Space-time model of refractive index applied to the surface atmospheric layer

Authors: Novikov A. V., Akulinichev Yu. P.

Annotation: Statistical model for refractive index space-time field is built on the basis of bimonthly measurements at seven height levels in atmospheric layer of 2–200 m above the ground. It includes the Fourier-series expansion for random temporary variations and the Karhunen-Loeve expansion for height variations. Two-scale approximation for time correlation functions is used both for the refractive index and its height gradient and numerical values of the approximation coefficients are given. It is found that random part of the refractive index height profile can be represented as a sum of two determined functions with random weights. As for height gradient, especially in the lower layer of 2–20 m, for good approximation three summands must be used.

Keywords: atmospheric refraction, refractive index, height profile, radio propagation, evaporation duct