Comparative study of electron density from incoherent scatter measurements at Arecibo with the IRI-95 model during solar maximum

Abstract

Abstract. Arecibo (18.4 N, 66.7 W) incoherent scatter (IS) observations of electron density N(h) are compared with the International Reference Ionosphere (IRI-95) during midday (10±14 h), for summer, winter and equinox, at solar maximum (1981). The N(h) pro®les below the F2 peak, are normalized to the peak density NmF2 of the F region and are then compared with the IRI-95 model using both the standard B0 (old option) and the Gulyaeva-B0 thickness (new option). The thickness parameter B0 is obtained from the observed electron density pro®les and compared with those obtained from the IRI-95 using both the options. Our studies indicate that during summer and equinox, in general, the values of electron densities at all the heights given by the IRI model (new option), are generally larger than those obtained from IS measurements. However, during winter, the agreement between the IRI and the observed values is reasonably good in the bottom part of the F2 layer but IRI underestimates electron density at F1 layer heights. The IRI pro®les obtained with the old option gives much better results than those generated with the new option. Compared to the observations, the IRI pro®les are found to be much thicker using Gulyaeva-B0 option than using standard B0.

A top to bottom evaluation of IRI 2007 within the polar cap

“…The CADI‐derived B0 thickness parameter, used in the following analysis, was retrieved using a least squares fit of Relation (1) to the CADI bottomside true height electron density profiles down to 0.24 NmF 2 , or to NmF 1 if an F 1 ‐layer is present, where x = ( hmF 2 − h )/ B 0 [ Sethi and Mahajan , ; Sethi and Pandey , ].…”

A statistical study of ionospheric profile parameters derived from Millstone Hill incoherent scatter radar measurements

“…For B 1, earlier IRI versions [ Bilitza , 1990] took the constant value of 3. Comparisons with observations revealed large discrepancies in the bottomside density at various stations [e.g., Zhang et al , 1996; Sethi and Pandey , 2001, and references therein], therefore there were various attempts to develop a new model for B 0 and B 1 [ Huang and Reinisch , 1997; Adeniyi and Radicella , 1998; Mahajan and Sethi , 2001; Sethi et al , 2000; Zhang et al , 2000] through a series of IRI task force activities [ Radicella , 2001]. Some of the results from these efforts have now been included in the newest IRI model, IRI‐2001.…”

A modeling study offoF2andhmF2parameters measured by the Arecibo incoherent scatter radar and comparison with IRI model predictions for solar cycles 21, 22, and 23

“…The overestimation of IRI daytime f o F 2 values found in this work is in good agreement with results of previous studies. For instance, Sethi and Pandey [2000] compared IRI and Arecibo ISR data collected during solar maximum conditions (1981) and found that the values of the electron densities at all heights predicted by IRI (IRI‐95) were larger than those measured by the Arecibo ISR during midday (10–14 LT) for Summer and Equinox periods. Similar results had been found by for solar minimum conditions (1974–1977) using the IRI‐90 model [ Pandey and Sethi , 1996].…”

“…In order to model this region, several authors have used the F 2 electron density peak ( N m F 2 ) and the F 2 region peak height ( h m F 2 ) parameters. These parameters depend on various geophysical parameters including local time, season, solar and geomagnetic activity conditions and are believed to describe the overall behavior of the F 2 layer [ Liu et al , 2006; Liu et al , 2003; Zhang and Holt , 2008; Sethi and Pandey , 2000; Moen et al , 2008; Souza et al , 2010; Zhang et al , 2009; Kawamura et al , 2002; Richards , 2001; Lei et al , 2005, and references therein]. A better understanding of the variability and modeling of N m F 2 and h m F 2 parameters is crucial for the development of ionospheric prediction capabilities, improvements in existing ionospheric models, and for radio propagation studies.…”