Titre :

Derivation of depolarization ratios of aerosol fluorescence and water vapor Raman backscatters from lidar measurements

Auteur(s) :

Veselovskii, Igor [Auteur]
Hu, Qiaoyun [Auteur]
Laboratoire d'Optique Atmosphérique (LOA) - UMR 8518
Goloub, Philippe [Auteur]
Laboratoire d'Optique Atmosphérique (LOA) - UMR 8518
Podvin, Thierry [Auteur]
Laboratoire d'Optique Atmosphérique (LOA) - UMR 8518
Boissiere, William [Auteur]
Laboratoire d'Optique Atmosphérique (LOA) - UMR 8518
Korenskiy, Mikhail [Auteur]
Kasianik, Nikita [Auteur]
Khaykyn, Sergey [Auteur]
TROPO - LATMOS
Robin, Miri [Auteur]
Laboratoire d’Optique Atmosphérique - UMR 8518 [LOA]

Titre de la revue :

Atmospheric Measurement Techniques

Nom court de la revue :

Atmos. Meas. Tech.

Numéro :

17

Pagination :

1023-1036

Éditeur :

Copernicus GmbH

Date de publication :

2024-02-12

ISSN :

1867-8548

Discipline(s) HAL :

Planète et Univers [physics]

Résumé en anglais : [en]

Abstract. Polarization properties of the fluorescence induced by polarized laser radiation are widely considered in laboratory studies. In lidar observations, however, only the total backscattered power of fluorescence is ...
Lire la suite >Abstract. Polarization properties of the fluorescence induced by polarized laser radiation are widely considered in laboratory studies. In lidar observations, however, only the total backscattered power of fluorescence is analyzed. In this paper we present results obtained with a modified Mie–Raman–fluorescence lidar operated at the ATOLL observatory, Laboratoire d'Optique Atmosphérique, University of Lille, France, allowing us to measure depolarization ratios of fluorescence at 466 nm (δF) and of water vapor Raman backscatter. Measurements were performed in May–June 2023 during the Alberta forest fires season when smoke plumes were almost continuously transported over the Atlantic Ocean towards Europe. During the same period, smoke plumes from the same sources were also detected and analyzed in Moscow, at the General Physics Institute (GPI), with a five-channel fluorescence lidar able to measure fluorescence backscattering at 438, 472, 513, 560 and 614 nm. Results demonstrate that, inside the planetary boundary layer (PBL), the urban aerosol fluorescence is maximal at 438 nm, and then it gradually decreases with the increase in wavelength. The smoke layers observed within 4–6 km height present a maximum fluorescence at 513 nm, while in the upper troposphere, fluorescence maximum shifts to 560 nm. Regarding the fluorescence depolarization ratio, for smoke its value typically varies within the 45 %–55 % range. The depolarization ratio of the water vapor Raman backscattering at 408 nm is shown to be quite low (2±0.5 %) in the absence of fluorescence because the narrowband interference filter (0.3 nm) in the water vapor channel selects only the strongest vibrational lines of the Raman spectrum. As a result, the depolarization ratio at the water vapor Raman channel is sensitive to the presence of strongly depolarized fluorescence backscattering and can be used for the evaluation of the aerosol fluorescence contribution to measured water vapor mixing ratio.Lire moins >

Comité de lecture :

Oui

Audience :

Internationale

Vulgarisation :

Non

Établissement(s) :

Université de Lille
CNRS

Collections :

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

Équipe(s) de recherche :

Interactions Aérosols Rayonnement (IAR)

Date de dépôt :

2024-02-13T09:27:49Z
2024-02-23T10:39:25Z