Evidence for interhemispheric stratosphere‐mesosphere coupling derived from noctilucent cloud properties

Abstract

We investigate the link between the cold summer mesopause region and the dynamics in the stratosphere. In particular, we use Odin observations of noctilucent cloud (NLC) properties as a proxy for the state of the summer mesosphere and ECMWF winter stratospheric temperatures as a proxy for the residual circulation in the stratosphere. Large areas of strong anticorrelation between winter stratospheric temperature and summer mesospheric NLC indicate that there is an interhemispheric connection. Time‐lagged cross correlation shows that the wave activity flux at 100 hPa leads the NLC response by several weeks. The presented findings are consistent with recent model studies where the modulation of the mesospheric gravity wave drag by the stratospheric planetary waves yields an interhemispheric stratosphere‐mesosphere coupling.