Case studies of the propagation characteristics of auroral TIDS with EISCAT CP2 data using maximum entropy cross-spectral analysis

• Published in: Annales Geophysicae
• Main Authors: Ma, S. Y., Schlegel, K., Xu, J. S.
• Format: Text
• Language: English
• Published: 2018
• Subjects: EISCAT
• Online Access: https://doi.org/10.1007/s00585-998-0161-3; https://angeo.copernicus.org/articles/16/161/1998/

In this paper case studies of propagation characteristics of two TIDs are presented which are induced by atmospheric gravity waves in the auroral F-region on a magnetic quiet day. By means of maximum entropy cross-spectral analysis of EISCAT CP2 data, apparent full wave-number vectors of the TIDs are obtained as a function of height. The analysis results show that the two events considered can be classified as moderately large-scale TID and medium-scale TID, respectively. One exhibits a dominant period of about 72 min, a mean horizontal phase speed of about 180 m/s (corresponding to a horizontal wavelength of about 780 km) directed south-eastwards and a vertical phase speed of 55 m/s for a height of about 300 km. The other example shows a dominant period of 44 min, a mean horizontal phase velocity of about 160 m/s (corresponding to a horizontal wavelength of about 420 km) directed southwestwards, and a vertical phase velocity of about 50 m/s at 250 km altitude. Key words. Ionosphere · Auroral ionosphere · Ionosphere-atmosphere interactions · Wave propagation)