in the northern hemisphere using Mars Orbiter Camera daily global maps spanning ~2.3 Martian years of Mars Global Surveyor (MGS) observations (from 1999 to 2003). The most vigorous frontal storms that flush dust to the low latitudes occur in early-mid fall and mid-late winter, away from the northern winter solstice. While many streaks are observed in the polar hood during the winter solstice period, no frontal dust storms are observed in the vicinity of the north polar region. We have also analyzed simultaneous MGS Thermal Emission Spectrometer (TES) temperature data and found statistically significant negative temperature anomalies associated with frontal storms. In the lowest scale height of the atmosphere, the geographical and seasonal distributions of temperature standard deviations associated with transient variations agree well with the distributions of frontal storms. The correlation deteriorates with increasing altitude, suggesting that lower-level temperature waves are associated with the frontal dust storms. Specifically, eastward traveling m = 3 waves with periods of 2-3 sols appear to be closely related to the development of flushing frontal storms. |
| Title: | Aeolian processes in Proctor Crater on Mars: Mesoscale modeling of dune-forming winds |
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| Authors: | Fenton, Lori K.; Toigo, Anthony D.; Richardson, Mark I. |
| Affiliation: | AA(Department of Geology, Arizona State University, Tempe, Arizona, USA); AB(Graduate School of Science and Technology, Kobe University, Kobe, Japan); AC(Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, USA) |
| Journal: | Journal of Geophysical Research, Volume 110, Issue E6, CiteID E06005 |
| Publication Date: | Jun 2005 |
| Origin: | AGU |
| Keywords: | Atmospheric Processes: Planetary meteorology (5445, 5739), Atmospheric Processes: Boundary layer processes, Atmospheric Processes: Climatology (1616, 1620, 3305, 4215, 8408), Planetary Sciences: Solid Surface Planets: Erosion and weathering, Global Change: Geomorphology and weathering (0790, 1824, 1825, 1826, 1886) |
| Abstract Copyright: | (c) 2005: American Geophysical Union |
| DOI: | http://dx.doi.org/10.1029/2004JE002309http://bit.ly/Qm9F1d |
| Bibliographic Code: | 2005JGRE..11006005F |
| Abstract: | Both atmospheric modeling and spacecraft imagery of Mars are now of sufficient quality that the two can be used in conjunction to acquire an understanding of regional- and local-scale aeolian processes on Mars. We apply a mesoscale atmospheric model adapted for use on Mars (the Mars MM5) to Proctor Crater, a 150 km diameter crater in the southern highlands. Proctor Crater contains numerous aeolian features that indicate wind direction, including a large dark dune field with reversing transverse and star dunes containing three different slipface orientations, small and older bright bedforms that are most likely transverse granule ripples, and seasonally erased dust devil tracks. Results from model runs spanning a Martian year, with a horizontal grid spacing of 10 km, predict winds aligned with two of the three dune slipfaces as well as spring and summer winds matching the dust devil track orientations. The primary (most prevalent) dune slipface orientation corresponds to a fall and winter westerly wind created by geostrophic forces. The tertiary dune slipface orientation is caused by spring and summer evening katabatic flows down the eastern rim of the crater, influencing only the eastern portion of the crater floor. The dunes are trapped in the crater because the tertiary winds, enhanced by topography, counter transport from the oppositely oriented primary winds, which may have originally carried sand into the crater. The dust devil tracks are caused by light spring and summer westerly winds during the early afternoon caused by planetary rotation. The secondary dune slipface orientation is not predicted by model results from either the Mars MM5 or the Geophysical Fluid Dynamics Laboratory Mars general circulation model. The reason for this is not clear, and the wind circulation pattern that creates this dune slipface is not well constrained. The Mars MM5 model runs do not predict stresses above the saltation threshold for dune sand of the appropriate size and composition. As with previous work, the calculated wind velocities are too low, which may be caused by too large of a grid spacing. |
