2003
| Title: | Numerical Simulation of Martian Global Dust Storms and the Dust Cycle |
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| Authors: | Basu, S.; Richardson, M. I.; Wilson, J.; Ingersoll, A. P. |
| Affiliation: | AA(Division of Geological and Planetary Sciences, California Institute of Technology, MC 150-21 1200 E. California Blvd, Pasadena, CA 91125 United States; shabari@gps.caltech.edu), AB(Division of Geological and Planetary Sciences, California Institute of Technology, MC 150-21 1200 E. California Blvd, Pasadena, CA 91125 United States; mir@gps.caltech.edu), AC(NOAA/Geophysical Fluid Dynamics Laboratory, P.O. Box 308, Princeton, NJ 08542 United States; rjw@gfdl.noaa.gov), AD(Division of Geological and Planetary Sciences, California Institute of Technology, MC 150-21 1200 E. California Blvd, Pasadena, CA 91125 United States; api@gps.caltech.edu) |
| Journal: | American Geophysical Union, Fall Meeting 2003, abstract #P51C-0456 |
| Publication Date: | Dec 2003 |
| Origin: | AGU |
| Keywords: | 0305 Aerosols and particles (0345, 4801), 3319 General circulation, 5409 Atmospheres: structure and dynamics, 5445 Meteorology (3346), 6225 Mars |
| Abstract Copyright: | (c) 2003: American Geophysical Union |
| Bibliographic Code: | 2003AGUFM.P51C0456B |
| Abstract: | We investigate the triggering, growth, decay and the inter-annual variability of global dust storms (GDS) on Mars. To date, testing of various theories of GDS initiation and variability has been limited by inability to numerically simulate spontaneous, variable storm development from realistic pre-storm model states. Here we describe General Circulation Model simulations that generate spontaneous and variable GDSs from realistic background conditions. Modelled GDSs produce dramatic increases in atmospheric dustiness, global-mean air temperatures, and atmospheric circulation, in accord with observations. The simulations generate global storms in southern spring and summer with significant inter-annual variability in size and timing of occurrence, including years with no storms. We propose a simple explanation for the observed dust cycle on Mars from our simulations. Stresses associated with large-scale (>300 km) wind systems initiate the large storms. Explosive growth results from the intensification of the Hadley circulation and the activation of secondary dust lifting centers. Away from great storms, the annually repeatable cycle of atmospheric temperatures and dust opacities observed in northern spring and summer is a result of convective (dust devil) lifting. |
| Title: | Seasonal Weather Patterns Influencing Dune Morphology in Noachis Terra, Mars: Using a Mesoscale Model for Surface Science |
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| Authors: | Fenton, L. K.; Richardson, M. I.; Toigo, A. D. |
| Affiliation: | AA(Arizona State University, Dept. of Geological Sciences Mail Code 1404, Tempe, AZ 85287 United States; lkfenton@asu.edu), AB(California Institute of Technology, Division of Geological and Planetary Sciences MC 150-21, Pasadena, CA 91125 United States; mir@gps.caltech.edu), AC(Cornell University, Center for Radiophysics and Space Research 326 Space Sciences Building, Ithaca, NY 14853 United States; toigo@astro.cornell.edu) |
| Journal: | American Geophysical Union, Fall Meeting 2003, abstract #P42A-0424 |
| Publication Date: | Dec 2003 |
| Origin: | AGU |
| Keywords: | 5400 PLANETOLOGY: SOLID SURFACE PLANETS, 5407 Atmospheres: evolution, 5445 Meteorology (3346), 5464 Remote sensing, 6225 Mars |
| Abstract Copyright: | (c) 2003: American Geophysical Union |
| Bibliographic Code: | 2003AGUFM.P42A0424F |
| Abstract: | The work of the wind is the one sedimentary process that both acts on the surface and interacts with the lower atmosphere of Mars. Wind-sculpted landforms such as sand dunes are among the few features visible in spacecraft images that provide information on the aeolian sedimentary environment and surface wind circulation patterns of Mars. The study of the placement and orientations of sand dunes leads to the depositional, erosional, and transport history of sand across a region. When correlated with wind predictions from an atmospheric model, dune orientations provide not only model verification but also an understanding of the seasonal weather patterns that influence dune morphology. We have applied a mesoscale model to Noachis Terra, an 1800 km x 3500 km area of Mars containing several dune fields. The Mars Mesoscale Model 5 (Mars MM5), developed from the PSU/NCAR MM5, was run in periods spanning the Martian year, predicting seasonal wind patterns for each of nine dune fields in Noachis Terra. Dune slipface orientations were measured for all dune fields imaged by the Mars Orbiter Camera (MOC) on the Mars Global Surveyor. Preliminary results indicate a high correspondence of dune morphology with present-day seasonally-dependent wind patterns predicted by the Mars MM5. |
| Title: | Obliquity-Driven Volatile Cycling in the Tropics and Mid-Latitudes of Mars. |
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| Authors: | Mischna, M. A.; Richardson, M. I.; McCleese, D. J.; Vasavada, A. R.; Wilson, R. J. |
| Affiliation: | AA(University of California, Los Angeles, Department of Earth and Space Sciences 595 Charles Young Drive East, Los Angeles, CA 90095 United States; California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125 United States; mischna@ucla.edu), AB(California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125 United States; mir@gps.caltech.edu), AC(California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125 United States; daniel.j.mccleese@jpl.nasa.gov), AD(University of California, Los Angeles, Department of Earth and Space Sciences 595 Charles Young Drive East, Los Angeles, CA 90095 United States; ashwin@ess.ucla.edu), AE(Geophysical Fluid Dynamics Laboratory, PO Box 308, Princeton, NJ 08542 United States; rjw@gfdl.noaa.gov) |
| Journal: | American Geophysical Union, Fall Meeting 2003, abstract #P32B-04 |
| Publication Date: | Dec 2003 |
| Origin: | AGU |
| Keywords: | 0343 Planetary atmospheres (5405, 5407, 5409, 5704, 5705, 5707), 1620 Climate dynamics (3309), 3344 Paleoclimatology, 5445 Meteorology (3346), 6225 Mars |
| Abstract Copyright: | (c) 2003: American Geophysical Union |
| Bibliographic Code: | 2003AGUFM.P32B..04M |
| Abstract: | The placement of water within the martian regolith may occur through any of several means, the most important of which appear to be vapor diffusion, surface adsorption and subaerial deposition. In order to understand the relative importance of each of these modes during past periods of higher obliquity, we have linked a vapor and thermal diffusion model to the GFDL Mars GCM, and permitted water (as ice, vapor or adsorbate) to interact freely between the atmosphere and regolith. Our results strive to explain both the unique latitude-dependent terrain found in the mid-latitudes of Mars and existence of the expansive subsurface ice reservoirs discovered by Odyssey GRS data. Results from the Odyssey GRS instrument indicate ice abundances poleward of 60o (up to 90% by volume) vastly greater than one would expect based upon simple diffusion and the assumed porosity (40%) of the regolith. This disparity led to our initial investigation into subaerial deposition and subsequent sublimation as a means of inserting ice within the regolith. Our most recent work continues this investigation, and permits us to explore the importance of surface adsorption and diffusion of atmospheric vapor as well. Earlier results from the GFDL MGCM have suggested that at high obliquity, ice is not homogeneously distributed across the surface within the latitude band having the coldest annual mean temperatures. Rather, water is preferentially deposited as localized ice ``sheets'' in regions of high thermal inertia and/or high topography. Such findings neglected the thermal inertia feedback of surface ice, which will permit ice to be retained more uniformly within this latitude band. This ice/thermal inertia feedback has been included in our present work. Lastly, we have performed both 1-D and 3-D simulations of the regolith-atmosphere interaction to determine the efficacy of the deposition-sublimation, obliquity-dependent layering mechanism for a full obliquity cycle ( ˜100,000 years). |
| Title: | Surface Properties of Mars' Northern High and Polar Latitudes, Including the Phoenix Landing Site |
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| Authors: | Vasavada, A. R.; Richardson, M. I.; Christensen, P. R. |
| Affiliation: | AA(Department of Earth and Space Sciences, University of California, Los Angeles, CA 90095 ; ashwin@ess.ucla.edu), AB(Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 ; mir@gps.caltech.edu), AC(Department of Geological Sciences, Arizona State University, Tempe, AZ 84287 ; ) |
| Journal: | American Geophysical Union, Fall Meeting 2003, abstract #P21C-06 |
| Publication Date: | Dec 2003 |
| Origin: | AGU |
| Keywords: | 5462 Polar regions, 5464 Remote sensing, 5470 Surface materials and properties, 6225 Mars |
| Abstract Copyright: | (c) 2003: American Geophysical Union |
| Bibliographic Code: | 2003AGUFM.P21C..06V |
