Ionospheric irregularities observed during the St. Patrick’s Day 2015 severe geomagnetic storm over the southern high latitude polar cap region: a case study from Antarctic Circle

The high latitude southern polar cap ionospheric irregularities observed during the St. Patrick's Day 2015 severe geomagnetic storm is reported using Total Electron Content (TEC) data of network of International Ground Stations (IGS) GPS receivers McMurdo-MCM4(-77.83
⁰
S, 166.66
⁰
E), Casey-CAS1 (-66.28
⁰
S, 110.52
⁰
E), Davis-DAV 1 (68.58
⁰
S, 77.97
⁰
E), Mawson-MAW1 (-77.83
⁰
S, 166.66
⁰
E), East Ongle Island-SYOG Mawson-MAW1 (-67.61
⁰
S, 62.87
⁰
E) and Rothera-ROTH (-67.57
⁰
N, 68.13
⁰
E), in the Antarctic Circle. The irregularities of TEC phase fluctuation i.e. Rate of TEC (ROT) and TEC rate index (ROTI) expressed in TECU/min was estimated during the period of 16-18 March, 2015.