Intra-surface radiative transfer limits the geographic extent of snow penitents on horizontal snowfields
Abstract:Penitents are broad snow spikes and ridges that range in height between centimeters and meters. Two key features of penitents remain unexplained: (1) they generally form at low latitudes and (2) their ridges and troughs have an east–west orientation. Here we show that surface-to-surface exchange of shortwave radiation and the local geometry of the sun's daily arc across the sky are the key processes that, in the absence of other effects, determine the geographic extent of where surface roughness features can grow or dissipate on snowfields and ice surfaces. As an application of our analysis, we examine the question of the geographic extent of snow penitents on horizontal surfaces. The results show that surface-to-surface radiative transfer can explain why penitents do not form on horizontal surfaces more than ∼55° off the equator. We further show on the basis of the sun's path across the sky that penitents that are corrugated, i.e. occur in long ridges or rows, must align their ridge axis within 30° of the east–west transect.
Document Type: Research Article
Publication date: February 1, 2014
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- The Journal of Glaciology is published six times per year. It accepts submissions from any discipline related to the study of snow and ice. All articles are peer reviewed. The Journal is included in the ISI Science Citation Index.
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