| Abstract: | The unprecedented spatial resolution of the Mars Odyssey Thermal Emission Imaging System (THEMIS) is used to infer and compare the optical and thermal infrared properties of martian high-latitude and polar surfaces. Materials of interest include the north polar layered deposits (NPLD), the dark, dune-forming material associated with the north polar cap complex, and the ground ice-rich, latitude-dependent layer (the landing site of the Phoenix Scout mission). To address these goals, we have targeted and acquired THEMIS data as part of the Mars Odyssey Participating Scientist program. We use these THEMIS data in order to understand the morphology and color/thermal properties of the NPLD over relevant (i.e., m to km) spatial scales. We have assembled color mosaics of the data in order to map the distribution of ices, the different layered units, dark material, and underlying basement. The color information from THEMIS is crucial for distiguis-ing these different units, which are less distinct on Mars Orbiter Camera images. In the NPLD, we wish to understand the nature of the marginal scarps and their relationship to the dark material. Co-registered Mars Orbiter Laser Altimeter (MOLA) data provide a measure of scarp morphologies and may help identify the process(es) eroding the NPLD (e.g., mass wast-ing, wind, sublimation). The dark material (or perhaps a darker layered unit in planar configuration) is present at the feet of many scarps, but expresses dune bedforms only tens of kilometers away from the scarps. MOLA will help identify the relationship between the spatial distribution of dark material, the presence of bedforms, and the influence of topography. We have derived the thermophysical properties of the different materials using THEMIS and Mars Global Surveyor Thermal Emission Spectrometer (TES) data, also resulting in a new map of the thermal inertia of Mars' northern hemisphere. Such analyses are complicated by the need for atmospheric correction (of both radiatively active CO2 and dust) and accurate surface temperatures. In order to derive thermal inertias and thermally derived albedos, we employ a 1-D, radiative-convective thermal model of Mars surface, subsurface and atmosphere. The model uses simultaneous (or seasonally relevant) TES atmospheric dust opacities. We also are studying the effects of surface slopes on insolation using MOLA topographic data. |
| Title: | THEMIS High-Resolution Atmospheric Thermal and Visible Imaging Campaign |
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| Authors: | Strausberg, M. J.; Richardson, M. I.; Bandfield, J.; Bender, K. C.; Cherednik, L.; McConnochie, T.; Smith, M. D.; Wang, H.; Bell, J.; Christensen, P. R. |
| Affiliation: | AA(Division of Geological and Planetary Sciences, California Institute of Technology, MC 150-21 1200 E. California Blvd, Pasadena, CA 91125 United States; mel@gps.caltech.edu), AB(Division of Geological and Planetary Sciences, California Institute of Technology, MC 150-21 1200 E. California Blvd, Pasadena, CA 91125 United States; mir@gps.caltech.edu), AC(Department of Geological Sciences, Arizona State University, Tempe, AZ 85257 United States; joshband@imap3.asu.edu), AD(Department of Geological Sciences, Arizona State University, Tempe, AZ 85257 United States; ), AE(Department of Geological Sciences, Arizona State University, Tempe, AZ 85257 United States; ), AF(CRSR, Cornell University, Ithaca, NY 14853 United States; mcconnoc@astro.cornell.edu), AG(Goddard Space Flight Center, NASA, Greenbelt, MD 20771 United States; michael.d.smith.1@gsfc.nasa.gov), AH(Division of Geological and Planetary Sciences, California Institute of Technology, MC 150-21 1200 E! . California Blvd, Pasadena, CA 91125 United States; hqw@gps.caltech.edu), AI(CRSR, Cornell University, Ithaca, NY 14853 United States; jfb8@cornell.edu), AJ(Department of Geological Sciences, Arizona State University, Tempe, AZ 85257 United States; phil.christensen@asu.edu) |
| Journal: | American Geophysical Union, Fall Meeting 2003, abstract #P21C-04 |
| Publication Date: | Dec 2003 |
| Origin: | AGU |
| Keywords: | 5409 Atmospheres: structure and dynamics, 5445 Meteorology (3346), 6225 Mars |
| Abstract Copyright: | (c) 2003: American Geophysical Union |
| Bibliographic Code: | 2003AGUFM.P21C..04S |
| Abstract: | THEMIS offers a unique opportunity to examine mesoscale atmospheric features on Mars in the visible and infrared. The high spatial resolution (˜100 meter per pixel) of the system comes at the cost of imaging spatial coverage, requiring atmospheric features to be targeted. Over the course of the past year, we have been targeting areas and features identified in MOC WA imaging as part of a THEMIS ``atmospheric campaign." These features include topographic cloud systems, polar hood clouds, convective clouds, local dust storms in Hellas and along the retreating edge of the southern seasonal ice cap, and dust fronts in the northern high latitudes. Typically 2-3 band color images and 3-10 band infrared images have been acquired, both with roughly 100 meters per pixel. We will describe the targeting and its rationale, show initial results from the campaign, and provide some interpretation of observed features. |
| Title: | Formation of Obliquity-Driven Subsurface Ice Deposits on Mars: Study With a General Circulation Model |
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| Authors: | Richardson, M. I.; Mischna, M. A.; McCleese, D. J.; Wilson, R. J.; Vasavada, A. R. |
| Affiliation: | AA(California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125 United States; mir@gps.caltech.edu), AB(California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125 United States; University of California, Los Angeles, Department of Earth and Space Sciences 595 Charles Young Drive East, Los Angeles, CA 90025 United States; mischna@ucla.edu), AC(California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125 United States; daniel.j.mccleese@jpl.nasa.gov), AD(Geophysical Fluid Dynamics Laboratory, PO Box 308, Princeton, NJ 08542 United States; rjw@gfdl.noaa.gov), AE(University of California, Los Angeles, Department of Earth and Space Sciences 595 Charles Young Drive East, Los Angeles, CA 90025 United States; ashwin@ess.ucla.edu) |
| Journal: | American Geophysical Union, Fall Meeting 2003, abstract #C12C-01 |
| Publication Date: | Dec 2003 |
| Origin: | AGU |
| Keywords: | 0343 Planetary atmospheres (5405, 5407, 5409, 5704, 5705, 5707), 1655 Water cycles (1836), 3344 Paleoclimatology, 5416 Glaciation, 6225 Mars |
| Abstract Copyright: | (c) 2003: American Geophysical Union |
| Bibliographic Code: | 2003AGUFM.C12C..01R |
| Abstract: | The discovery by Mars Odyssey of large deposits of subsurface ice in regions where surface ice is no longer stable has raised questions about putative past climatic conditions under different orbital states. We have used the GFDL Mars General Circulation Model (MGCM) as a tool for examining these questions, and suggest that these deposits may be quasi-stable permafrost remnants from an earlier period of high obliquity, covered by a sublimation lag deposit formed when the mean annual temperature exceeded the local frost point temperature. We have incorporated a thermal and vapor diffusion code into our GCM to simulate the behavior of water in the regolith and the processes that move water from the atmosphere to the surface and back. Water in the regolith may exist as vapor, ice or adsorbate, in relative abundances dependent upon the soil temperature and ambient pressure. The model results show the effectiveness of ice as a means to reduce the local thermal inertia, thereby reducing annual maximum temperatures and increasing the probability that surface ice deposits of a given thickness will survive throughout the warmer summer, and hence build, essentially, a permafrost layer over obliquity timescales. The development of an ice sheet beneath a sublimation lag appears similar to glacial remnants found in the Antarctic Dry Valleys beneath tens of centimeters of sublimation till. On Earth, these deposits have existed, largely unchanged, for millions of years. On Mars, we suggest that these mid-latitude deposits are several hundred thousand years old, at most-the remnant deposits of the past few martian obliquity cycles. The development of a sublimation lag of a few tens of centimeters seems to be enough to retain ice in these regions until the next high obliquity period. |
| Title: | The Polar Regions and Martian Climate: Studies with a Global Climate Model |
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| Authors: | Wilson, R. J.; Richardson, M. I.; Smith, M. D. |
| Journal: | Third International Conference on Mars Polar Science and Exploration, October 13-17 2003, Alberta, Canada, abstract no.8123 |
| Publication Date: | Oct 2003 |
| Origin: | LPI |
| Bibliographic Code: | 2003mpse.conf.8123W |
| Abstract: | Not Available |
| Title: | Thermophysical Properties of Mars' North Polar Layered Deposits and Related Materials from Mars Odyssey THEMIS |
|---|---|
| Authors: | Vasavada, A. R.; Richardson, M. I.; Byrne, S.; Ivanov, A. B.; Christensen, P. R.; Themis Team |
| Journal: | Third International Conference on Mars Polar Science and Exploration, October 13-17 2003, Alberta, Canada, abstract no.8095 |
| Publication Date: | Oct 2003 |
| Origin: | LPI |
| Bibliographic Code: | 2003mpse.conf.8095V |
| Abstract: | Not Available |
| Title: | Modeling Martian Fog Formation in the Northern High Latitudes During the Retreat of the Seasonal North Polar Cap |
|---|---|
| Authors: | Inada, A.; Richardson, M. I.; Toigo, A. D. |
| Journal: | Third International Conference on Mars Polar Science and Exploration, October 13-17 2003, Alberta, Canada, abstract no.8077 |
| Publication Date: | Oct 2003 |
| Origin: | LPI |
| Bibliographic Code: | 2003mpse.conf.8077I |
| Abstract: | Not Available |
| Title: | Polygonal Landforms at the South Pole and Implications for Exposed Water Ice |
