TY  - JOUR
A1  - Roessiger, Jens
A1  - Bons, Paul D.
A1  - Griera, Albert
A1  - Jessel, Mark W.
A1  - Evans, Lynn
A1  - Montagnat, Maurine
A1  - Kipfstuhl, Sepp
A1  - Faria, Sergio H.
A1  - Weikusat, Ilka
T1  - Competition between grain growth and grain-size reduction in polar ice
Y1  - 2011
VL  - 57
IS  - 205
SP  - 942
EP  - 948
JF  - Journal of Glaciology
DO  - 10.23689/fidgeo-2637
N2  - 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.
UR  - http://resolver.sub.uni-goettingen.de/purl?gldocs-11858/6950
ER  -