A E , D S T , and Their SuperMAG Counterparts: The Effect of Improved Spatial Resolution in Geomagnetic Indices
A E , D S T , and Their SuperMAG Counterparts: The Effect of Improved Spatial Resolution in Geomagnetic Indices
复制标题
A E 、 D S T 及其 SuperMAG 对应物：地磁指数空间分辨率提高的影响
DOI：
10.1029/2020ja027828
复制
发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Bergin A
中科院分区：
文献类型：
--
作者：
Bergin A
几十年来，地磁指数被广泛用于确定空间气象事件的参数，作为各种模型的输入和空间气象规格。极光电急流指数和扰动风暴时间指数是两个跨越多个太阳活动周的极光电急流指数，已被广泛研究。利用SuperMAG的地面磁力仪协作，现在可以制作AE和DST的改进空间覆盖模拟。SME是与AE共享方法的电喷射指数。SMR是与DST共享方法的环电流指数。随着SuperMAG网络中磁强计台站数量的增加，SME和SMR的空间分辨率也在增加。我们建立的指数和他们的新SuperMAG同行之间的统计比较发现，在地磁活动的大偏移，AE系统低估SME为以后的周期。在一个太阳活动极大期，记录到的AE和SME值的分布之间的差异可以与从一个太阳活动周期到下一个太阳活动周期的变化具有相同的数量级。我们表明，DST和SMR跟踪对方，但受到一个近似的线性位移作为一个结果的程序用于映射站的磁赤道。我们解释观察到的AEandSME之间的差异与援助的一个简单的模型，基于建设方法的电喷射指数。我们表明，在AEandSME的情况下，它是不可能简单地转换之间的两个指数。
For decades, geomagnetic indices have been used extensively to parameterize space weather events, as input to various models and as space weather specifications. The auroral electrojet (AE) index and disturbance storm time index (DST) are two such indices that span multiple solar cycles and have been widely studied. The production of improved spatial coverage analogs toAEandDSTis now possible using the SuperMAG collaboration of ground‐based magnetometers.SMEis an electrojet index that shares methodology withAE.SMRis a ring current index that shares methodology withDST. As the number of magnetometer stations in the SuperMAG network increases over time, so does the spatial resolution ofSMEandSMR. Our statistical comparison between the established indices and their new SuperMAG counterparts finds that, for large excursions in geomagnetic activity,AEsystematically underestimatesSMEfor later cycles. The difference between distributions of recordedAEandSMEvalues for a single solar maximum can be of the same order as changes in activity seen from one solar cycle to the next. We demonstrate thatDSTandSMRtrack each other but are subject to an approximate linear shift as a result of the procedure used to map stations to the magnetic equator. We explain the observed differences betweenAEandSMEwith the assistance of a simple model, based on the construction methodology of the electrojet indices. We show that in the case ofAEandSME, it is not possible to simply translate between the two indices.