An empirical relation between overburden pressure and firn densityAnnals of Glaciology, Vol. 20, p. 87-94, 1994
T. Kameda and H. Shoji
Kitami Institute of Technology, Koencho 165, Kitami, Hokkaido 090, Japan.
Department of Earth Sciences, Toyama University, Gofuku 3190, Toyama 930, Japan.
National Institute of Polar Research, Itabashi, Tokyo 173, Japan.
Geofysisk Afdeling, Niels Bohr Instituttet for Astronomi, Fysik og Geofysik, Københavns Universitet
Two empirical equations for firn densification have been obtained, considering firn porosity as a function of overburden pressure. In the first equation, the reduction ratio of porosity in firn is assumed to be proportional to the increasing ratio of overburden pressure and the mth power of the porosity. The porosity exponent m should be close to -2, so as to have a best-fit with 14 depth-density profiles from Greenland and Antarctica. In the second equation, the reduction ratio of porosity was assumed to increase proportionally to the increment of overburden pressure and the nth power of the porosity. The most satisfactory values of the exponent range from -1 to 1. It has been suggested that firn density, determined primarily by overburden pressure and firn temperature, contribute to a lesser degree.