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| Authors: | Piqueux, S.; Byrne, S.; Richardson, M. I. |
| Journal: | Sixth International Conference on Mars, July 20-25 2003, Pasadena, California, abstract no.3275 |
| Publication Date: | Jul 2003 |
| Origin: | LPI |
| Bibliographic Code: | 2003mars.conf.3275P |
| Abstract: | We investigate the connection between exposed water ice, polygonal landforms and surface roughness in the south polar region of Mars. |
| Title: | Temporal Invariance of Wind Orientations as Recorded by Aeolian Features in Proctor Crater |
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| Authors: | Fenton, L. K.; Richardson, M. I.; Toigo, A. D. |
| Journal: | Sixth International Conference on Mars, July 20-25 2003, Pasadena, California, abstract no.3267 |
| Publication Date: | Jul 2003 |
| Origin: | LPI |
| Bibliographic Code: | 2003mars.conf.3267F |
| Abstract: | A mesoscale model is run over Proctor Crater to determine if aeolian features correlate to present-day winds. |
| Title: | Morphological and Thermo-Physical Properties of Slope Streaks |
|---|---|
| Authors: | Aharonson, O.; Schorghofer, N.; Richardson, M. I.; Khatiwala, S. |
| Journal: | Sixth International Conference on Mars, July 20-25 2003, Pasadena, California, abstract no.3255 |
| Publication Date: | Jul 2003 |
| Origin: | LPI |
| Bibliographic Code: | 2003mars.conf.3255A |
| Abstract: | We study morphologic, topographic, and thermal properties of the martian surface at specific sites where slope streaks form using MOC, TES, MOLA, and THEMIS data. |
| Title: | Analysis of Atmospheric Mesoscale Models for Entry, Descent and Landing |
|---|---|
| Authors: | Kass, D. M.; Schofield, J. T.; Michaels, T. I.; Rafkin, S. C. R.; Richardson, M. I.; Toigo, A. D. |
| Journal: | Sixth International Conference on Mars, July 20-25 2003, Pasadena, California, abstract no.3251 |
| Publication Date: | Jul 2003 |
| Origin: | LPI |
| Bibliographic Code: | 2003mars.conf.3251K |
| Abstract: | Each MER lander is sensitive to the martian winds encountered near the surface during the EDL process. Several statistical tools were used to analyze the winds from mesoscale models and asses the saftety of landing sites. Such techniques can also indicate scientifically interesting features. |
| Title: | Analysis of Properties of the North Polar Layered Deposits: THEMIS Data in Context of MGS Data |
|---|---|
| Authors: | Ivanov, A. B.; Byrne, S.; Richardson, M. I.; Vasavada, A. R.; Titus, T. N.; Bell, J. F.; McConnochie, T. H.; Christensen, P. R.; The Themis Science Team |
| Journal: | Sixth International Conference on Mars, July 20-25 2003, Pasadena, California, abstract no.3182 |
| Publication Date: | Jul 2003 |
| Origin: | LPI |
| Bibliographic Code: | 2003mars.conf.3182I |
| Abstract: | We investigate thermal properties of the troughs in the layered deposits using THEMIS IR and TES data. Stratigraphy and composition of the troughs are addressed by THEMIS VIS color images, MOC Narrow Angle images and MOLA DEMs. |
| Title: | THEMIS Observations of Atmospheric Aerosol Optical Depth |
|---|---|
| Authors: | Smith, M. D.; Bandfield, J. L.; Christensen, P. R.; Richardson, M. I. |
| Journal: | Sixth International Conference on Mars, July 20-25 2003, Pasadena, California, abstract no.3168 |
| Publication Date: | Jul 2003 |
| Origin: | LPI |
| Bibliographic Code: | 2003mars.conf.3168S |
| Abstract: | We present results from the retrieval of atmospheric dust and water-ice optical depth from THEMIS infrared images. Data from THEMIS complements the concurrent MGS TES data by offering a later local time and much higher spatial resolution. |
| Title: | Geologic Evolution of Mars' North Polar Layered Deposits and Related Materials from Mars Odyssey THEMIS |
|---|---|
| Authors: | Vasavada, A. R.; Richardson, M. I.; Byrne, S.; Ivanov, A. B.; Christensen, P. R.; The Themis Team |
| Journal: | Sixth International Conference on Mars, July 20-25 2003, Pasadena, California, abstract no.3156 |
| Publication Date: | Jul 2003 |
| Origin: | LPI |
| Bibliographic Code: | 2003mars.conf.3156V |
| Abstract: | We investigate the morphology, color, and thermophysical properties of the north polar layered deposits and related materials with THEMIS data in order to understand their geologic evolution. |
| Title: | Volatile Cycling and Layering on Mars: Observations, Theory and Modeling |
|---|---|
| Authors: | Mischna, M. A.; McCleese, D. J.; Richardson, M. I.; Vasavada, A. R.; Wilson, R. J. |
| Journal: | Sixth International Conference on Mars, July 20-25 2003, Pasadena, California, abstract no.3145 |
| Publication Date: | Jul 2003 |
| Origin: | LPI |
| Bibliographic Code: | 2003mars.conf.3145M |
| Abstract: | Based on theoretical models, spacecraft observations, and new climate modeling of Mars’ orbital cycles, we conclude that surface ice deposits form as subaerial ice sheets, the result of atmospheric saturation and direct surface deposition. |
| Title: | Mars Odyssey THEMIS-VIS: Surface-Atmosphere Separation and Derivation of Aerosol Properties |
|---|---|
| Authors: | McConnochie, T. H.; Bell, J. F., III; Wolff, M. J.; Smith, M. D.; Bandfield, J. L.; Richardson, M. I.; Christensen, P. R. |
| Journal: | Sixth International Conference on Mars, July 20-25 2003, Pasadena, California, abstract no.3077 |
| Publication Date: | Jul 2003 |
| Origin: | LPI |
| Bibliographic Code: | 2003mars.conf.3077M |
| Abstract: | We use multiple-scattering radiative transfer models to correct THEMIS-VIS surface reflectances for the effects of atmospheric aerosols. We also explore the possibility of using these radiative transfer models to derive aerosol properties. |
| Title: | Hydrodynamic Escape from HD209458b: Lessons for VPL (Virtual Planetary Laboratory) |
|---|---|
| Authors: | Parkinson, C. D.; Richardson, M. I.; McConnell, J. C.; Yung, Y. L.; Meadows, V. S. |
| Affiliation: | AA(Caltech/JPL), AB(Caltech), AC(York University), AD(Caltech), AE(Caltech/JPL) |
| Journal: | American Astronomical Society, DPS meeting #35, #18.11; Bulletin of the American Astronomical Society, Vol. 35, p.946 |
| Publication Date: | May 2003 |
| Origin: | AAS |
| Abstract Copyright: | (c) 2003: American Astronomical Society |
| Bibliographic Code: | 2003DPS....35.1811P |
| Abstract: | A new technique has been developed for the treatment of hydrodynamic loss processes from planetary atmospheres utilising the Godunov method. A detailed description of a first order Godunov scheme is given by Godunov (1959), Gombosi (1984), and Leveque (2002). Solving the one-dimensional, steady state approximation becomes problematic at the distance where the outflow becomes supersonic. This method overcomes the instabilities inherent in modeling transonic conditions by solving the coupled, time dependent mass, momentum, and energy equations, instead of integrating time independent equations. We validate a preliminary model of hydrodynamic escape against simple, idealised cases (viz., steady state and isothermal conditions) showing that a robust solution obtains and then compare to existing cases in the literature (Watson et al., 1981; Kasting and Pollack, 1983; Chassefiere, 1996). A focus of this work is on observable aspects of atmospheres that may be useful for comparison between models and observations. "Close-in" hot Jupiter's provide an ideal test case because of recent observations of HD 209458b. The general tools developed here will be applied to various problems such as the early Earth and Venus, and close-in extrasolar gas giant planets and are directly applicable to modifications required for the VPL terrestrial planet models. |
| Title: | Astronomical Detection of Biosignatures from Extrasolar Planets: Virtual Planetary Laboratory (VPL) Architecture and Model Validation |
|---|---|
| Authors: | Parkinson, C. D.; Liu, J.; Meadows, V. S.; Allen, M.; Crisp, D.; Richardson, M. I.; Yung, Y. L. |
| Journal: | EGS - AGU - EUG Joint Assembly, Abstracts from the meeting held in Nice, France, 6 - 11 April 2003, abstract #8136 |
| Publication Date: | Apr 2003 |
| Origin: | EGU |
| Bibliographic Code: | 2003EAEJA.....8136P |
| Abstract: | In order to recognize signatures of life on extrasolar planets, a suite of computer models called the VPL is being developed that will allow the simulation of a broad range of planetary environments both with and without life, and determination of the spectral signature of these environments. These tools represent a significant innovation for the understanding of extrasolar planetary atmospheres and astronomical biosignatures. We present the overall VPL architecture and a validation of the chemistry/climate/radiative transfer part of the model. To validate the model, we use simulations using a present day Martian model atmosphere in conjunction with a Mie scattering dust column over surface H2O ice. In this way, we attempt to understand the degree to which greenhouse effects produced by the dust particles in the Martian atmosphere can allow for temperatures warm enough to permit the formation of liquid surface water, which is required for the presence of life. Perturbing the parameters of the model will show if there is an optimal amount of dust that can produce a greenhouse effect for periods long enough to facilitate the presence of life on Mars. |
| Title: | Martian Polar Wind Patterns Derived from Mapping of Seasonal Cap Dark Streaks |
|---|---|
| Authors: | Diniega, S.; Richardson, M. I.; Ewald, S. P.; Toigo, A. D.; Byrne, S. |
| Journal: | 34th Annual Lunar and Planetary Science Conference, March 17-21, 2003, League City, Texas, abstract no.2125 |
| Publication Date: | Mar 2003 |
