14:15 〜 14:30
[PEM13-27] The Possible Role of Turbopause on Sporadic-E Layer Formation at Middle and Low Latitudes
★Invited Papers
キーワード：sporadic E layer, atmospheric wave, turbopause
We examine the mechanism of middle and low latitude sporadic E layer formation. Es traces at high altitude (above 110 km) rapidly move down in accordance with the descent of the wind shear node, which means the important role of the tides in the formation and descent of the Es layer. However, the lower-lying Es traces do not descend with the wind shear node, whereas preserved at the bottom of the E region (~100 km) for a long time, which cannot be explained by tidal wind shear theory. The theoretical modeling results show that metallic ions can effectively accumulate by the combined effect of the zonal and meridional winds in the mesosphere and the lower thermosphere region. Numerical simulation results also demonstrate that metallic ions can accumulate without wind shear at a lower height (90–105 km) as a consequence of the MLT winds leading to the ion drifting downward. Our results provide observational evidence to support the concept that turbopause at the bottom of E region plays an important role in the formation of Es layers.