Interaction of the atmosphere with underlying surfaces

within which temperature experiences diurnal and annual variations. The processes

developing in this layer and those in laying above atmosphere are closely interrelated.

The active layer (especially that of the ocean) can greatly influence the heat budget of the atmosphere.

at P=const is 4 times smaller than that of water.

Therefore, the ocean input into vertical column heat content is 120 times larger than that of the atmosphere.

In turn, ocean reacts on the wind causing waves and currents.

Air flows (wind)

Waves and currents

Structure of air flows

depth of the soil due to molecular heat conductivity.
Soil heat

conductivity equation

is soil heat conductivity coefficient

The soil heat conductivity is 100 times larger than the molecular heat conductivity of the air

filled with air. Therefore, as the porosity increases, the heat

conductivity decreases.
Porosity is defined as the ratio . Here va is a volume occupied by the air in the total volume of the soil vs.
When watering soil, its heat conductivity increases because the air in it is replaced by the water. Heat conductivity of the water is 20 times bigger of that of the air.

Since composition and moisture of the soil may vary with depth and time, the soil heat conductivity (SHC) is also variable parameter depending on its moisture, porosity, and composition.

The heat influx to a unit of soil mass can be described as:

Soil density

specific heat capacity
Thus, with respect to a unit of mass

and a unit of time the equation of soil heat conductivity (soil energy equation) will be:

or

The product is the soil volume heat capacity (SVHC).
For average conditions SVHC=ρ*C*=2.09 J/cm³K. That is about a half of the water heat capacity, air heat capacity order of magnitude is

In case of homogeneous soil, all coefficients in the equation will be constant.

Coefficient of soil temperature conductivity
Fourier’s equation

responsible for the heat (temperature) regime of the body.
Formulas to

calculate the net heat influx are known as heat budget equations. These formulas can be drown for earth’s surface, for the atmosphere, for the earth as a planet etc.
Earth’s surface

Earth’s surface heat budget

In the soil all these fluxes suffer some variation. For an elementary layer the variation will be:

Elementary layer

Coefficient of absorption

Heat flux

eddy exchange, i. e. the soil looses some heat.
Evaporation of

water from the soil also result in some losses of heat from the soil.

The depth the flux Ф(0) passing through decreases in “e” times.

Flux of latent heat

Heat flux trough the lower boundary of the layer ∆

Under impact of all fluxes the soil temperature experiences variation, and ice (snow) melts or water freezes

a vertical soil column with the depth ∆
Income part
Outgoing part
Resulting

sum of these fluxes will cause:

Heat content of the layer ∆ growth up or down depending on the sign of the sum and melting snow or/and ice (if any) or freezing water.

instance, let’s take a very thin layer ∆ with no

snow (ice) on it. In this case the last term is equal to 0. The term before it is very small since the layer ∆ is very thin. The term can be neglected.

Radiation budget of the surface

presented in form of trigonometric expansion.
Using two terms only,
Amplitude of

radiation budget diurnal variation

Time of max. R value

soil is very moist.
In the case (a)
In the case

(b):

For 24 h

At

the moist surface

soil temperature diurnal variation is proportional to the amplitude of

the radiation budget diurnal variation.
Amplitude of the soil temperature variation decreases as eddy coefficient increases, soil temperature conductivity coefficient Km increases, and soil volume heat capacity c*ρ* increases.
Significant impact on the surface temperature variation is made by the soil moisture.

amplitude (more than 3 times)
4. The value Π/8 suggests that

maximal temperature occurs 3 hours later than .

That is all! Good luck!