| Title: | A survey of Martian dust devil activity using Mars Global Surveyor Mars Orbiter Camera images |
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| Authors: | Fisher, Jenny A.; Richardson, Mark I.; Newman, Claire E.; Szwast, Mark A.; Graf, Chelsea; Basu, Shabari; Ewald, Shawn P.; Toigo, Anthony D.; Wilson, R. John |
| 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(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); AE(La Canada High School, La Canada, California, USA); AF(Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, USA); AG(Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, USA); AH(Department of Astronomy, Cornell University, Ithaca, New York, USA); AI(Geophysical Fluid Dynamics Laboratory, Princeton, New Jersey, USA) |
| Journal: | Journal of Geophysical Research, Volume 110, Issue E3, CiteID E03004 |
| Publication Date: | Mar 2005 |
| Origin: | AGU |
| Keywords: | Atmospheric Processes: Convective processes, Planetary Sciences: Solid Surface Planets: Atmospheres (0343, 1060), Planetary Sciences: Solid Surface Planets: Meteorology (3346), Planetary Sciences: Solar System Objects: Dust, Planetary Sciences: Solar System Objects: Mars |
| Abstract Copyright: | (c) 2005: American Geophysical Union |
| DOI: | http://dx.doi.org/10.1029/2003JE002165http://bit.ly/WTgUkh |
| Bibliographic Code: | 2005JGRE..11003004F |
| Abstract: | A survey of dust devils using the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) wide- and narrow-angle (WA and NA) images has been undertaken. The survey comprises two parts: (1) sampling of nine broad regions from September 1997 to July 2001 and (2) a focused seasonal monitoring of variability in the Amazonis region, an active dust devil site, from March 2001 to April 2004. For part 1, dust devils were identified in NA and WA images, and dust devil tracks were identified in NA images. Great spatial variability in dust devil occurrence is highlighted, with Amazonis Planitia being the most active region examined. Other active regions included Cimmerium, Sinai, and Solis. Numerous dust devil tracks, but very few dust devils, were observed in Casius. This may suggest dust devils here occur at local times other than that of the MGS orbit (~2 pm). Alternatively, variations in surface properties may affect the ability of dust devils to leave visible tracks. The seasonal campaign within Amazonis shows a relatively smooth variation of dust devil activity with season, peaking in mid northern summer and falling to zero in southern spring and summer. This pattern of activity correlates well with the boundary layer maximum depth and hence the vigor of convection. Global maps of boundary layer depth and surface temperature do not predict that Amazonis should be especially active, potentially suggesting a role for mesoscale circulations. Measurement of observed dust devils yields heights of up to 8 km and widths in excess of 0.5 km. |
| Title: | Long-term evolution of transient liquid water on Mars |
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| Authors: | Richardson, Mark I.; Mischna, Michael A. |
| Affiliation: | AA(Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, USA); AB(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA) |
| Journal: | Journal of Geophysical Research, Volume 110, Issue E3, CiteID E03003 |
| Publication Date: | Mar 2005 |
| Origin: | AGU |
| Keywords: | Planetary Sciences: Solar System Objects: Mars, Planetary Sciences: Solid Surface Planets: Erosion and weathering, Planetary Sciences: Solid Surface Planets: Atmospheres (0343, 1060), Atmospheric Composition and Structure: Planetary atmospheres (5210, 5405, 5704), Atmospheric Processes: Paleoclimatology (0473, 4900) |
| Abstract Copyright: | (c) 2005: American Geophysical Union |
| DOI: | http://dx.doi.org/10.1029/2004JE002367http://bit.ly/QHmfcR |
| Bibliographic Code: | 2005JGRE..11003003R |
