DOCSLIB.ORG

Sand Flux Estimates and Aeolian-Driven Landscape Evolution on Mars

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Sand Flux Estimates and Aeolian-Driven Landscape Evolution on Mars Lunar and Planetary Science XLVIII (2017) 2627.pdf SAND FLUX ESTIMATES AND AEOLIAN-DRIVEN LANDSCAPE EVOLUTION ON MARS. M. Cho- jnacki1, A. C. Urso1, M. E. Banks2, L. L. Tornabene3 and N. T. Bridges4. 1Lunar and Planetary Lab, University of Arizona, Tucson, AZ ([email protected]); 2Planetary Science Institute, Tucson, AZ; 3Centre for Plane- tary Science & Exploration (CPSX), Western University; 4Johns Hopkins University, APL, Laurel, MD, USA. Introduction and Motivation: The last decade of Mars years) producing units of m3 m-1 yr-1 in time units Mars exploration has revealed that the current (tenu- of Earth years [11]. See [7] for full methodology. ous) atmosphere is capable of moving surface sedi- Using sediment fluxes and the abrasion susceptibil- ment. Notably, low albedo, aeolian sand ripples and ity (Sa) of rocks (mass of sand needed to erode mass of dunes are actively migrating across the surface today, rock [12]) erosion rates were estimated. The method- which has implications for local wind regimes and ology and assumptions (e.g., Sa for basalt at impact landscape evolution [for a review see 1]. Indeed, aeoli- threshold, mean trajectory height, interdune fluxes, an processes have likely been the predominant geo- etc.) described in Bridges et al. [4] were used. Pressure morphic agent for most of Mars’ history, in contrast to estimates were done using an empirical expression as a the Earth where aqueous processes dominate. function of season and elevation [13]. [14] Global studies have shown geographic variations in Results: Thirty-six sand dune monitoring sites bedform activity status (active, migrating, no detec- across Mars are located within craters, canyons, fossae, tion) based on change detection using high resolution patera, basins, and extracrater terrain (Fig. 1). Average orbital images [1–3]. More detailed investigations have migration rates reach up to 2.1 m/yr for all dune fields quantified migration and volumetric sand fluxes, which (highest rates were detected in Endeavour crater [6]), are independent of dune size, but are limited to just a and the average across all sites was 0.5 m/yr (std. dev. few locations [4–7]. These measurements are im- +/-0.5 m/yr). These rates coupled with associated dune portant, as they relate to surface erosion and its poten- heights (1-90 meters tall) yield sand fluxes of 0.8-17.6 tial exposure of desirable units for in situ analysis [8]. m3 m-1 yr-1 (Fig. 2) – individual dunes may range up to Here, we investigate and quantify dune migration >25 m3 m-1 yr-1. The average and standard deviations trends across Mars, utilizing temporal image series and for all sites investigated are 6.5 +/-4.9 m3 m-1 yr-1. For topography. Related questions include: What are the context, these flux values are often an order of magni- spatial variations of aeolian bedform transport rates tude less than for dune fields on Earth, but larger than and volumetric sediment fluxes? How does the esti- earlier reports for Mars [4, 7]. Dunes fields with the mated abrasion (or erosion) rates vary for these sites highest fluxes are located in the North Polar Erg, Nili and how might they have changed over time? Patera/Fossae region, Mawrth Vallis (e.g., Fig. 3), and Data Sets and Methods: To assess aeolian activi- Hellespontus, whereas low and moderate fluxes are ty, we have utilized images acquired by the High Reso- located in Meridiani, Valles Marineris, and the South- lution Imaging Science Experiment (HiRISE) [9] cam- ern Highlands locations. In contrast, Banks et al. [3] era (0.25–1 m/pix). For image orthorectification and only found ripple movement or no detections for dune dune topography, Digital Terrain Models (DTMs) (at 1 sites south of 57°S latitude (Fig. 1). m post spacing) were constructed from HiRISE stereo Abrasion rates of local basaltic bedrock are esti- pairs [10]. Lee front advancements were recorded in mated to be 0.1–25 µm/yr for flat ground and 1–120 several locations per dune then averaged. Volumetric µm/yr for a vertical rock face. For example, swiftly sand fluxes of the dunes can be obtained using the migrating barchan dunes in McLaughlin crater (Fig. 3) product of the estimated height and the bedform dis- are estimated to be eroding the surface on the high end placement over the intervening time (typically 2–3 of this range (2–80 µm/yr). Fig. 1. Map of Mars showing locations of dune field monitoring sites with (average per site) crest flux estimates (units of m3 m-1 yr-1). Triangles indi- cate bedform activity sta- tus for ripples and dunes [3]. Dune