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Regional variations of mesospheric gravity-wave momentum flux over Antarctica
- Source :
- Annales Geophysicae, Vol 24, Pp 81-88 (2006), Annales Geophysicae, Vol 24, Iss 1, Pp 81-88 (2006)
- Publication Year :
- 2006
- Publisher :
- Copernicus Publications, 2006.
-
Abstract
- Images of mesospheric airglow and radar-wind measurements have been combined to estimate the difference in the vertical flux of horizontal momentum carried by high-frequency gravity waves over two dissimilar Antarctic stations. Rothera (67° S, 68° W) is situated in the mountains of the Peninsula near the edge of the wintertime polar vortex. In contrast, Halley (76° S, 27° W), some 1658 km to the southeast, is located on an ice sheet at the edge of the Antarctic Plateau and deep within the polar vortex during winter. The cross-correlation coefficients between the vertical and horizontal wind perturbations were calculated from sodium (Na) airglow imager data collected during the austral winter seasons of 2002 and 2003 at Rothera for comparison with the 2000 and 2001 results from Halley reported previously (Espy et al., 2004). These cross-correlation coefficients were combined with wind-velocity variances from coincident radar measurements to estimate the daily averaged upper-limit of the vertical flux of horizontal momentum due to gravity waves near the peak emission altitude of the Na nightglow layer, 90km. The resulting momentum flux at both stations displayed a large day-to-day variability and showed a marked seasonal rotation from the northwest to the southwest throughout the winter. However, the magnitude of the flux at Rothera was about 4 times larger than that at Halley, suggesting that the differences in the gravity-wave source functions and filtering by the underlying winds at the two stations create significant regional differences in wave forcing on the scale of the station separation.
- Subjects :
- Atmospheric Science
010504 meteorology & atmospheric sciences
Atmospheric circulation
Perturbation (astronomy)
Atmospheric sciences
01 natural sciences
Wind speed
Atmospheric Sciences
Polar vortex
0103 physical sciences
Earth and Planetary Sciences (miscellaneous)
Gravity wave
lcsh:Science
010303 astronomy & astrophysics
Physics::Atmospheric and Oceanic Physics
0105 earth and related environmental sciences
geography
geography.geographical_feature_category
[SDU.OCEAN] Sciences of the Universe [physics]/Ocean, Atmosphere
Momentum transfer
lcsh:QC801-809
Airglow
Geology
Astronomy and Astrophysics
Geophysics
lcsh:QC1-999
lcsh:Geophysics. Cosmic physics
13. Climate action
Space and Planetary Science
Physics::Space Physics
[SDU.STU] Sciences of the Universe [physics]/Earth Sciences
lcsh:Q
Ice sheet
lcsh:Physics
Subjects
Details
- Language :
- English
- ISSN :
- 14320576 and 09927689
- Volume :
- 24
- Database :
- OpenAIRE
- Journal :
- Annales Geophysicae
- Accession number :
- edsair.doi.dedup.....af5e20411b25e937fc6284b3b0b265cf