OMNI-2 hourly data of magnetic field strength (red curve is Bz in GSM coordinate system), solar wind speed V, dynamic pressure Pd, and Dst index (http://swdcwww.kugi.kyoto-u.ac.jp/dstae/index.html). The blue curve shows the result from the Burton model, where the input parameters are Bz, V, and Pd. The second panel from the bottom shows the ap index (https://www.gfz-potsdam.de/en/kp-index/), which is used as an input parameter for NRLMSIS2.0. Finally, the bottom panel shows the cross polar cap potential from the Weimer model, where the input parameters are the solar wind density, V, By, and Bz.