Soil Heat Flux Plate

Introduction the hfp01 outputs a voltage signal that is proportional to the heat flux of the surrounding medium usually soil.

Soil heat flux plate.

These include heat flow distortion and ther mal contact resistance philip 1961. 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 heat flux in the. 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.

4 6 2 simple parameterizations in some climate and general circulation models the ground heat flux is simply neglected. Soil heat flux is important because its couples surface energy balance with energy transfer processes in the soil 64 and affects the soil surface 61 and soil temperatures. 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. To convert this measured voltage to heat flux it must be divided by the plate s calibration constant.

These plates differed in size shape and composition sauer et al 2003. 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. Implementation of the standard heat flux plate method at the bare soil site pairs of four types of heat flux plates were used table 2. It is typically used for energy balance or bowen ratio flux systems.

And peng et al. Model hfp01 soil heat flux plate 1. Sites with heterogeneous media may require additional sensors. Two sensors may provide spatial averaging.

The soil heat flux at the bottom of this layer is also estimated rather than measured with a heat flux plate. The plates were installed in random order at 20 cm spacing along a north south transect. Surface soil heat flux density g calculated using a heat flux plate at 0 02 m depth g 2 and the change in heat storage d s estimated from temperature change at 0 01 m depth versus g 2 alone using half hour data collected under 0 10 m tall cool season grass. The popularity of this method is due to its simplicity.

However several potentially sig nificant errors may occurwhen using soil heat flux plates in the field.