High‐resolution bathymetric mapping reveals subaqueous glacial landforms in the Arctic alpine lake Tarfala, Sweden

Abstract

In Arctic alpine regions, glacio‐lacustrine environments respond sensitively to variations in climate conditions, impacting, for example,glacier extent and rendering former ice‐contact lakes into ice distal lakes and vice versa. Lakefloors may hold morphological records of past glacier extent, but remoteness and long periods of ice cover on such lakes make acquisition of high‐resolution bathymetric datasets challenging. Lake Tarfala and Kebnepakte Glacier, located in the Kebnekaise mountains, northern Sweden, comprise a small, dynamic glacio‐lacustrine system holding a climate archive that is not well studied. Using an autonomous surface vessel, a high‐resolution bathymetric dataset for Lake Tarfala was acquired in 2016, from which previously undiscovered end moraines and a potential grounding line feature were identified. For Kebnepakte Glacier, structure‐from‐motion photogrammetry was used to reconstruct its shape from photographs taken in 1910 and 1945. Combining these methods connects the glacial landform record identified at the lakefloor with the centennial‐scale dynamic behaviour of Kebnepakte Glacier. During its maximum 20th century extent, attained c. 1910, Kebnepakte Glacier reached far into Lake Tarfala, but had retreated onto land by 1945, at an average of 7.9 m year–1. Copyright © 2019 John Wiley & Sons, Ltd.

Submerged imprint of glacier dynamics in the NW sector of Lago Viedma (southern Patagonia, Argentina)

“…In addition, the deglaciation processes recorded in today's proglacial lakes are reflected in the sedimentary units below the lake floor. These units are generally associated with ice‐contact deposits, probably moraines and tills such as the 20th century moraines found in Lake Tarfala, Sweden (Kirchner et al, 2019) and of similar morphology to the deposits mapped on land by Allaart et al (2021) in Svalbard.…”

Lake Environmental Data Harvester (LED) for Alpine Lake Monitoring with Autonomous Surface Vehicles (ASVs)

“…The USVs were used in Plitvice Lakes National Park as a case study [39] for effective environmental monitoring. Surveys in remote lakes remain limited: geomorphological monitoring using drones in alpine lakes of Piedmont and FVG Regions [40]; joint LiDAR and echo sounding for Lake Truchillas Natural Monument's 3D profile with manned rafts [41]; Kapuche Lake's evolution and bathymetry via a sensored boat [42]; Tarfala (SE) glacial lake bathymetry with USVs transported by helicopters [43]; bed mapping at Mt. Zao Okama (JP) lake with low-quality, human-portable USVs [44]; and field experiments of an open-source, low-cost, small-sized USV in the USA and Peru [45].…”

A first continuous three-year temperature record from the dimictic arctic–alpine Lake Tarfala, northern Sweden

“…Lake Tarfala is a headwater lake in the Tarfala Valley in the Kebnekaise Mountains, northern Sweden (~67°55′ N, ~18°35′ E). Its surface area is ~0.56 km 2 , and its volume is 11.8 × 10 6 m 3 (Kirchner et al 2019). Lake Tarfala's catchment area is ~8.5 km 2 .…”

“…Pioneering investigations focusing on the bathymetry and thermal state of Lake Tarfala were made in 1959 and 1966/1967 (Larje and Nyberger 1960;Björklund 1967). For Lake Tarfala, the bathymetric information was updated recently to a modern, high-resolution data set (Kirchner et al 2019). Lake water temperature measurements have not been systematically repeated since 1966/1967.…”

“…In the Kebnekaise Mountains, northern Sweden, Lake Tarfala (Figure 1) is located in a proglacial alpine setting at 1,162 m.a.s.l. The Kebnepakte Glacier, neighboring Storglaciären for which the world's longest glacier mass balance record is kept, terminated with an ice cliff in Lake Tarfala until 1945 and retreated onto land thereafter (Kirchner et al 2019). With a maximum depth of 49.8 m, Lake Tarfala is exceptionally deep compared to other lakes at similar latitudes and/or altitudes, where mostly paleolimnological studies or short-term surveys of physical, biological, and chemical variables have been conducted (Anderson et al 1999;Massa et al 2012;Weckström et al 2016;Sharma et al 2019).…”