Authors : Ishiyaku Ibrahim Babayo; Ahmadu Muhammad Aliyu; Hamza Abubakar Hamza; Aliyu Sisa Aminu; Usman Muhammad Bakura; Yohanna Herbert

Volume/Issue : Volume 11 - 2026, Issue 4 - April

Google Scholar : https://tinyurl.com/m7fkfaam

Scribd : https://tinyurl.com/6658r8ve

DOI : https://doi.org/10.38124/ijisrt/26apr2379

Note : A published paper may take 4-5 working days from the publication date to appear in PlumX Metrics, Semantic Scholar, and ResearchGate.

Abstract : Atmospheric conditions play a critical role in radio wave propagation through mechanisms such as refraction, reflection, and scattering. This study examines the seasonal variability of atmospheric radio refractivity over Gombe, Northeastern Nigeria, using meteorological data obtained from the Nigerian Meteorological Agency (NiMET) for the period 2021–2022. Surface parameters, including temperature, atmospheric pressure, relative humidity, and water vapour pressure, were utilized to compute radio refractivity, refractivity gradient, and the effective Earth radius factor (k-factor). The results indicate a pronounced seasonal dependence of refractivity, with elevated values observed during the wet season due to increased atmospheric moisture content. The refractivity gradient reached minimum values of −49 N-units/km in 2021 and −47 N-units/km in 2022 during the rainy season, while maximum values of −37 N-units/km and −35 N-units/km were recorded for the respective years. The mean refractivity gradient for both years is lower than the standard atmospheric value of −40 N-units/km, suggesting enhanced refractive conditions. Furthermore, the mean k-factor values of 1.38 (2021) and 1.39 (2022) exceed the standard value of 1.33, indicating the dominance of super-refractive conditions over the study area. These atmospheric conditions imply increased downward bending of radio waves compared to the standard atmosphere, which may adversely impact radar performance and terrestrial microwave communication links. The findings provide valuable insights for the planning, design, and optimization of reliable radio communication systems in the region.

Keywords : Atmospheric Refractivity, Tropospheric Propagation, Seasonal Variation, Refractivity Gradient.

References :

1. Agbo, G.A., Onuorah, L.O., Okoh D., (2020). Daily and Seasonal Variations of Tropospheric Radio Refractivity at Akure in South- Western Nigeria using Campbell Scientific Automatic Weather Instrument. International Research Journal of Innovations and Engineering and technology, Volume 4, Issue 2 Pp 1-7 ISSN (O): 258-3048      
2. Akpootu, D. O., Aminu, Z., Yusuf, A., Nouhou, I., Kola, T. A., Agidi, O. E., Salifu, S. I., Idris, M., & Aliyu, M. A. (2024). Investigation of tropospheric radio refractivity and other relevant parameters using meteorological variables over Bauchi, Nigeria. FUDMA Journal  of Sciences, Volume 8, Issue 2, Pp306–314. ISSN (Print): 2616-1370; ISSN (Online): 2645-2944
3. Akpootu, D. O. & Iliyasu, M. I. (2017). Estimation of tropospheric radio refractivity and its variation with meteorological parameters over Ikeja, Nigeria. Journal of Geography, Environment and Earth Science International,  Pp 1–12 ISSN: 2454-7352
4. Bean and Dutton (1966). Radio Meteorology. NBS Monograph 92. U.S. Department of Commerce, National Bureau of Statistics. ISBN-13: 978-0-486-62063-3(Dover reprint) ISBN-10: 0-486-62063-9
5. International Telecommunication Union (2016). Recommendation ITU-R P.453: The radio refractive index: its formula and refractivity data. Geneva, Switzerland.
6. John T. Kraus (1988). Antennas (2nd ed.). McGraw-Hill, New York. Pp 12-18. ISBN-13: 978-0-07-035422-7  ISBN-10: 0-07-035422-7
7. Korak, SP.N. (2003).The Physics of the Earth and its Atmosphere. John Wiley and Sons Inc. Newyork, USA, Pp12-18
8. Leslie W. Barclay (2003). Propagation of Radiowaves (2nd ed.). Institution of Engineering and Technology (IET), London.
9. Louis J. Ippolito (2008). Satellite Communications Systems Engineering:  Atmospheric Effects, Satellit Link Design and System Performance.  Wiley 1st ed. ISBN: 9780470725276.
10. Otason, P.O.and Edekon, F.O.  (2015). Radio Refractivity Study in Akure-Owo Digital Microwave Link in South Western Nigeria. Nigerian Journal of Technology (NIJOTECH), Volume 34, Issue 3 Pp. 606-608. ISSN: 1115-8443(print), eISSN: 2467-8821 DOI: //doi.org/10.4314/njt.343.982
11. Robert Hall (1979). Electromagnetic Fields and Waves. McGraw-Hill. ISBN: 0:471-58551-3
12. Tanko, M. M., Sarki, M. U., & Bilya, M. A. (2019). Seasonal Variation of Radio Refractivity of  Some Selected Stations in Northern Nigeria. Current Journal of Applied Science and Technology, Volume 32 Issue 1, Pp1–12. ISSN: 2457-1024
13. World Meteorological Organization (2018). Guide to Meteorological Instruments and Methods of Observation (WMO-No. 8). Geneva, Switzerland.