* The seminar will be in English, the event is open to the public.

Abstract
Despite the unique scientific value of better knowing atmospheric composition over Siberia, regional observations of the tropospheric composition over this region are still lacking. Large local anthropogenic emissions, strong ecosystem gas exchange across the vast forest expanse, and processes feeding back to global climate such as wetlands CH4 emissions, seabed hydrates destabilization and degrading permafrost make this region particularly crucial to investigate.
We aim at addressing this need in the YAK-AEROSIB program by collecting high-precision in-situ measurements of the vertical distribution of CO2, CH4, CO, O3, black carbon and ultrafine particles distribution in the Siberian troposphere, as well as other parameters including aerosol lidar profiles, on a pan-Siberian aircraft transect. Campaigns are performed annually on this regular route, while special campaigns are occasionally arranged to sample the troposphere elsewhere (e.g. Russian Arctic coast).
We find background tropospheric condition clean relative to the general Northern Hemisphere. The variability and the impact of large-scale transport of anthropogenic emissions from Europe and Asia, as well as the impact of biomass burning plumes both from local wildfires and from remote sources elsewhere in Asia have been documented. Long range transport of anthropogenic emissions is shown to have a discernible impact on O3 distribution, although its lower-tropopsheric variability is largely driven by surface deposition. Regional sources and sinks drive the lower troposphere CO2 and CH4 concentrations. Recent efforts aim at better understanding the respective role of CH4 emission processes in driving its large scale atmospheric variability over the region. The challenging question of methane budget and its evolution in Siberia leads to a need for new approaches. A new generation of airborne measurements, more flexible, is now needed.


About the Speaker
Dr. Jean-Daniel Paris is with the Climate and environmental sciences laboratory (LSCE), a joint laboratory of the French Atomic Energy Commission (CEA), CNRS and Université de Versailles Saint Quentin (UVSQ). He received his PhD from UVSQ in 2008 on greenhouse gases observations from aircraft. Earlier, he worked at the European Space Agency on the design of future Earth observation missions. His research interests are related to climate, environmental sciences and research infrastructures, focusing on the carbon cycle and atmospheric chemistry. He is since 2008 the coordinator of the French-Russian YAK-AEROSIB atmospheric measurement program in Siberia, and has been chief field scientist for 3 multi-instrumented large aircraft campaigns. He coordinated the EU FP7 project ICOS-INWIRE, researching solutions for enhanced measurements and data chains from the field to users within the European greenhouse gas measurement Research Infrastructure ICOS (Integrated Carbon Observing System). He teaches at the International Arctic Master programme of UVSQ.