New Catalog of Thwaites Glacier Subglacial Lakes and Their Activity Revealed by CryoSat-2 Altimetry

Abstract

Previously, the existence of seven active subglacial lakes was reported beneath Thwaites Glacier, one of West Antarctica's largest glaciers, predicted to significantly impact future sea level rise. In this study, we re-evaluate the CryoSat-2 satellite radar altimeter data from 2010 to 2022 and identify 27 subglacial lakes that were active during 2013-2014 and 2016-2018, including those previously observed. Our new observations reveal three lakes located downstream of the lakes identified previously that appear to drain 3 months prior to the drainage of upstream lakes in 2013. Despite being over 100 km apart, the observed lakes (from the farthest upstream to downstream) exhibited synchronized behaviors. The timing of lake activities shows a complex activity propagation pattern, featuring both upward and downward transmission, contrasting with the simpler, one-directional flows observed in previous studies. While lake activities correlate with abrupt changes in ice speed near the grounding line, their impacts are limited, regardless of the total amount of drained water.