Ice‐dammed lake drainage in west Greenland: Drainage pattern and implications on ice flow and bedrock motion. Issue 14 (18th July 2017)

• Record Type: Journal Article
• Authors: Kjeldsen, Kristian K.; Khan, Shfaqat A.; Bjørk, Anders A.; Nielsen, Karina; Mouginot, Jeremie
• Is Part Of: Geophysical research letters. Volume 44:Issue 14(2017)
• Page Start: 7320
• Page End: 7327
• Publication Date: 2017-07-18
• Subjects: Greenland -- ice‐dammed lake -- drainage pattern -- ice flow -- bedrock motion; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1002/2017GL074081
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: Ice‐dammed lakes drain frequently in Greenland, but the impacts of these events differ between sites. Here we study the quasi‐cyclic behavior of the ~40 km 2 Lake Tininnilik in west Greenland and its impact on ice flow and crustal deformation. Data reveal rapid drainage of 1.83 ± 0.17 km 3 of water in less than 7 days in 2010, leading to a speedup of the damming glacier, and an instantaneous modeled elastic bedrock uplift of 18.6 ± 0.1 mm confirmed by an independent lakeside GPS record. Since ice‐dammed lakes are common on Greenland, our results highlight the importance of including other sources of surface loading in addition to ice mass change, when assessing glacial isostatic adjustment or elastic rebound using geodetic data. Moreover, the results illustrates a linkage between subglacial discharge and ice surface velocity, important for assessing ice flux, and thus mass balance, in a future warming climate. Key Points: The period between drainage events has shortened from 10 to 5 years, coinciding with thinning of the damming glacier since the late 1990s Within 7 days, 1.83 ± 0.17 km 3 of water was released subglacially to a nearby fjord, leading to speedup of the damming glacier Rapid drainage caused 18.6 ± 0.1 mm of instantaneous elastic bedrock uplift in agreement with GPS data recorded adjacent to the lake