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| Titel |
Doppler radar spectral width broadening due to beamwidth and wind shear |
| VerfasserIn |
G. D. Nastrom |
| 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.786-796 |
| Datensatznummer |
250012841
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| Publikation (Nr.) |
 copernicus.org/angeo-15-786-1997.pdf |
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| Zusammenfassung |
| The spectral width observed by Doppler radars
can be due to several effects including the atmospheric turbulence within the
radar sample volume plus effects associated with the background flow and the
radar geometry and configuration. This study re-examines simple models for the
effects due to finite beamwidth and vertical shear of the horizontal wind.
Analytic solutions of 1- and 2-dimensional models are presented. Comparisons of
the simple 2-dimensional model with numerical integrations of a 3-dimensional
model with a symmetrical Gaussian beam show that the 2-dimensional model is
usually adequate. The solution of the 2-dimensional model gives a formula that
can be applied easily to large data sets. Analysis of the analytic solutions of
the 2-dimensional model for off-vertical beams reveals a term that has not been
included in mathematical formulas for spectral broadening in the past. This term
arises from the simultaneous effects of the changing geometry due to curvature
within a finite beamwidth and the vertical wind shear. The magnitude of this
effect can be comparable to that of the well-known effects of beam-broadening
and wind shear, and since it can have either algebraic sign, it can
significantly reduce (or increase) the expected spectral broadening, although
under typical conditions it is smaller than the beam-broadening effect. The
predictions of this simple model are found to be consistent with observations
from the VHF radar at White Sands Missile Range, NM. |
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