HARZ/CENTRAL GERMAN LOWLAND (GERMANY)
OPERATING INSTITUTE: UFZ Helmholtz Centre for Environmental Research Leipzig.
MAIN PURPOSE: Global and climate change effects on terrestrial environmental systems.
ECOSYSTEM TYPE: Grassland, forest, arable land, floodplains, urban areas.
EXPERIMENTAL TREATMENTS: Climate change, land use change.
LOCALISATION: 51.48072623730154 11.9622802734375
FACILITIES: Based on UFZ priority areas in environmental research, water research, soil research, biodiversity research and different social scientific aspects form the central focus of the research programme at the observatory. The effects of changes in climate and land use on biodiversity are being explored at a network of biodiversity observation sites.
A hydrological observatory covering the catchment of the river Bode (3300km²) is devoted to research on the relationship between climate, land use and water balance. Within the observatory main intensive test sites are in place in order to investigate specific hydrological issues and matter fluxes in detail. The infrastructure consists of wire-less soil moisture networks, groundwater monitoring, runoff and water quality monitoring stations, eddy covariance towers (ICOS sites), cosmic ray moisture probes, geophysical monitoring (ERT, GPR, EM), airborne monitoring and lysimeters. In addition, rain radar and additional weather stations were installed in regions that are relevant for modeling studies.
A Critical Zone Observatory, the CZO “Selke”, is an integral part of the observatory and serves research on the interplay between catchment structure and dynamic external forcing and the effects on hydrological dynamics and matter transformation.
A set of MOBICOS (Mobile Aquatic Meso-cosms) - laboratory containers are set up close to water bodies and fed with the “on-site water”, creating a “natural” testing envi-ronment to explore feedbacks between water quality and aquatic ecosystems.
At the GCEF (Global Change Experimental Facility) in Bad Lauchstädt, a large-scale outdoor infrastructure that uses a well-replicated design with large field plots (400m²) allows the simulation of changing climatic and land use conditions and the assessment of ecological systems response.
In the framework of TERENO, “terrestrial observatories” are set up in selected German regions for climate and land use change studies. The Harz/Central German Lowland Observatory is one of these observatories that are equipped with a combination of in situ measuring instruments and ground-based, airborne and satellite-borne remote sensing techniques.
● Kamjunke, N., Büttner, O., Jäger, C.G., Marcus, H., von Tümpling, W., Halbedel, S., Norf, H., Brauns, M., Baborowski, M., Wild, R., Borchardt, D., Weitere, M. 2013. Biogeochemical patterns in a river network along a land use gradient. Environ Monit Assess 2013, doi:10.1007/s10661-013-3247-7.
● Brosinsky, A., Lausch, A., Doktor, D., Salbach, C., Merbach, I., Gwillym-Margianto, S., Pause, M., (2013): Analysis of spectral vegetation signal characteristics as a function of soil moisture conditions using hyperspectral remote sensing. J. Indian Soc. Remote Sens.
TA PROJECTS: Investigating the impacts of deforestation on hydrological and sediment connectivity in the Wüstebach catchment, Germany (LACOCON)
TA User (visit): Ronald Poppl, University of Vienna, Austria (March, 2015 – 05 days)
Project Description: Knowledge on sediment dynamics is fundamental to the understanding of geomorphic and ecologic systems as geomorphic processes can for instance erode valuable soil layers. Entering the fluvial system the transported matter can modify channel morphology and thus influence flow dynamics, habitat evolution and element concentration, or even govern the fate of sediment-associated detrimental pollutants. To current knowledge, those earth surface shaping processes are strongly influenced by climate, underlying lithology, vegetation and human impact (Syvitsky & Milliman 2007). However, we are lacking basic concepts and methodological approaches to untangle the complexity inherent in hydro-geomorphic systems which are related to interactions and feedback processes between landscape compartments and processes involved.
Recently, the role of connectivity in controlling runoff and erosion has received significant and increasing scientific attention (e.g. Parsons et al. 2015, in press). Related to sediment dynamics, sediment connectivity is defined by Hooke (2003, p. 79) as “the potential for a specific [sediment] particle to move through the system”. Connectivity concepts and assessments are increasingly used to describe linkages between sediment source areas and the corresponding sinks within a catchment (Croke et al. 2005) and are therefore an important tool to estimate sediment conveyance and propagation through a system (e.g. Poeppl et al. 2012). Investigating sediment connectivity in geomorphic systems provides an important opportunity to improve our understanding of how physical linkages govern geomorphic processes (Van Oost et al. 2000; Wainwright et al. 2011) and geomorphic responses to change. Given that the sensitivity of a system to change is largely governed by the capacity of its various components to transmit an impulse, an effective assessment of connectivity between these components provides a basis to identify transmission linkages, coupling efficiencies and thus sensitive elements within the system (Brunsden 2001, Brierley et al. 2006).
The main aim of the proposed project is to investigate the impacts of deforestation on hydrological and sediment connectivity in the Wuestebach catchment. Research questions: a) How does deforestation influence hydrological connectivity, sediment pathways and fluxes in the Wuestebach catchment? b) Is gross sediment transport governed by high-magnitude meteorological events, or are small magnitudes equally important? c) How does deforestation influence the river runoff regime and channel morphology? d) How does geomorphic catchment evolution evolve in future?
3-D monitoring of simulated rainfall infiltration in natural soils.
TA User (visit): Alessandro Arato, DIATI - Department of Environment, Land and Infrastructure Engineering, Politecnico di Torino (September, 2014 - 5 days).
