High resolution frontier simulations of extreme hydro-climatic events in Europe

Mean daily streamflow from 1950 to 2011 for Europe at 5 km spatial resolution. These simulations were obtained with the mHM (www.ufz.de/mhm) hydrological model using E-OBS forcing data. The ESM frontier simulations will be challenging because they will be done at 1 km spatial resolution.

Extreme hydrometeorological events such as floods and droughts lead to signifi- cant natural and socio-economic impacts. These events may bring societies and natural systems to their limits. Droughts, for example, may induce large famines, lead to increasing health risks to the population, may create drinking and irriga- tion water shortfalls inducing natural fires and degradation of soil and water qual- ity, and in many cases will cause large socio-economic losses. Europe, in particu- lar, has endured large scale drought-heat-wave events during the recent past (e.g., 2003 European drought), which have induced enormous socio-economic losses as well as casualties. Recent studies showed that the prediction of droughts and heatwaves is subject to large-scale forcing and parametric uncertainties that lead to considerable uncertainties in the projections of extreme characteristics such as drought magnitude/duration and area under drought, among others. These studies, however, show that extreme events such as that 2003 are to become twice as frequent, will lead to unprecedented changes in aridity and will affect a even large number of people than in the past (Samaniego et al. NCC, 2018). Conse- quently, we should aim to predict water fluxes and related states variables such as soil moisture “everywhere”and with low uncertainty so that the are “locally relevant” (Bierkens et al. HP 2014), or in other words, at high resolution and with low uncertainties. Tacking this grand challenge requires that the new gen- eration of global climate models should be able to operate at multiple spatial and temporal scales (seamless). Current reseach indicates that current land surface and hydrological models are suffering from serious shortcomings that impede to meet this challenge (Samaniego et al. HESS 2017).

For these reasons, for the ESM frontier simulations of extreme hydro-climatic events, we aim to develop stand-alone and parallelized versions of the multi- scale parameter regionalization and multiscale streamflow routing algorithms currently available for mHM only. There tools will be tested in the land surface model HTESSEL. Frontier simulations, including parameter estimation and ver- ification, based on the EDgE settings (http://edge.climate.copernicus.eu) at 1x1 km2 will also be performed in the JUWELS supercompurer

Luis Samaniego is a hydrological modeler with more that 20 years of experience. His main research interests are the further development of the mesoscale hydrologic model (www.ufz.de/mhm) and its multiscale parameter regionalization technique. His current research interest are on seasonal forecasting, climate change impacts, and drought and flood monitoring and forecasting at high resolution globally.