Researchers demonstrate that current models underestimate role of subsurface heterogeneity
A team of international researchers led by University of Freiburg hydrologist Dr. Andreas Hartmann suggests that inclusion of currently missing key hydrological processes in large-scale climate change impact models can significantly improve our estimates of water availability. The study shows that groundwater recharge estimates for 560 million people in karst regions in Europe, the Middle East and Northern Africa, are much higher than previously estimated from current large-scale models.
A karst region in Andalusia, Southern Spain. Photo: Matías Mudarra, Universität Malaga/Spanien
The scientists have shown that model estimates based on entire continents up to now have greatly underestimated in places the amount of groundwater that is recharged from fractions of surface runoff. This finding suggests that more work is needed to ensure sufficient realism in large-scale hydrologic models before they can be reliably used for local water management. The team has published their research findings in the scientific journal “Proceedings of the National Academy of Sciences (PNAS).“
Groundwater is a vital resource in many regions around the globe. For managing drinking water, the recharge rate is an important quantity for securing sustainable supplies. The researchers have compared two hydrological models that simulate groundwater recharge. One is a long-established global model with limited accounting for subsurface heterogeneity.
The other is a continental model the researchers have developed themselves that includes, for example, variability in the thickness of soils and different subsurface permeabilities. They have carried out the comparison for all of the karst regions in Europe, North Africa and the Middle East. Karst regions are known for their great degree of subsurface heterogeneity, because carbonate rock shows greater susceptibility to chemical weathering – a process that is known as karstification.
Karstification leads to varying soil depths and permeabilities. A comparison of the models' calculations with independent observations of groundwater recharge at 38 sites in the regions has shown that the model that accounts for heterogeneity produces more realistic estimates.
The researchers explain the reason for the difference between the two models as follows: In simulation, their newly developed model shows reduced fractions of surface According to the new model, a farmer in the Mediterranean region would potentially have up to a million liters more groundwater for extraction available in a year than the established model estimates, dependent on actual subsurface composition and the water demands of the local ecosystems.
When applied to the example of karst regions, the researchers' approach shows how it is possible to adapt global models used to predict water shortages, drought or floods to account more realistically for regional conditions. Scientists from the University of Freiburg, Canada's Victoria University, the University of Bristol in England and International Institute for Applied Systems Analysis in Austria took part in the study.
Hartmann, A., Gleeson, T., Wada, Y., Wagener, T., 2017. Enhanced groundwater recharge rates and altered recharge sensitivity to climate variability through subsurface heterogeneity. In: “Proceedings of the National Academy of Sciences”; doi:10.1073/pnas.1614941114.
Dr. Andreas Hartmann
Chair of Hydrology
University of Freiburg
Rudolf-Werner Dreier | Albert-Ludwigs-Universität Freiburg im Breisgau
Upcycling of PET Bottles: New Ideas for Resource Cycles in Germany
25.06.2018 | Fraunhofer-Institut für Betriebsfestigkeit und Systemzuverlässigkeit LBF
Dry landscapes can increase disease transmission
20.06.2018 | Forschungsverbund Berlin e.V.
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
19.07.2018 | Earth Sciences
19.07.2018 | Power and Electrical Engineering
19.07.2018 | Materials Sciences