Tropical Rain Intensity Impact on Raindrop Diameter and Specific Signal Attenuation at Microwaves Communication Link

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Isabona Joseph 1,* Ibrahim Habibat Ojochogwu 2 Ituabhor Odesanya 1

1. Department of Physics, Federal University Lokoja, PMB 1154, Kogi State, Nigeria

2. Salem Salem University Lokoja, Km 16 Lokoja-Ajaokuta Rd, 263106, Kogi State, Nigeria

* Corresponding author.


Received: 27 Jun. 2022 / Revised: 27 Aug. 2022 / Accepted: 13 Jan. 2023 / Published: 8 Apr. 2023

Index Terms

Lognormal model, Weilbull model, Rain rate, Rain attenuation, Raindrop concentration, Raindrop diameter, Specific attenuation


Realistic knowledge of rainfall characteristics and modeling parameters such as size, shape, and drop size distribution is essential in numerous areas of scientific, engineering, industrial and technological applications. Some key application areas include, but not limited to microphysics analysis of precipitation composition phenomenon, weather prediction, signal attenuations forecasting, signal processing, remote sensing, radar meteorology, stormwater management and cloud photo detection. In this contribution, the influence of rain intensity on raindrop diameter and specific attenuation in Lokoja, a typical climate region of Nigeria is investigated and reported. Three different rain rates classes obtained due to heavy rainfall depth, heavy rainfall depth, and heavy rainfall depth have been explored for the raindrop size distribution analysis. The three-parameter lognormal and Weibull models were utilised to estimate the influence of rain rates on the drop sizes and specific rainfall attenuation in the study location. For Lognormal model, the maximum raindrop concentration occurred approximately at diameter of 1 mm before showing downfall performance trends as the drop diameter increases. In the case of Weilbull model, the maximum raindrop concentration occurred at different drop diameter with the three rain rate classes, before showing downfall concentration trends with increasing rain drop diameter values. By means of the two models, the highest raindrops concentration values attained in correspondence with the specific rain attenuation were made by drop diameters not more than 2.5 mm. In terms of rain rate, specific attenuation and frequency connection, the results disclose that attenuation of propagated electromagnetic waves increases at increasing rainfall depth and increasing operating frequency bands. The results also disclose that the specific attenuation is directly proportional to the increase in rain intensity levels in correspondent with the operational frequency. As a case in point, at 4GHz frequency, the attenuation level of about 20 dB/km level is attained for mean, minimum and maximum rain rates of 29.12, 12.23 and 50.22 mm/hr, respectively. But as the frequency increased from 4GHz to 20GHz, the attenuation level almost doubles from 20 to 45dB/km at still same rain rates. The above performance is so, because at higher radio-microwave frequencies, the wavelength of the propagated electromagnetic waves approaches the mean diameter of the raindrop. The results display gradual increase in attenuation levels as the diameter rain drop sizes and intensity increases or become broader. The attenuation grows because the raindrops interfere, distort, absorb and scatter major portion of the microwave energy. However, the gradual trend in the attenuation level increase becomes slower and tending to logarithm stability at larger rain drop values. This may suggest that the attenuation level may come to equilibrium state at higher rain drop diameters. The resultant outcome of this work can assist microwaves communication engineers and relevant stakeholders in the telecommunication sector with expedient information needed to manage specific attenuation problems over Earth–space links communication channels, particualry during rainy seasons.

