scholarly journals Observations of unusual daytime range spread F at middle latitude during the afternoon hours

Space Weather ◽  
2021 ◽  
Author(s):  
Lehui Wei ◽  
Chunhua Jiang ◽  
Ting Lan ◽  
Wenxuan Wang ◽  
Hua Shen ◽  
...  
Keyword(s):  
Middle Latitude ◽  
Spread F ◽  
Range Spread

scholarly journals Satellite traces, range spread-F occurrence, and gravity wave propagation at the southern anomaly crest

2010 ◽  
Vol 28 (5) ◽  
pp. 1133-1140 ◽  
Author(s):  
M. A. Cabrera ◽  
M. Pezzopane ◽  
E. Zuccheretti ◽  
R. G. Ezquer
Keyword(s):  
Wave Propagation ◽  
Gravity Wave ◽  
Electron Density ◽  
Equatorial Anomaly ◽  
Ionospheric Station ◽  
Spread F ◽  
Range Spread

Abstract. Range spread-F (RSF) and occurrence of "satellite" traces prior to RSF onset were studied at the southern peak of the ionospheric equatorial anomaly (EA). Ionograms recorded in September 2007 at the new ionospheric station of Tucumán, Argentina (26.9° S, 294.6° E, dip latitude 15.5° S), by the Advanced Ionospheric Sounder (AIS) developed at the Istituto Nazionale di Geofisica e Vulcanologia (INGV), were considered. Satellite traces (STs) are confirmed to be a necessary precursor to the appearance of an RSF trace on the ionograms. Moreover, an analysis of isoheight contours of electron density seems to suggest a relationship between RSF occurrence and gravity wave (GW) propagation.

scholarly journals Spread-F characteristics at the southern anomaly crest in South America during the descending phase of solar cycle 24

2021 ◽  
Author(s):  
Gilda de Lourdes González
Keyword(s):  
Solar Activity ◽  
South America ◽  
Communication Systems ◽  
Temporal Distribution ◽  
Plasma Bubble ◽  
Night Time ◽  
Plasma Bubbles ◽  
Wide Range ◽  
Spread F ◽  
Range Spread

Abstract Ionospheric F-region irregularities can acutely affect navigation and communication systems. To develop predictive capabilities on their occurrence, it is key to understand their variabilities in a wide range of time scales. Previous studies at low latitudes in South America have been performed mostly for the eastern sector, and fewer efforts have been done in the Argentinian region. This work presents the analysis of the spread-F (range spread-F, frequency spread-F and strong spread-F) and plasma bubble occurrence characteristics near the southern crest of the Equatorial Ionization Anomaly (Tucumán, 26.8°S, 65.2°W; magnetic latitude 15.5°S). We used ionosonde and Global Positioning System (GPS) data from November 2014 to December 2019 for different solar and geomagnetic conditions. The data shows that spread-F and plasma bubble occurrence rates peak in summer and are minimum in equinox and winter, respectively. There is, usually, a negative correlation between each type of spread-F and solar activity, whereas the opposite happens for plasma bubbles. Geomagnetic activity suppresses the generation of spread-F in equinox and summer and enhances it in winter. Plasma bubble occurrence is higher during disturbed days than during quiet days, but under medium solar activity, summer months register more plasma bubbles in quiet conditions. Range spread-F observed in winter under low solar activity is not associated with plasma bubbles originated at the magnetic equator. These results contribute to the knowledge necessary to improve the prediction of the spatial and temporal distribution of the night-time ionospheric irregularities.

scholarly journals Equatorial range spread F echoes from coherent backscatter, and irregularity growth processes, from conjugate point digital ionograms

Radio Science ◽  
2012 ◽  
Vol 47 (6) ◽  
pp. n/a-n/a ◽  
Author(s):  
M. A. Abdu ◽  
I. S. Batista ◽  
B. W. Reinisch ◽  
J. W. MacDougall ◽  
E. A. Kherani ◽  
...  
Keyword(s):  
Conjugate Point ◽  
Growth Processes ◽  
Spread F ◽  
Range Spread ◽  
Coherent Backscatter

scholarly journals Statistical analysis of low-latitude spread F observed over Puer, China, during 2015–2016

2019 ◽  
Vol 71 (1) ◽  
Author(s):  
Ting Lan ◽  
Chunhua Jiang ◽  
Guobin Yang ◽  
Yuannong Zhang ◽  
Jing Liu ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Magnetic Activity ◽  
Ionospheric Disturbances ◽  
Low Latitude ◽  
Equatorial Ionization Anomaly ◽  
Spread F ◽  
Latitude Region ◽  
Range Spread ◽  
Activity Dependence ◽  
Maximum Occurrence

AbstractStatistical analysis of spread F (SF), recorded at Puer (PUR, 22.7° N, 101.05° E, Dip Latitude 12.9° N) during 2015–2016, was carried out to reveal its characteristics at the northern equatorial ionization anomaly. In our study, SF was categorized into four types, frequency spread F (FSF), range spread F (RSF), mix spread F (MSF) and strong range spread F (SSF). The statistical results presented that FSF and MSF were dominant over Puer. Most types of SF appeared mostly in summer months, except the maximum occurrence of SSF in equinox months. Moreover, observations of SF events also showed that the solar activity and magnetic activity dependence of SF varied with seasons. Compared with observations at other region, the present results suggest that medium-scale traveling ionospheric disturbances (MSTIDs) may play a key role in generation of SF in low-latitude region.

scholarly journals Spread-F characteristics over Tucumán near the southern anomaly crest in South America during the descending phase of solar cycle 24

2021 ◽  
Author(s):  
Gilda de Lourdes González
Keyword(s):  
Solar Activity ◽  
South America ◽  
Communication Systems ◽  
Eastern Region ◽  
Plasma Bubble ◽  
Night Time ◽  
Plasma Bubbles ◽  
Wide Range ◽  
Spread F ◽  
Range Spread

Abstract Ionospheric F-region irregularities can acutely affect navigation and communication systems. To develop predictive capabilities on their occurrence, it is key to understand their variabilities in a wide range of time scales. Previous studies at low latitudes in South America have been performed mostly in the eastern region. However, there are still few reports on the spread-F over Argentina owing to a lack of ionosonde data. This work presents the analysis of the spread-F (range spread-F and frequency spread-F) and plasma bubble occurrence characteristics near the southern crest of the Equatorial Ionization Anomaly in Argentina (Tucumán, 26.8°S, 65.2°W; magnetic latitude 15.5°S). We used ionosonde and Global Positioning System (GPS) data from November 2014 to December 2019 for different solar and geomagnetic conditions. The data show that spread-F and plasma bubble occurrence rates peak in local summer and are minimum in equinox and winter, respectively. There is a negative correlation between each type of spread-F and solar activity, whereas the opposite happens for plasma bubbles. Geomagnetic activity suppresses the generation of spread-F in equinox and summer and enhances it in winter. Plasma bubble occurrence is higher during disturbed days than during quiet days, but under medium solar activity, summer months register more plasma bubbles in quiet conditions. Range spread-F observed in winter under low solar activity is not associated with plasma bubbles originated at the magnetic equator. These results contribute to the knowledge necessary to improve the prediction of the spatial and temporal distribution of the night-time ionospheric irregularities.

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