Spatial-temporal analysis of inter tropical discontinuity influence on radio signal behavior in Nigeria

IF 1.6 4区地球科学 Q3 ASTRONOMY & ASTROPHYSICS Radio Science Pub Date : 2024-11-01 DOI:10.1029/2024RS008006

I. Emmanuel;O. S. Ojo;G. O. Emmanuel;K. D. Adedayo

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Abstract

This study investigates the influence of the inter tropical discontinuity (ITD) on radio signal behavior over Nigeria using ERA5 data from the Copernicus Climate Change Services (C3S). Monthly variations of refractivity gradient values and ITD movements were analyzed through spatial distribution and wavelet coherence. Results indicate that the ITD position significantly affects refractivity gradient values. Below the ITD, values range from − 5 to −110 N-units/km, while above the ITD, values are less than −110 N-units/km, indicating predominant ducting conditions. The ITD shifts latitudinally from a peak at 20° in August to a low at 5° in December. Correlation coefficients between ITD position and refractivity gradient values in different climatic regions (Am, Aw, BSh, BWh) range from −0.920 to 0.844, emphasizing the significant influence of ITD on atmospheric conditions in these regions. Statistical analysis using the wavelet coherence method demonstrates a strong connection between ITD and refractivity gradient, with coherence values indicating synchronization at specific frequency-time pairs.

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热带间断性对尼日利亚无线电信号行为影响的时空分析

利用哥白尼气候变化服务（C3S）的ERA5数据，研究了热带间断性（ITD）对尼日利亚上空无线电信号行为的影响。利用空间分布和小波相干分析了折射率梯度值和过渡段运动的月变化。结果表明，过渡段位置对折射率梯度值有显著影响。过渡段以下的值在−5 ~−110 n -单位/km之间，过渡段以上的值小于−110 n -单位/km，表明导管条件优越。过渡段从8月20°的峰值向12月5°的低点转变。不同气候区（Am、Aw、BSh、BWh）过渡段位置与折射率梯度值的相关系数为- 0.920 ~ 0.844，表明过渡段对这些地区大气条件的影响显著。利用小波相干性方法的统计分析表明，过渡段与折射率梯度之间存在很强的联系，相干性值表示特定频率时间对的同步。

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来源期刊

Radio Science 工程技术-地球化学与地球物理

CiteScore

3.30

自引率

12.50%

发文量

112

审稿时长

1 months

期刊介绍： Radio Science (RDS) publishes original scientific contributions on radio-frequency electromagnetic-propagation and its applications. Contributions covering measurement, modelling, prediction and forecasting techniques pertinent to fields and waves - including antennas, signals and systems, the terrestrial and space environment and radio propagation problems in radio astronomy - are welcome. Contributions may address propagation through, interaction with, and remote sensing of structures, geophysical media, plasmas, and materials, as well as the application of radio frequency electromagnetic techniques to remote sensing of the Earth and other bodies in the solar system.