Comparison between measured and theoretical temperature profiles of the Camp Century, Greenland, borehole

Steady-state temperature profiles are calculated for the borehole drilled through the Greenland ice sheet at Camp Century. The profiles are found by modifying Robin's theory through the addition of several correction terms. One of these terms is the internal heating arising from creep deformation. The importance of this term was emphasized by Lliboutry. The new theoretical profiles do not differ appreciably from the profile derived from Robin's theory. The theoretical profiles do differ substantially from the Camp Century profile measured by Hansen. It is concluded that Hansen's observations are evidence that factors such as accumulation rate and the upper surface temperature are not in a long-term steady-state condition. Better agreement between theoretical and measured curves is obtained if it is assumed that the accumulation rate was about 40% smaller in the past and that the mean annual surface temperature varied by about 0.5C over the past 1000 years. (Author).