https://iri.gsfc.nasa.gov/docs/iri_2007_asr.pdf

International Reference Ionosphere 2007: Improvements and new parameters

[1] We statistically analyze the ionospheric scale heights in the lower topside ionosphere based on the electron density (Ne) and temperature profiles observed from the incoherent scatter radar (ISR) at Arecibo (293.2E, 18.3N), Puerto Rico. In this study, a database containing the Arecibo ISR observations from 1966 to 2002 has been used in order to investigate the diurnal and seasonal variations and solar activity dependences of the vertical scale height (VSH), which is deduced from the electron concentration profiles

/pdf/an-analysis-of-the-scale-heights-in-the-lower-topside-4ok85px263.pdf

An analysis of the scale heights in the lower topside ionosphere based on the Arecibo incoherent scatter radar measurements

Evaluation of the IRI-2007 model options for the topside electron density

[1] The vertical scale height (VSH) in the topside ionosphere can be derived from electron density profiles. In this study, the electron density profiles retrieved from the COSMIC/FORMOSAT-3 (a Constellation Observing System for Meteorology, Ionosphere, and Climate mission; C/F3 for short) ionospheric radio occultation (IRO) observations have been collected to investigate the local time, seasonal, latitudinal, and longitudinal variations of the VSH. With the postprocessed C/F3 IRO electron density profiles during the interval from day of year (DOY) 194 in 2006 to DOY 60 in 2008, we conduct an analysis on the behaviors of VSH at an altitude of 400 km. There are appreciable latitudinal variations in VSH. A new finding is a significant peak around dip equator during daytime in four seasons. Away from the equatorial peak, it is obvious that the VSH generally increases at higher latitudes. The equatorial VSH undergoes a significant diurnal variation with a local noon maximum. The peak shifts to sunrise time with increasing dip latitude, and the values of daytime VSH become comparable with those at nighttime at low latitude in both hemispheres, which is somewhat different from the feature revealed from Arecibo incoherent scatter radar observations. One of the crucial findings in our results is the most outstanding feature of VSH, that is, the presence of a substantial longitudinal structure in equatorial regions. A wave-like longitudinal feature is found in equatorial VSH during the daytime in four seasons, while it becomes weaker or absent at other local time intervals and at higher latitudes. This investigation also confirms that the behaviors of VSH are not strongly consistent with those of the neutral or plasma-scale heights.

/pdf/topside-ionospheric-scale-heights-retrieved-from-19c6qh1tsn.pdf

Topside ionospheric scale heights retrieved from Constellation Observing System for Meteorology, Ionosphere, and Climate radio occultation measurements

Application of neural networks to South African GPS TEC modelling

[1] Shortcomings of the representation of the topside electron density profile in the International Reference Ionosphere (IRI) model have been noted in comparison with recently analyzed topside sounder data and also with total electron content (TEC) data. Various studies have proposed corrections of the IRI formulas or have introduced a new formalism. This paper reviews the different approaches, their implications for IRI, and their current status. An important challenge for topside modeling is the truthful representation of profiles in the equatorial anomaly (EA) region over the whole range of the EA fountain. This means that the latitudinal representation has to reproduce the merging of the double-peak signature at F region heights into a single peak at the top of the fountain. In this context, special emphasis is given to the coupling between topside and plasmaspheric models.

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2005RS003370

Lida Triskova

Papers

Improvements of the International Reference Ionosphere model for the topside electron density profile