TY  - JOUR
A1  - Merz, Bruno
A1  - Aerts, Jeroen C. J. H.
A1  - Arnbjerg-Nielsen, Karsten
A1  - Baldi, M.
A1  - Becker, Andrew C.
A1  - Bichet, A.
A1  - Bloeschl, G.
A1  - Bouwer, Laurens M.
A1  - Brauer, Achim
A1  - Cioffi, F.
A1  - Delgado, Jose Miguel Martins
A1  - Gocht, M.
A1  - Guzzetti, F.
A1  - Harrigan, S.
A1  - Hirschboeck, K.
A1  - Kilsby, C.
A1  - Kron, W.
A1  - Kwon, H. -H.
A1  - Lall, U.
A1  - Merz, R.
A1  - Nissen, K.
A1  - Salvatti, P.
A1  - Swierczynski, Tina
A1  - Ulbrich, U.
A1  - Viglione, A.
A1  - Ward, P. J.
A1  - Weiler, M.
A1  - Wilhelm, B.
A1  - Nied, Manuela
T1  - Floods and climate: emerging perspectives for flood risk assessment and management
JF  - Natural hazards and earth system sciences
N2  - Flood estimation and flood management have traditionally been the domain of hydrologists, water resources engineers and statisticians, and disciplinary approaches abound. Dominant views have been shaped; one example is the catchment perspective: floods are formed and influenced by the interaction of local, catchment-specific characteristics, such as meteorology, topography and geology. These traditional views have been beneficial, but they have a narrow framing. In this paper we contrast traditional views with broader perspectives that are emerging from an improved understanding of the climatic context of floods. We come to the following conclusions: (1) extending the traditional system boundaries (local catchment, recent decades, hydrological/hydraulic processes) opens up exciting possibilities for better understanding and improved tools for flood risk assessment and management. (2) Statistical approaches in flood estimation need to be complemented by the search for the causal mechanisms and dominant processes in the atmosphere, catchment and river system that leave their fingerprints on flood characteristics. (3) Natural climate variability leads to time-varying flood characteristics, and this variation may be partially quantifiable and predictable, with the perspective of dynamic, climate-informed flood risk management. (4) Efforts are needed to fully account for factors that contribute to changes in all three risk components (hazard, exposure, vulnerability) and to better understand the interactions between society and floods. (5) Given the global scale and societal importance, we call for the organization of an international multidisciplinary collaboration and data-sharing initiative to further understand the links between climate and flooding and to advance flood research.
Y1  - 2014
U6  - https://doi.org/10.5194/nhess-14-1921-2014
SN  - 1561-8633
VL  - 14
IS  - 7
SP  - 1921
EP  - 1942
PB  - Copernicus
CY  - Göttingen
ER  - 
TY  - JOUR
A1  - Zehe, E.
A1  - Ehret, U.
A1  - Pfister, L.
A1  - Blume, Theresa
A1  - Schroeder, Boris
A1  - Westhoff, M.
A1  - Jackisch, C.
A1  - Schymanski, Stanislauv J.
A1  - Weiler, M.
A1  - Schulz, K.
A1  - Allroggen, Niklas
A1  - Tronicke, Jens
A1  - van Schaik, Loes
A1  - Dietrich, Peter
A1  - Scherer, U.
A1  - Eccard, Jana
A1  - Wulfmeyer, Volker
A1  - Kleidon, Axel
T1  - HESS Opinions: From response units to functional units: a thermodynamic reinterpretation of the HRU concept to link spatial organization and functioning of intermediate scale catchments
JF  - Hydrology and earth system sciences : HESS
N2  - According to Dooge (1986) intermediate-scale catchments are systems of organized complexity, being too organized and yet too small to be characterized on a statistical/conceptual basis, but too large and too heterogeneous to be characterized in a deterministic manner. A key requirement for building structurally adequate models precisely for this intermediate scale is a better understanding of how different forms of spatial organization affect storage and release of water and energy. Here, we propose that a combination of the concept of hydrological response units (HRUs) and thermodynamics offers several helpful and partly novel perspectives for gaining this improved understanding. Our key idea is to define functional similarity based on similarity of the terrestrial controls of gradients and resistance terms controlling the land surface energy balance, rainfall runoff transformation, and groundwater storage and release. This might imply that functional similarity with respect to these specific forms of water release emerges at different scales, namely the small field scale, the hillslope, and the catchment scale. We thus propose three different types of "functional units" - specialized HRUs, so to speak - which behave similarly with respect to one specific form of water release and with a characteristic extent equal to one of those three scale levels. We furthermore discuss an experimental strategy based on exemplary learning and replicate experiments to identify and delineate these functional units, and as a promising strategy for characterizing the interplay and organization of water and energy fluxes across scales. We believe the thermodynamic perspective to be well suited to unmask equifinality as inherent in the equations governing water, momentum, and energy fluxes: this is because several combinations of gradients and resistance terms yield the same mass or energy flux and the terrestrial controls of gradients and resistance terms are largely independent. We propose that structurally adequate models at this scale should consequently disentangle driving gradients and resistance terms, because this optionally allow sequifinality to be partly reduced by including available observations, e. g., on driving gradients. Most importantly, the thermodynamic perspective yields an energy-centered perspective on rainfall-runoff transformation and evapotranspiration, including fundamental limits for energy fluxes associated with these processes. This might additionally reduce equifinality and opens up opportunities for testing thermodynamic optimality principles within independent predictions of rainfall-runoff or land surface energy exchange. This is pivotal to finding out whether or not spatial organization in catchments is in accordance with a fundamental organizing principle.
Y1  - 2014
U6  - https://doi.org/10.5194/hess-18-4635-2014
SN  - 1027-5606
SN  - 1607-7938
VL  - 18
IS  - 11
SP  - 4635
EP  - 4655
PB  - Copernicus
CY  - Göttingen
ER  -