Connected subglacial lake drainage beneath Thwaites Glacier, West Antarctica

• Published in: The Cryosphere
• Main Authors: Smith, Benjamin, Gourmelen, Noel, Huth, Alexander, Joughin, Ian
• Other Authors: School of Mathematics and statistics Sydney, The University of Sydney, Dynamique globale et déformation active (IPGS) (IPGS-DGDA), Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2017
• Subjects: [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph]; [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology; Thwaites Glacier; West Antarctica; Antarc*; Antarctica; The Cryosphere
• Online Access: https://hal.science/hal-01858777; https://hal.science/hal-01858777/document; https://hal.science/hal-01858777/file/tc-11-451-2017.pdf; https://doi.org/10.5194/tc-11-451-2017

International audience We present conventional and swath altimetry data from CryoSat-2, revealing a system of subglacial lakes that drained between June 2013 and January 2014 under the central part of Thwaites Glacier, West Antarctica (TWG). Much of the drainage happened in less than 6 months, with an apparent connection between three lakes spanning more than 130 km. Hydro-potential analysis of the glacier bed shows a large number of small closed basins that should trap water produced by subglacial melt, although the observed large-scale motion of water suggests that water can sometimes locally move against the apparent potential gradient, at least during lake-drainage events. This shows that there are important limitations in the ability of hydro-potential maps to predict subglacial water flow. An interpretation based on a map of the melt rate suggests that lake drainages of this type should take place every 20–80 years, depending on the connectivity of the water flow at the bed. Although we observed an acceleration in the downstream part of TWG immediately before the start of the lake drainage, there is no clear connection between the drainage and any speed change of the glacier.