Heavy rain and strong wind

During strong storms, water can splash off of the horizontal bottom plate of the anemometer envelope and interrupt the signal passing between the sonic transducers. The spikes on the bottom plate help dissipate the rainwater to minimize splashing and reduce the likelihood that the wind measurements are interrupted. Additionally, porous polyethylene membranes protect the ultrasonic transducers from direct splashing and the sintered (porous) glass construction draws water from the upper surface of the acoustic mirror to keep a constant sound path length. Despite these features, heavy rain and strong winds can cause water to reach the membranes and also cause temporary water buildup on the acoustic mirror. The hydrophobic nature of the transducer protective membranes and the quick-draining ability of the acoustic mirror should limit wind measurement interruptions to heavy rain and should bring wind measurement back online soon after extreme conditions abate.