Estimation of Tropospheric Radio Refractivity and Its Variation with Meteorological Parameters over Ikeja, Nigeria

Akpootu, D. O.; Iliyasu, Mukhtar Isah

doi:10.9734/jgeesi/2017/32534

Cited by 14 publications

(27 citation statements)

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“…The part of the atmosphere most closely related to human life is the troposphere [7]. It is the lowest layer of earth's atmosphere and region of all weather on earth [7].…”

Section: Introductionmentioning

confidence: 99%

“…The part of the atmosphere most closely related to human life is the troposphere [7]. It is the lowest layer of earth's atmosphere and region of all weather on earth [7]. The troposphere extends from the earth's surface to an altitude of about 10 km at the earth's poles and 17 km at the equator and tends to affect radio frequencies above 30 MHz [8].…”

Section: Introductionmentioning

confidence: 99%

“…Refractive index is not constant in the atmosphere and its space-time distribution results in scattering, sub-refraction, super-refraction, ducting and absorption phenomena [13]. The variation of refractive index as well as specific attenuation of micro/radio wave may be estimated indirectly with the measurement of temperature, pressure and relative humidity [7].…”

Section: Introductionmentioning

confidence: 99%

“…How far a radio signal will travel within the radio horizon is determined by the distribution of the radio refractivity [1]. Several researchers like [1], [7] and [14 -19] have carried out studies on radio refractivity for different regions and climates using measured local meteorological data in Nigeria and other parts of the world. The results of their study showed that the local climate has a substantial influence on the radio refractivity and consequently on the transmitted radio signals.…”

Section: Introductionmentioning

confidence: 99%

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Performance Analysis of Tropospheric Radio Refractivity on Radio Field Strength and Radio Horizon Distance and Its Variation with Meteorological Parameters over Osogbo, Nigeria

Akpootu

Sa’id

Mustapha

et al. 2019

IJASRE

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Radio refractivity estimation is paramount in the planning and design of radio link/systems for the purpose of achieving optimal performances. In this study, the monthly average daily atmospheric pressure, relative humidity and temperature data obtained from the National Aeronautics and Space Administration (NASA) during the period of twenty two years (July 1983 -June 2005 for Osogbo (Latitude 7.47 0 N, Longitude 4.29 0 E, and 302.0 m above sea level) were used to estimate the monthly tropospheric radio refractivity and to investigate its variation with other meteorological parameters of monthly average daily atmospheric pressure, relative humidity, absolute temperature, saturation vapour pressure and radio refractive index. The field strength variability (FSV) and the radio horizon distance were also computed. The monthly variation of FSV using two years data (2003 -2004) was also investigated. The results of this study revealed that the values of radio refractivity are more during the rainy season than in the dry season. It was found that the maximum average value of tropospheric radio refractivity of 370.98 N-units and minimum average value of 332.36 N-units occurred in the months of May and January during the rainy and dry seasons respectively. 71.45 % of the total value of the radio refractivity was contributed by the dry term while the major variation is by the wet term radio refractivity. The average refractivity gradient computed for the study area under investigation was −42.69 Nunits/km and the average effective earth radius (kfactor) was 1.37 which corresponds to the conditions of super refraction. The annual maximum mean value of FSV is 7.72 dB and minimum monthly mean value of 0.07 dB was obtained for the study area. The implication of this FSV values is that the output of a receiving antenna in Osogbo may generally be subjected to changes not less than 0.07 dB in a year and not greater than 7.72 dB. The descriptive statistical analysis shows that the radio refractivity, relative humidity, absolute temperature and radio refractive index data spread out more to the left of their mean value (negatively skewed), while the atmospheric pressure data spread out more to the right of their mean value (positively skewed). The radio refractivity, relative humidity and radio refractive index data have positive kurtosis which indicates a relatively peaked distribution and possibility of a leptokurtic distribution. The atmospheric pressure and absolute temperature data have negative kurtosis which indicates a relatively flat distribution and possibility of platykurtic distribution.

