DETECTION OF MOUNTAIN PERMAFROST BY COMBINING HIGH RESOLUTION SURFACE AND SUBSURFACE INFORMATION – AN EXAMPLE FROM THE GLATZBACH CATCHMENT, AUSTRIAN ALPS
Otto, J.‐C., Keuschnig, M., Götz, J., Marbach, M. and Schrott, L., 2012. Detection of mountain permafrost by combining high resolution surface and subsurface information – an example from the Glatzbach catchment, Austrian Alps. Geografiska Annaler: Series A, Physical Geography, 94, 43–57.
Permafrost distribution in mid‐latitude mountains is strongly controlled by solar radiation, snow cover and surface characteristics like debris cover. With decreasing elevation these factors have to counterbalance local positive air temperatures in order to enable permafrost conditions. We combine high resolution surface data derived from terrestrial laser scanning with geophysical information on the underground conditions using ground penetrating radar and electrical resistivity tomography and ground surface temperature data in order to understand the effects of surface characteristics on permafrost distribution in an Alpine catchment, Austrian Alps (Glatzbach, 47°2′23.49″ N; 12°42′33.24″ E, 2700–2900 m a.s.l.). Ground ice and permafrost is found above an elevation of 2780 m a.s.l. on north‐east facing slopes in 2009, previous studies detected permafrost at the same site at 2740 m a.s.l. in 1991. Analysis of surface roughness as a proxy for grain size distribution reveals that the lower boundary of discontinuous and sporadic permafrost is lowered on rough surfaces compared to fine‐grain zones. At the same location modelled potential summer solar radiation in coarse grain zones is reduced by up to 40% compared to surfaces of fine grain sizes. The mostly patchy permafrost distribution at the Glatzbach can therefore be attributed to local surface cover characteristics, particularly regolith grain size and its influence on solar radiation. We conclude that the analysis of ground surface characteristics using very high resolution terrain data supports the assessment of permafrost in Alpine areas by identifying rough surface conditions favouring permafrost occurrence.
Document Type: Research Article
Affiliations: Department of Geography and Geology, University of Salzburg, Salzburg, Austria
Publication date: 2012-03-01