Evidence of Mid- and Low-Latitude Nighttime Ionospheric $E$ –$F$ Coupling: Coordinated Observations of Sporadic $E$ Layers, $F$ -Region Field-Aligned Irregularities, and Medium-Scale Traveling Ionospheric Disturbances

Liu, Yi; Zhou, Chen; Tang, Qiong; Kong, Jian; Gu, Xudong; Ni, Binbin; Yao, Yibin; Zhao, Zhengyu

doi:10.1109/tgrs.2019.2914059

Cited by 17 publications

(46 citation statements)

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“…By using Wuhan VHF radar, Wuhan GNSS network, and Wuhan ionosonde, Liu Y et al (2019b) investigated mid‐ and low‐ latitude nighttime ionospheric E–F coupling. Results show that E‐ and F‐ region irregularities, nighttime MSTIDs, strong E S , and Spread F were simultaneously observed on May 25, 2016.…”

Section: Ionospheric Irregularity and Scintillationmentioning

confidence: 99%

Recent ionospheric investigations in China (2018–2019)

Liu

Wan

2020

Earth and Planetary Physics

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Key Points:Ionospheric observations have continuously accumulated with increasing GNSS receivers being installed q Studies of ionospheric climatology and space weather highlight new physical understanding q Study of ionospheric irregularities/scintillations reports interesting features q Abstract: Since the release of the 2018 National Report of China on ionospheric research ( Liu LB and Wan WX, 2018) to the Committee on Space Research (COSPAR), scientists from Mainland China have made many new fruitful investigations of various ionospheric-related issues. In this update report, we briefly introduce more than 130 recent reports ( [2018][2019]. The current report covers the following topics: ionospheric space weather, ionospheric structures and climatology, ionospheric dynamics and couplings, ionospheric irregularity and scintillation, modeling and data assimilation, and radio wave propagation in the ionosphere and sounding techniques. ΔV para (m/s) SYM-H (nT) V para (m/s) V para (m/s) ΔV para (m/s) Figure 2. (a) The SYM-H index on 13-17 July 2012. The blue line marks the storm onset (at 06:42 UT on 15 July); yellow and gray areas indicate the 24-hour storm-time and 24-hour quiet-time intervals. (b) The blue dots denote the storm-time equatorial field-aligned plasma drifts observed by C/NOFS with red curve representing median and red lines denoting upper and lower quartile values. (c) Same as panel (b), but for the 24-hour quiet time interval. (d) The difference between (b) and (c). (e-h) Same as panels (a-d), but for the case on 7-11 July 2012 where the 24-hour quiet and storm intervals start at 04:12 UT on 7 and 9 July, respectively, after Zhang R et al. (2018). Earth and Planetary Physics

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Section: Ionospheric Irregularity and Scintillationmentioning

confidence: 99%

Recent ionospheric investigations in China (2018–2019)

Liu

Wan

2020

Earth and Planetary Physics

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“…Many studies have revealed large numbers of ionospheric irregularities with a spatial scale from meters to thousands of kilometers, manifesting as sporadic E (E S ) and spread F (SF) in ionograms (Bowman, 1990; Zhou C et al, 2017), field‐aligned irregularities (FAIs), plasma bubbles in radar maps (Kelley et al, 1981; Yamamoto et al, 1991; Zhou C et al, 2018a; Liu Y et al, 2019), traveling ionospheric disturbances (TIDs) in optical images, and total electron content (TEC) perturbation maps (Ding F et al, 2011; Huang FQ et al, 2016). When radio waves transit an ionospheric irregularity, radio signals may undergo severe signal loss and phase cycle slips known as ionospheric scintillations (Basu et al, 1988), which can affect modern communication and navigation system performance.…”

