Large interannual variability in supraglacial lakes around East Antarctica

Antarctic supraglacial lakes (SGLs) have been linked to ice shelf collapse and the subsequent acceleration of inland ice flow. These processes are difficult to capture in numerical ice sheet models, but those that include them project higher sea-level contributions from Antarctica. However, observations of SGLs in Antarctica remain relatively scarce and their seasonal variability is largely unknown, making it difficult to assess whether some ice shelves are close to thresholds of stability under climate warming. Here, we quantify the variability in SGL distributions and volumes across the entire East Antarctic Ice Sheet around the peak of seven consecutive melt seasons (2014-2020). We investigate potential climatic controls on SGL development and near-surface (i.e. firn) conditions generated by ERA5 climate reanalysis and the Community Firn Model forced by the regional climate model MARv3.11. Interannual variability in SGL volume is >200% on some ice shelves, but patterns are highly asynchronous. More extensive, deeper SGLs correlate with higher summer (December-January-February) air temperatures, but comparisons with modelled melt and runoff are complex. However, we find that modelled January melt and the ratio of November firn air content to summer melt are important predictors of SGL volume on some potentially vulnerable ice shelves, suggesting large increases in SGLs should be expected under future atmospheric warming.