Weather station reports. True or magnetic
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Wind direction is defined as the direction from which the wind blows, and is measured clockwise from geographical north, namely, true north (based on the World Geodetic System 1984 (WGS-84) and its Earth Geodetic Model 1996 (EGM96)). - source: WMO
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Even in METARs? I guess METARs use magnetic.
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@ivo
I copy from https://www.faa.gov/air_traffic/publications/media/aim.pdf
Chapter 7, section 1
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I am not familiar with weather reports in the flight sector but according to German weather service (DWD) it is reported in true north(German source: DWD).
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@ivo
Maybe you refer to:
If you read it (METAR), it's true. If you hear it (ATIS), it's magnetic.All charts and textual sources (METAR, TAF, winds aloft, surface analysis charts, etc) use true north as the reference.
ATIS/AWOS/ASOS broadcasts, or any information a controller gives you over the radio, is magnetic.
See:International Airport Example 1,
here https://en.wikipedia.org/wiki/Automatic_terminal_information_service -
@ivo
As the magnetic declination in Czech Rep. is 3~5 degrees and wind direction is given in tens of degrees, you have no problem!
But if you fly to Greenland ....
https://screenshots.firefox.com/kCNSJ4D19uIqOUNs/upload.wikimedia.org
the ATC will give you wind dir. (for landing) in magnetic
(also runways names (01 up to 36), refer to magnetic azimuth in tens of degrees). -
No problem
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@ivo
I totally agree with @Gkikas-LGPZ .
The best mnemonic for it is: WRITTEN --> TRUE; SPOKEN --> MAGNETIC. -
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True north is a fixed reference point based on the Earth's geographic poles. This consistency is crucial for aviation and maritime navigation, where precise wind direction information is essential for safe travel.
Magnetic north, influenced by the Earth's magnetic field, varies depending on location. Reporting in true north eliminates the need for constant adjustments based on location. -
Apologies for the brevity! The term "True" in this context typically refers to the type of north indicated by a compass or navigation system that aligns with the Earth's geographic north pole. It contrasts with "magnetic north," which is the direction a compass needle points due to the Earth's magnetic field.
