Interactive comment on “Diagnosis of processes controlling water vapour in the tropical tropopause layer by a Lagrangian cirrus model” by C. Ren et al

Both referees have requested further details regarding our sedimentation scheme, and we have changed the text to make our description clearer. Our modelling framework is that of a single Lagrangian air parcel. Using a single box undoubtedly makes the realistic incorporation of sedimentation difficult, because of the issues identified by the referees. Other studies have used 1-D (height vs time) formulations in order to incorporate sedimentation. However, using such a 1-dimensional ‘curtain’ is also unrealistic, because of wind shear. If the modelling is to be carried out along trajectories, the choice,