Novel extensions to the Fisher copula to model flood spatial dependence over North America

<p>Taking into account the spatial dependence of floods is essential for an accurate assessment of fluvial flood risk. We propose novel extensions to the Fisher copula to statistically model the spatial structure of observed historical flood record data across North America. These include the...

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Main Authors: D. A. Alexandre, C. Chaudhuri, J. Gill-Fortin
Format: Article
Language:English
Published: Copernicus Publications 2024-11-01
Series:Hydrology and Earth System Sciences
Online Access:https://hess.copernicus.org/articles/28/5069/2024/hess-28-5069-2024.pdf
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author D. A. Alexandre
C. Chaudhuri
J. Gill-Fortin
author_facet D. A. Alexandre
C. Chaudhuri
J. Gill-Fortin
author_sort D. A. Alexandre
collection DOAJ
description <p>Taking into account the spatial dependence of floods is essential for an accurate assessment of fluvial flood risk. We propose novel extensions to the Fisher copula to statistically model the spatial structure of observed historical flood record data across North America. These include the machine-learning-based XGBoost model, exploiting the information contained in 130 catchment-specific covariates to predict discharge Kendall's <span class="inline-formula"><i>τ</i></span> coefficients between pairs of gauged–ungauged catchments. A novel conditional simulation strategy is utilized to simulate coherent flooding at all catchments efficiently. After subdividing North America into 14 hydrological regions and 1.8 million catchments, applying our methodology allows us to obtain synthetic flood event sets with spatial dependence, magnitudes, and frequency resembling those of the historical events. The different components of the model are validated using several measures of dependence and extremal dependence to compare the observed and simulated events. The obtained event set is further analyzed and supports the conclusions from a reference paper in flood spatial modeling. We find a nontrivial relationship between the spatial extent of a flood event and its peak magnitude.</p>
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spelling doaj-art-9ee817082dbc409f960e31c61b39cf6c2025-08-20T02:48:33ZengCopernicus PublicationsHydrology and Earth System Sciences1027-56061607-79382024-11-01285069508510.5194/hess-28-5069-2024Novel extensions to the Fisher copula to model flood spatial dependence over North AmericaD. A. Alexandre0C. Chaudhuri1J. Gill-Fortin2Geosapiens Inc., Quebec City, QC, CanadaGeosapiens Inc., Quebec City, QC, CanadaGeosapiens Inc., Quebec City, QC, Canada<p>Taking into account the spatial dependence of floods is essential for an accurate assessment of fluvial flood risk. We propose novel extensions to the Fisher copula to statistically model the spatial structure of observed historical flood record data across North America. These include the machine-learning-based XGBoost model, exploiting the information contained in 130 catchment-specific covariates to predict discharge Kendall's <span class="inline-formula"><i>τ</i></span> coefficients between pairs of gauged–ungauged catchments. A novel conditional simulation strategy is utilized to simulate coherent flooding at all catchments efficiently. After subdividing North America into 14 hydrological regions and 1.8 million catchments, applying our methodology allows us to obtain synthetic flood event sets with spatial dependence, magnitudes, and frequency resembling those of the historical events. The different components of the model are validated using several measures of dependence and extremal dependence to compare the observed and simulated events. The obtained event set is further analyzed and supports the conclusions from a reference paper in flood spatial modeling. We find a nontrivial relationship between the spatial extent of a flood event and its peak magnitude.</p>https://hess.copernicus.org/articles/28/5069/2024/hess-28-5069-2024.pdf
spellingShingle D. A. Alexandre
C. Chaudhuri
J. Gill-Fortin
Novel extensions to the Fisher copula to model flood spatial dependence over North America
Hydrology and Earth System Sciences
title Novel extensions to the Fisher copula to model flood spatial dependence over North America
title_full Novel extensions to the Fisher copula to model flood spatial dependence over North America
title_fullStr Novel extensions to the Fisher copula to model flood spatial dependence over North America
title_full_unstemmed Novel extensions to the Fisher copula to model flood spatial dependence over North America
title_short Novel extensions to the Fisher copula to model flood spatial dependence over North America
title_sort novel extensions to the fisher copula to model flood spatial dependence over north america
url https://hess.copernicus.org/articles/28/5069/2024/hess-28-5069-2024.pdf
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AT jgillfortin novelextensionstothefishercopulatomodelfloodspatialdependenceovernorthamerica