Section: Introductionmentioning

confidence: 99%

“…The formation of irregularities is generally attributed to ionospheric instability mechanisms, including: wind shear theory for E S (Mathews, 1998); two‐stream instability (TSI) and gradient‐drift instability (GDI) for E region FAIs at the equator and low latitudes (Farley, 1963; Simon, 1963); atmospheric gravity waves, GDI, Kelvin‐Helmholtz instability (KHI), and E S ‐layer instability for E region FAIs at mid‐latitudes (Woodman, 1991; Larsen, 2000; Maruyama et al, 2000; Cosgrove and Tsunoda, 2002a); Rayleigh‐Taylor (R‐T) instability for plasma bubbles and equatorial SF (Dungey, 1956; Basu and Kelley, 1979; Fejer and Kelley, 1980; Abdu, 2001); and the breaking of atmospheric gravity waves and Perkins instability for SF and medium‐scale TIDs (MSTIDs) at mid‐latitudes (Perkins, 1973; Bowman, 1990, 1991; Liu Y et al, 2019). In all of the above instability mechanisms, electric fields and neutral winds play dominant roles in the generation of ionospheric irregularities.…”

Section: Introductionmentioning

confidence: 99%

“…Unlike the equatorial and polar regions, the significant dip angle and equipotentiality of magnetic field lines in the mid‐latitude regions cause an apparent electrodynamic coupling relationship between ionospheric irregularities in the E and F regions. The importance of electrodynamic coupled processes in generating ionospheric irregularities has been extensively investigated using observations and numerical simulations, suggesting that ionospheric instabilities could be easily excited by coupled processes along magnetic field lines (Bowman, 1960; Haldoupis et al, 2003; Kelley et al, 2003; Cosgrove and Tsunoda, 2004; Yokoyama et al, 2009; Zhou C et al, 2018b; Liu Y et al, 2019, 2020).…”

Section: Introductionmentioning

confidence: 99%

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Review of ionospheric irregularities and ionospheric electrodynamic coupling in the middle latitude region

Liu

Zhou

et al. 2021

Earth and Planetary Physics

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This paper briefly reviews ionospheric irregularities that occur in the E and F regions at mid‐latitudes. Sporadic E (ES) is a common ionospheric irregularity phenomenon that is first noticed in the E layer. ES mainly appears during daytime in summer hemispheres, and is formed primarily from neutral wind shear in the mesosphere and lower thermosphere (MLT) region. Field‐aligned irregularity (FAI) in the E region is also observed by Very High Frequency (VHF) radar in mid‐latitude regions. FAI frequently occurs after sunset in summer hemispheres, and spectrum features of E region FAI echoes suggest that type‐2 irregularity is dominant in the nighttime ionosphere. A close relationship between ES and E region FAI implies that ES may be a possible source of E region FAI in the nighttime ionosphere. Strong neutral wind shear, steep ES plasma density gradient, and a polarized electric field are the significant factors affecting the formation of E region FAI. At mid‐latitudes, joint observational experiments including ionosonde, VHF radar, Global Positioning System (GPS) stations, and all‐sky optical images have revealed strong connections across different scales of ionospheric irregularities in the nighttime F region, such as spread F (SF), medium‐scale traveling ionospheric disturbances (MSTID), and F region FAI. Observations suggest that different scales of ionospheric irregularities are generally attributed to the Perkins instability and subsequently excited gradient drift instability. Nighttime MSTID can further evolve into small‐scale structures through a nonlinear cascade process when a steep plasma density gradient exists at the bottom of the F region. In addition, the effect of ionospheric electrodynamic coupling processes, including ionospheric E‐F coupling and inter‐hemispheric coupling on the generation of ionospheric irregularities, becomes more prominent due to the significant dip angle and equipotentiality of magnetic field lines in the mid‐latitude ionosphere. Polarized electric fields can map to different ionospheric regions and excite plasma instabilities which form ionospheric irregularities. Nevertheless, the mapping efficiency of a polarized electric field depends on the ionospheric background and spatial scale of the field.

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“…However, the number of ionospheric clutter sources may be higher than that of antennas in real data. Particularly when the spread ionospheric clutter exists, it often contains many irregularities [16]. Then the performance of the BSS‐ABF method is degraded due to the inferior BSS performance.…”

Section: Introductionmentioning

confidence: 99%