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

C Additional plots and figures
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Figure C.8: Temperature measurements taken at Site A 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 offset visible at 1.0 m depth in August 2010 is caused
by a moisture intrusion into the sensor in August 2010 after refilling the borehole with
sludge. Comparison with the data from Site B leads to the conclusion that the sensor was
affected by this until early October 2010. The smaller offset at 2.5 m depth in December 2010
and January 2011 coincide with heavy precipitation (Figure C.10). The low atmospheric
temperatures at the time indicate that this also is an offset caused by moisture intrusion
rather than an actual temperature change by infiltrating rain water of different temperature.
Such an event is visible in May 2011, when cold tap water was used for irrigation, leading to
spikes in the temperature curves of 1.0 m and 2.5 m. The sensor at 0.1 m depth was shielded
against these sudden and short-lived temperature changes by being insulated by air inside
the instrumentation box.
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