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The relative, ∆n/∆T, and absolute, ∆n, changes of the refractive index in the
whole span of analyzed temperature of water, 6 ÷ 50 °C, is presented in the table
Table 8, below. It shows that for water the temperature corrections according to
Eq. (43) and Eq. (46) on the refractive index, n, and volumetric water content,
θ TDR , determined by TDR method are acceptable.
Table 8.
Corrected and non-corrected temperature errors of the measurement of the refractive
index, n, for water and the TDR measured values of its content, θ TDR
Measurement
∆n/∆T
∆n for
6 ≤ T ≤ 50 °C ∆θ/∆T
∆θ for
6 ≤ T ≤ 50 °C
without correction -0.0213 - 0.9798 -0.0037 - 0.9798
After correction on n according to Eq. (42) -0.0012 0.0414 -0.0001 0.0414
The temperature change of the refractive index, n, for peat soil having
constant volumetric water content equal to 0.87 in saturated conditions is
presented in Fig. 24. During the measurements the peat soil temperature changed
from 6 °C to 12 °C.
Fig. 24.
Influence of temperature on the refractive index, n, for peat soil and the results of
applied corrections
The temperature fluctuations caused the corresponding changes of the
refractive index from n (6 °C) = 8.30 to n (12 °C) = 8.14. The correction according
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