8898 Seminar Earth Sciences
Speaker: Tom Chudley
Seminar Title: Dynamic controls on the hydrology of the Greenland Ice Sheet
The Greenland Ice Sheet is the single largest contributor to global sea level rise, adding 7.5 mm to global mean sea level between 2006 and 2018. This mass loss has accelerated dramatically from near-balance in the 1990s due to two main processes: increased surface melt, and the discharge of ice from marine-terminating glaciers (i.e. iceberg calving). A key factor in determining the 21st-century impact of continued mass loss from the Greenland Ice Sheet will be the interaction between these two processes, as downstream impacts of meltwater routing can: (i) increase ice discharge to the ocean by lubricating the bed of the ice sheet and warming the ice column; (ii) drive ice retreat in fjords via submarine melt and ice calving from plumes; and (iii) alter fjord and ocean circulation and the biogeochemistry of key CO2 sinks. These impacts are controlled by the spatial and temporal distribution of meltwater pathways to the bed, but both the distribution and fundamental processes of meltwater delivery are very poorly implemented in current ice sheet models. Here, I discuss recent work in Greenland that aims to shed light on these processes, using a combination of ground-based geophysical measurements, uncrewed aerial vehicle (UAV) observations, and remote sensing techniques to explore interactions between ice hydrology and dynamics at high spatio-temporal resolutions. Presenting observations of supraglacial lakes, moulins, and ponded crevasses, I argue that ice dynamics (ice velocity, surface strain rate) are a key control on the spatial variability of meltwater drainage to the bed, particularly at marine-terminating sectors of the ice sheet where velocities are high and observations are sparse.
Host: Steven Lower
Zoom Meeting information
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