Permafrost Analysis for the Alpine Monitoring Station at Zugspitze (Bavaria, Germany): Measurements, Modeling and Climate Impacts

Abstract

Abstract Permafrost degradation due to global warming, particularly in mountainous regions, can be responsible for an increase in mass movements such as rockfalls, slides and subsidence. Therefore, preventive measures, based on a simulation of permafrost degradation, should be planned in advance. Consequently, modeling of permafrost in the high Alpine region of Bavaria is the main objective of this study. At first, this paper evaluates a permafrost temperature (T) database for the Permafrost Monitoring Station (PMS), located between 2,922 and 2,907 m a.s.l. at the ridge of the highest mountain of the Bavarian Alps (Zugspitze, 2,962 m a.s.l.). The compiled T data along the oblique (20°) 44.5 m long borehole reveals a warming trend over the period from 2010 to 2020, resulting in a noticeable permafrost degradation. After that, a transient permafrost model was developed and calibrated using collected T records. Then, the model was applied to PMS meteorological data from 1900 to 2015. The permafrost simulations showed a considerable decrease in permafrost along the borehole by the length of about 9.5 m, mainly at the southern side. Lastly, calculation of potential permafrost changes, up to 2100, was performed for two different climate scenarios (RCP8.5 and RCP2.6) with 13 different climate realizations (model runs), obtained from the statistical regional climate model WETTREG2013. The RCP8.5 scenario (9 realizations) is based on the assumption of a linear increase of CO2 emissions with time. The RCP2.6 scenario (4 realizations) assumes no further increase in CO2 emissions. In conclusion, the modeling results for the RCP8.5 scenario imply a permafrost disappearance at the Zugspitze by the end of the 21st century. Yet, in the case of the RCP2.6 scenario, today’s permafrost will remain essentially unchanged.