Advancing global storm surge modelling using the new ERA5 climate reanalysis

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

This study examines the implications of recent advances in global climate modelling for simulating storm surges. Following the ERA-Interim (0.75° × 0.75°) global climate reanalysis, in 2018 the European Centre for Medium-range Weather Forecasts released its successor, the ERA5 (0.25° × 0.25°) reanalysis. Using the Global Tide and Surge Model, we analyse eight historical storm surge events driven by tropical—and extra-tropical cyclones. For these events we extract wind fields from the two reanalysis datasets and compare these against satellite-based wind field observations from the Advanced SCATterometer. The root mean squared errors in tropical cyclone wind speed reduce by 58% in ERA5, compared to ERA-Interim, indicating that the mean sea-level pressure and corresponding strong 10-m winds in tropical cyclones greatly improved from ERA-Interim to ERA5. For four of the eight historical events we validate the modelled storm surge heights with tide gauge observations. For Hurricane Irma, the modelled surge height increases from 0.88 m with ERA-Interim to 2.68 m with ERA5, compared to an observed surge height of 2.64 m. We also examine how future advances in climate modelling can potentially further improve global storm surge modelling by comparing the results for ERA-Interim and ERA5 against the operational Integrated Forecasting System (0.125° × 0.125°). We find that a further increase in model resolution results in a better representation of the wind fields and associated storm surges, especially for small size tropical cyclones. Overall, our results show that recent advances in global climate modelling have the potential to increase the accuracy of early-warning systems and coastal flood hazard assessments at the global scale.
Original languageEnglish
Pages (from-to)1007-1021
Number of pages15
JournalClimate Dynamics
Volume54
Issue number1-2
DOIs
Publication statusPublished - 6 Jan 2020

Funding

We would like to thank Martin Verlaan and Maialen Irazoqui Apecechea from Deltares for their support with the use of GTSM. We thank ECMWF for the use of the ECMWF ERA-Interim, ERA5 and IFS datasets. The authors also acknowledge Rein Haarsma and Ad Stoffelen from KNMI for sharing their expertise on ECMWF IFS and ASCAT. We thank SURFsara ( http://www.surfsara.nl ) for the support in using the Lisa Computer Cluster. The research leading to these results has received funding from the COASTRISK project financed by the SCOR Corporate Foundation for Science (R/003316.01). S.M. and J.D. have received funding from the C3S_422_Lot2_Deltares contract on coastal climate change (CoDEC), for the Copernicus Climate Change Service. J.A. and N.B. received funding from the Netherlands Organisation for Scientific Research (NWO) in the form of a VICI grant (Grant Number 453-13-006).

FundersFunder number
ASCAT
CoDEC
Copernicus Climate Change Service
KNMI
N.B.
SCOR Corporate Foundation for ScienceR/003316.01
VICI
Nederlandse Organisatie voor Wetenschappelijk Onderzoek453-13-006

    Keywords

    • Climate reanalysis
    • ECMWF Integrated Forecasting System
    • ERA5
    • Global hydrodynamic model
    • Storm surges

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