| Abstract: | Liquid water is not currently stable on the surface of Mars; however, transient liquid water (ice melt) may occur if the surface temperature is between the melting and boiling points. Such conditions are met on Mars with current surface pressures and obliquity due to the large diurnal range of surface temperatures. This yields the potential for transient, nonequilibrium liquid water. A general circulation model is used to undertake an initial exploration of the variation of this ``transient liquid water potential'' (TLWP) for different obliquities and over a range of increased pressures representing progressively earlier phases of Martian geological history. At higher obliquities and slightly higher surface pressures (<50 mbar), TLWP conditions are met over a very large fraction of the planet. As the surface pressure is increased above about 50-100 mbar, however, increased atmospheric thermal blanketing reduces the diurnal surface temperature range, essentially eliminating the possibility of even transient liquid water. At high enough pressures, the mean temperature is sufficiently elevated to allow stable liquid water. Thus the potential for liquid water on Mars has not decreased monotonically over planetary history as the atmosphere was lost. Instead, a distinct minimum in TLWP (the ``dead zone'') will have occurred during the extended period for which pressures were in the middle range between about 0.1 and 1 bar. This has direct and restrictive implications for chemical weathering and life. The fundamental conclusion of this study is largely insensitive to invocation of brines and to more detailed treatment of atmospheric radiative processes. |
| Title: | Observations of the initiation and evolution of the 2001 Mars global dust storm |
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| Authors: | Strausberg, Melissa J.; Wang, Huiqun; Richardson, Mark I.; Ewald, Shawn P.; Toigo, Anthony D. |
| 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(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); AE(Center for Radiophysics and Space Research, Cornell University, Ithaca, New York, USA) |
| Journal: | Journal of Geophysical Research, Volume 110, Issue E2, CiteID E02006 |
| Publication Date: | Feb 2005 |
| Origin: | AGU |
| Keywords: | Planetary Sciences: Solar System Objects: Mars, Planetary Sciences: Solid Surface Planets: Meteorology (3346), Planetary Sciences: Solid Surface Planets: Remote sensing, Planetary Sciences: Solid Surface Planets: Atmospheres (0343, 1060) |
| Abstract Copyright: | (c) 2005: American Geophysical Union |
| DOI: | http://dx.doi.org/10.1029/2004JE002361http://bit.ly/TZFjgN |
| Bibliographic Code: | 2005JGRE..11002006S |
| Abstract: | A global dust storm occurred on Mars between June and October 2001. The storm began near Hellas just before southern spring equinox (~Ls = 177°). Local storms, likely forced by a combination of slope-flow and ice cap thermal contrasts, were observed to propagate along the northwestern rim of Hellas, apparently triggering the global storm. Cap-edge storm activity for much of late southern winter was similar in 2001 to one Mars year earlier; however, a very large storm propagated into the basin just after Ls = 177°. Subsequently, the total area of storm activity in 2001 was roughly double that of the previous year. For about 10 days, dust lifting was limited to the Hellas region. As additional storms propagated into Hellas, activity built and extended northward into Syrtis and eastward into Hesperia. It is not clear whether transport or spreading of lifting were of greatest importance for expansion. At Ls = 185° the storm began to spread rapidly to the east, along a line from the southern pole to the northern tropics. Essentially no storm propagation to the west occurred, yielding strong zonal asymmetry of expansion. As the dust storm reached the western edge of Tharsis, secondary dust lifting centers developed in Daedalia and Solis (southeastern Tharsis). Subsequently, the storm rapidly encompassed the planet (by Ls = 193°). Once fully global, the Syria/Solis/Daedalia lifting center appeared to dominate (on the basis of cloud top morphology), with Hellas quiescent. By Ls = 212°, lifting could no longer be discerned. Thereafter, dust haze appeared uniform and diffuse, and decay appeared to have set in. |
| Title: | A reanalysis of water abundances in the Martian atmosphere at high obliquity |
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| Authors: | Mischna, Michael A.; Richardson, Mark I. |
| 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) |
| Journal: | Geophysical Research Letters, Volume 32, Issue 3, CiteID L03201 |
| Publication Date: | Feb 2005 |
| Origin: | AGU |
