American Journal of Electrical and Computer Engineering

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Comparative Analysis of Surface Refractivity Variations in the Sahel and Coastal Zones of Nigeria

Received: 15 April 2023    Accepted: 4 May 2023    Published: 10 June 2023
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Abstract

Variation in Surface Refractivity N is largely influenced by changes in some meteorological parameters such as air temperature, relative humidity, and pressure. These parameters are more accurate when measured locally due to their temporal and spatial variations. The research studies and verifies the contributions of the dry and wet term components of surface radio refractivity. The research focuses on the comparison of surface refractivity variations in two geoclimatic zones of Nigeria. The study reveals that the Sahel and Coastal zones have dissimilar distinct weather conditions and consequently diverse variational pattern of their surface refractivities diurnally and seasonally. The diurnal values of surface refractivity vary moderately on typical sunny days with average values of about 345-391 N-units and 275-314 N-units in the Coastal and Sahel respectively. Wider daily variations were observed during the rainy season in both geoclimatic zones due to frequent rainfalls, especially in the Coastal Stations. The average daily refractivity in the Coastal and Sahel during the rainy seasons are 339-390 and 311-384 N-units respectively. Analysis of the results obtained indicates that the annual mean of the ITU-R recommendation underestimates surface refractivity by 11-15% across the coastal stations and by 5-10% across the Sahel zone. The derived values for each station would be useful for radio engineers in the design and optimization of terrestrial radio links.

DOI 10.11648/j.ajece.20230701.12
Published in American Journal of Electrical and Computer Engineering (Volume 7, Issue 1, June 2023)
Page(s) 10-18
Creative Commons

This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited.

Copyright

Copyright © The Author(s), 2024. Published by Science Publishing Group

Keywords

Surface Refractivity, Geoclimatic Zones, Sahel Zone, Coastal Zone

References
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[2] Sunday Emmanuel Falodun and Yusuf Babatunde Lawal, “Investigation of Non-standard Refraction in a Coastal Area of Nigeria Using Radiosonde Data”, FUTA Journal of Research in Sciences, Vol. 11, pp 358, 2015.
[3] International Telecommunication Union, Radio Section (ITU-R), “Radio Refractive Index: its formula and refractivity data”, Rec. P 453-9, 2003.
[4] Yusuf Babatunde Lawal and Emmanuel Temitope Omotoso, “Investigation of Point Refractivity Gradient and Geoclimatic Factor at 70 m Altitude in Yenagoa, Nigeria”, Journal of the Nigerian Society of Physical Sciences, Vol. 5, Issue 1, pp 1081, 2023, https://doi.org/10.46481/jnsps.2023.1081
[5] International Telecommunication Union, Radio Section (ITU-R), “Radio Refractive Index: Its formula and refractivity data”, Rec. P. 453-11, pp. 8, 2015.
[6] European Centre for Medium-Range Weather Forecast (ECMWF), ERA-5 2019, Reanalysis Era-5 data at Pressure Levels. Available at https://cds.climate.copernicus.eu/cdsapp#!/dataset/reanalysis-era5-pressure-levels?tab=overview
[7] Adewumi Oluwatoyin Ayo, Pius Adewale Owolawi and Joseph Sunday Ojo, "Performance of ARIMA modelling on sub-tropical rain attenuation at Ka-band terrestrial link in Kwazulu-Natal, South Africa," 2021 IEEE International Conference on Microwaves, Antennas, Communications and Electronic Systems (COMCAS), Tel Aviv, Israel, pp. 389-394, 2021, doi: 10.1109/COMCAS52219.2021.9629001.
[8] Afullo T. J., Motsoela T., Molotsi D. F., “Refractivity gradient and k-factor in Botswana” Radio Africa, pp. 107-110, 1999.
[9] Olaniran, O. J., and Sumner, G. N., “A Study of Climatic Variability in Nigeria Based on the Onset, Retreat, and Length of the Rainy Season”, International Journal of Climatology, Vol. 9, pp. 253-269, 1989.
[10] Lawal Salami Lasisi, “Economically Sustainable Public Security and Emergency Network Exploiting a Broadband Communications Satellite”, PhD Thesis submitted to Department of Engineering & Design School of Engineering and Informatics University of Sussex, Brighton, 2014. Available online via Sussex Research Online at http://sro.sussex.ac.uk/
[11] Smith E. K. and Weintraub S., "The Constants in the Equation for Atmospheric Refractive Index at Radio Frequencies”, Proceedings of the IRE, vol. 41, no. 8, pp. 1035-1037, Aug. 1953, doi: 10.1109/JRPROC.1953.274297.
[12] International Telecommunication Union, Radio Section (ITU-R), “Propagation data and prediction methods required for the design of terrestrial line-of-sight systems”, Rec. P. 530-15, pp. 2, 2013.
[13] Igwe K. C and Adimula I. A, “Variation of Surface Radio Refractivity and Radio Refractivity Index Gradient in the sub-sahel”, Nigerian Journal of Space Research, Vol. 6, pp. 135- 144, 2009.
[14] Okoro, O. N., and Agbo, G. A., “The effect of variation of meteorological parameters on the tropospheric radio refractivity for minna”, Global Journal of Science Frontier Research, Vol. 12, 1969.
[15] Isikwue, B. C., Kwen Y. A and Chamegh T. M., “Variations in the tropospheric surface refractivity over Makurdi, Nigeria”, Research Journal of Earth and Planetary Sciences Vol. 3, Issue 2, pp. 50-59, 2013.
[16] The African Bird Club, “The Geography of Nigeria, UK registered charity club” 1184309 [Online]. Available: https://www.africanbirdclub.org/countries/Nigeria/geography
[17] Yusuf Babatunde Lawal, Joseph Sunday Ojo and Sunday Emmanuel Falodun, “Variability and Trends in Rain Height retrieved from GPM and implications on rain-induced attenuation over Nigeria”, Heliyon, Elsevier Ltd, Vol. 7, 2021, https://doi.org/10.1016/j.heliyon.2021.e08108
[18] Yusuf Babatunde Lawal, Joseph Sunday Ojo and Sunday Emmanuel Falodun, “Rain Height Statistics From GPM Data For Satellite Communications Systems In Nigeria”, Institute of Physics (IOP) Conference Series: Earth and Environmental Science, pp. 655, 2021, doi: 10.1088/1755-1315/655/1/012038.
[19] Taiwo A., Utah E. U., Sombo T. E., “Monthly Variation and Annual Trends of Rainfall across Major Climatic Zones in Nigeria”, IOSR Journal of Applied Physics, Vol. 10, Issue 4, pp. 15-28, 2018, e-ISSN: 2278-4861,
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Cite This Article
  • APA Style

