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首页> 外文期刊>Earth Surface Processes and Landforms: The journal of the British Geomorphological Research Group >High resolution sensors in space and time for determination saltation and creep intensity
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High resolution sensors in space and time for determination saltation and creep intensity

机译：时空高分辨率传感器，用于确定盐分和蠕变强度

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The measurement of aeolian sand transport rates at high temporal and spatial resolution is crucial for further progress in testing and developing numerical models of sand movement by wind and in the modelling of sand dunes, ripples and so on. This paper reports the development and field testing of two sand transport sensors. The first one, a webcam commonly used with personal computers, is a new device in aeolian research. The webcam frame transfer is triggered by a sonic anemometer every 0·1 second. Consecutive frames are compared and analysed in real-time by a computer program. Changes in pixel light intensity exceeding a threshold level are recorded and interpreted as grain movements. The second sensor is a small-sized 'Saltiphone'-type device made of simple loudspeakers with a diameter of 15mm as used in MP3 players. It can be deployed as a 2×3 array of six such devices distributed to enable horizontal and vertical spatial sampling of the sand flux. The devices are tested under field conditions. Both signals and the sum of microphone impacts over 15 minutes are compared to data gathered using a Guelph sand trap, and very good agreement is found. Measurements in a wind tunnel using sieved natural sand indicate that the webcam can be used to infer additional information about the grain size. As an application, the fluid and impact thresholds for aeolian sand transport are investigated in field measurements by analysing the onset and breakdown of saltation in gust and lull intervals of rising and falling wind speeds, respectively. In this way, constitutive equations for sand transport in terms of the wind speed can be tested. If viable, they can be employed to infer estimates for the thresholds by minimizing the root-mean-square error between measured and calculated transport data.
机译：在高时空分辨率下测量风沙运移速率，对于测试和开发风沙运动数值模型以及沙丘，涟漪等建模的进一步进展至关重要。本文报告了两个输沙传感器的开发和现场测试。第一个是个人计算机常用的网络摄像头，是风沙研究中的一种新设备。网络摄像头帧传输是由声音风速计每0·1秒触发一次。连续帧通过计算机程序进行实时比较和分析。记录超过阈值水平的像素光强度的变化，并将其解释为颗粒运动。第二个传感器是小型的“ Saltiphone”型设备，由简单的扬声器制成，直径为15mm，用于MP3播放器。可以将其部署为6个此类设备的2×3阵列，以实现水平和垂直空间砂通量的采样。该设备在现场条件下进行了测试。将15分钟内的信号和麦克风撞击的总和与使用Guelph沙井收集的数据进行比较，发现非常吻合。使用筛分的天然沙子在风洞中进行的测量表明，网络摄像头可用于推断有关晶粒尺寸的其他信息。作为一种应用，通过在风速上升和下降间隔的阵风和平静间隔内分别分析盐分的发生和破裂，在野外测量中研究了风沙输送的流体和冲击阈值。以此方式，可以测试根据风速进行沙粒运输的本构方程。如果可行的话，可以通过最小化测量和计算的运输数据之间的均方根误差来推断阈值。

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