Winds warm up the West Antarctic, driving ice loss

Tuesday 18 July 2017
This image shows the path of Kelvin waves around the West Antarctic Peninsula, where they interact with the steep ocean floor and the Antarctic Circumpolar Current to drive warm water beneath the ice shelves, driving rapid melting in this region.

New research published today in Nature Climate Change has revealed how strengthening winds on the opposite side of Antarctica, up to 6000kms away, drive the high rate of ice melt along the West Antarctic Peninsula.

Researchers from the ARC Centre of Excellence for Climate System Science found that the winds in East Antarctica can generate sea-level disturbances that propagate around the continent at almost 700 kilometres per hour via a type of ocean wave known as a Kelvin wave.

When these waves encounter the steep underwater topography off the West Antarctic Peninsula they push warmer water towards the large ice shelves along the shoreline. The warm Antarctic Circumpolar Current passes quite close to the continental shelf in this region, providing a source for this warm water.

“It is this combination of available warm water offshore, and a transport of this warm water onto the shelf, that has seen rapid ice shelf melt along the West Antarctic sector over the past several decades,” said lead researcher Dr Paul Spence.

“We always knew warm water was finding its way into this area but the precise mechanism has remained unclear. That remote winds on the opposite side of Antarctica can cause such a substantial subsurface warming is a worrying aspect of the circulation at the Antarctic margin.”

The changes in the Antarctic coastal winds, particularly along East Antarctica, might themselves be related to climate change. This is because as the Earth warms the strong westerly winds associated with storms over the Southern Ocean contract toward the poles, in turn changing the winds near the Antarctic continent.

When the researchers used National Computational Infrastructures super computers to model the impacts of these altered winds on Antarctica, they found that they could drive warming of up to 1°C of the waters at the depth of floating ice shelves along the Western Antarctica Peninsula.

This could have significant implications for Antarctica’s ice shelves and ice sheets, with previous research showing that even small increases in ocean temperatures can substantially increase melt rates around the Peninsula.

Associate Professor Andy Hogg, from the Research School of Earth Sciences, is a co-author of the study. He said, "This research shows that we are still discovering the different mechanisms that control the rate of melting of Antarctic glaciers."

About

The ARC Centre of Excellence for Climate System Science is the largest university-based climate research centre in the Southern Hemisphere. It is funded by the Australian Research Council. The Centre is an international research consortium of five Australian universities and a suite of outstanding national and international Partner Organisations.

NCI Australia is the nation’s most highly-integrated, high-performance research computing environment. NCI is built to deliver on national priorities and research excellence from across the scientific disciplines. Based at The Australian National University, it provides integrated high-performance computing and high-performance data services to over 4000 researchers at a number of the national science agencies.

Updated:  17 August 2017/Responsible Officer:  RSES Webmaster/Page Contact:  RSES Webmaster