Investigation of Satellite Trace (ST) and Multi-reflected Echo (MRE) ionogram signatures and its possible correlation to nighttime spread F development from Cyprus over the solar mini-max (2009–2016)

Paul, Ashik; Haralambous, Haris; Oikonomou, Christina

doi:10.1016/j.asr.2020.12.040

Cited by 6 publications

(2 citation statements)

References 29 publications

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“…Similar midlatitude spread F statistics over eight European digisonde stations recorded in 2017, 2020, and 2021 were also highlighted recently [32]. In addition, the role of MSTIDs and additional ionogram signatures related to spread F development have been investigated [34,35]. In this study, based on the identification of significant ROTI activity (ROTI > 0.15 TECU/min) [36] over eight Digisonde stations during 2011, the temporal and zonal distribution of ionospheric irregularities over Europe was investigated.…”

Section: Introductionmentioning

confidence: 61%

Correlation of Rate of TEC Index and Spread F over European Ionosondes

Paul,

Rafi,

Haralambous

et al. 2024

Atmosphere

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One of the most popular indices for monitoring the occurrence and intensity of ionospheric L-band irregularities is the Rate of TEC Index (ROTI). Due to low TEC in the mid-latitude ionosphere, ROTI has received significantly less attention than the equatorial and polar ionosphere. On the other hand, spread F is an established ionogram irregularity signature. The present study aims to correlate ROTI and spread F activity over European Digisonde stations for a low-to-moderate solar activity year (2011). With a focus on the latitude-dependent occurrence, the analysis demonstrates that range spread F (RSF) has been identified for all notable ROTI (>0.15 TECU/min) cases which also coincide with MSTID activity over the stations, suggesting induced gravity waves or polarization electric fields as the driving mechanism for enhanced ROTI activity. The diurnal and seasonal features are also presented. Maximum irregularity occurrence was observed around the 45° N from 18:00 to 05:00 UT with the seasonal maximum occurrence in January. Over lower mid-latitude Digisonde stations (latitude < 45° N), the diurnal and seasonal occurrence was observed from 19:00 to 04:30 UT in July.

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Section: Introductionmentioning

confidence: 61%

Correlation of Rate of TEC Index and Spread F over European Ionosondes

Paul,

Rafi,

Haralambous

et al. 2024

Atmosphere

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“…Such a possibility might be linked with the sufficient growth of the wave structures in question, consistent with the model proposed by Tsunoda (2012). On the other hand, satellite traces have been observed on ESF as well as non‐ESF days but not on all ESF and non‐ESF days (e.g., Joshi et al., 2015; Narayanan et al., 2014; Paul et al., 2021; Zhu et al., 2015). Observations have also revealed that LSWS alone is not a reliable precursor of ESF/EPBs (Das et al., 2020).…”

Section: Discussion and Concluding Remarksmentioning

confidence: 99%

Onset Conditions and Features of Equatorial F Region Irregularities: New Insight From Collocated Digisonde and Radar Observations From Gadanki

et al. 2022

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In this paper, we study the onset conditions and features of equatorial F region irregularities linked with equatorial plasma bubbles (EPBs) using observations made simultaneously by using a DPS‐4D digisonde and the Gadanki Ionospheric Radar Interferometer (GIRI), both collocated at Gadanki. Importantly, we have employed specific analysis tools on DPS‐4D observations, providing range‐time displays of radio frequency and signal‐to‐noise ratio (SNR) of the reflected/backscattered echoes and the angle‐of‐arrival of the echoes, to characterize the echoes and to study the ambient and disturbed states of the ionosphere. Observations clearly show noticeably different background conditions, in terms of the height of the F layer base, electron density gradient and vertical drift, for the freshly generated and drifting EPBs. The zonal wavelengths of the pre‐sunset large‐scale wave structures (LSWS) observed using the DPS‐4D, however, are found to show a close connection with EPB spacings for freshly generated and drifting EPBs, consistent with earlier findings. The satellite traces were observed just prior to the equatorial spread F (ESF) and were found to be associated with the bottomside upwellings. Comparison of the range‐time displays of radio frequency and SNR of the DPS‐4D observations and the height‐time variations of SNR of the GIRI observations demonstrates that the relatively weak echoes in the DPS‐4D observations, which represent the ESF echoes, correlate fairly well temporally with the plume structures observed by the GIRI. The GIRI observations also reproduce the bottomside upwellings observed by the DPS‐4D. We propose that the bottomside upwellings are due to the growth of the LSWS and these bottomside upwellings are instrumental for the growth of the Rayleigh‐Taylor instability generating EPBs. Finally, the new aspects of the digisonde observations are discussed with regard to their usefulness in understanding and forecasting EPBs/ESF.

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