Results 21 to 30 of about 1,274 (202)

Validation of atmospheric evaporation duct in the eastern Indian Ocean [PDF]

Frontiers in Earth Science
An atmospheric duct is an anomalous atmospheric structural phenomenon that causes trap refraction in the troposphere to change the propagation paths and ranges of electromagnetic waves, thereby increasing the detection distances of radar and other ...
Zhe Qi, Zhe Qi, Huabin Mao, Huabin Mao, Chunhua Qiu, Yongfeng Qi, Yongfeng Qi   +6 more
doaj   +2 more sources

XGB Model : Research on Evaporation Duct Height Prediction Based on XGBoost Algorithm [PDF]

Radioengineering, 2020
Evaporation duct is a specific atmospheric structure at sea, which has an important influence on the propagation path of electromagnetic waves (EW).
W. P. Zhao, J. Li, J. Zhao, D. Zhao, J. Lu, X. Wang   +5 more
doaj   +3 more sources

The Effects of Rainfall on Over-the-Horizon Propagation in the Evaporation Duct over the South China Sea

Remote Sensing, 2022
The evaporation duct (ED) is generated by the evaporation of seawater and can be an influential factor of electromagnetic (EM)-wave propagation. Rainfall also affects atmospheric factors and EM-wave propagation.
Fan Yang, Kunde Yang, Yang Shi, Shuwen Wang, Hao Zhang, Yaming Zhao   +5 more
doaj   +2 more sources

Variability of Silver Fir Needle (Abies alba Mill.) Anatomical Features in the Southeast Europe Natural Populations [PDF]

Plants
The survival of marginal/peripheral silver fir (Abies alba Mill.) populations in the broader region of Southeast Europe is endangered due to climate change and population decline. This study aimed to determine the level and pattern of variability for the
Vladan Popović, Aleksandar Lučić, Ljubinko Rakonjac, Aleksandar Vemić, Sanja Jovanović, Biljana M. Nikolić, Danijela Miljković   +6 more
doaj   +2 more sources

On the Possibility of Detecting Evaporation Ducts Through GNSS Reflectometry

Remote Sensing
An evaporation duct is a kind of atmospheric event with a refractive index exceeding the curvature of the Earth, which mostly exists on the ocean surface.
Fu Li, Yueqiang Sun, Xianyi Wang, Junming Xia, Feixiong Huang, Qifei Du, Weihua Bai, Zhuoyan Wang, Tongsheng Qiu   +8 more
doaj   +2 more sources

ENSO-Modulated Spatio-Temporal Variability of Evaporation Duct Height in the South China Sea

Journal of Marine Science and Engineering
The evaporation duct, formed above the ocean surface by sharp vertical gradients of humidity, would significantly influence electromagnetic wave propagation.
Jingju Wang, Shi Wang, Xiaoju Pan, Shaoqing Zhang, Xing Liu, Yimin Zhang, Guangyu Yi, Ziru Li   +7 more
doaj   +2 more sources

A Comparison of the Machine Learning Algorithm for Evaporation Duct Estimation

Radioengineering, 2013
In this research, a comparison of the relevance vector machine (RVM), least square support vector machine (LSSVM) and the radial basis function neural network (RBFNN) for evaporation duct estimation are presented.
C. Yang
doaj   +1 more source

Atmospheric Ducts and Their Electromagnetic Propagation Characteristics in the Northwestern South China Sea

Remote Sensing, 2023
The propagation of electromagnetic waves beyond the line of sight can be caused by atmospheric ducts, which are significant concerns in the fields of radar and communication.
Ning Yang, Debin Su, Tao Wang
doaj   +1 more source

Ray Tracing and Applications to an Evaporation Duct Model Based on Data from Oceanographic Buoy Sensors

Journal of Microwaves, Optoelectronics and Electromagnetic Applications
The two-dimensional ray tracing method allows an easy and fast modeling of tropospheric propagation in the microwave frequency range. A version of this method that determines ray trajectories, amplitudes and delays of the electromagnetic field, as well ...
Leonardo L. Freitas, Emanoel Costa
doaj   +2 more sources

Experimental Analysis of Atmospheric Ducts and Navigation Radar Over-the-Horizon Detection

Remote Sensing, 2022
Since the height of sea detection radar antenna and ship targets is relatively low, it is generally believed that its over-the-horizon detection is mainly caused by the evaporation duct at sea.
Li-Feng Huang, Cheng-Guo Liu, Hong-Guang Wang, Qing-Lin Zhu, Li-Jun Zhang, Jie Han, Yu-Sheng Zhang, Qian-Nan Wang   +7 more
doaj   +1 more source