Naomi Ochwat

The Antarctic Peninsula (AP), encompassing the ice sheet and its peripheral glaciers, is a highly dynamic component of the cryosphere that disproportionately contributes to sea-level rise relative to its size. However, a large spread remains between the mass changes estimated using gravimetry, altimetry and the mass budget method. Among these techniques, the satellite (radar or laser) altimetry method has a resolution of, at best, 1 km, which is too coarse to resolve the mountainous landscape of the Peninsula. Therefore, we use digital elevation models (DEMs; 30 × 30 m) to provide an estimate of mass changes across the AP between 2007 and 2021. We combine 476 DEMs derived from SPOT5-HRS satellite images (2006–2008) and 2525 DEMs of the Reference Elevation Model of Antarctica (2020–2022) to map elevation changes for the entire Peninsula. We vertically adjusted each DEM using near-coincident ICESat/-2 laser altimetry measurements. Our observations cover 70 % of the AP Ice Sheet and 60 % of its peripheral glaciers, including regions of the Peninsula poorly studied to date, and reveal a spatially complex pattern of elevation changes. After correction with different models of firn air content and solid-earth response, we find that between 2007 and 2021, the AP Ice Sheet lost 28 ± 6 Gt a⁻¹ while its peripheral glaciers lost 14 ± 3 Gt a⁻¹. For the AP Ice Sheet, our new estimate is 4 to 5 times more negative than the one obtained in IMBIE using altimetry data (−5.2 ± 1.8 Gt a⁻¹ from 2007 to 2019) and in better agreement with gravimetry and the mass budget method. Our study highlights the importance of resolving fine scale elevation changes of glaciers and ice sheets in complex, dynamic coastal areas.

The Antarctic Peninsula (AP), encompassing the ice sheet and its peripheral glaciers, is a highly dynamic component of the cryosphere that disproportionately contributes to sea level rise relative to its size. However, a large spread remains between the mass changes estimated using gravimetry, altimetry and the mass budget method. Among these techniques, the satellite (radar or laser) altimetry method has a resolution of, at best, 1 km, which is coarse to resolve the mountainous landscape of the Peninsula. Therefore, we use digital elevation models (DEMs; 30 x 30 m) to provide an estimate of mass changes across the AP between 2007 and 2021. We combine 476 DEMs derived from SPOT5-HRS satellite images (2006–2008) and 2 525 DEMs of the Reference Elevation Model of Antarctica (2020–2022) to map elevation changes for the entire Peninsula. We vertically adjusted each DEM using near-coincident ICESat/-2 laser altimetry measurements. Our observations cover 70 % of the AP Ice Sheet and 60 % of its peripheral glaciers, including regions of the Peninsula poorly studied to date, and reveal a spatially complex pattern of elevation changes. After correction with different models of firn air content and solid-earth response, we find that between 2007 and 2021, the AP Ice Sheet lost -27 ± 9 Gt/a while its peripheral glaciers lost -14 ± 2 Gt/a. For the AP Ice Sheet, our new estimate is four to five times more negative than the one obtained in IMBIE using altimetry data (-5.2 ± 2.3 Gt/a from 2007 to 2019) and in better agreement with gravimetry and the mass budget method. Our study highlights the importance of resolving fine scale elevation changes of glaciers and ice sheets in complex, dynamic coastal areas.

