Wind direction refers to the direction of the wind or something.

Wind direction refers to the direction of the wind, which is introduced as follows:

Wind direction refers to the direction in which the wind blows.

Meteorology determines the wind direction as the wind direction. Therefore, the wind from the north is called the north wind and the wind from the south is called the south wind. Wind direction is often expressed in eight or sixteen directions.

China generally uses eight directions to predict the wind direction. For example, the wind blowing between 337.5 and 22.5 is called the north wind, and the wind blowing between 22.5 and 67.5 is called the northeast wind.

When making large-scale weather forecast, we sometimes hear the names of north wind and west wind. At this time, the wind direction shows four directions. At this time, the wind blowing between 3 15-45 indicates northerly wind; The wind blowing between 45- 135 is called easterly wind; The wind blowing between 135-225 is called southerly wind, and the wind blowing between 225-3 15 is called westerly wind.

When the meteorological station forecasts the wind, the wind direction swings from side to side in a certain direction. When it is uncertain, the word "bias" is used, such as northerly wind. When the wind is very small, it is explained by "uncertain wind direction"

Wind direction measurement

One of the instruments for measuring the wind direction is the wind vane, which is generally10-12m above the ground. If there is an obstacle nearby, its height should be at least 6 meters higher than the obstacle, and the short stick pointing north should face north. In which direction the wind arrow points, it means what direction the wind direction is at that time.

There is also a rectangular wind pressure plate (800g in weight and 200g in weight) on the anemometer, and an arc frame with long and short teeth is installed next to the wind pressure plate. The number of long and short teeth that the wind pressure plate passes through indicates the wind force.

Wind vane is one of the most widely used wind direction measuring devices, including single wing type, double wing type and streamlined type. Wind vane is generally an asymmetric balancing device, which consists of four parts: tail wing, pointing rod, balancer and rotating spindle. Its center of gravity is on the axis of the supporting shaft, and the whole wind vane can swing freely around the vertical axis.

When the blade is at a certain angle to the direction of air flow, the air flow produces a pressure f at the tail of the blade. Its size is in direct proportion to the projection of the geometric shape of the wind vane on the vertical plane in the air flow direction. The windward area of the wind vane head is small and the windward area of the tail is large. The wind pressure moment is generated by the component f of the pressure difference in the direction perpendicular to the wind vane, so that the wind vane rotates around the vertical axis until the wind vane is parallel to the airflow. The wind direction can be easily observed from the relative position between the wind vane and the fixed main azimuth indicator.