Occurrence of sporadic-E layer over the ionospheric station of Rome: Analysis of data for thirty-two years

Pietrella, M.; Bianchi, C.

doi:10.1016/j.asr.2009.03.006

Cited by 44 publications

(34 citation statements)

References 26 publications

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“…Baggaley (1984) while analysing data covering three solar cycles, that were recorded at two stations located in the southern hemisphere, found a positive correlation between the long-term occurrences of the blanketing frequency of Es layer (fbEs) and the Zurich sunspot number R z , but he did not find any correlation for foEs. More recently, also Pietrella & Bianchi (2009), analysing data recorded at one mid-latitude station over three solar cycles, found no significant dependence of foEs occurrences on solar cycle variability. Pietrella et al (2014), by using the same data set of Pietrella & Bianchi (2009), showed also that, regardless of the solar activity, Es develops concurrently over extended regions in space, instead of being a spatially limited layer.…”

Section: Introductionmentioning

confidence: 99%

“…More recently, also Pietrella & Bianchi (2009), analysing data recorded at one mid-latitude station over three solar cycles, found no significant dependence of foEs occurrences on solar cycle variability. Pietrella et al (2014), by using the same data set of Pietrella & Bianchi (2009), showed also that, regardless of the solar activity, Es develops concurrently over extended regions in space, instead of being a spatially limited layer. Instead of considering the Es occurrence, Bossolasco & Elena (1963) and Maksyutin et al (2001) investigated this issue by analysing simply the foEs values.…”

Section: Introductionmentioning

confidence: 99%

“…The majority of works debated this issue in terms of Es occurrence percentages, with limiting varying values of the critical frequency of the Es ordinary mode of propagation (foEs) (Kotadia 1969;Baggaley 1984;Pietrella & Bianchi 2009). Kotadia (1969), who considered less than half a solar cycle data, found a negative correlation between the Es occurrence and the solar activity.…”

Section: Introductionmentioning

confidence: 99%

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On the influence of solar activity on the mid-latitude sporadic E layer

Pezzopane

Pignalberi

Pietrella

2015

J. Space Weather Space Clim.

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To investigate the influence of solar cycle variability on the sporadic E layer (Es), hourly measurements of the critical frequency of the Es ordinary mode of propagation, foEs, and of the blanketing frequency of the Es layer, fbEs, recorded from January 1976 to December 2009 at the Rome (Italy) ionospheric station (41.8°N, 12.5°E), were examined. The results are: (1) a high positive correlation between the F10.7 solar index and foEs as well as between F10.7 and fbEs, both for the whole data set and for each solar cycle separately, the correlation between F10.7 and fbEs being much higher than the one between F10.7 and foEs; (2) a decreasing long-term trend of the F10.7, foEs and fbEs time series, with foEs decreasing more rapidly than F10.7 and fbEs; (3) clear and statistically significant peaks at 11 years in the foEs and fbEs time series, inferred from Lomb-Scargle periodograms.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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On the influence of solar activity on the mid-latitude sporadic E layer

Pezzopane

Pignalberi

Pietrella

2015

J. Space Weather Space Clim.

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“…They also find that the correlation between F10.7 and fbEs is much higher than the correlation between F10.7 and foEs. Pietrella and his associates also studied the solar cycle effect on foEs over a mid-latitude station for three solar cycles and they don't find any significant dependence of solar cycle on occurrence of foEs [29]. Gwal et al studied the occurrence of GPS amplitude fluctuations during January to December 2008 and they concluded that the amplitude scintillation is solar activity dependent [30].…”

Section: Introductionmentioning

confidence: 99%

“…Prasad and co-workers studied the diurnal, seasonal and day to-day variation of h'Es and foEs for three latitudes and observed that the sporadic E layer is absent in the early morning and post sunset hours [25]. The influence of solar and geomagnetic activity on mid and low latitude Es critical frequency foEs were investigated by many researchers [26][27][28][29]. Abe et al studied the variability of foE in the equatorial ionosphere with solar activity at Ouagadougou (12.4 N, 1.5 W) [26].…”

Section: Introductionmentioning

confidence: 99%

Mid Latitude Sporadic E-layer Variability during Ascending Phase of Solar Cycle 24

et al. 2017

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The paper presents a comparative study of the ionospheric sporadic E layer parameters (fbEs, foEs, and h'Es) retrieved from ground based ionosonde at mid latitude station Yamagawa, Japan (31.20 N, 130.370 E) during the ascending phase of 24th solar cycle i.e. during January 2012 to December 2014. The comparison between the E-region parameters has been carried out on a diurnal, seasonal, annual and day night basis. The diurnal maxima of foEs, fbEs, and h'Es are generally higher during high solar activity. From the present study it is found that the highest values of fbEs are observed during the summer while the lowest values are observed during autumn at mid latitude. Similarly, the highest values of foEs are observed during the summer season while the lowest values are recorded in autumn season. However, the highest values of h'Es are recorded during the spring and the lowest values are recorded in autumn. The variability of Es during the day and night time is also studied. The sporadic E can form and disappear in a short time during either the day or night. We have also studied the percentage occurrence of sporadic E. The occurrence of Es changes from year to year.

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Autonomous identification and classification of ionospheric sporadicEin digital ionograms

Ghosh

Berkey

2015

Earth and Space Science

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This paper introduces a methodology to autonomously identify and classify ionospheric sporadic E layers (E s ) from digital ionograms acquired using a NOAA dynasonde operated at the Bear Lake Observatory (BLO) in northern Utah. This approach uses a windowed-fuzzy clustering technique to group ionospheric echoes present in digital ionograms, employing the transitive property of equivalence. The algorithm introduces a variance constraint to automatically determine the number and size of the clusters present in the data set. Principal component analysis (PCA) of the cluster shapes is employed for curvature estimation and to enable classification of the data into the four principal types of temperate latitude sporadic E. A visual evaluation of the autonomously classified ionograms suggests that the algorithm accurately identifies ∼95% of the sporadic E echoes present in the BLO data set. The paper also includes a "proof-of-concept" analysis of the methodology, deriving E s parameters for summer and winter intervals, that explicitly characterizes the diurnal and seasonal variations present in the E region at 42 ∘ N. This analysis was derived from approximately 34,000 digital ionograms acquired over 4 months. While the experimental data show lower peak E region heights than predicted by modeling studies, they are generally consistent with GPS satellite occultation measurements. Our analysis of the temporal variation of f o E during summer and winter intervals is inconsistent with previous results that suggest a seasonal E region density anomaly. The results confirm, however, the ionospheric effect of increased NO densities in both the summer and winter E region, as predicted by modeling studies. The identification of sporadic E using the approach outlined in this work markedly facilitates the analysis of E s parameters, as well as eliminating any human biases from the ionogram analysis process.

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Occurrence of sporadic-E layer over the ionospheric station of Rome: Analysis of data for thirty-two years

Cited by 44 publications

References 26 publications

On the influence of solar activity on the mid-latitude sporadic E layer

On the influence of solar activity on the mid-latitude sporadic E layer

Mid Latitude Sporadic E-layer Variability during Ascending Phase of Solar Cycle 24

Autonomous identification and classification of ionospheric sporadicEin digital ionograms

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