The Antarctic Peninsula (AP), encompassing the ice sheet and its peripheral glaciers, is a highly dynamic component of the cryosphere that disproportionately contributes to sea level rise relative to its size. However, a large spread remains between the mass changes estimated using gravimetry, altimetry and the mass budget method. Among these techniques, the satellite (radar or laser) altimetry method has a resolution of, at best, 1 km, which is coarse to resolve the mountainous landscape of the Peninsula. Therefore, we use digital elevation models (DEMs; 30 x 30 m) to provide an estimate of mass changes across the AP between 2007 and 2021. We combine 476 DEMs derived from SPOT5-HRS satellite images (2006–2008) and 2 525 DEMs of the Reference Elevation Model of Antarctica (2020–2022) to map elevation changes for the entire Peninsula. We vertically adjusted each DEM using near-coincident ICESat/-2 laser altimetry measurements. Our observations cover 70 % of the AP Ice Sheet and 60 % of its peripheral glaciers, including regions of the Peninsula poorly studied to date, and reveal a spatially complex pattern of elevation changes. After correction with different models of firn air content and solid-earth response, we find that between 2007 and 2021, the AP Ice Sheet lost -27 ± 9 Gt/a while its peripheral glaciers lost -14 ± 2 Gt/a. For the AP Ice Sheet, our new estimate is four to five times more negative than the one obtained in IMBIE using altimetry data (-5.2 ± 2.3 Gt/a from 2007 to 2019) and in better agreement with gravimetry and the mass budget method. Our study highlights the importance of resolving fine scale elevation changes of glaciers and ice sheets in complex, dynamic coastal areas.

The Antarctic Peninsula (AP), encompassing the ice sheet and its peripheral glaciers, is a highly dynamic component of the cryosphere that disproportionately contributes to sea level rise relative to its size. However, a large spread remains between the mass changes estimated using gravimetry, altimetry and the mass budget method. Among these techniques, the satellite (radar or laser) altimetry method has a resolution of, at best, 1 km, which is coarse to resolve the mountainous landscape of the Peninsula. Therefore, we use digital elevation models (DEMs; 30 x 30 m) to provide an estimate of mass changes across the AP between 2007 and 2021. We combine 476 DEMs derived from SPOT5-HRS satellite images (2006–2008) and 2 525 DEMs of the Reference Elevation Model of Antarctica (2020–2022) to map elevation changes for the entire Peninsula. We vertically adjusted each DEM using near-coincident ICESat/-2 laser altimetry measurements. Our observations cover 70 % of the AP Ice Sheet and 60 % of its peripheral glaciers, including regions of the Peninsula poorly studied to date, and reveal a spatially complex pattern of elevation changes. After correction with different models of firn air content and solid-earth response, we find that between 2007 and 2021, the AP Ice Sheet lost -27 ± 9 Gt/a while its peripheral glaciers lost -14 ± 2 Gt/a. For the AP Ice Sheet, our new estimate is four to five times more negative than the one obtained in IMBIE using altimetry data (-5.2 ± 2.3 Gt/a from 2007 to 2019) and in better agreement with gravimetry and the mass budget method. Our study highlights the importance of resolving fine scale elevation changes of glaciers and ice sheets in complex, dynamic coastal areas.

The Antarctic Peninsula (AP), encompassing the ice sheet and its peripheral glaciers, is a highly dynamic component of the cryosphere that disproportionately contributes to sea level rise relative to its size. However, a large spread remains between the mass changes estimated using gravimetry, altimetry and the mass budget method. Among these techniques, the satellite (radar or laser) altimetry method has a resolution of, at best, 1 km, which is coarse to resolve the mountainous landscape of the Peninsula. Therefore, we use digital elevation models (DEMs; 30 x 30 m) to provide an estimate of mass changes across the AP between 2007 and 2021. We combine 476 DEMs derived from SPOT5-HRS satellite images (2006–2008) and 2 525 DEMs of the Reference Elevation Model of Antarctica (2020–2022) to map elevation changes for the entire Peninsula. We vertically adjusted each DEM using near-coincident ICESat/-2 laser altimetry measurements. Our observations cover 70 % of the AP Ice Sheet and 60 % of its peripheral glaciers, including regions of the Peninsula poorly studied to date, and reveal a spatially complex pattern of elevation changes. After correction with different models of firn air content and solid-earth response, we find that between 2007 and 2021, the AP Ice Sheet lost -27 ± 9 Gt/a while its peripheral glaciers lost -14 ± 2 Gt/a. For the AP Ice Sheet, our new estimate is four to five times more negative than the one obtained in IMBIE using altimetry data (-5.2 ± 2.3 Gt/a from 2007 to 2019) and in better agreement with gravimetry and the mass budget method. Our study highlights the importance of resolving fine scale elevation changes of glaciers and ice sheets in complex, dynamic coastal areas.

