Nonmigrating tidal coupling from the MLT region into the ionosphere and upper thermosphere

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Within this project we intend to find out the coupling mechanisms that map the nonmigrating tidal signals observed in the mesosphere/lower thermosphere (MLT) region into the ionosphere and upper thermosphere, where the presence of these tides was identified in numerous quantities. A consequent next step is to identify the coupling processes behind them. For this we make use of CHAMP measurements, on the one hand, where the prominent wave-4 structure was revealed in the zonal wind, equatorial electrojet (EEJ) and electron density. On the other hand, tidal wind fields of the thermosphere derived from the Hough Mode Extention (HME) technique based on TIMED measurements and vertical plasma drifts derived from ROCSAT-1 measurements are available to conduct the research. Modeling studies performed with the TIME-GCM will be used to bridge the unsampled regions and to test the physics behind the coupling processes. They furthermore shall help explaining the observed annual variations of the tidal signals.