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Forschergruppe (FOR) 1598: From Catchments as Organised Systems to Models based on Dynamic Functional Units (CAOS)

Das Projekt "Forschergruppe (FOR) 1598: From Catchments as Organised Systems to Models based on Dynamic Functional Units (CAOS)" wird vom Umweltbundesamt gefördert und von Karlsruher Institut für Technologie (KIT), Institut für Wasser und Gewässerentwicklung, Bereich Hydrologie durchgeführt. Within phase 2 of the CAOS research unit we will work towards a holistic framework to explore how spatial organization alongside with spatial heterogeneity controls terrestrial water and energy cycles in intermediate scale catchments. 'Holistic' means for us to link the 'how' to the 'why' by drawing from generic understanding of landscape formation and biotic controls on processes and structures as well as to rely on exemplary experimental learning in a hypothesis and theory based manner. This also implies treatment of soil, vegetation and atmosphere as coupled system rather than a linear combination of different compartments. To jointly work towards this goal we propose 7 projects which will closely cooperate within two overarching work packages:WP1: Linking hydrological similarity with landscape structure across scalesWP2: Searching for appropriate catchment models and organizing principles. Within WP1 we will further refine the existing stratified multi-method and multi-sensor setup to search for functional entities in the Attert and, if they exist, to learn in an exemplary manner which structural features control functional characteristics. This essentially includes identification of suitable metrics to discriminate functional and structural similarity from data as well as identification of useful quantitative descriptors for the rather fuzzy term 'hydrological function'. Overall we aim to synthesize a protocol to decide 'where to assess which data for what reasons' for characterizing hydrological functioning across a scale range of four orders of magnitude.Within WP2 we will foster our distillery of parsimonious and nevertheless physically consistent model structures which rely on observable quantities and make use of symmetries in the landscape to simplify the governing model equations in a hypothesis based manner. To this end we will compare concurring model structures (among those the CAOS model) and work towards a framework for an objective model inter comparison with special emphasis on a) the added value of different data/information sources and b) on consistency of predictions with respect to distributed dynamics and integral flows. Additionally, we aim in WP2 at linking the 'how' to the 'why' by synthesizing testable hypotheses that could explain whether spatial organization has evolved in accordance with candidate organizing principles. Ecology, fluvial geomorphology and thermodynamics offer a large set of candidate organizing principles for this issue. Based on our recent work we will focus especially on thermodynamic limits and optimality principles like maximum entropy production, explore their value for uncalibrated hydrological predictions and work out the necessary requirements on data and models for testing these principles. We put special emphasis on a possible experimental falsification of these candidate principles; also in close collaboration with the B2-Landscape Evolution Observatory in Tucson, Arizona.

Raum-Zeit Dynamik von Wasserspeicherung,-mischung und -Freisetzung

Das Projekt "Raum-Zeit Dynamik von Wasserspeicherung,-mischung und -Freisetzung" wird vom Umweltbundesamt gefördert und von Universität Freiburg, Institut für Geo- und Umweltnaturwissenschaften, Professur für Hydrologie durchgeführt. Wasserspeicherung, -mischung und -freisetzung zählen zu den Kernfunktionen von Einzugsgebieten. Noch immer ist wenig über den Zusammenhang zwischen Wasserspeicher-Dynamik (räumlich, zeitlich) und Einzugsgebiets-Prozessen bekannt. Dazu werden Daten der ungesättigten und gesättigten Zone von 46 Cluster-Standorten im Attert-Einzugsgebiet in Luxemburg ausgewertet. Zusammen mit bodenphysikalischen Daten und Informationen über Makroporen und Fließpfade (Farbtracer), wird versucht Aussagen über Infiltrationsprozesse zu treffen. Diese sollen in Abhängigkeit der Vorfeuchte und der Niederschlagsintensität charakterisiert und diese Ergebnisse mit einer bodenhydrologischen Kartierung verglichen werden. Mit dem Modell RoGeR (runoff generation research model) werden die hydrologischen Charakteristiken und Abflussbildungsprozesse der Standorte untersucht und die Ergebnisse genutzt, um fehlende relevante Prozesse und Parameter des Systems zu erkennen.

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