Surface wind is primarily measured using specialized instruments, though estimation methods exist when instruments are not available.
Primary Measurement Methods
The most common and accurate way to measure surface wind involves using specific instruments designed to detect wind direction and speed.
Using Instruments
As referenced, surface wind is usually measured using a wind vane and a cup or propeller anemometer. These instruments are typically installed at weather stations or observation points to provide continuous data.
- Wind Vane: This instrument is used to determine the direction from which the wind is blowing. It typically has a fin or tail that catches the wind, causing it to rotate on a vertical axis until it points into the wind.
- Anemometer: This instrument is used to measure wind speed. There are different types, commonly the cup anemometer (spinning cups that rotate faster with increasing wind speed) or the propeller anemometer (a propeller-like rotor that spins with the wind).
Alternative Method
When instruments are not available or are malfunctioning, meteorologists or observers may resort to an alternative method.
Subjective Estimation
When a measuring instrument malfunctions, or when no such instrument is available, the wind direction and speed may be estimated subjectively. This involves observing the effects of the wind on the environment, such as the movement of trees, flags, smoke, or waves on water, and comparing these observations to a standard scale like the Beaufort Wind Scale. While not as precise as instrument-based measurement, subjective estimation provides valuable information in the absence of technical data.
