Mapping the Changing Extent and Thickness of Arctic Multiyear Sea Ice

Abstract:

Satellite remote sensing provides continuous observations of the sea ice pack across basin scales and has revolutionized our understanding of ice mass balance over the last two decades. Satellite and airborne altimeters deliver a unique set of measurements of sea ice elevation, from which thickness may be derived. Recent analyses provide details on the interannual variability of Arctic sea ice thickness and volume, superimposed on a multi-decadal decline. Results indicate that the largest losses are to the multiyear ice (MYI) cover. A declining MYI cover will precondition the pack for further loss, severely altering the mass and energy budgets.

Advancing our understanding of how and why the MYI cover is changing is therefore critical for improved predictions of the future Arctic climate system. Using seven years of high-resolution Operation IceBridge airborne measurements with complementary satellite radar imagery and scatterometry data we map the interannual variability of the MYI pack. We describe key features including the variability and trends in the thickness distribution and extent. During this period mean ice thickness was around 3.2 m with a modal thickness of 2.8 m. We examine the influence of dynamic processes on recent variability, gaining new insights on the age, thickness and morphology of the MYI pack.