Constraining 135 years of mass balance with historic structure-from-motion photogrammetry on Storglaciären, Sweden

Abstract

Geodetic volume estimates of Storglaciären in Sweden suggest a 28% loss in total ice mass between 1910 and 2015. Terrestrial photographs from 1910 of Tarfala valley, where Storglaciären is situated, allow for an accurate reconstruction of the glacier's surface using Structure-from-Motion photogrammetry, which we used for past volume and mass estimations. The glacier's yearly mass balance gradient and net mass balance was also estimated back to 1880 using weather data from Karesuando, 170 km northeast of Storglaciären, through neural network regression. These combined reconstructions provide a continuous mass change series between the end of the Little Ice Age and 1946, when field data become available. The resultant reconstruction suggests a state close to equilibrium between 1880 and the 1910s, followed by drastic melt until the 1970s, constituting 76% of the 1910-2015 ice loss. More favourable conditions subsequently stabilized the mass balance until the late 1990s, after which Storglaciären started losing mass again. The 1910 reconstruction allows for a more accurate mass change series than previous estimates, and the methodology can be used on other glaciers where early photographic material exists.

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

“…However, the mass balance recorded for Storglaciären, located in close proximity to Kebnepakte Glacier, was positive during eight out of the 35‐year timespan, 1910–1945 (Holmlund and Holmlund, ). It is reasonable to assume that similar climate conditions may have prevailed at Kebnepakte Glacier.…”

“…Changes in the surface elevation profiles of Kebnepakte Glacier since the time of its largest early 20 th century extent, which have not been reported in the literature previously, provide additional insight into the dynamic retreat of Kebnepakte Glacier since 1910, and can be compared to the behaviour of its neighbouring glacier Storglaciären (Holmlund and Holmlund, ).…”

“…The 1910 photographs by Enquist of Kebnepakte Glacier were processed in a reconstruction of the neighbouring Storglaciären (Holmlund and Holmlund, 2019). The reconstructed point cloud is shown in Fig.…”

“…10–15 m into the lake at the end of the 1990s (Fig. g), a period for which positive mass balance was documented for the neighbouring Storglaciären (Holmlund and Holmlund, ).…”

“…Kebnepakte Glacier, Sydöstra Kaskasatjåkkaglaciären, Sydvästra Kaskasatjåkkaglaciären and Sydöstra Kaskasapakteglaciären cover c. 25% of the lake catchment (c. 8.5 km 2 ). Kebnepakte Glacier has not been studied systematically, as opposed to other glaciers in the region, such as Storglaciären (Karlén, 1973;Holmlund and Holmlund, 2019). It is, however, known that Kebnepakte Glacier terminated in the northwestern part of Lake Tarfala until the mid-1940s.…”