Proceedings Article•
Use of WRF model to characterize propagation effects in the troposphere
08 Apr 2013-pp 1377-1381
TL;DR: In this article, the authors take advantage of the Weather Research and Forecasting (WRF) system, capable of providing reanalysis and forecasts at high resolution, to simulate the atmospheric conditions, to finally estimate the signal attenuation for slant path satellite links beyond 10 GHz.
Abstract: Next generations of satellite communication systems demand the use of high frequency bands and the effect of the troposphere at these frequencies has a major impact in the signal attenuation. In this context, the objective of the work presented in this paper is to take advantage of the Weather Research and Forecasting (WRF) system, capable of providing reanalysis and forecasts at high resolution, to be able to simulate the atmospheric conditions, to finally estimate the signal attenuation for slant path satellite links beyond 10 GHz. This is of paramount importance to effectively supplant the lack of measurements for the design of new satellite systems.
Citations
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06 Apr 2014
TL;DR: In this article, the propagation conditions for Earth observation data downlink operating at the Ka band were modeled by using numerical weather forecast models to perform local high-resolution reanalysis of the meteorological conditions on which the propagation effects can be computed.
Abstract: This paper describes a methodology to model the propagation conditions for Earth observation data downlink operating at Ka band. It relies on the use of numerical weather forecast models to perform local high resolution reanalysis of the meteorological conditions on which the propagation effects can be computed. From the meteorological simulations spanning long durations, time series representative of attenuation between an orbiting satellite and a ground station are extracted, knowing orbital and RF characteristics of the system.
21 citations
Cites background or methods from "Use of WRF model to characterize pr..."
...The aim of the simulator developed is to perform local reanalysis of past weat her conditions using WRF (Weather Research and Forecasting) model and then to turn them into propagation parameters for a LEO to ground link [6,7] ....
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...The way to convert the various meteorological fields at a given time in to specific attenuation can be found in [6] ....
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TL;DR: In this paper, the authors used the Weather Research and Forecasting (WRF) software and investigated Numerical Weather Prediction (NWP) models as an alternative source of nonrainy attenuation time series.
Abstract: In order to keep up with the demand for new services, future satellite-to-ground communications will operate at higher frequencies, notably in the 20–50 GHz bands. Consequently, new challenges arise for system designers as the attenuation of the signal crossing the troposphere increases with frequency. Propagation experiments, such as the on-going Alphasat campaign, provide direct measurements of the attenuation. However, other data sources, such as collocated radiometers, are needed to recover the attenuation in nonrainy conditions. This paper uses the Weather Research and Forecasting (WRF) software and investigates Numerical Weather Prediction (NWP) models as an alternative source of nonrainy attenuation time series. Four months of measured Alphasat and radiometric signals collected at Spino d’Adda serve as the reference to assess the accuracy of NWP-derived attenuation. The best agreement between the NWP-derived and the radiometric nonrainy attenuations is achieved with the Tiedtke cumulus scheme. Considering the limits in accuracy inherent to the propagation and radiometric data, the resulting total attenuation statistics are acceptable. The results are expected to improve further with NWP simulation domains closer to the state of the art.
18 citations
TL;DR: The upcoming migration of satellite services to higher bands, namely, the Ka and Q/V bands, offers many advantages in terms of bandwidth and system capacity as mentioned in this paper, however, it poses challenges a...
Abstract: Summary The upcoming migration of satellite services to higher bands, namely, the Ka‐ and Q/V‐bands, offers many advantages in terms of bandwidth and system capacity. However, it poses challenges a...
14 citations
Cites methods from "Use of WRF model to characterize pr..."
...Postprocessing the WRF 2‐km grid output as in Outeiral García et al.43 The meteorological variables are converted into specific attenuations according to ITU‐...
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...Postprocessing the WRF 2‐km grid output as in Outeiral García et al.(43) The meteorological variables are converted into specific attenuations according to ITU‐R P....
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TL;DR: In this paper, a comprehensive methodology to assess tropospheric effects affecting high-frequency earth-space communication systems is presented, taking advantage of physically based approaches aimed at synthesizing high-resolution (1 km $\times1$ km horizontal, 100m vertical) 3D fields of rain, clouds, and water vapor.
Abstract: ATMospheric simulator for PROPagation applications (ATM PROP), a comprehensive methodology to assess tropospheric effects affecting high-frequency earth–space communication systems, is presented. The model takes advantage of physically based approaches aimed at synthesizing high-resolution (1 km $\times1$ km horizontal, 100-m vertical) 3-D fields of rain, clouds, and water vapor (dimension: 200 km $\times200$ km horizontal, 20-km vertical), which are all merged so as to maintain their mutual correlation. This, in turn, enables a more realistic combination of the attenuation due to single constituents, if compared to the statistical approach currently recommended by the ITU-R. The accuracy of ATM PROP in predicting tropospheric effects on earth–space systems is initially validated against the large propagation data set collected at the experimental station of Spino d’Adda, Italy, during the ITALSAT propagation campaign. The preliminary results obtained suggest that ATM PROP can be used to predict, with a reasonable level of complexity and limited coarse-resolution Numerical Weather Prediction-derived inputs, the tropospheric fade affecting complex communication systems (e.g., site diversity schemes), especially those involving low elevation links (e.g., low earth orbit or geostationary orbit at high latitude), for which the spatial distribution of the relevant tropospheric constituents needs to be taken in due account.
