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PhD Defense of Aurélien COSTES : “Two-way atmosphere-fire coupling for wildfire propagation : modeling, uncertainty and sensitivity “

  Tuesday 11 May 2021 at 14h30

  Phd Thesis       You Tube Link : https://youtu.be/tTiWqk1Vdxk    

Abstract :

A wildfire is the result of multi-scale interactions between vegetation, terrain topography and meteorological conditions, which may be enhanced by climate change. Understanding the processes that drive its behavior at the scale of an event is therefore a major issue for ecology and for public safety.

In this thesis work, the Blaze fire model was developed and integrated with the mesoscale atmospheric model Meso-NH in order to reconstruct the detailed chronology of a fire and thus provide a framework to study the interactions between the fire and the micro-meteorology. The response of the coupled Meso-NH/Blaze system to different modelling choices and atmospheric scenarios was studied to quantify the uncertainties associated with the quantities of interest (e.g. the position of the fire front and the latent and sensible heat fluxes along the fire front) and to identify the most influential parameters among those involved in the parameterizations of the propagation speed and heat fluxes. The results showed a significant influence of the atmospheric turbulence on the propagation speed and the fire-induced wind.

In its standard version, the Meso-NH atmospheric model is based on the anelastic hypothesis. The validity of this assumption is questionable in the vicinity of the flaming regions, which are subject to significant heat release. The compressible version of Meso-NH, previously developed for the dry atmosphere, has been extended to the humid atmosphere. A comparison between the anelastic and compressible systems was performed, using the coupled Meso-NH/Blaze model, on the FireFlux I prescribed burning experiment. The results showed that compressible effects become important at very high spatial resolution (10 m) and induce very fine-scale structures such as gravity waves in the fire-induced convection.

Jury :

François PIMONT – INRAE – Rapporteur

Albert SIMEONI – Worcester Polytechnic Institute University of Maryland – Rapporteur

Arnaud TROUVÉ – University of Maryland -Rapporteur

Jean-Baptiste FILIPPI – CNRS – Examinateur

Céline MARI – CNRS – Examinatrice

Christine LAC – Météo-France – Directrice

Mélanie ROCHOUX – CERFACS – Co-Directrice

Valéry MASSON – Météo-France – Co-Directeur (Invité)

CALENDAR

Friday

24

May

2024

🎓 PhD Defense: Théo DEFONTAINE

Friday 24 May 2024From 10h00 at 13h00

  Phd Thesis       JCA room, Cerfacs, Toulouse, France    

Monday

27

May

2024

🎓 PhD Defense: Thibault GIOUD

Monday 27 May 2024From 14h00 at 18h00

  Phd Thesis       Cerfacs, Toulouse, France    

Thursday

30

May

2024

Young PhD day (JDD2024@Cerfacs) – 30/05/2024

Thursday 30 May 2024From 9h00 at 17h00

  Journée des Doctorants       CERFACS     

ALL EVENTS