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 :
- 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 :-/
Aerosol_cloud_meeting_LAERO.pdf
Aerosol_cloud_meeting_LAERO.pdf
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.
Un rapide tour de table nous a permis d’échanger plusieurs informations sur les nouvelles du laboratoire liées aux interactions nuages-aérosols :
- Arrivée de Inès Vongpaseut qui va travailler en thèse avec Christelle Barthe (dans le cadre du projet ICCARE) sur les interactions microphysique-électricité dans les nuages d’orage, en particulier sur les structures électriques anormales impliquant des aérosols désertiques
- 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