The abundance, vertical distribution and origin of H2O in Titan's atmosphere: Herschel observations and photochemical modelling

► Measurements of H2O rotational lines were performed with the Herschel/PACS and the Herschel/HIFI instruments. ► Semi-empirical water vertical profiles are derived over the 100-450 km altitude range. ► Photochemical models of oxygen species in Titan's atmosphere are reconsidered. ► The constrained OH/H2O influx is of (2.7-3.4) × 105 mol cm−2 s−1. ► Both interplanetary dust particles and Enceladus' activity appear to provide sufficient supply for the current Titan H2O.