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...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
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 |
| Summary: | 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) |
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| ISSN: | 0992-7689 1432-0576 |