The Cryosphere Discuss., 7, 1833-1870, 2013
www.the-cryosphere-discuss.net/7/1833/2013/
doi:10.5194/tcd-7-1833-2013
© Author(s) 2013. This work is distributed
under the Creative Commons Attribution 3.0 License.
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This discussion paper has been under review for the journal The Cryosphere (TC). Please refer to the corresponding final paper in TC.
Meteorological drivers of ablation processes on a cold glacier in the semiarid Andes of Chile
S. MacDonell1, C. Kinnard1, T. Mölg2, L. Nicholson3, and J. Abermann1
1Centro de Estudios Avanzados en Zonas Áridas, La Serena, Chile
2Chair of Climatology, Technische Universität Berlin, Berlin, Germany
3Centre for Climate and Cryosphere, University of Innsbruck, Innsbruck, Austria

Abstract. Meteorological and surface change measurements collected during a 2.5 yr period are used to calculate surface mass and energy balances at 5324 m a.s.l. on Guanaco Glacier, a cold-based glacier in the semi-arid Andes of Chile. Meteorological conditions are marked by extremely low vapour pressures (annual mean of 1.1 hPa), strong winds (annual mean of 10 m s−1), high shortwave radiation receipt (mean annual 295 W m−2) and low precipitation rates (mean annual 45 mm w.e.). Net shortwave radiation provides the greatest source of energy to the glacier surface, and net longwave radiation dominates energy losses. The turbulent latent heat flux is always negative, which means that the surface is always losing mass via sublimation, which is the main form of ablation at the site. Sublimation rates are most strongly correlated with net shortwave radiation, incoming shortwave radiation, albedo and vapour pressure. Low glacier surface temperatures restrict melting for much of the period, however episodic melting occurs during the austral summer, when warm, humid, calm and high pressure conditions restrict sublimation and make more energy available for melting. Low accumulation (131 mm w.e. over the period) and relatively high ablation (1435 mm w.e.) means that mass change over the period was negative (−1304 mm w.e.), which continued the negative trend recorded in the region over the last few decades.

Citation: MacDonell, S., Kinnard, C., Mölg, T., Nicholson, L., and Abermann, J.: Meteorological drivers of ablation processes on a cold glacier in the semiarid Andes of Chile, The Cryosphere Discuss., 7, 1833-1870, doi:10.5194/tcd-7-1833-2013, 2013.
 
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