Preprints
https://doi.org/10.5194/tc-2021-374
https://doi.org/10.5194/tc-2021-374

  10 Jan 2022

10 Jan 2022

Review status: this preprint is currently under review for the journal TC.

Filling and drainage of a subglacial lake beneath the Flade Isblink ice cap, northeast Greenland

Qi Liang1, Wanxin Xiao1, Ian Howat2,3, Xiao Cheng1, Fengming Hui1, Zhuoqi Chen1, Mi Jiang1, and Lei Zheng1 Qi Liang et al.
  • 1School of Geospatial Engineering and Science, Sun Yat-sen University & Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, Guangdong, China
  • 2Byrd Polar and Climate Research Center, Columbus, OH, USA
  • 3School of Earth Sciences, Ohio State University, Columbus, OH, USA

Abstract. The generation, transport, storage and drainage of meltwater beneath the ice sheet play important roles in the Greenland ice sheet (GrIS) system. Active subglacial lakes, common features in Antarctica, have recently been detected beneath GrIS and may impact ice sheet hydrology. Despite their potential importance, few repeat subglacial lake filling and drainage events have been identified under Greenland Ice Sheet. Here we examine the surface elevation change of a collapse basin at the Flade Isblink ice cap, northeast Greenland, which formed due to sudden subglacial lake drainage in 2011. We estimate the subglacial lake volume evolution using multi-temporal ArcticDEM data and ICESat-2 altimetry data acquired between 2012 and 2021. Our long-term observations show that the subglacial lake was continuously filled by surface meltwater, with basin surface rising by up to 55 m during 2012–2021 and we estimate 138.2 × 106 m3 of meltwater was transported into the subglacial lake between 2012 and 2017. A second rapid drainage event occurred in late August 2019, which induced an abrupt ice dynamic response. Comparison between the two drainage events shows that the 2019 drainage released much less water than the 2011 event. We conclude that multiple factors, e.g., the volume of water stored in the subglacial lake and bedrock relief, regulate the episodic filling and drainage of the lake. By comparing the surface meltwater production and the subglacial lake volume change, we find only ~64 % of the surface meltwater successfully descended to the bed, suggesting potential processes such as meltwater refreezing and firn aquifer storage, need to be further quantified.

Qi Liang et al.

Status: open (until 07 Mar 2022)

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Qi Liang et al.

Qi Liang et al.

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Short summary
Using multi-temporal ArcticDEM and ICESat-2 altimetry data, we document changes in surface elevation of a subglacial lake basin from 2012 to 2021. The long-term measurements show that the subglacial lake was recharged by surface meltwater and a rapid drainage event that occurred in late August 2019 induced an abrupt ice velocity change. Multiple factors regulate the episodic filling and drainage of the lake. Our study also reveals ~64 % of the surface meltwater successfully descended to the bed.