The direction of the wind, that is, the direction in which the wind blows, is expressed in terms of orientation or angle. In the weather forecast, we often heard such words: Tonight, tomorrow, southerly wind, 4-5. This southerly wind is the wind direction, and 4-5 is the wind speed. The word "bias" means that the swinging of the azimuth cannot be determined. The north wind that is commonly referred to is the wind blowing from the north, and the south wind is the wind blowing from the south. This is only a rough idea. It is not the wind that blows north or south. The wind speed we usually say is generally 13 levels. Specifically, we will explain it in detail below.
The expression of the wind direction can be used as the word bearing. Generally, we divide it into 16 positions: north wind, south wind, southeast wind, northwest wind, northeast wind and so on. See the figure below.
Figure Wind direction 16 positions
When we use the angle to express the wind direction, we say that the north wind is 0 degrees, the south wind is 180 degrees, the southeast wind is 135 degrees, and so on. We also have a concept of wind direction frequency, which is the frequency of winds that represent a certain direction. The formula is: wind direction frequency = total number of observations of wind direction/wind direction*100%. Through the wind direction, we can know in which direction an area has more wind, and which direction has less wind.
The wind speed, in academia, we are divided into 12 levels, as shown in the table below.
Table wind level table
Wind level symbol
name
Wind speed (m/s)
Land objects
Sea waves
Wave height (m)
0
No wind
0.0-0.2
Smoke straight up
calm
0.0
1
light air
0.3-1.5
Smoke direction
Microwave peak without droplets
0.1
2
Light wind
1.6-3.3
Feeling windy
Wavelet peaks are not broken
0.2
3
breeze
3.4-5.4
Flag expansion
Wavelet peak rupture
0.6
4
Wind
5.5-7.9
Blow up dust
Xiaolang Baimo Crest
1.0
5
Strong wind
8.0-10.7
Small tree swing
Zhonglang Mofeng Group
2.0
6
Gale
10.8-13.8
Wire sound
Big wave to a spray
3.0
7
blast
13.9-17.1
Difficulty walking
Peak breaking foam
4.0
8
Strong wind
17.2-20.7
Broken tree branches
Long wave high spray
5.5
9
Gale
20.8-24.4
Small loss house
Wave rewind
7.0
10
Wind
24.5-28.4
Pull up the trees
Waves tumbling roar
9.0
11
storm
28.5-32.6
General damage
The peak is full of droplets
11.5
12
hurricane
32.7-
Destroy huge
Waves
14.0
Note: The wind speed listed in this table refers to the wind speed at 10 meters above the ground on the flat ground.
In fact, in the natural world, there are more than 12 levels of wind power, such as the wind power of strong typhoon centers, wind power of tornadoes and so on, which is more than 12 levels. However, this is generally difficult to measure and is not common, so it is generally no longer specifically graded.
Today, there are portable wind anemometers or wind direction wind detectors that can quickly detect 0-360. And 0-40m/s wind speed. This portable wind anemometer model TPJ-30, which can continuously record 30,000 information, while measuring the accuracy of wind speed of ± 0.6m / s, resolution: 0.1m / s; measuring wind direction accuracy: ± 0.6 degrees , Resolution: 0.1 degrees. Specific can see
Wind anemometer
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