But the other 20% which takes place as deformation can be a problem for the drilling because it will affect the tilt of the hole. But Dorthe Dahl-Jensen is confident: “If we assume that the 20% deformation will occur in the lower 500 metres, it will mean that the borehole will get 1° of tilt each year. We can easily handle that over the 5-year period the drilling will take place, especially if we change our 12 metre long drill to a shorter 4 metre drill in the lower part. In fact, we will be able to handle a deformation of up to ten metres, provided of course that it doesn’t happen too much in jerks.”
Pioneering work Dorthe Dahl Jensen speaks of the upcoming drilling as pioneering work because there is currently only a limited knowledge of what is actually happening down in the large ice streams; and when researchers do not understand the processes in the ice streams, they cannot develop good ice flow models either. She is counting on the drilling remedying that because the long core will not only provide new knowledge about the ice crystals and the deformation of the ice, but also about the water channels and the water pressure down at the bottom. In addition to the drilling, they will also be continuously measuring the temperature, the tilt and the pressure in the borehole. “We must use our new knowledge to understand how the ice flows so the data we collect will be fed into our flow models, which will then simulate the ice stream. It will be used to predict what is going to happen in the future and it can be used directly to calculate the rises in sea levels,” concludes Dorthe Dahl Jensen. The drilling does not start until 2016, while the field season this year was being spent moving the equipment from the old NEEM camp on the top of the ice sheet to the new location, which has been named EGRIP. Poul-Erik Philbert
Dorthe Dahl-Jensen, Centre for Ice and Climate, University of Copenhagen