High-Resolution Virtual Catchment Simulations of the Subsurface-Land Surface-Atmosphere System
Bernd Schalge1, Jehan Rihani2, Gabriele Baroni3,4, Daniel Erdal5, Gernot Geppert6, Vincent Haefliger1, Barbara Haese7, Pablo Saavedra1, Insa Neuweiler8, Harrie-Jan Hendricks Franssen9,11, Felix Ament6, Sabine Attinger3, Olaf A. Cirpka5, Stefan Kollet9,11, Harald Kunstmann7,10, Harry Vereecken9,11, and Clemens Simmer11University of Bonn, Meteorological Insititute, Bonn, Germany 2University of Cologne, Mathematical Institute, Cologne, Germany 3Helmholtz-Center for Environmental Research, Leipzig, Germany 4University of Potsdam, Institute of Earth and Envirenmental Science, Potsdam, Germany 5University of Tuebingen, Center for Applied Geoscience, Tuebingen, Germany 6University of Hamburg, Meteorological Insititute, Hamburg, Germany 7University of Augsburg, Institut fuer Geographie, Augsburg, Germany 8Leibniz University Hannover, Institut fuer Stroemungsmechanik und Umweltphysik im Bauwesen, Hannover, Germany 9Forschungszentrum Juelich GmbH, Agrosphere (IBG-3), Juelich, Germany 10Karlsruhe Institute of Technology (KIT), Institute of Meteorology and Climate Research (IMK-IFU), Garmish-Partenkirchen, Germany 11Centre for High-Performance Scientific Computing (HPSC-TerrSys), Geoverbund ABC/J, Juelich, Germany
Received: 24 Oct 2016 – Accepted for review: 25 Oct 2016 – Discussion started: 01 Nov 2016
Abstract. Combining numerical models, which simulate water and energy fluxes in the subsurface-land surface-atmosphere system in a physically consistent way, becomes increasingly important to understand and study fluxes at compartmental boundaries and interdependencies of states across these boundaries. Complete state evolutions generated by such models, when run at highest possible resolutions while incorporating as many processes as attainable, may be regarded as a proxy of the real world – a virtual reality – which can be used to test hypotheses on functioning of the coupled terrestrial system and may serve as source for virtual measurements to develop data-assimilation methods. Such simulation systems, however, face severe problems caused by the vastly different scales of the processes acting in the compartments of the terrestrial system. The present study is motivated by the development of cross-compartmental data-assimilation methods, which face the difficulty of data scarcity in the subsurface when applied to real data. With appropriate and realistic measurement operators, the virtual reality not only allows taking virtual observations in any part of the terrestrial system at any density, thus overcoming data-scarcity problems of real-world applications, but also provides full information about true states and parameters aimed to be reconstructed from the measurements by data assimilation. In the present study, we have used the Terrestrial Systems Modeling Platform TerrSysMP, which couples the meteorological model COSMO, the land-surface model CLM, and the subsurface model ParFlow, to set up the virtual reality for a regional terrestrial system roughly oriented at the Neckar catchment in southwest Germany. We find that the virtual reality is in many aspects quite close to real observations of the catchment concerning, e.g., atmospheric boundary-layer height, precipitation, and runoff. But also discrepancies become apparent both in the ability of such models to correctly simulate some processes – which still need improvement – and the realism of the results of some observation operators like the SMOS and SMAP sensors, when faced with model states. In a succeeding step, we will use the virtual reality to generate observations in all compartments of the system for coupled data assimilation. The data assimilation will rely on a coarsened and simplified version of the model system.
Schalge, B., Rihani, J., Baroni, G., Erdal, D., Geppert, G., Haefliger, V., Haese, B., Saavedra, P., Neuweiler, I., Hendricks Franssen, H.-J., Ament, F., Attinger, S., Cirpka, O. A., Kollet, S., Kunstmann, H., Vereecken, H., and Simmer, C.: High-Resolution Virtual Catchment Simulations of the Subsurface-Land Surface-Atmosphere System, Hydrol. Earth Syst. Sci. Discuss., doi:10.5194/hess-2016-557, 2016.