The Antarctic Peninsula (AP), encompassing the ice sheet and its peripheral glaciers, is a highly dynamic component of the cryosphere that disproportionately contributes to sea level rise relative to its size. However, a large spread remains between the mass changes estimated using gravimetry, altimetry and the mass budget method. Among these techniques, the satellite (radar or laser) altimetry method has a resolution of, at best, 1 km, which is coarse to resolve the mountainous landscape of the Peninsula. Therefore, we use digital elevation models (DEMs; 30 x 30 m) to provide an estimate of mass changes across the AP between 2007 and 2021. We combine 476 DEMs derived from SPOT5-HRS satellite images (2006–2008) and 2 525 DEMs of the Reference Elevation Model of Antarctica (2020–2022) to map elevation changes for the entire Peninsula. We vertically adjusted each DEM using near-coincident ICESat/-2 laser altimetry measurements. Our observations cover 70 % of the AP Ice Sheet and 60 % of its peripheral glaciers, including regions of the Peninsula poorly studied to date, and reveal a spatially complex pattern of elevation changes. After correction with different models of firn air content and solid-earth response, we find that between 2007 and 2021, the AP Ice Sheet lost -27 ± 9 Gt/a while its peripheral glaciers lost -14 ± 2 Gt/a. For the AP Ice Sheet, our new estimate is four to five times more negative than the one obtained in IMBIE using altimetry data (-5.2 ± 2.3 Gt/a from 2007 to 2019) and in better agreement with gravimetry and the mass budget method. Our study highlights the importance of resolving fine scale elevation changes of glaciers and ice sheets in complex, dynamic coastal areas.

The Antarctic Peninsula (AP), encompassing the ice sheet and its peripheral glaciers, is a highly dynamic component of the cryosphere that disproportionately contributes to sea level rise relative to its size. However, a large spread remains between the mass changes estimated using gravimetry, altimetry and the mass budget method. Among these techniques, the satellite (radar or laser) altimetry method has a resolution of, at best, 1 km, which is coarse to resolve the mountainous landscape of the Peninsula. Therefore, we use digital elevation models (DEMs; 30 x 30 m) to provide an estimate of mass changes across the AP between 2007 and 2021. We combine 476 DEMs derived from SPOT5-HRS satellite images (2006–2008) and 2 525 DEMs of the Reference Elevation Model of Antarctica (2020–2022) to map elevation changes for the entire Peninsula. We vertically adjusted each DEM using near-coincident ICESat/-2 laser altimetry measurements. Our observations cover 70 % of the AP Ice Sheet and 60 % of its peripheral glaciers, including regions of the Peninsula poorly studied to date, and reveal a spatially complex pattern of elevation changes. After correction with different models of firn air content and solid-earth response, we find that between 2007 and 2021, the AP Ice Sheet lost -27 ± 9 Gt/a while its peripheral glaciers lost -14 ± 2 Gt/a. For the AP Ice Sheet, our new estimate is four to five times more negative than the one obtained in IMBIE using altimetry data (-5.2 ± 2.3 Gt/a from 2007 to 2019) and in better agreement with gravimetry and the mass budget method. Our study highlights the importance of resolving fine scale elevation changes of glaciers and ice sheets in complex, dynamic coastal areas.

