One week on

It has been a sobering week. At the time we were initially caught by the sea ice, the Shokalskiy was just 2 to 4 nautical miles from open water. Now the sea ice distance has become even greater with the continued winds from the east, putting our nearest point of exit at some 16 nautical miles. The international effort has been extraordinary and we are incredibly grateful for all the hard work and effort everyone has provided to assist the Australasian Antarctic Expedition 2013-14 in escaping from the ice – a big thanks in particular to the Chinese, French and Australians, co-ordinated by the Australian Maritime Rescue Centre. The winds have eased slightly but at times have reached in excess of 70 kilometres an hour – equivalent to the average conditions experienced by Sir Douglas Mawson’s original expedition a century ago at Cape Denison. It is humbling to consider these men not only survived but thrived, mounting a major scientific expedition. A continent of extremes was revealed and communicated by the latest radio technology to the public at home.


The conditions we are experiencing over the Shokalskiy are a result of the frequent and deep low pressure systems that encircle the continent. In combination with a funnelling effect from the ice sheet, these lows are producing strong and pervasive winds from the southeast. The wind is not unusual but what is unexpected is the major reconfiguration of thick multi-year sea ice to the east of the Mertz Glacier. In 2010, a large iceberg known as B09B, calved from the continent and collided spectacularly with the extended tongue of the Mertz Glacier. The knock-on effect has been that Commonwealth Bay has filled with sea ice (termed ‘fast ice’), preventing direct access from the sea to Mawson’s main hut at Cape Denison. Unfortunately for the AAE, it appears the region has just undergone a massive reconfiguration of sea ice, years after the loss of the Mertz Glacier tongue. This has been revealed by new satellite imagery which arrived today from the AAD/ACE CRC Sea Ice Group in Hobart, Tasmania. The satellite maps show the comparison before and after the event, with deep purple signifying 100% sea ice cover and dark blue, open water. (Note: the outline of the Mertz Glacier tongue is shown on the maps but disappeared following the collision with B09B). Crucially, these images show the extensive, thick multi-year sea ice along the eastern and southern edge of what was the Mertz Glacier Tongue (outlined by a red box) has been blown out in the last week and driven against our position by the persistent southeasterly winds. It is too early to identify the cause of this remobilisation of ice but we may be looking at the future long-term expansion of fast ice to the east of Commonwealth Bay.
The thick chaotic surface we see around the Shokalskiy is consistent with the idea that this ice is several years old and is considerably more difficult to break through by icebreaker than single year ice. The presence of dark watersky to the southeast shows the presence of open water which is reflecting off the underneath of clouds. We hope the Australian ice breaker Aurora australis may have more luck finding leads from this ice edge to reach the Shokalskiy. We are all hoping the Shokalskiy will find a route out thanks to the efforts of the Australian and Chinese icebreakers.
Meanwhile on board the Shokalskiy, moral remains good and the team are pulling together in an extraordinary way. Everyone is working hard to support one another. Take a look at the video diaries on the Intrepid Science YouTube Channel to see what we are up to. We are all keeping busy, with twice daily briefings outlining all the information we have to hand, alongside classes through the day (knot tying, languages, yoga, photography and many others) while the science programme has continued as best we can.
Thanks for all your support and we hope to see you all soon.
By Chris Turney (at +Intrepid Science)

Comments

Post a Comment

Popular posts from this blog

500 years of drought and flood: trees and corals reveal Australia’s climate history

Image
500 years of drought and flood: trees and corals reveal Australia's climate history Patrick Baker , University of Melbourne ; Chris Turney , UNSW Australia , and Jonathan Palmer , UNSW Australia Australia is the land of drought and flooding rains, and in a recent paper we’ve shown that’s been the case for more than 500 years. As part of our Australia and New Zealand Drought Atlas we’ve published the most detailed record of drought and wet periods (or “pluvials”) since 1500. The data reveal that despite the severity of the Millennium Drought, the five worst single years of drought happened before 1900. But 2011 was the wettest year in our 513-year record. The dominant theme of Australia’s drought history is variability. We may get one year of extremely wet conditions (for example in 2011) or we might get six years of extremely dry conditions (such as 2003-2009). North Queensland may be flooded out while Victoria suffers with drought. Or in extreme circumstances, the entir...
Read more

The Tropics and the Furious Fifties

Image
There’s an old sailor’s expression: “Below 40 degrees south there is no law, below 50 degrees south there is no God.” Since the sixteenth century, sailors have spoken in awe of the violent westerly winds and seas they experienced fighting their way across the Southern Ocean. With few landmasses to slow them down, the winds found across 40 degrees latitude often reach speeds of twenty-five knots—about 40 percent stronger than their northern hemisphere counterparts—earning them the title the “roaring forties.” As shipping pushed farther south, explorers realized that these winds form part of a vast storm belt that includes the “furious fifties” and “screaming sixties,” names more reminiscent of terrible rock bands than a major part of our planet’s circulation system. The early hunters and traders didn’t understand it at the time, but these winds are created by a procession of low-pressure systems carried east by the jet stream, a river of cold air hurtling and twisting round the Antarct...
Read more

Death of a colony

Image
Cape Denison holds a special place in the history of Antarctic exploration. A small outcrop of rocks on the remote East Antarctic coastline, Cape Denison is forever associated with one of the most spectacular and often forgotten tales of survival. A century ago it was the main base of operations for one of the great explorers of the south: the Australian scientist Sir Douglas Mawson . Privately funded, three bases and one research ship supported a science team that explored a region the size of the United States between 1911 and 1914. Mawson’s Australasian Antarctic Expedition, however, suffered terribly during their time at Cape Denison: a sudden turn of events led to tragedy on the ice, the death of two men, allegations of cannibalism and with the return of winter sea ice, an extended stay in Antarctica. But when they first came upon Cape Denison, Mawson was ecstatic. Greeted by squawking penguins: ‘ We were soon inside a beautiful, miniature harbour completely land-locked. The su...
Read more