VARIABILITY OF IONOSPHERIC F2 REGION DUE TO SUDDEN STRATOSPHERIC WARMING EVENT OF 2017

We analyzed the impact of minor Arctic sudden stratospheric warming (SSW) event of 2017 on the ionospheric F2 region, using Digisonde data from a low-mid latitude Indian station, Delhi (28.6°N, 77.2°E, 19.2°N geomagnetic latitude, 42.4°N dip). Our study revealed significant ionospheric changes, with electron densities exhibiting variations of more than 200% during this warming event. To further investigate, we examined the deviation in critical frequency ΔfoF2 from median values in the first six months of 2017 and found that the F2 layer critical frequency experiences maximum and minimum variations during the SSW period. Additionally, we observed periodicities of 7, 11, 14 and 30 days in characteristic F2 layer frequency during this event.