field distribution is shown in red [14]. Base map is MOLA shaded relief with colorized ele- vation. Lunar and Planetary Science XLVIII (2017) 2627.pdf Discussion: Results demonstrate substantial geo- es we can expect at least an order of magnitude in- graphic heterogeneity in dune sediment fluxes across crease in abrasion rates. the planet and per site. High sand fluxes are observed As abrasion rates are only for basaltic target rock, at all the high northern latitude (>70°) sites. While composition is likely an important factor not accounted some dune slipface movement there is driven by sea- for in our estimates. The abrasion susceptibility of sonal CO2 frost, volume estimates suggest that this softer sedimentary terrains composed of clays and sul- process contributes no more than 20% of the local sand fates will allow for greater erosion. Additionally, re- movement [15]. In contrast, sites in the south (<57°S) cent studies have suggested certain geomorphic are often static [3], which is consistent with the hy- boundary conditions are more conducive to higher pothesized stabilization of high southern latitude dune fluxes and erosion rates (e.g., crater degradation state, fields following climate change [16]. Mid- and tropi- presence of rugged adjacent topography [7]). cal-latitude sites can vary substantially, but equatorial Aeolian-driven landscape evolution on Mars is sites tend to have low to moderate fluxes (<9 m3 m-1 yr- likely to be accentuated or muted given certain combi- 1). It is important to note, fluxes are not necessarily nations of sediment fluxes, atmospheric properties, correlated with migration rates. For example, dunes surrounding mesoscale topography, and terrain geolo- across Meridiani are some of the fastest on the planet gy. Future efforts will be employed in understanding (>1 m/yr), but because of their modest sizes have low these factors and the overall distribution of sand overall fluxes [6, 7]. Alternatively, slowly advancing movement across Mars. Syrtis Major barchans, dunes not initially detected as active using shorter baseline images [2], show moder- ate fluxes due to their larger sizes (>80 m). Monitoring site terrains are frequently found in the presence of streamlined landforms such as knobs and yardangs, often carved out of sedimentary units, where wind erosion and abrasion are likely formation agents. Estimated abrasion rates reported above are similar, but greater than earlier independent assessments. Sand abrasion will be greater during periods of higher at- mospheric pressure as the threshold friction speed would be depressed along with the greater occurrence of high winds [17]. For example, high frequency sea- sonal monitoring of the Nili Patera dune field [5] showed the greatest ripple fluxes during perhelion (es- Figure 3. Displacement map of rapidly advancing timated local pressure of 6.3 mbar), while they were barchans (~1 m/yr) in McLaughlin crater. Red-yellow lowest during aphelion (5.3 mbar). This modest change areas indicate darkening (lee-front advancement), in pressure resulted in a three-fold increase in sand while purple-green show lightening (stoss-side ad- fluxes [5]. As atmospheric pressure rises during peri- vancement) over 4 Mars years. Scale bar is 250 m. ods of higher orbital obliquity so will sand fluxes and Acknowledgments: This research was supported in abrasion rates. For example, doubling the perhelion part by NASA MDAP Grants NNH14ZDA001N and the pressure to 12.6 mbar increase fluxes substantially, HiRISE/MRO mission. We would like to thank UofA assuming a linear relationship. With these greater flux- students and staff for assistance with DTM production. References: [1] Bridges N. et al. (2013) Aeolian Res., 9, 133–151. [2] Bridges N. et al. (2011) Geology, 40, 31– 34. [3] Banks M. et al. (This conference). [4] Bridges N. et al. (2012) Nature, 485, 339–342. [5] Ayoub F. et al. (2014) Nat Comm., 5, 10.1038/ncomms6096. [6] Cho- jnacki M. et al. (2015) Icarus, 251, 275–290. [7] Cho- jnacki M. et al. (in press.) Aeolian Res. [8] Williams J. and M. Rice (2016) GSA-Denver, 48, abs. 109-0. [9] McEwen A. et al. (2007) JGR Plan., 112, E05S02. [10] Kirk, R. et al. (2008) JGR Plan.,, 113, E00A24. [11] Ould Ahmedou D. et al. (2007) JGR Earth Surf., 112, F02016. [12] Greeley, R. (1982) JGR Sol. Earth, 113, E00A24. [13] Withers, P. (2012) Space Sci. Rev., 170, 837–860. [14] Hayward, R. (2014) Icarus, 230, 38–46. [15] Diniega Figure 2. Log-log plot of (average) migration rates vs. S. et al (This conference). [16] Fenton L. and R. Hayward heights for 36 dune fields monitoring sites across Mars (2010) Geomorp., 121, 98–121. [17] Armstrong J. and C. (Fig. 1). Diagonal lines are isopleths of sand flux. Leovy (2005), Icarus, 176, 57–74. .
