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首页> 外文期刊>Journal of hydrometeorology >Snow Particle Collection Efficiency and Adjustment Curves for the Hotplate Precipitation Gauge
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Snow Particle Collection Efficiency and Adjustment Curves for the Hotplate Precipitation Gauge

机译：用于加热板沉淀计的雪粒子收集效率和调整曲线

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The hotplate precipitation gauge operates by means of a thermodynamic principle. It is composed of a small disk with two thin aluminum heated plates on the upper and lower faces. Each plate has three concentric rings to prevent the hydrometeors from sliding off in strong wind. As for the more widely used tipping-bucket and weighing gauges, measurements are affected by the wind-induced bias due to the bluff-body aerodynamics of the instrument outer shape. Unsteady Reynolds-averaged Navier-Stokes equations were numerically solved, using a k-omega shear stress transport closure model, to simulate the aerodynamic influence of the gauge body on the airflow. Wind tunnel tests were conducted to validate simulation results. Solid particle trajectories were modeled using a Lagrangian particle tracking model to evaluate the influence of the airflow modification on the ability of the instrument to collect the incoming hydrometeors. A suitable parameterization of the particle size distribution, as a function of the snowfall intensity, was employed to calculate the collection efficiency (CE) under different wind conditions. Results reveal a relevant role of the three rings in enhancing the collection performance of the gauge. Below 7.5 m s(-1), the CE curves linearly decrease with increasing the wind speed, while beyond that threshold, the blocking caused by the rings counter effects the aerodynamic induced undercatch, and the CE curves quadratically increase with the wind speed. At high wind speed, the undercatch vanishes and the instrument exhibits a rapidly increasing overcatch. For operational purposes, adjustment curves were formulated as a function of the wind speed and the measured snowfall intensity.
机译：热板式雨量计根据热力学原理工作。它由一个小圆盘组成，在上下表面上有两个薄的铝加热板。每个平板都有三个同心环，以防止比重计在强风中滑落。至于更广泛使用的翻斗和称重仪表，由于仪表外部形状的钝体空气动力学，测量受到风致偏差的影响。采用k-omega剪切应力输运闭合模型，数值求解了非定常雷诺平均Navier-Stokes方程，模拟了规体对气流的气动影响。为了验证模拟结果，进行了风洞试验。使用拉格朗日粒子跟踪模型对固体粒子轨迹进行建模，以评估气流修正对仪器收集进入的液体比重计能力的影响。采用合适的粒径分布参数，作为降雪强度的函数，计算了不同风力条件下的收集效率（CE）。结果表明，三个环在提高压力计收集性能方面发挥了相关作用。在7.5 m s（-1）以下，CE曲线随风速的增加而线性减小，而超过该阈值时，由环引起的阻塞会抵消气动诱导的捕获不足，CE曲线随风速的平方增加。在高风速下，欠捕获消失，仪器显示出快速增加的覆盖。出于操作目的，调整曲线是风速和实测降雪强度的函数。

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