A new way of estimating the spatial and temporal components of the Vertical Total Electron Content gradient based on UPC‐IonSAT Global Ionosphere Maps

Qi Liu, Manuel Hernández‐Pajares, Heng Yang, Enric Monte‐Moreno, Alberto García‐Rigo, Haixia Lyu, Germán Olivares‐Pulido, Raül Orús‐Pérez
2022 Space Weather: The international journal of research and applications  
The fluctuations of the ionospheric electron density (i.e., ionosphere perturbations) have adverse impacts on the transionospheric radio signals including radar altimetry, radio communication systems, space-based remote sensing, and Global Navigation Satellite System (GNSS) positioning (e.g., Jakowski, Béniguel, et al., 2012; Jakowski, Borries, & Wilken, 2012; Monaldo, 1991) . For example, due to the large fluctuations of the ionospheric electron density, the GPS stations experienced an outage
more » ... t high latitude, and the Wide Area Augmentation System was disabled for few hours in the United States of America during the Halloween storm of 2003 (Doherty et al., 2004; Webb & Allen, 2004) , which also affected to the Test Bed of the European Geostationary Navigation Overlay Service (EGNOS) in northern Europe (Hernández-Pajares et al., 2005) . In addition, the EGNOS service was degraded during the ionospheric perturbation period of St. Patrick's Day storm in 2015. Consequently, it is important to identify the perturbation degree of the ionosphere to monitor the ionospheric state. To characterize the amplitude and phase fluctuations of GNSS signals, the ionosphere scintillation index S4 and σ ϕ were introduced in 1981 (Rino et al., 1981) . Based on Total Electron Content (TEC) from GNSS receivers, the Rate of Change of TEC Index (ROTI) was proposed as a measure of ionospheric irregularities (Pi et al., 1997) . A new ionospheric perturbation index, Regional Ionosphere Disturbances IndeX, was based on regional Neustrelitz TEC Model (Jakowski et al., 2006) . With data sets from the European Space Agency (ESA) Swarm constellation, the Ionospheric Bubble Index was generated as a level 2 product to provide information about Equatorial Plasma Bubbles (Park et al., 2013) . A global ionospheric disturbance index map, W-index map, use the TEC from Global Ionosphere Map (GIM) refer to the median TEC value of preceding 7 days to
doi:10.1029/2021sw002926 fatcat:kcbycmvwbjdmlgnybb4czr6pk4