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Abstract

Our modern society heavily relies on the Global Navigation Satellite System (GNSS) applications that utilize trans-ionospheric radio waves. However, these applications can be highly affected by ionospheric scintillations. The GNSS service can be particularly disturbed during severe geomagnetic storms. In this study, we investigate ionospheric scintillations during major geomagnetic storms (minimum Dst < -100 nT). We make use of a network of 11 GNSS scintillation receivers of type Septentrio PolaRxS, which is operated by the Norwegian Mapping Authority. The network covers a wide latitudinal range, from the polar cap to auroral and subauroral regions. Thus, it can capture the scintillation effect associated with variable phenomena at high latitudes, such as polar cap patches, plasma blobs, auroral precipitation, and ionospheric trough. Most previous studies have focused on geomagnetic conditions that are less active and mostly only report significant phase scintillations of GNSS signals at high latitudes. However, extreme events such as the St. Patrick’s Day storm on 17 March 2015 provide good candidates for severe GNSS disruptions. In the present study, we report significant GNSS amplitude and phase scintillations, as well as losses of signal lock. We also quantify the signal power drop and loss of signal lock during major storms. In addition, we relate severe GNSS disruptions to specific ionospheric plasma conditions and ionospheric phenomena (e.g., auroral blobs). The present study is important for understanding extreme space weather conditions and it can provide important information for the development of future GNSS receivers.