A unique structure of the ionospheric current over the Asian-Oceania region determined by the combination of the ground-based and space-borne magnetometers

The ionosphere owns a complex electric current system mainly driven by the ionospheric electric field and thermospheric wind. Changes in current can generate geomagnetic signals that can be observed both on the ground and in space. In this study, we analyzed the ionospheric current in the Asia-Oceania region by utilizing geomagnetic data collected from magnetometers of ground-based observatories and SWARM satellites at ~450 km altitude. The results present the geomagnetic variations at the two distinct altitudes, encompassing longitudinal, latitudinal, and seasonal variations. Furthermore, the Ionosphere-Electrodynamics General Circulation Model (TIE-GCM) was employed to simulate the associated geomagnetic signals. This study is the first to combine dense geomagnetic data from multiple altitudes and simulations to understand the ionospheric current in the Asia-Oceania region. The differences between the observational geomagnetic signals at different altitudes, along with the simulations, reveal a unique current structure that has not been previously discovered. The findings provide a new understanding of the intricate evolution of the current systems, which contributes to our knowledge of the electric dynamics within Earth's ionosphere.