Title :

Profiling of ch4 background mixing ratio in the lower troposphere with raman lidar: a feasibility experiment

Author(s) :

Veselovskii, Igor [Auteur]
A. M. Prokhorov General Physics Institute [GPI]
Goloub, Philippe [Auteur]
Laboratoire d'Optique Atmosphérique (LOA) - UMR 8518
Hu, Qiaoyun [Auteur]
Laboratoire d’Optique Atmosphérique - UMR 8518 [LOA]
Podvin, Thierry [Auteur]
Laboratoire d’Optique Atmosphérique - UMR 8518 [LOA]
Whiteman, David N. [Auteur]
NASA Goddard Space Flight Center [GSFC]
Korenskiy, Mikhael [Auteur]
A. M. Prokhorov General Physics Institute [GPI]
Landulfo, Eduardo [Auteur]
Instituto de Pesquisas Energéticas e Nucleares [São Paulo] [IPEN/CNEN-SP]

Journal title :

Atmospheric Measurement Techniques

Abbreviated title :

Atmos. Meas. Tech.

Volume number :

12

Publication date :

2019-01-07

ISSN :

1867-1381

HAL domain(s) :

Physique [physics]

English abstract : [en]

We present the results of methane profiling in the lower troposphere using LILAS Raman lidar from the Lille University observatory platform (France). The lidar is based on a frequency-tripled Nd:YAG laser, and nighttime ...
Show more >We present the results of methane profiling in the lower troposphere using LILAS Raman lidar from the Lille University observatory platform (France). The lidar is based on a frequency-tripled Nd:YAG laser, and nighttime profiling up to 4000 with 100 m height resolution is possible for methane. Agreement between the measured photon-counting rate in the CH4 Raman channel in the free troposphere and numerical simulations for a typical CH4 background mixing ratio (2 ppm) confirms that CH4 Raman scattering is detected. The mixing ratio is calculated from the ratio of methane (395.7 nm) and nitrogen (386.7 nm) Raman backscatters, and within the planetary boundary layer, an increase of the CH4 mixing ratio, up to a factor of 2, is observed. Different possible interfering factors, such as leakage of the elastic signal and aerosol fluorescence, have been taken into consideration. Tests using backscattering from clouds confirmed that the filters in the Raman channel provide sufficient rejection of elastic scattering. The measured methane profiles do not correlate with aerosol backscattering, which corroborates the hypothesis that, in the planetary boundary layer, not aerosol fluorescence but CH4 is observed. However, the fluorescence contribution cannot be completely excluded and, for future measurements, we plan to install an additional control channel close to 393 nm, where no strong Raman lines exist and only fluorescence can be observed.Show less >

Language :

Anglais

Audience :

Internationale

Popular science :

Non

Administrative institution(s) :

CNRS
Université de Lille

Collections :

• Laboratoire d'Optique Atmosphérique (LOA) - UMR 8518

Submission date :

2024-01-30T11:45:48Z
2024-02-21T09:15:34Z