According to the influence of wind on ground objects or oceans, it is preliminarily divided into three levels. From 1946, the wind power level was expanded to 18 (0- 17). PUFOF of style sheets can only be used in the sea, and can be used after land improvement. 1947 12 international meteorology was temporarily officially recognized by him.
introduce
Beaufort Scale is a wind scale, which depends on the influence of wind, dust, land objects, fishing boats and fishing grounds. It is usually used to estimate wind speed. According to the intensity, the wind power varies from 0 to 12 and *** 13, and the current level is recommended by the World Meteorological Organization. Later, until the 1950s, the progress of human paddling instruments made the wind force in nature can actually be greatly exceeded, and the wind force level was expanded to 17, that is, * * * * 18. However, the classification rate of WMO Marine Meteorological Service Manual is only 0 to 12, and it is not recommended to extend it from 13 to 17.
Measuring tool
Light anemometer, usually used to measure the magnetic field of wind power, generally consists of a sensing part and a counter.) The sensing part is installed on the cross, and there are three air cups (there are also four air cups). The air cups can rotate freely on bearings, and the external small frame protects the air cups. The lower part of the central shaft contacts the counter and rotates the air cup, and the counter rotates. Therefore, the counter is the number of revolutions of the air cup. A counter usually has two or three records, a big pointer indicates a point and ten numbers, and two small counters indicate hundreds of sums and numbers.
There is a switch (starting lever) at the lower part of the instrument, which is pushed upward to make the counter engage with the sensing part, and the counter starts to work. Lower the starting lever to the counter and leave the sensing part, and the counter stops working. The height of the light wind speed together, when the hand is not open, the switch can be connected with the small rope. Pull a small rope while observing.
Light pulses are generally placed around, without high obstacles, and their shapes are vertical. Turn off the switch before observation and write down the number of hands. After waiting for a minute or two, start and stop recording time and turn on the switch. At this point, the observer quickly left the anemometer and stood at the bottom together.
When the instrument starts nearly 100 second, the observer quickly approaches the instrument, turns off the switch within 100 second and writes down the number of seconds. According to the two readings before and after, the difference indicates the number of marks on the anemometer pointer record table taken during the observation time. In addition to the observation time, find the difference, find the number of marks per second, and take a decimal. According to the number of tumors per second, find the average wind speed (unit: m/s), and take one minute. It is best to observe it twice, the cost is average, and the equipment itself and human error are reduced.
describe
When creating Beaufort style, it is a scoring method by observing phenomena. There is no fixed wind speed according to the state of the ocean or waves.
1830 The Royal Navy is a Punubu-style record standard. From 1850 s, the general floating wind level is also used for general navigation, and then the wind speed is measured by the wind cup anemometer. The wind speed is standardized at 1923, and the Beaufort wind power level is slightly modified, which is popularized for meteorological use. [4] However, the classification rate of WMO Marine Meteorological Service Manual is only 0 to 12, so it is not recommended to extend it from 13 to 17.
Up to now, there are still different wind speeds of 0 ~ 12, and the Beaufort scale is adopted. However, because the wind speed can be more accurate, many western countries have abandoned the wind level in ocean forecasting and changed it to every 5(kt) (with a few exceptions in English).