|From||Roger Brugge <email@example.com>|
|Date||Thu, 12 Apr 2018 18:26:52 +0000|
Today, more than 70% of fossil fuel CO2 emissions are estimated to come from urbanized and industrialized areas that represent less than 3% of the terrestrial surface. These areas are thus specifically of interest regarding emission mitigation strategies. Current emission inventories estimate that the Provence Alpes Côte d’Azur (PACA) region, in the South-East of France, represents 10% of the national CO2 fossil fuel emissions, with a high density of emissions in the Aix-Marseille metropolis area. Inventories are based on the product of emission factors (e.g. the amount of CO2 emitted by kilometer) and of activity estimates by sector (e.g. number of kilometers performed by the vehicle float on the studied area). However, the uncertainties on the regional CO2 emissions are large and can reach several tens of percents for some activity sectors (Rayner et al, 2012). Furthermore, these emissions lead to local to regional CO2 concentrations that are relatively high compared to non urbanized areas, and that could have impacts on the surrounding ecosystems (forests, soils, cultures, coastal sea…) that are still unknown today. These local to regional impacts come on top of those of the global climate change to which the PACA region is highly exposed (IPCC, 2013), and therefore, they must be carefully studied. Today, it is thus necessary to study all the components of the carbon cycle of the PACA region (anthropogenic, biospheric and oceanic) with a fourfold objective :
The atmospheric approach, based on a synergy between measurements and modeling of atmospheric CO2 at the mesoscale, represents a method of choice to improve our knowledge of the carbon cycle in anthropogenized regions. Such approach has been developed successfully in France (Xueref-Remy et al, 2018 ; Ammoura et al, 2016 ; Lopez et al, 2013 ; Lac et al, 2013) to verify the emissions inventory of the Paris megacity region. It has also been tested in other urbanized and industrialized regions of the world, like those of Los Angeles and Indianapolis (e.g. Turnbull et al, 2015). In the framework of the OT-MED AMC project (2016-2019, http://www.otmed.fr/observation-systems-and-databases/aix-marseille-carbon-pilot-study-amc), we are developing such an atmospheric approach that will allow us to assess the emission estimates delivered by Air PACA, the agency of air quality monitoring in the PACA region.
The candidate will work on the acquisition, on the treatment, on the calibration and on the analysis of the CO2 and CO data collected since July 2016 at 4 different sites of the region, each site being more or less anthropogenized (urban/coastal/peri-urban/rural). Based on a wind classification, the phD student will assess the role of remote emissions and fluxes vs regional ones at the diurnal, synoptic and seasonal scales (e.g. Xueref-Remy et al, 2018). Furthermore, he/she will also perform field measurements to collect air samples for radiocarbone analysis of the content of CO2, and will calculate the partitioning of the fossil fuel emissions vs modern fluxes at the different observation sites (e.g. Lopez et al, 2013 ; Turnbull et al, 2015), in summertime and in wintertime. These results will be compared to those obtained with atmospheric transport modeling tools conducted by a postdoctorate fellow within the AMC project. The results obtained by the phD student will allow for the first time : 1/ to quantify the CO2 urban plume outcoming from the Aix-Marseille metropolis ; 2/ to assess independently the emissions inventory of Air PACA ; and 3/ to calculate the CO2 budget components in the area of the Aix-Marseille metropolis. The exposition of the surrounding ecosystems to the Aix-Marseille CO2 urban plume will be characterized and will allow starting in parallel to this phD work some collaborations on the impact of the Aix-Marseille emissions on surrounding coastal and terrestrial ecosystems, together with ecologists and oceanographers from the AMC project. The progresses and results of this phD work will be communicated via the GREC-PACA association (http://www.grec-paca.fr/), which is a partner of this project, to the territorial collectivities and stakeholders of the PACA region.
Profile of the candidate : the student must be holder of a diploma of Master of Sciences before the summer 2018 and must have a solid knowledge in Environnemental Sciences, Atmospheric Physics and/or Atmospheric Chemistry.
Ammoura, L., Xueref-Remy, I., Vogel, F., Gros, V., Baudic, A., Bonsang, B., Delmotte, M., Té, Y., and Chevallier, F. (2016) Exploiting stagnant conditions to derive robust emission ratio estimates for CO2, CO and volatile organic compounds in Paris, Atmos. Chem. Phys., 16, 15653-15664, doi:10.5194/acp-16-15653-2016.
IPCC (Intergovernmental Panel on Climate Change), Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 1535 pp, doi:10.1017/CBO9781107415324, 2013.
Lac, C., R.P. Donnelly, V. Masson, S. Pal, S. Riette, S. Donier, S. Queguiner, G. Tanguy, L. Ammoura and I. Xueref-Remy (2013), CO2 dispersion modelling over Paris region within the CO2-MEGAPARIS project, Atmos. Chem. Phys., 13, 4941-4961, doi:10.5194/acp-13-4941-2013.
Lopez, M., Schmidt, M., Delmotte, M., Colomb, A., Gros, V., Janssen, C., Lehman, S. J., Mondelain, D., Perrussel, O., Ramonet, M., Xueref-Remy, I. and P. Bousquet (2013), CO, NOx and 13CO2 as tracers for fossil fuel CO2 : results from a pilot study in Paris during winter 2010, Atmos. Chem. Phys.,, 13, 7343–7358, doi:10.5194/acp-13-7343-2013.
Rayner, P. J., M. R. Raupach, M. Paget, P. Peylin, and E. Koffi, A new global gridded data set of CO2 emissions from fossil fuel combustion: Methodology and evaluation, J. Geophys. Res., 115, D19306, doi:10.1029/2009JD013439, 2012.
Turnbull, J. C., et al. (2015), Toward quantification and source sector identification of fossil fuel CO2 emissions from an urban area: Results from the INFLUX experiment, J. Geophys. Res. Atmos., 120, 292–312, doi:10.1002/2014JD022555.
Xueref-Remy, I., E. Dieudonné, C. Vuillemin, M. Lopez, C. Lac, M. Schmidt, M. Delmotte, F. Chevallier, F. Ravetta, P. Ciais, F.-M. Bréon, G. Broquet, O. Perrussel, M. Ramonet, T. G. Spain and C. Ampe (2018), Diurnal, synoptic and seasonal variability of atmospheric CO2 in the Paris megacity area, Atmos. Chem. Phys., 18, 3335-3362, doi:10.5194/acp-18-3335-2018
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