Research ArticleCLIMATOLOGY

Higher probability of compound flooding from precipitation and storm surge in Europe under anthropogenic climate change

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Science Advances  18 Sep 2019:
Vol. 5, no. 9, eaaw5531
DOI: 10.1126/sciadv.aaw5531
  • Fig. 1 Synoptic weather conditions driving extreme events.

    Composite maps of sea level pressure (hPa, in white) and total column water fields computed over days where extreme events (>99.5th percentile) occurred in Plymouth (UK, top) and Ancona (Italy, bottom) indicated by the red dots (based on ERA-Interim data, 1980–2014). Here, the astronomical tide component of the sea level is not considered to focus only on the meteorological-driven part. Extreme events type: (A and D) compound flooding (CF), (B and E) storm surge but not extreme precipitation, and (C and F) extreme precipitation but not storm surge. The total number of extreme events considered for computing the composite maps is shown at the bottom left corner of the panels. Storm surges include the wave setup contribution (see text).

  • Fig. 2 Present probability of potential compound flooding (CF).

    Return periods of CF (co-occurring sea level and precipitation extremes, i.e., larger than the individual 1-year return levels) based on ERA-Interim data.

  • Fig. 3 Future probability of potential compound flooding (CF).

    (A) Multimodel mean of projected change (%) of CF return periods, between future (2070–2099) and present (1970–2004) climate. (B) Return periods for the future (2070–2099). Gray points indicate locations where only four or fewer of six models agree on the sign of the return period change (three or less of five models in the Black Sea). Areas of gray points in (A) and (B) are slightly different, as the former are computed taking into account the past period (1970–2004) and the latter the period (1980–2004) (see delta change approach in Materials and Methods). (C) Median value of CF return periods over regions defined in (B) for past [1980–2014, based on ERA-Interim (Fig. 2)] and future (2070–2099) climate, separately for individual models. For ERA-Interim, gray shading illustrates the sampling uncertainty 95% range.

  • Fig. 4 Attribution of probability change in potential compound flooding (CF) to changes in dependence and marginal distribution.

    Multimodel mean of projected change (%) of CF return periods between future (2070–2099) and present (1970–2004) when only taking into account future changes of: the overall (A) dependence [Spearman and tail dependence (3)] between sea level and precipitation, (B) sea level distribution, and (C) precipitation distribution (Materials and Methods). The total projected probability variation (Fig. 3A) is not given by the sum of these three cases (A, B, and C), as the overall dependencies and marginal distributions do not contribute linearly to the CF return periods. SLR is not considered in the definition of future sea levels (see text). Gray points indicate locations where only four or fewer of six models agree on the sign of the return period change (three or less of five models in the Black Sea).

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/5/9/eaaw5531/DC1

    Relative SLR influence on extreme sea level and CF

    Bivariate validation

    Univariate return periods

    Fig. S1. Relative SLR influence on extreme sea level and CF.

    Fig. S2. Extreme values of sea level and precipitation.

    Fig. S3. Comparison of the dependence between sea level and precipitation based on ERA-Interim and observation data.

    Fig. S4. Comparison of the return periods of potential CF based on ERA-Interim and observation data.

    Fig. S5. Probability of potential compound flood based on individual models.

    Fig. S6. Changes in probability of potential compound flood driven by the astronomical tides.

    Fig. S7. Changing return periods of extreme sea level (no SLR) and precipitation.

    Fig. S8. Regional effects of SLR-driven changes of astronomical tide amplitudes on changing probability of potential compound flood.

    Fig. S9. Procedure for computing compound flood return periods.

    Fig. S10. Future change of CF return periods based on individual models.

    References (4144)

  • Supplementary Materials

    This PDF file includes:

    • Relative SLR influence on extreme sea level and CF
    • Bivariate validation
    • Univariate return periods
    • Fig. S1. Relative SLR influence on extreme sea level and CF.
    • Fig. S2. Extreme values of sea level and precipitation.
    • Fig. S3. Comparison of the dependence between sea level and precipitation based on ERA-Interim and observation data.
    • Fig. S4. Comparison of the return periods of potential CF based on ERA-Interim and observation data.
    • Fig. S5. Probability of potential compound flood based on individual models.
    • Fig. S6. Changes in probability of potential compound flood driven by the astronomical tides.
    • Fig. S7. Changing return periods of extreme sea level (no SLR) and precipitation.
    • Fig. S8. Regional effects of SLR-driven changes of astronomical tide amplitudes on changing probability of potential compound flood.
    • Fig. S9. Procedure for computing compound flood return periods.
    • Fig. S10. Future change of CF return periods based on individual models.
    • References (4144)

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