Publication Date:
2023-07-19
Description:
While the mass loss of alpine glaciers through melting responds to atmospheric changes over years or even decades, the dynamic response of glaciers can change abruptly. Particularly for marine or lake terminating glaciers, single weather events can cause changes in ice flow velocity and terminus position. Occasionally, this can lead to event-driven massive mass loss at the ice front due to calving. We evaluate changes in terminus position, ice flow velocity, and calving flux at the exemplary glacier Schiaparelli in the Cordillera Darwin on very high spatial and temporal scales using geo-referenced time-lapse camera images from 2015 to 2022. In addition, remote sensing data (Sentinel-1) provide a spatial view of the ice flow over the entire ablation area. Lake level records, runoff measurements, and a coupled energy and mass balance model allow us to quantify the contribution of meltwater to glacier runoff and its discharge efficiency. We use downscaled reanalysis data (ERA-5) to identify climate extremes, and track land-falling atmospheric rivers, to investigate the dynamic response of the glacier. Seasonal velocity variations are controlled by meltwater, alternating between an efficient in the warm season and an inefficient drainage system in the cold season. The calving flux peaks within three days after the onset of a warm spell or the landfall of an exceptionally warm atmospheric river. There is no evidence of flow velocity changes due to single (extreme) calving events. The observations highlight the positive feedback mechanism between glacier thinning and terminus length changes, ice flow acceleration, and calving flux.
Language:
English
Type:
info:eu-repo/semantics/conferenceObject
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