Topside correction of IRI by global modeling of ionospheric scale height using COSMIC radio occultation data

The ionosphere scale height is one of the most significant ionospheric parameters, which contains information about the ion and electron temperatures and dynamics in upper ionosphere. In this paper, an empirical orthogonal function (EOF) analysis method is applied to process all the ionospheric radi...

Full description

Saved in:
Bibliographic Details
Published in:Journal of geophysical research. Space physics 2016-06, Vol.121 (6), p.5675-5692
Main Authors: Wu, M. J., Guo, P., Fu, N. F., Xu, T. L., Xu, X. S., Jin, H. L., Hu, X. G.
Format: Article
Language:English
Subjects:
Constellation Observing System for Meteorology, Ionosphere and Climate
COSMIC
Deviation
Diurnal variations
Dynamics
Electron density
Electron temperatures
Electrons
Empirical analysis
EOF
Geomagnetic latitude
Geomagnetism
Geophysics
Ionosphere
Ionospheric models
ionospheric scale height
Ionospherics
Mathematical models
Meteorology
Model accuracy
Orthogonal functions
Preserves
Radio occultation
Scale (ratio)
Scale height
Spatial resolution
Temporal resolution
topside model
Upper ionosphere
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The ionosphere scale height is one of the most significant ionospheric parameters, which contains information about the ion and electron temperatures and dynamics in upper ionosphere. In this paper, an empirical orthogonal function (EOF) analysis method is applied to process all the ionospheric radio occultations of GPS/COSMIC (Constellation Observing System for Meteorology, Ionosphere, and Climate) from the year 2007 to 2011 to reconstruct a global ionospheric scale height model. This monthly medium model has spatial resolution of 5° in geomagnetic latitude (−87.5° ~ 87.5°) and temporal resolution of 2 h in local time. EOF analysis preserves the characteristics of scale height quite well in the geomagnetic latitudinal, anural, seasonal, and diurnal variations. In comparison with COSMIC measurements of the year of 2012, the reconstructed model indicates a reasonable accuracy. In order to improve the topside model of International Reference Ionosphere (IRI), we attempted to adopt the scale height model in the Bent topside model by applying a scale factor q as an additional constraint. With the factor q functioning in the exponent profile of topside ionosphere, the IRI scale height should be forced equal to the precise COSMIC measurements. In this way, the IRI topside profile can be improved to get closer to the realistic density profiles. Internal quality check of this approach is carried out by comparing COSMIC realistic measurements and IRI with or without correction, respectively. In general, the initial IRI model overestimates the topside electron density to some extent, and with the correction introduced by COSMIC scale height model, the deviation of vertical total electron content (VTEC) between them is reduced. Furthermore, independent validation with Global Ionospheric Maps VTEC implies a reasonable improvement in the IRI VTEC with the topside model correction. Key Points A global model of ionospheric scale height is constructed by EOF analysis The modeled scale height is applied to improve the IRI topside estimation Both internal and independent validation illustrate the efficiency of the correction
ISSN:2169-9380
2169-9402
DOI:10.1002/2016JA022785