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UAV-based investigations into the hydrology and dynamics of the Greenland Ice Sheet 10.17863/CAM.58689 Chudley, Thomas 0000000185471132 Christoffersen, Poul Variation in the rate of meltwater input into the subglacial system of the Greenland Ice Sheet can force dynamic responses on a range of scales from hourly to interannual. Observations of the ice sheet dynamic response are commonly made either through ground-based Global Navigation Satellite System (GNSS) measurements, which can provide continuous and accurate point measurements, or through satellite remote sensing, which can provide regional-scale observations but at coarse temporal resolutions. This thesis investigates the potential of Uncrewed Aerial Vehicles (UAVs) to provide intermediate-level observations of the interactions between ice sheet hydrology and dynamics at a fast-flowing, marine terminating glacier in West Greenland. I first describe the development of a low- cost UAV suitable for deriving ice sheet velocity fields from Structure-from-Motion photogrammetry. In order to geolocate products without using ground control, image locations are determined directly using an on-board L1 GNSS receiver. I validate this method, showing that accuracies are sufficient for producing velocity fields in the ice sheet interior. Next, this method is used, alongside in-situ geophysical observations, to characterise the causes and dynamic influence of a rapid supraglacial lake drainage. I show that rapid drainage can induce a significant dynamic response up to 4 km away from the lake itself, and that fracture history can exert controls on interannual lake drainage behaviour. Finally, I upscale UAV ob- servations using satellite datasets over a ~3,000 km² area, exploring dynamic controls on crevasse hydrology. I find that in compressive mean stress compressive regimes, crevasses are more likely to display ponding and rapid hydrofracture than in extensional regimes, where continuous slow drainage is typical. Continued high-resolution observations are necessary to further identify key controls on the hydrological influences of Greenland Ice Sheet dynamics. University of Cambridge 2020-09-30 Thesis Doctoral Doctor of Philosophy (PhD) eng Funded by a Natural Environment Research Council studentship awarded through the Cambridge Earth System Science Doctoral Training Partnership (Grant NE/L002507/1). Research logistics funded by the European Research Council as part of the RESPONDER project under the European Union’s Horizon 2020 research and innovation program (Grant 683043). https://www.repository.cam.ac.uk/handle/1810/311597 https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/38048ef8-7737-4280-b055-f4de5a97b56f/download 4a5bd52d27a6aa8f0ff67de361e206f1 https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/fd135b53-b860-429d-a7b3-b563598ad96f/download 353adac0d1ebdfd65ab16480263c3c87 https://creativecommons.org/licenses/by/4.0/ glaciology ice sheet Greenland Ice Sheet Greenland Uncrewed Aerial Vehicle UAV remote sensing feature tracking GNSS GPS photogrammetry supraglacial hydrology supraglacial lake drainage crevasses crevasse hydrology ice dynamics hydrofracture Store Glacier Sermeq Kujalleq