Impact of typhoon Vongfong 2014 on the ionosphere and geomagnetic field according to SWARM satellite data: 1. Wave disturbances of ionospheric plasma

The article considers the influence of large atmospheric processes on the ionosphere by the example of tropical typhoon Vongfong 2014. We use data obtained from three SWARM satellite missions (450-500 km altitude). We discuss two possible mechanisms of transfer of atmospheric disturbances to ionospheric heights. The first mechanism is the generation of acoustic-gravity waves (AGWs); the second mechanism considers the excitation of electric fields in the atmosphere. We propose new techniques for detecting the ionospheric response to AGW, which rely on low-orbit satellite data. The first technique is based on determination of relative electron density variations in the frequency band from 15 to 150-180 s, corresponding to certain scales of AGW. The second technique estimates space-time derivatives of the electron density, measured by two nearby SWARM satellites. We present and estimate the characteristic magnitudes of ionospheric response effects, their localization and spatial-temporal characteristics for the large tropical cyclone under study.