Organisation/Company: CNRS
Department: Laboratoire inter-universitaire des systèmes atmosphèriques
Research Field: Environmental science
Researcher Profile: Recognised Researcher (R2)
Country: France
Application Deadline: 5 Dec 2024 - 00:00 (UTC)
Type of Contract: Temporary
Job Status: Full-time
Hours Per Week: 35
Offer Starting Date: 1 Jan 2025
Is the job funded through the EU Research Framework Programme? Not funded by a EU programme
Is the Job related to staff position within a Research Infrastructure? No
Offer Description
Organic compounds in the atmosphere have an impact on air quality and climate. However, quantifying these impacts remains a delicate task, given the uncertainties associated with the speciation and emission fluxes of primary organic compounds, as well as to the reactivity and mass transfer of secondary organic compounds. These uncertainties are particularly acute during the summer months, when climate change brings extreme weather conditions and high levels of photochemical pollution.
The aim of this post-doctoral project is to improve the representation of organic carbon evolution in air quality models in summer under a context of climate change.
During the summer of 2022, characterized by several heatwave periods that can be used as an analogue for a future climate, highly detailed observations of atmospheric chemical composition were carried out simultaneously in different types of environments in France: background sites as part of the EMEP campaign, as well as urban (Paris), suburban (SIRTA), and forest (Rambouillet forest) sites as part of the ACROSS campaign. These detailed observations are strong constraints for evaluating and improving our understanding of the processes incorporated in the models.
However, a direct comparison between air quality model simulations and detailed measurements is tricky. Indeed, in these models, the thousands of organic compounds present in the atmosphere are aggregated into a hundred or so model species, right from the emission stage, resulting in a significant loss of information on the speciation of individual organic compounds, and on their physico-chemical properties. Evaluating and improving the representation of processes in air quality models thus requires an essential intermediate step of comparing detailed observations with explicit modeling.
As part of this post-doc, highly detailed chemical simulations and 3D simulations with the CHIMERE air quality model will be carried out jointly. Explicit simulations of organic carbon evolution will be carried out in a box model configured to represent the different measurement sites of summer 2022. This model will use the same input data in terms of emissions and meteorology as the CHIMERE model. Comparisons between the explicit model and measurements will allow to assess the emission fluxes and speciation of biogenic and anthropogenic organic compounds, as well as the chemistry of secondary species, and to propose improvements for integration into CHIMERE.
Responsibilities
Carry out a state-of-the-art study on the representation of organic carbon evolution in models.
Develop 0D scenarios to represent the measurement sites of the ACROSS and EMEP campaigns.
Carry out explicit 0D simulations for the various measurement sites.
Select and format the measurements of interest from the ACROSS and EMEP campaigns, in particular VOCs.
Make explicit model/detailed measurements comparisons and evaluate the model.
Identify the origin of observed discrepancies and suggest improvements.
Run 0D simulations with reduced mechanisms for the various measurement sites.
Make comparisons between reduced mechanisms/explicit model/detailed measurements.
Select the most reliable reduced mechanism to represent the formation of secondary pollutants.
Run CHIMERE simulations for the summer of 2022, following these improvements.
Carry out model/measurement comparisons and evaluate the model.
Analyze the contribution of anthropogenic and biogenic sources to the formation of secondary pollutants and the dependence on meteorological conditions.
Present results at ECLAT project meetings.
Promote work at international conferences and write scientific articles.
This position will be based at LISA (Laboratoire Interuniversitaire des Systèmes Atmosphériques), within the MODELISATION group. The work will be carried out as part of the ÉCLAT project, funded by ADEME and led by Matthias Beekmann (DR CNRS). The person recruited will benefit from LISA's strong expertise in 0D modelling and explicit chemical mechanisms and expertise in 3D modelling and reduced mechanisms, with the contribution of a dynamic scientific support team.
PhD in atmospheric sciences, environmental sciences, chemistry or related disciplines.
Experience in chemical modeling, ideally of atmospheric chemical composition.
Excellent knowledge of scientific programming (R, Python, Fortran…).
Expertise in Linux environment.
Rigor, autonomy and scientific curiosity.
Initiative, synthesis and critical analysis skills.
Good teamwork skills.
Writing and verbal skills in English.
Additional comments
LISA is a joint research unit of Université Paris-Est Créteil, Université Paris Cité and CNRS. Its main research themes focus on understanding the functioning of terrestrial and planetary atmospheres, and the impacts of human activities on atmospheric composition.
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