Professor Mary-Louise Timmermans
Summer heat overwinters in the Arctic Ocean
The talk will address the implications of a warming Arctic Ocean on the overlying sea-ice cover. In recent years, atypically warm water layers have been observed at depth in the Arctic Ocean. These derive from intense summertime solar heating in expansive ice-free regions. Heat that is stored in the shallow ocean can be released in the fall and winter by shear-driven mixing, and convective mixing by the release of dense plumes during sea-ice growth, reducing the net sea-ice growth. On the other hand, deeper warm ocean layers remain unaffected. I'll show that under continued warming, there exists the possibility for a regime shift in ocean ventilation by these warm waters, and a subsequent cap on the storage of deep-ocean heat.