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Proceedings with Extended Abstracts (single PDF file) - Radio ...

Proceedings with Extended Abstracts (single PDF file) - Radio ...

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Enhanced resolution applyingpulse scanning and deconvolution:Normal 150-m resolutionFig. 3 Height-time-intensity plot of radar echoes from the troposphere and lowerstratosphere showing sheets and laminae, which are thinner than 150 m and oftenpersist over many tens of minutes. The arrow in the lower panel points to theheight region 15100-16600 m, which is expanded by pulse scanning yieldingenhanced resolution (upper panel).Already 40 years ago Beckmann and Spizzichino had examined the scattering and reflectionfrom rough surfaces of refractive index in the lower atmosphere. The upper-left inset in Fig. 4shows how they introduced the appearance of stable laminae embedded in a turbulent background.There are different scenarios which could explain these laminae (Röttger, 1980);one of these is the establishment of temperature gradients at the edges of turbulent layers, asoriginally proposed by Bolgiano (1968). This original proposal was the basis for many models,which followed subsequently. The generation of sheet ensembles is sketched in the mainpanel of Fig. 4, which base on the mixing of potential temperature gradient by turbulence.Browning and Watkins (1970) mentioned that stretched filaments and double layers resultfrom Kelvin-Helmhotz-Instability as shown in the upper right-hand panel of Fig.4. Röttger(1987) implemented a scheme on the decay of turbulence into multiple temperature sheets.Modified for VHF radar by Röttger, 1980Fig. 4 Sheets, laminae or stretched filaments in a turbulent background.(Beckmann and Spizzichino, 1963 (upper left); Browning and Watkins, 1970(upper right) and others referenced therein; Peltier et al., 1978; Röttger, 1981).451

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