Atmospheric chaoticity and complexity from radio refractivity derived from Akure station

Abstract

Understanding the hidden dynamics of the atmosphere and its effect on radio wave propagation is paramount. Therefore proper characterization of atmospheric dynamics especially for its annual and seasonal variation is necessary. In this paper, atmospheric weather parameters (pressure, relative humidity and temperature), were used to obtain the radio refractivity at the surface Ns level, at 100 m height, N100 and the differential radio refractivity dN/dH. The extracted radio refractivity parameters were characterized based on chaoticity and dynamical complexity, for Akure meteorological station (7°15′9.22″N, 5°11′35.23″E). The data analysis has been based on the Combined application of Largest Lyapunov Exponent and Tsallis Entropy (CLLETE). The data sets for the year 2011 and 2012 have been used for the computation. It was observed that the CLLETE parameters follow similar trend in most cases, and the Lyapunov exponent is generally positive indicating the presence of chaos for all radio refractivity data sets. It was further revealed that the pattern of the dynamical complexity variations in 2012 follow a similar trend from July to December for N100 and dN/dH with the values of the dynamical complexity parameters computed for NS having a huge departure from the other two heights with lower complexity values. However, the dynamical complexity parameters computed for NS and N100 a have similar a trend from the beginning of the year to June. The values of the Chaos and complexity parameters also show a similar variation in 2011 with NS following the same trend between July and December. This indicates the dynamical response of radio refractivity to varying weather conditions.