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Validation of exposure time for discharge measurements made with two bottom-tracking acoustic doppler current profilers

By:
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DOI: 10.1109/CCM.2008.4480876

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Abstract

Previous work by Oberg and Mueller of the U.S. Geological Survey in 2007 concluded that exposure time (total time spent sampling the flow) is a critical factor in reducing measurement uncertainty. In a subsequent paper, Oberg and Mueller validated these conclusions using one set of data to show that the effect of exposure time on the uncertainty of the measured discharge is independent of stream width, depth, and range of boat speeds. Analysis of eight StreamPro acoustic Doppler current profiler (ADCP) measurements indicate that they fall within and show a similar trend to the Rio Grande ADCP data previously reported. Four special validation measurements were made for the purpose of verifying the conclusions of Oberg and Mueller regarding exposure time for Rio Grande and StreamPro ADCPs. Analysis of these measurements confirms that exposure time is a critical factor in reducing measurement uncertainty and is independent of stream width, depth, and range of boat speeds. Furthermore, it appears that the relation between measured discharge uncertainty and exposure time is similar for both Rio Grande and StreamPro ADCPs. These results are applicable to ADCPs that make use of broadband technology using bottom-tracking to obtain the boat velocity. Based on this work, a minimum of two transects should be collected with an exposure time for all transects greater than or equal to 720 seconds in order to achieve an uncertainty of ??5 percent when using bottom-tracking ADCPs. ?? 2008 IEEE.

Additional Publication Details

Publication type:
Conference Paper
Publication Subtype:
Conference Paper
Title:
Validation of exposure time for discharge measurements made with two bottom-tracking acoustic doppler current profilers
ISBN:
1424414865; 9781424414864
DOI:
10.1109/CCM.2008.4480876
Year Published:
2008
Language:
English
Larger Work Title:
Proceedings of the IEEE Working Conference on Current Measurement Technology
First page:
250
Last page:
257
Number of Pages:
8
Conference Title:
IEEE/OES/CMTC 9th Working Conference on Current Measurement Technology
Conference Location:
Charleston, SC
Conference Date:
17 March 2008 through 19 March 2008