Observations of wind‐blown sand under various meteorological conditions at a beach

Abstract

[1] Field observations were conducted on a natural, open ocean beach system in Japan to investigate characteristics of wind-blown sand transport under various weather conditions including a storm event. Data sets over periods of several hours included blown sand impact counts, three-dimensional wind conditions, hourly precipitation, and moisture content of the sediment surface. The intermittent blown sand impact data shifted by 1 s ahead of the wind velocity correlated with the wind velocity during a no-rainfall period (for an assumed dry surface) and in the longshore wind direction (for sufficiently long fetch length). The 5-min mean wind velocity/impact counts relationship was well constrained by both second-and third-order polynomial fitting of velocity under similar weather conditions. During a no-rainfall period and in the longshore wind direction, the relationship between the wind velocity and sand flux estimated from the counts coincides with existing studies in wind tunnel experiments. The sand flux, however, decreased by 1 order of magnitude because of a change in the wind direction from longshore to cross-shore and then by more than 1 order of magnitude because of an increase in the moisture content. Threshold wind velocity calculated using the time fraction equivalence method with the impact counts and the horizontal wind velocity in 5-min sampling periods was approximately equal to the value predicted using Bagnold's equation during the no-rainfall period and increased significantly during the rainfall phase. The sand flux sensor has several limitations for complex conditions in the field; however, it provides a number of characteristics of sand transport under various meteorological conditions.

Comparison of four methods to calculate aeolian sediment transport threshold from field data: Implications for transport prediction and discussion of method evolution

“…Wiggs et al (2004a) furthered this research and examined the impact of modifying both sampling and measurement intervals. Baas (2004), Van Pelt et al (2009), and Barchyn and Hugenholtz (2010) compared electronic sediment transport sensors and found inconsistencies in response between manufacturers, sensors, and around the circumference of individual sensors. In general, most work has found that modifying the aspects of the measurement system can affect the threshold values produced.…”

“…We collected high resolution wind and sediment transport data (1 Hz) on an active sand (Stockton and Gillette, 1990;Stout and Zobeck, 1997;Van Pelt et al, 2009); Safire (Baas, 2004;Van Pelt et al, 2009); Balance trap (Davidson-Arnott et al, 2005;Nickling and McKenna Neuman, 1997); UD-101 (Udo, 2009); Saltiphone (Spaan and van den Abeele, 1991;Van Pelt et al, 2009). b We assume that the Saltiphone used is identical dimensions to that of the sensor described in Spaan and Van den Abeele (1991).…”

Field Measurement of Aeolian Sand Flux Using Ceramic Sand Flux Sensor Ud-101 at a Sand Dune

“…Significant difference between the UD-101 and the others is that the UD-101 is unidirectional while both the Sensit and Safires are omnidirectional. The UD-101 should be placed in the same direction as the mean wind direction in the field; however, it has an advantage of counting only blown sand from the upwind side (Udo et al 2008). The sensor used in this study had a diameter of 0.012 m and a length of 0.20 m. The logger recorded the maximum 10,000 counts data at an interval of 1 s. The wind velocity and direction were measured at heights of z = 0.3 m and 1.0 m using threecup anemometers.…”

“…Udo et al (2008) carried out short-term field observations using UD-101 for several days in winter at the Hasaki Beach in Japan and demonstrated features of instantaneous aeolian transport over a flat bed under various meteorological conditions. In addition, Udo (2009) conducted long-term observations of the instantaneous transport over nine months and investigated seasonal characteristics of the aeolian transport.…”

“…The first author has been investigated the aeolian sand transport in the field using a piezoelectric sensor UD-101 (Chuo Kosoku) which can count the number of wind-blown sand at a high-temporal resolution of 1 Hz at a height (Kubota et al , 2007Udo et al 2008). Udo et al (2008) carried out short-term field observations using UD-101 for several days in winter at the Hasaki Beach in Japan and demonstrated features of instantaneous aeolian transport over a flat bed under various meteorological conditions.…”