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Active heat pulse sensing of 3-D-flow fields in streambeds
Ist Teil von
Hydrology and earth system sciences, 2018-03, Vol.22 (3), p.1917-1929
Ort / Verlag
Katlenburg-Lindau: Copernicus GmbH
Erscheinungsjahr
2018
Quelle
EZB Electronic Journals Library
Beschreibungen/Notizen
Profiles of temperature time series are commonly used to determine hyporheic
flow patterns and hydraulic dynamics in the streambed
sediments. Although hyporheic flows are 3-D, past research has focused on determining the magnitude of the vertical flow component
and how this varies spatially. This study used a portable 56-sensor, 3-D temperature array with three heat pulse sources to measure the
flow direction and magnitude up to 200 mm below the water–sediment interface. Short, 1 min heat pulses were injected at
one of the three heat sources and the temperature response was monitored over a period of 30 min. Breakthrough curves from each of
the sensors were analysed using a heat transport equation. Parameter estimation and uncertainty analysis was undertaken using the
differential evolution adaptive metropolis (DREAM) algorithm, an adaption of the Markov chain Monte Carlo method, to estimate the flux and its orientation. Measurements were
conducted in the field and in a sand tank under an extensive range of controlled hydraulic conditions to validate the method. The use
of short-duration heat pulses provided a rapid, accurate assessment technique for determining dynamic and multi-directional flow
patterns in the hyporheic zone and is a basis for improved understanding of biogeochemical processes at the water–streambed
interface.