Load more

Recommended publications
  • Thermal Creep Assisted Dust Lifting on Mars
    Thermal creep assisted dust lifting on Mars: Wind tunnel experiments for the entrainment threshold velocity Markus Küpper, Gerhard Wurm ∗ August 1, 2015 In this work we present laboratory measurements on the ils, several further ideas were proposed. Certain types of reduction of the threshold friction velocity necessary for particle inventory like volcanic glass or aggregated parti- lifting dust if the dust bed is illuminated. Insolation of cles are more susceptible for pick up at lower wind speeds. a porous soil establishes a temperature gradient. At low The big, light-weight particles can roll over the surfaces ambient pressure this gradient leads to thermal creep gas which breaks the adhesion before the particles are then flow within the soil. This flow leads to a sub-surface over- lifted (de Vet et al. 2014; Merrison et al. 2007). Charging pressure which supports lift imposed by wind. The wind has also been discussed as a mechanism to explain the high tunnel was run with Mojave Mars Simulant and air at 3, 6 entrainment rates (Kok et al. 2006). If a number of parti- and 9 mbar, to cover most of the pressure range at martian cles are ejected at low wind speed the threshold wind speed surface levels. Our first measurements imply that the in- will also be lowered due to the reimpacting grains. Steady solation of the martian surface can reduce the entrainment state saltation might then occur at lower wind speeds (Kok threshold velocity between 4 % and 19 % for the conditions 2010). For a review on sand and dust entrainment we refer sampled with our experiments.
    [Show full text]
  • Dark Dunes on Mars
    CHAPTER II: PLANET MARS – THE BACKGROUND Like Earth, its neighbour planet, Mars, is a terrestrial planet with a solid surface, an atmosphere, two ice-covered pole caps, and not one but two moons (Phobos and Deimos). Some differences, such as a greater distance to the sun, a smaller diameter, a thinner atmosphere, and the longer duration of a year distinguish Mars from the Earth, not to forget the absence of life…so far. Nevertheless, there are many correlations between terrestrial and Martian geological and geomorphological processes, permitting researchers to apply knowledge from terrestrial studies more or less directly to Mars. However, a closer look reveals that the dissimilarities, though few, can make fundamental differences in process background and development. The following chapter provides a brief but necessary insight into the geological and physical background of this planet, imparting to the reader some fundamental knowledge about Mars, which is useful for understanding this work. Fig. 1 presents an impression of Mars viewed from space. Figure 1: The planet Mars: a global view (Viking 1 Orbiter mosaic [NASA]). Chapter II Planet Mars – The Background 5 Table 1 provides a summary of some major astronomical and physical parameters of Mars, giving the reader an impression of the extent to which they differ from terrestrial values. Table 1: Parameters of Mars [Kieffer et al., 1992a]. Property Dimension Orbit 227 940 000 km (1.52 AU) mean distance to the Sun Diameter 6794 km Mass 6.4185 * 1023 kg 3 Mean density ~3.933 g/cm Obliquity
    [Show full text]
  • The Geological History of Nili Patera, Mars 10.1002/2015JE004795 P
