Wind level table Wind level High sea level Sea and fishing signs Land surface signs Comparable wind speed (m/s) general highest range Medium* - - calm Quiet smoke 0.0 to 0.2 0 0.1 0.1 Microwave Smoke can indicate wind direction, leaves slightly shaken 0.3 to 1.5 1 0.2 0.3 There is a small ripple, the boat shakes The human face feels windy, the leaves are slightly buzzing, the flag flutters, and the tall grass and crops start to shake 1.6 to 3.3 2 0.6 1.0 There is a small wave, the fishing boat feels incited The leaves and twigs are shaking, the flag is unfolding, and the tall grass and crops are shaking. 3.4 to 5.4 4 1.0 1.5 There is some white foam on the top of the waves. When the fishing boat is full, it can make the hull dump on one side. Can lift ground dust and paper, swing branches, high grass and crop undulations 5.5 to 7.9 7 2.0 2.5 There are more white foams on the top of the waves, and one of the fishing boats receives sails Leaves and twigs sway, inland waters have wavelets, high grass and crops undulate 8.0 to 10.7 9 6 3.0 4.0 White foam began to be blown away from the waves The branches sway, the wires screaming, the umbrellas difficult, the tall grass and crops swaying from time to time 10.8 to 13.8 12 4.0 5.5 White foam left the top of the sea and was blown into strips The whole tree shakes, the big branches bend down, and it's inconvenient to walk in the wind 13.9 to 17.1 16 5.5 7.5 The white foam is blown into a pronounced stripe Dismantling the twigs, people feel the resistance in front of the wind 17.2 to 20.7 19 7.0 10.0 Wind-blown waves reduce horizontal visibility, making sailing difficult The straw house was damaged, the roof tiles were lifted, and the big branches could be broken 20.8 to 24.4 twenty three 9.0 12.5 Wind-blown waves reduce horizontal visibility, making sailing dangerous Trees can be blown down and buildings are generally destroyed 24.5 to 28.4 26 11.5 16.0 The wind-blown spray significantly reduces horizontal visibility, and the ship is extremely dangerous Large trees can be blown, and buildings are severely damaged 28.5 to 32.6 31 14.0 - Waves Land is rare and its destruction is great >32.6 >31 In fact, wind power sometimes exceeds 12 levels in nature. The wind power of the strong typhoon center, or the wind power of a tornado, may be much larger than that of the 12th level, but the gale of over 12 levels is relatively rare, and it is generally not specified in the series. UPVC WPC Window Profile Door Panel Production Line UPVC Profile Machine,PVC Window Profile Machine,UPVC Profile Making Machine,PVC WPC Door Panel Machine WUXI HAOBANG MACHINERY MANUFACTURING CO.LTD , https://www.haobangmachinery.com
The wind speed is the speed of the wind. The greater the pressure difference between two adjacent places, the faster the air flows, and the greater the wind speed, the greater the power of the wind. So usually the wind is used to indicate the size of the wind. The unit of wind speed is expressed in meters per second or in kilometers per hour. When it comes to weather forecasts, most of them use wind power.
How is the series of wind power determined?
In the Tang Dynasty of China more than a thousand years ago, in addition to weather events such as sunny, rainy and snowy weather, people also measured the size of wind. At the beginning of the Tang dynasty, there was no precise instrument for measuring the wind speed, but at that time it was possible to calculate the wind speed and set the wind level based on the wind's symptoms on the object. In Li Fengfeng’s “Phenomenon of Playâ€, there is such a record: “The moving leaves are ten miles long, the bar is hundred miles, the two hundred miles are shaken, three hundred deciduous leaves, four hundred twigs are broken, five hundred jins are broken, and the stone is taken thousands of miles. , pulling roots 3,000 miles. "This is based on the effect of the wind on the tree to estimate the speed of the wind, "moving leaves ten miles" that leaves slightly fluttering, the speed of the wind is ten miles a day; "Ming" is the leaf rustle Ringing, the wind speed at this time is 100 miles a day. In addition, according to the tree's symptoms set out in some wind, such as "B already accounted for" said, "First-level moving leaves, two-level Ming, three-level branches, four falling leaves, five-fold branchlets , six-fold branch, seven-fold wood, fly sand, eight trees and roots. This eight-level wind, combined with “no wind†and “wind†(cool, mild, dusty, and windy), can be combined into ten levels. The level of these winds is comparable to that of foreign arrivals. This is arguably the earliest wind class in the world.
