EGU21-1576, updated on 03 Mar 2021
https://doi.org/10.5194/egusphere-egu21-1576
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Lake Tarfala, N-Sweden – first results from a natural observatory mimicking future changes in glacier-fed Arctic lakes

Nina Kirchner1, Frederik Schenk2,6, Jakob Kuttenkeuler3, Gunhild Rosqvist1, Jan Weckström4, Kaarina Weckström4, Atte Korhola4, Marnie Hancke5, Annika Granebeck2, and Pia Eriksson1
Nina Kirchner et al.
  • 1Stockholm University, Bolin Centre for Climate Research, Department of Physical Geography, Stockholm, Sweden
  • 2Stockholm University, Bolin Centre for Climate Research, Department of Geological Sciences, Stockholm, Sweden
  • 3Department of Engineering Mechanics, Centre for Naval Architecture, KTH Royal Institute of Technology, 100 44 Stockholm, Sweden
  • 4Environmental Change Research Unit (ECRU), Faculty of Biological and Environmental Sciences and Helsinki Institute of Sustainability Science (HELSUS), University of Helsinki, 00014 Helsinki, Finland
  • 5Faculty of Natural Resources and Agricultural Sciences, Swedish University of Agricultural Sciences, 750 07 Uppsala, Sweden
  • 6Rossby Centre, Swedish Meteorological and Hydrological Institute, 601 76 Norrköping, Sweden

Lake Tarfala is an up to 50 m deep glacier-proximal Arctic lake in the Kebnekaise Mountains, northern Sweden (~67°55' N, ~18°35' E, 1162 m asl) in direct vicinity to the Tarfala Research Station run by Stockholm University, and to the glacier Storglaciären for which the world’s longest glacier mass balance record is kept since 1946. The neighboring Kebnepakte Glacier drains directly into Lake Tarfala. The site provides a unique an easily accessible natural observatory to study the impacts of climate and environmental change in an Arctic lake linked to a melting glacier.

As other Arctic lakes, Lake Tarfala is exposed to accelerated atmospheric warming in recent decades leading to increasingly shorter periods of lake freeze-over. Recent warming has also led to a widespread mass loss from glaciers with so for unclear implications for glacier-fed lakes which may receive larger amounts of meltwater and sediments from shrinking glaciers.

General atmospheric warming on the one hand and in response an increased influx of cold glacial meltwater to glacier-fed lakes on the other hand thus cause two competing processes determining the thermal state of a lake. Understanding (changing) lake thermal states and associated lake mixing dynamics is important because it has ramifications for a multitude of lake ecological, biological, and geochemical processes.

Here, we present the first continuous 3-year water temperature record from the deepest part of Lake Tarfala, acquired between 2016 and 2019. The record shows that Lake Tarfala is dimictic with overturning during spring and fall with substantial interannual variability concerning the timing, duration and intensity of mixing processes, as well as of summer and winter stratification. Particularly cold lake winter states appear to be related to elevated influx of cold glacial meltwater.

The projected high mass loss of Scandinavian glaciers with up to more than 80% of their volume under RCP8.5 until 2100 AD relative to 2015 renders Lake Tarfala a natural observatory where changes in processes, inherent timescales and impacts in response to competing drivers can be studied before they occur at other glacial lake sites where glaciers melt at a slower place.

How to cite: Kirchner, N., Schenk, F., Kuttenkeuler, J., Rosqvist, G., Weckström, J., Weckström, K., Korhola, A., Hancke, M., Granebeck, A., and Eriksson, P.: Lake Tarfala, N-Sweden – first results from a natural observatory mimicking future changes in glacier-fed Arctic lakes, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-1576, https://doi.org/10.5194/egusphere-egu21-1576, 2021.

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