Northeastward motion of nighttime medium-scale traveling ionospheric disturbances at middle latitudes observed by an airglow imager

作者：Shiokawa K^*; Otsuka Y; Nishitani N; Ogawa T; Tsugawa T; Maruyama T; Smirnov S E; Bychkov V V; Shevtsov B M

来源：Journal of Geophysical Research, 2008, 113(A12): A12312.

DOI：10.1029/2008JA013417

Nighttime medium-scale traveling ionospheric disturbances (MSTIDs) observed in 630-nm airglow images at middle latitudes are known to have a predominantly northwest-southeast phase surface and to move southwestward in the Northern Hemisphere of Earth. However, the mechanisms of MSTID generation and their systematic southwestward motion have not been clarified. In this paper, we report the "northeastward'' motion of the MSTIDs observed at Paratunka, Far East Russia (52.97 degrees N, 158.25 degrees E), using an all-sky 630-nm airglow imager at 2000-2300 LT on 19 August 2007. The MSTIDs moved first southwestward but then back northeastward in the northern part of the images. The northeastward motion of the MSTIDs took place coincident with a F layer height decrease observed by an ionosonde at Paratunka. The F layer height decrease was also confirmed by an enhancement of the 630-nm airglow intensity, which seemed to propagate from northeast to southwest. This fact suggests that the F layer height decrease was caused by poleward wind enhancement rather than westward electric field. These observations imply that the F layer height decrease or the poleward thermospheric wind has some role in the northeastward turning of the MSTID propagation direction.

• 出版日期2008-12-30