Determination of rain attenuation from electromagnetic scattering by spherical raindrops: Theory and experiment

Odedina, Modupe Olubunmi.; Afullo, Thomas J.

doi:10.1029/2009rs004192

Cited by 27 publications

(23 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The kth moment for an arbitrary N (D), can be obtained from [3,10]: (19) If N (D) is the lognormal distribution defined in (8), then, using the third, fourth, and sixth moments (M 3 , M 4 , and M 6 ), the lognormal parameters N T , µ and σ 2 can be estimated as [25]:…”

Section: Methods Of Moments For Raindrop Size Distributionmentioning

confidence: 99%

“…On the other hand, the Indian and Nigerian models consistently underestimate rain attenuation in Durban by 2-8 dB/km for frequencies above 10 GHz. In Figure 5(b), the two Durban and two ITU-R models' attenuation coefficients are compared at 20 GHz, for rain rates varying from 1-80 mm/hr, against measurements done over a 6.73-km line-of-sight link operating at 19.5 GHz in Durban, as reported by [9,19].…”

Section: Comparisons Of Specific Attenuation Valuesmentioning

confidence: 99%

“…[19] derived the constants κ and ζ at 20 • C, for the frequency range 1-35 GHz, with Q ext in cm 2 . We have used slightly modified values of these parameters, also at 20 • C, with Q ext in mm 2 , in order to determine the specific attenuation through Equation (2).…”

Section: Comparisons Of Specific Attenuation Valuesmentioning

confidence: 99%

“…Mulangu and Afullo [18] used the Mie scattering approach and the dielectric model of Liebe to determine the extinction coefficients in (2) and, thus, the specific rain attenuation for Botswana, over the frequency range of 1-1000 GHz. Odedina and Afullo [19] determined the forward scattering amplitudes for spherical raindrops at different frequencies by using the MarshallPalmer DSD [16], the lognormal DSD [1,3], and the Weibull DSD [22]. However, to the author's knowledge, there has been no reported estimate of N (D) for South Africa.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Raindrop Size Distribution Modeling for Radio Link Design Along the Eastern Coast of South Africa

Afullo¹

2011

PIER B

View full text Add to dashboard Cite

Abstract-A study of the raindrop size distribution along the eastern coast of South Africa (Durban) is presented. The Biweight kernel estimator based on distometer measurement is used to determine the best estimate of the measured raindrop size probability distribution function (pdf). The best kernel estimator, which results in the lowest integral square error (ISE), is used to measure the closeness of the estimated lognormal and gamma pdf of raindrop size to the measured raindrop size distribution. It is established that the optimised lognormal pdf slightly outperforms the optimised gamma pdf in terms of the mean ISE and the RMSE values, with mean ISE values of 0.026 for lognormal and 0.04 for gamma distributions, respectively, and corresponding mean RMSE values of 0.073 and 0.081, respectively. The method-of-moments gamma and lognormal distributions are observed to be worse estimators of the measured pdf than the two optimized distributions. The N (D) distributions using the optimised lognormal and gamma distributions for the region are compared with those for different tropical regions, namely, India, Singapore, Nigeria, Indonesia, and Brazil. While the Indian lognormal N (D) model gives the highest peak for low raindrop sizes for all rain rates, Durban's gamma and lognormal models exhibit the widest raindrop size spread over all rain rates ranging from 1-120 mm/h. Finally, the specific attenuation due to rain using the Durban models are compared against the ITU-R models and actual measurements over a 19.5 GHz LOS link; the results indicate a need for further work involving both distrometer and radio link measurements for rain rates exceeding 30 mm/h in the eastern coast of South Africa.

show abstract

Section: Methods Of Moments For Raindrop Size Distributionmentioning

confidence: 99%

Section: Comparisons Of Specific Attenuation Valuesmentioning

confidence: 99%

Section: Comparisons Of Specific Attenuation Valuesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Raindrop Size Distribution Modeling for Radio Link Design Along the Eastern Coast of South Africa

Afullo¹

2011

PIER B

View full text Add to dashboard Cite

show abstract

“…Several works have been done by researchers on rainfall attenuation and raindrop size distribution in the tropical and equatorial regions, as well as in Durban (29 • 52 S, 30 • 58 E), South Africa [7][8][9][10][11][12][13][14][15][16][17]. In 2006, Owolawi [10] estimated the M-P parameters for Durban and defined the intercept parameter (drop density per unit volume), N 0 .…”

Section: Previous Work Done On Rainfall Rate and Dsd Models In Durbanmentioning

confidence: 99%

The Critical Diameters for Rainfall Attenuation in Southern Africa

Afullo¹

2013

PIER B

View full text Add to dashboard Cite

Abstract-This paper investigates the influence of critical raindrop diameters on the specific rain attenuation in Durban (29 • 52 S, 30 • 58 E), South Africa. The total rainfall attenuation is evaluated by integrating over all the raindrop sizes and the differential change in the attenuation is observed over a given range of drop size diameters. The major contribution to the specific attenuation for the drop size distribution (DSD) models considered is created by the raindrop diameters not exceeding 2 mm especially at higher frequencies. The three parameter lognormal and gamma distribution models are employed for the purpose of analysis. For the DSD models considered in this work, the total percentage fraction created by raindrops in the diameter range 0.5 mm ≤ D ≤ 2.5 mm and 1 mm ≤ D ≤ 3 mm to the total specific attenuation is found to be critical for the overall and seasonal rainfall attenuation at 2.5 GHz-100 GHz in Durban. It is observed that the total specific attenuation increases with increased frequencies and a higher rainfall rate produces high rain attenuation. In this paper, both the overall and seasonal values of R 0.01 determined for Durban are used.

show abstract

Specific Rain Attenuation Derived from a Gaussian Mixture Model for Rainfall Drop Size Distribution

Ekerete

Hunt

Jeffery

et al. 2017

Wireless and Satellite Systems

View full text Add to dashboard Cite

Determination of rain attenuation from electromagnetic scattering by spherical raindrops: Theory and experiment

Cited by 27 publications

References 36 publications

Raindrop Size Distribution Modeling for Radio Link Design Along the Eastern Coast of South Africa

Raindrop Size Distribution Modeling for Radio Link Design Along the Eastern Coast of South Africa

The Critical Diameters for Rainfall Attenuation in Southern Africa

Specific Rain Attenuation Derived from a Gaussian Mixture Model for Rainfall Drop Size Distribution

Contact Info

Product

Resources

About