Dmitry Koshelev Yao T Pascal Jeseck Irne XuerefRemy

Dmitry Koshelev, Yao Té, Pascal Jeseck, Irène Xueref-Remy, François Ravetta and Christof Janssen TCCON MEASUREMENTS IN THE PARIS MEGAPOLIS 1

TCCON: FTS-Paris instrument o Sun. Traker o FTIR Spectrometer - Bruker 125 HR Resolution: 0. 019 cm-1 (OPD = 45 cm) 2

TCCON: FTS-Paris instrument o Sun. Traker o FTIR Spectrometer - Bruker 125 HR Resolution: 0. 019 cm-1 (OPD = 45 cm) Moving mirror Detector Beamsplitte r Fixed mirror 3

TCCON: FTS-Paris instrument o Sun. Traker o FTIR Spectrometer - Bruker 125 HR Resolution: 0. 019 cm-1 (OPD = 45 cm) Moving mirror Detector Beamsplitte r Fixed mirror 4

Gas concentration retrieval Radiance at ground level Radiance at top atmosphere Atmospheric transmission concentration • Atmospheric transmission contains all information about gas abundances 5

GFIT code • GFIT – nonlinear least-squares fitting algorithm used by all TCCON sites • GFIT computes column abundances from the solar absorption spectra. H 2 O micro window Full spectra (2500 - 14000 cm-1) CO 2 micro window 6

Dry air mole fraction (DMF) • 7

Dry air mole fraction (DMF) • 8

GFIT code in urban area? o. GFIT has been developed for all TCCON sites o. Two sites in urban area: Paris and Los Angeles o. How does it work in a urban area? 9

• GFIT: a priori profiles of CO The GFIT algorithm scales an a priori 2 profile to generate the best spectral fit and integrates the scaled profile to compute the column abundances GFIT a priori profile of CO 2 10

Sensitivity of GFIT to a priori • The GFIT algorithm scales an a priori profile to generate the best spectral fit and integrates the scaled profile to compute the column abundances 11

Modified a priori profiles • In situ CO 2 vs a priori GFIT ground value Set of a priori profiles 12

Modified a priori profiles Set of a priori profiles Comparison of XCO 2 retrieved with different profiles 13

Modified a priori profiles: residue Profile χ2 Standard (412) 2. 65288 E-5 390 2. 66659 E-5 400 2. 65995 E-5 410 2. 65395 E-5 420 2. 64856 E-5 430 2. 64378 E-5 440 2. 6396 E-5 450 2. 63603 E-5 460 2. 63305 E-5 470 2. 63066 E-5 480 2. 62886 E-5 490 2. 62763 E-5 500 2. 62698 E-5 510 2. 62689 E-5 520 2. 62737 E-5 14

• GFIT a priori profiles including ABL LIDAR – Height of Planetary Boundary Layer PBL In situ 15

GFIT a priori profiles including ABL • GFIT modified a priori profiles In situ CO 2 Profile χ2 Standard 2. 65288 E-5 440 2. 63591 E-5 460 2. 63092 E-5 480 2. 63141 E-5 16

Next steps • • Study impact of polluted boundary layer Selected days: 20/01/2016 and 18/04/2016 and two summer days are pending ABL: about 200 m ABL: 600 m @08: 00 1300 m @10: 00 1800 m @14: 00 17

THANK YOU 18

Next steps • Selected days: 20/01/2016 and 18/04/2016 and two summer days are pending. • Air mass movement for selected days 19

Paris TCCON data 09/2014 – 11/2016 Other molecules: HF, H 2 O, HDO 20