My PhD project investigates the impact of climate change on the runoff regimes in Switzerland as well as on extreme moisture transports potentially leading to floods.


Hydro-CH2018 – new transient hydrological scenarios for Switzerland

Future changes in runoff regimes will affect many different sectors such as agriculture, energy production, or water management. Therefore, assessing future changes in runoff is very crucial for adaptation planners and decision-making authorities. Under the comprehensive framework Hydro-CH2018 (coordinated by the Swiss Federal Office for the Environment), we are simulating future runoff for the period 1981-2099 in Switzerland. The study uses the new transient Swiss climate change scenarios CH2018 (published by end of 2018; http://www.ch2018.ch/ ) with three different emission pathways (RCP2.6, RCP4.5 and RCP8.5) as input for the hydrological model. The hydrological simulations are run with the deterministic semi-distributed hydrological modelling system PREVAH and changes in glacier extents are simulated with a dynamic coupled ice flow-surface mass balance model. Over 180 regionalized meso-scale catchments distributed over Switzerland covering a wide range of different catchment characteristics are simulated and analyzed. The project determines potential runoff regime shifts and their seasonality under climate change. The transient property of the climate change scenarios allows for the first time to focus on the time of emergence of regime shifts and of changes in other hydrological indices. Further, analyzing trends in low flow (e.g. Q347) and high flow (e.g. flood frequency) indices provides a comprehensive perspective on the hydrological responses to climate change in Switzerland.


Future Changes in Moisture Transport towards the Alps

High amounts of integrated vapor transport (IVT) in the atmosphere directed perpendicular to orography often leads to heavy precipitation in the Alps and other mountainous areas around the world. Such high IVT reaching the Alps either from the south or the north were identified as important precursors for major floods in Switzerland. Thus, the future evolution of high IVT is of particular interest for adaptation planning. It is important to know how the moisture transport will evolve in future in terms of intensity but also flux direction. Therefore, we analyze IVT projections for the RCP8.5 scenario by models from the Coupled Model Intercomparison Project Phase 5 (CMIP5). First results show that the models project an intensification of IVT directed towards the Alps. The difference between future and historical periods is significant and becomes larger the more extreme the IVT and the further into the future. However, changes in IVT directed towards the Alps are smaller than the changes of all IVT events independent of direction. To analyze changes of extreme IVT we fitted Generalized Extreme Value (GEV) distributions to yearly block maxima. The resulting distributions and the corresponding parameters of the fits are then compared for future and historical periods. Fitting GEVs to yearly blockmaxima per pixel indicates that there is a shift in the distribution of extreme IVT from historical period to the far future period. Finally, we attempt to decompose the dynamical and the thermodynamical contribution to the detected changes in IVT and its extremes.

Jump to: 2018

2018

Brönnimann, Stefan; Rohr, Christian; Stucki, Peter; Summermatter, Stephanie; Bandhauer, Moritz; Barton, Yannick; Fischer, Andreas; Froidevaux, Paul Arnaud; Germann, Urs; Grosjean, Martin; Hupfer, Franziska; Ingold, Karin; Isotta, Francesco; Keiler, Margreth; Martius, Olivia; Messmer, Martina Barbara; Mülchi, Regula Isabelle; Panziera, Luca; Pfister, Lucas Martin; Raible, Christoph; ... (2018). 1868 - das Hochwasser, das die Schweiz veränderte. Ursachen, Folgen und Lehren für die Zukunft (Reihe G Grundlagenforschung G94). Bern: Geographica Bernensia 10.4480/GB2018.G94.01

Brönnimann, Stefan; Rohr, Christian; Stucki, Peter; Summermatter, Stephanie; Bandhauer, Moritz; Barton, Yannick; Fischer, Andreas; Froidevaux, Paul Arnaud; Germann, Urs; Grosjean, Martin; Hupfer, Franziska; Ingold, Karin; Isotta, Francesco; Keiler, Margreth; Martius, Olivia; Messmer, Martina Barbara; Mülchi, Regula Isabelle; Panziera, Luca; Pfister, Lucas Martin; Raible, Christoph; ... (2018). 1868 – L’alluvione che cambiò la Svizzera: Cause, conseguenze e insegnamenti per il futuro (Reihe G Grundlagenforschung G94). Bern: Geographica Bernensia 10.4480/GB2018.G94.02

Brönnimann, Stefan; Rohr, Christian; Stucki, Peter; Summermatter, Stephanie; Bandhauer, Moritz; Barton, Yannick; Fischer, Andreas; Froidevaux, Paul Arnaud; Germann, Urs; Grosjean, Martin; Hupfer, Franziska; Ingold, Karin; Isotta, Francesco; Keiler, Margreth; Martius, Olivia; Messmer, Martina Barbara; Mülchi, Regula Isabelle; Panziera, Luca; Pfister, Lucas Martin; Raible, Christoph; ... (2018). 1868 – Les inondations qui changèrent la Suisse : Causes, conséquences et leçons pour le futur (Reihe G Grundlagenforschung G94). Bern: Geographica Bernensia 10.4480/GB2018.G94.03

Brönnimann, Stefan; Rohr, Christian; Stucki, Peter; Summermatter, Stephanie; Bandhauer, Moritz; Barton, Yannick; Fischer, Andreas; Froidevaux, Paul Arnaud; Germann, Urs; Grosjean, Martin; Hupfer, Franziska; Ingold, Karin; Isotta, Francesco; Keiler, Margreth; Martius, Olivia; Messmer, Martina Barbara; Mülchi, Regula Isabelle; Panziera, Luca; Pfister, Lucas Martin; Raible, Christoph; ... (2018). 1868 - the flood that changed Switzerland: Causes, consequences and lessons for the future (Reihe G Grundlagenforschung G94). Bern: Geographica Bernensia 10.4480/GB2018.G94.04

2019

EGU General Assembly 2019, Vienna, Austria, 7-12/04/2019
Hydro-CH2018 – new transient hydrological scenarios for Switzerland, talk

20th Swiss Global Change Day, Bern, Switzerland, 7/02/2019
Future Changes in Moisture Transport Extremes, poster


2018

16th Swiss Geoscience Meeting, Bern, Switzerland, 30/11/-01/12/2018
Hydro-CH2018 – new transient hydrological scenarios for Switzerland, talk

17th Swiss Climate Summer School, Grindelwald, Switzerland, 26-31/08/2018
Future Changes in Moisture Transport Extremes, poster

8th GEWEX Open Scienec Conference: Extremes and Water on the Edge, Canmore, Canada, 06-11/05/2018
Future Changes in Moisture Transport towards the Alps, talk

EGU General Assembly 2018, Vienna, Austria, 09-13/04/2018
Future Changes in Moisture Transport towards the Alps, talk


2017

TWEX Annual Meeting ‘Translating weather extremes into the future’, Oslo, Norway, 28-29/11/2017
IVT & floods in Switzerland – overview of current research projects, talk (invited)

EGU General Assembly 2017, Vienna, Austria, 23-28/04/2017
Quantifying the present-day human influence on temperature, precipitation, and runoff in an pre-Alpine Swiss catchment, poster

18th Swiss Global Change Day, Bern, Switzerland, 11/04/2017
Human Influence on the Runoff Regime and Runoff Extremes of the River Thur?, poster (best poster award)

Oeschger Plenary Meeting, Bern, Switzerland, 13/02/2017
The influence of anthropogenic climate change on river runoff in Switzerland, talk (invited)

Workshop on Quantile Mapping, Bern, Switzerland, 20/01/2017
Lessons learned from bias correction of temperature and precipitation in Switzerland, talk (invited)