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| Titel |
Evidence for tropospheric wind shear excitation of high-phase-speed gravity waves reaching the mesosphere using the ray-tracing technique |
| VerfasserIn |
M. Pramitha, M. Venkat Ratnam, A. Taori, B. V. Krishna Murthy, D. Pallamraju, S. Vijaya Bhaskar Rao |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 15, no. 5 ; Nr. 15, no. 5 (2015-03-10), S.2709-2721 |
| Datensatznummer |
250119510
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| Publikation (Nr.) |
 copernicus.org/acp-15-2709-2015.pdf |
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| Zusammenfassung |
| Sources and propagation characteristics of high-frequency gravity waves
observed in the mesosphere using airglow emissions from Gadanki
(13.5° N, 79.2° E) and Hyderabad (17.5° N, 78.5° E) are
investigated using reverse ray tracing. Wave amplitudes are also traced back,
including both radiative and diffusive damping. The ray tracing is
performed using background temperature and wind data obtained from the MSISE-90
and HWM-07 models, respectively. For the Gadanki region, the suitability of
these models is tested. Further, a climatological model of the background
atmosphere for the Gadanki region has been developed using nearly 30 years
of observations available from a variety of ground-based (MST radar,
radiosondes, MF radar) and rocket- and satellite-borne measurements.
ERA-Interim products are utilized for constructing background parameters corresponding to the meteorological conditions of the
observations.
With the reverse ray-tracing method, the source locations for nine wave events
could be identified to be in the upper troposphere, whereas for five other events the
waves terminated in the mesosphere itself. Uncertainty in locating the terminal points of wave
events in the horizontal direction is estimated to be within 50–100 km and
150–300 km for Gadanki and Hyderabad wave events, respectively. This
uncertainty arises mainly due to non-consideration of the day-to-day
variability in the tidal amplitudes. Prevailing conditions at the terminal
points for each of the 14 events are provided. As no convection
in and around the terminal points is noticed, convection is unlikely to be
the source. Interestingly, large (~9 m s−1km−1) vertical shears
in the horizontal wind are noticed near the ray terminal points (at 10–12 km altitude) and are
thus identified to be the source for generating the observed high-phase-speed, high-frequency gravity waves. |
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