Assessing Cirrus Cloud Thinning Strategies by Learning from Aerosol-Cirrus Interactions in Natural and Perturbed Conditions

This project aims to evaluate the feasibility of cirrus cloud thinning (CCT) as a solar radiation management (SRM) strategy by improving our understanding of existing aerosol-cirrus interactions under both natural and perturbed conditions. Cirrus clouds significantly impact Earth’s radiation balance, yet their formation processes and interactions with aerosols remain poorly constrained and quantified, limiting our ability to model and manipulate them for climate intervention. To address this, the project integrates long-term satellite observations, Lagrangian air parcel tracking, and high-resolution modeling to (i) quantify aerosol-cirrus sensitivities in the natural atmosphere, (ii) analyze responses during high-pollution events (e.g., dust storms, wildfires), and (iii) enhance aerosol-cloud parameterizations in regional and global climate models. This multi-scale approach will deliver the first global, observation-based estimate for aerosol-cirrus interactions and their radiative effects, helping assess the physical plausibility, effectiveness, and risks of CCT strategies in mitigating climate change.

Odran Sourdeval obtained his Ph.D. in atmospheric physics from the University of Lille in 2012. Following a postdoctoral position at Leipzig University, he was appointed associate professor in atmospheric sciences at the University of Lille in 2018. His research advances the understanding of cloud processes, aerosol-cloud interactions, and their radiative effects by integrating remote sensing, modeling, and in situ observations. His current work focuses on refining observation-based estimates of the effective radiative forcing from aerosol-cloud interactions in both liquid and ice clouds, and on exploring the use of Lagrangian microphysical approaches to trace the origins of satellite-observed cloud properties. He was elected to the International Commission on Clouds and Precipitation in 2021.

Quentin Coopman has been an associate professor in atmospheric sciences at the University of Lille since 2023. He is currently working on developing new parametrization representing the impacts of aerosols on cloud droplet size and glaciation processes focusing on mixed-phase clouds. His work uses the synergy of satellite observations and numerical models to spatially and temporally collocate aerosol and cloud properties. Before that, he was a postdoctoral researcher in the remote sensing group at McGill University from February 2021 to August 2023 and at the Karlsruhe Institute of Technology from 2017 to 2021 in cloud physics, developing a cloud tracking algorithm from space-based observations to analyze the cloud thermodynamic phase transition. He did his Ph.D. in atmospheric science at the University of Utah and the University of Lille on the aerosol-cloud interaction in the Arctic.

Louis Marelle is a research fellow at the French national center for scientific research (CNRS) and LATMOS, Paris, France. He obtained his Ph.D. in 2016 in atmospheric chemistry and physics. He studies atmospheric composition at the poles and its impacts on polar climates, aerosol-cloud interactions, and the human drivers of extreme precipitation. By developing state-of-the art regional models of the atmosphere and analysis of model ensembles, he is leading the effort in modelling aerosol-cloud interactions in the EU-CRiceS project, and in modelling ice formation on aerosols and aerosol impacts on extreme weather in the EU-CERTAINTY project. He has contributed to the Arctic Monitoring and Assessment Programme (AMAP) reports for short-lived climate forcers the Arctic and is a member of the scientific steering committee of CATCH (the cryosphere and atmospheric chemistry).

Jean-Christophe Raut (Ph.D. in 2008) is an associate professor at Sorbonne University, Paris, and atmospheric physicist at LATMOS. He has experience developing and using mesoscale modelling (Polar WRF, WRF-Chem, FLEXPART-WRF, WRF-CHIMERE) to study key processes related to the transport, processing, ageing and deposition of aerosols in the Arctic region, their interactions with clouds and radiative impacts. He participated actively in a number of projects focusing on the Arctic region and has been an author of the Arctic Monitoring and Assessment Programme (AMAP) reports for short-lived climate forcers the Arctic. He is currently co-leading the ANR MPC2 project on Arctic mixed-phase clouds, is French representative at IASC (International Arctic Science Committee) within the Atmospheric Working Group, is member of scientific consortium of the TARA Polar Station as co-lead of the scoping group on long-term observations, and member of the steering committee of QuIESCENT (Quantifying the Indirect Effect: from Sources to Climate Effects of Natural and Transported aerosol in the Arctic), jointly developed between PACES and CATCH.