Spectral dependence of the integrated optical depth from 0.4 to 70 mbar for a mean spectrum located at 71°S using model B* (red) and model A* (black), compared to the data from Vinatier et al. (2012) for Titan (integrated between 1.7 and 0.7 mbar) and Guerlet et al. (2015) for Saturn (integrated between 3 and 0.1 mbar) from Cassini/CIRS observations. The shaded areas show the magnitude of the error in each measurement. The upper limits are displayed as triangles.