Göttingen 2025 – wissenschaftliches Programm

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EP: Fachverband Extraterrestrische Physik

EP 3: Near-Earth Space I

EP 3.1: Hauptvortrag

Dienstag, 1. April 2025, 13:45–14:15, ZHG005

Atmospheric modelling from ground to lower thermosphere — •Claudia Stephan — Leibniz Institute of Atmospheric Physics at the University of Rostock, Kühlungsborn, Germany

The mesosphere and lower thermosphere (MLT) extend from an altitude of approximately 50 km to a few hundred kilometres. Highly dynamic physical processes in the MLT are driven by solar and magnetospheric forcing from above and by meteorological disturbances from below. The MLT layer is of increasing societal relevance as its weather directly affects the functionality of ground- and space-based communication and navigation systems. In addition, it hosts a growing number of satellites that monitor weather and climate or support critical technologies. Long-term trends in the MLT are mainly driven by increasing concentrations of anthropogenic carbon dioxide (CO2), which is responsible for large negative temperature trends of about -1.6 K/decade in the mesosphere. Atmospheric waves are associated with variability in winds, temperature and pressure on time scales of minutes to days. In particular, gravity waves are essential for coupling all atmospheric layers, from the troposphere to the thermosphere, but are difficult to treat in numerical models. Exascale computing allows global-scale simulations with horizontal grid spacings in the range of 1-10 km. In such models, resolved orography and non-orographic gravity wave sources provide a realistic wave forcing of the overlying atmosphere with explicitly simulated vertical energy and momentum transport. We extend these efforts to the MLT.

Keywords: Whole atmosphere modelling; Icosahedral Nonhydrostatic model; Mesosphere and lower thermosphere; Gravity waves