    Yusuf Babatunde Lawal, Joseph Babatunde Dada. (2023). Comparative Analysis of Surface Refractivity Variations in the Sahel and Coastal Zones of Nigeria. American Journal of Electrical and Computer Engineering, 7(1), 10-18. https://doi.org/10.11648/j.ajece.20230701.12

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    ACS Style

    Yusuf Babatunde Lawal; Joseph Babatunde Dada. Comparative Analysis of Surface Refractivity Variations in the Sahel and Coastal Zones of Nigeria. Am. J. Electr. Comput. Eng. 2023, 7(1), 10-18. doi: 10.11648/j.ajece.20230701.12

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    AMA Style

    Yusuf Babatunde Lawal, Joseph Babatunde Dada. Comparative Analysis of Surface Refractivity Variations in the Sahel and Coastal Zones of Nigeria. Am J Electr Comput Eng. 2023;7(1):10-18. doi: 10.11648/j.ajece.20230701.12

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  • @article{10.11648/j.ajece.20230701.12,
      author = {Yusuf Babatunde Lawal and Joseph Babatunde Dada},
      title = {Comparative Analysis of Surface Refractivity Variations in the Sahel and Coastal Zones of Nigeria},
      journal = {American Journal of Electrical and Computer Engineering},
      volume = {7},
      number = {1},
      pages = {10-18},
      doi = {10.11648/j.ajece.20230701.12},
      url = {https://doi.org/10.11648/j.ajece.20230701.12},
      eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ajece.20230701.12},
      abstract = {Variation in Surface Refractivity N is largely influenced by changes in some meteorological parameters such as air temperature, relative humidity, and pressure. These parameters are more accurate when measured locally due to their temporal and spatial variations. The research studies and verifies the contributions of the dry and wet term components of surface radio refractivity. The research focuses on the comparison of surface refractivity variations in two geoclimatic zones of Nigeria. The study reveals that the Sahel and Coastal zones have dissimilar distinct weather conditions and consequently diverse variational pattern of their surface refractivities diurnally and seasonally. The diurnal values of surface refractivity vary moderately on typical sunny days with average values of about 345-391 N-units and 275-314 N-units in the Coastal and Sahel respectively. Wider daily variations were observed during the rainy season in both geoclimatic zones due to frequent rainfalls, especially in the Coastal Stations. The average daily refractivity in the Coastal and Sahel during the rainy seasons are 339-390 and 311-384 N-units respectively. Analysis of the results obtained indicates that the annual mean of the ITU-R recommendation underestimates surface refractivity by 11-15% across the coastal stations and by 5-10% across the Sahel zone. The derived values for each station would be useful for radio engineers in the design and optimization of terrestrial radio links.},
     year = {2023}
    }
    

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    T1  - Comparative Analysis of Surface Refractivity Variations in the Sahel and Coastal Zones of Nigeria
    AU  - Yusuf Babatunde Lawal
    AU  - Joseph Babatunde Dada
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    N1  - https://doi.org/10.11648/j.ajece.20230701.12
    DO  - 10.11648/j.ajece.20230701.12
    T2  - American Journal of Electrical and Computer Engineering
    JF  - American Journal of Electrical and Computer Engineering
    JO  - American Journal of Electrical and Computer Engineering
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    EP  - 18
    PB  - Science Publishing Group
    SN  - 2640-0502
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    AB  - Variation in Surface Refractivity N is largely influenced by changes in some meteorological parameters such as air temperature, relative humidity, and pressure. These parameters are more accurate when measured locally due to their temporal and spatial variations. The research studies and verifies the contributions of the dry and wet term components of surface radio refractivity. The research focuses on the comparison of surface refractivity variations in two geoclimatic zones of Nigeria. The study reveals that the Sahel and Coastal zones have dissimilar distinct weather conditions and consequently diverse variational pattern of their surface refractivities diurnally and seasonally. The diurnal values of surface refractivity vary moderately on typical sunny days with average values of about 345-391 N-units and 275-314 N-units in the Coastal and Sahel respectively. Wider daily variations were observed during the rainy season in both geoclimatic zones due to frequent rainfalls, especially in the Coastal Stations. The average daily refractivity in the Coastal and Sahel during the rainy seasons are 339-390 and 311-384 N-units respectively. Analysis of the results obtained indicates that the annual mean of the ITU-R recommendation underestimates surface refractivity by 11-15% across the coastal stations and by 5-10% across the Sahel zone. The derived values for each station would be useful for radio engineers in the design and optimization of terrestrial radio links.
    VL  - 7
    IS  - 1
    ER  - 

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Author Information
  • Department of Physics, University of Africa, Toru-Orua, Nigeria

  • Department of Physical and Chemical Sciences, Elizade University, Ilara-Mokin, Nigeria

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