Response of Ionospheric Profile Parameters to Equatorial Electrojet Over Peruvian Station

Bello, S. A.; Abdullah, Mardina; Hamid, Nurul Shazana Abdul; Reinisch, B. W.; Yoshikawa, Akimasa; Fujimoto, Akiko

doi:10.1029/2018ea000537

Cited by 8 publications

(4 citation statements)

References 49 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…On the other hand, the Cachimbo (SAMA boundary) station located close to the magnetic equator presented f o F 2 values less than 16 MHz during the campaign. Recently, Bello et al () presented the response of the N m F 2 , h m F 2 , and B 0 ionospheric to the Equatorial Electrojet at Jicamarca, Peru (12.0° S, 76.8° W, dip angle = −0.05°), away from the SAMA. Considering the results representing solar minimum, the authors reported that N m F 2 reach peaks of 8.8 × 10 11 electrons per m 3 (~8.5 MHz) during equinoxes, 9.5 × 10 11 electrons per m 3 (~8.8 MHz) in summer, and 5.7 × 10 11 electrons per m 3 (~6.8 MHz) in winter between 15:00 UT and 17:00 UT.…”

Section: Resultsmentioning

confidence: 99%

On the Sources of the Ionospheric Variability in the South American Magnetic Anomaly During Solar Minimum

Moro

Xu²,

Denardini

et al. 2019

JGR Space Physics

View full text Add to dashboard Cite

We investigate for the first time the variability of the F2 layer critical frequency (foF2), its peak height (hmF2), the thickness parameter B0, and the E region critical frequency (foE) over Santa Maria (29.7° S, 53.7° W, dip angle = −37°), a station located in the central region of the South American Magnetic Anomaly. The selected ionospheric parameters were obtained from ionograms recorded by a recent Digisonde Portable Sounder 4‐D. The time period covers 309 days from 1 September 2017 to 30 August 2018. The diurnal analyses revealed a large day‐to‐day ionospheric variability, with some peculiarities as a strong semiannual pattern superimposed to expected ionospheric behavior. Furthermore, the results show significant differences between the averaged foF2 in December and June solstices, revealing a possible presence of the annual asymmetry. The coefficient of variation (CV) is used as a quantitative description of the variability of each parameter versus time and season. Considering low solar flux and geomagnetically quiet days only, we note that CV is smaller during the daytime and larger during nighttime for all parameters. The least variable ionospheric parameter in our study is foE, while the most variable one is B0. Regarding the F2 layer parameters, we observe that foF2 is much more variable than hmF2. We attribute the observed CV to the neutral atmosphere source over Santa Maria. The ionospheric variability is in general enhanced during geomagnetically disturbed periods. The estimated CV is higher over Santa Maria than Wuhan, China (30.5° N, 114.4° E, dip angle = 46°), a station with no influence of the South American Magnetic Anomaly.

show abstract

Section: Resultsmentioning

confidence: 99%

On the Sources of the Ionospheric Variability in the South American Magnetic Anomaly During Solar Minimum

Moro

Xu²,

Denardini

et al. 2019

JGR Space Physics

View full text Add to dashboard Cite

show abstract

“…Bello et al (2019) found significant positive correlations of EEJ and 2 m hF and of EEJ and electron density for low solar activities. This suggests the combined effect of the wind and  EB drift from E layer.…”

mentioning

confidence: 75%

“…We found that the quiet-time 2 m hF increases for ~2 hours before sunrise and peaks at postsunset during the equinoctial and summer months over Jicamarca (Bello et al, 2019). The presunrise increase is controlled by the electron density production processes by the combination of solar radiation at a high altitude near sunrise and solar zenith angle (Lee et al, 2008).…”

Section: Variability In the Height Of The Peak Of The F-layermentioning

confidence: 90%

Solar Radiation and Geomagnetic Contribution of Consecutive 27-Day Recurrent Geomagnetic Storms to Variations of Equatorial Ionospheric Parameters and Spread F

