1,2,3,4,2,5,6,6,7,1- 1Department of Environment and Geography, University of York, York, UK
- 2School of Geography, University of Leeds, Leeds, UK
- 3School of Earth and Environment, University of Leeds, Leeds, UK
- 4School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK
- 5School of Built Environment, Engineering and Computing, Leeds Beckett University, Leeds, UK
- 6Meteorology Department, University of Reading, Reading, UK
- 7School of Ocean Sciences, Bangor University, Bangor, UK
Large parts of the Greenland Ice Sheet are fringed by ice-marginal (or ice-contact) lakes. These lakes have increased in number and size as a result of enhanced ice melt and the retreat of the ice sheet margin over recent decades. It has historically been assumed that Greenlandic ice-marginal lakes exist at a relatively uniform temperature of around 1°C year-round, thus having minimal influence on ice dynamics and subaqueous melt rates at the ice-water interface. However, there are almost no in-situ temperature measurements to test this hypothesis, meaning their influence on future ice sheet behaviour remains unclear. Here, we present continuous time series of lake water temperatures collected between July 2024 and August 2025, within three lakes on the western margin of the Greenland Ice Sheet. The results show that lake surface temperatures reached highs exceeding 10°C, with water temperatures above 4°C throughout the entire water column of one study lake during summer months. Summer stratification often persisted for several weeks, whilst inverse stratification was observed when water temperatures fell below 4°C. During winter months, surface ice cover maintained stable inverse stratifications, with lake temperatures ranging between 0 and 4 °C. Although lake temperatures remained largely stable during winter, one lake exhibited a cooling trend and significantly higher variability, potentially indicative of continued subglacial meltwater input.
We combine our sub-hourly lake temperature measurements with meteorological, lake turbidity and ice front calving data, enabling us to investigate sub-diurnal to seasonal controls on lake temperature variability. These analyses show how neighbouring lakes can have markedly differing thermal characteristics, likely due to differences in size, localised topography and variable subglacial and supraglacial meltwater inputs. Our results highlight how uniformly cold temperature values are likely unsuitable when modelling ice-lake dynamics, and that lake terminating sectors of the ice sheet may be experiencing greater rates of frontal ablation than previously realised.
How to cite: Tuckett, P., Harpur, C., Scoffield, A., Quincey, D., Barnett, H., Abrahams, J., Mallalieu, J., Rawlins, L., Sutherland, J., Merchant, C., Woolway, R. I., Carrea, L., McCarroll, N., Wang, W., and Rippin, D.: Thermal characteristics of Greenlandic ice-marginal lakes derived from in-situ temperature data, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5028, https://doi.org/10.5194/egusphere-egu26-5028, 2026.
