Long-Term Volume Loss From a Svalbard Catchment Contrasts Between a Surge-type and Non-Surge-Type Glacier

Grønfjordbreen and Fridtjovbreen are two small valley glaciers that flow northwards and southwards, respectively, from an ice divide in central west Spitsbergen. Grønfjordbreen is a slow flowing, non-surge-type glacier with volume changes dominated by changes in surface mass balance. Fridtjovbreen, in contrast, initiated a surge with gradually increasing velocities during the early 1990s with peak flow occurring during 1996. We compare DEMs produced in 1956, 1969 and 1990 using aerial photographs with a lidar DEM collected in 2005 to measure volume changes over this 49 year period and to contrast the changes due to surge behaviour with those occurring due to climatic change. Results have shown that, in common with other surge-type glaciers, dynamic changes have controlled the recent changes in the geometry of Fridtjovbreen including approximately 1800 m of advance since 1990, 136 m of thickening in the receiving zone and 80 m of thinning in the reservoir zone.