Developing a New Stratospheric Mean Age Time Series from Combined Satellite Nitrous Oxide Data

Climate modeling studies predict a strengthening of the Brewer Dobson Circulation, which has implications for global atmospheric composition, radiation, and climate. This predicted acceleration has not been confirmed with observations, and models also disagree about the mean stratospheric circulation and mixing strength. Previous work developed a long-record of N2O-derived mean ages from Microwave Limb Sounder (MLS) observations, but this dataset has a well-known drift of decreasing values in the lower stratosphere, likely introducing biases in mean age derivations. Here, we create an N2O-derived mean age product by applying a latitude-varying Age:N2O relationship to a new combined MLS and Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) N2O dataset which is part of the Stratospheric Water and OzOne Satellite Homogenized (SWOOSH) package. This combined N2O product corrects for the MLS drift by using the ACE-FTS long-term trends with the MLS short term variability. Additionally, we compare our results with other recent age products to determine whether the corrections are robust, which will help address implications on long-term circulation variability in future studies.