Plasmasphere and topside ionosphere reconstruction using METOP satellite data during geomagnetic storms

Abstract

As part of the space weather monitoring, the response of the ionosphere and plasmasphere to geomagnetic storms is typically under continuous supervision by operational services. Fortunately, Global Navigation Satellite System (GNSS) receivers on board low Earth orbit satellites provides a unique opportunity for developing image representations that can capture the global distribution of the electron density in the plasmasphere and topside ionosphere. Among the difficulties of plasmaspheric imaging based on GNSS measurements, the development of procedures to invert the total electron content (TEC) into electron density distributions remains as a challenging task. In this study, a new tomographic reconstruction technique is presented to estimate the electron density from TEC data along the METOP (METeorological OPerational) satellites. The proposed method is evaluated during four geomagnetic storms to check the capabilities of the tomography for space weather monitoring. The investigation shows that the developed method can successfully capture and reconstruct well-known enhancement and decrease of electron density variabilities during storms. The comparison with in-situ electron densities has shown an improvement around 11% and a better description of plasma variabilities due to the storms compared to the background. Our study also reveals that the plasmasphere TEC contribution to ground-based TEC may vary 10–60% during geomagnetic storms, and the contribution tends to reduce during the storm-recovery phase.

Topside Ionosphere and Plasmasphere Modelling Using GNSS Radio Occultation and POD Data

“…Since the satellite orbit is almost polar, we have defined the rising phase related to the South to North direction with an increasing LT, while the setting phase is related to the North to South direction. As shown by Prol et al [28], the METOP orbit configuration can provide distinct VTEC distributions during the rising and setting phases; however, in the present study, similar conclusions and accuracy of Figures 15 and 16 are obtained when considering VTEC values during the setting phase of the METOP satellite.…”

“…However, in order to better stabilize the ill-conditioned solution, we have defined the relaxing parameter with a significant dependence on the background. The adopted relaxing parameter is the same used by Prol et al [28]:…”

“…This may produce discontinuities in the final reconstructions due to data gaps. In the case of voxels where no rays pass through, two Gaussian functions are used to determine the amount of influence by the nearby voxels, similarly to Prol et al [28]. The Gaussian half widths are taken as σ = 2.5°along the latitudes and longitudes (converted to local time).…”

A Tomographic Method for the Reconstruction of the Plasmasphere Based on COSMIC/ FORMOSAT-3 Data

“…In addition, a few days of the analyzed dataset were affected by geomagnetic storms. A detailed view on the capabilities of the developed method to analyze the plasmaspheric response due to the geomagnetic storms is presented by Prol et al [31]. On each day, COSMIC TEC values were used to reconstruct electron density values at the positions directly above the satellite altitude; however, it was not possible to evaluate the plasmaspheric reconstructions for all days of the year (DOYs) because the orbits of COSMIC and DSMP, in many cases, are not coincident in time and/or space.…”

A new climatological electron density model for supporting space weather services

“…Jakowski et al 2005;Berdermann et al 2014). The practicability of this approach has directly been approved by Prol et al (2021) recently. The model describes the average behavior of the three-dimensional electron density distribution around the Earth up to GNSS orbit heights as a function of the solar activity characterized by the 10.7 cm solar radio flux index F10.7 as a proxy for ionizing Extreme Ultraviolet (EUV) radiation.…”