Investigation of measurement characteristics of different types of Anemometers

When crosswinds are too strong, it is necessary to refrain from operating trains and trucks in order to avoid accidents. Since the wind direction and the wind speeds are the two important indicators of the danger, anemometers are installed in various places from urban to mountainous areas. The wind speed is greatly influenced by the surrounding environment, thus Japanese Meteorological Agency recommends that the anemometer should be set sufficiently far from buildings and installed at the top of the column. However, depending on the conditions of the installation site, sometimes it is inevitable to attach the anemometer to a support extended in the horizontal direction from the middle of the column. In that case, the measurement value is disturbed when the wind comes from the direction of the column. In order to investigate the influence of the support on the measurement, the wind speeds up to 20 m/s were measured with several anemometers which adopt different measurement methods such as cup and ultrasonic.