| Origin: | LPI |
| Bibliographic Code: | 2003LPI....34.2125D |
| Abstract: | Frost streaks identified in images taken by MOC/MGS were used to develop a map of the martian south pole's southern spring circulation patterns. The same region and season was then examined with a mesoscale atmospheric circulation modeling program. |
| Title: | Early Results from the Odyssey THEMIS Investigation |
|---|---|
| Authors: | Christensen, P. R.; Bandfield, J. L.; Bell, J. F., III; Hamilton, V. E.; Ivanov, A.; Jakosky, B. M.; Kieffer, H. H.; Lane, M. D.; Malin, M. C.; McConnochie, T.; McEwen, A. S.; McSween, H. Y., Jr.; Moersch, J. E.; Nealson, K. H.; Rice, J. W., Jr.; Richardson, M. I.; Ruff, S. W.; Smith, M. D.; Titus, T. N. |
| Journal: | 34th Annual Lunar and Planetary Science Conference, March 17-21, 2003, League City, Texas, abstract no.1519 |
| Publication Date: | Mar 2003 |
| Origin: | LPI |
| Bibliographic Code: | 2003LPI....34.1519C |
| Abstract: | The Mars Odyssey THEMIS thermal infrared and visible/near-IR multi-spectral images have been used to study geologic units and layers, the distribution of rocks, bedrock, sand, and dust, 100-m scale compositional variations, polar processes, and visible color and morphology. |
| Title: | Obliquity, Ice Sheets, and Layered Sediments on Mars: What Spacecraft Observations and Climate Models are Telling Us |
|---|---|
| Authors: | Richardson, M. I.; McCleese, D. J.; Mischna, M.; Vasavada, A. R. |
| Journal: | 34th Annual Lunar and Planetary Science Conference, March 17-21, 2003, League City, Texas, abstract no.1281 |
| Publication Date: | Mar 2003 |
| Origin: | LPI |
| Bibliographic Code: | 2003LPI....34.1281R |
| Abstract: | Mars Odyssey GRS data, along with images of recent ground ice and new climate modeling, suggest that the subaerial formation and subsequent slow devolitization of ice sheets may be an important, ongoing process globally, over climate timescales. |
2002
| Title: | Seasonally-Active Water on Mars: Vapour, Ice, Adsorbate, and the Possibility of Liquid |
|---|---|
| Authors: | Richardson, M. I. |
| Affiliation: | AA(Division of Geological and Planetary Sciences, California Institute of Technology, MC 150-21, 1200 E. California Blvd., Pasadena, CA 91125 United States ; mir@gps.caltech.edu) |
| Journal: | American Geophysical Union, Fall Meeting 2002, abstract #P72C-06 |
| Publication Date: | Dec 2002 |
| Origin: | AGU |
| Keywords: | 1655 Water cycles (1836), 3346 Planetary meteorology (5445, 5739), 5416 Glaciation, 5462 Polar regions, 6225 Mars |
| Abstract Copyright: | (c) 2002: American Geophysical Union |
| Bibliographic Code: | 2002AGUFM.P72C..06R |
| Abstract: | Seasonally-active water can be defined to include any water reservoir that communicates with other reservoirs on time scales of a year or shorter. It is the interaction of these water reservoirs, under the influence of varying solar radiation and in conjunction with surface and atmospheric temperatures, that determines the phase-stability field for water at the surface, and the distribution of water in various forms below, on, and above the surface. The atmosphere is the critical, dynamical link in this cycling system, and also (fortunately) one of the easiest to observe. Viking and Mars Global Surveyor observations paint a strongly asymmetric picture of the global seasonal water cycle, tied proximately to planetary eccentricity, and the existence of residual ice caps of different composition at the two poles. The northern summer experiences the largest water vapour columns, and is associated with sublimation from the northern residual water ice cap. The southern summer residual carbon dioxide ice cap is cold trap for water. Asymmetry in the water cycle is an unsolved problem. Possible solutions may involve the current timing of perihelion (the water cap resides at the pole experiencing the longer but cooler summer), the trapping of water ice in the northern hemisphere by tropical water ice clouds, and the bias in the annual-average, zonal-mean atmospheric circulation resulting from the zonal-mean difference in the elevation of the northern and southern hemispheres. Adsorbed and frozen water have proven harder to constrain. Recent Odyssey Gamma Ray Spectrometer results suggest substantial ground ice in the mid- and high-latitudes, but this water is likely below the seasonal skin depth for two reasons: the GRS results are best fit with such a model, and GCM models of the water cycle produce dramatically unrealistic atmospheric vapour distributions when such a very near surface, GRS-like distribution is initialized - ultimately removing the water to the northern and southern caps. Similar climate-models of the water cycle also do not need much exchangeable adsorbed water in order to explain the observed vapour distributions. The possibility of liquid water is tantalizing, but difficult to definitively judge. On scales greater than a meter or so, Mars is most definitely well away from the water triple point--although the surface pressure can exceed 6.1 mbars, the partial pressure of water vapor (to which the triple point refers) is at best orders of magnitude lower. Several careful studies have shown, however, that locally transient (meta-stable) liquid is possible, if the net heating of ice deposits is high enough. This process is aided if the total surface pressure exceeds 6.1mbar (this prevents boiling, or the explosive loss of vapour into the atmosphere) or if the liquid is covered by a thin ice shell, and is only possible if surface temperatures exceed 273K (for pure water, or the appropriate eutectic for brines) and if ice is present. The former challenge is much easier to meet than the latter. The melt scenario requires that ice deposited in winter must be protected from sublimation as surface temperatures increase in spring, but then exposed to the peak of solar heating in summer. Available spacecraft observations of seasonal water will be discussed with the aid of GCM model simulations, and examined in the context of water distributions and phases. |
| Title: | Orbitally-Induced, Quasi-Periodic Climate Change on Mars: Modelling Changes in the Global Cycling of Water and Carbon Dioxide |
|---|---|
| Authors: | Mischna, M. A.; Richardson, M. I.; Wilson, R. J. |
| Affiliation: | AA(UCLA, 595 Charles E. Young Drive East, Los Angeles, CA 90095 United States ; mischna@ucla.edu), AB(California Institute of Technology, MC 150-21 1200 E. California Blvd., Pasadena, CA 91125 United States ; mir@gps.caltech.edu), AC(Geophysical Fluid Dynamics Laboratory, National Oceanic and Atmospheric Administration PO Box 308, Princeton, NJ 08542 United States ; rjw@gfdl.noaa.gov) |
| Journal: | American Geophysical Union, Fall Meeting 2002, abstract #P52A-0367 |
| Publication Date: | Dec 2002 |
| Origin: | AGU |
| Keywords: | 0343 Planetary atmospheres (5405, 5407, 5409, 5704, 5705, 5707), 1620 Climate dynamics (3309), 3344 Paleoclimatology, 5445 Meteorology (3346), 6225 Mars |
| Abstract Copyright: | (c) 2002: American Geophysical Union |
| Bibliographic Code: | 2002AGUFM.P52A0367M |
| Abstract: | Mars' orbital parameters (obliquity, eccentricity and argument of perihelion) are thought to have varied substantially on time scales >105 years. Such variations, especially in obliquity, may drastically affect the circulation of the atmosphere and volatile cycling. In this study, we focus on the response of the water and carbon dioxide cycles to changes in these orbital parameters, chiefly obliquity. The study employs the Geophysical Fluid Dynamics Laboratory Mars General Circulation Model, conducting simulations over a range of orbital states to examine changes in the cycling and deposition of these volatiles. This model contains full 3D accounting of atmospheric water and carbon dioxide as well as a basic dust cycle. The present martian obliquity is 25°, though it is believed to have recently varied between 15 and 45 degrees. Our simulations look at present martian conditions, only with obliquity varying between 5 and 60 degrees. Simulations are run out until water and carbon dioxide budgets have reached equilibrium--typically 30-40 years. As expected, volatile cycling on Mars increases with obliquity, as the polar caps are exposed to increased insolation, leading to greater seasonal ice caps and ultimately development of surface water ice in the now thermally favorible low latitudes. By 45°, water ice is stable in a broad band just north of the equator. Such an ice distribution has potential implications for the surface wind pattern through the ice-albedo effect on surface heating. Permanent polar CO2 caps are not stable under present conditions, but we find CO2 cap growth and corresponding atmospheric deflation to be evident at very low obliquities. We find that for most choices of orbital conditions, the northern hemisphere remains the stable pole for water ice, a result of the martian topographic dichotomy. We have begun to look at the impact of desorbed CO2 and H2O ice from the regolith on climatic conditions. Present estimates of the volatile abundance in the regolith vary greatly, but recent Mars Odyssey results hint at large abundances of water ice in the martian high-latitude regolith. The results of this study should better define models of polar volatile evolution, specifically those of layered terrain formation. The radiative feedback effects of increased atmospheric CO2 and H2O from the polar caps and regoliths has yet to be examined. Future plans include more accurate representations of dust injection and radiative transfer to tackle this problem. |
