Stratospheric H2O from the first year of Aura MLS

After a year of measurements from Aura MLS, the stratospheric H2O shows the expected dynamical and chemical features as a function of time and latitude. These features are evaluated partly by looking at the output fields from a stratospheric model, SLIMCAT. The model is routinely run at the University of Edinburgh, with the model output sampled at the specific MLS measurement locations, allowing a direct comparison of the model output with the MLS data. Here we present the main features of the H2O field for this first year of measurements, and evaluate their differences with the H2O fields output by SLIMCAT. The comparison shows that some features of the H2O distribution are well represented by the model, such as the morphology related to the general ascent or descent of the air masses and the low mixing ratios associated with the dehydration of the vortex. However, some other features are not so well captured and some discrepancies in the absolute mixing ratio values are apparent. These differences are discussed in terms of the model characteristics and limitations.