Campbell Scientific HFT3 REBS Soil Heat Flux Plate - Manual (Page 6)

Model HFT3 Soil Heat Flux Plate
2
2 cm
6 cm
8 cm
Ground Surface
Up to 1 m
2.5 cm
FIGURE 1. Placement of Heat Flux Plates
3. Installation
The HFT3 Soil Heat Flux plates, the TCAV Averaging Soil Temperature
probes, and the CS615 Water Content Reflectometer are installed as shown in
Figure 1.
The location of the heat flux plates and thermocouples should be chosen to be
representative of the area under study. If the ground cover is extremely varied,
it may be necessary to have additional sensors to provide a valid average of soil
heat flux.
Use a small shovel to make a vertical slice in the soil. Excavate the soil to one
side of the slice. Keep this soil intact so that is can be replaced with minimal
disruption.
The sensors are installed in the undisturbed face of the hole. Measure the
sensor depths from the top of the hole. With a small knife, make a horizontal
cut eight cm below the surface into the undisturbed face of the hole. Insert the
heat flux plate into the horizontal cut.
Install the HFT3 in the soil such that the side with the white dot is
facing the sky.
In order for the HFT3 to make quality soil heat flux
measurements, the plate must be in full contact with the
soil.
NOTE
CAUTION
Partial emplacement of the HFT3 and the TCAV
sensors is shown for illustration purposes. All
sensors must be completely inserted into the soil face
before the hole is backfilled.