Inferring refractivity profiles from radar sea clutter is a complex nonlinear optimization problem. Previous works treat this problem as a model parameter estimation issue by using some idealized refractivity models, such as the Log linear evaporation duct model, bilinear model, and trilinear model, to describe the synoptic structure of the real atmospheric conditions. However, these idealized ...

This paper estimates lower atmospheric refractivity (M-profile) given an electromagnetic (EM) propagation loss (PL) measurement. Specifically, height-independent PL measurements over a range of 10–80 km are used to infer information about the existence and potential parameters of atmospheric ducts in the lowest 1 km of the atmosphere. The main improvement made on previous refractivity estimatio...

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 ...

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...

In this article, at first, a quantitative structure–property relationship (QSPR) model for estimation of the normal boiling point of liquid amines is developed. QSPR study based multiple linear regression was applied to predict the boiling points of primary, secondary and tertiary amines. The geometry of all amines was optimized by the semi-empirical method AM1 and used to calculate different t...

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...

This paper reports on different physical and optical properties of Nd3+-doped bismuth borate glasses. The glasses containing Nd3+ in (25 − x)Bi2O3:20Li2O:20ZnO:35B2O3:xNd2O3 (where x = 1, 1.5, 2 mol%) have been prepared by melt-quenching method. The amorphous nature of the glasses was confirmed by X-ray diffraction studies. The physical parameters like dielectric constant, refractive index, ion...

ABSTRACT. Linear, nonlinear optical properties, photon buildup factors, and neutron shielding capability of glasses with chemical composition (65-x)B2O3-10Sb2O3-25Li2O-xBi2O3, where x = 0 (BSLB0) – 20 (BSLB20) mol% steps 4 were examined. Molar refractivity (Rmolar) molar polarizability (αmolar) increased as Bi2O3 content increase in the examined BSLB-glasses. The values metallization criterion ...

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...