Turbulence characteristics in the tropical mesosphere as obtained by MST radar at Gadanki (13.5° N, 79.2° E)
Turbulent kinetic energy dissipation rates (<i>ε</i>) and eddy diffusion coefficients (K<sub>z</sub>) in the tropical mesosphere over Gadanki (13.5° N, 79.2° E), estimated from Doppler widths of MST radar echoes (vertical beam), observed over a 3-year perio...
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2001-08-01
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| Series: | Annales Geophysicae |
| Online Access: | https://www.ann-geophys.net/19/1019/2001/angeo-19-1019-2001.pdf |
| _version_ | 1818505653393555456 |
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| author | M. N. Sasi L. Vijayan |
| author_facet | M. N. Sasi L. Vijayan |
| author_sort | M. N. Sasi |
| collection | DOAJ |
| description | Turbulent kinetic energy
dissipation rates (<i>ε</i>) and eddy diffusion coefficients (K<sub>z</sub>)
in the tropical mesosphere over Gadanki (13.5° N, 79.2° E), estimated from
Doppler widths of MST radar echoes (vertical beam), observed over a 3-year
period, show a seasonal variation with a dominant summer maximum. The observed
seasonal variation of <i>ε</i> and K<sub>z</sub> in the
mesosphere is only partially consistent with that of gravity wave activity
inferred from mesospheric winds and temperatures measured by rockets for a
period of 9 years at Trivandrum (8.5° N, 77° E) (which shows two equinox and
one summer maxima) lying close to Gadanki. The summer maximum of mesospheric
<i>ε</i> and K<sub>z</sub> values appears to be related to the
enhanced gravity wave activity over the low-latitude Indian subcontinent during
the southwest monsoon period (June – September). Both <i>ε</i> and K<sub>z</sub>
in the mesosphere over Gadanki show an increase with an increase in height
during all seasons. The absolute values of observed <i>ε</i> and K<sub>z</sub>
in the mesosphere (above ~80 km) does not show significant differences from
those reported for high latitudes. Comparison of observed K<sub>z </sub>values
during the winter above Gadanki with those over Arecibo (18.5° N, 66° W)
shows that they are not significantly different from each other above the ~80
km altitude.<br><br><b>Key words. </b>Meteorology and
atmospheric dynamics (middle atmosphere dynamics; tropical meteorology; wave
and tides) |
| first_indexed | 2024-12-10T21:53:48Z |
| format | Article |
| id | doaj.art-5fbaea6354084b30a37c229465401200 |
| institution | Directory Open Access Journal |
| issn | 0992-7689 1432-0576 |
| language | English |
| last_indexed | 2024-12-10T21:53:48Z |
| publishDate | 2001-08-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Annales Geophysicae |
| spelling | doaj.art-5fbaea6354084b30a37c2294654012002022-12-22T01:32:07ZengCopernicus PublicationsAnnales Geophysicae0992-76891432-05762001-08-01191019102510.5194/angeo-19-1019-2001Turbulence characteristics in the tropical mesosphere as obtained by MST radar at Gadanki (13.5° N, 79.2° E)M. N. Sasi0L. Vijayan1Space Physics Laboratory, Vikram Sarabhai Space Centre, Trivandrum 695022, IndiaSpace Physics Laboratory, Vikram Sarabhai Space Centre, Trivandrum 695022, IndiaTurbulent kinetic energy dissipation rates (<i>ε</i>) and eddy diffusion coefficients (K<sub>z</sub>) in the tropical mesosphere over Gadanki (13.5° N, 79.2° E), estimated from Doppler widths of MST radar echoes (vertical beam), observed over a 3-year period, show a seasonal variation with a dominant summer maximum. The observed seasonal variation of <i>ε</i> and K<sub>z</sub> in the mesosphere is only partially consistent with that of gravity wave activity inferred from mesospheric winds and temperatures measured by rockets for a period of 9 years at Trivandrum (8.5° N, 77° E) (which shows two equinox and one summer maxima) lying close to Gadanki. The summer maximum of mesospheric <i>ε</i> and K<sub>z</sub> values appears to be related to the enhanced gravity wave activity over the low-latitude Indian subcontinent during the southwest monsoon period (June – September). Both <i>ε</i> and K<sub>z</sub> in the mesosphere over Gadanki show an increase with an increase in height during all seasons. The absolute values of observed <i>ε</i> and K<sub>z</sub> in the mesosphere (above ~80 km) does not show significant differences from those reported for high latitudes. Comparison of observed K<sub>z </sub>values during the winter above Gadanki with those over Arecibo (18.5° N, 66° W) shows that they are not significantly different from each other above the ~80 km altitude.<br><br><b>Key words. </b>Meteorology and atmospheric dynamics (middle atmosphere dynamics; tropical meteorology; wave and tides)https://www.ann-geophys.net/19/1019/2001/angeo-19-1019-2001.pdf |
| spellingShingle | M. N. Sasi L. Vijayan Turbulence characteristics in the tropical mesosphere as obtained by MST radar at Gadanki (13.5° N, 79.2° E) Annales Geophysicae |
| title | Turbulence characteristics in the tropical mesosphere as obtained by MST radar at Gadanki (13.5° N, 79.2° E) |
| title_full | Turbulence characteristics in the tropical mesosphere as obtained by MST radar at Gadanki (13.5° N, 79.2° E) |
| title_fullStr | Turbulence characteristics in the tropical mesosphere as obtained by MST radar at Gadanki (13.5° N, 79.2° E) |
| title_full_unstemmed | Turbulence characteristics in the tropical mesosphere as obtained by MST radar at Gadanki (13.5° N, 79.2° E) |
| title_short | Turbulence characteristics in the tropical mesosphere as obtained by MST radar at Gadanki (13.5° N, 79.2° E) |
| title_sort | turbulence characteristics in the tropical mesosphere as obtained by mst radar at gadanki 13 5° n 79 2° e |
| url | https://www.ann-geophys.net/19/1019/2001/angeo-19-1019-2001.pdf |
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