Global Distribution of Nighttime Medium‐Scale Traveling Ionospheric Disturbances Seen by Swarm Satellites

• Published in: Geophysical research letters Vol. 44; no. 18; pp. 9176 - 9182
• Main Authors: Kil, Hyosub, Paxton, Larry J.
• Format: Journal Article
• Language: English
• Published: Washington John Wiley & Sons, Inc 28.09.2017
• Subjects: Annual distribution; Distribution; Electron density; Ionospheric disturbances; irregularities; Latitude; middle latitude ionosphere; MSTID; Night; Night-time; Nighttime; Remote sensing; Satellites; Solstices; Spaceborne remote sensing; Traveling ionospheric disturbances; Variation
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1002/2017GL074750

The activity of nighttime medium‐scale traveling ionospheric disturbance (MSTID) in middle latitudes (±25°–40° magnetic latitudes) is investigated using the measurements of the electron density by Swarm satellites. Fractional electron density fluctuation is used as a proxy for MSTIDs, and the MSTID distribution is derived from the observations in December 2013–January 2017. The MSTID activity shows a semiannual variation in most longitudes with the primary and secondary peaks during the June and December solstices, respectively. The distinguishing feature in the MSTID distribution is the high occurrence rate of MSTIDs around 150°E longitude in June–August. The longitudinal and annual distribution of MSTIDs shows a hemispheric symmetry, which we interpret as the demonstration of conjugacy in MSTIDs. Key Points MSTIDs are the major source of middle‐latitude electron density irregularities Hemispheric symmetry exists in the distribution of MSTIDs Conjugacy is a common property in MSTIDs