| Title: | The Response of the Martian Circulation to Orbital Parameter Variations |
|---|---|
| Authors: | Liu, J.; Richardson, M. I.; Wilson, R. J. |
| Affiliation: | AA(Division of Geological and Planetary Sciences, California Institute of Technology, MC 150-21 1200 E. California Blvd., Pasadena, CA 91125 United States ; ljj@gps.caltech.edu), AB(Division of Geological and Planetary Sciences, California Institute of Technology, MC 150-21 1200 E. California Blvd., Pasadena, CA 91125 United States ; mir@gps.caltech.edu), AC(NOAA/Geophysical Fluid Dynamics Laboratory, P.O. Box 308, Princeton, NJ 08542 United States ; rjw@gfdl.noaa.gov) |
| Journal: | American Geophysical Union, Fall Meeting 2002, abstract #P52A-0366 |
| Publication Date: | Dec 2002 |
| Origin: | AGU |
| Keywords: | 0343 Planetary atmospheres (5405, 5407, 5409, 5704, 5705, 5707), 3319 General circulation, 3344 Paleoclimatology, 5445 Meteorology (3346), 6225 Mars |
| Abstract Copyright: | (c) 2002: American Geophysical Union |
| Bibliographic Code: | 2002AGUFM.P52A0366L |
| Abstract: | The circulation of the Martian atmosphere may be substantially affected by changes in orbital parameters. Such changes will undoubtedly alter the seasonal distribution of incident solar radiation on time scales greater than 105 years, and hence the forcing of the atmospheric circulation. For this investigation, we focus on the response of the general circulation to changes in obliquity, eccentricity, and argument of perihelion. We use the Geophysical Fluid Dynamics Laboratory (GFDL) Mars General Circulation Model (GCM) to examine changes in the nature of the Hadley circulation, polar jets, and eddies as orbital elements are varied. A number of basic findings emerge from the simulations. For example, the Hadley cell exhibits strongly non-continuous variation with obliquity. As obliquity is increased from 0o, the northern summer circulation retains an equinoctial-like dual cell pattern until obliquity exceeds 10o. Only after that does the dominant cross-equatorial cell pattern emerge. Conversely, the southern hemisphere summer cell develops a strong cross-equatorial pattern at obliquities below 5o. This starkly asymmetric Hadley cell behaviour results from the global mean topographic slope. The simulations also highlight other ways in which topography places a control on the extent and strength of the Martian Hadley circulations. The polar jet is also affected by changes in obliquity. For obliquities above 45o, we find that the expanded and strengthened descending branch of the Hadley cell adiabatically warms the polar regions, reducing the latitudinal temperature gradient and decreasing the strength of the corresponding polar jet. |
| Title: | Simulation of the Martian Boundary Layer and Dust Devils With the Mars MM5 Mesoscale Atmospheric Model |
|---|---|
| Authors: | Toigo, A.; Richardson, M. I.; Gierasch, P. J.; Ewald, S. P.; Wilson, R. |
| Affiliation: | AA(Cornell University, Center for Radiophysics and Space Research, Ithaca, NY 14853 United States ; toigo@astro.cornell.edu), AB(California Institute of Technology, Division of Geological and Planetary Sciences 1200 E. California Boulevard, Pasadena, CA 91125 United States ; mir@gps.caltech.edu), AC(Cornell University, Center for Radiophysics and Space Research, Ithaca, NY 14853 United States ; gierasch@astro.cornell.edu), AD(California Institute of Technology, Division of Geological and Planetary Sciences 1200 E. California Boulevard, Pasadena, CA 91125 United States ; spe@gps.caltech.edu), AE(NOAA/GFDL, P. O. Box 308, Princeton, NJ 08542 United States ; rjw@GFDL.noaa.gov) |
| Journal: | American Geophysical Union, Fall Meeting 2002, abstract #P51A-0333 |
| Publication Date: | Dec 2002 |
| Origin: | AGU |
| Keywords: | 0305 Aerosols and particles (0345, 4801), 3329 Mesoscale meteorology, 3337 Numerical modeling and data assimilation, 5445 Meteorology (3346), 6225 Mars |
| Abstract Copyright: | (c) 2002: American Geophysical Union |
| Bibliographic Code: | 2002AGUFM.P51A0333T |
| Abstract: | The observed year-to-year repeatability of Martian atmospheric temperatures and dust opacities in northern spring and summer suggests that the seasonal cycle of Martian atmospheric dustiness cannot be explained uniquely in terms of large (regional and global scale) dust storms. Instead, a steady source of atmospheric dust is needed that generates a seasonal supply pattern that is essentially repeatable. Dust devils have been widely suggested to operate in this role. Theoretical studies to date have mainly focused on analytical models of dust devils as thermodynamic and dynamic systems. In this presentation, we discuss three-dimensional, numerical simulations of the Martian convective boundary layer, and specifically convective vortex/dust devil development. The simulations are undertaken with the Mars MM5 mesoscale atmospheric model developed at Caltech and Cornell University. The model is nonhydrostatic, and employs parameterizations for heat diffusion in the Martian subsurface, radiative heating due to dust and carbon dioxide gas in the visible and thermal infrared, radiatively and dynamically interactive dust, and (where applicable) the cycling of carbon dioxide and water between the surface and atmosphere. In these simulations of the Martian boundary layer, the model is used with a horizontal grid spacing of 20 to 100 m, and with a minimum of 100 points in each direction, and over 50 levels in the vertical direction. We initially simulate a region near the equator, with surface properties characteristic of the Sinus Meridiani ("Hematite") region and for mid southern summer. We also show simulations for a location in the northern tropics and with surface properties consistent with the Amazonis Planitia region. These simulations are conducted near southern spring equinox, a time when Mars Orbiter Camera (MOC) images suggest development of copious, massive dust devil structures. In all cases, we find evidence for the development of convective, vertically aligned vortices. We will discuss the nature and behavior of the various vortices developed in the simulations. |
| Title: | A Survey of Martian Dust Devil Activity Using Mars Global Surveyor Mars Orbiter Camera Images |
|---|---|
| Authors: | Fisher, J.; Richardson, M. I.; Ewald, S. P.; Toigo, A. D.; Wilson, R. J. |
| Affiliation: | AA(Division of Geological and Planetary Sciences, California Institute of Technology, MC 150-21, 1200 E. California Blvd., Pasadena, CA 91125 United States ; jennyf@caltech.edu), AB(Division of Geological and Planetary Sciences, California Institute of Technology, MC 150-21, 1200 E. California Blvd., Pasadena, CA 91125 United States ; mir@gps.caltech.edu), AC(Division of Geological and Planetary Sciences, California Institute of Technology, MC 150-21, 1200 E. California Blvd., Pasadena, CA 91125 United States ; spe@gps.caltech.edu), AD(Center for Radio Physics and Space Research, Cornell University, CRPR, Ithaca, NY 14853 United States ; toigo@astro.cornell.edu), AE(NOAA/Geophysical Fluid Dynamics Laboratory, P.O. Box 308, Princeton, NJ 08542 United States ; rjw@gfdl.noaa.gov) |
| Journal: | American Geophysical Union, Fall Meeting 2002, abstract #P51A-0332 |
| Publication Date: | Dec 2002 |
| Origin: | AGU |
| Keywords: | 0343 Planetary atmospheres (5405, 5407, 5409, 5704, 5705, 5707), 3307 Boundary layer processes, 3314 Convective processes, 5445 Meteorology (3346), 6225 Mars |
| Abstract Copyright: | (c) 2002: American Geophysical Union |
| Bibliographic Code: | 2002AGUFM.P51A0332F |
| Abstract: | We present results from an orbital survey of Martian dust devils using the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) wide- and narrow-angle (WA and NA) images. The survey includes all available imaging data (mapping and pre-mapping orbit), through to mission phase E06. Due to the large volume of data, we have concentrated on surveying limited regions, selected variously on the basis of where dust devils or other dust storm activity has previously been reported, on the basis of where lander observations have been or will be obtained, and on the basis of predictions from numerical atmospheric models. Our study regions to date include: Amazonis Planitia (25-45N, 145-165W), Sinus Meridiani (10S-10N, 10E-10W), Chryse Planitia (10-30N, 30-60W), Solis Planum (15-45S, 75-105W), Hellas Planitia (15-60S, 265-315W), Casius (45-65N, 255-285W), Utopia Planitia (25-45N, 225-255W), Sinai Planum (10-20S, 60-100W), Mare Cimmerium (10-45S, 180-220W). We have compiled statistics on dust devil activity in three categories: dust devils observed in NA images, dust devils observed in WA images, and dust devil tracks observed in NA images. For each region and each category, we have compiled statistics for four seasonal date bins, centered on the equinoxes and solstices: Ls=45-135 (northern summer solstice), Ls=135-225 (northern autumn equinox), Ls=225-315 (northern winter solstice), and Ls=315-45 (northern spring equinox). Our survey has highlighted great spatial variability in dust devil activity, with the Amazonis Planitia region being by far the dominant location for activity. This region is additionally characterized by a large size range of dust devils, including individual devils up to several km in height. Other regions in which dust devils have been frequently imaged include Utopia, Solis, and Sinai. Numerous dust devil tracks were observed in Casius and Cimmerium, but with very few accompanying dust devils. This suggests dust devils occurring in local times other than that of the MGS orbit (~2pm). Our seasonal statistics suggest a very strong preference for Amazonis and Solis dust devil activity to occur in the northern autumn season. Conversely, Utopia shows dust devil activity which is relatively constant, except in the northern spring period. The observations will be presented, and compared with numerical model predictions. Initial results from this survey have already been used to define target regions for very high resolution simulations of dust devil development using the Caltech/Cornell Mars MM5 model. |
