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| Titel |
Characteristics of mesospheric gravity waves near the magnetic equator, Brazil, during the SpreadFEx campaign |
| VerfasserIn |
M. J. Taylor, P.-D. Pautet, A. F. Medeiros, R. Buriti, J. Fechine, D. C. Fritts, S. L. Vadas, H. Takahashi, F. T. São Sabbas |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 27, no. 2 ; Nr. 27, no. 2 (2009-02-02), S.461-472 |
| Datensatznummer |
250016387
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| Publikation (Nr.) |
 copernicus.org/angeo-27-461-2009.pdf |
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| Zusammenfassung |
As part of the SpreadFEx campaign, coordinated optical and radio
measurements were made from Brazil to investigate the occurrence and
properties of equatorial Spread F, and to characterize the regional
mesospheric gravity wave field. All-sky image measurements were made from
two sites: Brasilia and Cariri located ~10° S of the magnetic
equator and separated by ~1500 km. In particular, the observations
from Brasilia provided key data in relatively close proximity to expected
convective sources of the gravity waves. High-quality image measurements of
the mesospheric OH emission and the thermospheric OI (630 nm) emission were
made during two consecutive new moon periods (22 September to 9 November
2005) providing extensive data on the occurrence and properties of F-region
depletions and regional measurements of the dominant gravity wave
characteristics at each site.
A total of 120 wave displays were observed, comprising 94 short-period
events and 26 medium-scale gravity waves. The characteristics of the
small-scale waves agreed well with previous gravity wave studies from Brazil
and other sites. However, significant differences in the wave propagation
headings indicate dissimilar source regions for the Brasilia and Cariri
datasets. The observed medium-scale gravity wave events constitute an
important new dataset to study their mesospheric properties at equatorial
latitudes. These data exhibited similar propagation headings to the
short-period events, suggesting they originated from the same source
regions. Medium-scale waves are generally less susceptible to wind filtering
effects and modeling studies utilizing these data have successfully
identified localized regions of strong convection, mainly to the west of
Brasilia, as their most likely sources (Vadas et al., 2009). |
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