Modelled line area maps (left) and residual maps (right) for the first window (July 2011) and corresponding to the following models: (first row) Step 1, in which we keep the Gaussian-latitude-dependent profiles of Cavalié et al. (2019) with no water vapour in the beacon new layers delimited by the pre-storm condensation level at 2 mbar and the new condensation level; (second row) Step 3, in which we set the water vapour abundance as a constant free parameter in the beacon to fit the observations. The best fit of July 2011 is presented here. The ‘x’ markers in the maps at RA=−5.9″, Dec=4.2″ (i.e. in the beacon) correspond to the line of sight for which the observed and modelled spectra are shown in Fig. 9. The contours in the residuals are given in units of σ. The solid contours refer to positive residuals and the dashed contours indicate negative residuals. The results for the six other dates are presented in Fig. C.1 for Step 1, and Fig. D.1 for Step 3.