Basic features of large-scale processes in the middle atmosphere during DYANA

International audienceLarge-scale processes in the stratosphere and mesosphere were investigated for the DYANA period, mainly on the basis of rocket sounding series and satellite-based maps. It was found that undisturbed circulation prevailed during the early winter period with low stratospheric temperatures near the Pole. Periodic warm pulses appeared in January in the upper stratosphere and an interrse warming was observed at these levels in early February, the downward penetration of which (below 25–30 km) was relatively confined. Wavenumber 1 predominated during the warming. In late February the cold cyclonic vortex was restored near the Pole and this persisted into March