Comparison of Ku-band satellite rain attenuation with ITU-R prediction models in the tropics

2013 ◽  
Author(s):  
A.A.H. Yaccop ◽  
Y.D. Yao ◽  
A.F. Ismail ◽  
K. Badron
Keyword(s):  
Prediction Models ◽  
Rain Attenuation ◽  
The Tropics ◽  
Ku Band

scholarly journals Performance evaluation of some rain attenuation prediction models at coastal locations at 12 and 40 GHz

2021 ◽  
Vol 6 (2) ◽  
pp. 27-37
Author(s):  
Abayomi Isiaka O. Yussuff ◽  
◽  
Kabir Momoh ◽  
Keyword(s):  
Rain Rate ◽  
Prediction Models ◽  
Service Providers ◽  
Service Level ◽  
Rain Attenuation ◽  
Rainfall Data ◽  
Integration Time ◽  
Tropical Regions ◽  
Attenuation Models ◽  
The Tropics

This work concerns the evaluation of the performances of some selected rain attenuation models at two different locations in Lagos, Nigeria at 12 and 40 GHz. Scarcity of rainfall data in the tropical regions resulted in abysmal research efforts into the causes and solutions to satellite signal outages, this was further exacerbated by the convective tropical rain precipitations. The globally adopted ITU-R model, had been declared unsuitable for predicting rain attenuation in the tropics by several researchers in the literature. Two-year (January 2016 to December 2017) local rainfall data were sourced from the Nigerian Meteorological Services (NIMET) for two coastal stations (Ikeja and Oshodi). Rain attenuation exceeded for rain rate at 0.01% of the time, was computed after the 1-hour rain rate integration time which was sourced from NIMET was converted to 1-minute integration time. Attenuation exceeded for other percentages of time were also obtained using statistical interpolation and extrapolation methods. The collected data were tested with ITU-R, SST, SAM, DAH and Silva Mello et al. For Ikeja at 12 GHz, the SST was observed to closely match the measurement attenuation at 0.01%≤p≤1% of time exceeded; closely followed by Silver Mello. For Oshodi also at 12 GHz, SST intersected with the measured attenuation at 0.01%≤p≤0.03%, and p=0.1% of time. However, at 40 GHz, all the prediction models performed poorly by underestimating the measurement for Ikeja, although SST showed the best effort. The SST model matched the measurement, especially at p=0.03% and p=0.5% for Oshodi at 40 GHz, closely followed by Silva Mello which matched the measurement at p=0.05% and p=0.1%, while ITU-R, SAM and DAH largely underestimated the measurement. The SST was therefore affirmed the overall best performed rain attenuation prediction model for both stations at both frequency bands; closely followed by the Silva Mello. ITU-R, SAM and DAH on the other hand performed poorly. The findings arising from this work could present useful information to satellite equipment designers and manufacturers, while at the same time ensuring that service providers conform to the required service level agreements

scholarly journals Development of software for Ku-Band signal availability due to rain attenuation

2019 ◽  
Vol 13 (3) ◽  
pp. 1252
Author(s):  
Norsuzila Ya’acob ◽  
Noraisyah Tajudin ◽  
Muhammad Rezza Alui ◽  
Nani Fadzlina Naim ◽  
Murizah Kassim ◽  
...  
Keyword(s):  
Satellite Communication ◽  
Rain Rate ◽  
Prediction Models ◽  
Weather Prediction ◽  
Rain Attenuation ◽  
Cumulative Distribution ◽  
One Year ◽  
Satellite Dish ◽  
Band Signal ◽  
Ku Band

<span>Ku-Band signal is often used for satellite communication mainly for direct to home (DTH) broadcasting. One of the major issues using this band is that the signal will be affected by raindrops. Raindrops absorb and scatter signal that operates at a frequency of more than 10 GHz. However, studies have been done to predict and measure the rainfall rate and rain attenuation. The rain attenuation in Ku-Band range and the rain rate were measured at satellite receiving dish, pointed towards the orbital slot 91.5 E over a one-year period in 2013. The cumulative distribution of rain rate obtained as well as a cumulative distribution of rain attenuation obtained are presented and compared with the rain prediction models. The aim is to get the best model to be used for the purpose of software development. It was found out that the DAH prediction model is fairly equitable when compared to direct satellite dish receiving measurements in Malaysia. The model provided a suitable baseline in developing a user interface software for weather prediction.</span>

scholarly journals An Evaluation of Precipitation Forecasts from Operational Models and Reanalyses Including Precipitation Variations Associated with MJO Activity

