Soil Temperature Exercises
- Consider
the temperature vs time graph. Note that the minimum temperature is zero
and the maximum is 30 °C as specified in the text windows above the graph.
The minimum temperature occurs at 10 days after the beginning of the year
(January 10). This is specified as the Time lag in the text box above. The
maximum temperature occurs near day 190. Complete the following table.
|
Depth (m)
|
Maximum
Temperature(°C)
|
Day of Maximum
|
Minimum
Temperature(°C)
|
Day of Minimum
|
|
0
|
30
|
190
|
0
|
10
|
|
1
|
|
|
|
|
|
2
|
|
|
|
|
|
3
|
|
|
|
|
|
4
|
|
|
|
|
|
5
|
|
|
|
|
|
10
|
|
|
|
|
- What
is the thermal diffusivity of a soil? What soil properties influence the
thermal diffusivity of a soil? How does its value affect the shape and
amplitude of the temperature vs time curves?
- Consider the temperature versus depth
graph.
- On
January 1, what is the maximum temperature in the profile? At what depth
does it occur? What is the minimum temperature in the profile? At what
depth does it occur?
- Describe
the temperature vs depth curves for the first day of each month of the
year.
- How
do the temperature vs depth curves change when the diffusivity changes?
- The
water content of a soil can change the thermal diffusivity from
approximately 0.05 to 0.08 m2 day-1. Does a
difference of this magnitude have a major impact upon the temperature vs
time or temperature vs depth curves?