High Resolution Mapping of the Cold/Temperate Transition Surface of the Polythemal Glaciers Midre Lovenbreen and Austre Lovenbreen, Svalbard

Abstract

An extensive ground penetration radar (GPR) survey across the snout of the polythermal Midre Lovénbreen, Svalbard, has revealed the precise location of the downglacier transition between cold and warm ice (the cold/temperate transition surface). This work revealed that a surprisingly rapid upglacier retreat of this boundary has occurred over the past 16 years – much more rapid than the rate of snout retreat in response to a long-term negative mass balance. Such rapid response of the thermal structure to ice thinning suggests that the hydrology and dynamics of polythermal glaciers may respond in a complex way to a warming climate. Extensive GPR data were also collected over the whole of the nearby Austre Lovénbreen – the first ever such GPR survey. Although these data have not yet been analysed in detail, preliminary analysis indicates that this glacier is also polythermal, and likely behaves in a way similar to Midre Lovénbreen.