2010 ◽  
Vol 138 (12) ◽  
pp. 4542-4560 ◽  
Author(s):  
John E. Janowiak ◽  
Peter Bauer ◽  
Wanqiu Wang ◽  
Phillip A. Arkin ◽  
Jon Gottschalck
Keyword(s):  
Prediction Models ◽  
Coupled Model ◽  
Warm Season ◽  
Temporal Correlation ◽  
Operational Model ◽  
Temporal Correlations ◽  
Operational Models ◽  
Environmental Prediction ◽  
The Tropics ◽  
Model Precipitation

Abstract In this paper, the results of an examination of precipitation forecasts for 1–30-day leads from global models run at the European Centre for Medium-Range Weather Forecasts (ECMWF) and the National Centers for Environmental Prediction (NCEP) during November 2007–February 2008 are presented. The performance of the model precipitation forecasts are examined in global and regional contexts, and results of a case study of precipitation variations that are associated with a moderate to strong Madden–Julian oscillation (MJO) event are presented. The precipitation forecasts from the ECMWF and NCEP operational prediction models have nearly identical temporal correlation with observed precipitation at forecast leads from 2 to 9 days over the Northern Hemisphere during the cool season, despite the higher resolution of the ECMWF operational model, while the ECMWF operational model forecasts are slightly better in the tropics and the Southern Hemisphere during the warm season. The ECMWF Re-Analysis Interim (ERA-Interim) precipitation forecasts perform only slightly worse than the NCEP operational model, while NCEP’s Climate Forecast System low-resolution coupled model forecasts perform the worst among the four models. In terms of bias, the ECMWF operational model performs the best among the four model forecasts that were examined, particularly with respect to the ITCZ regions in both the Atlantic and Pacific. Local temporal correlations that were computed on daily precipitation totals for day-2 forecasts against observations indicate that the operational models at ECMWF and NCEP perform the best during the 4-month study period, and that all of the models have low to insignificant correlations over land and over much of the tropics. They perform the best in subtropical and extratropical oceanic regions. Also presented are results that show that striking improvements have been made over the past two decades in the ability of the models to represent precipitation variations that are associated with MJO. The model precipitation forecasts exhibit the ability to characterize the evolution of precipitation variations during a moderate–strong period of MJO conditions for forecast leads as long as 10 days.

Analysis of Selected Earth-Space Rain Attenuation Models for a Tropical Station

2016 ◽  
Vol 3 (2) ◽  
pp. 383 ◽  
Author(s):  
A. I. O. Yussuff
Keyword(s):  
Prediction Models ◽  
Measurement Data ◽  
Daily Rainfall ◽  
Rain Attenuation ◽  
Propagation Path ◽  
Tropical Regions ◽  
Earth Space ◽  
Budget Analysis ◽  
Link Budget ◽  
Attenuation Models

The restrained use of millimeter bands is due to severe rain attenuation. Attenuation is caused when rain cells intersects radio wave’s propagation path; resulting in deep fades. The effect of rainfall is more severe in tropical regions characterized by heavy rainfall intensity and large raindrops; hence, rain attenuation analyses are essential to study rain fade characteristics for use in earth-space link budget analysis, for outage prediction resulting from rain attenuation. Tropical regions are particularly challenged with signal outage, necessitating the formulation and development of suitable prediction model(s) for the region. Therefore, extensive knowledge of the propagation phenomena mitigating system availability and signal quality in these bands are required. Daily rainfall data were collected from the Nigerian Meteorological Services for Lagos for spanning January to December 2010. Results showed that although, the ITU-R model out-performed the other prediction models under consideration, none of prediction models matched the measurement data.

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