Tropospheric Variation of Point Refractivity Gradient and Geo-climatic Factor over a Coastal Location in Tropical Nigeria

Year : 2024 | Volume :15 | Issue : 02 | Page : 29-43
By

Okikiade Adewale Layioye,

  1. Student Department of Physics, Federal University of Technology Akure Nigeria

Abstract

Accurate assessment of refractivity gradient and Geo-climatic factor is crucial for maintaining reliable radio signal propagation in clear-air environments. These parameters are essential for determining the fade margin necessary to ensure a stable and effective wireless radio link, given the unstable nature of the atmosphere through which the signals travel. It is crucial to have accurate knowledge of these characteristics, particularly at microwave antenna heights of around 70 meters, in order to sustain a functional line-of-sight (LOS) link even in the most adverse weather circumstances. The lack of adequate studies on this topic for Lagos made the investigation necessary. This study utilized meteorological data, including surface air temperature, dew point temperature, and relative humidity, obtained from the European Centre for Medium-Range Weather Forecasts (ECMWF) archive over a period of six years. The point refractivity gradient at 70 meters and refractive conditions were estimated for Ikeja, Lagos State, which is a coastal city within tropical Nigeria. The study’s findings demonstrate that the Geo-climatic factor and point refractivity gradient in the studied area change with the seasons. Specifically, for Ikeja and its environs, the research found that the average point refractivity gradient and Geo-climatic factor at 70 meters above ground level are -196.30 N-units/km and 1.06E-04, respectively. These findings indicate that radio waves propagating in this region at the specified altitude are likely to experience super refraction under both rainy and clear-air atmospheric conditions. In addition, wet months show high variability of refractivity gradient of about -167.828 N-units/km due to increase in the water vapour in the atmosphere compared to the dry periods with low variability of about -196.296 N-units/km. Also, the average values of the Geo-climatic factor in the wet season are 8.66774E-05 and that of the dry season is 0.000133. This suggests that extremely poor radio propagation condition is expected to take place within the dry months, especially in November. This study highlights the significant influence of meteorological parameters such as temperature, pressure, and humidity on the quality of services provided by inter-terrestrial radio communication links, including GSM networks, Wide Area Networks (WAN), and radio and TV broadcasts. The insights gained from this research are particularly valuable for radio engineers involved in the design and configuration of inter-terrestrial microwave links in Ikeja and its environs, facilitating optimal quality of service even during adverse weather conditions.

Keywords: Geo-climatic factor, radio communication, electromagnetic waves, GSM networks, Wide Area Networks (WAN)

[This article belongs to Journal of Remote Sensing & GIS(jorsg)]

How to cite this article: Okikiade Adewale Layioye. Tropospheric Variation of Point Refractivity Gradient and Geo-climatic Factor over a Coastal Location in Tropical Nigeria. Journal of Remote Sensing & GIS. 2024; 15(02):29-43.
How to cite this URL: Okikiade Adewale Layioye. Tropospheric Variation of Point Refractivity Gradient and Geo-climatic Factor over a Coastal Location in Tropical Nigeria. Journal of Remote Sensing & GIS. 2024; 15(02):29-43. Available from: https://journals.stmjournals.com/jorsg/article=2024/view=167728

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Regular Issue Subscription Original Research
Volume 15
Issue 02
Received June 10, 2024
Accepted July 7, 2024
Published July 10, 2024
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