Remote Sensing Observations of Advancing and Surging Tidewater Glaciers

Robert McNabb, Andreas Kääb, Christopher Nuth, Luc Girod, Martin Truffer, Mark Fahnestock

Research output: Contribution to conferenceAbstract

Abstract

Progress has been made in understanding the glaciological frontiers of tidewater glacier dynamics and surge dynamics, though many aspects of these topics are not well-understood. Advances in the processing of digital elevation models (DEMs) from ASTER imagery, as well as the increased availability and temporal density of satellite images such as Landsat and the Sentinel missions, provide an unprecedented wealth of satellite data over glaciers, providing new opportunities to learn about these topics. As one of the largest glaciated regions in the world outside of the Greenland and Antarctic ice sheets, glaciers in Alaska and adjacent regions in Canada have been highlighted for their elevated contributions to global sea level rise, through both high levels of melt and frontal ablation/calving from a large number of tidewater glaciers. The region is also home to a number of surging glaciers. We focus on several tidewater glaciers in the region, including Turner, Tsaa, Harvard, and Meares Glaciers. Turner Glacier is a surge-type tidewater glacier with a surge period of approximately eight years, while Tsaa Glacier is a tidwewater glacier that has shown rapid swings in terminus position on the order of a year. Harvard and Meares Glaciers have been steadily advancing since at least the mid-20th century, in contrast with neighboring glaciers that are retreating. Using a combination of ASTER, Landsat, and Sentinel data, we present and examine high-resolution time series of elevation, velocity, and terminus position for these glaciers, as well as updated estimates of volume change and frontal ablation rates, including on sub-annual time scales. Preliminary investigations of elevation change on Turner Glacier show that changes are most pronounced in the lower reaches of the glacier, below a prominent icefall approximately 15km from the head of the glacier. On Harvard and Meares Glaciers, elevation changes in the upper reaches of both glaciers have been generally small or even negative, corroborating patterns of change seen in other studies, and casting doubt on the ability of these glaciers to sustain their advances. These observations, and others like them, provide key insights into tidewater glacier dynamics, enabling better understanding of these processes.
Original languageEnglish
Publication statusPublished - 15 Dec 2017
EventAGU Fall Meeting - New Orleans, United States
Duration: 11 Dec 201715 Dec 2017

Conference

ConferenceAGU Fall Meeting
CountryUnited States
CityNew Orleans
Period11/12/1715/12/17

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