PhD Thesis: Characterization of the physical and ice-nucleating properties of sea spray (M/F)

Job Description

Thesis Subject

Context and Objectives: The oceans cover more than two-thirds of the Earth's surface and largely dominate the Southern Hemisphere. The marine atmosphere is therefore an essential component of the climate system. Marine aerosols, emitted by wave action as droplets are produced when bubbles burst at the air-sea interface, persist in the atmosphere as sea spray aerosols (SSA). These particles influence the climate both directly, by interacting with solar radiation, and indirectly, by acting as cloud condensation nuclei (CCNs) and ice nucleating particles (INPs). The lack of understanding of natural aerosol emission processes, of which marine aerosols are a major contributor, and their interaction with clouds, is the source of much of the uncertainty in aerosol forcing on climate. In the Southern Ocean in particular, there is a significant warming bias in global models. The causes of this bias have been attributed to the excessively short lifetime of clouds in this region of the world, likely linked to a failure to accurately represent sea spray aerosols and their CCN (cloud condensation nuclei) and INP (ice-nucleating particle) properties. However, sea spray emissions and their hygroscopic properties depend on the oceanic biosphere. This doctoral thesis aims to investigate the factors influencing sea spray emission processes in the Southern and Antarctic Oceans, as well as the factors affecting their ice-nucleating properties. Methodology: Sea spray will be generated during oceanographic campaigns aboard research vessels and characterized in terms of number distribution and ice-nucleating properties. Relationships between sea spray and ice-nucleating particle fluxes will be compared against physical seawater variables (temperature, salinity, etc.) and biogeochemical properties. The two planned oceanographic campaigns are MISO2, aboard the Australian research vessel *Investigator*, and ASOLAS, aboard the German research vessel *Polarstern*. Other datasets are also available for comparison, such as those sampled in the Weddell Sea (near Antarctica) as part of the POLARCHANGE project, or in the French Southern and Antarctic Lands (TAAF).

Your Work Environment

The thesis will be based at Laboratoire de Météorologie de Clermont-Ferrand when not in the field

Constraints and risks

The candidate will be required to embark on research vessels for several months and/or stay in the French Southern and Antarctic Lands, and must therefore have an affinity for fieldwork in isolated and sometimes hostile environments.

Compensation and benefits

Compensation

2300 € gross monthly

Annual leave and RTT

44 jours

Remote Working practice and compensation

Pratique et indemnisation du TT

Transport

Prise en charge à 75% du coût et forfait mobilité durable jusqu’à 300€

About the offer

About the CNRS

The CNRS is a major player in fundamental research on a global scale. The CNRS is the only French organization active in all scientific fields. Its unique position as a multi-specialist allows it to bring together different disciplines to address the most important challenges of the contemporary world, in connection with the actors of change.

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