Ionospheric TEC disturbances induced by the 2016 NK's rocket

A rocket called as Kwangmyongsong-4 was launched from North Korea at 00:30 UT on 7 February 2016. We investigated ionospheric total electron content (TEC) depletions induced by the rocket using the Global Navigatin Satellite System (GNSS) stations in South Korea. A sudden depletion in TEC variations appeared 6 minutes after the rocket launch. The drops in slant TEC exceeded 17 TEC unit (TECU) and those in vertical TEC were approximately 7 TECU with maximum. It is remarkable that TEC drop by the 2016 Kwangmyongsong-4 rocket is larger (almost by three times) than that by the 2012 Unha-3 rocket. The horizonal velocity of the rocket was 1.6 km/s, which was estimated from horizontal distances with initial time of TEC disturbances. However, the 2012 Unha-3 rocket ( 2.5 km/s) moved faster than the 2016 Kwangmyongsong-4 rocket in the horizontal direction. Furthermore, when the rocket moved from the high latitude to low latitude, TEC disturbances reduced gradually and then the depletion was persisted a longer time at the west side (the right side of southern direction). Considering the neutral wind velocity obtained from the empirical horizontal wind model (HWM07), it suggest that TEC depletion induced by the exhaust gas of the rocket can be affected by the zonal and meridional neutral winds.