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| Titel |
Latitudinal variations in modeled insolation driven snow surface ablation |
| VerfasserIn |
L. M. Cathles, D. S. Abbot, D. R. MacAyeal |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250071628
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| Zusammenfassung |
| Net absorbed insolation is partially dependent on and positively correlated with surface
roughness, which changes through an ablation season. Understanding the feedback between
absorbed insolation and surface ablation is important for understanding the spatial and
temporal variations in surface ablation or melting. To investigate this feedback we
developed a numerical model to determine the absorption of insolation on an arbitrary
two-dimensional surface, and used the absorbed radiation to ablate that surface.
The model is used to investigate how surface topography evolves over an ablation
season. Results from numerical simulations reveal that the evolution of surface
features throughout an ablation season is strongly latitudinally dependent. At high
latitudes, the aspect ratio of surface features decreases through the ablation season,
reducing surface topography. At low latitudes, sinusoidal periodic surfaces grow in
amplitude as the surface ablates. This surface evolves into a series of peaks and valleys,
resembling penitentes, features observed in high alpine snow-packs in the tropics
and sub-tropics. Further investigation of the modeled latitudinal range at which
periodic surfaces grow in amplitude as well as their surface orientations matches
observational data on penitentes. In both high and low latitudes, topographic complexity
significantly increases the fraction of absorbed insolation relative to a flat surface. For
example, simulations for ablation in Greenland show that the inclusion of complex
features enhances absorption by 15 percent, or for a typical ablation season, 8 W m-2. |
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