OH layer characteristics during unusual boreal winters of 2004 and 2006

We report observations of unusual mesospheric OH airglow made by the SABER instrument on the TIMED satellite. During portions of the boreal winters of 2004 and 2006, and over much of the region poleward of 60°N, the OH layer was ∼5–8 km lower than normal and twice as bright. Using retrieved volume emission rates (VERs) in two SABER channels, we document the characteristics, spatial extent, and temporal variability of the anomalous behavior. We show that it is correlated with unusual mesospheric and upper stratospheric temperature patterns that have been reported, and other observations. The unusual layer properties are likely produced by enhanced downward transport of atomic oxygen, a circumstance consistent with the planetary wave dynamics thought to be responsible for the other changes. These observations raise the possibility of using easily observed OH airglow as a proxy for perturbed meteorological conditions.