Characterization and formation of melt layers in polar snow : observations and experiments from West Antarctica
Characterization and formation of melt layers in polar snow : observations and experiments from West Antarctica
Date
2005
Authors
Das, Sarah B.
Alley, Richard B.
Alley, Richard B.
Linked Authors
Alternative Title
Citable URI
As Published
Date Created
Location
DOI
10.3189/172756505781829395
Related Materials
Replaces
Replaced By
Keywords
Abstract
Surface melting rarely occurs across most of the Antarctic ice sheet, away from the warmer
coastal regions. Nonetheless, isolated melt features are preserved in the firn and ice in response to
infrequent and short-lived melting events. An understanding of the formation and occurrence of these
melt layers will help us to interpret records of past melt occurrences from polar ice cores such as the
Siple Dome ice-core record from West Antarctica. A search in the near-surface firn in West Antarctica
found that melt features are extremely rare, and consist of horizontal, laterally continuous, one to a few
millimeter thick, ice layers with few air bubbles. The melt layers found date from the 1992/93 and
1991/92 summers. Field experiments to investigate changes in stratigraphy taking place during melt
events reproduced melt features as seen in the natural stratigraphy. Melting conditions of varying
intensity were created by passively heating the near-surface air for varying lengths of time inside a clear
plastic hotbox. Melt layers formed due entirely to preferential flow and subsequent refreezing of
meltwater from the surface into near-surface, fine-grained, crust layers. Continuous melt layers were
formed experimentally when positive-degree-day values exceeded 18C-day, a value corresponding well
with air-temperature records from automatic weather station sites where melt layers formed in the
recent past.
Description
Author Posting. © International Glaciological Society, 2005. This article is posted here by permission of International Glaciological Society for personal use, not for redistribution. The definitive version was published in Journal of Glaciology 51 (2005): 307-312, doi:10.3189/172756505781829395.
Embargo Date
Citation
Journal of Glaciology 51 (2005): 307-312