Statistical analysis of the mid-latitude trough position during different categories of magnetic storms and different storm intensities

Abstract

The ionospheric mid-latitude trough minimum position as a function of geomagnetic storm time is identified and investigated statistically in terms of the category and the intensity of storms. The data of ion density derived from DMSP and DEMETER satellites were used to extract the trough position. The variations of mid-latitude trough in 41 moderate magnetic storms and 88 intense magnetic storms in the 23rd solar cycle were studied. The results show that the trough moves toward the equator as Dst index decreases and toward the pole as Dst index increases. Compared with the ICME, MC and CIR storms, in sheath storms the trough shifts to lower latitude at the end of the main phase, although the average storm intensity is weak. During the storm recovery phase, the rapid recovery of the trough position can be seen at the start of the recovery phase for moderate CIR storms. We also calculated the correlation between the minimum latitude of the trough position and the storm magnitude as well as other related main phase parameters during all storms. We found that the minimum latitude of the trough position exhibits a strong correlation with the storm magnitude during magnetic storms. However, the correlation coefficients between the trough position and other related main phase parameters are very low.

Temporal and Spatial Variations of Total Electron Content Enhancements During a Geomagnetic Storm on 27 and 28 September 2017

“…Foster (1993) renamed the dusk effect “SED,” which is defined as the increase in the electron density with an increasing F region peak height and latitudinal stream‐like structure around the enhanced sunward convection region. Foster (1993) also showed that the SED phenomenon tends to appear equatorward in the midlatitude trough (e.g., Yang et al, 2015, 2016) and is caused by the equatorward expansion of the enhanced two‐cell convection associated with the development of geomagnetic storms.…”

Statistical Behavior of the Longitudinal Variations of the Evening Topside Mid‐Latitude Trough Position in both Northern and Southern Hemispheres

“…The trough has been intensely investigated for several decades since Muldrew () first identified the trough with a topside sounder. Most previous studies found that the trough position mainly depends on the geomagnetic activity level, magnetic local time (MLT), and season (Ahmed et al, ; Annakuliev et al, ; Collis & Häggström, ; Ishida et al, ; Karpachev, Afonin, & Shmilauer, ; Karpachev, Deminov, & Afonin, ; Köhnlein & Raitt, ; Lee et al, ; Le et al, ; Oksman, ; Prolss, ; Pryse et al, ; Rycroft & Burnell, ; Spiro, Heelis, & Hanson, ; Tulunay, ; Tulunay & Grebowsky, ; Voiculescu, Virtanen, & Nygrén, ; Voiculescu & Nygrén, ; Yang et al, , ; Zou et al, ). The study on the longitudinal variation of the trough is restricted by the data availability, only a few studies focus on the longitudinal variation of the trough (Afonin et al, ; Besprozvannaya et al, ; He et al, ; Horvath & Lovell, , ; Karpachev & Afonin, ; Karpachev, ; Karpachev et al, ).…”

The latitudinal structure of nighttime ionospheric TEC and its empirical orthogonal functions model over North American sector

“…Zou et al [] found that the poleward wall can move equatorward rapidly after substorm onset with the speed of about 4° of geomagnetic latitude per hour. Yang et al [] found that the trough dynamics are different for different categories of magnetic storms. Compared to other storms, sheath storms cause the greatest variations in trough position.…”