From subsurface structures to functions and texture - linking virtual realities and experiments at the plot and hillslope scales
Zusammenfassung der Projektergebnisse
This project explored, within the frame of the CAOS research unit FOR 1598, a new thermodynamic perspective on hydrological dynamics. To this end, we characterized the soil water content by its Gibbs free energy, which jointly reflects gravity and capillary controls. From this, they derived a new system characteristic determining the possible range of energy states of soil water, which is well suited to distinguish the typical interplay of gravity and capillarity controls on soil water dynamics in different landscapes. Moreover, the energy state functions consist of two different regimes associated either with a storage excess or with a storage deficit. We showed that storage dynamics into different landscaped is straightforwardly visualized as distinctly pseudo oscillations of the corresponding free energy state around the local equilibrium. The free energy state of soil water in the riparian zone of both study catchments provides furthermore a theoretically sound explain of the threshold like onset in streamflow generation. Complementary to that a novel thermodynamic index was proposed to explain topographic controls on runoff generation named reduced dissipation per unit length (rDUNE). rDUNE jointly accounts for the energetic driver and the dissipative loss along the flow path and a provided stronger discrimination of catchments into groups of similar runoff generation than HAND or the topographic wetness index (TWI). Moreover, we corroborated the central CAOS hypothesis postulating the existence of functional units of similar hydrological behaviour within two related model studies. The first study corroborated that the water balance of two different mesoscale catchments, the Colpach and the Wollefsbach, can successfully be simulated by a single 2d representative hillslope. In both catchments, the representative models yielded simulations of streamflow, optionally sap flow and distributed soil moisture dynamics in good accordance with observations. This success is explained by the fact that both models preserve the relevant information about the driving gradients and resistance terms that control runoff generation and hydrological dynamics. Furthermore, it was shown by means of the Shannon entropy that simulations by means of a fully distributed setup of the same Colpach catchment using 105 different hillslopes yielded strongly redundant contributions of streamflow, and that the fully distributed model, consisting of 105 hillslopes, could be compressed to a model using six hillslopes with distinctly different runoff responses, without a loss in simulation performance. In both catchments, the representative models yielded simulations of streamflow, optionally sap flow and distributed soil moisture dynamics in good accordance with observations Furthermore, we successfully advanced research activities started within the first funding Phase within Project I ‘From subsurface structures to functions and texture linking virtual realities and experiments at the plot and hillslope scales’. This includes firstly new ways for in-situ imaging of rapid subsurface flow by combining time-lapse ground-penetrating radar with TDR profiling. Secondly, we started to develop Lagrangian models for simulating soil water dynamics and solute transport in structure heterogeneous soils. These studies underpin that Lagrangian models provide many assets to simulate flow and transport in heterogeneous soils compared to the traditional Richards and Advection-Dispersion equations. Overall these findings corroborate that a thermodynamic perspective on hydrological systems offer holistic information for judging and inter-comparing soil water storage and runoff generation as well as new avenues in modeling and upscaling, which cannot be inferred from the traditional water balance thinking alone.
Projektbezogene Publikationen (Auswahl)
- (2016): A Lagrangian model for soil water dynamics during rainfall-driven conditions, Hydrol. Earth Syst. Sci., 20(9), 3511–3526
Zehe, E., and C. Jackisch
(Siehe online unter https://doi.org/10.5194/hess-20-3511-2016) - (2017): Form and function in hillslope hydrology: characterization of subsurface flow based on response observations, Hydrol. Earth Syst. Sci., 21(7), 3727–3748
Angermann, L., C. Jackisch, N. Allroggen, M. Sprenger, E. Zehe, J. Tronicke, M. Weiler, and T. Blume
(Siehe online unter https://doi.org/10.5194/hess-21-3727-2017) - (2017): Form and function in hillslope hydrology: in situ imaging and characterization of flow-relevant structures, Hydrol. Earth Syst. Sci., 21(7), 3749–3775
Jackisch, C., L. Angermann, N. Allroggen, M. Sprenger, T. Blume, J. Tronicke, and E. Zehe
(Siehe online unter https://doi.org/10.5194/hess-21-3749-2017) - (2017): Four-dimensional gridding of time-lapse GPR data, pp. 1–4, IEEE
Allroggen, N., Jackisch C., and Tronicke J.
(Siehe online unter https://doi.org/10.1109/IWAGPR.2017.7996067) - (2017): Picturing and modeling catchments by representative hillslopes, Hydrol. Earth Syst. Sci., 21(2), 1225–1249
Loritz, R., Hassler, S. K., Jackisch, C., Allroggen, N., van Schaik, L., Wienhöfer, J. and Zehe, E.
