GPS and GLONASS observations of large‐scale traveling ionospheric disturbances during the 2015 St. Patrick's Day storm

Abstract

AbstractUsing a comprehensive database of ~5300 ground‐based Global Navigation Satellite Systems (GNSS) stations we have investigated large‐scale traveling ionospheric disturbances (LSTIDs) during 17–18 March 2015 (St. Patrick's Day storm). For the first time, the high‐resolution, two‐dimensional maps of the total electron content perturbation were made using not only GPS but also GLONASS measurements. Several LSTIDs originated from the auroral regions in the Northern and Southern Hemispheres were observed simultaneously over Europe, North America, and South America. This storm is considered as a two‐step main phase storm. During the first main phase LSTIDs propagated over the whole daytime European region and over high latitudes of North America. During the second main phase we report (1) intense LSTIDs propagated equatorward in North America and Europe, (2) convergence of several LSTIDs originated from the opposite hemispheres in the interference zone over geomagnetic equator in South America, and (3) “super” LSTIDs with the wavefront length of more than 10,000 km observed simultaneously in North America and Europe. LSTIDs observed in three sectors had wavelength of ~1200–2500 km and wave periods of ~50–80 min. During the recovery phase on the background of the negative ionospheric storm developed over North America we detect signatures of the stream‐like structures elongated within the latitudinal range of 29°N–42°N across the U.S. These structures persisted through the nighttime to the early morning from 04 UT to 13 UT on 18 March 2015, and they were associated with the subauroral polarization stream‐induced nighttime ionospheric flows.