Wednesday, April 25, 2007

Some Real Survey Work

The last few weeks have focused on ensuring the base is ready for the disappearance of the sun. With the last pre-darkness winter trip back on base, there have been a few last pieces of off-base science work to complete.

Sunset Over the Drewry

One of these meant an opportunity for me to escape with Sune (Field Assistant) for a day, to carry out some survey work to provide data for the glaciologists working on the Halley long term survival project, attempting to predict when the next calving event of the Brunt Ice Shelf is likely to occur. By collecting highly accurate GPS (Global Positioning System) data on a 3-monthly basis from a network of stations around the ice shelf, any unusual change from the baseline measurements, could indicate the presence of a crack and would provide warning of a potential calving event.

Collecting GPS Data

The yellow briefcases hold highly accurate GPS equipment, which supposedly allows the resolution of the position on a point on the globe down to less than a centimetre using multiple satellites. They do come, however, come with a disclaimer that they cease to function when travelling of speeds greater than 1000 knots per hour, ensuring that they would be of little use on an intercontinental ballistic missile! Fortunately, they are also fairly robust as travelling around on the back of a ski-doo for the 60 kilometre round trip is enough to destroy quite a lot of things particularly at -35°C.

Sunset On The Brunt
Sune finishes off the survey work

It is batteries, however, that are the limitation to work at this temperature, be that powering the GPS units, in the UAV, starting a bulldozer or in the ubiquitous digital cameras. All types of battery have a particularly limited life but can be temporarily resuscitated by warming them up. Digital photography and field work therefore require either a heat pack to keep the battery as warm as possible or in the case of the former, a succession of batteries being rotated from pockets to camera and back again. Moreover, the ski-doos, which have a pull-cord to supplement the battery in starting them, will not tolerate temperatures much colder than -35°C either, meaning that field work late in the season is hampered by temperature as well as darkness.

Fog Comes In Off The Weddell Sea

Even for the day's travelling around the Brunt between Halley, the Rumples (see map) and the survey points, though we were never further than 30 kilometres from base (20 miles), between the two ski-doos it is obligatory to carry a standard half unit sledge, effectively an emergency pack in case the weather changes rapidly or a ski-doo breaks down. No different from the sledges taken on the winter trips, they carry enough food, in the shape of Man-food boxes (as opposed to the now non-existent Dog-food boxes), along with fuel, tents, radios and spares to survive six weeks in the field. Amongst boxes carried on the sledge is the Field Medical Box.

Contents of a Field Medical Box

Packing and checking the several field medical boxes forms one of my more tedious jobs. They supplement the Immediate Aid Packs (First Aid packs) carried out in the field. The boxes contain an enormous range of drugs and medical supplies to deal with a wide range of eventualities that could occur not only 20 kilometres off base but also on the summer deep field projects, when immediate evacuation to a base may be infeasible due to huge distances and poor weather. The 106 different types of items carried range from Plaster of Paris kits to dental instruments, various antibiotics to injectable painkillers and spare sunscreen to airway adjuncts.

The Simpson at Sunrise

Given the absence of ambulances, all of those BAS personnel who go into the field undergo an extended first aid course, focusing on likely problems while South, moreover a few wintering personnel spent the best part of a week covering some more advanced topics with the BAS Medical Unit in Plymouth before coming away. Also in each of the boxes is a copy of Kurafid (as in Cure-A-Fid...) the BAS medical handbook now in its fifth edition, backed up by radio advice available from the base doctors on HF (High Frequency) radio should the need arise.

The Container Line
Shipping containers from a long line north of the base providing extra storage

The Field Medical Boxes end up weighing about 20kg (45lbs) and are of the standard Man-food box size such that they fit snugly on the sledges. Not only do the contents spend most of their time at below freezing temperatures, they are at risk should the lid fit loosely as fine snow has an ability to rapidly find any hole and fill the dead space, freezing rapidly to a solid block.

In The Piggott Tunnel

As sunlight is rapidly becoming a precious commodity, there is a slight pressure to ensure that the base is ready for the ensuing darkness and dropping temperatures. It has already hit -45°C and now lies frequently below -40°C (-40°F). Part of the work of the carpenter is to monitor the temperatures in the two tunnel systems that lie under the base. That meant a rare opportunity to see inside the smaller tunnel that lies underneath the Piggott platform, acting as a store for fuel and carrying cabling to scientific cabooses, too warm and the ice around starts to melt and buckle the shape of the tunnel, too cold and the contents freeze.

Ice Crystals in the Tunnel

The constant sub-zero temperatures in the tunnel has meant that some spectacular ice crystals have had the opportunity to form over years, illuminated by the pale orange lights. The previous two incarnations of the Halley base (Halley III and IV), were both underground installations but the pressure of the accumulated ice meant that they had to be abandoned. (The current German Antarctic base at Neumayer some 500 miles away is almost completely underground).

Moving Petrol Drums

The full complement of 18 people back on base has meant an opportunity to get us all in front of a camera for the first time. The dining room is lined with a photo of each of the wintering teams, classically in black and white and processed on base with a frame produced in-house, we have yet to claim our place on the wall but in the interim here we all are...