YEERAM

2024

Preprint

View full text Add to dashboard Cite

This study investigates solar radiation and geomagnetic effects of consecutive 27-day recurrent geomagnetic storms (RGSs) during 2007 on the variabilities in the equatorial ionospheric F-region in American Peruvian sector. Results show correspondence of quasi-periodic variations between geomagnetic activities and ionospheric responses in the F-region. In High-Intensity Long-Duration Continuous (AE) Activity (HILDCAA) events, the ionospheric responses are more variable than in non-HILDCAA. The critical frequency and peak heights of the F-layer tend to increase during storm-time in summer months, but decrease in response to enhanced equatorial electrojets. A new classification of daily variations in the virtual height of the F-layer (h′F) is proposed: (mode A) mixing of great height before noon and low height before midnight, (mode B) moderate height before midnight, and (mode C) mixing of low height before noon and great height before midnight. These (h′F) modes efficiently characterize ionospheric variabilities and processes. The great uplifts of (h′F) during night-time coincide with the presence of strong disturbance dynamo electric fields and disturbed neutral winds generated by intensified Joule heating in the summer months. The solar EUV plays a role in the uplifts during daytime. Zonal electric field disturbances and perturbations in neutral meridional winds critically contribute to the equatorial ionospheric responses and ESF variability. Most of inhibited/suppressed ESF occurred in mode A and in overshielding conditions. The inhibited ESF in the recovery phase is mainly contributed by a cooling state after great uplifts by daytime thermospheric winds.

show abstract

“…In the same manner, the poleward wind that lowers the ionosphere would retard the speed of the growth of TEC near the EIA crest. Near the northern EIA crest at the Peruvian sector, the northward winds only occur at December Solstice (Figure 7h) when the F region resides at lower altitudes [41]. Thus, during the development of EIA, the TEC growth of the northern crest might be retarded, resulting in a delayed onset.…”

Section: Discussionmentioning

confidence: 99%

Seasonal and Interhemispheric Effects on the Diurnal Evolution of EIA: Assessed by IGS TEC and IRI-2016 over Peruvian and Indian Sectors

et al. 2021

View full text Add to dashboard Cite

The global total electron content (TEC) map in 2013, retrieved from the International Global Navigation Satellite Systems (GNSS) Service (IGS), and the International Reference Ionosphere (IRI-2016) model are used to monitor the diurnal evolution of the equatorial ionization anomaly (EIA). The statistics are conducted during geomagnetic quiet periods in the Peruvian and Indian sectors, where the equatorial electrojet (EEJ) data and reliable TEC are available. The EEJ is used as a proxy to determine whether the EIA structure is fully developed. Most of the previous studies focused on the period in which the EIA is well developed, while the period before EIA emergence is usually neglected. To characterize dynamics accounting for the full development of EIA, we defined and statistically analyzed the onset, first emergence, and the peaks of the northern crest and southern crest based on the proposed crest-to-trough difference (CTD) profiles. These time points extracted from IGS TEC show typical annual cycles in the Indian sector which can be summarized as winter hemispheric priority, i.e., the development of EIA in the winter hemisphere is ahead of that in the summer hemisphere. However, these same time points show abnormal semiannual cycles in the Peruvian sector, that is, EIA develops earlier during two equinoxes/solstices in the northern/southern hemisphere. We suggest that the onset of EIA is a consequence of the equilibrium between sunlight ionization and ambipolar diffusion. However, the latter term is not considered in modeling the topside ionosphere in IRI-2016, which results in a poor capacity in IRI to describe the diurnal evolution of EIA. Meridional neutral wind’s modulation on the ambipolar diffusion can explain the annual cycle observed in the Indian sector, while the semiannual variation seen in the Peruvian sector might be due to additional competing effects induced by the F region height changes.

show abstract

Response of Ionospheric Profile Parameters to Equatorial Electrojet Over Peruvian Station

Cited by 8 publications

References 49 publications

On the Sources of the Ionospheric Variability in the South American Magnetic Anomaly During Solar Minimum

On the Sources of the Ionospheric Variability in the South American Magnetic Anomaly During Solar Minimum

Solar Radiation and Geomagnetic Contribution of Consecutive 27-Day Recurrent Geomagnetic Storms to Variations of Equatorial Ionospheric Parameters and Spread F

Seasonal and Interhemispheric Effects on the Diurnal Evolution of EIA: Assessed by IGS TEC and IRI-2016 over Peruvian and Indian Sectors

Contact Info

Product

Resources

About