Design and field test of a continuously weighing, tipping-bucket assembly for aeolian sand traps
✍ Scribed by Bauer, Bernard O.; Namikas, Steven L.
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 247 KB
- Volume
- 23
- Category
- Article
- ISSN
- 0360-1269
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✦ Synopsis
A new tipping-bucket assembly (T-BASS) for aeolian sand traps has been designed and field tested with encouraging results. It facilitates high-frequency monitoring of sediment flux over extensive time periods, and therefore offers improved performance over other continuously weighing mechanisms that are generally limited to either a small total-load capacity or poor resolving ability. The T-BASS is a modified version of the tipping-bucket meteorological rain gauge mounted on a cantilever and pulley system linked to an electronic load cell. As trapped sand accumulates in one of the buckets, the increasing mass exerts a downward force on the cantilever arm, which translates into a slight deflection of the thin-beam element of the load cell. The resulting voltage output is proportional to the load, and the analogue signal may be monitored by a data-acquisition system. Eventually the bucket fills to capacity and tips, the sediment load is emptied into a reservoir container, the other bucket of the bucket pair is positioned beneath the funnel, and the system is automatically reset to zero load for continued measurement. In this way, a high-frequency record of sediment accumulation is obtained.
Field testing of five prototypes demonstrated that the T-BASS can be configured to yield: (i) linear calibrations (for conversion of voltage to gram weight) with R 2 values exceeding 0•99; (ii) weight resolution of 0•1g or better depending on load-cell specifications and bucket capacity; and (iii) detailed temporal information (order of 1s) on sediment flux allowing investigation of its relation to attributes of the wind field. Suggested modifications may produce improved performance in future versions.