 |
| Titel |
Meteorological drivers of ablation processes on a cold glacier in the semi-arid Andes of Chile |
| VerfasserIn |
S. MacDonell, C. Kinnard, T. Mölg, L. Nicholson, J. Abermann |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1994-0416
|
| Digitales Dokument |
URL |
| Erschienen |
In: The Cryosphere ; 7, no. 5 ; Nr. 7, no. 5 (2013-09-25), S.1513-1526 |
| Datensatznummer |
250085164
|
| Publikation (Nr.) |
 copernicus.org/tc-7-1513-2013.pdf |
|
|
|
|
|
| Zusammenfassung |
| 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), shortwave radiation receipt persistently close to the
theoretical site maximum during cloud-free days (mean annual
295 W m−2; summer hourly maximum 1354 W m−2) and low
precipitation rates (mean annual 45 mm w.e.). Snowfall occurs sporadically
throughout the year and is related to frontal events in the winter and
convective storms during the summer months. 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. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|