Measuring glacier mass changes from space—a review

Abstract

Glaciers distinct from the Greenland and Antarctic ice sheets are currently losing mass rapidly with direct and severe impacts on the habitability of some regions on Earth as glacier meltwater contributes to sea-level rise and alters regional water resources in arid regions. In this review, we present the different techniques developed during the last two decades to measure glacier mass change from space: digital elevation model differencing from stereo-imagery and synthetic aperture radar interferometry, laser and radar altimetry and space gravimetry. We illustrate their respective strengths and weaknesses to survey the mass change of a large Arctic ice body, the Vatnajökull Ice Cap (Iceland) and for the steep glaciers of the Everest area (Himalaya). For entire regions, mass change estimates sometimes disagree when a similar technique is applied by different research groups. At global scale, these discrepancies result in mass change estimates varying by 20 to 30%. Our review confirms the need for more thorough inter-comparison studies to understand the origin of these differences and to better constrain regional to global glacier mass changes and, ultimately, past and future glacier contribution to sea-level rise.

Exceptional thinning through the entire altitudinal range of Mont-Blanc glaciers during the 2021/22 mass balance year

“…Pléiades images are coded over 12 bits (4096 grey levels), compared to 8 bits only for older sensors such as ASTER. This ensures almost no saturation in snow-covered areas, strongly reducing the fraction of gaps in the DEMs (Berthier and others, 2023). We coregistered the DEMs on stable terrain, masking out glacierized areas using a glacier inventory from year 2015 (Paul and others, 2020).…”

“…), so the altitudinal extent of ice loss is yet to be fully established. We used here the digital elevation model (DEM) differencing method (Berthier and others, 2023) to document the influence of this exceptional year on the surface elevation of glaciers in the Mont-Blanc massif. We derived DEMs from Pléiades stereo-pairs acquired in 2012, 2021 and 2022 to observe the 9-yr and 1-yr glacier elevation changes and report on the altitudinal distribution of the exceptional thinning rates during the 2021/22 mass-balance year.…”

Remote Sensing and Modeling of the Cryosphere in High Mountain Asia: A Multidisciplinary Review

“…Satellite-based remote sensing techniques, specifically microwave and optical technologies, have been broadly applied in global-and regional-scale surveys of alpine glaciers due to the large number of glaciers and their relative remoteness [22,23]. By extension, the evolution and application of these technologies have been successfully adopted in HMA to measure glacier coverage, glacier area changes, glacier velocity/flow, glacier surging, and geodetic glacier mass balance.…”

“…The satellite-based geodetic glacier mass balance (MB) is primarily derived from surface elevation differencing (Supplementary Tables S1 and S3, Figure 3), i.e., between DEMs generated from photogrammetric images [58][59][60] or radar imagery, the bistatic differential SAR interferometry (DInSAR) [61], and satellite altimetry measurements, e.g., ICESat/GLAS [62], ICESat-2/ATLAS [63,64], and CryoSat-2 [23,65]. Recently, an albedo-MB approach was presented to evaluate glacier-wide surface annual MB change for large debris-free glacier areas [66,67].…”

Spatio-temporal variability in geometry and geodetic mass balance of Jostedalsbreen ice cap, Norway

“…While traditional photogrammetric processing requires significant manual operator input in aligning and georeferencing imagery, advances in automated photogrammetric pipelines such as structure from motion have made it possible to analyse historical and contemporary satellite and aerial datasets at extensive temporal and spatial scales (Mölg and Bolch, 2017). This has increased the availability of geodetic mass-balance records allowing glacier changes to be assessed in data-scarce regions, as well as analyses of glacier changes at continental to global scales (Hugonnet and others, 2021;Thompson and others, 2021;Berthier and others, 2023). Norway has extensive archives of historical aerial photography, which date back to the 1950s and 1960s in many regions, but most of that archive has not been utilised for assessing glacier changes.…”