Sutron Corporation Satlink Operations & Maintenance Manual, Rev 8.04.2 11/3/2016 pg. 84
Mean Magnitude Unit – This is the vector average of the wind speed using unit
vectors. The mean magnitude unit of 5mph at 0 for 1 hour and 100mph at 90
for 1 hour is 0.707. This is found by adding the two vectors, finding the
magnitude of the resultant vector, and dividing by the number of vectors in the
average (two, in this case). Since the mean magnitude unit is an average of unit
vectors, it will always be between 0 and 1.
Mean Magnitude Wind – This is the vector average of the wind speed which
takes direction into account. Here, the average of 10mph at 0 for 1 hour and
20mph at 90 for 1 hour is 11.2 mph.
Mean Direction Unit – This is the wind direction (in degrees) not weighted for
wind speed. Here, the average of 10mph at 0 with 20mph at 90 is 45. This is
the value you’d get with a simple average of the direction if no 0-360 crossover
occurred.
Mean Direction Wind – This is the wind direction (in degrees) weighted for wind
speed. Here, the average of 10mph at 0 with 20 mph at 90 is 63.4.
Resultant angle =
= 45
MnDirUnit = 45
Vector sum =
MnMagWind =
Vector sum =
MnMagUnit =
Resultant angle =
= 63.4
MnDirWind = 63.4
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