Soil Heat Flux Plate

Two sensors may provide spatial averaging.

Soil heat flux plate.

A thin layer of a thermal heat sink compound with λ 0 18 w m 1 k 1 greater than the plate λ m 1 0 w m 1 k 1 did not increase g m in a clay soil but increased g m by 6 in quartz sand. The popularity of this method is due to its simplicity. The heat flux in the. However several potentially sig nificant errors may occurwhen using soil heat flux plates in the field.

A unique calibration constant is supplied with each sensor. It is typically used for energy balance or bowen ratio flux systems. Model hfp01 soil heat flux plate 1. If a heat flux plate is installed near the soil surface e g at 2 cm depth the plate might overestimate the soil heat flux by more than 20 as demonstrated by ochsner et al.

And peng et al. These plates differed in size shape and composition sauer et al 2003. The soil heat flux at the bottom of this layer is also estimated rather than measured with a heat flux plate. A 6 5 increase in g m was also observed for plates treated with the same heat sink compound in a silt loam soil under field conditions.

To convert this measured voltage to heat flux it must be divided by the plate s calibration constant. Introduction the hfp01 outputs a voltage signal that is proportional to the heat flux of the surrounding medium usually soil. These include heat flow distortion and ther mal contact resistance philip 1961. The soil heat flux gz is commonly measured with passive heat flux plates but self calibrating plates or additional corrections are required to obtain accurate data.

In an energy balance installation all sensors must be completely inserted into the soil face before the hole is backfilled. 4 6 2 simple parameterizations in some climate and general circulation models the ground heat flux is simply neglected. Sites with heterogeneous media may require additional sensors. Disk called a heat flux plate or heat flow transducer to measure g sauer 2002.

The plates were installed in random order at 20 cm spacing along a north south transect.