10 citations
Cites background from "Use of WRF model to characterize pr..."
...Some of these methodologies are inherently limited as they consider only single constituents (see [8]–[12] for rain, [13] and [14] for clouds, and [15] for water vapor), while others (see [16] and [17]),...
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TL;DR: In this paper, a WF-based technique was proposed to predict data volume transfer during deep-space satellite communication links at the Ka- and X-band where the Earth's atmosphere affects propagating signals.
Abstract: This paper aims at improving and assessing a previously developed technique to predict data volume transfer during deep-space satellite communication links at Ka - and ${X}$ -band (where the Earth’s atmosphere affects propagating signals). The proposed technique exploits a weather forecast (WF) model to predict the atmospheric state and a radiative transfer model to convert the atmospheric state into radiopropagation variables. The latter are used to design the link budget and to maximize transferred data-volume. This WF-based technique exploits the atmospheric attenuation as a random variable related to the statistic of the transmission error rate that drives the received data-volume and its uncertainty. The WF-based technique is evaluated for the test case of the BepiColombo mission to Mercury from ESA (European space agency) considering Cebreros and Malargue receiving ground-stations. Tuning and verification of the adopted models were accomplished exploiting ground-based meteorological measurements (weather stations, radiosoundings, and microwave radiometer) and simulating four years of data transmission. Results, in terms of yearly received data-volume and its uncertainty, highlight the advantages of short-term WF-based atmospheric statistics in opposition to the commonly used long-term climatological statistics. These advantages are evaluated at both Ka- and ${X}$ -band. The use of aggregated statistics derived from WF data is demonstrated as a reliable possibility of bypassing the lack of meteorological measurements.
9 citations
Additional excerpts
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References
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Book•
01 Jan 1983
TL;DR: In this paper, a Potpourri of Particles is used to describe surface modes in small Particles and the Angular Dependence of Scattering is shown to be a function of the size of the particles.
Abstract: BASIC THEORY. Electromagnetic Theory. Absorption and Scattering by an Arbitrary Particle. Absorption and Scattering by a Sphere. Particles Small Compared with the Wavelength. Rayleigh--Gans Theory. Geometrical Optics. A Potpourri of Particles. OPTICAL PROPERTIES OF BULK MATTER. Classical Theories of Optical Constants. Measured Optical Properties. OPTICAL PROPERTIES OF PARTICLES. Extinction. Surface Modes in Small Particles. Angular Dependence of Scattering. A Miscellany of Applications. Appendices. References. Index.
16,859 citations
TL;DR: Light scattering by small particles as mentioned in this paper, Light scattering by Small Particle Scattering (LPS), Light scattering with small particles (LSC), Light Scattering by Small Parts (LSP),
Abstract: Light scattering by small particles , Light scattering by small particles , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی
9,737 citations
Book•
01 Dec 1981
TL;DR: Light scattering by small particles as mentioned in this paper, Light scattering by Small Particle Scattering (LPS), Light scattering with small particles (LSC), Light Scattering by Small Parts (LSP),
Abstract: Light scattering by small particles , Light scattering by small particles , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی
6,623 citations
"Use of WRF model to characterize pr..." refers background in this paper
...The necessary formulation of both theories is presented in [9][10]....
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...Conversion of rain water mixing ration into rain specific attenuation The specific attenuation due to rain R γ [dB/Km] is related to the raindrop size distribution [9][12] by:...
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TL;DR: A critical survey of the literature is presented and an empirical model of the complex refractive indices for ice and liquid water is constructed from this review.
Abstract: A critical survey of the literature is presented. An empirical model of the complex refractive indices for ice and liquid water is constructed from this review. The model is applicable from -20 degrees C to 0 degrees C for ice and from -20 degrees C to 50 degrees C for water. The spectral interval for which the model applies extends from 2 micro, to several thousand kilometers in wavelength for ice and from 2 micro to several hundred meters in wavelength for water.
595 citations
"Use of WRF model to characterize pr..." refers methods in this paper
...The aim of this paper is to present a methodology to acquire the profiles of attenuation due to gases [4][5], clouds [6][7] and rain [8]-[17] in the troposphere by handling the output parameters of the WRF Model....
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01 Jan 1986
TL;DR: In this article, the effects of atmospheric gases, primarily oxygen and water vapor at space communications frequencies, are discussed, and methods for calculating the expected attenuation for a radiowave link are presented.
Abstract: A radiowave propagating through the Earth’s atmosphere will experience a reduction in signal level due to the gaseous components present in the transmission path. Signal degradation can be minor or severe, depending on frequency, temperature, pressure, and water vapor concentration. In this chapter the effects of atmospheric gases, primarily oxygen and water vapor at space communications frequencies, are discussed, and methods for calculating the expected attenuation for a radiowave link are presented. Examples are given for atmospheric attenuation at several of the frequencies of interest for space communications systems. Atmospheric gases also affect radio communications by adding atmospheric noise (i.e., radio noise) to the link. This problem is described fully in Chapter 7.
417 citations