Analysis of soil temperature harmonics and filtering characteristics

Abstract

Soil temperature determines the biological, chemical and physical processes taking place, and the energy and mass exchanges at the soil-temperature interface. The incident solar energy determines the periodic variation of the soil temperatures and the attenuation with depth. Harmonic analysis of soil temperatures at various depths measured at Takoradi and Accra, Ghana, were performed using Fourier technique to determine the periodicities. The results show that the soil behaves like an energy filter and an electrical analogue was modeled to simulate the filtering characteristics of the soil. It was found that the soil acts as a filter of thermal radiation with a cut-off frequency of about 80 Hz, which agrees with the cut-off frequency predicted by the Fourier spectra.


Journal of Applied Science and Technology (JAST), Vol. 7, Nos. 1 & 2, 2002, pp. 8 – 13