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

Autor: Lemmon MT; Space Science Institute Boulder CO USA., Toledo D; Instituto Nacional de Técnica Aerospacial Madrid Spain., Apestigue V; Instituto Nacional de Técnica Aerospacial Madrid Spain., Arruego I; Instituto Nacional de Técnica Aerospacial Madrid Spain., Wolff MJ; Space Science Institute Boulder CO USA., Patel P; Jet Propulsion Laboratory California Institute of Technology Pasadena CA USA.; Mullard Space Science Laboratory University College London London UK., Guzewich S; NASA Goddard Space Flight Center Greenbelt MD USA., Colaprete A; NASA Ames Research Center Moffett Field CA USA., Vicente-Retortillo Á; Centro de Astrobiología (INTA-CSIC) Madrid Spain., Tamppari L; Jet Propulsion Laboratory California Institute of Technology Pasadena CA USA., Montmessin F; LATMOS Paris France., de la Torre Juarez M; Jet Propulsion Laboratory California Institute of Technology Pasadena CA USA., Maki J; Jet Propulsion Laboratory California Institute of Technology Pasadena CA USA., McConnochie T; Space Science Institute Boulder CO USA., Brown A; Plancius Research Severna Park MD USA., Bell JF 3rd; Arizona State University Tempe AZ USA.
Jazyk: angličtina
Zdroj: Geophysical research letters [Geophys Res Lett] 2022 Sep 16; Vol. 49 (17), pp. e2022GL099776. Date of Electronic Publication: 2022 Sep 09.
DOI: 10.1029/2022GL099776
Abstrakt: 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.
Competing Interests: The authors declare no conflicts of interest relevant to this study.
(© 2022. The Authors.)
Databáze: MEDLINE
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