Geomorphic influence on small glacier response to post-Little Ice Age climate warming: Julian Alps, Europe

摘要

The evolution of glaciers and ice patches, as well as the equilibrium-line altitude (ELA) since the Little Ice Age (LIA) maximum were investigated in the Julian Alps (south-eastern European Alps) including ice masses that were previously unreported. Twenty-three permanent firn and ice bodies have been recognized in the 1853 km(2) of this alpine sector, covering a total area in 2012 of 0.385 km(2), about one-fifth of the area covered during the LIA (2.350 km(2)). These features were classified as very small glaciers, glacierets or ice patches, with major contribution to the mass balance from avalanches and wind-blown snow. Localized snow accumulation is also enhanced in the area due to the irregular karst topography. The ice masses in the region are at the lowest elevations of any glaciers in the Alpine Chain, and are characterized by low dynamics. The ELAs of the two major LIA glaciers (Canin and Triglav) have been established at 2275 +/- 10m and 2486 +/- 10m, respectively, by considering the reconstructed area and digital elevation model (DEM) and using an accumulation area ratio (AAR) of 0.44 +/- 0.07, typical of small cirque glaciers. Changes in the ELA and glaciers extension indicate a decoupling from climate. This is most evident in the smallest avalanche-dominated ice bodies, which are currently controlled mainly by precipitation. The damming effect of moraine ridges and pronival ramparts at the snout of small ice bodies in the Julian Alps represents a further geomorphological control on the evolution of such ice masses, which seem to be resilient to recent climate warming instead of rapidly disappearing as should be expected. Copyright (C) 2016 John Wiley & Sons, Ltd.