Lomb-Scargle periodograms of solar wind plasma and IMF parameters, solar wind-magnetosphere coupling functions, auroral electrojet indices, and FAC intensities. In panels (f)–(h), T represents total, D is dayside, N is nightside, NH is the northern hemisphere, and SH is the southern hemisphere. Horizontal lines in each panel indicate 95% confidence levels of the periodograms. For the periodogram analyses, we used the highest resolution data available, i.e., 2 min for FACs and 1 min for all other parameters.