F2-Region Response to the Intense Space Weather Events in March 2013 and 2015 and ttheir Comparision with Similar Strennght Storms of July 2012 and June 2015 and the IRI-2016 Model
F2-Region Response to the Intense Space Weather Events in March 2013 and 2015 and ttheir Comparision with Similar Strennght Storms of July 2012 and June 2015 and the IRI-2016 Model
Wednesday, 13 February 2019
Fountain III/IV (Westin Pasadena)
Abstract:
The changes in critical frequency of F2-layer (foF2) for the geomagnetic storms storms of 17-18 March 2013 (Dst = -132 nT) and the super storm of 17-18 March 2015 (Dst = -222 nT) at two low latitude and three mid-latitude stations in the southern hemisphere, have been analyzed. The hourly values of foF2 measured with the ionosonde at low latitude stations, Darwin (Geomag. Lat., 21.96°S, long. 202.84°E) and Townsville (28.95°S, 220.72°E), and mid-latitude stations, Brisbane (36.73°S, 228.93ºE), Canberra (45.65°S, 226.30°E) and Hobart (54.17°S, 226.52°E), were obtained from World Data Centre, Bureau of Meteorology, Australia. For the intense storm of 17-18 March 2013 and the super storm of 17-18 March 2015 some mid-low latitude stations showed a short duration increase in foF2 but all stations showed a long duration decrease in foF2 during their recovery phase with percentage increase in foF2 (ΔfoF2%) varying from 26% at Darwin to 36.6% at Hobart for the March 2013 storm and above 40% for the March 2015 storm at all of the stations. A comparison of ionosonde given foF2 for equinoctial storms (March 2013 and 2015) and southern hemisphere winter storms (July 2012 and June 2015) has been made with the IRI-2016 model foF2 for Darwin, Brisbane, and Canberra stations. The increase/decrease in the IRI-2016 given foF2 is smaller but of the longer duration as compared to the ionosonde observed foF2 both for equinoctial and winter time storms. Moreover, the IRI-2016 model showed positive ionospheric effect in contrast to the negative ionosphere effect shown by ionosonde foF2 data during the recovery phase of July 2012. A study of large no storms using the IRI-2016 model data and their comparison with the ionosonde data is suggested to get better insight into the IRI-2016 model for any further development to improve the performance of its storm-time model.