Icesheet profiles

The framework outlined in section 57.2 provides the most concise formalism for examining the connections between the phenom-enological description of ice and whole-ice-sheet characteristics. I next use it to evaluate whether our conception of these intermediate-scale properties is explanatory at the continental scale, by comparing solutions to Equations (16) and (27) with icesheet surface-elevation profiles (following the general idea used by Vialov (1958) and especially Haefeli (1961); cf. Hamley et al., 1985). Specifically, I ask which values for S, A* and n yield bestfit matches between calculated profiles and data, whether these matches are good, and whether these parameter values are consistent with expectations.

The three major extant ice sheets are all very different. Although each varies from sector to sector, the following generalizations are most broadly true, and help motivate the choice of a representative elevation profile for each. The Greenland Ice Sheet (GIS) is strong-bedded and relatively narrow, and has a moderate to high accumulation rate, a mostly frozen bed, and a marginal ablation zone where melt rates are high. The East Antarctic Ice Sheet (EAIS) is strong-bedded and broad, has a low accumulation rate and a bed that is thawed in much of its interior, and mostly terminates in small floating ice shelves rather than ablation zones. The West Antarctic Ice Sheet (WAIS) is broad and has a weak-bed, ice-stream-dominated flank but a strong-bedded inner core, a moderate accumulation rate and a thawed bed, and terminates in immense ice shelves.

Was this article helpful?

0 0

Post a comment