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Snow spikes (penitentes) in the dry Andes, but not on Europa: a defense of Lliboutry's classic paper

Authors :
Stephen G. Warren
Source :
Annals of Glaciology, Vol 63, Pp 62-66 (2022)
Publication Year :
2022
Publisher :
Cambridge University Press, 2022.

Abstract

Tall, spiky snow structures (penitentes) occur high in subtropical mountains, in the form of blades oriented east-west and tilted toward the noontime sun. By trapping sunlight, they cause a reduction of albedo by ~0.3 relative to flat snow. The formation of penitentes, explained by Lliboutry in 1954, requires weather conditions allowing the troughs to deepen rapidly by melting while the peaks remain dry and cold by sublimation, losing little mass, because of the 8.5-fold difference in latent heats. Lliboutry's explanation has been misrepresented in some recent publications. A concern has been raised that in the low latitudes of Jupiter's moon Europa, the ice surface may have developed penitentes, which would pose a hazard to a lander. They would require a different mechanism of formation, because Europa is too cold for melting to occur. If penitentes are present on Europa, they cannot be resolved by the coarse-resolution satellite images available now, but the high albedo of Europa (~0.7 at visible wavelengths) argues against the existence of such extreme roughness.

Details

Language :
English
ISSN :
02603055 and 17275644
Volume :
63
Database :
Directory of Open Access Journals
Journal :
Annals of Glaciology
Publication Type :
Academic Journal
Accession number :
edsdoj.4ef551591fa04a639e66579cc2616a3f
Document Type :
article
Full Text :
https://doi.org/10.1017/aog.2023.12