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Wind measurement error sources
#1
Hello,

last monday as some of you might know we had stormy weather here.
The wind was (at least compared to what is normal here) quiet strong and I measured one single gust of about 160km/h.
See graph attached (note the units on the Y-Axis are wrong - it should be km/h).

From all I know it was a very strong gust and also some station here measured values in this range.

I'm using a FO anemometer mounted about 2.5m over the ground.

Config is like this:
Code:
// --------------------------------------------------------------------------------------
// Define Wind Speed and Wind Gust resolution - Read carefully
// --------------------------------------------------------------------------------------
#define VP2_WIND_RESOLUTION 2 // If set to 2, set Cumulus Wind Speed and Wind Gust multipliers to 0.448. Wind Resolution 0.72 Km/h
// If set to 1, set Cumulus Wind Speed and Wind Gust multipliers to 0.224. Wind Resolution 0.36 Km/h
// WARNING !!!
// Setting this variable to 2 or 1 allows a better wind speed and gust resolution,
// but also limits the maximum readings to 183.6 Km/h and 91.8 Km/h, respectively.
// If set to 0, system uses Standard Davis wind resolution (1 mph or 0.1mph with LOOP2).
// Weather Display users should set this option to 0 - Standard Davis wind resolution
// --------------------------------------------------------------------------------------
// Define use of Wind Gust Spike prevention routines (mostly for FO anemometers)
// --------------------------------------------------------------------------------------
#define WIND_SPIKECONTROL 1 // 0= Disable, 1= Enable

Multipiliers in WeeWx are also correct.


Can you imagine any other sources influencing the reading besides of the FO Anemometer.

I can not say the measurement is wrong but I think the reading is too much. 130km/h or around that would seem more realistic.

Regards,
engolling


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