Vaisala WS425 - Manual (Page 18)

USER'S GUIDE____________________________________________________________________
18 __________________________________________________________________ M210361EN-E
Polar Wind Speed and Direction
The wind speed (WS) is represented as a scalar speed in selected units
(m/s, kt, mph, km/h). The wind direction (WD) is expressed in degrees
(
°).
0212-044
Figure 1 Different Wind Speed and Direction Presentations
Wind Speed X and Y Components
The wind speed (x, y) is represented as two scalar speeds, one parallel to
the N-S direction (x) and the other (y) parallel to the W-E direction The
speed unit may be m/s, kt, mph, or km/h.
x = WS
× cos (WD)
y = WS
× sin (WD)
Scalar Averaging of Wind Speed and
Direction
The scalar average of wind speed and wind direction is available in both
SDI-12 submode B and serial modes. The time between each consecutive
wind speed and wind direction measurement is one second. Each wind