We consider the behavior of numerical solutions obtained using simple photochemical model of the surface atmosphere that assumes uniform distribution of the components over the mixing layer. The mean ozone entrainment flux from above into the mixing layer is determined. These entrainment flux values are required for reaching the equality between the average ozone concentrations in the beginning of the calculated diurnal period and in its end. The diurnal variation of the surface ozone experimentally observed at the high-latitude observatory in Lovozero (Murmansk Region) is discussed and it is shown that the average surface ozone concentrations at 0 a.m. and 24 p.m. (local time) are equal to each other within the accuracy of tenths of ppb. Comparison is made of the calculated ozone entrainment flux with the experimental data on the ozone flux from the stratosphere to the troposphere at the tropopause in different seasons. It has been found that if the total value of the ozone entrainment flux at mid-latitudes is equal approximately to 5 x 1010-1,2 x 1011 см-2x с-1, then at high latitudes this value is assumed to be considerably higher in the model discussed here.