“…Lagrangian studies reconstruct SWV by tracking the minimum saturation mixing ratio of air at the Lagrangian dry point (LDP) (Fueglistaler and Haynes, 2005;Liu;Schoeberl and Dessler, 2011;Smith et al, 2021). We combine airborne in situ measurements during the StratoClim campaign in Nepal (Lauther et al, 2021) with satellite observations of MLS (Livesey et al, 2020) and CALIPSO (Vaughan et al, 2009) to investigate the representativeness of the moist air masses encountered above the CPT for the large-scale SWV distribution. Using forward trajectories and a microphysical model, we address two main questions: (i) How does the water vapor content of these air masses change during their ascent into the stratosphere?…”