Ionospheric Storm Scale Index Based on High Time Resolution UPC‐IonSAT Global Ionospheric Maps (IsUG)

The ionospheric storms have adverse effects on the radio communications, satellite communications and also the Global Navigation Satellite Systems (GNSS) application. A new Ionospheric storm Scale from Universitat Politècnica de Catalunya (UPC) Global Ionosphere Map (GIM), IsUG, is introduced for characterizing the ionospheric state on a global scale. The IsUG is based on the Vertical Total Electron Content (VTEC) derived from the continuously computed UPC Quarter‐of‐an‐hour time resolution Rapid GIM (UQRG), taking as reference the ones during the period 1997 to 2014. It is similar to the I‐scale index previously introduced, although it was over Japan and based on raw GNSS data. The dependence of the VTEC on season, local time and geographical location at each grid point of UQRG is removed by normalizing (i.e., by substracting the mean and dividing by the corresponding standard deviation) the percentage deviation of hourly median VTEC. After validating IsUG versus I‐scale, the IsUG distribution is presented and analyzed at global scale during a severe geomagnetic storm from 7 to 10 November 2004 as an example of the potentialities of the new index. The results suggest that the IsUG global map has a great potential for the scientific study of ionospheric storms from a global perspective and also for space weather warning considering the accuracy of the recently developed real‐time GIMs. Plain Language Summary The upper part of the atmosphere, the ionosphere, affects the Global Navigation Satellite Systems (GNSS) signals crossing it. Thanks to this effect, and to the worldwide coverage of GNSS receivers, it is possible to estimate the spatial and temporal distribution of free electrons at global scale (the so called Global Ionosphere Maps, GIMs). In this work we present a new application of the GIMs, as a simple and worldwide way of providing the scale of ionospheric storm (IsUG), in agreement with a previous definition based on raw localized GNSS data, and allowing its computation in real‐time. Key Points The new ionospheric storm scale, IsUG, is presented The IsUG is based on the high resolution and rapid UPC‐IonSAT Global Ionosphere Maps (UQRG) Statistical analysis is carried out on a global scale from 1997 to 2014 comparing well with the available raw GNSS data based I‐scale index