The diagnosis of long-term changes in observations of the middle atmosphere and interpretations is the aim of this topic. Research targets are for example the long-term changes in circulation patterns, the relation between the energy budget in the mesosphere with the tropospheric circulation, dynamically induced changes in stratospheric ozone and its feedback on the dynamics.
For the detection of trends, regression analysis is applied to data sets, such as for example IAP observations of water vapor, winds and ionospheric phase heights. For that purpose, data are pre-processed, known circulation signals are identified and the significance of results is quantified. Comparisons with circulation models served for their validation. The investigations rely on the analysis of observations, reanalyses and on simulations with models of different complexity (for example KMCM, see also Transport and Chemistry). Complex and simplified circulation and transport models allow for a quantification of contributions of long-term changes in the dynamical processes to the observed trends in different height regions, which can not be deduced from observations alone. Linear solutions of the governing mathematical equations are used to separate processes of first and second order.
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