The Antarctic Peninsula (AP), encompassing the ice sheet and its peripheral glaciers, is a highly dynamic component of the cryosphere, disproportionately contributing to sea level rise. However, a large spread remains between the mass changes estimated using gravimetry, altimetry and the input/output method. Among these techniques, the satellite (radar or laser) altimetry method has a resolution of, at best, 1 km, which is too coarse to resolve the complex pattern of changes in the Peninsula. Therefore, we use digital elevation models (DEMs; 30x30 m) to map elevation changes for the entire Peninsula, combining 476 DEMs derived from SPOT5-HRS satellite images (2006-2008) and 2525 strips of the Reference Elevation Model of Antarctica (2020-2022) to provide a comprehensive 14-year record. We bias-corrected each DEM using near-synchronous ICESat/-2 laser altimetry measurements.Our observations cover 70% of the AP ice sheet and 60% of its peripheral glaciers, including for regions of the Peninsula poorly studied to date and decipher a spatially complex pattern of elevation changes. After correction with different models of firn air content and solid-earth response, we find that between 2007 and 2021, the AP ice sheet lost -27 ± 9 Gt/yr while its peripheral glaciers lost -14 ± 2 Gt/yr. For the AP ice sheet, our new estimate is 4 to 5 times more negative than the one obtained in IMBIE using purely altimetry data (-6 ± 6 Gt/yr from 2006 to 2018) and in better agreement with gravimetry and the input/output method. Our study highlights the importance of resolving fine scale elevation changes of glaciers and ice sheets.

Wave ogives are among the most striking and least studied glacier surface features. They sometimes form at the bottom of icefalls, yet exactly how they form has eluded scientists for decades. On the Gilkey Glacier, below the Vaughan Lewis Icefall in the Juneau Icefield region of Alaska there is a well-developed series of wave ogives. Our study uses geophysical field observations of the Gilkey Glacier ogives combined with satellite data and modeling to better understand the formation process. Satellite-derived DEMs provide ogive amplitudes of 5-8 m and wavelengths of ~130 m. By combining Global Navigation Satellite System (GNSS), satellite, and timelapse camera-derived velocity observations, we found that the Vaughan Lewis Glacier is significantly slower than the Gilkey Glacier (60 m/yr compared to 130 m/yr), and the icefall is exceptionally fast (~2200 m/yr). We used the velocity and ogive characteristics to constrain parameters in a finite-difference numerical model that simulates ogive formation. Using this model, we tested the plausibility of the two formation mechanisms; i) seasonal mass balance variation; and ii) seasonal velocity variation of the lower glacier. Our results suggest that seasonal velocity variation of the lower glacier is the primary driver in wave ogive formation.

The Antarctic Peninsula (AP), encompassing the ice sheet and its peripheral glaciers, is a highly dynamic component of the cryosphere that disproportionately contributes to sea level rise relative to its size. However, a large spread remains between the mass changes estimated using gravimetry, altimetry and the mass budget method. Among these techniques, the satellite (radar or laser) altimetry method has a resolution of, at best, 1 km, which is coarse to resolve the mountainous landscape of the Peninsula. Therefore, we use digital elevation models (DEMs; 30 x 30 m) to provide an estimate of mass changes across the AP between 2007 and 2021. We combine 476 DEMs derived from SPOT5-HRS satellite images (2006–2008) and 2 525 DEMs of the Reference Elevation Model of Antarctica (2020–2022) to map elevation changes for the entire Peninsula. We vertically adjusted each DEM using near-coincident ICESat/-2 laser altimetry measurements. Our observations cover 70 % of the AP Ice Sheet and 60 % of its peripheral glaciers, including regions of the Peninsula poorly studied to date, and reveal a spatially complex pattern of elevation changes. After correction with different models of firn air content and solid-earth response, we find that between 2007 and 2021, the AP Ice Sheet lost -27 ± 9 Gt/a while its peripheral glaciers lost -14 ± 2 Gt/a. For the AP Ice Sheet, our new estimate is four to five times more negative than the one obtained in IMBIE using altimetry data (-5.2 ± 2.3 Gt/a from 2007 to 2019) and in better agreement with gravimetry and the mass budget method. Our study highlights the importance of resolving fine scale elevation changes of glaciers and ice sheets in complex, dynamic coastal areas.