Operator`s manual

56
Installation, Operation and Maintainance of Buoy Operated Automatic Meteorological Stations
Annex 7: Wind Vector
Wind speed and direction are measured with a polar sensor (R. M. YOUNG 05103). The raw data are processed to
a wind vector, which includes:
a. Mean horizontal wind speed, S [m/s]
b. Unit vector wind direction, 1 [degrees]
c. Standard deviation of wind direction, (1) [degrees]
Mean horizontal wind speed is calculated using:
S = (S
i
)/N
In which the indices i denotes each individual sample.
Unit vector wind direction is calculated using:
1 = Arctan (Ux/Uy)
where:
Ux = (sin
i
)/N
Uy = (cos
i
)/N
Standard deviation of wind direction is calculated using (Yamartino algorithm):
(1) = arc sin()[1 + 0.1547 
3
]
where:
 = [1-((Ux)
2
+ (Uy)
2
)]
Ux and Uy are calculated as above.
Reference: Campbell Scientific CR10X Operator’s Manual
Annexes