    PUBLICATIONS Journal of Geophysical Research: Planets RESEARCH ARTICLE The geological history of Nili Patera, Mars 10.1002/2015JE004795 P. Fawdon1, J. R. Skok2, M. R. Balme1, C. L. Vye-Brown3, D. A. Rothery1, and C. J. Jordan4 Key Points: 1Department of Physical Sciences, The Open University, Walton Hall, Milton Keynes, UK, 2Department of Geology & • A new CTX-scale map details the 3 geological history of Nili Patera Geophysics, Louisiana State University, Baton Rouge, Louisiana, USA, British Geological Survey, Murchison House, 4 • Magmatism includes effusive basalts, Edinburgh, UK, British Geological Survey, Nottingham, UK magmatic intrusion, and ignimbrite(s) • Volcanism and water suggest habitable environments in highland patera caldera Abstract Nili Patera is a 50 km diameter caldera at the center of the Syrtis Major Planum volcanic province. The caldera is unique among Martian volcanic terrains in hosting: (i) evidence of both effusive and explosive Supporting Information: volcanism, (ii) hydrothermal silica, and (iii) compositional diversity from olivine-rich basalts to silica-enriched • Figures S1 and S2 units. We have produced a new geological map using three mosaicked 18 m/pixel Context Camera digital • Map S1 elevation models, supplemented by Compact Remote Imaging Spectrometer for Mars Hyperspectral data. Correspondence to: The map contextualizes these discoveries, formulating a stratigraphy in which Nili Patera formed by trapdoor P. Fawdon, collapse into a volcanotectonic depression. The distinctive bright floor of Nili Patera formed either as part of a [email protected] felsic pluton, exposed during caldera formation, or as remnants of welded ignimbrite(s) associated with caldera formation—both scenarios deriving from melting in the Noachian highland basement.
    [Show full text]
  • Bedform Migration on Mars: Current Results and Future Plans
    Aeolian Research xxx (2013) xxx–xxx Contents lists available at SciVerse ScienceDirect Aeolian Research journal homepage: www.elsevier.com/locate/aeolia Review Article Bedform migration on Mars: Current results and future plans ⇑ Nathan Bridges a, , Paul Geissler b, Simone Silvestro c, Maria Banks d a Johns Hopkins University, Applied Physics Laboratory, 200-W230, 11100 Johns Hopkins Road, Laurel, MD 20723, USA b US Geological Survey, Astrogeology Science Center, 2255 N. Gemini Drive, Flagstaff, AZ 86001-1698, USA c SETI Institute, 189 Bernardo Ave., Suite 100, Mountain View, CA 94043, USA d Center for Earth and Planetary Studies, Smithsonian National Air and Space Museum, Washington, DC 20013-7012, USA article info abstract Article history: With the advent of high resolution imaging, bedform motion can now be tracked on the Martian surface. Received 30 July 2012 HiRISE data, with a pixel scale as fine as 25 cm, shows displacements of sand patches, dunes, and ripples Revised 19 February 2013 up to several meters per Earth year, demonstrating that significant landscape modification occurs in the Accepted 19 February 2013 current environment. This seems to consistently occur in the north polar erg, with variable activity at Available online xxxx other latitudes. Volumetric dune and ripple changes indicate sand fluxes up to several cubic meters per meter per year, similar to that found in some dune fields on Earth. All ‘‘transverse aeolian ridges’’ Keywords: are immobile. There is no relationship between bedform activity and coarse-scale global circulation mod- Mars els, indicating that finer scale topography and wind gusts, combined with the predicted low impact Dunes Ripples threshold on Mars, are the primary drivers.
