Gravimetric investigations at Vernagtferner, Austria
21/09/2016 | 16:45 | Session 4: Global gravity field modelling
Author(s): Christian Gerlach, Christian Ackermann, Reinhard Falk, Alexander Lotthammer and Andreas Reinhold
Christian Gerlach, Christian Ackermann, Reinhard Falk, Alexander Lotthammer and Andreas Reinhold
The globally observed melting of mountain glaciers is an indicator of local and regional effects of climate change. Loss of glaciers in mountain areas affects the environment on local and regional scales (water supply, thawing of permafrost, local radiation balance, etc.) and still is a main contributor to eustatic sea level rise. There exist various methods to estimate glacier mass balance, i.e., the geodetic, glaciological and meteorologic method. All of them observe different quantities connected to mass balance, e.g., area or volume changes, but they are not directly sensitive to mass. In contrast, gravimetry is directly sensitive to mass variations. Satellite gravimetry has proven to provide valuable complementary information of mass transport on regional to global scales. It is not possible, however, to infer mass balance of individual mountain glaciers from satellite data. The goal of this work is to test terrestrial gravimetry for glaciological applications on local scales. Vernagtferner in the Austrian alps is chosen as test area, because it is one of the best observed mountain glaciers world wide. All different methods have been applied over the years for studying glacier mass balance and estimating glacier thickness. Therefore it is an ideal test field for validating the gravimetric results. Since 2010, relative gravimeters have been used to observe gravity variations on several stations on and around the glacier. In 2014 absolute observations were performed with an A10 absolute gravimeter. Here we present the set up of the observing program and discuss some of the results achieved so far.