The wind rose diagram is a statistical graph that represents the airflow repetition rate in all directions in the form of "roses". The data used can be within one month or one year, but the average statistical data of a region for many years is usually used, and its types are generally wind direction rose chart and wind speed rose chart.
Wind direction rose chart, also known as wind frequency chart, is a closed line chart that divides the wind direction into eight directions or 16 directions, intercepts the corresponding length on each direction line according to the wind frequency in each direction, and connects the cutting points on adjacent direction lines with straight lines (as shown in figure 1). In Figure 1, the wind direction with the maximum wind frequency in this area is the north wind, which is about 20% (each interval represents 5% of the wind direction frequency);
The number in the middle circle represents the frequency of still wind.
If the average wind speed in all directions is expressed in this way, it becomes a rose diagram of wind speed.
There are other forms of wind rose diagram, as shown in Figure 2 ~ Figure 5, in which Figure 3 is a rose diagram of wind frequency and wind speed, and each direction reflects both the wind frequency (the length of the line segment) and the average wind speed in that direction (the number of wind feathers at the end of the line segment); Figure 4-5 is a simplified diagram of the wind rose diagram without quantification, and the length of the line segment indicates the relative magnitude of the wind frequency.
In short, which direction is long means which direction has high incoming wind frequency.
Extended data:
The wind rose map is an important part of public meteorological service, which plays an important role in building planning, environmental protection, wind power generation, fire protection, oil station design, marine climate analysis and other fields.
1, urban planning
Air pollutants produced by industrial enterprises are mainly diluted and diffused by gas movement. The frequency of wind direction indicates the number of blows in a certain wind direction and shows the pollution opportunity in the downstream area of a certain wind direction. Downstream areas with high frequency have more pollution opportunities, and vice versa. Therefore, industries with waste gas pollution are usually arranged on the side of the minimum wind frequency in the wind rose diagram; ?
Wind speed determines the diffusion speed of pollutants. The greater the speed, the longer the waste gas discharged from the factory, the more air mixed in, and the smaller the concentration of pollutants. On the contrary, the lower the speed, the greater the concentration of pollutants, so industries with waste gas pollution should be arranged in the direction of high wind speed.
The wind rose map reflects the important information of meteorological element wind. Based on this information, wind pollution theory can effectively guide urban planning and industrial layout, and can also be used to analyze the rationality of urban land use.
2. Environmental protection
Air pollutants are diluted by wind diffusion, so evaluating the impact of a pollution source on the surrounding environment or evaluating the pollution situation in a certain place is related to the local wind conditions.
The wind rose diagram is more vivid and intuitive, and the pollution probability rose diagram and pollution coefficient rose diagram are derived, which are widely used in pollution meteorology and air pollution evaluation.
3. Wind power generation
Wind Rose Diagram is an essential step in the early stage of wind farm construction-the main tool of "wind energy resource assessment".
4. Fire fighting
The wind rose diagram is an indispensable tool for the fire supervision department to carry out construction and audit work according to the relevant national fire technical specifications, which is generally provided by the local meteorological department.
Baidu Encyclopedia-Wind Rose Map