Surface atmospheric duct over Svalbard, Arctic, related to atmospheric and ocean conditions in winter

Zhu, Jieshun; Han, Zhiwei; Kong, Linlin; Zhou, Libo; Cheng, Wei; Bian, Shuangshuang

doi:10.1080/15230430.2022.2072052

Cited by 8 publications

(3 citation statements)

References 55 publications

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“…With the progress in duct research, researchers have found that the phenomenon of atmospheric ducts at sea is not only related to changes in atmospheric stratifications but also closely related to alterations in the underlying sea surface [14][15][16]. The dynamic changes at the sea surface, including the generation and propagation of ocean surface waves and eddies, as well as the distribution of ocean surface temperature, influence the distributions of winds, turbulence, temperature, and humidity in the lower atmosphere via energy and water vapor exchanges between the atmosphere and the sea, thereby affecting the occurrence and characteristics of atmospheric ducts.…”

Section: Introductionmentioning

confidence: 99%

Development of a Numerical Prediction Model for Marine Lower Atmospheric Ducts and Its Evaluation across the South China Sea

Liu,

Zhao,

Zou

et al. 2024

JMSE

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The Coupled Ocean–Atmosphere–Wave–Sediment Transport (COAWST) model serves as the foundation for creating a forecast model to detect lower atmospheric ducts in this study. A set of prediction tests with different forecasting times focusing on the South China Sea domain was conducted to evaluate the short-term forecasting effectiveness of lower atmospheric ducts. The assessment of sounding observation data revealed that the prediction model performed well in predicting the characteristics of all types of ducts. The mean values of the forecasting errors were slightly lower than the reanalysis data but had lower levels of correlation coefficients. At an altitude of about 2000 m, the forecasted error of modified atmospheric refractivity reached peak values and then decreased gradually with increasing altitude. The accuracy of forecasted surface ducts was higher than that of elevated ducts. Noticeable land–sea differences were identified for the spatial distributions of duct characteristics, and the occurrence rates of both the surface and elevated ducts were high at sea. As for the differences among the forecasts of 24, 48, and 72 h ahead, the differences primarily occurred at altitude levels below 20 m and 500 m~1500 m, which are consistent with the differences in the duct height.

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Section: Introductionmentioning

confidence: 99%

Development of a Numerical Prediction Model for Marine Lower Atmospheric Ducts and Its Evaluation across the South China Sea

Liu,

Zhao,

Zou

et al. 2024

JMSE

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show abstract

“…The formation and change in lower atmospheric ducts usually correspond to the temperature inversion process caused by atmospheric motion, such as radiation inversion, sinking inversion, advection inversion, frontal inversion, etc. [9][10][11], for some special lower atmospheric ducts, they can be formed from the sharp drop in humidity [12].…”

Section: Introductionmentioning

confidence: 99%

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

Yang

Wang

2023

Remote Sensing

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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. This paper utilizes data from seven automatic weather stations and five radio-sounding stations to statistically analyze the characteristics of the atmospheric ducts in the northwest region of the South China Sea (SCS). After verifying the practicality of numerical analysis data from NCEP CFSv2 and ECMWF in studying atmospheric ducts using measured data, we analyzed the spatial–temporal distribution characteristics of the height of the regional evaporation duct and the bottom height of the elevated duct. The study found that the NCEP CFSv2 data accurately capture the evaporation duct height and duct occurrence rate in the study area, and the elevated duct bottom height calculated from ERA5 and the measured data have good consistency. The occurrence rate and height of the evaporation duct in coastal stations in the northwest of the SCS vary significantly by month, demonstrating clear monthly distribution patterns; conversely, changes in the Xisha station are minimal, indicating good temporal uniformity. For lower atmospheric ducts, the difference in occurrence rates between 00:00 and 12:00 (UTC) is negligible. The occurrence probability of elevated ducts in the Beibu Gulf area is relatively high, mainly concentrated from January to April, and the Xisha area is dominated by surface ducts without foundation layers, mainly concentrated from June to August. Monsoons play a critical role in the generation and evolution of atmospheric ducts in the northwest of the SCS, with the height of the evaporation duct increasing and the bottom height of the elevated duct decreasing after the onset of the summer monsoon. In the end, we simulated electromagnetic propagation loss under different frequencies and radiation elevation angles in various duct environments within a typical atmospheric duct structure.

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“…Many more studies have used NWP data to examine the refractive index in more limited geographical regions (Atkinson and Zhu, 2006;Sirkova, 2015;Magaldi et al, 2016;Emmanuel et al, 2017). NWP data have been compared with radiosonde data and shown good agreement (von Engeln and Teixeira, 2004;Bech et al, 2007;Zhu et al, 2022).…”

mentioning

confidence: 99%

Observations of anomalous propagation over waters near Sweden

Norin

2022

Preprint

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Abstract. Radio waves propagating in the atmosphere are affected by the prevailing atmospheric state. The state of the atmosphere can cause radio waves to refract more or less towards the ground. When the refractive index of the atmosphere differs from standard atmospheric conditions the propagation is called anomalous. Radars which are affected by anomalous propagation can receive ground clutter far beyond the radar horizon. In this work 4.5 years of data from five operational Swedish C-band dual polarization weather radars are presented. Analyses of the data reveal a strong seasonal cycle and weaker diurnal cycle in ground clutter from coastal regions across nearby waters. The impact of anomalous propagation on ground clutter, measured with horizontal and vertical polarization, was compared but no clear difference was found.

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Surface atmospheric duct over Svalbard, Arctic, related to atmospheric and ocean conditions in winter

Cited by 8 publications

References 55 publications

Development of a Numerical Prediction Model for Marine Lower Atmospheric Ducts and Its Evaluation across the South China Sea

Development of a Numerical Prediction Model for Marine Lower Atmospheric Ducts and Its Evaluation across the South China Sea

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

Observations of anomalous propagation over waters near Sweden

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