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| Titel |
Temperature Fluctuations underneath the Ice in Diamond Lake, Minnesota |
| VerfasserIn |
G. Kletetschka, T. Fischer, J. Mls |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250065839
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| Zusammenfassung |
| Autonomous temperature sensors, data loggers, were placed in the Diamond
Lake in Minnesota, Minneapolis, USA. Hourly measurements have been obtained
from the snow-covered ice frozen over the shallow lake and as well as from
the water directly under the ice. The sensors that were frozen within the
ice showed dumped and delayed thermal fluctuation from the surface. The
sensors that were deeper within the ice showed continuous, almost constant,
temperature near the freezing. All of the sensors that were within the
liquid water below the ice showed a thermal variation with 12 but mostly 24
hour periods of amplitudes up to 0.2°C. The analysis of the vertical
temperature profile shows that the source of periodic water heating is
located below the lake bottom. The absence of daily temperature variations
of the ice cover rules out the possible influence of the air temperature.
We attribute the heating process to the periodic inflow of ground water to
the lake and the cooling to the heat diffusion to the overlying ice cover.
The periodic ground water inflow is explainable by solid Earth tides, which
cause periodic fluctuations of the ground water pressure head. |
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