Polar Radar for Ice Sheet Measurements

Special Report: More Questions And Answers

Do you stay on the ship when you come into various stations, or is there space for you to stay at Davis?
In his role as Deputy Voyage Leader (DVL) Gordon normally stays with the ship for the whole time but can usually get to go ashore for a little while. The Voyage Leader (VL) is normally based at the station for the whole time. One or other of the DVL and VL MUST be on the ship at all times - to be able to deal with anything which might arise. The person ashore does the closer liaison with the Station Leader and others on shore. The person on the ship handles cargo and associated arrangements and any liaison necessary with the Master of the ship and crew. Gordon and the Voyage Leader, Suzanne, talk on the radio quite a lot to sort out arrangements and will work out things if Gordon needs to go ashore. Gordon will probably go ashore on Friday and if he wants to stay over he will have a bed on the station - there is one reserved already. Gordon says he will probably not stay overnight but come back to the ship in the evening.

Is there a certain order that you follow each year as far as which stations are visited in which order?
Each year we have three specific things to do at each station – resupplying the station (bringing in all the supplies they need), changing over the overwintering personnel, deploying and recovering summer personnel. The detail schedule for each year is normally worked out a year or two ahead against a broader trategic plan drawn up many years ahead. It is a complex business planning an itinerary for a season - there are just so many variables - where particular programs are to be run, how many people are required in each area, the number of days of ship charter time we can afford, the availability of watercraft and helicopters, and many other factors. The science strategic plan may also include a major cruise which does most of its scientific work at sea and the nature of that science dictates where the ship goes and for how long. Access to the stations also varies according to historical patterns of the extent and thickness of sea ice.

Timing of the major resupply varies from station to station but generally the same pattern applies at each station from year to year. At Davis for example we prefer to do the resupply in the spring time - this is when the fast ice near the station is very strong and consistent and as this ship has the strength to break through the sea ice here and get to within a few kilometres of the station. At Davis the ship is ‘parked’ firm up against the fast ice and vehicles can drive right up to the side of the ship and take on or deliver cargo using the ship’s crane.

The ice alongside the ship at this time of the year is about 1.7metres thick usually with a layer of about 25cm of snow on top. This is strong enough to land quite a large plane on, for example a C130 Hercules!!! It is certainly strong enough to drive large vehicles on - skidders and loaders and bulldozers and big trucks - there is absolutely no danger walking on it. The only parts which can be dangerous are immediately next to and toward the back of the ship - the engines keep working and the propeller at the back keeps circulating the water so it does not freeze up against the stern and stop the propellers and rudder from working - because then we would be in trouble. The other danger area is where the fast ice is up against the shore or an island. This is where the tide cracks are and the ice may not be very strong. Tide cracks? Just because the ocean surface is frozen doesn’t mean we don’t have tides. The whole ice sheet in fact rises and falls in the same tidal pattern as anywhere else in the world’s oceans. It is where the rising and falling of the sea ice next to the fixed land mass causes the edge to break and split.

At Mawson the situation is very different - they have an excellent harbour and provided the sea ice has ‘broken out’ the ship can go right into the harbour and the cargo only has to travel about 200metres to the station - barges are used to carry the cargo from the ship to the shore where cranes lift the cargo onto trucks on the shore. But at Mawson the sea ice generally does not break out till the latter part of January or toward mid February - in the late summer - so that is when resupply takes place. At Casey it is a bit like Mawson but the harbour access is not as good but resupply is still best undertaken in the summer when the sea ice has broken out. At Macquarie Island there is no ice problem and resupply is traditionally carried out in the late spring or early summer - it is also a watercraft exercise.
The changeover of wintering crew is generally not done at the same time as the resupply nowadays - each operation is complex and deserves undivided attention. To a large extent changeover occurs close to the same time for all stations and this is dictated by the period of training and preparation people need to do to get ready for their expeditions. Changeover generally occurs toward the end of spring/early summer.

The third element is the deployment and recovery of summer people. This is largely dictated by decisions very early on as to how long people need to be at stations to do their work and which part of the season is the best for it. For example people who might need to take ice core samples from lakes need to be there before the ice on the lakes gets too soft or melts - their trip might thus be a short one at the beginning of the season. For people doing a major study of glaciers they might not be able to get to the location till mid season but will remain till the very end. People studying penguins might need to be there just before the start of the breeding season but remain till the time the chicks have been born and have become healthy juveniles.

How many times are these bases visited in all each year?
We try and get to visit each station at least twice in a season, often three or more times, but it does vary year to year. In this season 2000/2001 the overall program provides that we use two ships (the other one is the Polar Bird). Between the two ships we will visit Davis and Mawson four times each, Macquarie Island and Casey twice each and Heard Island four times. You can find more about the Australian Antarcic Program by going to the website, http://www.aad.gov.au/

Well, that it for now. I look forward to more questions so I can share this experience with you all.