Towards Cooperative Global Mapping of the Ionosphere: Fusion Feasibility for IGS and IRI with Global Climate VTEC Maps

Adam Froń,Bodo Reinisch,Ningbo Wang,Zishen Li,Dieter Bilitza,Paweł Flisek,Irina Zakharenkova,Kacper Kotulak,Ivan Galkin,Iurii Cherniak,Manuel Hernández-Pajares,David Roma Dollase,Alberto García-Rigo,Andrzej Krankowski

doi:10.3390/rs12213531

Abstract

Recommendations of the International Reference Ionosphere (IRI) Workshop 2017 in Taoyuan City, Taiwan and International GNSS Service (IGS) Workshop 2018 in Wuhan, China included establishment of an ionosphere mapping service that would fuse measurements from two independent sensor networks: IGS permanent GNSS receivers providing the vertical total electron content (VTEC) measurements and ionosondes of the Global Ionosphere Radio Observatory (GIRO) that compute the bottomside vertical profiles of the ionospheric plasma density. Using available GAMBIT software at GIRO, we introduced new VTEC products to its data roster: previously unavailable global average (climate) maps of VTEC and slab thickness based on climatological capabilities of IRI. Incorporation of the VTEC and τ maps into the GAMBIT Explorer environment provided data analysts with nearly 10-year history of the reference average VTEC records and opened access to the GAMBIT toolkit for evaluation and validation of the τ computations. This result is the first step towards establishing an infrastructure and the data workflow to provide GAMBIT users with the low latency and consistent quality and usability of the ionospheric weather-climate specifications. Combination of IGS-provided VTEC and GIRO-provided peak density of F2 layer NmF2 allows ground-based evaluation of the equivalent slab thickness τ, a derived property of the near-Earth plasma that characterizes the skewness of its vertical profile up to the GNSS spacecraft altitudes.

Highlights

Since 1998, the International GNSS Service (IGS) Ionosphere Working Group (IONO WG) has been continuously releasing global maps of the vertical total electron content (VTEC) in their rapid, final, and predicted schedules
Following the recommendations of the International Reference Ionosphere (IRI) Workshop 2017 in Taoyuan City, Taiwan and International GNSS Service (IGS) Workshop 2018 in Wuhan, China [17], we present results from a new global ionosphere mapping system that fuses data from two separate sensor networks: IGS permanent GNSS receivers providing VTEC measurements and Remote Sens. 2020, 12, 3531
During our works a dataset of climate VTEC maps was created, covering nearly twelve-year period since 2008 and new maps are built daily, all of them being available to users via https and Global Assimilative Model of Bottomside Ionosphere Timeline (GAMBIT) Explorer

Summary

Introduction

Since 1998, the International GNSS Service (IGS) Ionosphere Working Group (IONO WG) has been continuously releasing global maps of the vertical total electron content (VTEC) in their rapid, final, and predicted schedules. Contrasting the ICVC-released weather VTEC maps to their quiet-time counterpart (i.e., climate) is a powerful instrument in space physicist toolbox: such weather-minus-climate deviation maps allow rapid assessment of the near-space plasma dynamics as it responses to a wide variety of impacts in the Sun-Earth system, ranging from the forces acting in the outer space to the processes on the surface and even underneath the Earth’s crust Development of such global quiet-time VTEC reference maps proved to be a difficult task, given the staggering complexity and dynamics of the constituent subsystems and their couplings (see: [2,3]). The 30-day averaging would still capture the annual cycle specifics that are important for the weather-minus-climate analysis

Methods

Results

Discussion

Conclusion