Modified heat-meter method for determining soil heat flux

The theory of heat-flux meters describing the perturbation of a uniform, steady heat flux through a porous medium (soil) by a meter of different thermal conductivity was tested and confirmed under laboratory conditions. From the theory, an equation was derived for determining the heat flux density through the medium which is more accurate than direct calibration equations. The medium heat flux density is found by first calibrating a heat meter independently in two other media differing in thermal conductivity. Then, once the meter is inserted into the medium of interest, its signal and the temperature gradient in the direction of heat flow at 3–6 cm from the meter are measured. The method should serve to provide for more accurate assessment of energy budget of the earth's surface.