Geophysical research: article

Overview of ANOMALITY measure application for estimating geomagnetic activity
A. Oshchenko1
R. Sidorov1
A. Soloviev1,2
E. Solovieva1,2
1 The Geophysical Center of the Russian Academy of Sciences
2 Schmidt Institute of Physics of the Earth, Russian Academy of Sciences
Journal: Geophysical research
Tome: 21
Number: 4
Year: 2020
Pages: 51-69
UDK: 550.385, 550.386.6
DOI: 10.21455/gr2020.4-4
Full text
Keywords: Earth magnetism, magnetic activity, indices of magnetic activity
Аnnotation: The possibilities of using the anomality measures (AM) in the problems of determining periods of increased and decreased geomagnetic activity, as well as the dependences of the AM average values on geomagnetic latitude in different phases of geomagnetic storms was investigated. The analysis was performed on five storms related to the final stage of the 24th solar cycle in the period of 2015-2018 and was based on the data from eight magnetic observatories located between 40° N and 60°N and 29° E and 158° E. In general, the AM average values are latitude-independent for every storm, as the algorithm takes into account the regional regime of magnetic variations and provides a normalized estimation. At the initial phase, there is a slight decrease in the AM average values with the increasing geomagnetic latitude due to the weakening of the equatorial ring current contribution. In the recovery phase, the AM average value, on the contrary, slightly increase with latitude due to the greater contribution of the polar ionosphere electrojets which occur at the final stage of the storm when approaching the auroral zone. The AM also enables recognition of the storm sudden commencement signal. In determination of magnetically quiet time intervals, AM has advantages over the traditional technique based on the planetary K