On the vertical drift of ionospheric F layer during disturbance time: Results from ionosondes

Abstract

[1] The morphology of low-latitude ionosphere is greatly affected by the zonal electric field, especially at disturbance time. In this study, historical data from two low-latitude ionosondes located at Haikou and Chongqing, China, are used to study the disturbance vertical drift properties of ionospheric F layer during the initial and main phases of 50 intense storms. The disturbance drift from an empirical model is used as an indicator to denote the E Â B disturbance magnitude. It is found that the drifts both at the base and at the peak height are increased in magnitude when the disturbance becomes stronger. For the same disturbance, ionospheric vertical drifts at the base height are comparable with those at the peak height over Haikou, but they are larger than the latter over Chongqing, both drifts being smaller than those at the magnetic equator. The drifts are larger in daytime than in nighttime, but no rule is found on their seasonal dependence. This indicates that low-latitude storm time ionospheric vertical drift of the ionospheric layer exhibits both consistent and individual properties at different locations.

Variations in Electron Content Ratio and Semi-thickness Ratio during LSA and MSA periods and some Cyclone Genesis Periods using COSMIC satellite observations

“…1. Some earlier studies have admitted that solar activity Reinisch, 2006, 2007) and geomagnetic activity (Dabas et al, 1980;Park et al, 2010;Sun et al, 2012) have obvious association with ionospheric variability. The left panel (Fig.…”

“…In Fig. 1b Reinisch, 2006, 2007;Liu et al, 2011) and geomagnetic activity (Park et al, 2010;Sun et al, 2012) presumably influence the ionospheric variability through several rigorous mechanisms.…”

“…Thereafter, at noontime though, the so-called "noon bite-out" mechanism sensitively controlled the variation of ionospheric peak parameters (NmF2, HmF2), B0 remains un-affected from this type of natural wind generated mechanism (Lee and Reinisch, 2006;Sripathi, 2012). Moreover, the vertical E Â B drift velocity variation sensitively influences the ionospheric electrodynamics over this tropical region (Liu et al, 2010;Sun et al, 2012) due to horizontal geomagnetic field lines. Without any distraction, our study yields that during noontime both B0bot and BIEC parameters play dominant role in Rtb and ECR variations respectively (depicted in Fig.…”

“…Some earlier studies (e.g., DasGupta et al, 2007;Sethi et al, 2004;Sethi and Dabas, 2006;Sripathi, 2012) have unfolded so many interesting characteristic of Indian-equatorial ionosphere. Though, the traditional ground-based measurements (e.g., Sethi and Mahajan, 2002;Sun et al, 2012) are sufficient to determine the bottom-side ionospheric behaviour, the modern space-based measurements (Aragon-Angel et al, 2009) are essential to attest the topside variability in precise manner (Reinisch and Huang, 1998). Due to the coincidence of Tropical Cyclone (TC) with geomagnetic storm the authors in Afraimovich et al (2008) could not manage to detect the disturbance due to the generation of typhoon SAOMAI.…”

The asymmetric impact of global warming on US drought types and distributions in a large ensemble of 97 hydro-climatic simulations

“…In recent years, major droughts have occurred across different regions of the world 2 , including Australia 3 , China 4 , the Amazon 5 , Sahel 6 and North America 7, 8 with huge impacts on water resource management and ecosystem productivity 9–11 . In order to mitigate the losses and manage water shortages accompanying droughts, it is necessary to investigate future evolution of droughts in a consistent and comprehensive manner.…”