Validation of analytical algorithms for the estimation of soil thermal properties using de Vries model

Abstract

Soil thermal conductivity, and diffusivity together with the damping depth of soil temperature computed using Amplitude decay, Phase shift, Harmonic (amplitude based and phase based), Arctangent, Logarithmic and conduction-convection algorithms were compared with those obtained from de Vries model. The amplitude decay algorithm yielded the most reliable values of the soil thermal properties of all the estimation methods with mean absolute error (MAE), root mean squared error (RMSE) and relative maximum error (RME) of 0.04, 0.05 and 5.63% respectively for soil thermal conductivity. Harmonic algorithm (using the amplitude of the first 4 harmonics) gave values of the soil thermal properties next to the amplitude decay algorithm with MAE, RMSE and RME values 0.41, 0.44 and 47.84% respectively for soil thermal conductivity.Higher error values were associated with the other algorithms. The Arctangent algorithm gave the most deviated values of soil thermal properties with RME of 156.83% for soil thermal conductivity. For soil moisture content between 0.168 and 0.189 (> critical soil moisture content) the values of the soil thermal properties of the loamy sand decreased with increasing soil moisture, while they increased with increasing soil aeration.

Estimation of In-Situ Heat Capacity and Thermal Diffusivity from Undisturbed Ground Temperature Profile Measured in Ground Heat Exchangers.

“…From that so-called damping depth, the wave of the oscillatory surface temperature begins a linear attenuation with depth in the interval located before the thermostatic zone (Figure 2). A practical approximation ratio is used to evaluate the damping depth by considering the depth where the surface temperature amplitude is reduced to e -1 (1/2.718 = 0.37) of its initial value [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][39][40][41]. Beyond the approximation ratio approach, several other mathematical equations have been proposed to evaluate the damping depth.…”

“…Beyond the approximation ratio approach, several other mathematical equations have been proposed to evaluate the damping depth. Those are based on the sinusoidal propagation of surface temperature changes in the ground, the mean ambient temperature, or the temperature amplitude variation with depth/time [25][26][27][28][29][30][31][32][33][34][35][36][39][40][41][42]. The mathematical formulations are, for instance, the amplitude decay method, the phase lags method, or the inverse slope of a linear regression method [34,35].…”

“…In-situ TD can be inferred using the damping depth method, defined as [10,[22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40]:…”

“…The curve-fit between normalized ground temperature profile (Tg (z)) based on Eq. ( 1) against the measured temperature profile (Tobs (z)) at equilibrium state during the TRT [16,39] is plotted in Figure 7. The value of Zdd (Eq.…”

Modeling of diurnal pattern of air temperature in a tropical environment: Ile-Ife and Ibadan, Nigeria

“…The site comprises of an area of 850 m 2 of flat terrain at an elevation of 220 m above sea level. The soil type is loamy sand with bulk density of 1600 kgm −3 at 0.05 m depth (Adeniyi et al 2012a). The ground surface of the target area was bare during the measurement period.…”