Meteorological wind direction refers to

Meteorological wind direction refers to the direction of the wind.

Wind direction refers to the direction in which the wind blows. Generally, there are different determination methods. Mainly divided into oceans, continents and high altitudes. Wind direction can play an active role in people's life, production, factory buildings, agriculture, transportation, military and other fields.

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 the "wind direction uncertainty" of the wind speed limit when the instrument is started. The wind with the wind speed less than 2m/s is usually recorded as no wind, that is, the wind direction is missing.

The unit of measurement of wind direction, which we express in azimuth. For example, on land, it is generally represented by 16 directions, and at sea, it is represented by 36 directions. At high altitude, it is expressed by angle. To express the wind direction by angle means to divide the circumference into 360 degrees, the north wind (n) is 0 degrees (that is, 360 degrees), the east wind (e) is 90 degrees, the south wind (s) is 180 degrees, and the west wind (w) is 270 degrees, and the rest wind directions can be calculated from this. As shown in figure 1.

In order to express the wind frequency in a certain direction, it is usually expressed by the wind direction frequency, which refers to the percentage of the wind frequency in a certain direction to the total frequency of all winds in a year (month), that is, wind direction change = wind direction frequency/wind direction total observation frequency × 100%.