Velocity structure, front position changes and calving of the tidewater glacier Kronebreen, Svalbard

Abstract

Glacier calving and retreat constitute a substantial portion of the ablation of tidewater glaciers and is therefore of interest in climate models in order to get more accurate predictions of future development of glaciers and their contribution to sea level rise. We use photogrammetry, global navigation satellite system, surface elevation and bathymetric data from Kronebreen to test a crevasse-depth calving model, investigate meteorological controls on near terminus velocity fluctuations and finally short-term and longer term (multi annual to decadal) controls of the front positions and calving. The relationship between velocity structure, crevasse formation, and calving events at Kronebreen is found to be more complex than outlined in the crevasse-depth calving model. Surface meltwater is found to be closely connected to velocities, but no direct relationship between velocity variation and calving could be seen along the investigated transect. On a long term basis the front positions of Kronebreen are results of a combination of several factors, particularly the interplay with the confluent glacier Kongsvegen, and change in discharge fluxes as a result of surge dynamics. Yet the bed topography is found to be an important control on the retreat of this glacier, similar to several other tidewater glaciers.