Reports on Current Work Temperatures in the Devon Island Ice Cap, Arctic Canada

Abstract

Temperatures have been measured in a 299 m bore hole that reaches the base of the ice near the divide of the main ice cap on Devon Island in the Canadian Arctic Archipelago. Temperature ranges from — 23.0°C at a depth of 20 m to — 18.4°C at the bottom. The difference between surface and bottom temperatures is about 1.5 deg less than expected for a steady state. Recent climatic warming seems the most likely explanation of the discrepancy. The temperature gradient in the lowest 50 m is approximately linear and corresponds to a geothermal heal flux of 1.5 h.f.u. This value may be invalid, however, because temperatures at and below this depth have probably been perturbed by changes of surface temperature during the past several thousand years, particularly by the warming at the end of the last glaciation. A detailed analysis of the results is in progress.

Discussion

W. F. Budd: Do you have any measurements for control of elevation change with time (or balance) to be able to separate climatic temperature changes from changes due to the ice-cap elevation variation?

W. S. B. Paterson: By comparing the decrease in length of the bore hole in one year with the annual mass balance (10 year average) I conclude that the ice cap, at the drill site, is thickening slightly at present. However, I do not know for how long this thickening has been taking place.