Onuorah, Loretta O. and Agbo, Godwin A. and Okoh, Daniel I. and Najib, Yusuf and Ibeh, Gabriel F. (2022) Tropospheric radio refractivity trends over vegetation regions in Nigeria. In: Meteorology and Atmospheric Physics. UNSPECIFIED, pp. 1-12.
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Abstract
Refractivity is an important parameter in understanding radio wave propagation in the troposphere. We investigated both the monthly variations of refractivity and its trends over vegetation regions in Nigeria. Application of Matlab program was used to compute the values of radio refractivity from meteorological variables for a period 1979–2013, using ITU-R P 453-12 (The radio refractivity index; its formula and refractivity data. Recommendations and reports Geneva Switzerland, 2016) model. Results show that the pattern of radio refractivity variation at various locations in Nigeria is not the same due to the diferent vegetation regions. The states within the Freshwater and Rainforest regions were found to have higher refractivity values than those in the Guinea savannah, Sudan savannah and Sahel savannah regions in Nigeria. The Guinea savannah region of Nigeria (called the middle belt) has the same trend with the other parts of savannah regions in Nigeria. The only diference found is in the refractivity values. The mean refractivity values revealed that the Guinea and Sahel savannah regions have higher refractivity values than Sudan savannah region while, the Sahel savannah region has lower refractivity values than Guinea savannah region. The trends of refractivity show that refractivity increases by 0.1 N units per year in the Freshwater and Rainforest regions and decreases by 0.1 N units per year in the savannah regions of Nigeria. The average monthly value of refractivity increases from a value of approximately 356 N units in Sudan savannah region to maximum value of approximately 382 N units in Freshwater region. This indicates that the radio refractivity value increases from the savannah region to the Freshwater region of Nigeria. It was also observed that the Guinea savannah region radio refractivity values were lower than those of the Freshwater and Rainforest regions, but greater than those of the Sudan and Sahel regions. This observation is coherent with the knowledge that the Rainforests (south of the Nigeria) are more humid than the dry climates (north of the Nigeria), and so the Rainforests have greater refractivity values than the Sudan and Sahel regions. The Guinea savannah which is geographically located between these two sets of regions has moderate refractivity values.
| Item Type: | Book Section |
|---|---|
| Subjects: | Q Science > Q Science (General) |
| Divisions: | Faculty of Natural and Applied Sciences |
| Depositing User: | mrs chioma hannah |
| Date Deposited: | 23 Aug 2022 10:47 |
| Last Modified: | 23 Aug 2022 10:47 |
| URI: | http://eprints.gouni.edu.ng/id/eprint/3613 |
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