Cite This Paper

Isabona Joseph, Ibrahim Habibat Ojochogwu, Ituabhor Odesanya, "Tropical Rain Intensity Impact on Raindrop Diameter and Specific Signal Attenuation at Microwaves Communication Link", International Journal of Image, Graphics and Signal Processing(IJIGSP), Vol.15, No.2, pp. 59-72, 2023. DOI:10.5815/ijigsp.2023.02.06


[1]Ekpenyong, M., Umoren. E., & Isabona, J. (009). A Rain Attenuation Model for Predicting Fading Effect on Wireless Communication Systems in the Tropics,” Niger. J. Sp. Res., 6, 21–32.
[2]Linga, P., Iddi, H., & Kissaka, M. (2020). Contour Mapping for Rain Rate and Rain Attenuation in Microwave and Millimetre Wave Earth-Satellite Link Design in Tropical Tanzania,” Tanzania J. Sci., 46, (3), 886–902.
[3]Ebhota, V. C., Isabona, J & Srivastava, V. M. (2019). Environment-Adaptation Based Hybrid Neural Network Predictor for Signal Propagation Loss Prediction in Cluttered and Open Urban Microcells,” Wirel. Pers. Commun., 104 (3), 935–948. doi: 10.1007/s11277-018-6061-2.
[4]Isabona, J.; Imoize, A.L.; Ojo, S.; Lee, C.-C.; Li, C.-T. Atmospheric Propagation Modelling for Terrestrial Radio Frequency Communication Links in a Tropical Wet and Dry Savanna Climate. Information 2022, 13, 141.
[5]Isabona.J & Imoize, A.L. (2021). Terrain-based adaption of propagation model loss parameters using non-linear square regression, J. Eng. Appl. Sci., 68 (33).
[6]J. Isabona, and S. Azi, Measurement, Modeling and Analysis of Received Signal Strength at 800MHz and 1900MHz in Antenna Beam Tilt Cellular Mobile Environment, Elixir Comp. Sci. & Engg. 54 (2013) 12300-12303
[7]Isabona. J. (2020). Wavelet Generalized Regression Neural Network Approach for Robust Field Strength Prediction,” Wirel. Pers. Commun., 114, 3635–3653.
[8]Ebhota, V. C., Isabona, J & Srivastava, V. M. (2018). Base line knowledge on propagation modelling and prediction techniques in wireless communication networks, Journal of Engineering and Applied Sciences (JEAS), 13 (4), 235-240.
[9]Moupfouma, F. (1987). Rain induced attenuation prediction model for terrestrial and satellite-earth microwave links,” in Annales des télécommunications, 42, (9), 539–550.
[10]Afahakan, I. E., Udofia, K. M., & Umoren, M. A. (2016). Analysis of Rain Rate and Rain Attenuation for Earth-Space Communication Links over Uyo-Akwa Ibom State,” Niger. J. Technol., 35(1), 137–143.
[11]Hassan, N. U. L., Huang, C., Yuen, C., Ahmad, A., & Zhang, Y. (2020). Dense small satellite networks for modern terrestrial communication systems: Benefits, infrastructure, and technologies,” IEEE Wirel. Commun., 27(5),96–103.
[12]Barclay, L. (2003). Propagation of Radiowaves, Third Edition IET, 1-433.
[13]Rimven, G. R., Paulson, K. S., & Bellerby,T. (2018). Estimating One-Minute Rain Rate Distributions in the Tropics from TRMM Satellite Data, IEEE J. Sel. Top. Appl. Earth Obs. Remote Sens., 11(10), 3660–3667.
[14]Linga, P., Iddi, H., & Kissaka, M. (2020). Contour Mapping for Rain Rate and Rain Attenuation in Microwave and Millimetre Wave Earth-Satellite Link Design in Tropical Tanzania,” Tanzania J. Sci., vol. 46 (3), 886–902.
[15]Abdulrahman, A. Y., Rahman, T. B. A., Rahim, S. K. B. A., & Md. Rafi Ul Islam (2010). A new rain attenuation conversion technique for tropical regions,” Prog. Electromagn. Res., 26, 53–67.
