A Measurement of Heat Flux to the Soil

Abstract

In order to investigate the heat flux to the soil, the author carried out the observatious of soil temperature, the volume percent of dry soil, water and air be contained withn the soil from November to December in 1957 at Tateno, Ibaragi Pref.
The results are as follows;
1) The heat capacity (ρc) of the soil is calculated form following formla indirectly,
ρc=ρ(0.20x₁+x₂+0.24x₃)
where x₁, x₂ and x₃ be observed exactly by using volumenometer are volume percent of dry soil, water and air be contianed withn the soil, respectively, ρ is the density of the soil.
The heat capacities of some soils is shown in Tab. 1., and the daily course of the heat capacity of the soil layer from 0cm to -1cm is shown in Fig. 1. and it is recognized that the heat capacity shows higher value at about sunrise and lower at evening.
2) The heat fluxes to the soil which was calculated from the distributions of soil temperature is compared when the daily change of heat capacity in the soil surface layer was ignored or not, and it is certainly that both values are nearly equal as shown in Fig. 2.
3) Considerable agreement of the heat flux to the soil be calculated from the temperature distribution with that directly by heat flow meter was found as shown in Fig. 3.