Quantified Aeolian Dune Changes on Mars Derived From Repeat Context Camera Images

Joel M Davis,Pieter Vermeesch,Peter M Grindrod,Thomas Baird,Sarah J Boazman

doi:10.1029/2019ea000874

Joel M Davis, Pieter Vermeesch + Show 3 more

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https://doi.org/10.1029/2019ea000874

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Abstract

AbstractAeolian 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 have 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. Context Camera (CTX) images, although lower in spatial resolution, have wider spatial coverage, meaning that dune migration can potentially be monitored over larger areas. We used time series, coregistered CTX images and digital elevation models to measure dune migration rates and sand fluxes at six sites: Nili Patera, Meroe Patera, two sites at Herschel crater, McLaughlin crater, and Hellespontus Montes. We observed dune displacement in the CTX images over long‐term baselines (7.5–11 Earth years; 4–6 Mars years). Bedform activity has previously been measured at all these sites using HiRISE, which we used to validate our results. Our dune migration rates (0.2–1.1 m/EY) and sand fluxes (2.4–11.6 m3 m−1 EY−1) compare well to measurements made with HiRISE. The use of CTX in monitoring dune migration has advantages (wider spatial coverage, faster processing time) and disadvantages (ripples not resolved, digital elevation model dune heights may be underestimates); the future combined use of HiRISE and CTX is likely to be beneficial.

Highlights

Aeolian processes are active across much of the surface of Mars (e.g., Bourke et al, 2008; Bridges, Ayoub, et al, 2012) and are considered one of the predominant agents for landscape modification in nonpolar regions, under the current climate conditions (e.g., Bridges et al, 2013)
Our dune migration rates (0.2–1.1 m/EY) and sand fluxes (2.4–11.6 m3 m−1 EY−1) compare well to measurements made with High Resolution Imaging Science Experiment (HiRISE)
CTX image pairs were selected such that the stereo convergence angle was ≥15° and that images were acquired in close succession, under similar imaging conditions, and with the fewest shadows associated with the dunes

Summary

Introduction

Aeolian processes are active across much of the surface of Mars (e.g., Bourke et al, 2008; Bridges, Ayoub, et al, 2012) and are considered one of the predominant agents for landscape modification in nonpolar regions, under the current climate conditions (e.g., Bridges et al, 2013) This is evident from the movement of aeolian bedforms (dunes and ripples) observed in high‐resolution orbital images (e.g., Fenton, 2006; Bridges, Bourke, et al, 2012; Silvestro et al, 2013; Banks et al, 2018; Cardinale et al, 2016; Runyon et al, 2017; Chojnacki et al, 2018; Chojnacki et al, 2019) and from landers and rovers on the Martian surface (e.g., Sullivan et al, 2008; Bridges & Ehlmann, 2018). Since 2006, the High Resolution Imaging Science Experiment (HiRISE) onboard the Mars Reconnaissance Orbiter has been imaging Mars at 0.25 m/pixel (McEwen et al, 2007); the acquisition of high‐resolution, DAVIS ET AL.

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