Minutes of the last meeting on Feb 7th 2023
The 4th meeting of the axe transverse nuages-aérosols took place on February 7, 2023 in the Jules Verne room at OMP.
It gathered 13 persons, with in presence : Sylvain Coquillat, Mathilde Leroux, Azusa Takeishi, Renaud Falga, Meredith Dournaux, Camille Mouchel-Vallon, Chien Wang, Marie Taufour and Vincent Noel. In remote (at the beginning…): Samira El Gdachi, Christelle Barthe, Pierre Tulet and Sybil de Sevin.
A quick roundtable allowed us to highlight :
- the arrival at the LAERO this month of Sybil de Sevin in her 3rd year at the Ecole de la Météo for her end of study project. She will work with Pierre on electrical anomalies in thunderstorms over Corsica
- the acceptance of a LEFE project submitted by Pierre Tulet on the removal of sea spray. The project includes a measurement campaign in 2024 on board the Marion Dufresne to measure the size distribution of aerosols in the Southern Ocean.
We then followed with a presentation by Azusa Takeishi.
Azusa first reminded us that the presence of aerosols impacts the size distribution of particles in clouds, and from there the precipitation rate and the cloud radiative impact. From there, she led a presentation in two parts:
- In the first part, Azusa discussed how taking into account aerosol emissions from biomass burning in mesoscale simulations (e.g., WRF) impacts the intensity of precipitation in Southeast Asia during El Nino events. El Nino events are characterized in that area by dry conditions that lead to an increase in fires. Azusa’s analysis first shows that including aerosol emissions from fires in simulations (using the FINN database) leads to an increase in precipitation. In other words, during dry years, aerosols from fires enhance surface rainfall through microphysical effects, which was consistently seen in the El Nino years of 2009 and 2015 (see Takeishi and Wang, 2022). Further, when the interactions between aerosols (biomass burning) and clouds are resolved explicitely (with WRF-CHEM), the increase in precipitation is ten times greater compared to a simple parameterization in WRF (see Takeishi and Wang 2023, under review). This is however at the cost of a 6 times higher computation time. It is difficult to determine which simulation is closer to reality (comparison with TRMM is difficult).
- After a session of discussion, in the second part of her talk Azusa presented an experiment that replaced in WRF several microphysical processes (of bulk type) by a Machine previously trained on a large number of bin-model simulations. A major challenge in this experiment was that the Machine Learning part was done in Python code (using the popular tools available for ML), but that the exploitation of the Machine had to be done in Fortran inside WRF.
The videoconferencing had some misfires beyond our control, which deprived the remote participants of the second part of the presentation. Sorry for that :-/
Previous meetings
Réunion 4 : 2023-02-07
The 4th meeting of the axe transverse nuages-aérosols took place on February 7, 2023 in the Jules Verne room at OMP.
It gathered 13 persons, with in presence : Sylvain Coquillat, Mathilde Leroux, Azusa Takeishi, Renaud Falga, Meredith Dournaux, Camille Mouchel-Vallon, Chien Wang, Marie Taufour and Vincent Noel. In remote (at the beginning…): Samira El Gdachi, Christelle Barthe, Pierre Tulet and Sybil de Sevin.
A quick roundtable allowed us to highlight :
It gathered 13 persons, with in presence : Sylvain Coquillat, Mathilde Leroux, Azusa Takeishi, Renaud Falga, Meredith Dournaux, Camille Mouchel-Vallon, Chien Wang, Marie Taufour and Vincent Noel. In remote (at the beginning…): Samira El Gdachi, Christelle Barthe, Pierre Tulet and Sybil de Sevin.
A quick roundtable allowed us to highlight :
- the arrival at the LAERO this month of Sybil de Sevin in her 3rd year at the Ecole de la Météo for her end of study project. She will work with Pierre on electrical anomalies in thunderstorms over Corsica
- the acceptance of a LEFE project submitted by Pierre Tulet on the removal of sea spray. The project includes a measurement campaign in 2024 on board the Marion Dufresne to measure the size distribution of aerosols in the Southern Ocean.
