Hexagonal Prisms Form in Water-Ice Clouds on Mars, Producing Halo Displays Seen by Perseverance Rover

M. T. Lemmon, D. Toledo, V. Apestigue, I. Arruego, M. J. Wolff, P. Patel, S. Guzewich, A. Colaprete, Vicente-Retortillo, L. Tamppari, F. Montmessin, M. de la Torre Juarez, J. Maki, T. McConnochie, A. Brown, J. F. Bell

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Observations by several cameras on the Perseverance rover showed a 22° scattering halo around the Sun over several hours during northern midsummer (solar longitude 142°). Such a halo has not previously been seen beyond Earth. The halo occurred during the aphelion cloud belt season and the cloudiest time yet observed from the Perseverance site. The halo required crystalline water-ice cloud particles in the form of hexagonal columns large enough for refraction to be significant, at least 11 μm in diameter and length. From a possible 40–50 km altitude, and over the 3.3 hr duration of the halo, particles could have fallen 3–12 km, causing downward transport of water and dust. Halo-forming clouds are likely rare due to the high supersaturation of water that is required but may be more common in northern subtropical regions during northern midsummer.

Original languageEnglish (US)
Article numbere2022GL099776
JournalGeophysical Research Letters
Volume49
Issue number17
DOIs
StatePublished - Sep 16 2022
Externally publishedYes

ASJC Scopus subject areas

  • Geophysics
  • Earth and Planetary Sciences(all)

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