Cumulative distributions of rainfall rate and microwave attenuation in Singapore's tropical region

Abstract

Abstract. The microwave attenuation due to rainfall in tropical regions has not been very widely studied yet. In Singapore's tropical environment, line-of-sight microwave communication links were set up and have been operated for several years to study the microwave attenuation characteristics due to tropical rainfall. In this paper the experimental results are presented, including the cumulative distributions of rainfall rate, the cumulative distributions of microwave attenuation, the relationship between specific attenuation and rainfall rate, and frequency scaling formulae. The results show that the rainfall rate and the microwave propagation characteristics in Singapore over a 10-month experiment period are out of accord with International Radio Consultative Committee predictions. IntroductionWith the increasing requirement and establishment of more and more communications systems, it becomes necessary to study the microwave attenuation Experiment Setup and Data AnalysisThe distance between the transmitters and receivers is set to be 1.1 km, with a slant angle of about 5 ø. The microwave communicators are operated at frequencies of 15 and 38.6 GI-Iz, transmitting and receiving horizontally polarized continuous waves. The detailed experiment setup and its parameters, as well 751

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

“…This is because the raindrop‐size distribution models employed in formulating these theoretical attenuation models are developed from research works in the northern hemisphere temperate zones which based their distribution models on propagation data obtained in the temperate climate zones [ Green , 2004]. And in recent times, evidences have shown the limitation of these distribution models when applied to equatorial, tropical or lower‐latitudes regions [ Ajayi , 1990; Maciel and Assis , 1990; Yeo et al , 1993; Zainal et al , 1993; Li et al , 1995; Zhou et al , 2000], etc. For these reasons, attenuation values in the minimum attenuation bounds which are produced by lower rain rates or small raindrop sizes (which seems to be common in the temperate zones) tend to be reasonably described by these theoretical models in Figure 7a.…”

“…It is also observed from Figure 7a that the ITU‐R [2007] model gives attenuation values that fall within the measured minimum, average and increases rapidly toward the measured maximum attenuation. Works in the tropics and equatorial climates from Nigeria [ Ajayi , 1990], Brazil [ Maciel and Assis , 1990], Malaysia [ Zainal et al , 1993], Singapore [ Yeo et al , 1993; Li et al , 1995; Zhou et al , 2000], and India [ Maitra , 2004] have confirmed large disparities between measured attenuation results and the ITU‐R predictions. This is because factors that make important contributions to propagation impairments in these climates (tropical or equatorial) are different from the northern temperate climates [ Green , 2004].…”

Outage Performance of Single/dual Polarized Fixed Wireless Access Links in Heavy Rain Climatic Regions

“…Microwave attenuation due to rain in these regions has not been widely investigated yet through experimental campaigns [4]. Therefore reliable physical models predicting the outage performance of a terrestrial link, based on the understanding of the rain process and the rainfall medium exhibiting a good performance are necessary for the telecommunications system designers.…”

“…Heavy rain climatic (subtropical and tropical) climatic regions are usually treated separately for the propagation modeling because of the specific characteristics of the rainfall medium [4,5]. Microwave attenuation due to rain in these regions has not been widely investigated yet through experimental campaigns [4].…”

Year to year variation of rainfall rate and rainfall regime in Ota, southwest Nigeria for the year 2012 to 2015

“…Due to this, the tropical region of the world is known for their high rainfall rate. Amongst other atmospheric phenomenon, rainfall has major attenuation effect on propagation of communication signals at frequencies above 10 GHz [2]. Rain is formed when large cloud droplets from water vapour coalesce until the cloud can no longer hold together.…”