Trends in the Extent and Colour of Icelandic Proglacial Lakes Detected using Optical Satellite Remote Sensing

Abstract

Climate change has accelerated glacier melting in Iceland resulting in an increase in proglacial lakes. It is important to quantify these changes to characterise their evolution and understand environmental impacts. Proglacial lakes can enhance glacier ablation and store meltwater which can suddenly drain. In this thesis, I investigate drivers and trends in the extent and colour of Icelandic proglacial lakes. I determined a 34 year record of proglacial lake area at the terminus of Múlajökull from Landsat imagery. I then computed spatio-temporal variations in proglacial lake colour at 6 sites across Iceland using PlanetScope, Landsat and Sentinel satellites. Finally, I determined the concentration of suspended sediments in water samples collected from proglacial lakes in September and October 2024. My main research findings are that both the area and colour of Iceland’s proglacial lakes has changed over time. Between 1987 and 2021, proglacial lake area of Múlajökull increased from 0.16 ± 0.14 km2 to 1.27 ± 0.14 km2 as the terminus retreated by ~700 m. During this period, 40 % of 15 proglacial lakes studied became greener and 60 % became bluer. Finally, I deduce an empirical relationship between the colour of Icelandic proglacial lakes and the concentration of suspended sediment from satellite imagery. The work contained in my thesis matters because it expands the record of Icelandic proglacial lakes and increases our understanding of the factors that have driven change in their extent and colour over time. The observed increase in proglacial lake area and terminus retreat was driven by air temperature increase because of climate change. It is important to understand the changes in proglacial lake area as increases can further enhance glacier melt. Additionally, the change and variation in proglacial lake colour is caused by the concentration of sediment within each proglacial lake determined by glacial meltwater which can infer deglaciation.

Date of Award	19 Mar 2026
Original language	English
Awarding Institution	Northumbria University
Supervisor	Andrew Shepherd (Supervisor), Hilmar Gudmundsson (Supervisor), J. Rachel Carr (Supervisor) & Emily Hill (Supervisor)