Constraining the geometry and volume of the Barents Sea Ice Sheet

Abstract

ABSTRACTThe ice load configuration of the Barents Sea Ice Sheet (BSIS) over the last glacial cycle is in dispute. The traditional reconstruction, motivated by the observation that paleo‐shoreline emergence increases towards the center of the Barents Sea, places a single dome in the center of the Barents Sea at the Last Glacial Maximum (LGM) that collapses to island‐centered loads during deglaciation. Observations that suggest that ice flowed from the islands into the Barents even at the LGM motivate another reconstruction that places the ice loads over the islands with minimal marine ice. We analyze an ensemble of ice loads that are consistent with the geophysical observations and show that current relative sea level, GPS and gravity measurements do not and cannot distinguish a central dome from an island‐centered BSIS. What is needed are constraints in the central Barents. Improving the gravity data sufficiently will be difficult. However, obtaining even a single GPS uplift rate measurement in the central Barents would resolve the central dome versus island‐centered BSIS geometry question. Uncertainty in the Barents Sea ice load geometry provides a good illustration of statistical methods that we believe will be useful in other areas of glaciology.