Statistical Analysis and Interpretation of High-, Mid- and Low-Latitude Responses in Regional Electron Content to Geomagnetic Storms

Abstract

Geomagnetic storm is one of the most powerful factors affecting the state of the Earth’s ionosphere. Revealing the significance of formation mechanisms for ionospheric storms is still an unresolved problem. The purpose of the study is to obtain a statistical pattern of the response in regional electron content to geomagnetic storms on a global scale to interpret the results using the upper atmosphere model (the Global Self-consistent Model of the Thermosphere, Ionosphere, and Protonosphere), to make the detailed comparison with the thermospheric storm concept, and to compare the obtained pattern with results from previous statistical studies. The regional electron content is calculated based on the global ionospheric maps data, which allows us to cover the midlatitude and high-latitude zones of both hemispheres, as well as the equatorial zone. Most of the obtained statistical pattern agrees with the thermospheric storm concept and with the previous statistical studies: ionospheric responses at ionospheric storm main phases including their seasonal dependences for the high- and midlatitudes and some features of ionospheric responses at recovery phases. However, some of the statistical patterns are inconsistent with the thermospheric storm concept or contradicts the previous statistical studies: negative midlatitude ionospheric responses at recovery phases in the local winter, the domination of the spring response in the equatorial zone, seasonal features of the positive after-effects, the interhemispheric asymmetry of ionospheric responses, and the prestorm enhancement. We obtained that the contribution of electric field to the interpretation of the zonal and diurnal averaged storm-time regional electron content (REC) disturbances is insignificant. The positive after-storm effects at different latitudes are caused by n(O) disturbances.

Latitudinal Dependence of the Ionospheric Slab Thickness for Estimation of Ionospheric Response to Geomagnetic Storms

“…O/N 2 was measured by the Global UltraViolet Imager (GUVI) at TIMED spacecraft. The role of this ratio was emphasized in different works (for example, in References [22,45] and references therein). An interesting feature was revealed for the last geomagnetic storm of March 2012 (№5).…”

“…O/N2 was measured by the Global UltraViolet Imager (GUVI) at TIMED spacecraft. The role of this ratio was emphasized in different works (for example, in References [22,45] and references therein). Under other similar conditions, the decrease of O/N2 at F region heights results in the decrease of electron concentration [45].…”

“…There are different attempts to estimate Space Weather impacts on the ionospheric variations during storms (for examples, see References [19][20][21][22]). The ionospheric response to disturbances depends on the longitude and can differ significantly in different longitudinal sectors.…”

Relation of Extreme Ionospheric Events with Geomagnetic and Meteorological Activity

“…In this paper, we take an unconventional approach to the study of extreme ionospheric events. Instead of investigating ionospheric responses to extreme space weather events (as is usual for case studies [1][2][3][5][6][7][8][9][10][11][12] or statistical investigations [15][16][17]), we collect statistics of extreme ionospheric disturbances from datasets of two ionosondes. Similar to our study, the extreme values of TEC over Japan with frequencies of once per year, 10 years, and 100 years were investigated using 22-year GPS TEC measurements and 62-year ionosonde slab thickness observations [18].…”

Accuracy of Global Ionosphere Maps in Relation to Their Time Interval

“…For example, GNSS users require ionospheric corrections to improve their position estimates [2][3][4][5]. Moreover, space weather and geophysical studies are often based on GIM data [6][7][8].…”