High-resolution inventory to capture glacier disintegration in the Austrian Silvretta

Abstract

Abstract. A new high-resolution glacier inventory captures the rapid decay of the glaciers in the Austrian Silvretta for the years 2017 and 2018. Identifying the glacier outlines offers a wide range of possible interpretations of glaciers that have evolved into small and now totally debris-covered cryogenic structures. In previous inventories, a high proportion of active bare ice allowed a clear delineation of the glacier margins even by optical imagery. In contrast, in the current state of the glacier only the patterns and amounts of volume change allow us to estimate the area of the buried glacier remnants. We mapped the glacier outlines manually based on lidar elevation models and patterns of volume change at 1 to 0.5 m spatial resolution. The vertical accuracy of the digital elevation models (DEMs) generated from six to eight lidar points per square metre is of the order of centimetres. Between 2004/2006 and 2017/2018, the 46 glaciers of the Austrian Silvretta lost −29 ± 4 % of their area and now cover 13.1 ± 0.4 km2. This is only 32 ± 2 % of their Little Ice Age (LIA) extent of 40.9 ± 4.1 km2. The area change rate increased from 0.6 %/yr (1969–2002) to −2.4 %/yr (2004/2006–2017/2018). The Sentinel-2-based glacier inventory of 2018 deviates by just 1 % of the area. The annual geodetic mass balance referring to the area at the beginning of the period showed a loss increasing from −0.2 ± 0.1 m w.e./yr (1969–2002) to −0.8 ± 0.1 m w.e./yr (2004/2006–2017/2018) with an interim peak in 2002–2004/2006 of −1.5 ± 0.7 m w.e./yr. To keep track of the buried ice and its fate and to distinguish increasing debris cover from ice loss, we recommend inventory repeat frequencies of 3 to 5 years and surface elevation data with a spatial resolution of 1 m.

Combination of historical and modern data to decipher the geomorphic evolution of the Innere Ölgruben rock glacier, Kaunertal, Austria, over almost a century (1922–2021)

“…The glacier evolution was primarily reconstructed to assess the approximate glacier extent at the end of the LIA and to be able to depict the glacier development in the catchments of the two lobes during the study period (Figure 1). Abermann et al 67 have highlighted the potential of high‐resolution DEMs to mapping glacier outlines, which has been adopted by several studies on individual glaciers (e.g., Klug et al 68 ) or entire mountain ranges (e.g., Fischer et al 69 ). Following this published approach, we utilize DEMs (and their derivatives) derived from ALS data (2017 and 2006: Office of the Tyrolean Government, Department of Geoinformation/Tyrol, Austria; 2012: PROSA [PROglacial Systems of the Alps] project) and photogrammetric techniques (1953 and 1970: aerial photographs; see Section 2.2).…”

Contemporary mass balance on a cold Eastern Alpine ice cap as a potential link to the Holocene climate

“…For the DEM of 2006, the uncertainty is ± 0.1 m 56 . The standard deviation at control areas for the DEM of 2018 was 0.032 m 57 . The effects of a seasonal snow cover, to be added to the nominal accuracy of the DEMs, can be estimated by the maximum snow cover recorded at the AWS to be about 2 m.…”

Moraines in the Austrian Alps record repeated phases of glacier stabilization through the Late Glacial and the Early Holocene

“…This study extends the Jamtal glacier chronology into the LG and focuses on landforms that evidence glacier oscillations during this period by mapping and dating ice margins outboard the Holocene moraines. Reconstructions of paleoglaciers are complemented with glaciological data of modern, annual- to decadal-scale glacier change, including observations of glacier mass balances, front variation, and ice-covered area 14 , 20 , 93 , 94 .…”

“…1250–1850 CE) in the reference years 2017/2018 (Fig. 1 b) 14 . Jamtal glacier—the main ice body at Jamtal—has retreated to a position ca.…”