More than two hundred years ago, there were no instruments for measuring the size of the wind and there were no uniform regulations. All countries expressed their own methods. At that time, there was a British man called Beaufort. He carefully observed the situation of various objects in the land and sea in winds of different sizes. He accumulated 50 years of experience before he classified the wind in 13 levels in 1805. . Later, after research and supplement, the original explanation was explained more clearly, and the speed of each class of wind was added. Now, it became the “jargon†of forecasting wind power. In some places, the content of the wind level was also compiled into songs for memory:
Zero grade windless smoke; Grade one soft wind smoke slightly oblique;
Grade 2 light breeze leaves; three breeze branches;
Level 4 wind and dust rise; Level 5 breeze rises;
Six strong winds shook the tree; seven blasts were difficult;
Eight winds broken branches; nine gale chimney destroyed;
Grade ten winds are rooted; Eleventh storms are rare;
Twelve hurricane days.
The distance the wind moves within seconds - the wind speed, its verb is "from all the way to the nine, by 2 levels." Means: From the first level to the nine level winds, each level is multiplied by 2, and the maximum speed of the wind can be roughly obtained. For example, the maximum speed of the first-class wind is 2 meters per second, the second-level wind is 4 meters per second, the third-level wind is 6 meters per second... and so on. There are transitional figures between the winds of all levels, such as 1-2 meters per second for the first-level wind, 2-4 meters per second for the 2-level wind, 4-6 meters per second for the 3-level wind, and so on. Below is a table of wind ratings.
(Meter) 
In order to more accurately measure the size of the wind, people often use a light anemometer in the field to measure the wind. This lightweight anemometer is generally composed of a sensing part and a counter (see the left figure). The induction part is mounted on the cross by three air cups (also four air cups), the air cup can rotate freely on the bearing, and a small frame is used to protect the air cup. The lower part of the middle shaft is connected with the counter, and the wind cup rotates so that the counter also rotates. So the counter is to record the number of rotations of the cup. The counter usually has two or three counts. The large pointer indicates the number of digits and ten digits, and the pointers on the two small numbers indicate the hundreds and single digits, respectively. The lower part of the instrument has a switch (actuating lever) that pushes it up to engage the counter with the sensing part and the counter starts to work. Pulling down the start lever, the counter and the sensing part leave and the counter stops working. When the instrument is placed in a high place and you are inconvenienced by hand, use a small cord to connect the switch. Pull the small rope to open and close during observation. Lightweight anemometers are generally placed in open areas without obstacles, and the body is vertical. Turn off the switch before observing and note the number of pointers. After waiting for a minute or two, turn on the switch and start the stopwatch recording time. At this point, the observer quickly left the anemometer and stood in the downwind direction of the instrument. Nearly 100 seconds after the instrument was started, the observer quickly approached the instrument, turned off the switch for 100 seconds, and noted the second index. The difference between the two readings is calculated. The difference indicates the number of scales the anemometer pointer has taken during the observation time and is recorded in the record table. Dividing this difference by the observation time gives the number of ticks taken by the anemometer per second, taking a decimal. According to the number of ticks per second, the average wind speed (unit: m/s) can be found from the test certificate of the anemometer and a decimal point can be taken.
It is best to observe two consecutive times and take the average value to eliminate the error of the instrument itself and man-made.
Some lightweight wind detectors, in addition to the above-mentioned structural characteristics of the anemometer, are also equipped with a wind vane on the shaft to indicate the direction of the wind, known as wind speed and direction.
Wind level
In the weather forecast released by the meteorological station, we often hear this saying: The wind turns north to south, and winds are 2 to 3. The "level" here is the size of the wind speed.