    [Show full text]
  • Wind-Driven Erosion and Exposure Potential at Mars 2020 Rover
    PUBLICATIONS Journal of Geophysical Research: Planets RESEARCH ARTICLE Wind-Driven Erosion and Exposure Potential 10.1002/2017JE005460 at Mars 2020 Rover Candidate-Landing Sites Special Section: Matthew Chojnacki1 , Maria Banks2 , and Anna Urso1 5th International Planetary Dunes Workshop Special Issue 1Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA, 2NASA Goddard Space Flight Center, Greenbelt, MD, USA Key Points: • Candidate-landing sites for the Mars ’ 2020 Rover mission were assessed for Abstract Aeolian processes have likely been the predominant geomorphic agent for most of Mars history potential erosion by active eolian and have the potential to produce relatively young exposure ages for geologic units. Thus, identifying local bedforms evidence for aeolian erosion is highly relevant to the selection of landing sites for future missions, such as • Of the three downselected sites NE Syrtis then Jezero crater showed the the Mars 2020 Rover mission that aims to explore astrobiologically relevant ancient environments. Here we most evidence for ongoing sand investigate wind-driven activity at eight Mars 2020 candidate-landing sites to constrain erosion potential at transport and erosion potential these locations. To demonstrate our methods, we found that contemporary dune-derived abrasion rates • The Columbia Hills site lacked evidence for sand movement from were in agreement with rover-derived exhumation rates at Gale crater and could be employed elsewhere. local bedforms, suggesting that The Holden crater candidate site was interpreted to have low contemporary erosion rates, based on the current abrasion rates are low presence of a thick sand coverage of static ripples. Active ripples at the Eberswalde and southwest Melas sites may account for local erosion and the dearth of small craters.
    [Show full text]
  • Basaltic Sand Ripples at Eagle Crater As Indirect Evidence for the Hysteresis Effect in Martian Saltation ⇑ H
    Icarus 230 (2014) 143–150 Contents lists available at ScienceDirect Icarus journal homepage: www.elsevier.com/locate/icarus Basaltic sand ripples at Eagle Crater as indirect evidence for the hysteresis effect in martian saltation ⇑ H. Yizhaq a, , J.F. Kok b, I. Katra c a Solar Energy and Environmental Physics, BIDR, Ben-Gurion University of the Negev, Midreshet Ben-Gurion, Israel b Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, California, USA c Department of Geography and Environmental Development, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel article info abstract Article history: The rover Opportunity documented small basaltic sand ripples at the bottom of Eagle Crater, Meridiani Available online 14 August 2013 Planum on Mars. These ripples are composed of fine basaltic sand (100 lm diameter) and their average wavelength and height are 10 cm and 1 cm, respectively. Present theories on the transition between sal- Keywords: tation and suspension predict that such light particles are suspended by turbulence at the fluid threshold, Mars which is the minimum wind speed required to initiate saltation. Consequently, the existence of these Aeolian processes 100 lm ripples on Mars indicates that either current suspension theories are incorrect, or that saltation Mars surface can take place at wind speeds substantially below the fluid threshold. Indeed, recent studies point to the occurrence of hysteresis in martian saltation. That is, once initiated, hysteresis can be maintained at much lower wind speeds than the fluid threshold. We investigated the possible role of hysteresis in the formation of fine-grained ripples on Mars by coupling, for the first time, a detailed numerical saltation model (COMSALT) with a dynamic model for sand ripple formation.
    [Show full text]
  • Understanding Ripple and Whole-Dune Motion at Active Martian Dune Fields
    50th Lunar and Planetary Science Conference 2019 (LPI Contrib. No. 2132) 3169.pdf Understanding ripple and whole-dune motion at active Martian dune fields. K. P. Roback1, K. D. Runyon2, J. P. Avouac1, C. E. Newman3 and F. Ayoub4 1California Institute of Technology, Pasadena, CA, USA (kro- [email protected]), 2Johns Hopkins APL, Laurel, MD, USA, 3Aeolis Research, Pasadena, CA 4Jet Propulsion La- boratory, Pasadena, CA, USA. Introduction: Recent observations of Martian dune fields by the Mars Reconnaissance Orbiter’s HiRISE camera have documented the existence and present-day movement of meter-scale ripples on sand dunes and sheets [1, 2, 3, 4, 5]. Measurements of whole-dune sand flux have been made [2, 4, 5, 6], but this motion has been difficult to constrain due to the slow rate of sand dunes. Since these earlier studies, the length of timeseries of imagery collected at some Mar- tian dune fields has increased to over 10 Earth years. We apply long timeseries imagery at three Martian dune fields (Nili Patera, Meroe Patera, and Gale Crater’s Bagnold Dunes) to study annual and interan- nual variability in sand flux, and compare sand fluxes Fig. 1: View of the pattern of ripple displacement de- associated with ripples to sand fluxes associated with rived from COSI-Corr analysis, shown here as a vector movement of entire dunes. We further use patterns of field, on a barchan dune in the Nili Patera dune field. annual variability in sand fluxes to reveal seasonal wind trends and to calculate effective shear stress sand motion from our ripple-flux results and thresholds for sand motion initiation.
