Fire/atmosphere interactions

Editor's Notes

• #7: Qu’est-ce qui fait que de grands feux peuvent se développer ? Du feu de surface au feu de cimes Formation d’un panache s’étendant sur plusieurs dizaines voire centaines de km Difficile de stopper un très grand feu tel les megafires(favorisés par l’occurrence de plus en plus forte d’évènements extrêmes) Pour éviter que les feux atteignent des dimensions qui les rendent incontrôlables, il faut pouvoir prévoir rapidement où le feu va se propager et ainsi optimiser la stratégie de terrain. Des prévisions fiables de propagation à l’échelle régionale seraient nécessaires, en terme de comportement du feu et aussi de changement de comportement sous l’effet du changement climatique.
• #14: the generation of the stochastic ensemble must represent the anisotropy in wildfire spread. This anisotropy was implicitly introduced in the SE ap- proach by selecting spatially-distributed biomass fuel properties and distinct wind conditions between the different members in the ensemble. The SE approach was shown to be successful at retrieving at low computational cost (i.e., with a relatively small number of members in the ensemble) the actual shape of the fire front in cases with strong anisotropic propagation conditions. This approach was also found relevant for observations made with significant errors and/or cases in which the observations are incomplete (e.g., when only a section of the fireline is informed), in order to reconstruct a complete, reliable initial condition for FIREFLY restart.
• #19: ISBA est trop "grossier" les données en entrée font des km enrésolution, du coup pas possible et distribution spécifique. Le faireen HR c'est l'objet principal de l'ANR firecaster. Pour la caractérisation: données terrain (surface/volume... humiditéestimée (= f(humidité de l'air après 1 h pour le vegetal mort)) Pour la distribution spatiale : BDForêt / corine http://inventaire-forestier.ign.fr/spip/spip.php?rubrique53 Modèle 1D de couche limite, vent mi-maille << approx pourrie etinjustifiable mais meilleure que la fausse hauteur de flamme que l'onpeut diagnostiquer, c'était un des objectifs (trop audacieux) del'étude AVBP/Firestar d'avoir une vue du volume de gaz pour unemeilleure estimation.
• #20: Equivalent heat flux (W/m2) ➙ Energy over the hot gaseous column ➙ Multiplication of the nominal convection heat flux by the burning ratio Rb Water vapor mass flux (kg/m2/s) ➙ Multiplication of the nominal water loading by the burning ratio Rb Equivalent radiant temperature ➙ Nominal flame temperature Tn (1000 K) ➙ Soil temperature from the atmospheric model Ts (day temperature at ground level) ➙ Formulation of the radiant temperature Te (K): Te4 = (1 - Rb) Ts4 + Rb Tn4
• #21: - No anthropogenic emissions considered - No aerosol scheme - All species are emitted in the first surface level in the model and mixed in the boundary layer by the turbulence scheme. There is no a-priori injection height. A passive tracer (referred to as fire aerosol-like tracer) has been introduced to mimic fire-produced PM10 aerosols. The fire aerosol-like tracer is initialized to zero and has a deposition velocity of 3 cm/s (Seung-Muk et al. 2006); it is only emitted above the fire. - The simulated smoke plume was trapped within the boundary layer (injection height between 0.9 and 1.2km), a common feature of Mediterranean fires that mostly release emissions into the atmospheric boundary layer. - The coupled model with simplified assumptions concerning emissions and initialization simulated an sharp increase of O3 precursors near the fire and a subsequent O3 depletion in the fire plume (over 40km) as well as a strong increase of a fire aerosol-like tracer at the proper timing compared to the observations. Production of O3 (over the sea) was simulated several kilometers downwind of the fire as already observed in field campaigns.
• #22: ISBA est trop "grossier" les données en entrée font des km enrésolution, du coup pas possible et distribution spécifique. Le faireen HR c'est l'objet principal de l'ANR firecaster. Pour la caractérisation: données terrain (surface/volume... humiditéestimée (= f(humidité de l'air après 1 h pour le vegetal mort)) Pour la distribution spatiale : BDForêt / corine http://inventaire-forestier.ign.fr/spip/spip.php?rubrique53 Modèle 1D de couche limite, vent mi-maille << approx pourrie etinjustifiable mais meilleure que la fausse hauteur de flamme que l'onpeut diagnostiquer, c'était un des objectifs (trop audacieux) del'étude AVBP/Firestar d'avoir une vue du volume de gaz pour unemeilleure estimation.
• #23: - No anthropogenic emissions considered - No aerosol scheme - All species are emitted in the first surface level in the model and mixed in the boundary layer by the turbulence scheme. There is no a-priori injection height. A passive tracer (referred to as fire aerosol-like tracer) has been introduced to mimic fire-produced PM10 aerosols. The fire aerosol-like tracer is initialized to zero and has a deposition velocity of 3 cm/s (Seung-Muk et al. 2006); it is only emitted above the fire. - The simulated smoke plume was trapped within the boundary layer (injection height between 0.9 and 1.2km), a common feature of Mediterranean fires that mostly release emissions into the atmospheric boundary layer. - The coupled model with simplified assumptions concerning emissions and initialization simulated an sharp increase of O3 precursors near the fire and a subsequent O3 depletion in the fire plume (over 40km) as well as a strong increase of a fire aerosol-like tracer at the proper timing compared to the observations. Production of O3 (over the sea) was simulated several kilometers downwind of the fire as already observed in field campaigns.