Louis Reynaud

Space and Time Distribution of Glacier Mass-Balance in the Northern Hemisphere

Long mass-balance series are compared within four areas of the Northern Hemisphere (The Alps, Scandinavia, the Tien Shan in the Soviet Union, and western North America), using Lliboutrys linear model. This model separates the mass-balance into two main additive terms, one of them depending on time only, and the other one being characteristic of the glacier situation. This study shows that for each mountain range the same type of spatio-temporal distribution pattern for the mass balance can be found that classifies the glaciers according to their distance from the main humidity source. Beyond the mountain range scale, this pattern can no longer be recognized. Available reconstructed mass-balance series for the century are then used. They show that secular trends compare well within Europe and the USSR, but not beyond the continent.

Bilans de masse des glaciers alpins et scandinaves, leurs relations avec l'oscillation du climat de l'Atlantique nord

This paper considers the relations between the North Atlantic Oscillation, reflecting the climate variation patterns on the North Atlantic region, and mass balance variations of Alpine and Scandinavian glaciers. This study first enhances the mass balance representativeness of climate variations on the massif scale. However, dealing with glaciers in the North and the South of Europe, the mass balance variations are inversely correlated. Analyses comparing the mass balance variations and the NAO index show that annual trends between these two components are really poor, but at the decadal scale, the two signals are well correlated.

Greenland ice-sheet mass-balance distribution: a variance analysis of existing field data

A large number of mass-balance measurements have been carried out on the Greenland ice sheet, but few of the series obtained are well suited for statistical studies. Rather than looking at the global mass-balance value, this paper deals with the spatial and temporal mass-balance variability on the ice sheet. Two sorts of analysis are possible: direct comparisons of the series measured at a given site, or a broader approach involving comparisons between different sites using variance analysis. For glaciers in the southwest ablation area, a significant interannual variability (around 1.0 m w.e.) is found. This variability is spatially consistent. In the accumulation area, the results are more complex. For example, there is consistent evidence of year-to-year variations on the west-east Expeditions Glaciologiques Internationales au Groenland (EGIG) profile, but other closer sites are weakly correlated. These results emphasize the need for a better coverage of measurements over the entire ice sheet, as well as longer and more continuous measurement series.