17:15 〜 18:45
[PEM12-P30] 日本3地点での長期観測に基づく中間圏・熱圏夜間大気光の磁気嵐に対する応答の研究
キーワード：大気光、磁気嵐、中間圏、熱圏、電離層
In this presentation, we investigated responses of 6 types of mesospheric and thermospheric nocturnal airglow intensities (OH, O2, O(557.7nm), Na(589.3nm), O(630.0nm), O(777.4nm)) and OH and O2 rotational temperatures to geomagnetic storms based on superposed epoch analysis using long-term data obtained over Japan. We used airglow data obtained by the Airglow Temperature Photometers (ATPs) of Optical Mesosphere Thermosphere Imagers (OMTIs) at Rikubetsu (RIK) (43.5°N, 143.8°E, 2004.3.15-2023.10.31), Shigaraki (SGK) (34.8°N, 136.1°E, 2010.7.5-2023.10.31), and Sata (STA) (31.0°N, 130.7°E, 2004.1.1-2023.10.31) in Japan. First, we investigated the responses to 193 geomagnetic storms that existed during the period, but no significant responses were found. Next, we investigated the responses to 46 storms with minimum Dst values below -100 nT. As a result, we confirmed that the intensity of O2 and O(557.7nm) in the mesosphere and O(630.0nm) and O(777.4nm) in the thermosphere increased after the storms. These responses were more pronounced at higher latitudes (Rikubetsu). No noticeable variations were seen for the rotational temperatures. One possible reason for the increase of the mesospheric airglow intensity is that atomic oxygen produced by the dissociation of O2 molecules are transported from the auroral zone to lower latitudes. The response in thermospheric airglow is 1-2 days after the storm. We will discuss possible causes of these responses in the context of dynamical and chemical reaction of the upper atmosphere to geomagnetic storms.