Correlations between solar, interplanetary-medium parameters, and geomagnetic-activity proxies in 27-day averages (a Bartels rotation) were analyzed for the 2009 – 2016 time interval. In this analysis, two new proxies were considered: i) \(B_{zs}\) GSM (Geocentric Solar Magnetic), calculated as the daily percentage of the IMF southward component along the GSM \(z\)-axis and then averaged every 27 days; ii) four magnetospheric indices (T-indices), calculated from the local north–south (\(x\)) contributions of the magnetosphere’s cross-tail (TAIL), the symmetric ring current (SRC), the partial ring current (PRC), and the Birkeland current (FAC), derived from the Tsyganenko and Sitnov (J. Geophys. Res. 110, A03208, 2005: TS05) semi-empirical magnetospheric model. Our results suggest that, among the parameters tested in this study, solar facular areas, interplanetary magnetic-field intensity and new proxies derived from the TS05 model could be taken into account in an empirical model, with a 27-day resolution, to explain geomagnetic activity felt on the Earth’s surface in terms of solar-surface features and the IMF condition. We further retrieve a clear annual oscillation in series of 27-day-mean values of toward/away asymmetries of geomagnetic-activity indices, which can be interpreted in the light of the Russell–McPherron hypothesis for the semiannual variation of geomagnetic activity.

分析了 2009 年至 2016 年时间间隔的 27 天平均值（巴特尔旋转）中太阳、行星际介质参数和地磁活动代理之间的相关性。在此分析中，考虑了两个新代理：i)  \(B_{zs}\) GSM（地心太阳磁），计算为沿 GSM \(z\)轴的 IMF 南向分量的每日百分比，然后取平均值每 27 天；ii) 四个磁层指数 (T-indices)，由磁层横尾 (TAIL)、对称环电流 (SRC)、部分环电流 (PRC) 的局部南北 ( \(x\) ) 贡献计算)，以及源自 Tsyganenko 和 Sitnov ( J. Geophys. Res. 110, A03208, 2005: TS05) 半经验磁层模型。我们的结果表明，在本研究测试的参数中，太阳光斑面积、行星际磁场强度和源自 TS05 模型的新代理可以在具有 27 天分辨率的经验模型中考虑，以解释地磁根据太阳表面特征和 IMF 条件在地球表面感受到的活动。我们进一步检索了地磁活动指数走向/远离不对称性的一系列 27 天平均值的明显年度振荡，这可以根据关于地磁活动半年变化的 Russell-McPherron 假设进行解释。