Impact of Lower Atmosphere and High-Latitude Forcing on Thermospheric Density
Keywords:
lower atmosphere, high-latitude forcing, thermospheric densityAbstract
During the geomagnetically disturbed period from 31 January to 3 February 2024, this research examines the combined effects of decreased atmospheric forcing and high-latitude magnetospheric inputs on thermospheric neutral density. The work investigates the impact of realistic lower-boundary conditions, specifically those derived from WACCMX-SD, on the global thermospheric response relative to climatological forcing using Swarm-C satellite observations and a number of TIEGCM-based simulations. By using real lower atmospheric disturbances, density errors are regularly reduced, particularly in the northern hemisphere In many latitude zones, reductions of up to 15% have been seen. It is important to have correct representations of the connection between the magnetosphere and ionosphere because models powered by field-aligned currents (FAC) obtained from AMPERE data perform better than those employing empirical Weimer electric fields, especially at night and at high northern latitudes. Results show that complex interactions including circulation patterns, tidal variability, composition variations, and scale height differences based on altitude are the root cause of interhemispheric asymmetries in density response. The research concludes that in order to better model and forecast space weather, it is necessary to take into account both lower atmospheric dynamics and high-latitude energy inputs, since both are crucial in capturing fluctuations in thermospheric density.
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References
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