Observational evidence of a suppressed planetary boundary layer in northern Gale Crater, Mars as seen by the Navcam instrument onboard the Mars Science Laboratory rover

John E. Moores, Mark T. Lemmon, Henrik Kahanpää, Scot C. R. Rafkin, Raymond Francis, Jorge Pla-Garcia, Keri Bean, Robert Haberle, Claire Newman, Michael Mischna, Ashwin R. Vasavada, Manuel de la Torre Juárez, Nilton Rennó, Jim Bell, Fred Calef, Bruce Cantor, Timothy H. Mcconnochie, Ari-Matti Harri, Maria Genzer, Michael H. WongMichael D. Smith, F. Javier Martín-Torres, María-Paz Zorzano, Osku Kemppinen, Emily McCullough

Research output: Contribution to journalArticle

44 Citations (Scopus)

Abstract

The Navigation Cameras (Navcam) of the Mars Science Laboratory rover, Curiosity, have been used to examine two aspects of the planetary boundary layer: vertical dust distribution and dust devil frequency. The vertical distribution of dust may be obtained by using observations of the distant crater rim to derive a line-of-sight optical depth within Gale Crater and comparing this optical depth to column optical depths obtained using Mastcam observations of the solar disc. The line of sight method consistently produces lower extinctions within the crater compared to the bulk atmosphere. This suggests a relatively stable atmosphere in which dust may settle out leaving the air within the crater clearer than air above and explains the correlation in observed column opacity between the floor of Gale Crater and the higher elevation Meridiani Planum. In the case of dust devils, despite an extensive campaign only one optically thick vortex (τ = 1.5 ± 0.5 × 10-3) was observed compared to 149 pressure events >0.5 Pa observed in REMS pressure data. Correcting for temporal coverage by REMS and geographic coverage by Navcam still suggests 104 vortices should have been viewable, suggesting that most vortices are dustless. Additionally, the most intense pressure excursions observed on other landing sites (pressure drop >2.5 Pa) are lacking from the observations by the REMS instrument. Taken together, these observations are consistent with pre-landing circulation modeling of the crater showing a suppressed, shallow boundary layer. They are further consistent with geological observations of dust that suggests the northern portion of the crater is a sink for dust in the current era.

Original languageEnglish
Pages (from-to)129-142
Number of pages14
JournalIcarus (New York, N.Y. 1962)
Volume249
Early online date30 Sep 2014
DOIs
Publication statusPublished - 15 Mar 2015

Keywords

  • Mars
  • atmosphere
  • Atmospheres
  • dynamics
  • structure

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    Moores, J. E., Lemmon, M. T., Kahanpää, H., Rafkin, S. C. R., Francis, R., Pla-Garcia, J., Bean, K., Haberle, R., Newman, C., Mischna, M., Vasavada, A. R., de la Torre Juárez, M., Rennó, N., Bell, J., Calef, F., Cantor, B., Mcconnochie, T. H., Harri, A-M., Genzer, M., ... McCullough, E. (2015). Observational evidence of a suppressed planetary boundary layer in northern Gale Crater, Mars as seen by the Navcam instrument onboard the Mars Science Laboratory rover. Icarus (New York, N.Y. 1962), 249, 129-142. https://doi.org/10.1016/j.icarus.2014.09.020