Monitoring of geomagnetic disturbances using the global survey method in real time

Abstract

A method for forecasting geomagnetic storms using the realization of the global survey method in real time is presented. The method is based on data from the worldwide network of neutron monitors NMDB. Using this method, we analyze the behavior of components of three-dimensional angular distribution of cosmic rays in the interplanetary medium, which were due to the first two spherical harmonics, over the period from 2013 to 2018. We have established that the main parameters that respond to the arrival of geoeffective disturbances of the interplanetary medium at Earth are changes in amplitudes of zonal (north-south) components of cosmic ray distribution. In order to select effective criteria for identifying predictors of geomagnetic disturbances and their possible temporal variations, we have made a retrospective analysis of the relationship between behaviors of the above components and geomagnetic disturbances occurring during the period of interest.

Real-Time Monitoring of Cosmic Ray Anisotropy Parameters and Short-Term Forecasting of Geomagnetic Disturbances

“…As shown by our studies, the main predictors in CR that actively respond to geoeffective disturbances of the interplanetary medium approaching Earth are changes in amplitudes of zonal (north-south) components of the high-frequency part of the isotropic CR intensity (C 00) and the first two moments of the angular distribution (C 10 and C 20 ) [Grigoryev et al, 2017], which are included in the nine parameters determined by the global survey method [Krymsky et al, 1981] and may take both positive and negative values with respect to the ecliptic plane. The predictors may also be changes in the value and direction of the first harmonic vector and in the sum of amplitudes of zonal components, which occur before the interplanetary disturbance arrives in Earth's orbit.…”

“…The predictors may also be changes in the value and direction of the first harmonic vector and in the sum of amplitudes of zonal components, which occur before the interplanetary disturbance arrives in Earth's orbit. We can empirically determine the critical levels above which positive values of any of the three components or their sums most likely predict an abrupt decrease in the Dst index at the beginning of a geomagnetic storm [Grigoryev et al, 2019]. Yet, a significant decrease in negative values of these components or their sums below a certain critical value may indicate the most disturbed phase of the geomagnetic storm.…”

NMDB database and global survey method

“…The creation of the NMDB network in 2007 served as an impetus for the implementation of the GSM method in real-time and in the study of the possibilities of the practical application of its results. The work carried out over the past 10 years in this direction (Grigoryev et al 2011a(Grigoryev et al , 2015(Grigoryev et al , 2017(Grigoryev et al , 2019Starodubtsev et al 2019) showed that it is possible to predict geomagnetic storms. As it turned out, the parameters of the angular distribution of CRs, identified using the GSM, actively respond to the approach of geoeffective disturbances of the interplanetary medium to the Earth.…”

“…Analysis of the results of the GSM for 2012-2018 made it possible to establish that anomalous changes in the magnitude and direction of the first harmonic vector (a 11 and b 11 ) and the amplitudes of the zonal (north-south) components (a 00 , a 10 and a 20 ) of the CR distribution can serve as predictors of geomagnetic disturbances. For the zonal components, the critical values of individual positive values or their sums were determined, the excess of which, with a probability of 75%, is a precursor of a sharp decrease of Dst-index at the beginning of the geomagnetic storm (Grigoryev et al 2019).…”

“…This database made it possible to implement the GSM in real-time, which meant the application of the method for monitoring and forecasting space weather. Subsequent studies in this direction are presented in the works by Grigoryev et al (2015Grigoryev et al ( , 2017Grigoryev et al ( , 2019. This paper presents the current state of the method and focuses on some practical issues of the implementation of the GSM based on NMDB data.…”