Lidar ratio calculations from in situ aerosol optical, microphysical and chemical measurements: Observations at puy de Dôme, France and analysis with CALIOP - INSU - Institut national des sciences de l'Univers Accéder directement au contenu
Article Dans Une Revue Atmospheric Research Année : 2023

Lidar ratio calculations from in situ aerosol optical, microphysical and chemical measurements: Observations at puy de Dôme, France and analysis with CALIOP

Résumé

The ratio between lidar extinction and backscatter coefficients, also known as lidar ratio (LR), is an important parameter in atmospheric aerosol studies. In this paper, we propose a method to determine the 532 nm LR using in situ measurements performed over the 2015–2016 period at the puy de Dôme (PUY) station, central France, located at about 1465 m altitude. This method uses a Mie code with the measured aerosols size distribution and refractive index determined from aerosols optical measurements as inputs. The LR values obtained have been compared to LR calculated also with a Mie code but with refractive index determined from the measured aerosol chemical composition. A good correlation is observed for the period 2015–2016 with an agreement which increases to 99% after a significant imaginary part refractive index reduction, corresponding to much less carbonated particles than initially estimated. >50% of the LR values calculated at the station are within the 60–80 sr range under ambient atmospheric conditions. A statistical comparison with the CALIOP spatial lidar retrieval gives a good agreement at the location of PUY between retrieved values (62 sr) with a negligible bias and a dispersion indicative of a similar variability of LR (about 14 sr). The influence of air mass history on the LR has also been studied using backward trajectory analysis and CALIOP aerosol types along the trajectories, identifying five source regions. For continental, smoke and polluted dust aerosols types, CALIOP and PUY LR show a good agreement. For dusty and mainly clean marine aerosols, the differences observed between both suggest that air masses coming from the Atlantic Ocean sector at altitudes lower than 2.5 km, have experienced mixing with continental air masses during their travel increasing their LR before reaching the PUY station.
Fichier principal
Vignette du fichier
1-s2.0-S0169809523004404-main.pdf (7.74 Mo) Télécharger le fichier
Origine : Fichiers éditeurs autorisés sur une archive ouverte
Licence : CC BY - Paternité

Dates et versions

insu-04232928 , version 1 (29-10-2023)

Identifiants

Citer

Kruthika Eswaran, Nadège Montoux, Aurélien Chauvigné, Jean-Luc Baray, Gérard Ancellet, et al.. Lidar ratio calculations from in situ aerosol optical, microphysical and chemical measurements: Observations at puy de Dôme, France and analysis with CALIOP. Atmospheric Research, 2023, 296 (December), pp.107043. ⟨10.1016/j.atmosres.2023.107043⟩. ⟨insu-04232928⟩
117 Consultations
10 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More