Snow Particle Collection Efficiency and Adjustment Curves for the Hotplate Precipitation Gauge

Abstract The hotplate precipitation gauge operates by means of a thermodynamic principle. It is composed small disk with two thin aluminum heated plates on the upper and lower faces. Each plate has three concentric rings to prevent hydrometeors from sliding off in strong wind. As for more widely used tipping-bucket weighing gauges, measurements are affected wind-induced bias due bluff-body aerodynamics instrument outer shape. Unsteady Reynolds-averaged Navier–Stokes equations were numerically solved, using k–ω shear stress transport closure model, simulate aerodynamic influence body airflow. Wind tunnel tests conducted validate simulation results. Solid particle trajectories modeled Lagrangian tracking model evaluate airflow modification ability collect incoming hydrometeors. A suitable parameterization size distribution, as function snowfall intensity, was employed calculate collection efficiency (CE) under different wind conditions. Results reveal relevant role enhancing performance gauge. Below 7.5 m s −1 , CE curves linearly decrease increasing speed, while beyond that threshold, blocking caused counter effects induced undercatch, quadratically increase speed. At high undercatch vanishes exhibits rapidly overcatch. For operational purposes, adjustment formulated speed measured intensity.