When the icebreaker Aurora Australis left Hobart in March this year, the voyage heralded a step-change in science’s ability to explore the Southern Ocean – a vast area of the roughest and wildest waters on the planet. The sailing was part of the Climate of Antarctica and the Southern Ocean project (CASO), the lead in an international cluster of similar projects in the Antarctic Ocean Circulation program of the International Polar Year (IPY).
The science of IPY has been driven by researchers from 63 nations, motivated by urgency and a need to understand the poles and their relation to the rest of the planet. With more than 250 projects, IPY is giving the world an opportunity to harness the collective resources of oceanographic organisations, to take a snapshot of the polar regions in unprecedented detail during a single season.
CASO aims to obtain the first-ever circumpolar snapshot of the Southern Ocean, using the latest technology in a collaboration by oceanographic institutes around the world. It is also complemented by a raft of other IPY programs targeting the biology and chemistry of the Antarctic oceans. This summer’s voyage was led by the Antarctic Climate & Ecosystems Cooperative Research Centre (ACE CRC), the final sailing in a schedule of more than a dozen expeditions by 18 nations to put together the most comprehensive picture of the region yet taken. The season saw the largest-ever fleet of scientific vessels converge on the Southern Ocean and marked the start of the first international polar ocean–climate study in over a decade.
The ocean and its relationship with the polar regions plays a key role in global climate by storing and transporting vast amounts of heat and carbon dioxide – if the ocean was not so effective at soaking up heat and carbon, the rate of greenhouse warming would be much greater than the world has experienced so far. Better observations of the polar regions are critical to forecast the implications of this warming for future climate change. In global terms, the Southern Ocean is especially important: it absorbs more heat and carbon than any other part of the ocean and it is the only place where large amounts of water can be exchanged between the other major oceans – the Indian, the Pacific and the Atlantic.
In particular, the belt of ocean circling Antarctica – the Antarctic Circumpolar Current – is an important driver of the Earth’s climate. The largest and deepest current in the world ocean, it rings the Antarctic unimpeded by land and influences climate and ocean circulation patterns over much of the globe. The current is in turn driven by a similarly influential and unobstructed circumpolar atmospheric flow, the notorious Roaring Forties and Furious Fifties that blow from west to east around the Antarctic continent largely without obstacle. Together, these tempestuous winds and driving seas have been a long-term barrier to detailed scientific exploration, making the current IPY circumpolar snapshot particularly notable and important.
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http://www.sciencealert.com.au/features/20080809-17920.html