Chiu Ionospheric Model 1975

Author:		Y. T. Chiu
		Lockheed Research Laboratory
		3251 Hanover St.
		Palo Alto, California  94304
		NSI-DECnet: LOCKHD::CHIU

Parameter:	Electron density

Brief Description:

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:	retrievable from NSSDC's anonymous FTP site 

NSSDC ID: #MI-91A

References:

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.