نتایج جستجو برای: refractivity index

تعداد نتایج: 396554  

2008
Caglar Yardim Peter Gerstoft William S. Hodgkiss

This paper addresses the effects of sea clutter on the clutter-based atmospheric refractivity estimation techniques. It provides a mean square error (MSE) metric for refractivity estimators based on the available clutter-to-noise (CNR) ratio, the type of the sea clutter statistics (Rayleigh, K-distributed and log-normal) and the parameters forming these probability density functions (pdf) such ...

2010
Frank E. Jones

The air density equation of Jones, Edlen's dispersion formula for standard air, and Edlen's empiricallyderived expressions for the effects of CO 2 abundance and water vapor partial pressure on refractivity have been combined into a simplified equation for the refractivity of air, and estimates have been made of uncertainties in calculated refractivity. Under ambient conditions typical of metrol...

2013
J. C. NICOL A. J. ILLINGWORTH

Radar refractivity retrievals have the potential to accurately capture near-surface humidity fields from the phase change of ground clutter returns. In practice, phase changes are very noisy and the required smoothing will diminish large radial phase change gradients, leading to severe underestimates of large refractivity changes (DN). Tomitigate this, themean refractivity change over the field...

Journal: :Theoretical Foundations of Chemical Engineering 2021

The results of studying the physical properties a deep eutectic solvent based on choline chloride and sulfosalicylic acid have been presented. A phase diagram for this two-component mixture has constructed, dependences its density refractive index temperature studied first time. molar refractivity under study calculated. possibility using as an extractant recovery metal ions in solid–liquid sys...

2010
Fabrizio Pelliccia Stefania Bonafoni Patrizia Basili Piero Ciotti Nazzareno Pierdicca

In this study we have proposed a method based on neural networks to retrieve refractivity, temperature, pressure and humidity profiles by using FORMOSAT-3/COSMIC GPS radio occultation data. To overcome the constraint of an independent knowledge of one atmospheric parameter at each GPS occultation, we trained three neural networks with refractivity profiles as input computed from the geometrical...

2018
Thomas Sievert Joel Rasch Anders Carlström Mats I. Pettersson Viet Vu

High accuracy of impact height is important to get reliable Radio Occultation (RO) measurements of the atmosphere refractivity. We have made an investigation on how accurately we can measure the impact height at ground level using wave optics simulations, realistic refractivity profiles, a realistic simulator for an advanced RO instrument including noise, and using phase matching for the invers...

2008
A. Flores G. Ruffini

Tomographic techniques are successfully applied to obtain 4D images of the tropospheric refractivity in a local dense network. In the lower atmosphere both the small height and time scales and the non-dispersive nature of tropospheric delays require a more careful analysis of the data. We show how GPS data is processed to obtain the tropospheric slant delays using the GIPSY-OASIS II software an...

2008
Leslie A. Young

Calculation of a stellar occultation lightcurve from an assumed refractivity profile involves the integral of the refractivity or its derivatives along the line of sight through an atmosphere. For the general case, normal numerical integration can be time consuming for least-squares fitting with a modest number of free parameters, or for calculation at a fine grid for comparison with local refo...

Journal: :The Journal of Korean Institute of Electromagnetic Engineering and Science 2023

In this study, we propose a model for predicting atmospheric refractivity using meteorological data and deep learning. The purpose of study is to compare the prediction accuracy traditional interpolation methods proposed model, verify whether learning trained on can provide values closer true values, thus demonstrate potential utilizing in refractivity.

2016
Qixiang Liao Hanqing Shi Robert W. Talbot

In this paper, we present a new estimation of the atmospheric refractivity profile combining the scattering signal (electromagnetic wave propagation loss) and the direct signal (phase delay). The refractivity profile is modeled using four parameters, i.e., the gradient of the refractivity profile (c1, c2) and the vertical altitude (h1, h2). We apply the NSGA-II (Non-dominated Sorting Genetic Al...

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