In frame of this diploma thesis a series of Ground Penetrating Radar (GPR) surveys at the summit of Hoher Sonnblick were conducted. The objective was to determine the internal structures and distribution of mountain permafrost and associated changes due to seasonal variations in temperature. 3D GPR surveys organised by the Geophysics Research group of the TU Vienna, were repeated between 2015 and 2017 at different times, as GPR has successfully been applied to delineate frozen materials in permafrost regions. Nevertheless, in comparison with previous studies, GPR investigations aimed not only at the identification of possible interfaces, but to develop a methodology for the modelling of electrical properties of the subsurface that permits an improved understanding and interpretation of GPR and Electrical Resistivity Tomography (ERT) imaging results. Besides the processing and interpretation of the raw data, a quasi-continues model of the electrical properties in the subsurface at the summit of Hoher Sonnblick was obtained, regarding lithological contacts and discontinuities (e.g., fractures) controlling atmospheric-subsurface interactions. The modelling approach was tested on three case studies in porous and unconsolidated media and finally it was applied in the highly fractured media present at the Hoher Sonnblick. For validation, the GPR modelling results were compared to borehole temperature data revealing consistency.