Modelling urban micrometeorology

  • Villenave-d'Ornon, Gironde
  • CDD
  • Temps-plein
  • Il y a 16 jours
Offer DescriptionWith global warming and the increase in the world's urban population, thermal comfort and health risks in cities are becoming critical during heat waves. The introduction of trees in cities is often advocated as a way of regulating the urban heat island and improving thermal comfort and air quality, in a context of global warming. However, in certain configurations, trees can limit the ventilation of neighbourhood streets, preventing the dispersion of pollutants emitted into the streets and altering thermal comfort. These uncertainties about the benefits of urban trees on the microclimate and the dispersion of pollutants need to be clarified in order to propose relevant urban greening strategies.To assess the impact of trees in cities, we need a better understanding of their influence on turbulent exchanges of mass (water vapour, CO2, particles) and energy between the urban canopy and the atmosphere, from the scale of the street to that of the entire city, for different meteorological conditions. To achieve this, multi-scale modelling of canopy-atmosphere exchanges is required in a meteorological model, with an evolving representation of the vegetated urban canopy and multi-process interactions (radiation, heat and moisture transfers, turbulence, etc.) between trees and the built environment, depending on the resolution of the simulation.The goal of this PhD is to study the impact of urban trees on micrometeorology and particle dispersion at scales ranging from the neighbourhood to the city. To do this, this PhD will develop innovative modelling based on the coupling between (1) a meteorological model adapted to fine spatial scales and explicitly simulating turbulent structures, and (2) a multi-layer model of a vegetated urban canopy adapted to the scale of urban neighbourhoods, estimating mass and energy flows in the urban canopy. Combined with an experimental campaign in the city of Nantes, this innovative modelling will make it possible (1) to understand the role played by trees in the variability of micrometeorological fields and the ventilation process in the canopy at the scales studied, and (2) to investigate urban vegetation scenarios with a view to mitigating climatic extremes.The originality of this PhD lies in (1) taking an interest in the little-studied scale of the neighbourhood, an intermediate scale between the city and the street, for different thermal stabilities ranging from windy to warm days, (2) combining modelling and in situ measurements, and (3) to simulate the unsteady nature (explicit representation of turbulent motions) of micrometeorological and dispersion fields in order to understand the exchange mechanisms and interactions between spatial scales generated by the heterogeneities of the urban canopy and those linked to the atmospheric boundary layer.This PhD is part of the more general ANR CITRY project (Contribution of urban trees to microclimate and pollutant dispersion from local to city scales) (2024-2028). The aim of this project is to assess the multi-scale influence of urban trees, from the street to the entire city, on the urban microclimate and the dispersion of pollutants, taking into account variations in atmospheric thermal stability. In this project, this PhD deals with scales ranging from the neighbourhood to the city, while another PhD at the at the Ecole Centrale de Nantes will look at scales ranging from the local to the neighbourhood, with an explicit representation of buildings to study turbulent exchanges between the canopy and the atmosphere. A strong interaction between these two PhDs is expected, in order to ultimately cover the continuum of scales from the street to the city.Funding category: Autre financement public
French National Research Agency, funding already acquired
PHD title: Environmental Physics
PHD Country: FranceRequirementsSpecific RequirementsMaster or engineer in fluid mechanics, atmospheric physics, or geophysics with an interest in modelling
Good experience in programming under Linux environment
Excellent writing skills, fluent in English
Rigorous, autonomous, creative and motivated by working in a research environmentAdditional InformationWork Location(s)Number of offers available 1 Company/Institute Institut national de recherche pour l'agriculture, l'alimentation et l'environnement Country France City Villenave d'OrnonWhere to apply WebsiteSTATUS: EXPIRED

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