| Keywords: | Planetary Sciences: Solid Surface Planets: Atmospheres (0343, 1060), Planetary Sciences: Solar System Objects: Mars, Atmospheric Composition and Structure: Planetary atmospheres (5210, 5405, 5704), Atmospheric Processes: Planetary meteorology (5445, 5739), Planetary Sciences: Solid Surface Planets: Polar regions |
| Abstract Copyright: | (c) 2005: American Geophysical Union |
| DOI: | http://dx.doi.org/10.1029/2004GL021865http://bit.ly/V2N1I6 |
| Bibliographic Code: | 2005GeoRL..3203201M |
| Abstract: | We take a new look at expected atmospheric water vapor abundances on Mars during periods of high obliquity using the Geophysical Fluid Dynamics Laboratory Mars General Circulation Model. For the first time, the sublimation and burial of the present-day residual polar caps beneath a sublimation lag is considered as the planet shifts from lower to high (45°) obliquity periods. Following the elimination of the polar deposits, the only sources for atmospheric water at high obliquity are the low latitude ice deposits emplaced prior to elimination of the polar source. Annual average water vapor abundances are predicted to be only ~20-80 prμm during extended periods of high obliquity, one to two orders of magnitude less than previous estimates. This has implications for the climate history of the planet as it suggests that during extended periods of high obliquity, there is not a significant greenhouse warming effect from elevated atmospheric water vapor. |
2004
| Title: | Simulation of the Martian dust cycle with the GFDL Mars GCM |
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| Authors: | Basu, Shabari; Richardson, Mark I.; Wilson, R. John |
| 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(Geophysical Fluid Dynamics Laboratory, National Oceanic and Atmospheric Administration, Princeton, New Jersey, USA) |
| Journal: | Journal of Geophysical Research, Volume 109, Issue E11, CiteID E11006 |
| Publication Date: | Nov 2004 |
| Origin: | AGU |
| Keywords: | Planetology: Solar System Objects: Mars, Planetology: Solid Surface Planets: Meteorology (3346), Planetology: Solid Surface Planets: Atmospheres-structure and dynamics, Meteorology and Atmospheric Dynamics: General circulation, Atmospheric Composition and Structure: Aerosols and particles (0345, 4801) |
| Abstract Copyright: | (c) 2004: American Geophysical Union |
| DOI: | http://dx.doi.org/10.1029/2004JE002243http://bit.ly/UosUaY |
| Bibliographic Code: | 2004JGRE..10911006B |
| Abstract: | The Martian seasonal dust cycle is examined with a general circulation model (GCM) that treats dust as a radiatively and dynamically interactive trace species. Dust injection is parameterized as being due to convective processes (such as dust devils) and model-resolved wind stresses. Size-dependent dust settling, transport by large-scale winds and subgrid scale diffusion, and radiative heating due to the predicted dust distribution are treated. Multiyear Viking and Mars Global Surveyor air temperature data are used to quantitatively assess the simulations. Varying the three free parameters for the two dust injection schemes (rate parameters for the two schemes and a threshold for wind-stress lifting), we find that the highly repeatable northern spring and summer temperatures can be reproduced by the model if the background dust haze is supplied by either convective lifting or by stress lifting with a very low threshold and a low injection rate. Dust injection due to high-threshold, high-rate stress lifting must be added to these to generate spontaneous and variable dust storms. In order to supply the background haze, widespread and ongoing lifting is required by the model. Imaging data provide a viable candidate mechanism for convective lifting, in the form of dust devils. However, observed nonconvective lifting systems (local storms, etc.) appear insufficiently frequent and widespread to satisfy the role. On the basis of the model results and thermal and imaging data, we suggest that the background dust haze on Mars is maintained by convective processes, specifically, dust devils. Combining the convective scheme and high-threshold stress lifting, we obtain a ``best fit'' multiyear simulation, which produces a realistic thermal state in northern spring and summer and, for the first time, spontaneous and interannually variable global dust storms. |