Probability of occurrence of planetary ionosphere storms associated with the magnetosphere disturbance storm time events

T. L. Gulyaeva,I. Stanislawska,F. Arikan

doi:10.5194/ars-12-261-2014

Abstract

Abstract. The ionospheric W index allows to distinguish state of the ionosphere and plasmasphere from quiet conditions (W = 0 or ±1) to intense storm (W = ±4) ranging the plasma density enhancements (positive phase) or plasma density depletions (negative phase) regarding the quiet ionosphere. The global W index maps are produced for a period 1999–2014 from Global Ionospheric Maps of Total Electron Content, GIM-TEC, designed by Jet Propulson Laboratory, converted from geographic frame (−87.5:2.5:87.5° in latitude, −180:5:180° in longitude) to geomagnetic frame (−85:5:85° in magnetic latitude, −180:5:180° in magnetic longitude). The probability of occurrence of planetary ionosphere storm during the magnetic disturbance storm time, Dst, event is evaluated with the superposed epoch analysis for 77 intense storms (Dst ≤ −100 nT) and 230 moderate storms (−100 < Dst ≤ −50 nT) with start time, t0, defined at Dst storm main phase onset. It is found that the intensity of negative storm, iW-, exceeds the intensity of positive storm, iW+, by 1.5–2 times. An empirical formula of iW+ and iW- in terms of peak Dst is deduced exhibiting an opposite trends of relation of intensity of ionosphere-plasmasphere storm with regard to intensity of Dst storm.

Highlights

Ionosphere affects radio systems due to its temporally and spatially varying and dispersive nature
The instantaneous global ionospheric map of total electron content, Global Ionospheric Maps of Total Electron Content (GIM-TEC), in magnetic coordinates frame is shown in Fig. 1a, and Fig. 1b presents the W index map produced from it
In this work we address relation of probability of the positive and negative ionosphere global storm characterized by the ionospheric W index with the magnetosphere storm evaluated with the disturbance storm time, Dst, index

Summary

Introduction

Ionosphere affects radio systems due to its temporally and spatially varying and dispersive nature. A recently developed ionospheric W index proved itself a versatile tool in distinguishing the ionospheric and plasmaspheric variability state, and identifying the stages and intensity of ionosphere storms (Gulyaeva and Stanislawska, 2008, 2010; Gulyaeva et al, 2011, 2013). As distinct from investigations of the local effects and regional features of the ionosphere storms, this study is focused on global evaluation of probability of the ionosphere storm development as a part of the chain of storm propagation from the Sun to the solar wind, magnetosphere, plasmasphere and ionosphere extending the studies carried out so far with different approaches (Kane, 1973; Lal, 1997; Zhao et al, 2007; Liu et al, 2010; Gillies et al, 2011; Gulyaeva and Veselovsky, 2012; Mukhtarov et al, 2013)

Data processing

Results

Conclusions