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| Titel |
Long-period unstable gravity-waves and associated VHF radar echoes |
| VerfasserIn |
R. M. Worthington, L. Thomas |
| 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 ; 15, no. 6 ; Nr. 15, no. 6, S.813-822 |
| Datensatznummer |
250012844
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| Publikation (Nr.) |
 copernicus.org/angeo-15-813-1997.pdf |
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| Zusammenfassung |
| VHF atmospheric radar is used to measure the
wind velocity and radar echo power related to long-period wind perturbations,
including gravity waves, which are observed commonly in the lower stratosphere
and tropopause region, and sometimes in the troposphere. These wind structures
have been identified previously as either inertia-gravity waves, often
associated with jet streams, or mountain waves. At heights of peak wind shear,
imbalances are found between the echo powers of a symmetric pair of radar beams,
which are expected to be equal. The largest of these power differences are found
for conditions of simultaneous high wind shear and high aspect sensitivity. It
is suggested that the effect might arise from tilted specular reflectors or
anisotropic turbulent scatterers, a result of, for example, Kelvin-Helmholtz
instabilities generated by the strong wind shears. This radar power-difference
effect could offer information about the onset of saturation in long-period
waves, and the formation of thin layers of turbulence. |
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