Accueil > Actualités > Soutenances de thèse ou de HDR > Soutenance de thèse de Dmitry KOSHELEV au LERMA



Titre : First ground based FTIR-TCCON measurements of CO2 in a European megacity: comparison with a rural site and validation of satellite measurements

Date et heure : Le 11-10-2018 à 14h00

Type : thèse

Université qui délivre le diplôme : Sorbonne Universtité

Lieu : Campus de Jussieu, Amphithéâtre HERPIN, Bâtiment Esclangon
Membres du jury :

Mme ROTGER Maud, GSMA, rapporteure

M. WARNEKE Thorsten, IUP de Brême, rapporteur

M. RAMONET Michel, LSCE-IPSL, examinateur

Mme DE MAZIERE Martine, BIRA-IASB, examinatrice

Mme. PICON Laurence, LMD-IPSL, examinatrice

M. JANSSEN Christof, LERMA, Directeur de thèse

Résumé :

The Total Carbon Column Observing Network (TCCON) is a global network of ground-based Fourier transform spectrometers that monitor column-averaged abundances of atmospheric greenhouse gases by direct solar absorption spectroscopy. The TCCON-Paris station is located in the centre of Paris and is the first site operating in a European megacity.

The manuscript first describes the instrument and its performance. The instrumental line shape is investigated by using low-pressure HCl gas cell measurements. The instrument stability is determined using the Allan variance approach and we have participated in a blind intercomparison of N2O gas columns in low-pressure cells. The results of our analysis have helped to identify an error in the reference measurements. Then, we discuss data acquisition and retrieval. Different acquisition parameters are compared in order to improve the precision of the Paris measurements. The GGG retrieval software and its quality control procedure and built-in filters for TCCON are discussed.

We investigate, in as much a priori profiles provided by GGG are suited to retrieve CO2 abundances in Paris by comparing with retrievals based on local atmospheric conditions obtained from CO2 in-situ and LIDAR boundary layer measurements. An overview of the method using the improved CO2 a priori profiles is given and the sensitivity and biases of the retrieved CO2 columns compare discussed.

Mobile, low-resolution instruments (EM27/SUN) can be used for intercalibrating distant TCCON instruments. One such EM27/SUN instrument was used to compare the TCCON sites at Orleans and Paris. Small differences between instruments and sites were observed and are discussed.

Contact :
Retour à la liste soutenances de thèse ou de hdr