(Siehe online unter https://doi.org/10.5194/hess-21-1225-2017) - (2017): Unravelling abiotic and biotic controls on the seasonal water balance using data-driven dimensionless diagnostics, Hydrol. Earth Syst. Sci., 21(6), 2817– 2841
Seibert, S. P., C. Jackisch, U. Ehret, L. Pfister, and E. Zehe
(Siehe online unter https://doi.org/10.5194/hess-21-2817-2017) - (2018) ; Impact of Temporal Macropore Dynamics on Infiltration: Field Experiments and Model Simulations. Vadose Zone J, 17:170147
Reck, A., Jackisch, C., Hohenbrink, T. L., Schröder, B., Zangerlé, A., van Schaik, L.
(Siehe online unter https://doi.org/10.2136/vzj2017.08.0147) - (2018): Ecohydrological particle model based on representative domains, Hydrol. Earth Syst. Sci., 22(7), 3639–3662
Jackisch, C. and Zehe, E.
(Siehe online unter https://doi.org/10.5194/hess-22-3639-2018) - (2018): Modeling Subsurface Soil Moisture Based on Hyperspectral Data: First Results of a Multilateral Field Campaign, vol. 37, pp. 34–48, Deutsche Gesellschaft für Photogrammetrie, Fernerkundung und Geoinformation, München
Keller, S., F. M. Riese, N. Allroggen, C. Jackisch, and S. Hinz
- (2018): On the dynamic nature of hydrological similarity, Hydrol. Earth Syst. Sci., 22(7), 3663–3684
Loritz, R., Gupta, H., Jackisch, C., Westhoff, M., Kleidon, A., Ehret, U. and Zehe, E.
(Siehe online unter https://doi.org/10.5194/hess-22-3663-2018) - (2018): Variability of earthworm-induced biopores and their hydrological effectiveness in space and time, Pedobiologia, 71, 8-19
Schneider, A. K., Hohenbrink, T. L., Reck, A., Zangerle, A., Schroder, B., Zehe, E., and van Schaik, L.
(Siehe online unter https://doi.org/10.1016/j.pedobi.2018.09.001) - (2019): A topographic index explaining hydrological similarity by accounting for the joint controls of runoff formation, Hydrol. Earth Syst. Sci., 23(9), 3807–3821
Loritz, R., Kleidon, A., Jackisch, C., Westhoff, M., Ehret, U., Gupta, H. and Zehe, E.
(Siehe online unter https://doi.org/10.5194/hess-23-3807-2019) - (2019): Energy states of soil water – a thermodynamic perspective on soil water dynamics and storage-controlled streamflow generation in different landscapes, Hydrol. Earth Syst. Sci., 23(2), 971–987
Zehe, E., Loritz, R., Jackisch, C., Westhoff, M., Kleidon, A., Blume, T., Hassler, S. K. and Savenije, H. H.
(Siehe online unter https://doi.org/10.5194/hess-23-971-2019) - (2019): How Meaningful are Plot-Scale Observations and Simulations of Preferential Flow for Catchment Models? Vadose Zone Journal, 18(1), 180146
Glaser, B., C. Jackisch, L. Hopp, and J. Klaus
(Siehe online unter https://doi.org/10.2136/vzj2018.08.0146) - (2019): Simulating preferential soil water flow and tracer transport using the Lagrangian Soil Water and Solute Transport Model, Hydrol. Earth Syst. Sci., 23(10), 4249–4267
Sternagel, A., R. Loritz, W. Wilcke, and E. Zehe
(Siehe online unter https://doi.org/10.5194/hess-23-4249-2019) - (2020): Estimates of tree root water uptake from soil moisture profile dynamics, Biogeosciences, 17, 5787-5808
Jackisch, C., Knoblauch, S., Blume, T., Zehe, E., and Hassler, S. K.
(Siehe online unter https://doi.org/10.5194/bg-17-5787-2020) - (2020): Soil moisture: variable in space but redundant in time, Hydrology and Earth System Sciences, 24, 2633-2653
Malicke, M., Hassler, S. K., Blume, T., Weiler, M., and Zehe, E.
(Siehe online unter https://doi.org/10.5194/hess-24-2633-2020) - (2021): Simulation of reactive solute transport in the critical zone: a Lagrangian model for transient flow and preferential transport, Hydrology and Earth System Sciences, 25, 1483-1508
Sternagel, A., Loritz, R., Klaus, J., Berkowitz, B., and Zehe, E.
(Siehe online unter https://doi.org/10.5194/hess-25-1483-2021)
