Beschreibung:
The middle atmosphere is disturbed by planetary waves (PWs) especially in the northern hemispheric winter. The interaction of PWs with the mean flow causes Sudden Stratospheric Warmings (SSWs), the most impressive vertical coupling process of the middle atmosphere. While the stratospheric temperature increases of up to 80K within a few days it decreases in the mesosphere of up to 30K. In this thesis the average behavior of SSWS as well as unusually southward extended SSWs are studied using high-resolution local radar measurements, global satellite observations and assimilated model data.