Fig. 2From: Improvements and validation of the IRI UP method under moderate, strong, and severe geomagnetic stormsExample of application of the F algorithm. foF2 and M(3000)F2 time series for the period October 24–29, 2016 (storm number 30 of Table 3) before (a, c, respectively) and after (b, d, respectively), applying the F algorithm. Red arrows indicate spikes which are then discarded by the F algorithmBack to article page