    [Show full text]
  • Aeolian Abrasion of Rocks As a Mechanism to Produce Methane in the Martian Atmosphere.', ScientiC Reports, 9 (1)
    Durham Research Online Deposited in DRO: 19 June 2019 Version of attached le: Published Version Peer-review status of attached le: Peer-reviewed Citation for published item: Sa, E. and Telling, J. and Parnell, J. and Chojnacki, M. and Patel, M. R. and Real, J. and Blamey, N. J. F. and Payler, S. and Cockell, C. S. and Davies, L. and Boothroyd, I. M. and Worrall, F. and Wadham, J. L. (2019) 'Aeolian abrasion of rocks as a mechanism to produce methane in the Martian atmosphere.', Scientic reports, 9 (1). p. 8229. Further information on publisher's website: https://doi.org/10.1038/s41598-019-44616-2 Publisher's copyright statement: This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. Additional information: Use policy The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that: • a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.
    [Show full text]
  • Quantified Aeolian Dune Changes on Mars Derived from Repeat Context Camera Images
    Davis Joel M. (Orcid ID: 0000-0003-3522-7910) Grindrod Peter Martin (Orcid ID: 0000-0002-0934-5131) Boazman Sarah J. (Orcid ID: 0000-0003-4694-0818) Quantified Aeolian Dune Changes on Mars Derived from Repeat Context Camera Images Joel M. Davis1, Peter M. Grindrod1, Sarah J. Boazman1,2, Pieter Vermeesch2, Thomas Baird2 1Department of Earth Sciences, Natural History Museum, London, SW7 5BD, UK 2Department of Earth Sciences, University College London, London, WC1E 6BT, UK Corresponding author: Joel Davis ([email protected]) Key Points: Martian dune displacement is observed over medium- and long-term baselines (7-11 Earth years) in CTX images at six sites Dune migration rates and sand fluxes can be quantified in CTX using SOCET SET and COSI-Corr and compare well to results from HiRISE images The use of CTX has advantages and disadvantages, and the combined use of HiRISE and CTX will be beneficial This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1029/2019EA000874 ©2019 American Geophysical Union. All rights reserved. Abstract Aeolian systems are active across much of the surface of Mars and quantifying the activity of bedforms is important for understanding the modern and recent martian environment. Recently, the migration rates and sand fluxes of dunes and ripples has been precisely measured using repeat High Resolution Imaging Science Experiment (HiRISE) images. However, the limited areal extent of HiRISE coverage means that only a small area can be targeted for repeat coverage.
    [Show full text]
  • Edge-Detection Applied to Moving Sand Dunes on Mars
    Edge-detection applied to moving sand dunes on Mars Amelia Carolina Sparavigna Department of Applied Science and Technology, Politecnico di Torino, Torino, Italy Abstract: Here we discuss the application of an edge detection filter, the Sobel filter of GIMP, to the recently discovered motion of some sand dunes on Mars. The filter allows a good comparison of an image HiRISE of 2007 and an image of 1999 recorded by the Mars Global Surveyor of the dunes in the Nili Patera caldera, measuring therefore the motion of the dunes on a longer period of time than that previously investigated. Keywords : Edge detection, Sobel filter, GIMP, Image processing, Google Mars, Dune motion, Satellite images, HiRISE, Mars Reconnaissance Orbiter, Mars Global Surveyor. 1. Introduction Since the edge detection approach is often involved in the digital image processing, we have several methods that we can apply to satellite images to detect, for instance, the boundaries of some landforms and their evolution. Classical procedures are based on the filtering with gradients and on operators such as those of Roberts, Previt and Sobel [1]. More sophisticated procedures are based on the operators of Hueckel and Humel, and on the estimation of statistical characteristics of the image as in the LoG and Canny detectors [1]. Besides, these procedures, several new methods have been proposed on grey-scale and color images; among them for instance, those proposed in [1-4]. Some edge detection filters are also available in the GNU image manipulation program (GIMP). They are the edge, Laplace, Neon, Sobel and the difference of Gaussians, the details of which are given in [5].
