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| Titel |
A new approach of surface flux measurements using DTS |
| VerfasserIn |
T. H. M. van Emmerik, K. J. R. Wenker, A. Rimmer, S. A. P. de Jong, Y. Lechinsky, N. C. van de Giesen |
| 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 |
250062027
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| Zusammenfassung |
| Estimation of surface fluxes is a difficult task, especially over lakes. Determining latent heat
flux (evaporation), sensible heat flux and ground heat flux involves measurements and (or
calculations) of net radiation, air temperature, water temperature, wind speed and
relative humidity. This research presents a new method to measure surface fluxes by
means of Distributed Temperature Sensing (DTS). From 0.5 m above lake level to
1.5 m under lake level DTS was applied to measure temperature. Using a PVC
hyperboloid construction, a floating standalone measuring device was developed. This
new setup distinguished itself by the open construction, so it is almost insensitive
to direct radiation. While most of the lake ground heat changes occur very close
to the lake surface, most measuring methods only obtain rough results. With this
construction it was possible to create a spiral shaped fiber-optic cable setup, with
which a vertical spatial resolution of 0.02 m and a temporal resolution of 1 min was
obtained. The new method was tested in the deep Lake Kinneret (Israel) from 6
October, 2011 to 11 October, 2011and in the shallow Lake Binaba (Ghana) from 24
October, 2011 to 28 October, 2011. This study shows that with the developed method
it is possible to capture the energy fluxes within the top water layer with a high
resolution. When the old low resolution method was compared with the new high
resolution method, it could be concluded that the impact of the surface fluxes in the
upper layer is high on the energy balance on a daily scale. During the measuring
period it was possible to use the temperature measured by the DTS to determine
the sensible heat flux, the latent heat flux and the ground heat flux of both lakes. |
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