Periodic Reporting for period 1 - DUSC3 (DUSt, Climate and Carbone Cycle)
Période du rapport: 2016-12-01 au 2018-11-30
Mineral (desert) dust is the most abundant aerosol by mass in present day atmosphere, and contributes to about one quarter of the total extinction of sunlight by aerosols, including anthropogenic aerosols. Dust is emitted from sparsely vegetated lands by the action of wind erosion. Changing climatic conditions, as well as land cover and land use changes, have altered dust emissions in the past as much as by a factor five over vast areas of the globe, and may cause significant changes in dust emissions in the future. Because of dust impacts on economical activities, air quality and climate it is important that we are able to understand and predict changes in the global dust cycle. DUSC3 produces an updated view of the global dust cycle, by integrating a collection and re-interpretation of paleodust archives with novel simulations with the IPSL Earth system model, which is used to estimate impacts of dust on climate.
A collection and re-interpretation of paleodust archives organized in an innovative and coherent way provides a constraint on the variability of the dust cycle since the last interglacial period (~130,000 years ago). Novel simulations with the IPSL Earth system model are carried out after several improvements in the representation of the key aspects in the model, such as dust emissions, particle size distributions and optical properties. An overview of the state of the art on aerosol interactions with climate during glacial climates is already published in Current Climate Change Reports. Several preliminary results linked to manuscripts in preparation have been presented at six international conferences and workshops.
The paleodust database constitutes a synthesis effort with benefits for the broader community well beyond the scopes of this project. It allows evaluating the state of the art in reconstructing the global dust cycle and highlighting current limitations and pitfalls, pointing directions for further research. It is of relevance for informing the IPCC AR6 on the state of this component of the climate system. The model improvements and inclusion of new processes contributes to the development of the IPSL-ESM, which is one of the major contributors to the CMIP experiments.