    [Show full text]
  • Mars: an Introduction to Its Interior, Surface and Atmosphere
    MARS: AN INTRODUCTION TO ITS INTERIOR, SURFACE AND ATMOSPHERE Our knowledge of Mars has changed dramatically in the past 40 years due to the wealth of information provided by Earth-based and orbiting telescopes, and spacecraft investiga- tions. Recent observations suggest that water has played a major role in the climatic and geologic history of the planet. This book covers our current understanding of the planet’s formation, geology, atmosphere, interior, surface properties, and potential for life. This interdisciplinary text encompasses the fields of geology, chemistry, atmospheric sciences, geophysics, and astronomy. Each chapter introduces the necessary background information to help the non-specialist understand the topics explored. It includes results from missions through 2006, including the latest insights from Mars Express and the Mars Exploration Rovers. Containing the most up-to-date information on Mars, this book is an important reference for graduate students and researchers. Nadine Barlow is Associate Professor in the Department of Physics and Astronomy at Northern Arizona University. Her research focuses on Martian impact craters and what they can tell us about the distribution of subsurface water and ice reservoirs. CAMBRIDGE PLANETARY SCIENCE Series Editors Fran Bagenal, David Jewitt, Carl Murray, Jim Bell, Ralph Lorenz, Francis Nimmo, Sara Russell Books in the series 1. Jupiter: The Planet, Satellites and Magnetosphere Edited by Bagenal, Dowling and McKinnon 978 0 521 81808 7 2. Meteorites: A Petrologic, Chemical and Isotopic Synthesis Hutchison 978 0 521 47010 0 3. The Origin of Chondrules and Chondrites Sears 978 0 521 83603 6 4. Planetary Rings Esposito 978 0 521 36222 1 5.
    [Show full text]
  • Late Amazonian) Enhanced Backweathering Rates on Mars : Paracratering Evidence from Gully Alcoves.', Journal of Geophysical Research : Planets., 120 (12)
    Durham Research Online Deposited in DRO: 01 March 2017 Version of attached le: Published Version Peer-review status of attached le: Peer-reviewed Citation for published item: De Haas, T. and Conway, S. J. and Krautblatter, M. (2015) 'Recent (Late Amazonian) enhanced backweathering rates on Mars : paracratering evidence from gully alcoves.', Journal of geophysical research : planets., 120 (12). pp. 2169-2189. Further information on publisher's website: https://doi.org/10.1002/2015je004915 Publisher's copyright statement: de Haas, T., S. J. Conway, and M. Krautblatter (2015), Recent (Late Amazonian) enhanced backweathering rates on Mars: Paracratering evidence from gully alcoves, Journal of Geophysical Research: Planets, 120(12), 2169-2189, DOI: 10.1002/2015JE004915. To view the published open abstract, go to https://doi.org/ and enter the DOI. Additional information: Use policy The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that: • a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders. Please consult the full DRO policy for further details. Durham University Library, Stockton Road, Durham DH1 3LY, United Kingdom Tel : +44 (0)191 334 3042 | Fax : +44 (0)191 334 2971 https://dro.dur.ac.uk Journal of Geophysical Research: Planets RESEARCH ARTICLE Recent (Late Amazonian) enhanced backweathering rates 10.1002/2015JE004915 on Mars: Paracratering evidence from gully alcoves Key Points: 1 2 3 • Late Amazonian backweathering rates Tjalling de Haas , Susan J.
    [Show full text]