Links between the complexities in atmospheric-soil energy exchange and temperature dynamics in tropical regions

Abstract

In this work, the variations in the dynamical complexities in soil temperature variations were compared with that of air temperature using measured temperature parameters from different stations located in Nigeria. These parameters were also compared to the monthly averages of rainfall. The data sets were analysed using nonlinear time series analytical techniques. The results reveal that the annual trend of dynamical complexity follows a reverse trend of the rainfall peak period and the Lyapunov exponent for the un-detrended air temperature time series does not follow the same annual trend as that of the soil temperature. Also, dynamical properties of the two parameters are highly associated with correlation coefficients that are in some cases as high as 0.85 especially for the entropy measure for both air and soil. It was observed, however, that the degree of correlations between these parameters varies with time and location. An observed graduated response of Tsallis entropy computed for detrended soil temperature revealed a steady increase of the values of Tsallis entropy from north to south of Nigeria across the geographical belts. The observed variations have been associated with varying atmospheric factors and the changes in the properties of the soil with location. These factors might be influential in conjunction with other factors in the air-soil interface.