Wind measuring towers (sometimes called meteorological evaluation towers (MET) are used to verify the wind characteristics at a potential site for a wind farm.
Wind Measuring Tower - FAA Guidance for Marking and Identification
On June 24, 2011, the FAA issued their guidance for the marking and identification of METs on a nationwide basis. In summary, the FAA guidance for the marking of METs includes the following points.
- Tower paint stripes of aviation orange and white (top to bottom)
- One high visibility sleeve on each guy wire anchor point plus a second sleeve on the outer guy wire
- Eight spherical marker balls (4 within 15 feet of the top wire connection to the tower, and 4 marker balls at or below the midpoint of the structure on the outer guy wires) and
- All markings should be replaced when faded or otherwise deteriorated.
Why is Marking and Identification Important?
The presence of unmarked METs can be an aviation risk to low-flying aircraft. There are many legal, legitimate users of low-level airspace that are at risk. They include agricultural aerial applicators, med-flight crews and their patients, aerial military operations, aerial fire suppression, livestock roundup, GPS mapping, electrical transmission line construction companies, power line and pipeline patrols, invasive species assessment, wildlife monitoring, general aviation, and more.
FAA Advisory Circular - Obstruction Marking and Lighting
See Chapter 3 paragraph 30-34 for details on Painting and Spherical marking balls for wind measuring towers
Nebraska Department of Aeronautics
List of all registered MET towers in Nebraska
Nebraska Aviation Trades Association
Sprayer pilots are one of many users of low level air space. Proper marking of MET towers will protect pilots.
Wind measuring towers are typically just shorter than 200 feet tall. Above which a light would be required. Painted stripes and high visibility balls make the tower stand out and easier to see for low flying pilots.