Project Description: Infiltration of water from the surface and subsequent redistribution through the unsaturated zone is an important hydrological process, having implications for management of agricultural crops, soil drainage and groundwater recharge. Improved soil moisture management is crucial for sustainable improvement of food production and water supply (FAO, 2003).
Non-invasive characterization of flow and transport phenomena in the unsaturated zone gained importance in geophysical community in the last decades, contributing to the development of a branch also known as hydro-geophysics. More specifically, time-lapse non-invasive electrical resistivity tomography (ERT) has been recently applied to monitor flow and transport phenomena in soils at field and laboratory scale, soil–plant interactions in the root zone and gain a better understanding for modeling exchanges of fluxes in the soil–vegetation–atmosphere system (e.g. Binley et al., 1996, 2002, Garrè et al, 2010).
The integration of hydrological and geophysical measurements in a fully coupled 3D hydro-geophysical inversion seems a useful way forward to feed comprehensive hydrologic modeling tools with a suitable amount of good quality data (Romano, 2014). Moreover, we have a strong background on the application of resistivity tomography to environmental problems, since we worked in the recent years in the integrated characterization of NAPL-contaminated sites (Arato et al., 2013), and developed innovative tools for processing of ERT data to increase the accuracy of the cross-hole tomographic surveys (Arato et. al. 2014).
We aim on testing the suitability of 3D inversion of high resolution electrical measurements at very small field scale for imaging infiltration patways in soils under natural conditions, towards the improved understanding of runoff response to rainfall in soils.
The Schäfertal study site, part of the Harz/Central German Lowland TERENO observatory (Zacharias et al, 2011) is a perfect test site for the proposed method because of the provided infrastructure (wireless soil moisture monitoring, time-lapse EMI measurements) and the resulting detailed knowledge on soil characteristics and soil moisture dynamics.
Simulation of water and snow dynamics at the Schäfertal catchment.
TA User (visit): Marco Bittelli, Department of Agricultural Science, University of Bologna (ITALY) (September, 2014 - 5 days).
Project Description: The purpose of this research is to investigate the dominant hydrological processes at the Schäfertal catchment experimental site and to provide a broad description of the hydrological and environmental variables at the site. Moreover, we will investigate the relationships between the soil water and the soil heat balance, for a better understanding of the processes involved.
Specifically, the different hydrological processes are determined by a variery of processes, including geomorphological features, weather variables and their spatial distribution, soil properties, plant variables, soil management and so forth. Therefore to fully understand the processes taking place at a specific site, it is necessary to employ a broad approach, where all these components are considered. Because of the complexity involved in considering the system as a whole, and because of the non-linearity of many transport processes, a broad experimental and modelling is necessary.
This complex task can be reached by combining detailed experimental measurements and modelling. Our contribution to the current project is the modelling of the hydrological processes at the site. Our research group has developed an hydrological model (called CRITERIA) for multiscale applications. A simple one-dimensional version can be used at the plot scale, then a three-dimensional version can be employed for small catchments and then a regional scale version is available for regional studies. Some information and bibliographical information can be found at the website.
The use of a model developed by the same group involved in the project is a key component for a successful project, since we have the flexibility to modify and write new the code to include additional processes or modify the boundary conditions, depending on the specific site features, as needed.
The project will be developed in close collaboration with the XXXX group, performing the experiment at the site. Specifically, digital elevation data (DEM), weather, soil and plant data will be measured at the site. These data are necessary as input for the model. Moreover, the groundwater table depth will be periodically measured to provide input as time-dependent lower boundary condition of the unsaturated zone.
In addition, this project will include algorithms into the model for computation of coupled heat, liquid water and water vapour transport in the vadose zone. The model will be tested by comparing the output data against soil temperature measurements performed at the site.
The project will enhance the understanding of a complex geo-hydrological system, by investigating the dynamics of a large variety of processes. The combined experimental and modelling effort will allow for identification of the dominant hydrological processes.
Assessing ecosystem function by soil quality with hyperspectral remote sensing.
TA User (visit): Tarin Paz-Kagan, Ben-Gurion University, Israel (May/June, 2013).
Project Description: Hyperspectral remote sensing (HRS) is an advanced technique that provides near-laboratory-quality reflectance spectra of each single pixel. This capability allows the identification of targets based on their well-known spectral absorption features. The spectral information of the visible, near-infrared, and shortwave infrared (VIS-NIR-SWIR; 0.4–2.5 mm) spectral regions provides a promising capability to identify soil, vegetation, rock, and mineral materials. Hyperspectral remote sensing provides very valuable data for environmental research in different scales (laboratory, filed, landscape scale).
Evaluation of ecosystems structure - function is complex and needs an integrated methodology. Using soil quality, net primary productivity, and landscape pattern indicators can help evaluate ecosystems structure-function in landscape scale. Remote sensing applications provide great potential for monitoring indicators of environmental change and ecosystem function. The methodology guideline of this research is to examine the correlations between field indicator measurements and HSR in different scales (laboratory, filed, landscape). Studies with different spatial scales are significantly constrained due to limited data availability and have important value to ecosystems state.
Experiments on spatial and temporal behavior of soil quality indicators primary productivity, and landscape pattern indicators will be performed with hyper spectral images (0.4-2.5 mm) the spectral response of the different parameter will be carried out to logarithmic model. The spatial levels will be implemented by laboratory experiments, lifting platform within field, and airborne field campaigns. The data with different spectral and spatial resolutions should be tested in various ecosystems to understand their potential for estimating the methodological guideline and above-mentioned parameter.