Diploma thesis in Physics submitted by Florian Freundt born in ...

5.2. Temperature profiles 5 Results
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Figure 5.1: Temperature measurements taken at Site B at 0.1 m, 1.0 m and 2.5 m depth
and sinusoidal fits. Depth placement accuracy is ±0.1 m, temperature accuracy is ±0.5 ◦ C.
The atmospheric daily mean temperatures were provided by meteomedia, measured by a
weather station close to Site A.
The damping of the atmospheric temperature signal is clearly visible and increasing in magnitude
with depth. The insulating effect of snow cover is apparent during December and January,
leading to nearly constant temperatures above zero at 0.1 m depth while atmospheric temperature
above ground was well below 0 ◦ C. Neither sampling site experienced ground frost at 0.1 m
depth and lower during the Winter 2010/2011.
Comparison of the minima of the sinusoidal fits of the temperature curves (excluding known
erroneous readings) show the retardation of temperature penetration into the soil. At 0.1 m
the retardation is about ten days, at 1.0 m it is one month and two months at 2.5 m. The
atmospheric average temperature based on the fit (to account for gaps in the datasets) of the
meteomedia data from August 2010 to May 2011 was (12.5 ± 0.5) ◦ C. At Site A, the average
temperatures in the same time frame were: (10.8 ± 0.5) ◦ C at 0.1 m, (11.7 ± 0.5) ◦ C at 1.0 m and
(13.1 ± 0.5) ◦ C at 2.5 m. At Site B they were: (11.0 ± 0.5) ◦ C at 0.1 m, (12.2 ± 0.5) ◦ C at 1.0 m
and (12.4 ± 0.5) ◦ C at 2.5 m. Accuracy is based on the sensor’s accuracy.
During the irrigation of Site A the temperature measurements at 1.0 m and 2.5 m show spikes
coinciding with the water intrusion 1 (see Figure 6.1). Whether these spikes represent accurate
1 The lack of reaction to the first irrigation is due to the loggers recording at hourly intervals at that time,
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