JETI Admin2
Abstract
This paper titled “Impact of Tropospheric Meteorological Constituents on Microwave
Signal in Ekiti State, South West, Nigeria”, assesses the impact of radio refractivity over Ekiti State Nigeria using meteorological variables of atmospheric temperature, pressure, water vapour and relative humidity downloaded from the archive of ERA-5, a climate reanalysis produced by European Center for Medium-Range Weather Forecast (ECMWF) at four synopsis hours; 00:00 hours, 06:00 hours, 12:00 hours and 18:00 hours at 2m and 100m for each research locations daily for five years (2017-2021) on regular latitude-longitude grids at 0.25° × 0.25° resolutions. The daily and monthly averages of the meteorological variables were used to evaluate the daily and seasonal values of radio refractivity, the influence of the parameters on radio refractivity and the gradients of modified radio refractivity of the locations. The results obtained indicate that radio refractivity varies on daily and seasonal bases with higher values occurring during the wet season months and radio refractivity decreases with height. The results further reveal a strong correlation between atmospheric temperature and refractivity and relative humidity and radio refractivity with a negative and positive correlation respectively. There was strong positive correlation between atmospheric pressure and radio refractivity at 2m height while at 100m; there was little or no correlation between pressure and refractivity.
References
[1] Er. Dhiman, R. “Microwave and Radar Engineering,” New Delhi: S.K. kataria & Sons, 2014. [2] Enyenihi, H. J, Simeon, O and Kalu, C. “Development of Model for Estimation of Radio Refractivity from Meteorological Parameters over Cross River, Nigeria,” Universal Journal of Engineering Science, 2019; 7:20-26. [3] Yusuf, Y., Adetan, O., and Adewale, A.S., “Effects of Tropospheric Variables on Radio Signal Propagation in Tropical Climate,” International Conference of Engineering and Earth Science (ICEES), held at Federal Polytechnic, Ado-Ekiti from 31st July to 3rd August, 2023. [4] Otasowie P. O and Edeko F. O., “Radio Refractivity Study in Akure-Owo Digital Microwave Link in South Western Nigeria,” Nigerian Journal of Technology, 2015; 34: 606 – 608. [5] Chima A.I., Chizea, F.D., Ayantunji, B.G and Kassimu, A.A., “The Comparative study of the impact of refractivity in Enugu South Eastern Nigeria: a case study of Enugu State University of Science and Technology,” IOSR Journal of Applied Physics, 2019; 11: 16-23. [6] Adediji, A. T., “Reduced-To-Sea- Level Value of Microwave Radio Refractivity Over three Stations In Nigeria,”. Nigeria Journal of Pure and Applied Physics, 2017; 7:19–25. [7] Recommendation ITU-R P.453-11., “The radio refractive index: its formula and refractive Data,” Retrieved 04 September 2020 from https://www.itu.int, 2015. [8] Yusuf Y, Aboloma, C.A and Oloke, O.R., “Monthly Average Estimation of Radio Refractivity of Ado-Ekiti, South-Western Nigeria. Journal of Engineering and Earth Sciences”, 2022; 15:1-8. [9] Saleem, M. U., “Statistical Investigation and Mapping of Monthly Modified Refractivity Gradient Over Pakistan at the 700 Hectopascal Level,” Open Journal of Antennas and Propagation. http//dx.doi.org/10.4236/ojapr.2016.42005, 2016; 4:46-63. [10] Akeem, L. S., Kamaldeen, O. S., & Qassim, A. A, Investigation of the vertical profile radio refractivity gradient and effective earth radius factor in transmission line over Oyo, Oyo state south western Nigeria. Tanzania Journal of Science, 2022; 48:134 – 139. [11] Mmahi, N. O., Akinbolati, A., Nkechiamaka, F. N., Akpaneno, A. F., Joseph, E., and Ekunadayo, K. R., “Studies on surface radio refractivity over some selected cities in North - Central Nigeria,” FUDMA Journal of sciences, 2021; 5:90 – 99. [12] Abimbola, O. J., Bada, S. O., Falaiye, A. O., Sukam, Y. M., Otto, M. S., and Muhammad, S., “Estimation of radio refractivity from satellite-derived meteorological data over a decade from West Africa, ” Scientific African, 2020; 14:1-8. [13] Falodun, S.E, Ojo, J. S. and Oviangbede, V. O., “Spatial and Temporal Distribution of Modified Radio Refractivity Gradient at 875 hPa and 700 hPa over Nigeria,” International Journal of Physical Science, 2019; 23:1-13. [14] Khurram S.Alimgeer, Muhammad Awais, BilalIjaz, Shahid A.Khan, Fazli Subhan, and Naveed Ahmad., “Statistical Estimation and Mathematical Modelling of Tropospheric Radio Refractivity Based on Meteorological Data,” Metrological and Measurement Systems, 2018; 25:115–128. [15] Abdullahi, S. A, “Experimental Determination of Three Hourly Refractivity of Idah, Kogi State, Nigeria,”International Journal of Science and Research, 2017; 6: 459-463. [16] Bawa, M, Ayantunji, B.G, Mai- Unguwa, H, Galadanchi G.S, and Shamsuddeen I.M., “Study of average hourly variations of radio refractivity variation across some selected coastal cities in Nigeria,” IOSR journal of applied physics. 2015; 7: 37-43. [17] Amajama, J., “Impact of weather components on (UHF) Radio Signal,” international Journal of Engineering Research and General Science, 2016; 4:481-494. [18] Adediji, A.T., and Ajewole, M.O., “Vertical Profile of Radio Refractivity Gradient in Akure South-West Nigeria, ” Progress In Electromagnetics Research C, 2008; 4:157–168. [19] Akpootu D.O and Iliyasu, M.I., “Estimation of tropospheric radio refractivity and its variation with meteorological parameters over Ikeja, Nigeria,” Journal of geography environment and Earth science international, 2016; 10: 1- 12. [20] Falodun, S.E and Ajewole, M.O., “Radio Refractivity index in the lowest 100m layer of the troposphere in Akure, South Western Nigeria,” Journal of Atmospheric and solar-terrestrial Physics, 2006; 68: 236-243.