Seasonal evolution of supraglacial lake volume from aster imagery

Georgiou, S. and Shepherd, A. and Mcmillan, M. and Nienow, P. (2009) Seasonal evolution of supraglacial lake volume from aster imagery. Annals of Glaciology, 50 (52). pp. 95-100. ISSN 0260-3055

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Abstract

Water stored in and released from supraglacial lakes is an important factor when considering the seasonal and long-term evolution of the Greenland ice sheet. Here we use a radiative transfer model to estimate changes in the depth and volume of a supraglacial lake on the surface of Jakobshavn Isbræ, West Greenland, between 2002 and 2005. When compared to estimates of the lake depth determined from airborne lidar observations, we estimate that the root-mean-square departure of the modelled lake depths was 0.3 m during cloud-free conditions. The maximum lake area, depth and volume were 3.4 km 2, 9.6 ± 1.0 m and (18.6 ± 3.7) × 106 m3, respectively. When sequenced according to the number of positive degree-days (PDDs) accumulated prior to each image, we observe that the lake volume evolves in three distinct phases. At the start of the melting season, the rate of filling is slow; after approximately 80 PDDs the rate of filling increases by a factor ∼3, and after approximately 125 PDDs the lake drains rapidly. We estimate that the lake drains at a minimum rate of (2.66 ± 0.53) × 106 m3 d-1 over a 6 day period.

Item Type:
Journal Article
Journal or Publication Title:
Annals of Glaciology
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/1900/1904
Subjects:
ID Code:
128847
Deposited By:
Deposited On:
06 Nov 2018 09:24
Refereed?:
Yes
Published?:
Published
Last Modified:
07 Jan 2020 06:31