Study of the seasonal characteristics of rainfall rate in Southwestern Nigeria and its effect on induced attenuation in earth-satellite communications

IF 1.8 4区地球科学 Q3 GEOCHEMISTRY & GEOPHYSICS

Journal of Atmospheric and Solar-Terrestrial Physics Pub Date : 2024-08-14 DOI:10.1016/j.jastp.2024.106331

M.A. Sodunke , J.S. Ojo , Arijit De

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引用次数: 0

Abstract

Tropospheric propagation channel modeling is gaining more attention in the scientific community, especially in the applications of the upcoming high-frequency satellite communication systems. Channel modeling is essential to predict link performance, for example, in the area of Bit-Error-Ratio (BER) in a single-user scenario and in a multi-user scenario, especially in the areas of throughput and latency. This study investigates the seasonal characteristics of rainfall rate and rain-induced attenuation in terms of exceedance and worst-month rain statistics over selected tropical locations in Nigeria. The coefficient of variation (CV) of rain rate has also been analyzed to examine the variability of rainfall rate due to the inhomogeneity nature of the chosen region. The GPM satellite 30-min rain rate data has been used for rain attenuation prediction through a 30-min to 1-min metric conversion model. Validation of rain attenuation was conducted through a two-year (2013–2014) beacon measurement of rain attenuation at 12.275 GHz at the Akure site. The ITU-R 618–13 (2017) rain attenuation model has been modified based on the rain attenuation beacon measurement. The modified ITU-R model has produced a least root mean square error (RMSE) of 6.4 when compared to the ITU-R model with 23.5 RMSE. The attenuation difference reduces as the frequency difference moves to the upper frequency bands. The ITU-R model overestimates the calculations from the GPM-derived results, which indicates the modification of the ITU-R model for the tropical location. Spatial variation of attenuation at 30 GHz revealed intensive and dry seasons exhibited the highest and lowest attenuation induced values, respectively. The results can be applied to power-enhanced satellite systems to achieve good signal availability in the study areas.

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研究尼日利亚西南部降雨率的季节特征及其对地球卫星通信中感应衰减的影响

对流层传播信道建模越来越受到科学界的关注，特别是在即将到来的高频卫星通信系统的应用中。信道建模对于预测链路性能至关重要，例如在单用户场景和多用户场景下的误码率（BER）方面，尤其是在吞吐量和延迟方面。本研究调查了尼日利亚选定热带地区降雨率和降雨引起的衰减的季节性特征，即超额降雨量和最坏月份降雨量统计。还分析了降雨率的变异系数（CV），以研究由于所选地区的不均匀性而导致的降雨率的变异性。GPM 卫星 30 分钟的降雨率数据被用于通过 30 分钟到 1 分钟的公制转换模型进行雨量衰减预测。通过在阿库雷站点对 12.275 GHz 频率的雨衰减进行为期两年（2013-2014 年）的信标测量，对雨衰减进行了验证。根据雨衰减信标测量结果，对 ITU-R 618-13 (2017) 雨衰减模型进行了修改。修改后的 ITU-R 模型与 23.5 RMSE 的 ITU-R 模型相比，产生了 6.4 的最小均方根误差 (RMSE)。衰减差异随着频率差异向高频段移动而减小。ITU-R 模型高估了从 GPM 得出的计算结果，这表明 ITU-R 模型针对热带地区进行了修改。30 千兆赫衰减的空间变化显示，密集季节和干旱季节的衰减诱导值分别最高和最低。这些结果可用于功率增强型卫星系统，以在研究地区实现良好的信号可用性。

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来源期刊

Journal of Atmospheric and Solar-Terrestrial Physics 地学-地球化学与地球物理

CiteScore

4.10

自引率

5.30%

发文量

审稿时长

6 months

期刊介绍： The Journal of Atmospheric and Solar-Terrestrial Physics (JASTP) is an international journal concerned with the inter-disciplinary science of the Earth''s atmospheric and space environment, especially the highly varied and highly variable physical phenomena that occur in this natural laboratory and the processes that couple them. The journal covers the physical processes operating in the troposphere, stratosphere, mesosphere, thermosphere, ionosphere, magnetosphere, the Sun, interplanetary medium, and heliosphere. Phenomena occurring in other "spheres", solar influences on climate, and supporting laboratory measurements are also considered. The journal deals especially with the coupling between the different regions. Solar flares, coronal mass ejections, and other energetic events on the Sun create interesting and important perturbations in the near-Earth space environment. The physics of such "space weather" is central to the Journal of Atmospheric and Solar-Terrestrial Physics and the journal welcomes papers that lead in the direction of a predictive understanding of the coupled system. Regarding the upper atmosphere, the subjects of aeronomy, geomagnetism and geoelectricity, auroral phenomena, radio wave propagation, and plasma instabilities, are examples within the broad field of solar-terrestrial physics which emphasise the energy exchange between the solar wind, the magnetospheric and ionospheric plasmas, and the neutral gas. In the lower atmosphere, topics covered range from mesoscale to global scale dynamics, to atmospheric electricity, lightning and its effects, and to anthropogenic changes.