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Why is the choice of wind speed unit so important? Learn the science and history behind different units!
In meteorology, wind speed is a fundamental atmospheric quantity that reflects the movement of air from areas of high pressure to areas of low pressure. This movement is usually caused by temperature changes. Wind speed is usually measured using an anemometer. Changes in wind speed not only affect weather forecasts, but are also closely related to aviation, maritime operations, construction projects, and even plant growth and metabolic rates.
Wind speed is more than just a number; the science and history behind it shapes how we understand and respond to natural phenomena.
Units of wind speed
Currently, the metre per second (m/s) is the SI unit of speed and is the unit recommended by the World Meteorological Organization for reporting wind speed. Meters per second are widely used in weather forecasts in many countries, especially in Nordic countries. Since 2010, the International Civil Aviation Organization (ICAO) has recommended reporting wind speeds in metres per second when approaching a runway, replacing the previous standard of kilometres per hour (km/h).
Although meter per second is now widely accepted, other units of wind speed have been used throughout history, such as miles per hour (mph), knots (kn), and feet per second (ft/s).
Among them, the Beaufort scale is a traditional wind speed classification method that evaluates the effects of wind based on visual observation in a specific environment. This method is applicable both on land and at sea.
Factors that affect wind speed
Wind speed is affected by many factors that operate at different scales, exerting different forces from the micro to the macro. The main influencing factors include pressure gradients, Rossby waves, jet streams, and local climate conditions. These factors are closely related to each other.
The pressure gradient describes the difference in air pressure between two points in the atmosphere or on the Earth's surface. The greater this difference, the faster the wind flow.
In addition, local weather conditions such as hurricanes, monsoons and cyclones also have a direct impact on wind speed.
Historical wind speed records
So far, the fastest non-tornadic wind speed ever recorded was in Tropical Cyclone Olivia in 1996, when an automatic weather station on Barrow Island, Australia, recorded a wind speed of 113.3 m/s. This data was broken in 2010. Confirmed by the World Meteorological Organization. Tornado-related measurements, on the other hand, are challenging because the strong wind speeds can destroy the measuring equipment.
This data not only shows the powerful forces of nature, but also reflects that the method of measuring wind speed has evolved as technology has improved.
Wind Speed Measurement Tools
Anemometer is one of the common tools for measuring wind speed. There are traditional cup anemometers and ultrasonic anemometers without moving parts on the market. These instruments can operate stably in an environment that does not require daily maintenance and provide accurate measurement results. However, no matter what kind of measuring equipment is used, it requires special design and calibration to ensure that the measured data is reliable.
Wind Speed Considerations in Architecture and Design
Wind speed is a common consideration in structural design, especially in the United States. The design wind speed is often defined as the instantaneous wind speed every 3 seconds, which is the maximum sustained gust with a probability of 1/50 exceeding it each year. . This wind speed definition affects the lateral design of the building.
The understanding and application of wind speed in structural design directly affects the safety of human life and the protection of property.
In Canada, design is usually based on a reference wind pressure, which is based on an average wind speed that has a 1 in 50 probability of being exceeded each year.
ConclusionIn summary, the selection and measurement of wind speed units is not only a scientific issue, but also contains rich historical considerations. As technology advances, our measurement tools and methods are also improving, allowing us to gain a deeper understanding of meteorology. But how do you think future technology will change our understanding and application of wind speed?
