Gold-deposited optical fiber sensors with film thicknesses from 30 to 60 nm were prepared, and the responses to a wide range of a refractivity (1.33-1.54 refractive index (RI) units) were investigated both experimentally and theoretically. The response curve of the sensor has two minima in the refractivity range from 1.33 to 1.44 and at 1.462 RI units. The former minimum is due to surface plasm...

The theoretical background and present status of formulas for the refractive index of air are reviewed. In supplement to Edlén's recently revised formula for relative refractivity, the density dependence of refractive index is reanalyzed. New formulas are presented for both phase and group refractive index which are more useful over a wide range of pressure, temperature, and composition than an...

The paper describes possibilities of refractive index height profile estimations using field measurement at a receiver site of a terrestrial point-to-point link in terms of angleof-arrival (AOA) spectra. Several refractivity models based on orthogonal function set are introduced to improve the estimation accuracy.

Radio refractivity plays a significant role in the development and design of radio systems for attaining the best level of performance. Refractivity in the troposphere is one of the features affecting electromagnetic waves, and hence the communication system interrupts. In this work, a modified artificial neural network (ANN) based model is applied to predict the refractivity. The suggested ANN...

In coastal regions the presence of the marine boundary layer can significantly affect RF propagation. The relatively high specific humidity of the underlying “marine layer” creates elevated trapping layers in the radio refractivity structure. While direct sensing techniques provide good data, they are limited in their temporal and spatial scope. There is a need for assessing the three-dimension...

The Advanced Regional Prediction System (ARPS) three-dimensional variational (3DVAR) system is enhanced to include the analysis of radar-derived refractivity measurements. These refractivity data are most sensitive to atmospheric moisture content and provide high-resolution information on near-surface moisture that is important to convective initiation (CI) and precipitation forecasting. Observ...

In this study a nonlocal, linear observation operator for assimilating radio occultation data is evaluated. The operator consists of modeling the excess phase, that is, integrating the refractivity along straight lines tangent to rays, below a certain height. The corresponding observable is the excess phase integrated through the Abel-retrieved refractivity, along the same lines, below the same...

in this paper, some meteorological data, such as temperature, pressure and dew point temperature are used for extracting the atmospheric refractivity in different locations of iran. these data have been measured at different heights in twelve radiosonde sites of country by using meteorological balloons. the set of refractivity points obtained from data of each site are plotted as a function of ...

40 The ARPS 3DVAR system is enhanced to include the analysis of radar-derived 41 refractivity measurements. These refractivity data are most sensitive to atmospheric moisture 42 content and provide high-resolution information on near-surface moisture that is important to 43 convective initiation (CI) and precipitation forecasting. Observing system simulation 44 experiments (OSSEs) are performed...

[1] Radio occultation remote sensing of the Earth’s atmosphere by use of GPS encounters problems in the moist lower troposphere (planetary boundary layer). The negative errors in retrieved refractivity (bias) may not be explained by the horizontal inhomogeneity in refractivity. In part, these errors can be attributed to the use of signal tracking algorithms inappropriate for the complicated str...