Halley 2007

1- David Evans – Meteorologist; 2- Andy McConnachie – Generator Mechanic; 3- Alex Gough – Data Manager; 4- Thomas SpieƟ – UAV Meteorologist; 5- Pete Milner – Base Commander; 6- Neil Brough – Air Chemist; 7- Richard Corbett – Doctor; 8- Sune Tamm-Buckle – Field Assistant; 9- Anton Dubber – Chef; 10- Dean Evans – Communications Manager; 11- Matt Richardson – Vehicle Mechanic; 12- Brian Hunter – Plumber; 13- Julius Rix – Electronic Engineer; 14- Mark Wales – Electrician; 15- Kirsty Stead – Meteorologist; 16- Tamsin Gray – Meteorologist; 17- James Morrison – Carpenter; 18- Chris Oakley – Electronic Engineer

The encroaching darkness has also meant some sleepless nights watching aurora- more next time.

The Aurora Australis and Jupiter Over The Laws

Saturday, April 07, 2007

Sun Dogs and Englishmen Go Out in the Midday Sun

Sun Rise Against Stratocumulus Clouds

Time runs away; now back from my winter trip and with the last trip due to return at any moment, the sun is disappearing rapidly. At the moment we are losing an hour of daylight every three days. That though, has not stopped the appearance of some spectacular atmospheric phenomena. The first are Sun Dogs or parhelia, which though they can be seen anywhere in the world, are more prevalent here at the moment as the sun runs a low arc across the horizon.

Sun Dogs

The shot above was taken at midday (note how low the sun is), over our satellite dome and HF (High Frequency) radio masts, which form our channel of communication with the outside world. There are a variety of phenomena related to the refraction of light through ice crystals (in this case fine crystals called 'diamond dust'), the photo below illustrates those we could identify on this occasion, though the nature of the lateral arcs, despite consulting all our textbooks is unclear. The parhelia given that they refract light have a similar appearance to a rainbow. For more information see Atmospheric Optics.

Halo, Arcs and Parhelia

Though, fortunately, there are significant periods of time when there is little for me to do medically, there is always plenty of need for an extra hand around base. The platforms (Laws, Simpson and Piggott) themselves need continual monitoring, due mainly not to the movement of the ice sheet as such, but the accumulation of snow around each of the legs.

Out Surveying With Jim

The responsibility for the surveying and maintenance falls on the base Carpenter, Jim, who celebrated his 21st birthday on the voyage South from Signy and is the youngest person on base. He, like everybody else, has had to learn new skills to cover all the jobs around base, so along with building shelves and refitting offices as accommodation for the increased number of people expected for the building work in the summer, has to learn the skills of a steel erector. This has meant a couple of cold afternoons hanging off the building in a harness, raising part of the platform, admittedly by fractions of millimetres at a time, to keep the whole thing level.

Jacking the Laws Platform
Jim and I raise the platform on one of its legs

A further expectation is that the base doctor bears some responsibility for baking birthday cakes, at least the previous two docs convinced me of this and so with Ant- our chef- away I had a go at my first one of the season, having found good reasons not to make any others to date.

Tom's Birthday Cake

Tom, our German UAV pilot and meteorologist, ended up with a frog due to a German connection between weather forecasting and frogs. Birthdays acquire a special significance here as they from a suitable focus to throw a party. Dave (one of the meteorologists), chose an 80's theme for his a fortnight or so ago resulting in attendees from striking miners, through Miami Vice and Button Moon characters to Crocodile Dundee and a Wall Street yuppie.

Dave's 80s Party

The Easter Bank Holiday weekend started with the first winter barbecue of the season. Though it took a good couple of hours to get going in the -30°C weather, Ant's (Z-Chef) skill with everything food related, meant that all was edible, rather than reverting to its previously frozen state that has thwarted barbecues in the past.

The Barbie Gets Going
Ant modeling a BAS-issue warm Canada Goose jacket

The greatest danger at these barbies is of a can of beer freezing to your tongue, for at this temperature metal conducts any heat away from exposed skin, so rapidly that they freeze solid together, to the point where pulling the metal away will simultaneously remove a large chunk of the dermis. Admittedly, it is usually more of a problem when climbing and fiddling with kit without gloves on but fortunately it did not claim any lingual casualties on this occasion, as the recommended remedy when climbing is for a partner to urinate on the affected metal to warm it up.

No Burnt Sausages Here

The concept of a Bank Holiday seems incongruous when the only banking required in this cash poor economy, is for buying beer and wine at the bar, even at that time the transaction is reduced to an honesty tick sheet which produces a (usually) small bill at the end of the month, particularly given that the British Antarctic Territory does not charge duty on alcohol! There can be few other jobs that provide all lodging, toiletries, clothes and food with someone even to cook it. However, a couple of extra days off and some good weather has meant plenty of time outdoors, kiting and cross-country ski-ing.

Kiting By Moonlight
Dean returns home from a kite-boarding session