We then followed with a presentation by Azusa Takeishi. Azusa first reminded us that the presence of aerosols impacts the size distribution of particles in clouds, and from there the precipitation rate and the cloud radiative impact. From there, she led a presentation in two parts:
- In the first part, Azusa discussed how taking into account aerosol emissions from biomass burning in mesoscale simulations (e.g., WRF) impacts the intensity of precipitation in Southeast Asia during El Nino events. El Nino events are characterized in that area by dry conditions that lead to an increase in fires. Azusa’s analysis first shows that including aerosol emissions from fires in simulations (using the FINN database) leads to an increase in precipitation. In other words, during dry years, aerosols from fires enhance surface rainfall through microphysical effects, which was consistently seen in the El Nino years of 2009 and 2015 (see Takeishi and Wang, 2022). Further, when the interactions between aerosols (biomass burning) and clouds are resolved explicitely (with WRF-CHEM), the increase in precipitation is ten times greater compared to a simple parameterization in WRF (see Takeishi and Wang 2023, under review). This is however at the cost of a 6 times higher computation time. It is difficult to determine which simulation is closer to reality (comparison with TRMM is difficult).
- After a session of discussion, in the second part of her talk Azusa presented an experiment that replaced in WRF several microphysical processes (of bulk type) by a Machine previously trained on a large number of bin-model simulations. A major challenge in this experiment was that the Machine Learning part was done in Python code (using the popular tools available for ML), but that the exploitation of the Machine had to be done in Fortran inside WRF.
The videoconferencing had some misfires beyond our control, which deprived the remote participants of the second part of the presentation. Sorry for that :-/
Réunion 3 : 2022-11-25
La 3eme réunion de l’axe transverse nuages-aérosols du LAERO a eu lieu le 25 novembre 2022 en salle Boussinesq.
- Elle a regroupé :
- Christelle Barthe
- Sylvain Coquillat
- Meredith Dournaux
- Samira El Gdachi
- Dominique Lambert (visio)
- Mathilde Leroux (visio)
- Vincent Noel
- Pierre Tulet (visio)
- Inès Vongpaseut
Un rapide tour de table nous a permis d’échanger plusieurs informations sur les nouvelles du laboratoire liées aux interactions nuages-aérosols :
- Arrivée de Guillaume Feger qui va travailler en thèse avec Jean-Pierre Chaboureau et Thibaut Dauhut sur le rôle des poussières désertiques dans le développement de tempêtes tropicales
- Arrivée prochaine d’un stagiaire de M2 qui va travailler avec Pierre Tulet sur l’impact des poussières sur la structure des orages
Ensuite, Samira El Gdachi (doctorante du LACy) nous a présenté ses résultats sur l’étude des circulations thermiques et des nuages de pente sur l’île de la Réunion.
Il y eut de nombreuses questions très intéressantes. Les efforts héroïques de Sylvain ont rendu la visio possible.
Réunion 2 : 2022-03-18
La deuxième réunion de l’axe transverse nuages-aérosols du LAERO a eu lieu le vendredi 18 mars 2022. Après un rapide tour de table, nous avons enchainé avec la présentation de Mathilde Leroux : Que savons-nous aujourd’hui sur les nuages stratosphériques polaires ?
Des problèmes techniques ont malheureusement rendu la visio impraticable.
Avant de clore la réunion, on rappelle qu’il est prévu que le LAERO finance des stages de M2 dans le cadre de l’axe transverse. Il reste environ 6 mois pour proposer un sujet.
Réunion 1 : 2021-11-25
La première réunion de l’axe transverse nuages-aérosols a eu lieu au Laboratoire d’Aérologie le 25 novembre 2021 de 10h à midi. Elle a regroupé :
- Jean-Pierre Chaboureau
- Sylvain Coquillat
- Lambert Delbeke
- Mathilde Leroux
- Camille Mouchel-Vallon
- Vincent Noel
- Véronique Pont
Après un rapide tour de table pour expliquer comment les travaux de chaque participant-e touchent à la problématique nuages-aérosols, nous avons enchainé avec deux présentations.
Présentation 1 : Influence of Different Atmospheric Aerosol Compositions on the Life Cycle of Stratiform Clouds over Southern West Africa (Lambert Delbeke).
Présentation 2 : SAETTA : l’imagerie haute résolution des éclairs témoin des interactions orages-aérosols (Sylvain Coquillat)
A l’issue des présentations et des discussions qui suivirent, nous avons envisagé plusieurs possibles additions pour les prochaines réunions :
- point d’actualités labo concernant l’axe nuages-aérosols (conférences, nouveaux arrivants doctorants et post-doctorants, projets en cours ou à venir, etc)
- une réunion axée sur les méthodes d’observations pouvant contribuer à l’étude des interactions nuages-aérosols
- ne réunion axée sur les modélisations pouvant contribuer à l’étude des interactions nuages-aérosols
- la mise en place d’une visio pour élargir le périmètre des participants (notamment vers Lannemezan)
La prochaine réunion est prévue pour mi-février.