Développement et évaluation d'un modèle tridimensionnel de nuage chaud à microphysique détaillée

Aerosol particles hold a central position in the formation of cloud and precipitation because they are the condensation nuclei on which cloud drops form. The detailed description of the aerosol particles_ cloud interactions realized in an atmosphere with ils full three-dimensional complexity is essential. In this thesis, the warm cloud model with bin microphysics DESCAM is modified in order to allow its coupling with a three dimensional mesoscale non hydrostatic model of the Clark et al. (1996). DESCAM-3D is evaluated in two cloud situations. First, the impact of pollution on precipitation resulting from an increase of the aerosol particle concentration in the atmosphere is studied with idealized smulations performed over the Cévennes Mountains in France. Results show that an atmosphere plolluted and rich in condensation nuclei slow down considerably the convective dynamics and reduce rain formation and intensity at the surface. Then, the model has been evaluated for the measurements of the ACE-2 campaign. It shows a goodagreement with the observations and points out the impact of pollution on the microphysics and macrophysics (cloud cover, cloud water content) of the cloud fields in a three dimensional framework.Les particules d'aérosols tiennent une position centrale dans la formation des nuages. La description détaillée de l'interaction entre les particules d'aérosols et les nuages réalisée dans une dynamique tridimensionnelle est essentielle. Le modèle de nuage chaud à microphysique détaillée DESCAM est modifié pour permettre son couplage à la dynamique tridimensionnelle du modèle méso-échelle de Clark. DESCAM-3D est ensuite évalué dans le cadre de deux formations nuageuses. D'abord, l'impact sur les précipitations d'une pollution est étudié lors de simulations idéalisées réalisées sur le relief des Cévennes en France. Les résultats montrent qu'une atmosphère riche en noyaux de condensation ralentit considérablement la dynamique convective et réduit la formation de la pluie. Ensuite, le modèle couplé a été évalué à l'aide des mesures de l'expérience ACE-2. Il a montré un accord satisfaisant avec les observations et a aussi mis en évidence l'impact de la pollution sur le champ nuageux

Développement et évaluation d'un modèle tridimensionnel de nuage chaud à microphysique détaillée

CLERMONT FD-BCIU Sci.et Tech. (630142101) / SudocSudocFranceF

Reimagining Climate Futures: a Deliberative Dialogue on Circularity Part I

As the world gathered in Sharm el-Sheikh, Egypt forCOP27, seven years after the historic Paris Agreement,climate observers noted that the climate crisis isunraveling faster than ever before. With devasting floodsand wildfires, communities are seeking innovativesolutions that can be scaled quickly, provide resilience andensure sustainability for a diverse range of lifeforms. Withgreenhouse gas (GHG) emissions continuing to climb, andthe latest geopolitical threats making for an ever morecomplex environment, the pace of transformation of all oursystems needs to quicken, all the while ensuring a just andequitable transition for all.Fragmentation, siloeing, disconnection and politicalpolarization affect a wide range of human experiencesand systems and add to the complexity of climatesolutions. Research and science have also resulted in verycompartmentalized disciplines where trans- multi- andinter-disciplinary research, even if more and more active, isstill not very well evaluated and funded. As we increasinglyrealize we operate in complex and interconnected adaptivesystems, researching one subject becomes difficult withoutconsidering all connected topics, and their dynamics.There is a strong invitation and a need for a cultural shiftin how we view human systems and their relations to theenvironment. As scholars and practitioners, we proposed to convenean interdisciplinary, intersectoral and intercultural groupof academics, urbanists, public servants, elected officialsand citizens to develop a framework for climate-readinessbased on a circular model approach.The circularity framework for climate readiness willenable communities to reconnect with hope and developinnovative collaborative ideas and worldviews togetherwith concrete proofs-of-concept, such as in the circular citymodel currently tested in Europe, and scale efforts to meetthe challenges of our changing climate in a relational andcommunity-oriented way

Reimagining Climate Futures: a Deliberative Dialogue on Circularity Part I

As the world gathered in Sharm el-Sheikh, Egypt forCOP27, seven years after the historic Paris Agreement,climate observers noted that the climate crisis isunraveling faster than ever before. With devasting floodsand wildfires, communities are seeking innovativesolutions that can be scaled quickly, provide resilience andensure sustainability for a diverse range of lifeforms. Withgreenhouse gas (GHG) emissions continuing to climb, andthe latest geopolitical threats making for an ever morecomplex environment, the pace of transformation of all oursystems needs to quicken, all the while ensuring a just andequitable transition for all.Fragmentation, siloeing, disconnection and politicalpolarization affect a wide range of human experiencesand systems and add to the complexity of climatesolutions. Research and science have also resulted in verycompartmentalized disciplines where trans- multi- andinter-disciplinary research, even if more and more active, isstill not very well evaluated and funded. As we increasinglyrealize we operate in complex and interconnected adaptivesystems, researching one subject becomes difficult withoutconsidering all connected topics, and their dynamics.There is a strong invitation and a need for a cultural shiftin how we view human systems and their relations to theenvironment. As scholars and practitioners, we proposed to convenean interdisciplinary, intersectoral and intercultural groupof academics, urbanists, public servants, elected officialsand citizens to develop a framework for climate-readinessbased on a circular model approach.The circularity framework for climate readiness willenable communities to reconnect with hope and developinnovative collaborative ideas and worldviews togetherwith concrete proofs-of-concept, such as in the circular citymodel currently tested in Europe, and scale efforts to meetthe challenges of our changing climate in a relational andcommunity-oriented way