Properties of natural supraglacial debris in relation to modelling sub-debris ice ablation

Auteur(s) et Affiliation(s)

NICHOLSON, L.

Centre for Climate and Cryosphere, Inst. for Meteorology and Geophysics, Univ., Innsbruck, Autriche

BENN, D.I.

Dep. of Arctic Geology, Univ. Centre in Svalbard, Longyearbyen, Norvege

School of Geography and Geosciences, Univ., St Andrews, Royaume-Uni

Description :
The AA. report measurements of vertical temperature profiles in debris on the Ngozumpa glacier in the Khumbu Himal region,Nepal, that show : 1) conductive processes dominate during the ablation season in matrix-supported diamict; 2) ventilation may be possible in coarse surface layers; 3) phase changes associated with seasonal change have a marked effect on the effective thermal diffusivity of the debris. Effective thermal conductivity determined from vertical temperature profiles in the debris is generally higher in summer than in winter, but values depend on the volume and phase of water in the debris. Surface albedo can vary widely over small spatial scales, as does the debris thickness. The findings from Ngozumpa glacier indicate that the probability distribution of debris thickness changes from positively skewed in the upper glacier towards a more normal distribution nearer the terminus. These observations highlight aspects of spatial and temporal variability in supraglacial debris that may require consideration in annual or multi-annual distributed modelling of debris-covered glacier surface energy and mass balance.

Type de document :
Article de périodique

Source :
Earth surface processes and landforms, issn : 0197-9337, 2013, vol. 38, n°. 5, p. 490-501, nombre de pages : 12, Références bibliographiques : 1 p.

Date :
2013

Editeur :
Pays édition : Royaume-Uni, Chichester, Wiley

Langue :
Anglais