Water and ion movement through a minicatchment at Risdalsheia, Norway (RAIN project)

At Risdalsheia (Southernmost Norway) the relation between flow paths and streamwater chemistry through a small headwater catchment was investigated. The importance of these pathways for the interaction between soil solution and runoff chemistry was investigated by a tracer experiment with LiBr. The experiment was designed using all available information about ion transport at EGIL-catchment in a simple model that predicted the breakthrough curve for a given tracer input. The unique facility of a roofed catchment allowed attainment and maintainace of a hydrological steady-state under highflow conditions during this tracer experiment. The chemical changes of the moving soil water due to soil/soil solution interaction mainly occured during vertical (unsaturated) infiltration. Most ions reached their runoff concentration levels after these few cm of vertical infiltration. Only the ions SO4, NO3, and H increased along the saturated lateral flow path. Subsurface, translatory flow and equilibrum reactions along vertical infiltration flow paths are the key process that explain the behavior of stormflow chemistry at the EGIL-catchment.Norsk Hydrologisk komite (NHK

Berechnung der Sickerwassermenge unter Wald

This report describes the soil water budget of two beech forests and two clearings in the forest distict of Essen (West Germany). A physical model of water movement in soil was used to calculate monthly sums of the seepage water that leaves the root zone. This information is essential for the evaluation of the ion budgets at these sites. The simple model of water flow through a forest ecosystem is calibrated against measurements of soil water potential over depht and time. The report exemplifies how such models can help to reduce the experimental effort within studies that aim at the water and ion budget of forests.SILVA Økologische Gutachten und Umweltanalytik Gmbh, am Pappelberg 10. D-3401 Ebergøtze

Reversibility of acidification: Soils and surface waters

Recent declining levels of acid deposition in both North America and Europe have initiated reversal of acidification and recovery of impacted ecosystems. The reversibility of acidification has also been investigated by means of large-scale experiments with whole ecosystems. Predictive models can account for much of this empirical and experimental data, at least at coarse spatial and temporal scales. Discrepancies between observed and predicted effects are due in part to the increasingly important role of nitrogen in soil and water acidification. "Nitrogen saturation" threatens to offset the incipient recovery due to reductions in SO2 emissions. Possible ecosystem impacts of future climate change add further uncertainty to predictions of long-term acidifications trends

Recurrence analysis of Eddy covariance fluxes

Measuring energy and matter fluxes between the atmosphere and vegetation using the Eddy Covariance (EC) technique is the state-of-the-art method to quantify carbon exchange between terrestrial ecosystems and their surrounding. The EC equipment is usually mounted onto a flux tower reaching higher than the local canopy. Today, more than 600 flux towers are in operation worldwide. The methodological requirements lead to high sampling frequency (20 Hz) and thus to the production of very long time series. These are related to temperature, wind components, water vapour, heat and gas exchange, and others. In this chapter, the potential of Recurrence Analysis (RA) to investigate the dynamics of this atmosphere-vegetation boundary system is elucidated. In particular, the effect of temporal resolution, the identification of periods particular suitable for reliable EC flux calculations, and the detection of transitions between dynamical regimes will be highlighted

Ordinal pattern and statistical complexity analysis of daily stream flow time series

When calculating the Bandt and Pompe ordinal pattern distribution from given time series at depth D, some of the D! patterns might not appear. This could be a pure finite size effect (missing patterns) or due to dynamical properties of the observed system (forbidden patterns). For pure noise, no forbidden patterns occur, contrary to deterministic chaotic maps. We investigate long time series of river runoff for missing patterns and calculate two global properties of their pattern distributions: the Permutation Entropy and the Permutation Statistical Complexity. This is compared to purely stochastic but long-range correlated processes, the k-noise (noise with power spectrum f−k), where k is a parameter determining the strength of the correlations. Although these processes closely resemble runoff series in their correlation behavior, the ordinal pattern statistics reveals qualitative differences, which can be phrased in terms of missing patterns behavior or the temporal asymmetry of the observed series. For the latter, an index is developed in the paper, which may be used to quantify the asymmetry of natural processes as opposed to artificially generated data.Fil: Lange, H.. Norwegian Forest and Landscape Institute; NoruegaFil: Rosso, Osvaldo Aníbal. Universidade Federal de Alagoas; Brasil. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Computación. Laboratorio de Sistemas Complejos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Hauhs, M.. University of Bayreuth; Alemani

Einfluss der Deposition von Luftschadstoffen auf Oberflaechen- und Grundwasser in einem ausgesuchten Waldoekosystem der Langen Bramke/Oberharz (Zustand und Prognose)

SIGLEAvailable from TIB Hannover: RN 8908(91-045) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman