Imaging observations of midlatitude ionospheric disturbances during the geomagnetic storm of February 12, 2000

Citation
Y. Sahai et al., Imaging observations of midlatitude ionospheric disturbances during the geomagnetic storm of February 12, 2000, J GEO R-S P, 106(A11), 2001, pp. 24481-24492
Citations number
33
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Space Sciences
Journal title
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
ISSN journal
2169-9380 → ACNP
Volume
106
Issue
A11
Year of publication
2001
Pages
24481 - 24492
Database
ISI
SICI code
0148-0227(20011101)106:A11<24481:IOOMID>2.0.ZU;2-0
Abstract
Regular all-sky imaging observations of the F region OI 630 nm nightglow em ission are carried out at Rikubetsu (43.5 degreesN) and Shigaraki (34.8 deg reesN), Japan since 1998. In this paper, we present observations of the OI 630 nm emission images from these two sites with a cluster of other observa tions during the geomagnetic storm of February 12, 2000. The airglow observ ations were obtained between 1500 UT and 2000 UT (0000-0500 LT) on this nig ht. Images from both Rikubetsu and Shigaraki show the presence of mesoscale -enhanced airglow bands moving slowly (similar to 20-30 m s(-1)) to the sou thwest direction. The mesoscale band structures were also detected by an ex tensive network of GPS signal observations over Japan. The airglow observat ions at Shigaraki also show intense OI 630 nm emission in the south with se veral small-scale intensity depletion structures. We suggest that these sma ll-scale intensity depletion structures (scale size 30-50 km) are caused by possible nonlinear interaction between the mesoscale TIDs and enhanced reg ions of the equatorial ionospheric anomaly. The ionosonde observations from Wakkanai (45.4 degreesN) and Kokubunji (35.7 degreesN) show spread F signa tures between 1130 and 2100 UT and 1215 and 1715 UT, respectively, whereas no spread F was observed at Yamagawa (31.2 degreesN) and Okinawa (26.3 degr eesN). The phase fluctuations of GPS signal were observed at latitudes high er than 30 degreesN for 1400-1900 UT. These observations suggest enhanced s torm time ionospheric disturbances were confined in the midlatitudes.