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Abstract All‐sky imagers located in Asiago, Italy (45.87oN, 11.53oE; 40.7omagnetic latitude) and Sutherland, South Africa (32.37oS, 20.81oE; −40.7omagnetic latitude) are used to study magnetically conjugate medium scale traveling ionospheric disturbances (MSTIDs). We present initial results from the first year of joint Asiago‐Sutherland data sets from July 2016 to June 2017. The 630.0‐nm airglow perturbations showing different kinds of waves were frequently observed. Some of these wave events resemble MSTIDs propagating south‐westward in Asiago, typical direction observed at other longitude sectors in the northern hemisphere. They are mostly observed as single bands propagating through the field of view of the all‐sky imagers. We select and analyze five cases of magnetically conjugate bands associated with MSTIDs. The bands observed at Sutherland move mainly westward, noticeably different from the north‐west direction of propagation of MSTIDs observed in the southern hemisphere. We compare the MSTIDs propagation speeds and find that three cases show larger values at Sutherland. When we compare the zonal speeds all the cases show larger values at Sutherland. On average, the propagation speed at Sutherland is 20% larger and the zonal speed is ~35% larger. The westward motion at Sutherland is explained by taking onto account how its magnetic declination (~24oW) affects the orientation of the bands. The larger speed at Sutherland is due to the weaker Earth's magnetic field in the southern hemisphere and the particular configuration of the magnetic field lines in this longitude sector.
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All‐Sky Imaging Observations and Modeling of Bright 630‐nm Airglow Structures Associated With MSTIDs
Abstract An all‐sky imager at El Leoncito Observatory (−31.8°, 69.3°W, 18.2° magnetic latitude) is used to study 630.0‐nm airglow emissions related to medium‐scale traveling ionospheric disturbances (MSTIDs). On the night of 6 December 2007 an unusual event consisting of bright bands propagating northwestward was observed. Enhancements in total electron content from ground‐based Global Positioning System receivers were observed collocated with the bright airglow bands. A regional Global Positioning System‐derived total electron content map matches the direction of motion, scale size, and location of these bright bands. Model results includingFregion coupling withEregion structures reproduce the characteristics of the bright bands. Specific conditions in theEregion must exist in order to observe these unusual MSTIDs consisting of propagating bright bands only.
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- Award ID(s):
- 1659304
- PAR ID:
- 10448838
- Publisher / Repository:
- DOI PREFIX: 10.1029
- Date Published:
- Journal Name:
- Journal of Geophysical Research: Space Physics
- Volume:
- 124
- Issue:
- 8
- ISSN:
- 2169-9380
- Page Range / eLocation ID:
- p. 7332-7340
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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