The growing demand for Heat Pulse Probes (HPPs) to estimate thermal properties and surrogate soil processes comes with a need for improved standards for calibration and validation in reference materials. This study proposed air-free ice as a calibration material to determine the apparent rod spacing (r_c) for HPPs. The advantage of using air-free ice as a calibration standard over agar-stabilized water stems from the fact that at 0 °C ice provides a reference volumetric heat capacity (C_v = 1.93 MJ m⁻³ °C⁻¹), less than half that of water (C_v = 4.22 MJ m⁻³ °C⁻¹), while ice provides a four times larger reference thermal conductivity value (λ = 2.16 W m^{−1 o}C⁻¹) relative to that of water (λ = 0.56 W m⁻¹ °C⁻¹), which leads to a sharper peak temperature rise curve that may improve thermal property estimates in ice compared to the elongated peak obtained in water. We performed r_c calibrations with air-free ice in a freezer at −21 °C and agar-stabilized water at 21 °C using both Infinite-Line Source (ILS) and Identical-Cylinders Perfect-Conductors (ICPC) models to fit λ and C_v to temperature rise data and compute thermal diffusivity (κ) from the fitted λ and C_v (i.e., κ = λ/C_v). Results showed that the ICPC model yielded similar r_c values in both air-free ice and agar-stabilized water with reduced Total Error (TE) in estimating λ, C_v, and κ compared to results with the conventional ILS model. We suggest air-free ice as another standard for Heat Pulse Probe (HPP) rod spacing calibration and sensor-based thermal property validation.

对热脉冲探头 (HPP) 用于估计热特性和替代土壤过程的需求不断增长，因此需要改进参考材料的校准和验证标准。提出无空气的冰作为校准物质这项研究以确定表观杆间距（ř _Ç为高潜质）。与琼脂稳定水相比，使用无空气冰作为校准标准的优势源于这样一个事实，即在 0 °C 时冰提供的参考体积热容量 ( C _v  = 1.93 MJ m ^-3 °C ^-1 ) 小于水的一半 ( C _v  = 4.22 MJ m ^-3 °C ^-1)，而冰提供的参考热导率值 ( λ  = 2.16 W m ^{-1 o} C ^-1 ) 是水 ( λ  = 0.56 W m ^-1 °C ^-1 ) 的四倍，这导致更尖锐与在水中获得的拉长峰值相比，峰值温升曲线可以改善冰中的热特性估计。我们进行了[R _Ç同时使用校准用无空气的冰在冷冻在-21℃和琼脂稳定化水在21℃下无穷线源（ILS）与相同的圆柱体完美导体（ICPC）模型来拟合λ和ç _v到温升数据并根据拟合的λ和C _v（即，κ  =  λ / C _v）计算热扩散率 ( κ )。结果表明，ICPC模型产生类似ř _Ç在估计二者无空气冰和琼脂稳定水具有减小的总误差（TE）值λ，C _v，和κ与用常规的ILS模型的结果。我们建议将无空气冰作为热脉冲探头 (HPP) 棒间距校准和基于传感器的热性能验证的另一个标准。