Evaluation of a New Global Electron Density Measurement Technique for D- and E-Region Ionosphere Using Ground-Based Observations and Models

Abstract:

The E-region electron density and hence the conductivity plays an important role in the electrodynamic process of the ionosphere. However, low ionization rates in D- and E-region ionosphere cause difficulties in the measurement of background electron density and its irregularity in these altitudes compared to F-region, and hence differences exist among different measurement techniques, as well as models. As a result, the characterization of the global D- and E-region electron density as a function of local time and longitude remains a great challenge. In this work, the dataset from a new GPS-RO electron density retrieval technique for D- and E-region ionosphere are analyzed and evaluated using ground-based measurements and models. Unlike in the conventional top-down retrieval approach, where the Abel functions at the D- and E-region tangent heights carry a substantial amount of residual errors from F-region, the new technique uses a bottom-up approach that effectively removes the F-region residuals. Hence, more accurate electron density measurements are determined. While well-established ground-based measurements are limited in number, and also they only cover inland areas, leaving no coverage of ocean area, the new GPS-RO technique provides a reliable global electron density dataset that improves our understanding of the D- and E-region ionosphere and its variability.