National Oceanic and
Atmospheric Administration
United States Department of Commerce


FY 1989

Comparison of equatorial winds as measured by cup and propeller anemometers

Freitag, H.P., M.J. McPhaden, and A.J. Shepherd

J. Atmos. Ocean. Technol., 6(2), 327–332, doi: 10.1175/1520-0426(1989)006<0327:COEWAM>2 (1989)

This study compares the performance of cup vs. propeller anemometers from surface-following taut-line moorings in the equatorial Pacific. Vector wind components at 4 m above the sea surface were measured from a mooring instrumented with a cup anemometer and concurrently from a nearby mooring instrumented with a propeller anemometer. Mean wind conditions over the 115-day comparison period were typical of the southeast trade winds with a mean speed of 6.7 m −1 and a steadiness factor of 0.96. Differences between the time series measured by the two wind sensors were small. Mean speed differed by 0.02 m s−1 and mean direction by 1.4°. Correlation coefficients for 2-hour vector-averaged zonal component, meridional component, speed and direction were 0.97 or above. The small differences in measurements imply that the two systems are equally suited for near-surface wind observations under typical tradewind conditions.

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