volume | PIER Journals

2008-09-17

Vertical Profile of Radio Refractivity Gradient in Akure South-West Nigeria.

Adekunle Titus Adediji,

Dr. Adekunle Titus Adediji

Department of Physics

Federal University of Technology, Akure

Nigera

Homepage

Moses Ajewole

Prof. Moses Ajewole

Department of Physics

Federal University of Technology Akure

Nigera

Homepage

Progress In Electromagnetics Research C, Vol. 4, 157-168, 2008

doi:10.2528/PIERC08082104 | Google Scholar

Abstract

In the planning and design of microwave communication links, the structure of the radio refractive index in the lower part of the atmospheric boundary layer is very important. In this work, measurements of atmospheric pressure, temperature and relative humidity were made in Akure (7.15^oN, 5.12^oE), South Western Nigeria. Wireless weather stations (Integrated Sensor Suite, ISS) were positioned at five different height levels beginning from the ground surface and at intervals of 50m from the ground to a height of 200m (0, 50, 100, 150 and 200 m) on a 220m Nigeria Television Authority TV tower at Iju in Akure North Local Government area of Ondo State. The measurement of the atmospheric variables was made every 30 minutes everyday. The study utilized the data for the first year of measurement (January-December 2007) to compute the radio refractivity and its refractivity gradient in Akure. From these parameters, the vertical distributions of radio refractivity are then determined. The results obtained show that the propagation conditions have varying degree of occurrence with sub-refractive conditions observed to be prevalent between January-July while Super-refraction and Ducting were observed mostly between August-December.

Download Full Article (337) View Full Article volume

Citation

Copy Export

Adekunle Titus Adediji, and Moses Ajewole, "Vertical Profile of Radio Refractivity Gradient in Akure South-West Nigeria.," Progress In Electromagnetics Research C, Vol. 4, 157-168, 2008.
doi:10.2528/PIERC08082104

References

1. Babin, S. M., G. S. Young, and J. A. Carton, "A new model of the oceanic evaporation duct," Journal of Applied Meteorology, Vol. 36, 193-204, 1997.
doi:10.1175/1520-0450(1997)036<0193:ANMOTO>2.0.CO;2 Google Scholar

2. Falodun, S. E. and L. B. Kolawole, "Studies of super-refractivity and ducting of radiowaves in Nigeria," Nigeria journal of Pure and Applied Physics, Vol. 1, 5-10, 2000. Google Scholar

3. Falodun, S. E. and M. O. Ajewole, "Radio refractive index in the lowest 100m layer of the troposphere in Akure, South Western Nigeria," Journal of Atmospheric and Solar-Terrestrial Physics, Vol. 68, 236-243, 2006.
doi:10.1016/j.jastp.2005.10.002 Google Scholar

4. Grabner, M. and V. Kvicera, "Clear-air propagation modelling using parabolic equation method," Radio Engineering, Vol. 12, No. 4, 50-54, 2003. Google Scholar

5. Hajj, G. A., E. R. Kursinski, L. J. Romans, W. I. Bertiger, and S. S. Leroy, "A technical description of atmospheric sounding by GPS occultation," Journal of Atmospheric and Solar-Terrestrial Physics, Vol. 64, 451-469, 2002.
doi:10.1016/S1364-6826(01)00114-6 Google Scholar

6. ITU-R The Refractive Index: Its Formula and Refractivity Data, 453-9, 2003.

7. Kolawole, L. B., "Statistics of radio refractivity and atmospheric attenuation in tropical climates," Proceedings of the URSI Commission F Symposium, 69-75, Belgium, 1983. Google Scholar

8. Lowry, A. R., C. Rocken, and S. V. Sokolovskiy, "Vertical profiling of atmospheric refractivity from ground-based GPS," Radio Science, Vol. 37, No. 3, 13-1-13-10, 2002.
doi:10.1029/2000RS002565 Google Scholar

9. Oyinloye, J. O., "The troposphere in tropical and sub-tropical latitudes," Handbook on Radio Propagation for Tropical and Sub-Tropical Countries, 77-79, URSI Committee on Developing Countries, 1987. Google Scholar

10. Willoughby, A. A., T. O. Aro, and I. E. Owolabi, "Seasonal variations of radio refractivity gradients in Nigeria," Journal of Atmospheric and Solar-Terrestrial Physics, Vol. 64, 417-425, 2002.
doi:10.1016/S1364-6826(01)00111-0 Google Scholar