Day-to-day variability of ionospheric characteristics in the American sector

Ezquer, Rodolfo Gerardo; Mosert, M.; Corbella, R.; Erazù, M.; Radicella, S. M.; Cabrera, Miguel A.; Zerda, L. de la

doi:10.1016/j.asr.2004.03.016

Cited by 30 publications

(30 citation statements)

References 7 publications

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“…The peak electron density ( N m F 2 ) of the ionosphere varies from day to day with a standard deviation of typically about 20% by day and 33% by night [ Rishbeth and Mendillo , 2001]. Since the day‐to‐day variability is of great importance to the development of empirical models such as the International Reference Ionosphere [ Bilitza , 2001], extensive studies have been made to reveal the dependence of the ionosphere on local time, seasonal and solar activity in different regions [e.g., Forbes et al , 2000; Kouris and Fotiadis , 2002; Ezquer et al , 2004; Zhang et al , 2004; Dabas et al , 2006]. As discussed by Forbes et al [2000] and Fuller‐Rowell et al [2000], the day‐to‐day variability, which is greater in the region of the equatorial ionization anomaly (EIA) area and at high latitudes, is attributed to “solar,” “geomagnetic,” and “other” causes.…”

Section: Introductionmentioning

confidence: 99%

Anomalous enhancement of ionospheric electron content in the Asian‐Australian region during a geomagnetically quiet day

et al. 2008

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[1] We investigate an event of anomalous enhancement in ionospheric electron content on 28 June 2002 from a network of 70 GPS receivers and a chain of ionosondes distributed around the Asian-Australian sector. After local sunset, the low-latitude peak electron density of the F 2 layer (N m F 2 ) was observed to increase by 200% compared to the 27-day median value. Geomagnetic environment was quiet during 27-28 June as the SYM-H index was larger than À20 nT and AE was less than 200 nT under conditions of a constant northward interplanetary magnetic field Bz. A continuously enhanced eastward electric field has been identified as the main cause of this effect, though it is not fully consistent with the prediction of Scherliess and Fejer (1997) for wind disturbance dynamo model. Our observations show that the ionosphere was very disturbed in the Northern Hemisphere during summer even under low geomagnetic activity. The large ionospheric disturbance may be caused by the combination of the effects due to auroral activity and tides, a combination that still needs further investigation. This work suggests that studying very large day-to-day variability under quiet geomagnetic conditions could reveal more about the coupling processes between the ionosphere and lower atmosphere.

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Section: Introductionmentioning

confidence: 99%

Anomalous enhancement of ionospheric electron content in the Asian‐Australian region during a geomagnetically quiet day

et al. 2008

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“…Many research works have been conducted on that matter, one to obtain knowledge of the variability of ionospheric characteristics (e.g., Ezquer et al, 2004;Rishbeth and Mendillo, 2001;Forbes et al, 2000) and others to model the ionospheric variability (e.g., Araujo-Pradere et al, 2005Mendillo et al, 2002). The ionospheric variability quantified at the midlatitude F region electron density peak reveals the following main pattern: it is larger by night, about 33%, than by day, about 20% (Rishbeth and Mendillo, 2001); it increases from typical values of 10-15% in summer to maximum values of 15-40% in winter (Araujo-Pradere et al, 2005); and the variability tends to increase with geomagnetic activity in winter and equinox but remained fairly constant in summer (Araujo-Pradere et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

Time/altitude electron density variability above Ebro, Spain

Altadill

2007

Advances in Space Research

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“…For many applications, the users of ionospheric models need to know not only the monthly average condition but also the expected deviation from the mean, or median, values. Many authors have studied the variability of ionospheric parameters using different indexes (Aravindan and Iyer, 1990;Jayachandran et al, 1995;Mosert and Radicella, 1995;Bradley, 2000;Gulyaeva and Mahajan, 2001;Radicella and Adeniyi, 2001;Rishbeth and Mendillo, 2001;Ezquer et al, 2002Ezquer et al, , 2004Kouris and Fotiadis, 2002;Mosert et al, 2002;Ezquer and Mosert, 2007;among others).…”

Section: Day-to-day Variability Of H Mmentioning

confidence: 99%

“…Taking into account that the distribution of ionospheric magnitudes is not a normal distribution and that the median and quartiles have the advantage of being less affected by large deviations which can occur during magnetic storms, we use, in this paper, the variability index proposed by Ezquer et al (2004) and Ezquer and Mosert (2007): C up -C lo where C up = upper quartile/median and C lo = lower quartile/median. Figure 7 illustrates the variations of the daily hourly values of H m together with the corresponding monthly medians at El Arenosillo for the representative months of the four seasons-winter (January), spring (April), summer (July) and fall (October)-for the HSA year 2000 (a, b, c, d) and the LSA year 2007 (e, f, g, h).…”

Section: Day-to-day Variability Of H Mmentioning

confidence: 99%

An analysis of the scale height at the F 2-layer peak over three middle-latitude stations in the European sector

et al. 2012

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This paper presents the results of an analysis of the variations of the scale height at the F 2 -layer peak (H m ) under different seasonal and solar-activity conditions. The database includes hourly H m values derived from ionograms recorded at three middle-latitude stations in the European sector: El Arenosillo (37.1• N; 353.3 • E), Ebro (40.8 • N, 0.5 • E) and Pruhonice (50.0The results show that, in general: (1) H m exhibits diurnal variation with higher values during daytime than during night-time and secondary peaks around sunrise and sunset; (2) during winter time the scale height is lower than in summer time; (3) the scale heights increase with increasing solar activity; (4) H m decreases when the latitude increases; (5) H m shows a low correlation with the F 2 -region peak parameters N m F 2 and h m F 2 and a high correlation with the thickness parameter B 0 and the equivalent slab thickness E ST ; (6) the day-to-day variability is greater at low solar activity than at high solar activity-it reaches maximum values around sunrise or sunset and it is lower around midnight than around noon at low solar activity. The results of this study are similar to those reported by other authors and can be useful for estimating the topside ionosphere from bottomside measurements and modelling.

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Day-to-day variability of ionospheric characteristics in the American sector

Cited by 30 publications

References 7 publications

Anomalous enhancement of ionospheric electron content in the Asian‐Australian region during a geomagnetically quiet day

Anomalous enhancement of ionospheric electron content in the Asian‐Australian region during a geomagnetically quiet day

Time/altitude electron density variability above Ebro, Spain

An analysis of the scale height at the F 2-layer peak over three middle-latitude stations in the European sector

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