Statistical Study of Seasonal and Solar Activity Dependence of Nighttime MSTIDs Occurrence Using the SuperDARN Hokkaido Pair of Radars

Abstract

AbstractWe conduct a statistical analysis on nighttime medium‐scale traveling ionospheric disturbances (MSTIDs) using the Super Dual Auroral Radar Network (SuperDARN) Hokkaido East (43.53°N, 143.61°E) high‐frequency (HF) radar data from 2009 to 2019 and the SuperDARN Hokkaido West (43.54°N, 143.61°E) HF radar data from 2016 to 2019. We analyze the line‐of‐sight Doppler velocity data, corresponding to the magnitude of the polarization electric field associated with nighttime MSTIDs. We find that the propagation direction of the nighttime MSTIDs is mainly southwestward and rotates clockwise with progressing local time. In addition, we identify a negative correlation between the nighttime MSTIDs amplitude and the solar F10.7 index. These tendencies can be explained by the Perkins instability, which is considered to be associated with the growth of nighttime MSTIDs. This study is the first to find the solar activity dependence of the polarization electric field fluctuations associated with the nighttime MSTIDs.