Description of the thesis topic

Can atmospheric observations provide indicators of the effectiveness of urban CO₂ emission reduction measures?

Work Context

This doctoral project is part of the PEPR RESILIENCE initiative and the ITEM OASIS project, which aims to support resilient urban development in the face of climate change, air pollution, and urban heat islands. It focuses on CO₂ emission reduction in Marseille and, to a lesser extent, Lille. Cities account for over 70% of fossil CO₂ emissions, but urban inventories often contain significant uncertainties. Atmospheric measurements (in situ and remote sensing) provide a robust method to assess and improve emission inventories and to monitor the effectiveness of reduction measures.
The project will develop an atmospheric monitoring method to track CO₂ concentration changes relative to implemented reduction measures, using long-term observatory datasets since 2016. The candidate will investigate how anthropogenic emissions, biogenic fluxes, and atmospheric conditions affect CO₂ levels, using COVID-19 lockdowns as test cases. Field campaigns will take place in Marseille and Lille to study the impact of urban planning interventions on CO₂ concentrations. Carbon isotope analyses will be performed in collaboration with the ICOS European Research Infrastructure to identify emission sources. Robust classification of CO₂ data in function of environmental conditions will enable reliable year-to-year comparisons and possibly the development of indicator(s) to assess the effectiveness of emission reduction policies.
The work will also evaluate emerging satellite datasets for monitoring CO₂ and co-emitted species, and integrate inventory and geomatic data to develop indicators of emission reduction effectiveness.
Missions
 Compare atmospheric CO₂ and co-emitted species with inventories to improve them.
 Develop clustering methods to compare data under similar atmospheric conditions.
 Analyze spatial and satellite data to assess urban planning and CO₂ emission trends.
 Evaluate COVID-related variations in emissions.
 Support field data collection and quality monitoring at Marseille-Longchamp.
 Develop, or assess the feasibility of developing, indicators to track CO₂ emission trends.
Activities
 Process, calibrate, and validate datasets, including Lidar aerosol data, in collaboration with the Atmospheric Optics Laboratory of Lille.
 Coordinate isotopic analyses with ICOS Europe.
 Classify CO₂ data according to atmospheric conditions (wind, temperature, mixing height, etc.).
 Operate instruments and participate in field campaigns.
 Monitor data quality and support instrument maintenance.
 Perform back-trajectory and footprint analyses using HYSPLIT.
 Collect and analyze spatial CO₂ and emission tracer data; potential NASA/JPL collaboration.
 Study 10-year CO2 emission trends using different inventories.
 Collaborate with PEPR RESILIENCE to assess emission reduction implementation and barriers.
 Synthesize sectoral emission reduction measures.
 Analyze carbon sink evolution using in situ, spatial data, and literature, in collaboration with ICOS and CNRS ecosystem monitoring networks.
Required profile
 Master's degree in Atmospheric Sciences or a related field.
 Proficiency in programming (R) and statistical analysis.
 Knowledge of remote sensing required.
 Fluent in French.
 English proficiency, minimum B1 level.
 Meticulous, proactive, responsive, and able to work in a team.
 Ability to conduct fieldwork and handle scientific instruments.
 Driver's license (B) desirable.

Working Environment
The PhD candidate will join the Atmosphere group of the PAHIS team at IMBE. Support will be provided by a research engineer for database and instrument maintenance. Weekly supervision meetings will be held, and the candidate will be integrated into the PEPR RESILIENCE multidisciplinary consortium of physicists, chemists, geographers, urban planners, sociologists, and emission inventory specialists.

Constraints and risks

• Intensive field campaigns in Marseille (September) and Lille (June)
• Occasional long or demanding fieldwork days
• Rapid problem-solving and adaptability required for instrument operation