In the Northern Hemisphere, ~1500 glaciers, accounting for 28% of glacierized area outside the Greenland Ice Sheet, terminate in the ocean. Glacier mass loss at their ice-ocean interface, known as frontal ablation, has not yet been comprehensively quantified. Here, we estimate decadal frontal ablation from measurements of ice discharge and terminus position change from 2000 to 2020. We bias-correct and cross-validate estimates and uncertainties using independent sources. Frontal ablation of marine-terminating glaciers contributed an average of 44.47 ± 6.23 Gt a−1 of ice to the ocean from 2000 to 2010, and 51.98 ± 4.62 Gt a−1 from 2010 to 2020. Ice discharge from 2000 to 2020 was equivalent to 2.10 ± 0.22 mm of sea-level rise and comprised approximately 79% of frontal ablation, with the remainder from terminus retreat. Near-coastal areas most impacted include Austfonna, Svalbard, and central Severnaya Zemlya, the Russian Arctic, and a few Alaskan fjords.

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GPS measurements of tidal modulation of ice flow and seismicity within the grounding zone of Beardmore Glacier show that tidally induced fluctuations of horizontal flow are largest near the grounding line and decrease downstream. Seismic activity is continuous, but peaks occur on falling and rising tides. Beamforming methods reveal that most seismic events originate from two distinct locations, one on the grid-north side of the grounding zone, and one on the grid-south side. The broad pattern of deformation generated as Beardmore Glacier merges with the Ross Ice Shelf results in net extension along the grid-north side of the grounding zone and net compression along the grid-south side. During falling tides, seismic activity peaks on both sides because of increased vertical flexure across the grounding line. During rising tides, seismic activity in the region of extension on the grid-north side is relatively low because the tidal influence on both horizontal strain rate and vertical flexure is small. On the grid-south side during rising tides, however, tidally induced horizontal strain rates promote increased seismicity in regions of long-term compressional flow paths. Our study highlights how concurrent geodetic and seismic measurements provide insight into grounding-zone mechanics and their influence on ice-shelf buttressing.

A study of recrystallisation texture evolution was performed in an ageable Al-Mg-Si alloy to assess the sheet formability of autobody sheet before age hardening, by using quantitative orientation distribution function (ODF) determination during presolutionising anneal treatments. It was found that preannealing of cold rolled sheet near 250uC results in the largest amount of cube texture upon subsequent solutionising at 560uC. The apparent activation enthalpy is near 2?5 eV if the iron solute content is below 0?5 ppm atomic. The formation of cube oriented grains occurs below 300uC and grain growth above this temperature appears to be inhibited by iron solute drag of the grain boundaries. It was discovered that the volume fraction ratio of the cube and {02 1} ,100. is correlated to the average R value.