This thesis deals with two issues related to katabatic wind on a melting, mid-latitude glacier, firstly the structure and erosion mechanisms and secondly the along-flow line temperature distribution. Eight weather stations, partly with turbulence measurements on two levels, were installed in the middle and lower part of Hintereisferner, Austria for 3 weeks in August 2018.
The temperature data was compared against a linear lapse rate approach and a physical-based along-flow line model. The latter model, known as modified Greuell-Böhm (ModGB), accounts for katabatic cooling and heating at the glacier tongue. In contrast to previous findings, lapse rate described on-glacier temperature better than ModGB. However, under warm ambient temperatures and at high elevations, differences between ModGB and lapse rate were large. On-glacier air temperature was not measured at high elevations, so the performance of lapse rate and ModGB cannot be definitively determined. Nevertheless, there are indications that ModGB is better suited than lapse rate to describe temperature over the entire glacier.
Spatial and temporal evolution of the location of maximum wind speed (jet height), is studied using a Prandtl model with varying eddy diffusivity and the approximate location of zero vertical momentum or heat flux. Despite limited data and high model uncertainty, results show that katabatic wind deepens and speeds up down-glacier. Erosion of katabatic wind by synoptic or valley wind, cold fronts and rain events is studied concerning ambient weather station data. Cold front passages and rain events caused erosion of katabatic wind on a wide temporal scale from minutes to hours or days in the case of one cold front. Katabatic wind re-established during or shortly after the rain events. The katabatic wind was observed under a large variety of strengths and directions of synoptic or valley flow. Erosion of katabatic wind occurred especially during (strong) orthogonal flow and synoptic flow, very likely Föhn, superimposed with katabatic wind. Despite clear interactions of the two wind systems, a threshold for synoptic wind speed to distinguish pure and influenced katabatic flow was not found. The effect of Föhn or other meteorological events on temperature distribution on a high temporal resolution would be an interesting field of further research and could be linked to ModGB and lapse rate.