Two dipole tracer experiments were performed in a fractured rock at the Grimsel Test Site in February/March 1993. In both experiments NaCl was used as a tracer. The extraction rate was twice the injection rate. In the second experiment injection and extraction were interchanged (Reverse-Experiment). Long tailing was characteristic of the breakthrough curves in both experiments. The tests were interpreted using a single facture allowing for diffusion into an immobile matrix. We were able to interpet the breakthrough curves for both experiments by one unique set of parameters, describing transport and baseflow. Uniqueness could only be achieved when using the information of both experiments. We conclude that performing a Reverse-Experiment is an indispensable tool for parameter identification in dipole tracer tests. A sensitivity analysis proved that not only matrix diffusion is responsible for the tailing in the breakthrough curves but also transversal dispersivity. Further, the typical exchange time between mobile and immobile media was too small to be attributed to matrix diffusion in the strict sense which will causetailing even at large spatial and temporal scales. Analysis of the covariance matrices showed that the parameters have small errors but high correlation. Methods and techniques used: Glaerkin-Finite-Elemente Method, Newton-Raphson, Levenberg-Marquardt, Preconditioned Conjugate Gradient Method, Maximum-Likelihood-Theorie, Confidence Ellipses.
Die Publikation gibt einen vertieften Einblick in die Ergebnisse der Treibhausgas-Projektionsdaten 2025, erläutert die Instrumentenbewertung und veröffentlicht die Daten für das Mit-Weiteren-Maßnahmen-Szenario. Die Projektionen zeigen eine kumulierte Unterschreitung der zulässigen Jahresemissionsgesamtmenge zwischen 2021 und 2030 mit geringen Unterschieden zwischen dem Mit-Maßnahmen- Szenario und dem Mit-Weiteren-Maßnahmen-Szenario. Die Darstellung der Ergebnisse erfolgt gemäß dem Zuschnitt der Sektoren des Bundes-Klimaschutzgesetzes (Energiewirtschaft, Industrie, Gebäude, Verkehr, Landwirtschaft, Landnutzung, LULUCF sowie Abfallwirtschaft und Sonstiges) sowie gemäß der EU-Klimaschutzverordnung (ESR). Darüber hinaus sind detaillierte Sensitivitätsanalysen Teil des Berichtes. Veröffentlicht in Treibhausgas-Projektionen für Deutschland.
We apply for a NanoSIMS 50L ion microprobe instrument for the analysis of soil biogeochemical properties. The specific features of the novel NanoSIMS 50L microprobe technology with the simultaneous analysis of up to seven ion species with high sensitivity and resolution make it an unprecedented tool for the analysis of biogeochemical processes and properties of soils and thereby will boost our ability to locate the association of elements/isotopes in soil structural components at the submicron scale, especially in combination with well-established labelling techniques. NanoSIMS will thus help to unravel the heterogeneous composition and three-dimensional architecture of submicron sized organo-mineral associations in soils. Our research will first focus on the simultaneous analysis of the spatial distribution of C, N, Si and Fe in organo-mineral associations and in a second step be applied to labelling studies: This unique combination provides one of the most promising approaches for exploring the C and N cycle of soils at a resolution not possible before. The NanoSIMS technique introduces new scales to combined multielement and isotope measurements at the submicron scale and thus will allow a major step forward in the understanding of soil formation, with significant implications for our concepts of the soil C and N cycle, soil structural stability, and the sorptive properties of the soil interface.
In the last decades agricultural policy has gained increasingly in complexity. Nowadays it influences the food and agricultural sector from the global market down to the farm level. Widespread research questions, like the impact of the WTO negotiations on the farm structure, most often require comprehensive modeling frameworks. Thus, different types of models are utilized according to their comparative advantages and combined in a strategically useful way to more accurately represent micro and macro aspects of the food and agricultural sector. Consequently, in recent years we have seen an increase in the development and application of model linkages. Given this background, the overall objective of this subproject is a systematic sensitivity analysis of model linkages that gradually involves more and more characteristics of the linkage and the corresponding transfer of results between models. In addition, the project aims to answer the following specific question: How does structural change at the farm level influence aggregate supply and technical progress? Under which conditions is it possible to derive macro-relationships from micro-relationships? How does the aggregation level influence the model results and how can possible problems be overcome? This procedure is used to quantify the effects and to derive conditions for optimal interaction of the connected models. The analysis is based on the general equilibrium model GTAP (Global Trade Analysis Project) and the farm group model FARMIS (Farm Modelling Information System) which are employed in conjunction to analyze the effects of WTO negotiations on the farm level.