TP01

The thermal properties probe (TP01) uses a heat-pulse method to determine the thermal diffusivity and thermal conductivity of soil.  The ratio of these two quantities is the heat capacity of the soil.  ISFS adds a front-end PIC-based microprocessor to trigger this probe to take a measurement every 3 hours, heating the soil for 3 minutes and measuring the time decay of the heat pulse to 0.1s resolution.  Further calculation of therrmal diffusivity and heat capacity are done in ISFS's R code.

Occasionally, we have tested the TP01 sensors folllowing the manufacturer's proceedure to embed them in agar gel, which acts like water without convective heat transfer.