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Ducted Acoustic Gravity Waves in a Nearly Isothermal Atmosphere
The Journal of the Acoustical Society of America, 1967The propagation of acoustic gravity waves is analyzed in atmospheres that have vertical profiles of sound speed squared of the form c2(z) = c2(∞)±Δc2e−2/l, where c2(∞)≫Δc2>0, and both c2(∞) and Δc2 are constant. Ducted wave dispersion relations are obtained from the requirements that the earth's surface act as a rigid boundary to the atmospheric
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EMI potential of radiowaves in presence of atmospheric ducts
International Journal of Electronics, 1990Radiowave propagation measurements were conducted over a smooth-Earth diffraction path (35 km) between Roorkee and Saharanpur for a period of one year. The data collected were analysed with a view to contribute to the understanding of the propagation phenomenon involved and to provide some physical basis for the prediction techniques to be considered ...
R. K. TEWARI, B. S. JASSAL, M. N. ROY
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Analysis of Ultra-short Wave Propagation in Atmospheric Duct
2018 12th International Symposium on Antennas, Propagation and EM Theory (ISAPE), 2018Aiming at the phenomenon of Ship-borne AIS over-the-horizon communication in some area in the Yellow Sea in June 2, 2018, which influenced by atmospheric duct, the atmospheric duct is calculated by using the atmospheric temperature and humidity profiles measured at that time.
Haichuan Tang +3 more
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2007 IEEE Antennas and Propagation Society International Symposium, 2007
An accurate knowledge of radio refractivity is essential in many radar and propagation applications. Especially at low altitudes, radio refractivity can vary considerably with both height and range, heavily affecting the propagation characteristics.
Caglar Yardim +2 more
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An accurate knowledge of radio refractivity is essential in many radar and propagation applications. Especially at low altitudes, radio refractivity can vary considerably with both height and range, heavily affecting the propagation characteristics.
Caglar Yardim +2 more
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Journal of Geophysical Research: Atmospheres, 1989
We present simple examples of gravity wave ducting due to the background thermal and velocity structure in the atmosphere and examine the consequences of such ducts lying in close proximity. The dispersion curves for individual thermal and Doppler ducts exhibit similar behavior, with normal and inverse dispersion at higher and lower frequencies ...
David C. Fritts, Li Yuan
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We present simple examples of gravity wave ducting due to the background thermal and velocity structure in the atmosphere and examine the consequences of such ducts lying in close proximity. The dispersion curves for individual thermal and Doppler ducts exhibit similar behavior, with normal and inverse dispersion at higher and lower frequencies ...
David C. Fritts, Li Yuan
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Inversion for atmosphere duct parameters using real radar sea clutter
Chinese Physics B, 2012This paper addresses the problem of estimating the lower atmospheric refractivity (M profile) under nonstandard propagation conditions frequently encountered in low altitude maritime radar applications. The vertical structure of the refractive environment is modeled using five parameters and the horizontal structure is modeled using five parameters ...
Zheng Sheng, Han-Xian Fang
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Modeling low elevation GPS signal propagation in maritime atmospheric ducts
Journal of Atmospheric and Solar-Terrestrial Physics, 2012Abstract Using the parabolic wave equation (PWE) method, we model low elevation GPS L1 signal propagation in maritime atmospheric ducts. To consider sea surface impedance, roughness, and the effects of earth's curvature, we propose a new initial field model for the GPS PWE split-step solution. On the basis of the comparison between the proposed model
Jinpeng Zhang +4 more
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Influence of atmospheric duct on low-angle radar tracking errors
2016 11th International Symposium on Antennas, Propagation and EM Theory (ISAPE), 2016To investigate the problem of errors for radar tracking low angle target, based on the method of angle tracking and the parabolic equation, a suite of simulated results of elevation errors is presented. The errors of elevation angle have been calculated in conditions including evaporation duct, surface duct, and duct profiles changed with range, which ...
Hongguang Wang +4 more
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Ducted propagation in the atmosphere, from audible sound to infrasound.
The Journal of the Acoustical Society of America, 2010Earth’s atmosphere supports complicated and highly variable winds and temperature gradients. Temperature inversions and wind jets provide ducts in which sound can propagate efficiently to great distances from the source. Due to the intrinsic variability of the atmospheric winds, these sound ducts are also quite variable, both temporally and spatially ...
Roger Waxler +6 more
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Radar detection of missile plumes embedded in elevated atmospheric ducts
1996 IEEE Aerospace Applications Conference. Proceedings, 2002An elevated atmospheric duct results when the refractive index profile of the atmosphere increases then decreases with altitude. Propagation of electromagnetic waves close to the horizontal is similar to propagation in a parallel plate waveguide, effectively increasing detection range.
J.J. Acree, M.W. Maier
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