The borehole is a four-foot deep hole in our want soil. Using LM335 temperature sensors, a PICAXE is recording the temperature at one foot increments every hour. Here's what the data for March looks like.
|The temperature on the surface is strongly affected by the sun, even though the sensor head is covered worth a Styrofoam chest.|
|The diurnal temperature change one foot below the surface is only about 3 degrees Fahrenheit. We'll have to see how it changes over the course of a year.|
|At two feet and deeper, the temperature is warming up slightly after the hole allowed cold air to enter.|
|At three-feet deep, the temperature is warming up from the hole being dug during a cold day.|
|It appears the temperature four feet deep is recovering from the hole I dug in cold weather.|