[16]Kestwal, M. C., Joshi, S & Garia, L.S (2014). Prediction of rain attenuation and impact of rain in wave propagation at microwave frequency for tropical region (Uttarakhand, India),” Int. J. Microw. Sci. Technol., vol. 2014,
[17]Haule, P., Iddi, H., & Kissaka, M. (2020). Rain attenuation distribution for satellite microwave links application in Tanzania,” Indones. J. Electr. Eng. Comput. Sci., 17 (2), 982–987.
[18]Marzuki Marzuki, Dea Kurnia Harysandi, Rini Oktaviani, Lisna Meylani, Mutya Vonnisa, Harmadi Harmadi, Hiroyuki Hashiguchi, Toyoshi Shimomai, L. Luini, Sugeng Nugroho, Muzirwan Muzirwan, Nor Azlan Mohd Aris “ITU-R P. 837-6 and ITU-R P. 837-7 performance to estimate indonesian rainfall,” TELKOMNIKA Telecommunication, Computing, Electronics and Control Vol. 18 (5). 2292-2303 DOI:
[19]Bhattacharya, R., Das, R., Guha, R., Barman, S. D., & Bhattacharya, A. B. (2007). Variability of millimetrewave rain attenuation and rain rate prediction: A survey, Indian Journal of Radio & Space Physics, 36, 325-344.
[20]Maitra, A & Chakraborty, S. (2009). Cloud liquid water content and cloud attenuation studies with radiosonde data at a tropical location,” J. Infrared, Millimeter, Terahertz Waves, 30 (4), 367–373.
[21]Adhikari, A., Bhattacharya, A & Maitra, A. (2012). “Rain-induced scintillations and attenuation of Ku-band satellite signals at a tropical location,” IEEE Geosci. Remote Sens. Lett., 9 4), 700–704.
[22]Huang, J., Gong, S & Cai, B. (2011). The frequency scaling ratio factor of rain attenuation in Ka waveband along earth-space path in China,” in 2011 Second International Conference on Mechanic Automation and Control Engineering, 2011, 7831–7833.
[23]Ahuna, M. N., Afullo, T. J. & Alonge, A. A. (2016). 30-second and one-minute rainfall rate modelling and conversion for millimetric wave propagation in South Africa, SAIEE Africa Res. J., 107(1), 17–29.
[24]Owolawi, P. A., Malinga, S. J. & Afullo, T. J. O. (2012). Estimation of terrestrial rain attenuation at microwave and millimeter wave signals in South Africa using the ITU-R model,” PIERS Proceedings, Kuala Lumpur, Malaysia, 2012.
[25]Ojo, J. S. & Owolawi, P. A. (2014). Development of one-minute rain-rate and rain-attenuation contour maps for satellite propagation system planning in a subtropical country: South Africa,” Adv. Sp. Res., 54, no. 8, 1487–1501.
[26]Sumbiri, D., Afullo, T. J. O. & Alonge, A. (2016). “Rain attenuation prediction for terrestrial links at microwave and millimeter bands over Rwanda,” in 2016 Progress in Electromagnetic Research Symposium (PIERS), 4233–4236.
[27]Sumbiri, D., Afullo, T. J. & Alonge, A., “Rainfall zoning and rain attenuation mapping for microwave and millimetric applications in Central Africa,” Int. J. Commun. Anten. Propag, 6(4), 198–210, 2016.
[28]Shrestha, S & Choi, D.Y. (2019). Rain attenuation study over an 18 GHz terrestrial microwave link in South Korea,” Int. J. Antennas Propag., vol. 2019.
[29]Rose, T & Czekala, H. (2009). RPG-RATPRO radiometer operating manual (version 7.70),” Radiom. Phys. GmbH, Meckenheim, Ger. Tech. Rep, 2009.
[30]Grábner, M., Kvicera, V & Kostelecky, J. (2009). Application of Water Vapour Profiling for Gaseous Attenuation Estimation–Radiometer versus Radiosonde Results, 2009.
[31]Ben-Daoud, A., Ben-Daoud, M., MoroČ™anu, G. A., & M’Rabet, S. (2022) The use of low impact development technologies in the attenuation of flood flows in an urban area: Settat city (Morocco) as a case,” Environ. Challenges, 6, p. 100403.
