Results 281 to 290 of about 43,943 (330)

Analysis of Missing Cloud Echoes in Atmospheric Duct

2019 Cross Strait Quad-Regional Radio Science and Wireless Technology Conference (CSQRWC), 2019
In 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, Yunbo Li, Haichuan Tang, Lin Jiao   +3 more
openaire   +1 more source

Design of an ocean atmospheric duct signal processor

2010 International Symposium on Intelligent Signal Processing and Communication Systems, 2010
The atmospheric refractive section plane retrieved from radar sea clutter is of importance for the might enhancement of military naval radar. In this paper, an atmospheric duct signal processor with hardware of an intermediate-frequency board and a high-speed DSP board, besides the arithmetic of clutter suppression and sea clutter extraction, have been
null Li XueHua, null He ZiShu, null He JianXin, null Duan ShouYuan   +3 more
openaire   +1 more source

The reflection and ducting of atmospheric acoustic-gravity waves

Canadian Journal of Physics, 1965
A 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
openaire   +1 more source

Simulated Climatology of Atmospheric Ducts Over the Persian Gulf

Boundary-Layer Meteorology, 2005
A 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 ...
M. Zhu, B. W. Atkinson
openaire   +1 more source

Predicting Duct Height in Atmospheric Duct by Neural Network

Advanced Materials Research, 2012
The experimental data show that Southeast China Sea has a higher occurrence probability of atmospheric duct. Based on modified refractivity, Neural Network was introduced to predict the duct height of evaporation duct and analyze the anomalous propagation of electromagnetic wave in marine evaporation duct.
openaire   +1 more source

Prediction of Electromagnetic Shadow Zone in Atmospheric Duct

The 2006 4th Asia-Pacific Conference on Environmental Electromagnetics, 2006
Electromagnetic shadow zone is an important propagation character which is caused by atmospheric duct. The purpose of this paper is to find a method to predict such shadow zone. Two numerical models are introduced in this paper. The first one is used to predict the top hole in evaporation duct. The other one is to predict the skip zone in surface duct.
Jiao Lin, Wang Hua, Zhang Yong-gang
openaire   +1 more source

Background covariance of atmospheric duct properties based on ensembles

2015 USNC-URSI Radio Science Meeting (Joint with AP-S Symposium), 2015
In Refractivity Data Fusion (RDF), the Cartesian representation of refractivity calculated from the Numerical Weather Prediction (NWP) output is mapped into a set of 2-dimensional diagnostic variables which are surfaces over the NWP domain. The diagnostic parameters (e.g. duct base height, duct strength, duct thickness, evaporation duct height) include
Neil D. Gordon, Ana K. Ascencio, Ted Rogers, Tracy Haack, Allen Zhao   +4 more
openaire   +1 more source

Modeling on multi‐eigenpath channel in marine atmospheric duct

Radio Science, 2009
A multi‐eigenpath channel model is proposed to simulate the microwave transhorizon communication signal in marine atmospheric duct environment. The channel model identifies the relation between multiperiodical delay components and subeigenpath components. The simplified algorithm of subeigen signal is proposed on the basis on signal‐to‐multipath ratio.
Xiao‐long Zhao, Ji‐ying Huang, Shu‐hong Gong   +2 more
openaire   +1 more source

A narrow-angle parabolic equation model in atmospheric ducts

2016 11th International Symposium on Antennas, Propagation and EM Theory (ISAPE), 2016
In this paper, the narrow-angle parabolic equation (NAPE) model applied on atmospheric ducts is solved by using the improved discrete mixed Fourier transform (IDMFT) method which is an efficient form of the split-step Fourier transform (SSFT) algorithm under the impedance boundary conditions.
Yajiao Wang, Lixin Guo, Qingliang Li
openaire   +1 more source

Remote sensing of atmospheric duct parameters using simulated annealing

Chinese Physics B, 2011
Simulated annealing is one of the robust optimization schemes. Simulated annealing mimics the annealing process of the slow cooling of a heated metal to reach a stable minimum energy state. In this paper, we adopt simulated annealing to study the problem of the remote sensing of atmospheric duct parameters for two different geometries of propagation ...
Xiao-Feng Zhao, Si-Xun Huang, Jie Xiang, Wei-Lai Shi   +3 more
openaire   +1 more source