Three-dimensional imaging of atmospheric waves in the thermosphere using network observations over Japan

1)在本研究期间，SATA(鹿儿岛)和达尔文(澳大利亚)分别从2000年7月和2001年10月开始对气辉图像进行常规观测。这四个站与陆北道(北海道)和茂崎(SIGA)(自1998年10月以来)一起，继续拍摄气辉图像。在冲绳(1999年8月)和谷儿岛(2002年8月)进行了战役观察。自2000年10月以来，法布里-珀罗涉仪(FPI)在Shigaraki测量了中层和热层风。这些常规测量的快速图表可在http://stdb2.stelab.nagoya-u.ac.jp/omti/.2)上获得：a)重力波的气候学(发生、传播方向等)是从这些日本和澳大利亚站的气辉图像的统计研究中获得的。B)在中层顶区发现局部化(孤立)结构。我们认为这种结构是由波与波的非线性相互作用引起的。C)GR…的高度3)中尺度行进电离层扰动(MSTID)的结果：a)MSTID的气候学(发生、波长、传播方向等)来自对日本气辉图像的统计研究。B)基于卫星资料和模式计算的比较，包括来自FP I的背景风信息，我们发现MSTID不是由重力波直接引起的，而是对应于某些电离层不稳定所产生的电场结构。C)基于日本和澳大利亚的同步气辉成像观测，我们发现这种电场结构沿两个半球之间的磁力线传播。4)大尺度行进电离层扰动(LSTID)的结果：LSTID被识别为磁暴期间630 nm的气辉增强。根据模式计算和直达风测量，我们发现这种LSTID是由热层中的极地风增强(向赤道传播)引起的。我们还从观测到的极光带能量输入论证了极光带简单的风产生模式不能解释观测到的LSTID特征。5)基于在日本和澳大利亚同时进行的气辉成像观测，我们发现了两个半球之间的对称等离子体气泡结构。6)在研究期间，我们成功地在日本北部(北海道)观测了11次低纬极光。其中两个极光是在日本大陆(Shigaraki)观测到的，创下了日本极光测量的最低纬度记录。7)根据FPI和MU雷达同时测量的中层风，估计了气辉发射高度的时间变化。较少

1) Routine observation of airglow image has been started since July 2000 at Sata (Kagoshima) and since October 2001 at Darwin (Australia) during this research period. Together with Rikubetsu (Hokkaido) and Shigaraki (Siga) (since October 1998), these four stations continue taking airglow images. Campaign observations were carried out at Okinawa (August, 1999) and Tanegashima (August 2002). A Fabry-Perot interferometer (FPI) measures mesospheric and thermospheric wind since October 2000 at Shigaraki. Quick-look plots of these routine measurements are available at http://stdb2.stelab.nagoya-u.ac.jp/omti/.2) Results for gravity waves in the mesopause region : a) Climatology (occurrence, propagation directions, and so on) of gravity waves were obtained from statistical study of airglow images at these Japanese and Australian stations. b) Localized (isolated) structure was found in the mesopause region. We suggest that nonlinear wave-wave interactions caused this structure. c) Heights of gr … More avity waves and airglow emissions were determined by a triangulation technique using airglow images obtained at two nearby sites.3) Results for medium-scale traveling ionospheric disturbance (MSTID) : a) Climatology (occurrence, wavelength, propagation directions, and so on) of MSTIDs were obtained from statistical study of airglow images in Japan. b) Based on a comparison of satellite data and model calculations including background wind information from FPI, we show that the MSTIDs are not directly caused by gravity waves, but correspond to the electric field structure generated by some ionospheric instability. c) Based on simultaneous airglow imaging observations in Japan and Australia, we found that this electric field structure propagates along magnetic field line between the two hemispheres.4) Results for large-scale traveling ionospheric disturbance (LSTID) : LSTIDs were identified as 630-nm airglow enhancement during magnetic storms. We showed on the basis of model calculations and direct wind measurements that this LSTID was caused by poleward wind enhancement (propagating equatorward) in the thermosphere. We also argued from the observed auroral zone energy input that simple wind generation model in the auroral zone did not explain the observed LSTID features.5) Based on the simultaneous airglow imaging observations in Japan and Australia, we found symmetric plasma bubble structures between the two hemispheres.6) During the research period, we have succeeded observations of low-latitude aurora 11 times in the northern part of Japan (Hokkaido). Two of them were observed in the mainland of Japan (Shigaraki), making a record of lowest latitude of auroral measurement in Japan.7) From simultaneous measurement of mesospheric wind by the FPI and the MU radar, temporal variations of airglow emission height were estimated. Less