AI 中文总结
该研究开发了基于光球磁场的地磁活动光球指数（PIGA），通过线性回归关联威尔科克斯太阳观测台磁图与Kp指数，能较好捕捉地磁活动演化，可用于太阳地球有效性研究及太阳磁场重建。
AI 中文摘要
地磁指数用于量化地球磁场的扰动，是追踪日地效应对地球影响的重要空间天气与空间气候记录。尽管地磁活动起源于光球磁场，但二者至今未被直接关联。我们开发了地磁活动的光球指数（PIGA），该指数基于太阳综合磁图中的光球磁场来测量太阳的地球有效性。我们利用威尔科克斯太阳观测台的综合磁图，通过线性回归将光球磁场的赤道偶极分量与轴向偶极分量和地磁Kp指数关联，以此构建PIGA。PIGA以太阳自转的分辨率很好地捕捉了过去50年地磁活动的演化，与地磁Kp指数的线性相关系数为0.71。PIGA可利用全球太阳磁场的主导结构便捷地测量太阳的地球有效性，例如可用于通过历史模拟或预测的太阳磁场研究太阳的地球有效性，还可利用观测到的地磁活动作为额外约束，用于太阳磁场的早期磁场重建。
英文摘要
Geomagnetic indices quantify the disturbances of the Earth's magnetic field. They form an important space weather and space climate record that tracks solar-terrestrial effects on the Earth. Although geomagnetic activity has its origins in the photospheric magnetic fields, the two have so far not been directly related. We develop a photospheric index of geomagnetic activity (PIGA) that measures the geoeffectiveness of the Sun based on photospheric magnetic field as presented in synoptic magnetograms. We construct the PIGA from synoptic magnetograms of Wilcox Solar Observatory by relating the equatorial and axial dipole components of the photospheric magnetic field to the geomagnetic Kp index by means of linear regression. PIGA captures well the evolution of the geomagnetic activity over the past 50 years at the resolution of solar rotation, having linear correlation of 0.71 with the geomagnetic Kp index. PIGA makes it straightforward to measure the geoeffectiveness of the Sun using the dominant structure of the global solar magnetic field. PIGA can for example be used to study the geoeffectiveness of the Sun using historical simulations or the predicted solar magnetic field. PIGA also allows to use observed geomagnetic activity as an additional constraint for the early magnetic field reconstructions of the solar magnetic field.
Comments10 pages, 4 figures
