Dr. Wang Yefan is an early carrier glaciologist, who is visiting Japan as a fellow of ArCS-3 Overseas Fellowship Program.<\/p>\n
Date: 17th September (Thus) 10:00-
\nVenue: Arctic Research Center, 1F meeting room
\nOnline link: https:\/\/meet.google.com\/gzo-dvuh-zjj
\nSpeaker\uff1aYefan Wang (University of Edinburgh, School of GeoSciences)
\nAbstract\uff1a
\nDynamic responses of Greenland lake-terminating glaciers to ice-marginal lake expansion and drainage
\nGlobal warming is driving significant mass loss from the Greenland Ice Sheet (GrIS), leading to extensive ice-margin retreat and increased meltwater runoff. Both processes have resulted in a widespread increase in the number, area, and volume of ice-marginal lakes around the GrIS. These lakes have the potential to accelerate ice motion through reduced basal friction and enhanced calving, thereby increasing mass loss from lake-terminating margins. However, their influence may vary substantially across spatial and temporal scales.
\nAt the Greenland-wide scale, analysis of 76 glaciers terminating in the 70 largest ice-marginal lakes between 1999 and 2024 reveals widespread retreat and thinning. Despite these geometric changes, 70% of the glaciers slowed rather than accelerated. This slowdown extended along the lowermost 10 km and was largely decoupled from retreat, thinning, and surface runoff. Near-terminus bed geometry partly modulated these responses, while inland overdeepenings suggest that continued retreat into deeper basins could increase future instability. As such, while lake expansion is not currently amplifying ice motion and dynamic mass loss, future glacier dynamics depend heavily on upglacier bed topography, which remains poorly constrained. At the individual glacier scale, ice dynamics can be abruptly perturbed by lake drainage events. At Isortuarsuup Sermia in southwest Greenland, multi-year acceleration was terminated by a high-magnitude lake drainage that reset the glacier to a quiescent state for several years. The 2022 event exemplifies this process, where near-terminus ice velocity accelerated from around 200 m\/yr to nearly 1000 m\/yr before dropping to 50 m\/yr over subsequent years. Each drainage releases an immense volume of meltwater and carves an efficient subglacial channel up to 1.5 km wide, causing an extensive drop in subglacial water pressure that increases basal friction and suppresses ice motion. As climate warming increases drainage frequency, this negative feedback may modulate ice-sheet discharge, effectively acting as a brake on margin dynamics.
\nTo examine whether this drainage-induced slowdown operates across different glaciological regimes, my ongoing stay at the NIPR focuses on two high-magnitude lake drainage events in north and northeast Greenland. Combining conventional satellite observations with ALOS-1\/2\/4 optical and L-band SAR data, we aim to resolve the detailed dynamic responses of these lake-terminating glaciers and clarify the mechanisms governing their stability.<\/p>","protected":false},"excerpt":{"rendered":"Dr. Wang Yefan is an early carrier glaciologist, who is visiting Japan as a fellow of ArCS-3 Overseas Fellowsh […]","protected":false},"author":4,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[24,35],"tags":[],"class_list":["post-11464","post","type-post","status-publish","format-standard","hentry","category-c-seminar","category-arcs3-news"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.arc.hokudai.ac.jp\/en\/wp-json\/wp\/v2\/posts\/11464","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.arc.hokudai.ac.jp\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.arc.hokudai.ac.jp\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.arc.hokudai.ac.jp\/en\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/www.arc.hokudai.ac.jp\/en\/wp-json\/wp\/v2\/comments?post=11464"}],"version-history":[{"count":2,"href":"https:\/\/www.arc.hokudai.ac.jp\/en\/wp-json\/wp\/v2\/posts\/11464\/revisions"}],"predecessor-version":[{"id":11467,"href":"https:\/\/www.arc.hokudai.ac.jp\/en\/wp-json\/wp\/v2\/posts\/11464\/revisions\/11467"}],"wp:attachment":[{"href":"https:\/\/www.arc.hokudai.ac.jp\/en\/wp-json\/wp\/v2\/media?parent=11464"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.arc.hokudai.ac.jp\/en\/wp-json\/wp\/v2\/categories?post=11464"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.arc.hokudai.ac.jp\/en\/wp-json\/wp\/v2\/tags?post=11464"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}