Upper tropospheric water vapor profiles derived from Raman lidar over France territories for contrail investigations

Dunya Alraddawi; Philippe Keckhut; Florian Mandija; Alexis Mariaccia; Christophe Pietras; Jean-Charles Dupont; Guillaume Payen; Hélène Vérèmes; Alain Hauchecorne; Alain Sarkissian; Jean-François Mariscal; Jacques Porteneuve; Jean-Luc Baray; Nadège Montoux; Patrick Fréville; Sergey Khaykin

doi:10.1051/epjconf/202636209011

Open Access

Issue		EPJ Web Conf. Volume 362, 2026 31^st International Laser Radar Conference (ILRC 31) Held Together with the 22^nd Coherent Laser Radar Conference (CLRC 22)


Article Number		09011
Number of page(s)		4
Section		Lidar Measurements of Trace Gases (including Greenhouse Gases and Water Vapour)
DOI		https://doi.org/10.1051/epjconf/202636209011
Published online		09 April 2026

EPJ Web of Conferences 362, 09011 (2026)
https://doi.org/10.1051/epjconf/202636209011

Upper tropospheric water vapor profiles derived from Raman lidar over France territories for contrail investigations

Dunya Alraddawi^(a), Philippe Keckhut^(a), Florian Mandija^(a), Alexis Mariaccia^(a), Christophe Pietras^(b), Jean-Charles Dupont^(c), Guillaume Payen^(d), Hélène Vérèmes^(d), Alain Hauchecorne^(a), Alain Sarkissian^(a), Jean-François Mariscal^(a), Jacques Porteneuve^(e), Jean-Luc Baray^(f), Nadège Montoux^(f), Patrick Fréville^(g) and Sergey Khaykin^(a)

^(a) LATMOS-IPSL, UMR8190, UVSQ – UPMC – CNRS, Guyancourt, France
^(b) Laboratoire de Météorologie Dynamique, École Polytechnique, CNRS, Palaiseau, France
^(c) Institut Pierre-Simon Laplace, École Polytechnique, UVSQ, Université Paris-Saclay, Palaiseau, France
^(d) LACy, UMR8105, CNRS – Université de la Réunion – Météo-France, Réunion, France
^(e) Gordien Strato, Verrière le buisson, France
^(f) LaMP, UMR6016, Université Clermont Auvergne – CNRS, Clermont-Ferrand, France
^(g) OPGC, UAR833, Université Clermont Auvergne – CNRS, Clermont Ferrand, France This email address is being protected from spambots. You need JavaScript enabled to view it.

Published online: 9 April 2026

Abstract

Accurate water vapor measurements in the upper troposphere at cruise altitude are required to investigate contrails formation. We present 4 Raman lidars having these capabilities in France. Water vapor mixing ratio is proportional to the ratio of H2O and N2 Raman signals for the same altitude by a scale factor called calibration factor. Coaxial systems can be calibrated with independent measurement of water vapor total column. A more universal external method able to calibrate any lidar (co/non-axial system) is adopted, using co-located ERA5 hourly water vapor profiles. Full night calibration factor is estimated as the mean of hourly coefficients, daily calibrations are inspected to detect any instrumental changes. Final coefficients are then considered for quasi stationary periods. Calibrated profiles are validated against available radiosondes ones. This new software can be used to force models to better understand contrails contribution in future air traffic regulation as part of European project BeCoM.

This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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