The evolution of a large glacier surge of Vavilov Ice Cap, Severnaya
Zemlya, since 2013
Abstract
The Vavilov Ice Cap destabilized in 2013. It reached its highest annual
ice loss rate of 4.48 km3/yr between 2015 and 2016, a rate that is more
than half of the entire combined ice loss from all the other ice caps in
the Russian Arctic. To understand the mechanics of how the surge took
place and what will happen in the future, we investigate surface
elevation and glacier velocities using the Cryosphere And Remote Sensing
Toolkit (CARST), an open-access python toolbox designed for processing
temporal changes of high-resolution remote sensing data. We use optical
satellite images from WorldView, Landsat, and Sentinel-2 and their
derived elevation and velocity products to track the history of the
surge between 2010 and the present. We propose that the surge initiated
when the ice front overrode weak marine sediments in 2013, leading to a
reduction of frontal friction. Velocity time series show that the
glacier reached a maximum speed of 25 m/day (9 km/yr) in late 2015, when
a piedmont-like ice lobe stretched more than 10 km into the Kara Sea.
However, in spring 2017 the glacier slowed down to 7-9 m/day with the
development of a new channel inside the piedmont lobe, with new shear
margins visible from optical imagery. The channelized flow pushes
through the grounded portion of the piedmont glacier, and suggests a
further reorganization of resistive forces. The unprecedented evolution
of the surge at Vavilov Ice Cap shows a strong connection to the status
of the terminus, which might pose general concern for the stability of
marine- or lake-terminating glaciers regardless of their locations on
Earth.