Fragmentation and melting of the seasonal sea ice cover

Lead Research Organisation: University of Reading
Department Name: Meteorology

Abstract

Recent years have seen a rapid reduction in the summer extent of Arctic sea ice. These changes have altered the local climate, affected navigation, oil exploration, wildlife and local communities, and are predicted by climate models to have significant implications for the weather and climate at lower latitudes, including NW Europe.

In winter, the sea ice cover of the Arctic Ocean comprises a mosaic of interlocking floating sea ice floes, mostly frozen together, with typical widths of 10-2000m, and thicknesses of 0.1-5m. In summer, the floes can melt apart. The representation of sea ice in climate models treats the floes as all being of the same size, around 300m. This simplification is particularly likely to affect model simulations in the edge region of the ice cover (known as the marginal ice zone) and in the largest part of the ice pack: the seasonal ice zone, which is the region that melts away every summer. This is because these regions are more strongly affected by ocean waves, which can break up the ice cover to create smaller floes. The reduction in floe size affects the response of the ice cover to incoming ocean waves and promotes lateral melting. Smaller floes have an enhanced lateral melt when ocean the ocean is warm, accelerating summer sea ice retreat.

The process of floe breakup is currently absent from climate models, and its contribution to ice-climate feedbacks, relative to surface melt, will be evaluated in this project. The PhD student will (i) examine the factors controlling the floe size distribution in the seasonal and marginal ice zone; (ii) examine lateral melt in a climate sea ice model; and (iii) examine the impact of lateral melting a coupled climate model.

This project brings together experts in sea ice physics and modelling at the Centre for Polar Observation and Modelling in the department of Meteorology at the University of Reading with experts in climate models at the Met Office Hadley Centre. The student will work closely with both groups.

Publications

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