A Three Dimensional Ionospheric Model Using Observed Ionospheric Parameters

An electron density model, which permits a three-dimensional specification of the ionospheric structure, has been developed. The model generates realistic electron density profiles in the altitude range from 100 to 800 km by making use of selected ionospheric parameters that are routinely observed. The model also allows for the calculation of the electron distribution over the entire path of propagation of a radio signal by employing a synoptic mapping technique. The mapping technique enagles ionospheric parameters observed at specific locations to be extended and extrapolated to regions where data are not normally accessible. The electron densities that are computed are done in a manner that is totally consistent with the observed parameters needed to generate the profiles. (Author).

An automated objective analysis procedure was developed to represent the global distribution of selected ionospheric parameters on a daily basis. The analysis scheme enables the incorporation of observations or predictions of ionospheric parameters from random locations on the globle into a synoptic mapping technique that yields updated values of the parameters at specific grid points. In this report, the steps taken in the development of the analysis procedure and the accuracy of the results of global mapping of the F2 region critical frequency are described. (Author).

Using the method of Rush and Gibbs (1973), weighted means of observed values have been used to update the global prediction of f(o)F2, which are based on monthly median values derived from the Institute of Telecommunications Sciences model (1969). This procedure improved the predictions for magnetically quiet periods, for times near minimum of the solar cycle phase, and for the equinoctial months. Furthermore, a closer grid of ionosonde stations resulted in reducing the error in the f(o)F2 prediction. For the method of Rush and Gibbs (1973) to be operationally successful in global predictions of f(o)F2 however, a closer grid of ionosondes than is presently available is needed. (Author).

An instrument to remotely determine neutral density profiles in the lower thermosphere has been developed. The instrument observes ultraviolet airglow profiles in two bands: the 3371 A band for nitrogen and the 1356 A band for atomic oxygen to infer atmospheric density. Calculations of the intensities of these emissions have been made using the recent computations of energy dependent photoelectron fluxes and experimental determinations of the excitation cross section.

Published by the American Geophysical Union as part of the Geophysical Monograph Series, Volume 181. Filling the need for a 20-year lag in substantial consideration of the midlatitude ionosphere, this volume focuses on work that takes advantage of GPS and UV imaging from satellites over the past decade, two methods that have profoundly transformed our understanding of this stratum of the atmosphere. Its interdisciplinary content brings together researchers of the solar wind, magnetosphere, ionosphere, thermosphere, polar and equatorial ionospheres, and space weather. Modeling and assimilative imaging of the ionosphere and thermosphere show for the first time the complex and global impact of midlatitude ionospheric storms. The editors invited the leading experts in the following areas to contribute the chapters herein: Characterization of Midlatitude Storms Electric Field Coupling From the Heliosphere and Inner Magnetosphere Thermospheric Control of the Midlatitude Ionosphere Ionospheric Irregularities Experimental Methods and New Techniques These themes were chosen to create a path for understanding the midlatitude ionosphere. They continue to be largely valid and represent a coherent division of the subject matter. They will be critical for understanding space weather during the upcoming solar maximum. This book was inspired by the Chapman Conference of the same name held January 2007.