Breaking the ice

37,552 tourists visited Antarctica between 2006 and 2007

More tourists than ever before are visiting the great white continent.

The International Association of Antarctica Tour Operators shows that 37,552 tourists visited Antarctica between 2006 and 2007, with the majority arriving by sea.

However, the water around the continent is a dangerous place, as the passengers on board the M/S Explorer found out last year when the liner hit an iceberg and sank.

With more people visiting and the concomitant increase in the number of ships, it is becoming increasingly important to find ways of navigating safely and avoiding future collisions.

The Antarctic Polar View project is using satellites to map the sea ice, to help ships find the best - and safest - route.

Anna Lacey went to the British Antarctic Survey in Cambridge to find out about a new project that's using satellite technology to improve navigation in the Southern Ocean for the BBC World Service's Digital Planet programme.

Pretty dangerous

"There are very large lumps of heavy ice in the water, that might look pretty in white with penguins dancing on top of them, but trust me you don't want to hit them very fast with a ship," said Andrew Fleming from the British Antarctic Survey who is leading the research.

"If you do, you are going to damage your ship and therefore navigating through it is a problem, not only in terms of the safety of the ship but in terms of the speed of the ship and the efficiency of the ship.

"So, you don't want to spend an excessive amount of time going through an area of very thick ice when you could be taking a quicker and therefore cheaper route," he added.

Antarctica may look beautiful but it can be a dangerous place

"The area we're dealing with is absolutely enormous; the only way of monitoring that area of ocean effectively is using satellites.

"We use a satellite called Envisat, which is a radar satellite that picks up differences in ocean surface roughness and that allows us to see the difference in open water and the sea ice," said Mr Fleming.

The radar allows the team to see straight through the clouds down to the surface of the sea. With detailed images, it's even possible to see the cracks in sea ice, which can lead to dangerous ice falls.

Robb Clifton, who works for the Australian Antarctic Division as a voyage leader, is someone who knows how useful these satellite images are in practice.

"Wherever possible, we would use helicopters quite a lot and put them up in the air to map the ice and look for where we might find what we call 'leads' - you know which are large areas of clear water, that the ship might be able to move through," he said.

"But it was certainly a much more difficult, time-consuming operation," he added.

Making the most of it

Although the Antarctic Polar View Project is hugely useful, there are some ways in which it could be improved.

"We can't yet determine the thickness of the sea ice but one of the science programmes that we were doing last summer was looking at doing some of that work using satellites as well, and that's going to be quite an exciting development," said Mr Clifton.

The maps of the sea are coloured in various shades of grey, with the dark areas being the smooth open water and the light areas identifying the textured areas of sea ice.

However, taking the image is only the first step as it then has to be sent to the ship.

"Internet connections in the Antarctic and on ships are notoriously poor and that has meant that we have ended up cropping the image, compressing it a lot and losing a lot of the detail in the image as a result," said Mr Fleming.

Internet connections in the Antarctic and on ships are notoriously poor Andrew Fleming

"So, we have to find a way of getting imagery that is very large [and sending it] down that very narrow bandwidth to the users on the ship," he added. One way they're doing this is by compressing the images into a format known as JPEG2000.

"JPEG2000 allows us to compress the image a lot more and secondly it allows us to preserve the geographic position of the image, so it knows where the image is and allows us to position it on a map.

"On the other hand, we are using a system that now allows us to deliver that image in bite size chunks.

"What we deliver first of all is just a low-resolution image of the entire area and then the user can choose what he wants detail of, zoom into that area and then our system only delivers the higher resolution information of that particular area," said Mr Fleming.

Although the system is fairly new, it's already making an impact for those who sail the seas.

"We now know fairly well the kind of sea ice conditions we are likely to encounter, so it's a fantastic and very easy-to-use and easy-to-interpret system that we just run off a laptop on the bridge of the ship," added Mr Clifton.

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