Convective vortex and dust devil predictions for Gale Crater over three Mars years and comparison with MSL‐REMS observations
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Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
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Date
2019-12
Major/Subject
Mcode
Degree programme
Language
en
Pages
3442-3468
Series
Journal of Geophysical Research: Planets, Volume 124, issue 12
Abstract
Convective vortices and dust devils have been inferred and observed in Gale Crater, Mars, using Mars Science Laboratory (MSL) meteorological data and camera images. Rennó et al. [1998] modeled convective vortices as convective heat engines and predicted a ‘dust devil activity' (DDA) that depends only on local meteorological variables, specifically the sensible heat flux and the vertical thermodynamic efficiency which increases with the pressure thickness of the planetary boundary layer. This work uses output from the MarsWRF General Circulation Model, run with high‐resolution nests over Gale Crater, to predict DDA as a function of location, time of day, and season, and compares these predictions to the record of vortices found in MSL's Rover Environmental Monitoring Station pressure dataset. Much of the observed time of day and seasonal variation of vortex activity is captured, such as maximum (minimum) activity in southern summer (winter), peaking between 11:00 and 14:00. However, while two daily peaks are predicted around both equinoxes, only a late morning peak is observed. An increase in vortex activity is predicted as MSL climbs the northwest slopes of Aeolis Mons, as observed. This is attributed largely to increased sensible heat flux, due to (i) larger daytime surface‐to‐air temperature differences over higher terrain, enhanced by reduced thermal inertia, and (ii) the increase in drag velocity associated with faster daytime upslope winds. However, the observed increase in number of vortex pressure drops is much stronger than the predicted DDA increase, although a better match exists when a threshold DDA is used.Description
Keywords
Mars, Convective vortices, Dust devils, Gale Crater, Mars Science Laboratory, Mars atmospheric modeling
Other note
Citation
Newman , C E , Kahanpää , H , Richardson , M I , Martinez , G , Vicente-Retortillo , Á & Lemmon , M 2019 , ' Convective vortex and dust devil predictions for Gale Crater over three Mars years and comparison with MSL‐REMS observations ' , Journal of Geophysical Research: Planets , vol. 124 , no. 12 , pp. 3442-3468 . https://doi.org/10.1029/2019JE006082
