The Diurnal Variation of the Evaporation Duct Height and Its Relationship With Environmental Variables in the South China Sea

Huang, Lang; Zhao, Xiaofeng; Liu, Yudi; Yang, Pinglv; Ding, Jiaqi; Zhou, Zeming

doi:10.1109/tap.2022.3191160

Cited by 8 publications

(11 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The temporal resolution of the ERA5 dataset is 1 h and the horizontal resolution is 0.25°× 0.25°. ERA5 data have been widely used and verified suitable for studies on evaporation duct distributions (Sirkova, 2015;Huang et al, 2022;Wang et al, 2022a;Wang et al, 2022b). The parameters of AT at 2-m height, AP, WS at 10-m height, RH at 1000 hPa, and sea surface temperature (SST) were extracted to simulate the EDH distributions during the measurements.…”

Section: Reanalysis Datamentioning

confidence: 99%

“…The temporal and spatial distribution characteristics of evaporation duct show strong differences in different sea areas (Shi et al, 2015b;Sirkova, 2015;Yang et al, 2016;Zhang et al, 2016;Yang et al, 2022a;Huang et al, 2022). Lying between mainland China and the Korean Peninsula, the Yellow Sea is one of the largest areas of continental shelf shallow water that provides rich fishing grounds and oil resources.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Long-term over-the-horizon microwave channel measurements and statistical analysis in evaporation ducts over the Yellow Sea

et al. 2023

View full text Add to dashboard Cite

Maritime high-speed over-the-horizon wireless communication is realizable through evaporation ducts. Detailed measurement, analysis, and modeling of duct channels are essential for application of this communication technique. In this paper, X-band electromagnetic (EM) wave propagation systems were developed and deployed for a 133-km over-the-horizon microwave link in coastal areas of the Yellow Sea. The propagation length was 7.7 times the line-of-sight length. Measurement results including the path loss (PL) and meteorological data were obtained during a 54-day period in autumn 2021. The long-term channel results were analyzed on the basis of statistical analysis and model simulations. Results showed that our measurement system, with a maximum measurable power loss of 200 dB, had connected with a probability of 56.2% during the measurement period. Model simulation showed that evaporation duct environments are not ideal in autumn, with an average evaporation duct height (EDH) of 10.6 m. The land breeze in autumn introduced dry and cold air to the link, which could promote evaporation of seawater and reduce PL by approximately 40 dB. Annual spatiotemporal characteristics of EDH showed that evaporation ducts are most suitable for over-the-horizon communication in spring, especially May.

show abstract

Section: Reanalysis Datamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Long-term over-the-horizon microwave channel measurements and statistical analysis in evaporation ducts over the Yellow Sea

et al. 2023

View full text Add to dashboard Cite

show abstract

“…Frederickson et al [6] used NCEP reanalysis data in conjunction with the NPS evaporation duct model proposed by the US Naval Postgraduate School to establish a global evaporation duct database with higher spatial resolution. Subsequently, this method has been widely applied and has become an important means for researchers to diagnose and analyze the environmental characteristics of evaporation ducts in global seas [4,[7][8][9] .…”

Section: Introductionmentioning

confidence: 99%

Spatiotemporal Characteristics of the Evaporation Duct in the Kuroshio Extension

Gao,

Zhang,

Hong

et al. 2024

J. Phys.: Conf. Ser.

View full text Add to dashboard Cite

The evaporation duct over the sea affects the propagation of electromagnetic waves, impacts the performance of electromagnetic systems accordingly, such as the shipborne radars. In order to reveal the spatiotemporal variations of the evaporation duct in the Kuroshio Extension (KE) region, where is one of the most intense air-sea interaction regions, the study utilized a 30-year ERA5 reanalysis dataset (from 1993 to 2022) and conducted statistical analysis on the monthly, seasonal variations and spatial distribution characteristics of the evaporation duct based on the NPS evaporation duct diagnostic model. The results enrich the database of maritime evaporation duct characteristics and improve the resolution and accuracy compared to previous studies.

show abstract

“…It is formed because the atmospheric humidity on the sea surface decreases rapidly with an increasing altitude under the marine atmospheric boundary layer (MABL), resulting in an abnormal refractive index of the atmosphere [1], a phenomenon that makes the distribution of the refractive index near the sea surface nonuniform. Evaporation ducts alter the propagation trajectory of electromagnetic (EM) waves through the atmosphere so that the EM waves can realize beyond-horizon detection and beyond-horizon communication in the duct layer and can obtain a detection blind zone [2][3][4]. Research on evaporation ducts can provide a basis for the detection of the marine radio wave environment and research on radio wave propagation characteristics and effectively avoid the EM wave path loss caused by the evaporation duct in the atmospheric environment [5,6].…”

Section: Introductionmentioning

confidence: 99%

Research on a Multimodel Fusion Diagnosis Method for Evaporation Ducts in the East China Sea

Zhang,

Qiu,

Fan

et al. 2023

Sensors

View full text Add to dashboard Cite

Evaporation ducts are abnormal states of the atmosphere in the air–sea boundary layer that directly affect the propagation trajectory of electromagnetic (EM) waves. Therefore, an accurate diagnosis of the evaporation duct height (EDH) is important for studying the propagation trajectory of EM waves in evaporation ducts. Most evaporation duct models (EDMs) based on the Monin–Obukhov similarity theory are empirical methods. Different EDMs have different levels of environmental adaptability. Evaporation duct diagnosis methods based on machine learning methods only consider the mathematical relationship between data and do not explore the physical mechanism of evaporation ducts. To solve the above problems, this study observed the meteorological and hydrological parameters of the five layers of the low-altitude atmosphere in the East China Sea on board the research vessel Xiangyanghong 18 in April 2021 and obtained the atmospheric refractivity profile. An evaporation duct multimodel fusion diagnosis method (MMF) based on a library for support vector machines (LIBSVM) is proposed. First, based on the observed meteorological and hydrological data, the differences between the EDH diagnosis results of different EDMs and MMF were analyzed. When ASTD ≥ 0, the average errors of the diagnostic results of BYC, NPS, NWA, NRL, LKB, and MMF are 2.57 m, 2.92 m, 2.67 m, 3.27 m, 2.57 m, and 0.24 m, respectively. When ASTD < 0, the average errors are 2.95 m, 2.94 m, 2.98 m, 2.99 m, 2.97 m, and 0.41 m, respectively. Then, the EM wave path loss accuracy analysis was performed on the EDH diagnosis results of the NPS model and the MMF. When ASTD ≥ 0, the average path loss errors of the NPS model and MMF are 5.44 dB and 2.74 dB, respectively. When ASTD < 0, the average errors are 5.21 dB and 3.46 dB, respectively. The results show that the MMF is suitable for EDH diagnosis, and the diagnosis accuracy is higher than other models.

show abstract

The Diurnal Variation of the Evaporation Duct Height and Its Relationship With Environmental Variables in the South China Sea

Cited by 8 publications

References 28 publications

Long-term over-the-horizon microwave channel measurements and statistical analysis in evaporation ducts over the Yellow Sea

Long-term over-the-horizon microwave channel measurements and statistical analysis in evaporation ducts over the Yellow Sea

Spatiotemporal Characteristics of the Evaporation Duct in the Kuroshio Extension

Research on a Multimodel Fusion Diagnosis Method for Evaporation Ducts in the East China Sea

Contact Info

Product

Resources

About