Bubbly-ice densification in ice sheets: II. Applications

Ice sheets and nitrogen.

Snow and ice play their most important role in the nitrogen cycle as a barrier to land-atmosphere and ocean-atmosphere exchanges that would otherwise occur. The inventory of nitrogen compounds in the polar ice sheets is approximately 260 Tg N, dominated by nitrate in the much larger Antarctic ice sheet. Ice cores help to inform us about the natural variability of the nitrogen cycle at global an...

Vanishing Polar Ice Sheets

Global temperatures have increased by 0.8◦C since instrumental records began, and the last decade has been the warmest. This warming has been closely linked to increasing greenhouse gas concentrations due to human activities. Arctic warming is leading to thinning and disappearance of sea ice on the Arctic Ocean and the increased melting of the Greenland ice sheet. In the last decade the Antarct...

Dynamic Recrystallization of Ice in Polar Ice Sheets

The deformation and recrystallization mechanisms which control the viscoplasticity of ice from polar ice sheets have been investigated. The high plastic anisotropy of ice crystals is responsible for the development of a non uniform internal stress field within the polycrystal. Strain-shadows produced by sub-grain are observed in polarized light when the rotation recrystallization regime is domi...

Ice sheets and sea level.

Steady Motion of Ice Sheets

Steady plane flow under gravity of a symmetric ice sheet resting on a horizontal rigid bed, subject to surface accumulation and ablation, basal drainage, and basal sliding according to a shear-tractionvelocity power law, is treated . The surface accumulation is taken to depend on height, and the drainage and sliding coefficient also depend on the height of overlying ice. The ice is described as...