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GEOS 110 FALL 2011. SEA ICE. Polynyas – openings in the ice. Persistent, forming year after year 2 types: Sensible & Katabatic. Polynyas – openings in the ice Katabatic – Dense Drainage Winds.
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GEOS 110 FALL 2011 SEA ICE
Polynyas – openings in the ice • Persistent, forming year after year • 2 types: Sensible & Katabatic
Polynyas – openings in the iceKatabatic – Dense Drainage Winds
Understanding and Projecting the Changes in the Oceanic Conveyor Belt is a Critical Question for Science
Arctic inflow Arctic outflow The North Atlantic Current provides about 60% of the inflow to the Arctic Ocean bringing warmer water from the Atlantic Ocean. Some water also moves into the Arctic Ocean from the Bering Sea and the Pacific Ocean, by way of the Bering Strait. Water flows from the Arctic Ocean into the Pacific and Atlantic Oceans, as well as into a number of surrounding seas. By far, the greatest volume of water leaves the Arctic Ocean through the passage between Greenland and Spitsbergen.
observations vs. models IPCC FAR model ensemble mean of all models observed sea ice decline is 50 years ahead of expectation from models forced by GHG’s (and other human and natural radiative forcings discussed earlier) suggesting models do not capture all relevant interactions
“A linear increase in heat in the Arctic will lead to a non-linear, and accelerating, loss of ice”
impacts of an summer-ice free Arctic ? • sharply warmer Arctic Autumn and Winter from increased O-A heat fluxes (polar amplification of warming) • local ecological and human impacts • altered weather patterns outside the Arctic (due to altered patterns of heating and pressure) • altered salinity and ocean circulation no evidence of summer-ice free Arctic in last million years