| Title: | The Dependence of Atmospheric Circulation and Heat Transport on the Planetary Rotation Rate |
|---|---|
| Authors: | Basu, S.; Richardson, M. I.; Wilson, R. J. |
| Affiliation: | AA(Caltech, MC 150-21 1200 E. California blvd., Pasadena, CA 91125 ; shabari@gps.caltech.edu), AB(Caltech, MC 150-21 1200 E. California blvd., Pasadena, CA 91125 ; mir@gps.caltech.edu), AC(Geophysical Fluid Dynamics Laboratory, P. O. Box 308, Princeton, NJ 08542 ; rjw@GFDL.noaa.gov) |
| Journal: | American Geophysical Union, Fall Meeting 2002, abstract #P22C-0411 |
| Publication Date: | Dec 2002 |
| Origin: | AGU |
| Keywords: | 0343 Planetary atmospheres (5405, 5407, 5409, 5704, 5705, 5707) |
| Abstract Copyright: | (c) 2002: American Geophysical Union |
| Bibliographic Code: | 2002AGUFM.P22C0411B |
| Abstract: | Simplified models of planetary climate require a parameterization for the equator-to-pole transport of heat and its dependence on factors, including the planetary rotation rate. Various such parameterizations exist, including ones based on the theory of baroclinic eddy mixing, and on principles of global entropy generation. However, such parameterizations are difficult to test given the limited available observational opportunities. In this study, we use a numerical model to examine heat flux dependencies, as part of a wider study of circulation regime sensitivity to rotation rates and other parameters. This study makes use of a simplified version of the Geophysical Fluid Dynamics Laboratory (GFDL) "Skyhi" General Circulation Model (GCM). All terrestrial hydrological processes have been stripped from the model, which in the form used here, is adapted from the Martian version of Skyhi. The atmosphere has the gas properties of CO2, except that it has been made uncondensible. No aerosols or surface ices are allowed. The model surface is flat, and of uniform albedo and thermal inertia. For the simulations presented in this study, the diurnal, seasonal, and eccentricity cycles have been disabled ({ i.e.} the surface and atmosphere receives constant, daily- and seasonally-averaged incident solar radiation). Radiative heating is treated with a band model for CO2 gas in the thermal and near-infrared bands. The use of a complex model to examine simplified theory of heat transport requires some justification since it is not necessarily clear that these models (GCM's) provide an accurate emulation of the real atmosphere (of any given planet). In this study, we have intentionally removed those aspects of GCM's that are of greatest concern. Especially for terrestrial GCM's, the hydrologic cycle is a major source of uncertainty due to radiative feedbacks, and cloud coupling to small-scale, convective mixing. For other planets, aerosols are important as radiatively and dynamical active species. Yet an additional cause of error, especially when testing global entropy principles, is the condensation of the atmosphere (as in the case of Mars). We have eliminated all of these concerns in the pure, non-condensible gas atmosphere of our simplified model. Our results will be compared with those of simplified theoretical predictions, and differences discussed. |
| Title: | Meteorology of Candidate Mars Exploration Rover Landing Sites as Predicted by a Mesoscale Model |
|---|---|
| Authors: | Richardson, M. I.; Toigo, A. D. |
| Affiliation: | AA(Division of Geological and Planetary Sciences, California Institute of Technology, MC 150-21, 1200 E. California Blvd., Pasadena, CA 91125 United States ; mir@gps.caltech.edu), AB(Center for Radiophysics and Space Research, Cornell University, CRSP, Ithaca, NY 14853 United States ; toigo@astro.cornell.edu) |
| Journal: | American Geophysical Union, Fall Meeting 2002, abstract #P21C-08 |
| Publication Date: | Dec 2002 |
| Origin: | AGU |
| Keywords: | 0305 Aerosols and particles (0345, 4801), 3329 Mesoscale meteorology, 3337 Numerical modeling and data assimilation, 5445 Meteorology (3346), 6225 Mars |
| Abstract Copyright: | (c) 2002: American Geophysical Union |
| Bibliographic Code: | 2002AGUFM.P21C..08R |
| Abstract: | The meteorology of the Mars Exploration Rover (MER) candidate landing sites is of importance because of the constraint it provides on the likely ability of the rovers to successfully land and operate. The meteorology may also be of interest insofar as the landscapes to be traversed and studied by the rovers may be influenced to a greater or lesser degree by aeolian activity. In support of the MER Program, we have conducted studies of several of the candidate landing sites using the Mars Mesoscale Model developed at Caltech and Cornell University as an adaptation of the terrestrial PSU/NCAR Mesoscale Model (MM5). The sites studied include Meridiani (``Hematite"), Gusev, and Mellas. The model results suggest that winds associated with convection and/or topography may be of concern at each of the landing sites. The relatively flat Hematite site is simulated to develop strong, deep convection. At highest resolution (few hundred meters), the convection is predicted to be cellular with significant up- and down-drafts. The local time of landing for both MER rovers is during the period of most active convection at all sites. Gusev and Mellas show varying degrees of topographic influence on winds. At Gusev, the crater walls provide strong foci for upslope-downslope circulations, while the walls and other nearby topography provide ``anchor" points for the initiation (initial upwelling) of convection during the day. Mellas provides a case example of strongly channelized flow. Convection is less of a concern at Mellas, but is replaced by diurnally reversing up-canyon and down-canyon flow. The flow patterns are also strongly influenced by the effects of canyon wall heating by solar radiation. In summary, the thin Martian atmosphere responds strongly to slope heating by developing slope winds which provide a challenge to missions seeking to closely approach ``interesting" terrain. Equally a problem for the MER mission, for flat landing sites, is the use of an early afternoon local time of landing, coinciding with the peak of boundary layer convection. |
| Title: | Morphologic, Topographic, and Thermal Analysis of Slope Streaks on Mars |
|---|---|
| Authors: | Aharonson, O.; Schorghofer, N.; Khatiwala, S.; Richardson, M. I. |
| Affiliation: | AA(Division of Geological and Planetary Sciences, California Institute of Technology, MC 150-21, Pasadena, CA 91125 United States ; oa@caltech.edu), AB(Division of Geological and Planetary Sciences, California Institute of Technology, MC 150-21, Pasadena, CA 91125 United States ; norbert@gps.caltech.edu), AC(Lamont Doherty Earth Observatory, Columbia University, Oceanography 201, Palisades, NY 10964 United States ; spk@ldeo.columbia.edu), AD(Division of Geological and Planetary Sciences, California Institute of Technology, MC 150-21, Pasadena, CA 91125 United States ; mir@gps.caltech.edu) |
| Journal: | American Geophysical Union, Fall Meeting 2002, abstract #P12A-0364 |
| Publication Date: | Dec 2002 |
| Origin: | AGU |
| Keywords: | 5464 Remote sensing, 6225 Mars |
| Abstract Copyright: | (c) 2002: American Geophysical Union |
| Bibliographic Code: | 2002AGUFM.P12A0364A |
| Abstract: | Surfaces containing features known as slope streaks are common on Mars in regions where thermal-inertia is low and steep slopes are frequent. We have recently compiled a catalog of slope streak images and identified previously unrecognized correlations with surface properties. Building on this work, we analyze data from Mars Orbiter Camera, from Mars Orbiter Laser Altimeter, and from the Thermal Emission Imaging System instrument on board Mars Odyssey, to constrain the physical properties and thermal conditions at the specific sites where slope streaks are forming. A number of proposed theories explaining the formation mechanism of slope streaks can be tested using new data, including an exciting possibility of the potential role of a water phase-transition. |
| Title: | Initial Atmospheric Observation Results From Mars Odyssey THEMIS |
|---|---|
| Authors: | Smith, M. D.; Bandfield, J. L.; Richardson, M. I.; Christensen, P. R. |
| Affiliation: | AA(NASA Goddard Space Flight Center, Code 693.0, Greenbelt, MD 20771 United States ; Michael.D.Smith.1@gsfc.nasa.gov), AB(Arizona State University, Mars Space Flight Facility, Tempe, AZ 85287-6305 United States ; joshband@asu.edu), AC(California Institute of Technology, Department of Geological and Planetary Sciences, Pasadena, CA 91125 United States ; mir@gps.caltech.edu), AD(Arizona State University, Mars Space Flight Facility, Tempe, AZ 85287-6305 United States ; Phil.Christensen@asu.edu) |
| Journal: | American Geophysical Union, Fall Meeting 2002, abstract #P11B-12 |
| Publication Date: | Dec 2002 |
| Origin: | AGU |
| Keywords: | 0305 Aerosols and particles (0345, 4801), 0394 Instruments and techniques, 5409 Atmospheres: structure and dynamics, 5445 Meteorology (3346), 5464 Remote sensing |
| Abstract Copyright: | (c) 2002: American Geophysical Union |
| Bibliographic Code: | 2002AGUFM.P11B..12S |
