Challenges in assessing Fire Weather changes in a warming climate

Abstract The Canadian Fire Weather Index (FWI), widely used to assess wildfire danger, typically relies on noon-specific meteorological data. However, climate models often provide only daily aggregated values, posing a challenge for accurate FWI calculations. We evaluated daily approximations for FW...

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Main Authors: Aurora Matteo, Ginés Garnés-Morales, Alberto Moreno, Andreia F. S. Ribeiro, Cesar Azorin-Molina, Joaquín Bedia, Francesca Di Giuseppe, Robert J. H. Dunn, Sixto Herrera, Antonello Provenzale, Yann Quilcaille, Miguel Ángel Torres-Vázquez, Marco Turco
Format: Article
Language:English
Published: Nature Portfolio 2025-07-01
Series:npj Climate and Atmospheric Science
Online Access:https://doi.org/10.1038/s41612-025-01163-0
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author Aurora Matteo
Ginés Garnés-Morales
Alberto Moreno
Andreia F. S. Ribeiro
Cesar Azorin-Molina
Joaquín Bedia
Francesca Di Giuseppe
Robert J. H. Dunn
Sixto Herrera
Antonello Provenzale
Yann Quilcaille
Miguel Ángel Torres-Vázquez
Marco Turco
author_facet Aurora Matteo
Ginés Garnés-Morales
Alberto Moreno
Andreia F. S. Ribeiro
Cesar Azorin-Molina
Joaquín Bedia
Francesca Di Giuseppe
Robert J. H. Dunn
Sixto Herrera
Antonello Provenzale
Yann Quilcaille
Miguel Ángel Torres-Vázquez
Marco Turco
author_sort Aurora Matteo
collection DOAJ
description Abstract The Canadian Fire Weather Index (FWI), widely used to assess wildfire danger, typically relies on noon-specific meteorological data. However, climate models often provide only daily aggregated values, posing a challenge for accurate FWI calculations. We evaluated daily approximations for FWI95d—the annual count of extreme fire-weather days—against the standard noon-based method (1980–2023). Our findings reveal that noon-based FWI95d show a global increase of ~65% (11.66 days over 44 years). In contrast, daily approximations tend to overestimate these trends by 5–10%, with combinations involving minimum relative humidity showing the largest divergences. Globally, up to 15 million km²—particularly in the western United States, southern Africa, and parts of Asia—exhibit significant overestimations. We recommend (i) prioritizing the inclusion of sub-daily meteorological data in future climate model intercomparison projects to enhance FWI accuracy, and (ii) adopting daily mean approximations as the least-biased alternative if noon-specific data are unavailable.
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institution Kabale University
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publishDate 2025-07-01
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series npj Climate and Atmospheric Science
spelling doaj-art-0b6ec870f4bb4f0a88bc2a5fe48d3bce2025-08-20T04:01:53ZengNature Portfolionpj Climate and Atmospheric Science2397-37222025-07-01811810.1038/s41612-025-01163-0Challenges in assessing Fire Weather changes in a warming climateAurora Matteo0Ginés Garnés-Morales1Alberto Moreno2Andreia F. S. Ribeiro3Cesar Azorin-Molina4Joaquín Bedia5Francesca Di Giuseppe6Robert J. H. Dunn7Sixto Herrera8Antonello Provenzale9Yann Quilcaille10Miguel Ángel Torres-Vázquez11Marco Turco12Department of Earth Sciences, University of PisaDepartment of Physics, Regional Campus of International Excellence (CEIR) Campus Mare Nostrum, University of MurciaDepartment of Physics, Regional Campus of International Excellence (CEIR) Campus Mare Nostrum, University of MurciaDepartment of Compound Environmental Risks, Helmholtz Centre for Environmental Research - UFZCentro de Investigaciones sobre Desertificación, Consejo Superior de Investigaciones Científicas (CIDE, CSIC-UV-Generalitat Valenciana), Climate, Atmosphere and Ocean Laboratory (Climatoc-Lab), MoncadaDepartamento de Matemática Aplicada y Ciencias de la Computación (MACC), Universidad de CantabriaEuropean Center for Medium-range Weather Forecast (ECMWF), Reading, UK 7Met Office Hadley CentreMet Office Hadley CentreDepartamento de Matemática Aplicada y Ciencias de la Computación (MACC), Universidad de CantabriaInstitute of Geosciences and Earth Resources, CNRInstitute for Atmospheric and Climate Science, Department of Environmental Systems Science, ETH ZurichDepartment of Physics, Regional Campus of International Excellence (CEIR) Campus Mare Nostrum, University of MurciaDepartment of Physics, Regional Campus of International Excellence (CEIR) Campus Mare Nostrum, University of MurciaAbstract The Canadian Fire Weather Index (FWI), widely used to assess wildfire danger, typically relies on noon-specific meteorological data. However, climate models often provide only daily aggregated values, posing a challenge for accurate FWI calculations. We evaluated daily approximations for FWI95d—the annual count of extreme fire-weather days—against the standard noon-based method (1980–2023). Our findings reveal that noon-based FWI95d show a global increase of ~65% (11.66 days over 44 years). In contrast, daily approximations tend to overestimate these trends by 5–10%, with combinations involving minimum relative humidity showing the largest divergences. Globally, up to 15 million km²—particularly in the western United States, southern Africa, and parts of Asia—exhibit significant overestimations. We recommend (i) prioritizing the inclusion of sub-daily meteorological data in future climate model intercomparison projects to enhance FWI accuracy, and (ii) adopting daily mean approximations as the least-biased alternative if noon-specific data are unavailable.https://doi.org/10.1038/s41612-025-01163-0
spellingShingle Aurora Matteo
Ginés Garnés-Morales
Alberto Moreno
Andreia F. S. Ribeiro
Cesar Azorin-Molina
Joaquín Bedia
Francesca Di Giuseppe
Robert J. H. Dunn
Sixto Herrera
Antonello Provenzale
Yann Quilcaille
Miguel Ángel Torres-Vázquez
Marco Turco
Challenges in assessing Fire Weather changes in a warming climate
npj Climate and Atmospheric Science
title Challenges in assessing Fire Weather changes in a warming climate
title_full Challenges in assessing Fire Weather changes in a warming climate
title_fullStr Challenges in assessing Fire Weather changes in a warming climate
title_full_unstemmed Challenges in assessing Fire Weather changes in a warming climate
title_short Challenges in assessing Fire Weather changes in a warming climate
title_sort challenges in assessing fire weather changes in a warming climate
url https://doi.org/10.1038/s41612-025-01163-0
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