Journal cover Journal topic
Natural Hazards and Earth System Sciences An interactive open-access journal of the European Geosciences Union
Journal topic

Journal metrics

Journal metrics

  • IF value: 2.883 IF 2.883
  • IF 5-year value: 3.321 IF 5-year
    3.321
  • CiteScore value: 3.07 CiteScore
    3.07
  • SNIP value: 1.336 SNIP 1.336
  • IPP value: 2.80 IPP 2.80
  • SJR value: 1.024 SJR 1.024
  • Scimago H <br class='hide-on-tablet hide-on-mobile'>index value: 81 Scimago H
    index 81
  • h5-index value: 43 h5-index 43
Discussion papers
https://doi.org/10.5194/nhess-2019-174
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/nhess-2019-174
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

Submitted as: research article 06 Jun 2019

Submitted as: research article | 06 Jun 2019

Review status
This discussion paper is a preprint. It is a manuscript under review for the journal Natural Hazards and Earth System Sciences (NHESS).

Simulations of the 2005, 1910 and 1876 Vb cyclones over the Alps – Sensitivity to model physics and cyclonic moisture flux

Peter Stucki1,2, Paul Froidevaux2,4, Marcelo Zamuriano1,2, Francesco Alessandro Isotta4, Martina Messmer1,3,a, and Andrey Martynov1,2 Peter Stucki et al.
  • 1Oeschger Centre for Climate Change Research, University of Bern, Bern, 3012, Switzerland
  • 2Institute of Geography, University of Bern, Bern, 3012, Switzerland
  • 3Climate and Environmental Physics, Physics Institute, University of Bern, Bern, 3012, Switzerland
  • 4Federal Office for Meteorology and Climatology MeteoSwiss, Zurich-Airport, 8058, Switzerland
  • anow at: School of Earth Sciences, The University of Melbourne, Melbourne, Victoria, Australia

Abstract. In June 1876, June 1910 and August 2005, northern Switzerland was severely impacted by heavy precipitation and extreme floods. Although occurring in three different centuries, all three events featured very similar precipitation patterns and an extra-tropical storm following a cyclonic, so called Vb trajectory around the Alps. Going back in time from the recent to the historical cases, we explore the potential of dynamical downscaling a global reanalysis product from a grid size of 220 km to 3 km. We use the full, 56-member ensemble provided in the reanalysis and a regional weather model to investigate sensitivities of the simulated precipitation amounts to a set of differing model configurations. These setups are evaluated by combining spatial verification metrics, inter-subjective visual inspection and an objective similarity measure. The best-performing model setup, featuring a 1-day initialization period and moderate spectral nudging, is then applied to assess the sensitivity of simulated precipitation totals to cyclonic moisture flux along the downscaling steps. The analyses show that cyclone fields and tracks are well defined in the reanalysis ensemble for the 2005 and 1910 cases, while deviations increase for the 1876 case. In the downscaled ensemble, the accuracy of simulated precipitation totals is closely linked to the exact trajectory of the cyclone, with slight shifts producing erroneous precipitation, e.g., due to a break-up of the vortex if simulated too close to the Alpine topography. To reproduce the extreme events, continuous moisture fluxes of > 200 kg m−1s−1 from accurate directions are required. Misplacements of the vortex, in particular for the 1876 case, point to limitations of downscaling from coarse input for such complex weather situations and for the more distant past. On the upside, a well-reasoned selection of reanalysis members for downscaling may be adequate in cases where the driving large-scale features in the atmosphere are well known.

Peter Stucki et al.
Interactive discussion
Status: final response (author comments only)
Status: final response (author comments only)
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
[Login for Authors/Editors] [Subscribe to comment alert] Printer-friendly Version - Printer-friendly version Supplement - Supplement
  • RC1: 'Review', Anonymous Referee #1, 27 Jun 2019 Printer-friendly Version
  • RC2: 'review', Anonymous Referee #2, 24 Jul 2019 Printer-friendly Version Printer-friendly Version
  • RC3: 'Review', Anonymous Referee #3, 11 Aug 2019 Printer-friendly Version Printer-friendly Version
Peter Stucki et al.
Peter Stucki et al.
Viewed  
Total article views: 269 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
219 49 1 269 0 0
  • HTML: 219
  • PDF: 49
  • XML: 1
  • Total: 269
  • BibTeX: 0
  • EndNote: 0
Views and downloads (calculated since 06 Jun 2019)
Cumulative views and downloads (calculated since 06 Jun 2019)
Viewed (geographical distribution)  
Total article views: 195 (including HTML, PDF, and XML) Thereof 193 with geography defined and 2 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Cited  
Saved  
No saved metrics found.
Discussed  
No discussed metrics found.
Latest update: 22 Aug 2019
Publications Copernicus
Download
Short summary
In 1876, 1910 and 2005, Switzerland was impacted by extreme rainfall and floods. All events were linked to a Vb cyclone. We test a range of weather model setups (short spin-up and standard physics are best) to understand the sensitivity of atmospheric dynamics. The simulated Vb cyclones are (not) well defined for 2005 and 1910 (1876). To reproduce the events, intense moisture flux from the right direction is needed. Storms that slightly deviate from an ideal path produce erroneous precipitation.
In 1876, 1910 and 2005, Switzerland was impacted by extreme rainfall and floods. All events were...
Citation