[32]Christofilakis, V.; Tatsis, G.; Chronopoulos, S.K.; Sakkas, A.; Skrivanos, A.G.; Peppas, K.P.; Nistazakis, H.E.; Baldoumas, G.; Kostarakis, P. Earth-to-Earth Microwave Rain Attenuation Measurements: A Survey on the Recent Literature. Symmetry (2020), 12, 1440.
[33]Christofilakis, V, Tatsis, G, Lolis, CJ, et al. A rain estimation model based on microwave signal attenuation measurements in the city of Ioannina, Greece. Meteorol Appl. 2020; 27:e1932.
[34]Papatsoris, A. D, Polimeris, K., & Lazou, A.A. (2008). Development of rain attenuation and rain rate maps for satellite communications system design in Greece,” in 2008 IEEE Antennas and Propagation Society International Symposium, 2008, 1–4.
[35]Laws, J.O., & Parsons, D.A, The relation of raindrop size to Intensity, Trans. Am. Geophys. Union, 1943, 24,452-460.
[36]Isabona, J, Imoize, A.L & Ojo, S Lee, C. Li. C (2022). "Atmospheric Propagation Modelling for Terrestrial Radio Frequency Communication Links in a Tropical Wet and Dry Savanna Climate" Information 13, no. 3: 141.
[37]Isabona, J, Imoize, A.L Rawat, P., Jamal, S.S., Pant, B., Ojo, S & Hinga, S.K (2022). "Realistic Prognostic Modeling of Specific Attenuation due to Rain at Microwave Frequency for Tropical Climate Region", Wireless Communications and Mobile Computing, 2022.
[38]Ulbrich, C. W., & D. Atlas (1984), Assessment of the contribution of differential polarization to improved rainfall measurements, Radio Sci. J., 19(1), 49–57
[39]Marshall, J.S. & W.M. Palmer. (1948). The distribution of raindrops with size. J. Meteorol. 5:165-166.
[40]Adimula, A.I & Ajayi, G.O. (1996). Variation in raindrop size distribution and specific attenuation due to rain in Nigeria,” Ann. Telecom, 51, 1-2, 87–93.
[41]Sekine, M., & G. Lind (1982), Rain attenuation of centimeter, millimeter and submillimeter radio waves, in Proceedings of the 12th European Microwave Conference, 586–589, IEEE, Helsinki, Finland.
[42]Olatunde, A.F & Isaac A (2018). Rainfall characteristics in Lokoja from 1981 to 2015. J Res Dev Arts Soc Sci 2:228–242.
[43]J. Isabona Joseph and D.O. Ojuh. (2021), ‘‘Application of Levenberg-Marguardt Algorithm for Prime Radio Propagation Wave Attenuation Modelling in Typical Urban, Suburban and Rural Terrains, I.J. Intelligent Systems and Applications, 2021, 7, 35-42
[44]D.O . Ojuh, and J. Isabona, (2021), Empirical and Statistical Determination of Optimal Distribution Model for Radio Frequency Mobile Networks Using Realistic Weekly Block Call Rates Indicator, I. J. Mathematical Sciences and Computing, 2021, 3, 12-23.
[45]D.O . Ojuh, and J. Isabona (2021) Field Electromagnetic Strength Variability Measurement and Adaptive Prognostic Approximation with Weighed Least Regression Approach in the Ultra-high Radio Frequency Band, J. Intelligent Systems and Applications, 2021, 4, 14-23
[46]I. Odesanya Joseph Isabona, Jangfa T. zhimwang, and Ikechi Risi, Cascade Forward Neural Networks-based Adaptive Model for Real-time Adaptive Learning of Stochastic Signal Power Datasets, I. J. Computer Network and Information Security, 2022, 3, 63-74 ( DOI: 10.5815/ijcnis.2022.03.05.
[47]J. Isabona, (2019), Maximum likelihood Parameter based Estimation for In-depth Prognosis Investigation of Stochastic Electric Field Strength Data, BIU Journal of Basic and Applied Sciences, vol. 4(1): 127 – 136, 2019.