| Abstract: | The Thermal Emission Imaging System (THEMIS) is continuing the infrared global monitoring of Martian dust and water ice aerosols as well as atmospheric temperatures started by the Mariner 9 Infrared Interferometric Spectrometer (IRIS), Viking Infrared Thermal Mapper (IRTM), and the Mars Global Surveyor (MGS) Thermal Emission Spectrometer (TES) instruments. Aerosol optical depth is retrieved in a manner similar to retrieval algorithms used with TES data. THEMIS 9 point spectra are converted to the equivalent column integrated optical depth. The relative contributions of dust and water ice to the observed optical depth are then determined using a least squares fit of predetermined water ice and dust opacity spectral shapes to the measured THEMIS optical depth. Several refinements have been made to the aerosol opacity retrieval algorithms for increased accuracy of both aerosol abundances as well as surface temperatures. The opacity retrieval algorithm iteratively solves for a self-consistent solution for surface temperature as well as aerosol abundance. As a result, no atmospheric transparency wavelength needs to be assumed. Surface emissivity maps are also now incorporated into the retrieval algorithm. Results to date are consistent with concurrent TES observations, displaying low dust opacities and the onset of the perihelion water ice cloud belt as Mars progresses towards northern summer. The Mars Odyssey mission plan includes observations that drift from local times of approximately 3-6 PM. These local times combined with concurrent TES observations of a local time of 2 PM will allow for some resolution of diurnal atmospheric variations, such as water ice cloud abundances. The THEMIS investigation will extend the continuous infrared monitoring of the Martian atmosphere, bridging the MGS TES and the 2005 Mars Reconnaissance Orbiter (MRO) Mars Climate Sounder (MCS) investigations. This continuous long-term monitoring is essential for the understanding of the atmospheric processes and cycles present in the Martian atmosphere. |
| Title: | Cyclones, tides and the origin of major dust storms on Mars |
|---|---|
| Authors: | Wang, H.; Richardson, M. I.; Ingersoll, A. P.; Wilson, R. J.; Zurek, R. W. |
| Affiliation: | AA(Caltech), AB(Caltech), AC(Caltech), AD(GFDL), AE(JPL) |
| Journal: | American Astronomical Society, DPS Meeting #34, #06.02; Bulletin of the American Astronomical Society, Vol. 34, p.844 |
| Publication Date: | Sep 2002 |
| Origin: | AAS |
| Abstract Copyright: | (c) 2002: American Astronomical Society |
| Bibliographic Code: | 2002DPS....34.0602W |
| Abstract: | The Martian dust storm provides one of the most spectacular examples of transient meteorological phenomena in the solar system. While most Martian dust lifting events are local in scale, tens to hundreds of kilometers, some are regional storms thousands of kilometers in size, and a few have been observed to initiate global dust storms that shroud the entire planet. Large dust storms represent the most dramatic component of the Martian dust cycle - one of the three main cycles determining the climate on Mars. They can generate significant perturbations of the global climate, increasing mid-level air temperatures by tens of degrees Kelvin. These storms can be categorized as major storms. Observations before Mars Global Surveyor (MGS) indicate that classical major dust storms originate in the southern hemisphere during the "dust storm season" of southern spring and summer (Ls=180-360). It was suspected that the dynamics of major dust storms involve feedback between the atmospheric circulation and radiative heating of lofted dust. However, there has been little success in providing mechanisms to explain the origin and/or transience of major storms. Recently, a new category of major dust storm has been identified, with dust lifting initially associated with northern-hemisphere fronts, and involving flushing of dust from the northern to southern hemisphere. Such "flushing" dust storms are mainly observed in mid northern fall and mid northern winter. We present a mechanism for the development of these storms, including natural explanations for diurnal, seasonal, and interannual variability of the storms. Dust flushing from the northern hemisphere requires coherence and cooperation between three major dynamical systems: baroclinic storms, thermal tides, and the Hadley circulation. Once dust is flushed into the southern hemisphere, accumulation of dust in the Hadley convergence zone will greatly increase the strength of the circulation, leading to major dust storm. These results provide not only a coherent picture of major storm development and transience, but also an example of cooperative interaction of Mars' major dynamical systems over planetary length-scales. |
| Title: | An assessment of the global, seasonal, and interannual spacecraft record of martian climate in the thermal infrared |
|---|---|
| Authors: | Liu, J.; Richardson, M. I.; Wilson, R. J. |
| Affiliation: | AA(California Institute of Technology), AB(California Institute of Technology), AC(Geophysical Fluid Dynamics Lab., NOAA) |
| Journal: | American Astronomical Society, DPS Meeting #34, #05.02; Bulletin of the American Astronomical Society, Vol. 34, p.841 |
| Publication Date: | Sep 2002 |
| Origin: | AAS |
| Abstract Copyright: | (c) 2002: American Astronomical Society |
| Bibliographic Code: | 2002DPS....34.0502L |
| Abstract: | Comprehensive inter-comparison of thermal infrared data collected by Mariner 9, Viking, and Mars Global Surveyor (MGS) is presented, with a specific focus on air temperatures, dust opacities, and water ice opacities. Emphasis is placed upon creating a uniform data set so as to most effectively reduce inter-instrument biases and offsets. We show that the globally-averaged martian atmosphere executes an exceedingly repeatable annual cycle of air temperature, closing in northern spring and summer to within a Kelvin. The annual cycle shows a strong asymmetry about the equinoxes, with northern summer showing relatively low temperatures and essentially no short-term (tens of days) variability. Viking and MGS air temperatures are essentially indistinguishable, suggesting that the Viking and MGS eras are characterized by exactly the same climatic state. Southern summer is characterized by strong dust storm activity, and we note that the period around Ls=225 is characterized by very high dust opacities associated with dust storm development or decay in every year thus far observed by spacecraft. Dust opacity shows a highly repeatable annual cycle, closing to essentially the same values each year in northern spring and summer, with Viking and MGS opacities being very similar. We show that both Viking and MGS data sets show significant (and similar) polar cap edge dust storm activity. The origins of the various major dust storms can be identified in the thermal infrared data from Viking and MGS, including the "flushing" of dust from the northern autumn baroclinic zone into the southern hemisphere tropics, which has also been identified in visible imaging. Water ice opacities have been retrieved from Viking infrared data for the first time. We show that the cloud belt structure and evolution is essentially the same in each of the multiple years observed by Viking and MGS. Relatively subtle spatial features recur in the cloud belt from year-to-year, suggesting the influence of surface topography and thermophysical properties, and consistent supply of water vapor. The seasonal evolution of the tropical cloud belt through northern spring and summer is shown, with the only significant deviations between years occurring from Ls=140-160, where opacities fall in the second MGS year associated with a small dust storm. Polar hood clouds are observed in the Viking and MGS observations with similar timing and extent. It would seem that the martian atmosphere executes a very repeatable annual cycle of atmospheric phenomena, with the only significant exception being the occurrence of major dust events. After such dust events, the atmosphere rapidly relaxes to its stable, repeatable state. |
| Title: | Recent Atmospheric Observations of Mars by THEMIS and TES |
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| Authors: | Smith, M. D.; Bandfield, J. L.; Richardson, M. I.; Christensen, P. R. |
| Affiliation: | AA(NASA/GSFC), AB(Ariz. St.), AC(Caltech), AD(Ariz. St.) |
| Journal: | American Astronomical Society, DPS Meeting #34, #05.01; Bulletin of the American Astronomical Society, Vol. 34, p.841 |
| Publication Date: | Sep 2002 |
| Origin: | AAS |
| Abstract Copyright: | (c) 2002: American Astronomical Society |
| Bibliographic Code: | 2002DPS....34.0501S |
| Abstract: | With the successful entry of the Mars Odyssey spacecraft into mapping orbit in early 2002 (Ls=330), the Thermal Emission Imaging System (THEMIS) joins Mars Global Surveyor TES in monitoring Martian atmospheric temperatures and aerosol opacity using thermal infrared remote sensing from Mars orbit. The THEMIS 15-micron channel (Band 10) can be used in the same way as the Viking IRTM 15-micron channel to give temperatures integrated over a broad portion of the atmosphere centered at about 0.6 mbar. The characteristic signatures of dust and water ice aerosols that are clearly evident in the other THEMIS channels can be used to estimate atmospheric opacity. Here, we give an overview of the latest atmospheric results from both THEMIS and TES during the northern winter and spring seasons (Ls=270-90). Included during this period were the decay of the 2001a planet-encircling dust storm, the growth and establishment of the low-latitude aphelion water-ice cloud belt, and the annual globally-averaged minima of water vapor, dust, and atmospheric temperature. |
