How is wind measured? And how can wind measurement possibly help predict the weather?
Find out how wind is measured using tools like anemometers and wind vanes. These tools let you appreciate the importance of calculating wind direction and speed.
Can We Measure the Wind?
Yes, we can measure the wind using two specific parameters: its speed and direction.
Knowing how these 2 wind measurements interact is essential for predicting the weather and preparing for upcoming extreme conditions.
Wind speed explains how fast the air is moving, while wind direction describes which way the wind is going. These variables let you know the surface waters’ mixing, evaporation rate, and seiche and storm development.
The measurement unit of wind speed is “miles per hour,” while the unit of measurement for wind direction is in degrees.
It should also describe the direction in which the wind originates. For example, we can say “180 degrees due south.”
How to Measure Wind Speed
The UK and the US measure wind speed using miles per hour. In other countries, they use kilometers per hour.
Knots are another unit of measurement for aeronautical and maritime use. One knot equals a nautical mile per hour, which is 1.852 kilometers per hour.
Fast and strong winds are called a gust. The wind gust refers to the highest wind speed within ten minutes. Only use the term gust if the recorded wind speed is a minimum of 10 knots of wind speed.
Another term to remember is peak wind. Peak winds are the highest record of gusts since the previous observation. Meteorologists often observe once an hour.
The National Weather Station
It provides several alerts for more powerful and faster winds. They include Wind Advisory, High Wind Watch, High Wind Warning, and Extreme Wind Warning.
A Wind Advisory is NWS alert that is least likely to cause severe weather. It warns people about the sustained winds of 31 to 39 mph or 46 to 57 mph wind gusts. The Extreme Wind Warning alerts residents about possible adverse weather conditions due to 115mph of wind.
Before learning how to measure wind speed, it’s essential to know that wind speeds on your nightly weather report are not the actual wind speed values. These numbers are the average wind speed. The forecast of sustained wind speeds in hurricanes is also averaged.
There are many tools you may use to obtain wind speed information. Take a look at these reliable objects.
Cup Anemometer
The cup anemometer is a popular weather instrument for gathering accurate wind speed information. The three or four items spin as the wind moves.
The number of revolutions per minute determines the intensity of the wind.
Meteorologists had to manually count the spins in a single minute in earlier times. It’s a good thing computers now exist to measure the lapses in a minute frequency.
These cups for wind speed are traditional instruments that are hemispherical or conical. Some of them come with a wind vane to create traditional cup-and-vane anemometers.
Sonic Anemometer
A sonic anemometer is a contemporary tool for measuring wind speed. You’ll often find them in a professional or personal weather station.
Unlike the anemometer cups, sonic anemometers do not move. Instead, they measure the exact wind speed through acoustic signals. Two transducers at the end of the arms are responsible for mediating these signals.
The sonic anemometer can also obtain an estimate of wind speed and direction. It senses whether there is a northerly wind, westerly wind, and so on.
One problem with sonic anemometers is the airflow distortion due to their structure. You can fix this by modifying the wind tunnel calibrations.
Propeller Anemometers
The propeller anemometer is a less common propeller with three or four blades. The blade anemometer uses flat objects or planes that rotate in the wind’s direction, unlike the cup anemometer.
The rotation speed is also directly proportional to the wind speed. Make sure to align the blade with the wind direction so that its sensor reaches the required parts.
This anemometer type is easy to use. However, it’s prone to freezing which might cause malfunctioning.
How to Measure Wind Direction
For some reason, we often overlook the direction of the wind because we worry more about the speed. But the wind direction is also a vital parameter that provides information on the future weather.
When measuring the direction of the wind, the focus is where the wind comes from. It’s not about where it’s heading toward. So, a southerly wind is a wind that blows from south to north. And an easterly wind comes from the east to west.
There are fewer tools to measure this variable. Check out the standard instrument to use when calculating the wind direction.
Wind Vane
The typical wind vane or weather vane lets you know where the wind goes using its fin and pointer. It’s the weather tool with the most straightforward design because it only rests on a spindle. The wind vane works on a spinning mechanism that depends on the direction.
To know where the wind is going, look at the direction the pointer lands. The wind pushes the large fan so that a southerly wind may send a pointer toward the “S.”
Decorative wind vanes feature a steady base with the same north, west, east, and south labels.
Some consider the wind vane unnecessary because it’s not always accurate. The anemometer can already give you data on wind direction alongside wind speed.
Other Instruments for Wind Measurement
The best measurement for wind intensity considers both speed and direction. The correct term for this is wind velocity. Here are other instruments to check the wind velocity aside from the anemometer and vane.
Windsock
The windsock is another device that calculates the wind direction. It uses a massive cloth in the form of a tube, which extends as the wind blows. Its ability to stretch depends on the wind speed too.
Like the wind vane, if the tip of the windsock is pointing west, it means you are experiencing west winds. To estimate the wind speed, check the angle of the windsock.
Each stripe is equivalent to 3 knots. The wind speed is around 15 knots or higher when it’s fully stretching.
Windsocks are more common in airports and airfields. The size must be big enough to stay visible to pilots.
You can also find these instruments on roads where there is a risk in terms of wind. They include a floodlight so that people will see them in the dark.
Laser Interferometer Anemometer
This anemometer is a laser wind sensor that gives more precise values of the wind intensity. It yields wind speed measurement through beams of light rather than ultrasound.
The laser beam splits into two through the principle of interferometry. An expert keeps the first half intact and then lets the other one be in contact with what you want to measure. Then, they calculate the fringe spacing on the light pattern.
When assessing the airspeed, let the beam pass through any chamber with wind, such as a wind tunnel. Meteorologists also use a pipe or tube.
How to Measure Wind for Wind Turbines
Wind turbines are enormous structures in wind farms that transform wind energy into electricity. They do this through the rotor blades’ aerodynamic force, operating like airplane wings or helicopter blades.
Communities use wind turbines for offshore wind projects, land-based wind, and distributed wind. Land-based wind turbines, for example, vary from 100 kilowatts to plenty of megawatts.
Measuring the wind speed for wind turbines is crucial because their performance depends on this weather parameter. It’s also another reason why the location of the turbine matters.
Cup and ultrasonic anemometers are too small to mount on the nacelle or the part of the turbine that changes the kinetic energy to mechanical energy.
What They Need
Wind turbines need larger, ground-mounted sonic instruments to measure the wind speed and direction. They can also use a sonic wind profiler or solar unit to observe the wind directions and speed.
These devices can obtain accurate wind information at the turbine heights regardless of the location and weather. Using a truck, they can operate through solar power and move from one place to another.
One benefit of the solar is that it provides the same information as the basic anemometer. There is no need for professional analysis because the user can read the data through a satellite wind data service.
Bottom Line
Learning how winds are measured will give you several clues about the incoming weather. The wind speed describes how fast the wind is over a given period of time. Meanwhile, wind direction shows the direction from which the wind stems from.
What instruments do you use for measuring wind? I want to know your thoughts and questions in the comments below.
Use a wind vane and anemometer to measure these wind parameters. Windsocks are also acceptable tools, although they don’t give exact numbers for the wind speed. Are you looking for more info like this? Check out our guide on how to go green at home.
