%0 Journal article
%A Roessiger, Jens
%A Bons, Paul D.
%A Griera, Albert
%A Jessel, Mark W.
%A Evans, Lynn
%A Montagnat, Maurine
%A Kipfstuhl, Sepp
%A Faria, Sergio H.
%A Weikusat, Ilka
%T Competition between grain growth and grain-size reduction in polar ice
%R 10.23689/fidgeo-2637
%J Journal of Glaciology
%V 57
%N 205

%X Static (or ‘normal’) grain growth, i.e. grain boundary migration driven solely by grain boundary energy, is considered to be an important process in polar ice. Many ice-core studies report a continual increase in average grain size with depth in the upper hundreds of metres of ice sheets, while at deeper levels grain size appears to reach a steady state as a consequence of a balance between grain growth and grain-size reduction by dynamic recrystallization. The growth factor k in the normal grain growth law is important for any process where grain growth plays a role, and it is normally assumed to be a temperature-dependent material property. Here we show, using numerical simulations with the program Elle, that the factor k also incorporates the effect of the microstructure on grain growth. For example, a change in grain-size distribution from normal to log-normal in a thin section is found to correspond to an increase in k by a factor of 3.5.
%U http://resolver.sub.uni-goettingen.de/purl?gldocs-11858/6950
%~  FID GEO-LEO e-docs