| Title: | Divergent Evolution Among Earth-like Planets: The Case for Venus Exploration |
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| Authors: | Crisp, D.; Allen, M. A.; Anicich, V. G.; Arvidson, R. E.; Atreya, S. K.; Baines, K. H.; Banerdt, W. B.; Bjoraker, G. L.; Bougher, S. W.; Campbell, B. A.; Carlson, R. W.; Chin, G.; Chutjian, A.; Clancy, R. T.; Clark, B. C.; Cravens, T. E.; del Genio, A. D.; Esposito, L. W.; Fegley, B.; Flasar, M.; Fox, J. L.; Gierasch, P. J.; Goody, R. M.; Grinspoon, D. H.; Gulkis, S.; Hansen, V. L.; Herrick, R. R.; Huestis, D. L.; Hunten, D. M.; Janssen, M. A.; Jenkins, J.; Johnson, C. L.; Keating, G. M.; Kliore, A. J.; Limaye, S. S.; Luhmann, J. G.; Lunine, J. I.; Mahaffy, P.; McGovern, P. J.; Meadows, V. S.; Mills, F. P.; Niemann, H. B.; Owen, T. C.; Oyama, K. I.; Pepin, R. O.; Plaut, J. J.; Reuter, D. C.; Richardson, M. I.; Russell, C. T.; Saunders, R. S.; Schofield, J. T.; Schubert, G.; Senske, D. A.; Shepard, M. K.; Slanger, T. G.; Smrekar, S. E.; Stevenson, D. J.; Titov, D. V.; Ustinov, E. A.; Young, R. E.; Yung, Y. L. |
| Affiliation: | AA(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA), AB(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA), AC(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA), AD(Department of Earth and Planetary Science, Washington University, St Louis, MO), AE(Department of Atmospheric, Ocean, and Space Sciences, University of Michigan, Ann Arbor, MI), AF(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA), AG(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA), AH(NASA Goddard Space Flight Center, Greenbelt, MD), AI(Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ), AJ(National Air and Space Museum, Washington, DC), AK(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA), AL(NASA Goddard Space Flight Center, Greenbelt, MD), AM(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA), ! AN(Space Science Institute, Boulder, CO), AO(Lockheed Martin Astronautics, Denver, CO), AP(Department of Physics and Astronomy, University of Kansas, Lawrence, KS), AQ(NASA Goddard Institute for Space Studies, New York, NY), AR(Atmospheric and Space Physics Laboratory, University of Colorado, Boulder, CO), AS(Department of Earth and Planetary Science, Washington University, St Louis, MO), AT(NASA Goddard Space Flight Center, Greenbelt, MD), AU(Department of Physics, Wright State University, Dayton, OH), AV(Department of Astronomy, Cornell University, Ithaca, NY), AW(Division of Applied Sciences, Harvard University, Cambridge, MA), AX(Southwest Research Institute, Boulder, CO), AY(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA), AZ(Department of Geological Sciences, Southern Methodist University, Dallas, TX), BA(Lunar and Planetary Institute, Houston, TX), BB(Molecular Physics Laboratory, SRI International, Menlo Park, CA), BC(Lunar and Planetary! Laboratory, University of Arizona, Tucson, AZ), BD(Jet Propul! sion Lab oratory, California Institute of Technology, Pasadena, CA), BE(SETI Institute, Mountain View, CA), BF(Scripps Institute for Oceanography, University of California, San Diego, CA), BG(George Washington University at NASA Langley Research Center, Hampton VA), BH(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA), BI(Space Science and Engineering Center, University of Wisconsin-Madison, Madison, WI), BJ(Space Science Laboratory, University of California, Berkeley, CA), BK(Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ), BL(NASA Goddard Space Flight Center, Greenbelt, MD), BM(Lunar and Planetary Institute, Houston, TX), BN(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA), BO(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA), BP(NASA Goddard Space Flight Center, Greenbelt, MD), BQ(Institute for Astronomy, University of Hawaii, Honolulu, HI), BR(Institute of Space and Aeronautical S! cience, Japan), BS(School of Physics and Astronomy, University of Minnesota, Minneapolis, MN), BT(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA), BU(NASA Goddard Space Flight Center, Greenbelt, MD), BV(Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA), BW(Dept Earth and Space Sciences, University of California, Los Angeles, CA), BX(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA), BY(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA), BZ(Dept Earth and Space Sciences, University of California, Los Angeles, CA), CA(NASA Headquarters, Washington, DC), CB(Department of Geography and Earth Science, Bloomsburg University, Bloomsburg, PA), CC(Molecular Physics Laboratory, SRI International, Menlo Park, CA), CD(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA), CE(Geological and Planetary Sciences, California Institute of Technology, Pas! adena, CA), CF(Max-Planck-Institut fuer Aeronomie, Katlenburg-! Lindau, Germany), CG(Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA), CH(NASA Ames Research Center, Moffett Field, CA), CI(Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA) |
| Journal: | The Future of Solar System Exploration (2003-2013) -- Community Contributions to the NRC Solar System Exploration Decadal Survey. ASP Conference Proceedings, Vol. 272. Edited by Mark V. Sykes. ISBN: 1-58381-113-3. San Francisco, Astronomical Society of the Pacific, 2002, pp. 5-34. |
| Publication Date: | Aug 2002 |
| Origin: | AUTHOR |
| Bibliographic Code: | 2002ASPC..272....5C |
| Abstract: | The planet Venus is our most Earth-like neighbor in size, mass, and distance from the sun. In spite of these similarities, and the intense scrutiny that it received early in the space age, the Venus surface and atmosphere are characterized by some of the most enigmatic features seen anywhere in the solar system. A reinvigorated Venus exploration program is essential to the development of a comprehensive understanding of the origin and evolution of Earth-like terrestrial planets. The present NASA inner planets strategy, which focuses exclusively on Mars, will provide an incomplete, and possibly misleading description of processes that produce these objects. If Venus-like terrestrial planets are common, this approach will also impede efforts to interpret observations of extrasolar terrestrial planets, which are expected to become available by the end of the decade. Here, we propose a Venus exploration program that has been designed to explain the origin and divergent evolution of the interiors, surfaces, and atmospheres of the terrestrial planets in our solar system, and provide greater insight into the conditions that may affect the habitability of terrestrial planets in other solar systems. |
| Title: | Sand Transport in Proctor Crater on Mars Based on Dune Morphology and Mesoscale Modeling |
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| Authors: | Fenton, L. K.; Richardson, M. I.; Toigo, A. D. |
| Journal: | 33rd Annual Lunar and Planetary Science Conference, March 11-15, 2002, Houston, Texas, abstract no.1953 |
| Publication Date: | Mar 2002 |
| Origin: | LPI |
| Bibliographic Code: | 2002LPI....33.1953F |
| Abstract: | The goal of this work is to determine the recent sedimentary and climate history of Proctor Crater. The dunes are formed in a bidirectional wind regime that matches the modeled circulation patterns of the current climate. |
| Title: | Advances in understanding of the Martian climate |
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| Authors: | Richardson, Mark I. |
| Journal: | In: Highlights of Astronomy, Vol. 12, as presented at the XXIVth General Assembly of the IAU - 2000 [Manchester, UK, 7 - 18 August 2000]. Edited by H. Rickman. San Francisco, CA: Astronomical Society of the Pacific, ISBN 1-58381-086-2, 2002, p. 637 |
| Publication Date: | n/a 2002 |
| Origin: | ARI |
| Keywords: | Mars, Climate |
| Abstract Copyright: | IAU |
| Bibliographic Code: | 2002HiA....12..637R |
| Abstract: | Not Available |
| Title: | Comprehensive Simulation Of The Current Mars Water Cycle |
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| Authors: | Rodin, A. V.; Wilson, R. J.; Richardson, M. I. |
| Journal: | EGS XXVII General Assembly, Nice, 21-26 April 2002, abstract #4651 |
| Publication Date: | Jan 2002 |
| Origin: | EGU |
| Bibliographic Code: | 2002EGSGA..27.4651R |
| Abstract: | The water cycle is one of the most important mechanisms shaping the current climate of Mars. Recent progress in climate monitoring with the Mars Global Surveyor's TES instrument has revealed new features of the water cycle, including its strong coupling with the atmospheric circulation. We have implemented comprehensive simulation of hydrological processes in the GFDL Mars General Circulation Model, including at- mospheric transport and microphysics of water ice clouds and their coupling with dust and radiative balance. It is shown that the seasonal migration of water between polar regions and tropics is strongly influenced by the microphysical properties of clouds and the Hadley cell circulation. The intensity and zonal structure of this circulation is, in turn, sensitive to radiative forcing by aerosols. In order to determine how various mechanisms influence the water cycle, we present sensitivity studies against dust load- ing and microphysical processes in clouds. Multiannual simulations with a reduced self-consistent microphysical scheme have been carried out to address the stability of the current surface water inventory and the origin of its prominent interhemispherical asymmetry. This work has been supported by NASA JURRISS program |