The Antarctic Ice Sheet and its Role in the Global System

Abstract

The most conspicuous property of Antarctica is its ice mass — most of the Antarctic continent’s landmass is covered by ice — ice sheets, glaciers, ice streams and ice shelves. All these features consist of ice and may thus be summerized as “glaciers”, but have different properties. An ice sheet covers large land areas and is flat and wide, the ice in the ice sheet flows at a low velocity, following gravitational forces, generally towards the ice sheet’s margin. An ice stream is an area of ice flowing at a higher velocity than the surrounding inland ice, large ice streams drain the inland into the Circum-Antarctic ocean. The lower part of an ice stream draining into the ocean becomes afloat (at the line termed the grounding line), it forms a floating tongue. Many Antarctic ice streams and glaciers end in ice shelves, areas of ocean water covered by thick ice (more glaciologic terms are explained in the glaciologic glossary, section (I.1)). Often several glaciers and ice streams end in the same ice shelf, but there are also coastal areas of Antarctica that are not bordered by ice shelves. For instance, the Atlantic Ocean sector is fringed by ice shelves, with large ice streams flowing into those, including Slessor Glacier, Jutulstraumen, Stancomb-Wills Glacier and Recovery Glacier. Examples of coastline without ice shelves are Mawson Coast (W of Lambert Glacier), Knox Coast and Sabrina Coast in Wilkes Land.