EGU2020-1563
https://doi.org/10.5194/egusphere-egu2020-1563
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Hydro-geomorphological response to changes in the spatial structure of extreme rainfall in a warmer world

Nadav Peleg1, Chris Skinner2, Simone Fatichi1,3, and Peter Molnar1
Nadav Peleg et al.
  • 1Institute of Environmental Engineering, ETH Zurich, Switzerland (nadav.peleg@sccer-soe.ethz.ch)
  • 2Energy and Environment Institute, University of Hull, UK
  • 3Department of Civil and Environmental Engineering, National University of Singapore, Singapore

Spatial characteristics of extreme rainfall are expected to change with increasing temperatures. Extreme rainfall directly affects streamflow and sediment transport volumes and peaks, yet the effect of climate change on the small-scale spatial structure of extreme rainfall and subsequent impacts on hydrology and geomorphology remain largely unexplored. Motivated by this knowledge gap, we conducted a numerical experiment in which synthetic rainfall fields representing extreme rainfall events of two types, stratiform and convective, were simulated using a space-time rainfall generator model (AWE-GEN-2d). The rainfall fields were modified to follow different spatial rainfall scenarios, associated with increasing temperatures, and used as inputs into a landscape evolution model (CAESAR-Lisflood). We found that the response of the streamflow and sediment yields are highly sensitive to changes in total rainfall volume and to a lesser extent to changes in localized peak rainfall intensities. The morphological (erosion and sediment transport) components were found to be more sensitive to changes in rainfall spatial structure in comparison to the hydrological components, and more sensitive to convective rainfall than stratiform rainfall because of localized runoff generation and erosion production. In addition, we showed that assuming extreme rainfall events to intensify with increasing temperatures without introducing a change in the rainfall spatial structure might lead to over-estimation of future climate impacts on basin-wide hydro-geomorphology.

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Presentation version 2 – uploaded on 05 May 2020 , no comments
Typo correction
Presentation version 1 – uploaded on 27 Apr 2020
  • CC1: Typo, Massimiliano Zappa, 05 May 2020

    Aug 2015 in point 3 is a typo, should be 2005 as in the remain of your contribution.

    You have the chance to update it. "See" you tomorrow

    Massimiliano

    • AC1: Reply to CC1, Peter Molnar, 05 May 2020

      Thanks Massimilano. Peter