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"Slow" surge of the Vavilov Ice Cap, Severnaya Zemlyaтезисы доклада Тезисы
- Авторы: Glazovsky A., Bushueva I., Nosenko G.
- Сборник: IASC Workshop on the dynamics and mass budget of Arctic glaciers
- Тезисы
- Год издания: 2015
- Место издания: IASC Obergurgl
- Первая страница: 17
- Последняя страница: 18
- Аннотация: We use satellite imagery (1963-2015) and airborne radar data (September 2014) to document rapid acceleration and surge of western sector of the Vavilov ice cap, Severnaya Zemlya. In the 1960s-70s, the ice margin there was stable and followed the general smooth outline. Only slight advance by 80 meters in average occurred in this decade. Thereat the margin was land-terminated and separated from sea by rampart of “dead” sediment-laden ice up to 0.5 km width. In 1980s- 2000s the margin began to bulge towards the sea with mean rate 70 m a−1, so that in 2012 the outlet lobe of 2.4 km length, 8 km width, and 12.36 km2 area was formed. When advancing it pushed forward the “dead” ice belt that framed the front. In 2012, the protrusion of front dramatically accelerated: rate of advance increased from 180 to 1540 m a−1 (maximum up to 2.4 km a−1). In September 2014 the area enlargement rate reached 37 000 m2 d−1.The surging lobe with 3.142 km3 of ice occupied an area of 30.14 km2, and embossed into the sea by 4.5 km. Its thickness reached 178 m (104 m mean), with bedrock at average depth −40 m (minimum −67 m) below sea level. The framing rampart almost completely collapsed; the margin spread and spitted into fingers, but, nevertheless, it advanced further by February 2015. Only shallows waters seems to prevent the major eruption of icebergs and front destruction. Radarograms show no large barriers or overdeepenings on bedrock, but reveal a feature that might be remains of marginal structure of 1963, also traceable through ice on imagery. Possibly, it is the roots of the cold-based plugging belt that was in most part cut off and pushed to the sea, where ice movement accelerated on soft unfrozen marine sediments.
- Добавил в систему: Глазовский Андрей Федорович