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PhD Defense

Abdelhadi EL YAZIDI (LSCE)

Title : Estimation des flux de CO2 et de CH4 en France en utilisant les concentrations atmosphériques du réseau ICOS et les techniques d'assimilation de données

Date and time : The 01-10-2018 at 14h00

Type : thèse

Université qui délivre le diplôme : UVSQ

Location : Salle Galilée Bat 713, LSCE, CEA Saclay, Orme des Merisiers 91191 Gif sur Yvette
Members of jury :

M. Philippe CIAIS, Professeur, LSCE, FRANCE - Directeur de these

M. Christoph GERBIG, Professeur, Max Planck Institute for Biogeochemistry, ALLEMAGNE - Rapporteur

Mme Greet JANSSEN-MAENHOUT, Professeur, European Commission, Joint Research Centre (EC-JRC), ITALIE - Rapporteur

M. Michel RAMONET, Professeur, LSCE, FRANCE - CoDirecteur de these

Mme Christine LAC, Professeur, CNRM, FRANCE - Examinateur

M. Vincent-Henri PEUCH, Professeur, ECMWF, ROYAUME-UNI - Examinateur

M. Philippe BOUSQUET, Professeur, LSCE, FRANCE - Examinateur

Summary :

Since the industrial revolution, the economic and the demographic growths have increased exponentially, leading to an enhancement of the fossil fuels combustion, such as coal, oil, and natural gas. Consuming these source of energy lead to the amplification of the greenhouse gas emissions, mainly carbon dioxide (CO2) and methane (CH4), which with their accumulation in the atmosphere lead to the increase of the greenhouse effect. According to the 5th assessment report of the IPCC (Intergovernmental Panel on Climate Change), it is extremely likely (95-100% of certainty) that the observed increase in the greenhouse effect is related to the increase of the anthropogenic emissions. However, the estimations of the GHG budget at the regional scale remains very uncertain. The aim of this thesis is to improve the estimation of GHG emissions in France, using for the first time the atmospheric observation provide by the ICOS (Integrated Carbon Observation System) network and inverse modeling at the regional scale First, we focus on analyzing the measured CO2, CH4, and CO (Carbon monoxide) atmospheric concentrations provided by surface stations. This study concerns the problem of identifying atmospheric data influenced by local emissions that can result in spikes in time series of greenhouse gases (GHG) and long-lived tracer measurements. Three methods are applied on continuous time series of four contrasted atmospheric sites. The spikes detected by the three methods are compared to each other and then to the data detected manually by sites manager. The aim of this comparison is to quantify the percentage of the contaminated data for each site and to evaluate the performance of the used methods for the correct detection. This work allows us to select the most reliable method that will be proposed to perform daily spike detection in the ICOS Atmospheric Thematic Centre Quality Control (ATC-QC) software. Second, we simulate the atmospheric concentrations of CO2 and CH4 using the chemistry transport model CHIMERE in a domain centered over France for the year 2014. The objective of this study is to study the sensitivity of simulated concentrations using different input data. First, we evaluate the sensitivity of simulated concentrations to transport field using the two meteorological models AROME and ECMWF. Then, we investigate the sensitivity of the simulated CO2 and CH4 concentrations regarding different emission fluxes. In this later step, the study is performed by investigating separately the anthropogenic and the biogenic fluxes. This work lead to the quantification of both the transport and surface fluxes errors. The combination of the best input data is selected for the flux inversion study. Lastly, the measured CO2 and CH4 concentrations are used by the PYMAI inversion system (Berchet et al., 2013 and 2015) in order to estimate the GHG emissions in France. The Inversion is performed for one month in winter (January) and one month in summer (July), using the transport model CHIMERE forced by ECMWF, and EDGAR and VPRM surface fluxes as a prior. On one hand, this work leads to an uncertainty reduction of the national emission by a percentage that attains 35% compared to the prior. On the other hand, the used inversion system constrain only partially the emission fluxes. This result opens the debate about the efficiency of the amount of information available, and the actions to take to better constrain the surface fluxes.

Contact :
abdelhadi.el-yazidi@lsce.ipsl.fr
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