Ducting and Turbulence Effects on Radio-Wave Propagation in an Atmospheric Boundary Layer

Abstract

Abstract-The split-step Fourier (SSF) algorithm is applied to simulate the propagation of radio waves in an atmospheric duct. The refractive-index fluctuation in the ducts is assumed to follow a twodimensional Kolmogorov power spectrum, which is derived from its three-dimensional counterpart via the Wiener-Khinchin theorem. The measured profiles of temperature, humidity and wind speed in the Gulf area on April 28, 1996, are used to derive the average refractive index and the scaling parameters in order to estimate the outer scale and the structure constant of turbulence in the atmospheric boundary layer (ABL). Simulation results show significant turbulence effects above sea in daytime, under stable conditions, which are attributed to the presence of atmospheric ducts. Weak turbulence effects are observed over lands in daytime, under unstable conditions, in which the high surface temperature prevents the formation of ducts.

Wildfire Smoke Particulate Matter Concentration Measurements Using Radio Links From Cellular Communication Networks

“…The scaling approach (Monin-Obukhov) can be used to describe the turbulence within the ABL using a defined set of parameters (Frehlich, 2000). The propagation of the EM waves can be described using the Helmholtz wave equation and solved using a split-step Fourier algorithm (Chou & Kiang, 2014). The aim of this paper is not to simulate EM propagation, but theoretical basics are presented here to guide the discussion on the results, which are extracted from case-study observations of radio link RSLs within the ABL.…”

“…This enables the effect of turbulence on refractive index fluctuations to be taken into account, in addition to the larger scale layering of the refractivity. Chou and Kiang (2014) used a split-step Fourier approach to simulate real case-study observations of vertical profiles of refractivity in order to evaluate the effect of turbulence on EM propagation in the occurrence of ducts and for different ABL conditions. They show that in the unstable case, the effect of turbulence is negligible, while in the stable case, the effect of mechanical turbulence induces energy leakage from ducting and nonducting regions and leads to a more uniform distribution of signal attenuation within the duct.…”

Retrieval of Refractivity Profile With Ground-Based Radio Occultation by Using an Improved Harmony Search Algorithm

“…Global coverage of refractivity profiles is useful to predict weather conditions in the troposphere and the lower stratosphere [5,6], to study heavy precipitation [7], Arctic atmosphere [8], severe weather events [9,10], and over-the-horizon communication channels [11].…”