资源环境科技发展态势分析平台

Surge-type glaciers typically undergo cyclical flow instability due to mass accumulation; however, some recent glacier surges have caused irreversible ice loss in a short period. At Vavilov Ice Cap, Russia, surge-like behavior initiated in 2013 and by spring 2019 the ice cap had lost 9.5 Gt of ice (11% mass of the entire basin). Using time series of surface elevation and glacier velocity derived from satellite optical and synthetic-aperture radar imagery, we identify a shift of flow pattern starting in 2017 when shear margins formed within the grounded marine piedmont fan. Multiple summer speedups correlate with warmer summers during 2015-2019 and suggest that surface melt may access the subglacial environment. Force balance analysis and examination of the Peclet number show that glacier thinning propagated upstream in 2016-2017, and diffusion became a significant dynamic response to thinning perturbations. Our results suggest that the glacier has entered a new ice stream-like regime.