Comparison of the observed and modeled spectra using the velocity profiles V1-V4 (Fig. 11) and the same HDO fractional abundance as in the best fit. The red lines are the spectra modeled with the best-fit model using the original Rolffs physical profile. The observed and fitting spectra at 241 GHz are very similar to the those at 225 GHz; therefore, only the spectra at 225 GHz are plotted here.