Field comparison of four piezoelectric sensors for detecting aeolian sediment transport

Piezoelectric sediment transport sensors (PSTSs) are commonly used to detect aeolian sediment transport. Detection of particles in the near-surface airstream can be used to derive measures of sediment transport threshold, which is an important parameter in sediment transport modeling. However, despite common usage, little comparative field data regarding the detection capabilities of PSTSs are available. This study compares the sediment transport detection of four PSTSs: Sensit H11-B, Sensit H11-LIN (10× configuration), Safire, and Sensit H11-LIN (1× configuration). These sensors were co-located on an active sand dune for 11 days with data measured and recorded at 1 Hz. During this period the relative proportion of time that sediment transport occurred was as follows: Sensit H11-B: 7.212%, Sensit H11-LIN 10×: 3.260%, Safire: 1.832% and, Sensit H11-LIN 1×: 0.089%. These relative differences demonstrate that the transport detection capabilities of the sensors are inconsistent. We find that the cylindrical design and variable sensitivities restrict straightforward prediction of field detection according to sensor specifications. From these data we demonstrate that the response of each sensor influences the estimate of sediment transport threshold. Regardless of the source of variability, the very presence of detection inconsistency is problematic. Overall, results from this investigation indicate that comparison of metrics derived from measures of sediment transport presence/absence (such as threshold) with different PSTSs is, at present, tenuous.