Use of radiosonde data in propagation prediction

Statistical Analysis of Refractivity Gradient and $\beta_{0}$ Parameter in the Gulf Region

“…less negative) than usual, or even positive, sub-refraction occurs, where the ray bends less than usual towards the earth, even bending upwards in the case of a positive gradient and the range reduces. Sub-refraction occurs when warm moist air flows over a cool ocean surface or over a cooler air mass just above the ocean surface [2,17].…”

“…β 0 represents the percentage of time in which the value of ΔN is less than or equal to -100 N/km [1,2,5]. It is derived from ΔN statistics in the lowest 100 m of the atmosphere.…”

“…Anomalous propagation may occur due to nonstandard variation of vertical refractivity through different atmospheric layers. Several studies related to the refractivity analysis are available [2][3][4][5][6][7]. Only a few studies are available for the Gulf region although it is likely to experience abnormal conditions due to its special climate which is hot and humid, most of the year.…”

New Methodology for Predicting Vertical Atmospheric Profile and Propagation Parameters in Subtropical Arabian Gulf Region

“…The k-factor can be calculated from the rate of change of the refractive index with height and the actual Earth's radius, a, using Snell's law in spherical geometry, knowing that N = (n-1) × 10 6 , where a is given by unit of nmi (a = 6371 km = 3440 nmi). The k-factor value must be multiplied by the actual Earth's radius, a, in order to plot the propagation paths as straight lines [1,3].…”

“…Some linear and exponential models [2,4,5] have been proposed to estimate the vertical profile from existing N s data. Several studies on refractivity analysis have been carried out for temperate climates all over the world [6][7][8][9][10][11], while a few are available for the unique subtropical climate of the Arabian Gulf region [12][13][14][15][16][17]. Three important atmospheric layers, namely 65 m, 100 m and 1 km layers above the ground are analyzed and the relevant propagation parameters are derived for the design of terrestrial communication systems operating in such climate.…”