Modeling The Bottomside Ionospheric Electron Density Profile

A model describing the mid-latitude bottomside electron density profile is presented. The only geophysical input parameters required for the model are critical frequency, M-factor, planetary index (Ap), and 2800 MHz solar radio flux. An empirically-determined formula for calculating H(m)F2 is derived and used in the model. This formula is a function of the M-factor, local time, day number and magnetic activity. The results obtained by comparing predicted profiles to observed electron density profiles are presented in the form of mean percentage errors as a function of height and local time. The New Model IS COMPARED TO A MODEL CURRENTLY IN OPERATIONAL USE AND IS SHOWN TO BE A 10 TO 20 PERCENT IMPROVEMENT. (Author)

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).

A tentative model for the F region above hmax is provided to permit extrapolation of electron density profiled into this region. The model corresponds to a simple "Chapman" curve, and may be fitted to true height data (obtained in Part 1) by a simple graphical process.

Four separate articles are collected which deal with the construction of empirical models of the polar ionosphere. The particular emphasis in these articles is towards the radio propagation application of the models. Numerical models of the vertical electron density profiles on the topside and bottomside of the F-region are developed, and a model for sporadic-E is included. Special attention is devoted to features which are characteristic of the polar ionosphere-auroral effects, the trough, and magnetospheric cleft regions. The models are constructed specifically for convenience in computer programming, and in fact, all aspects of the models contained in this report are available in the form of Fortran computer programs. (Author).

The Dynamical Ionosphere: A Systems Approach to Ionospheric Irregularity examines the Earth’s ionosphere as a dynamical system with signatures of complexity. The system is robust in its overall configuration, with smooth space-time patterns of daily, seasonal and Solar Cycle variability, but shows a hierarchy of interactions among its sub-systems, yielding apparent unpredictability, space-time irregularity, and turbulence. This interplay leads to the need for constructing realistic models of the average ionosphere, incorporating the increasing knowledge and predictability of high variability components, and for addressing the difficulty of dealing with the worst cases of ionospheric disturbances, all of which are addressed in this interdisciplinary book. Borrowing tools and techniques from classical and stochastic dynamics, information theory, signal processing, fluid dynamics and turbulence science, The Dynamical Ionosphere presents the state-of-the-art in dealing with irregularity, forecasting ionospheric threats, and theoretical interpretation of various ionospheric configurations. Presents studies addressing Earth’s ionosphere as a complex dynamical system, including irregularities and radio scintillation, ionospheric turbulence, nonlinear time series analysis, space-ionosphere connection, and space-time structures Utilizes interdisciplinary tools and techniques, such as those associated with stochastic dynamics, information theory, signal processing, fluid dynamics and turbulence science Offers new data-driven models for different ionospheric variability phenomena Provides a synoptic view of the state-of-the-art and most updated theoretical interpretation, results and data analysis tools of the "worst case" behavior in ionospheric configurations