Calculation method of coefficient of effective thermal diffusivity according to soil temperature measurements

Soil is a key link in the cycle of almost all the gaseous substances. Soil temperature is one of the most important characteristics. It is often measured on different objects. The soil thermal diffusivity characterizes the heat transfer processes in soil. The aim of this work is to obtain analytical formula for the calculation of this coefficient according to temperature measurements. The soil temperature is presented as the sum of diurnal and semi-diurnal fluctuations relative to daily average values. For solwing the problem we use improper integrals with a variable upper limit for the heat equation. This integral is calculated analytically. The results of the calculations on the formula are adequate to the available information on the heat transfer under natural conditions.