Predictable and unpredictable ionospheric disturbances during St. Patrick's Day magnetic storms of 2013 and 2015 and on 8–9 March 2008

Abstract

AbstractWe present a comparative analysis of first principles Global Self‐consistent Model of the Thermosphere, Ionosphere, and Protonosphere (GSM TIP) in prediction of ionospheric disturbances during three geomagnetic storms: from moderate on 8–9 March 2008 and on 17–18 March 2013 to strong one on 17–18 March 2015, so‐called St. Patrick's Day storms. We have found that in general, the GSM TIP model gave reasonable prediction of both positive and negative ionospheric storms. Most difficulties have been found for the St. Patrick's Day storms. Namely, a strong positive storm at low latitudes above the Pacific and in the South Atlantic Anomaly region on the main and recovery phases could not be predicted by the model. The positive storm could be explained by ionization effect of energetic electron enhancements. Dynamics of negative ionospheric storms at middle latitudes was predicted by the GSM TIP model quite well though the amplitude of storms was underestimated. The latter could result from underestimation of the N2 contribution especially under unusual conditions of anomalous expansion of auroral precipitations to middle latitudes during the 2015 St. Patrick's Day storm.