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“…The part of the atmosphere most closely related to human life is the troposphere [7]. It is the lowest layer of earth's atmosphere and region of all weather on earth [7].…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Performance Analysis of Tropospheric Radio Refractivity on Radio Field Strength and Radio Horizon Distance and Its Variation with Meteorological Parameters over Osogbo, Nigeria

Akpootu

Sa’id

Mustapha

et al. 2019

IJASRE

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“…Radio waves are significantly affected by the atmospheric conditions; particularly, the radio waves can be reflected, refracted, absorbed or scattered in the atmosphere [3,9,10]. Among these effects, atmospheric refraction or bending of the radio signal path occurs due to variations of primary radioclimatic parameter, namely temperature, pressure and relative humidity [11,12,13,14]. Therefore, the extent to which the radio wave path will be bent in the atmosphere is called refractivity [11,14,15,16].…”

Section: Introductionmentioning

confidence: 99%

Development of Model for Estimation of Radio Refractivity from Meteorological Parameters

Johnson¹,

Ozuomba²,

Kalu³

2019

ujes

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In this paper development and validation of a simple linear model for estimating radio refractivity from meteorological parameters are presented. Twelve months radiosonde meteorological data for Cross River state which was obtained from Nigerian Meteorological Agency (NIMET) was used to determine the radio refractivity (N). The correlation between the refractivity and the atmospheric temperature (T), atmospheric pressure (P) and relative humidity (U) were examined for twelve months dataset. The correlation values showed that temperature (T) and the product of P, H and T had the highest correlation with respect to N in all the twelve months. Based on the correlation values among the parameters examined, a simple linear model was developed to estimate the radio refractivity. In all the twelve months dataset, the mathematical model gave worst case absolute percentage error of about 3.3%. Two sample meteorological dataset from published articles were also used to validate the model. The model gave a maximum absolute percentage error of 2.46 % for the first test meteorological dataset while it gave a maximum absolute percentage error of 1.25 % for the second test meteorological dataset. In all, the linear model presented in this paper will make it easier to compute the radio refractivity from available meteorological data. The results from the validation dataset showed that the model can also be applied to every other region other than the case study area where the data for the model development were obtained.

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Analysis of the effects of meteorological parameters on radio refractivity, equivalent potential temperature and field strength via Mann-Kendall test

Agbo

Ekpo

Edet

2021

Theor Appl Climatol

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Trend analysis of meteorological parameters (temperature, pressure, and relative humidity) as well as calculated refractivity, equivalent potential temperature (EPT) for a pseudo-adiabatic process, and field strength in Calabar, Southern Nigeria has been analyzed using Mann-Kendall trend test and Sen's slope estimator. Data of the meteorological parameters were obtained from the Nigerian Meteorological Agency (NiMet) in Calabar for 14 years (2005 -2018). Results show that the maximum and average temperature, atmospheric pressure, refractivity, EPT and field strength all exhibited a positive Kendall Z value with 2.52, 0.33, 3.83, 0.77, 0.44 and 3.18 respectively which indicated an increasing trend over time, with only maximum temperature, atmospheric pressure and field strength showing a significant increase at 5% (0.05) level of significance, since their calculated p-values (0.012, 0.0001, and 0.001) were less than 0.05. The relative humidity and minimum ambient temperature showed a decrease in trend over time as they both had a negative Kendall Z values (-0.11 and -1.09 respectively), however, together with the average ambient temperature and refractivity, their trend wasn't significant 5% level of significance since their calculated p-values were all more than 0.05. Linear regression, correlation and partial differentiation showed that relative humidity has the most effect on the changes in seasonal refractivity and an indirect relationship with field strength variability. The relationship between EPT and refractivity has been discovered to be very strong and positive. Descriptive statistics has been used to portray the seasonal and annual trend of all parameters.

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Estimation of Tropospheric Radio Refractivity and Its Variation with Meteorological Parameters over Ikeja, Nigeria

Cited by 14 publications

References 0 publications

Performance Analysis of Tropospheric Radio Refractivity on Radio Field Strength and Radio Horizon Distance and Its Variation with Meteorological Parameters over Osogbo, Nigeria

Performance Analysis of Tropospheric Radio Refractivity on Radio Field Strength and Radio Horizon Distance and Its Variation with Meteorological Parameters over Osogbo, Nigeria

Development of Model for Estimation of Radio Refractivity from Meteorological Parameters

Analysis of the effects of meteorological parameters on radio refractivity, equivalent potential temperature and field strength via Mann-Kendall test

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