Overview

Concerning “Global Climate Change” it is of special importance how far particular properties of extreme events will change during the next decades. Extreme precipitation is a prominent example. For individual regions there might be small-scale varieties, which can only be derived by indirect means from large-scale GCM output (General Circulation Models, grid point distances several hundred km). In that respect, deriving regional precipitation from large-scale GCM data (so-called downscaling) has to be critically assessed, since relationships between regional precipitation (spatial scale of Central Europe or smaller areas) and ‘Großwetterlage’ (i.e. pressure fields on a continental scale) are marked by considerable instationarities.
Consequently and in contrast to that, analysing fronts and convective conditions of regional to local dimensions is the starting point of this project. A fundamental advantage could be that fronts and convective phenomena cover areas comparable in extent to those being affected by resulting precipitation and runoff. Based on that, output of the atmosphere-ocean GCM ECHAM4 (Hamburg) can be used for more consistent estimations of 21st century’s precipitation variability.

Rock moisture is one of the most important determining factors for the intensity and distribution of weathering processes. However, quantitative measurements are scarce, which is partly due to the lack of reliable measurement techniques. In our studies we apply 2D-resistivity profiling adapted to the requirements of small-scale rock / stonework investigation. We use a GeoTom 2D system with individually manufactured shielded cables for 50 electrodes, connected with crocodile clips to an array of screws drilled in rockwalls or, respectively, medical ECG electrodes stuck to built walls to avoid damage. The spacing between electrodes is 4-8 cm depending on the individual wall geometry, leading to total profile length of 2-4 m. Medical ECG electrodes have been found to provide good electrical contact with the wall surface, without causing any damage and to be robust over several days or even weeks. The overall aim of the sampling campaigns is to investigate the variability of moisture contents over space and time and their relation to weathering features observed.

Understanding regional sediment budgets requires the quantification of stored material in sediment sinks. However, our knowledge of talus slope and basin volumes is still fragmentary. Geophysical investigations frequently offer the only opportunity of achieving significant results on debris volume and composition. The aims of the studies were (1) to gain insight into the inner structure of alpine sediment bodies using ground-penetrating radar (GPR) and further geophysical techniques, (2) to provide an estimate of long-term weathering and removal rates by measuring the total volume of debris accumulated on slopes and in basins and (3) to compare these values to short-term measurements of current processes and find reasons for discrepancies.

The aim of this projekt was a detailed investigation to provide data to help quantify in greater detail the spatial and temporal fluctuation of soil water dynamics under the influence of irrigation; the basis were data collected personally between 2003 and 2006. The region selected was South Tyrol in northern Italy: with about 18.000 hectares the biggest coherent apple growing area in Europe. It is generally believed that intensive fruit cultivation there has to rely on regular irrigation of the fruit trees to guarantee optimum results in both quantity and quality of the produce. However, the way irrigation is applied there follows very subjective criteria. The consequence is that irrigation in this region is a very cost-intensive factor of production which is increasingly being discussed and criticized for both economical and ecological reasons. These conditions provided several targets for this project: One was to provide fundamental information and data on the patterns of the regional soil water dynamics under the influence of irrigation as well as parameters of natural influences. These data were then used as a basis from which to evaluate the necessity and the real amount of irrigation needed, based on regional differentiation and objective criteria. A further target was to provide various parameters by collecting a vast number of data taken at hourly intervals and, as a result, to establish transfer models specific to locations and depths that were to describe and explain the soil water dynamics of specified locations and, if possible, locations in general.