(M/F) : researcher : Modelling organic carbon in a context of climate change: how reliable are the models?

id="offer-description" class="ecl-u-type-heading-2 ecl-u-mt-none ecl-u-mb-l">Offer Description Volatile organic compounds (VOCs) in the atmosphere have an impact on air quality and climate, and are precursors for the photochemical formation of secondary pollutants such as ozone and fine organic particles. The complex chemistry of VOC oxidation can be explicitly represented, with millions of reactions, in highly detailed chemical mechanisms generated with the LISA GECKO-A tool ( https://geckoa.lisa.u-pec.fr ). However, it is represented in a very simplified way, with a few hundred reactions, in the reduced chemical mechanisms commonly used in chemistry and transport models. This post-doctoral project aims to assess the ability of reduced chemical mechanisms to represent concentrations of gaseous compounds, and in particular those of VOCs and radicals, in a context of climate change. The method will consist of comparing in a box model several reduced mechanisms (MELCHIOR, SAPRC-07, SAPRC-22) which are currently used in the chemistry and transport model CHIMERE ( https://www.lmd.polytechnique.fr/chimere/ ) to an explicit reference mechanism generated by GECKO-A. The simulations will focus on France during the summer of 2022, which is characterized by several hot periods, and can thus be used as an analogue of a future climate. Discrepancies in the predictions of the mechanisms will be documented for ozone, nitrogen oxides and radicals, as well as for the reactivity of VOCs with