Results 211 to 220 of about 2,709 (248)
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Simulated Climatology of Atmospheric Ducts Over the Persian Gulf
Boundary-Layer Meteorology, 2005A simulated climatology of ducts in the Persian Gulf area was produced with the MM3 atmospheric model. From November to January ducts were sporadic, land and surface based, shallow and weak. From February to October ducts of all types occurred. In the duct season, spatial and temporal variations were related to the land/sea distribution and to day and ...
B W Atkinson, Atkinson B W
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IEEE Transactions on Antennas and Propagation, 2022
Lixin Guo, Leke Lin, Zong-Hua Ding
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Lixin Guo, Leke Lin, Zong-Hua Ding
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Atmospheric Ducting Effect in Wireless Communications: Challenges and Opportunities
Journal of Communications and Information Networks, 2021Atmospheric ducting has a significant impact on electromagnetic wave propagation. Radio signals that are trapped and guided by the atmospheric duct can travel a much longer distance over the horizon with lower attenuation since the signal power does not spread isotropically through the atmosphere.
Fangfang Liu 0008 +3 more
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FNN-Based Prediction of Wireless Channel with Atmospheric Duct
ICC 2021 - IEEE International Conference on Communications, 2021This paper proposes solutions to channel prediction with atmospheric duct based on feedforward neural network (FNN) modeling. Specifically, FNN-based model is to produce accurate prediction by directly learning from large database rather than depending on any assumption.
Hanzhong Zhang +4 more
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On atmospheric humidity and acoustic ducts
The Journal of the Acoustical Society of America, 2018The development of various propagation ducting phenomena (elevated or surface) has been studied extensively for electromagnetic and electro-optical wave propagation. The influence of changes in temperature, pressure, and humidity gradients on the strength and geometry of the duct in the electromagnetic propagation problem is well-documented, and there ...
Joseph F. Vignola +3 more
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The PE solution of natural waveguides in atmosphere: ducts and elevated ducts
Proceedings of MELECON '94. Mediterranean Electrotechnical Conference, 2002The propagation phenomena through 2D surface duct-to-elevated duct transition is described in terms of parabolic equation (PE) method. The split step marching solution of the PE method is first compared with the reference solutions obtained from Helmholtz wave equation in longitudinally invariant surface duct problem and the excellent agreement between
O. Ercan, L. Sevgi
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Doppler ducting of atmospheric gravity waves
Journal of Geophysical Research: Atmospheres, 1986Atmospheric gravity waves are subject to horizontal ducting in a stably stratified atmosphere that contains levels of wind maximum or minimum, quite apart from any superimposed consequences of vertical variation of stability and quite apart from the existence or otherwise of critical levels.
G. Chimonas, C. O. Hines
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The reflection and ducting of atmospheric acoustic-gravity waves
Canadian Journal of Physics, 1965A simple form is derived for the differential equations governing the propagation of acoustic–gravity waves in an atmosphere whose temperature and horizontal wind velocity vary in an arbitrary manner with height. The condition for wave reflection is discussed in some detail, and the W.K.B. approximate solutions are derived and examined.
M. L. V. Pitteway, C. O. Hines
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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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Analysis of Missing Cloud Echoes in Atmospheric Duct
2019 Cross Strait Quad-Regional Radio Science and Wireless Technology Conference (CSQRWC), 2019In order to analyze the phenomenon of missing cloud echoes of doppler weather radar in Dalian in July 25, 2006, the atmospheric duct is calculated by using the atmospheric temperature and humidity profiles measured at that time. According to the calculated atmospheric duct, the parabolic numerical equation model and radar cloud echo detection distance ...
Hua Wang +3 more
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