STATIONARY ANOMALIES IN STRATOSPHERIC METEOROLOGICAL DATA SETS

Several northern hemisphere stratospheric meteorological data sets are shown to contain stationary anomalies. We consider four possible expl anations for the anomalies: 1) real stationary-wave features; 2) biase s in the analysis and assimilation methods; 3) errors in data input in to the analysis and assimilation systems; and 4) tidal signals that ar e undersampled in the daily analyses. Because the easter:ly flow in th e summer stratosphere is not consistent with stationary waves and the anomalies are present in multiple analyses. we conclude that the anoma lies are a combination of biases in the input data and tidal signals t hat are aliased to zero frequency by daily sampling. Because the anoma lies are large, they can have significant impacts on many applications of the data, including trajectories and chemical transport calculatio ns.