This global phenomenological model describes the large scale variations of ionospheric electron density with local time, latitude, and solar sunspot number. It is based on ionosonde data from 50 stations spanning the period 1957 to 1970. The model profile is obtained as the sum of three Modified Chapman functions for E-, F1-, and F2-layers. The model was improved by Chiu (1975) and served as the starting point for the FAIM model. The model is fairly simple, using less than 50 coefficients, which limits its application for equatorial and higher latitudes. It is, however, fast and easily manipulable and a good choice for first-order estimates. An extension for the polar cap ionosphere is being constructed.
Availability: (1) from NSSDC's Request Office on tape or on diskette; (2) retrievable from NSSDC's anonymous FTP site.
NSSDC ID: #MI-91A
B. K. Ching and Y. T. Chiu, A Phenomenological Model of Global Ionospheric Electron Density in the E-, F1-, and F2-Regions, J. Atmos. Terr. Phys. 35, 1615, 1973.
Y. T. Chiu, An Improved Phenomenological Model of Ionospheric Density, J. Atmos. Terr. Phys. 37, 1563, 1975.
NASA Official: Dr. Robert McGuire, Head of the Space Physics Data Facility