IRI-2001 model predictions compared with ionospheric data observed at  Brazilian low latitude stations

Bertoni, F.; Sahai, Y.; Lima, W. L. C.; Fagundes, P. R.; Pillat, V. G.; Becker‐Guedes, F.; Abalde, J. R.

doi:10.5194/angeo-24-2191-2006

Cited by 52 publications

(36 citation statements)

References 13 publications

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“…They showed that post sunset values of hpF2 observed at PAL presented an intense vertical drift during all the seasons. As it is well-known, there are a wide discrepancy between TEC measurements and the IRI model predictions at equatorial and low latitude regions [Bertoni et al, 2006]. The IRI-model is able to estimate well the GPS-TEC at high-and mid-latitudes, but overestimates or underestimates at low latitudes, which was previously reported by authors [Venkatesh et al, 2011;Kumar et al, 2015a].…”

Section: Variations Of Dtec (Difference Between Tec From Gps and Iri-supporting

confidence: 60%

Comparison of GPS-TEC measurements with IRI2012-TEC predictions in the Brazilian sector during the unusual solar minimum 2009

Abreu

Martin²,

Jesús³

et al. 2017

Annals of Geophysics

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Section: Variations Of Dtec (Difference Between Tec From Gps and Iri-supporting

confidence: 60%

Comparison of GPS-TEC measurements with IRI2012-TEC predictions in the Brazilian sector during the unusual solar minimum 2009

Abreu

Martin²,

Jesús³

et al. 2017

Annals of Geophysics

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“…In Africa, the variations of the F 2 peak parameters obtained by the ionosonde at Ouagadougou (12.4 • N, 1.5 • S, 294.6 • E), Argentina (Batista and Abdu, 2004;Bertoni et al, 2006;Lee and Reinisch, 2006;Lee et al, 2008;Ezquer et al, 2008). In Europe, Ratovsky et al (2009) compared the observed ionospheric data with the IRI model at Irkutsk (52.3 • N, 104.3 • E), Russia.…”

Section: Introductionmentioning

confidence: 99%

Thailand low and equatorial F 2-layer peak electron density and comparison with IRI-2007 model

et al. 2012

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Ionosonde measurements obtained at two Thailand ionospheric stations, namely Chumphon (10.72 • N, 99.37• E, dip 3.0• N) and Chiang Mai (18.76 • N, 98.93• E, dip 12.7• N) are used to examine the variation of the F 2 -layer peak electron density (N m F 2 ) which is derived from the F 2 -layer critical frequency, f o F 2 . Measured data from September 2004 to August 2005 (a period of low solar activity) are analyzed based on the diurnal and seasonal variation and then compared with IRI-2007 model predictions. Our results show that, in general, the diurnal and seasonal variations of the N m F 2 predicted by the IRI (URSI and CCIR options) model show a feature generally similar to the observed N m F 2 . Underestimation mostly occurs in all seasons except during the September equinox and the December solstice at Chumphon, and the September equinox and the March equinox at Chiang Mai, when they overestimate those measured. The best agreement between observation and prediction occurs during the pre-sunrise to post-sunrise hours. The best agreement of the %PD values of both the options occurs during the March equinox, while the agreement is the worst during the September equinox. The N m F 2 values predicted by the CCIR option show a smaller range of deviation than the N m F 2 values predicted by the URSI option. During post-sunset to morning hours (around 21:00-09:00 LT), the observed N m F 2 at both stations are almost identical for the periods of low solar activity. However, during daytime, the observed N m F 2 at Chumphon is lower than that at Chiang Mai. The difference between these two stations can be explained by the equatorial ionospheric anomaly (EIA). These results are important for future improvements of the IRI model for N m F 2 over Southeast Asia, especially for the areas covered by Chumphon and Chiang Mai stations.

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“…These results differ from those obtained by , who conducted a comparative study for 6 months in 2002 by using the IRI-2001 model at a low-latitude station in Hainan and found that foF2 values are in favorable agreement during the daytime and are underestimated for the nighttime. In addition, Batista and Abdu (2004) and Bertoni et al (2006) performed similar investigations of the south EIA crest and found that the IRI model overestimates the values of foF2 at approximately 06:00 LT during April (autumn) and July (winter). Meanwhile, our results also show that the CCIR mode is slightly more effective when using the observed data than the URSI mode during the daytime in the equinox and winter.…”

Section: Discussionmentioning

confidence: 81%

Variations of ionospheric profile parameters during solar maximum and comparison with IRI-2007 over Chung-Li, Taiwan

Chuo

2012

Ann. Geophys.

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Abstract. This paper studies the seasonal changes in the diurnal variation of ionospheric bottomside slab thickness (B0), based on observations during high solar activities at the equatorial ionization anomaly (EIA) area station of ChungLi (121.1 • E, 24.9 • N), Taiwan. The data examined in this investigation are derived from ionograms recorded at ChungLi in 1999, and are compared with International Reference Ionosphere (IRI-2007) model values. In our data set B0 shows largest values and biggest changes during the daytime (06:00-12:00 LT) particularly in the summer. Moreover, the diurnal variation of B0 shows an abnormal peak during the pre-sunrise period, especially in the winter. The variation in the F-peak height (hmF2) is related to a thermospheric wind traveling toward the equator, which also enhances B0 during the pre-sunrise period. The results of the comparison with the IRI model show that B0 is overestimated, in both the B0-table and the Gulyaeva option, after noon LT in the equinox (B0-table and Gulyaeva average values for the overestimation are 11 and 47 km, respectively) and summer (B0-table and Gulyaeva average values for the overestimation are 23 and 71 km, respectively) periods. Furthermore, the modeled values are underestimated at approximately 31 and 14 km for the table and Gulyaeva option during the daytime in the winter, respectively. The F2-layer maximum electron density (NmF2) data show reasonably favorable agreement with the model for a high correlation coefficient of approximately 0.97, with the major difference observed at approximately noon in the equinox and winter seasons. Regarding the hmF2 data, the model shows agreement with the observed values, and the largest discrepancy (average value is 39 km) was observed in the summer and the smallest (average value is 11 km) in the equinox season. This paper provides a comprehensive discussion on the relationship among B0, the NmF2 and the hmF2 for geomagnetic storm events.

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IRI-2001 model predictions compared with ionospheric data observed at Brazilian low latitude stations

Cited by 52 publications

References 13 publications

Comparison of GPS-TEC measurements with IRI2012-TEC predictions in the Brazilian sector during the unusual solar minimum 2009

Comparison of GPS-TEC measurements with IRI2012-TEC predictions in the Brazilian sector during the unusual solar minimum 2009

Thailand low and equatorial F 2-layer peak electron density and comparison with IRI-2007 model

Variations of ionospheric profile parameters during solar maximum and comparison with IRI-2007 over Chung-Li, Taiwan

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