Fig. 10From: Improvements and validation of the IRI UP method under moderate, strong, and severe geomagnetic stormsStatistical parameters calculated at testing stations for foF2, for each storm time period. Trend of statistical parameters defined by Eqs. (27)–(30) related to foF2 for Fairford (left) and San Vito (right). The gap between storms number 2 and 5 at Fairford is due to the lack of ionosonde dataBack to article page