Al, Wednesday 31 December 2008
Scott’s Terra Nova hut has been under threat from the buildup of snow and ice pressing against it. The building was slowly being engulfed by a mini glacier forming behind it.
Using shovels and wheel barrows the Trust’s staff would spend up to a week each summer removing a hundred or more cubic metres of snow. This process was unsustainable and each year the buildup of ice would increase.
With the best intent the Antarctic Heritage Trust was losing the battle with Mother Nature. A simple solution to this complex problem was urgently required.
After consulting with international experts it was decided to use the energy sources provided by nature to resolve the problems created by nature.
The first solution was to increase the rate of ice melt each summer by spreading scoria, dark coloured volcanic gravel on the ice. Snow reflects the solar radiation so it minimises the amount of ice that melts. On the other hand, scoria absorbs solar radiation so it increases the surface temperature of the ice and makes more of it melt. The same thing happens if you put a white object and black object in the sun and then feel the temperature difference between the two – the black one will be warmer because it has absorbed more solar radiation.
The second solution was to create a turbulent air flow to reduce the snow build up behind the hut. This was achieved with the use of vortex generators, aluminum triangles that are free to rotate and point into the wind at an angle of 15 degrees. The turbulence or vortexes created by these structures as the wind passes across them erodes the snow collecting behind the hut.
As I write this blog the ice is slowly melting in the 24 hour sunshine and the wind is eroding the snow.
A great outcome!