Remote measurements of the spatial mean ocean wind speeds were obtained using Doppler spectra resolved to 0.08 Hz from high-resolution HF skywave-radar backscatter measurements of the ocean surface. A standard deviation of 2.4 m/s resulted from the correlation of observed winds over the ocean and the broadening of the Doppler spectra in the vicinity of the higher first-order Bragg line. This broadening, for Doppler spectra unperturbed by the ionospheric propagation, is proportional to the increase in power caused by higher order hydrodynamic and electromagnetic effects in the vicinity of the Bragg line and inversely proportional to the square root of the radio frequency. A lower bound on the measure of wind speed was established at 5 m/s by the low resolution spectral processing and low second-order power. An upper limit is suggested by the steep slope in the region of the sea backscatter spectrum outside the square root of two times the first-order Bragg line Doppler.
[1]
W. Pierson,et al.
A proposed spectral form for fully developed wind seas based on the similarity theory of S
,
1964
.
[2]
J. M. Headrick,et al.
Tests of remote skywave measurement of ocean surface conditions
,
1974
.
[3]
Robert H. Stewart,et al.
Radio measurements of oceanic winds at long ranges: An evaluation
,
1975
.
[4]
J. Maresca,et al.
High-resolution mapping of oceanic wind fields with skywave radar
,
1977
.
[5]
J. Barnum.
Skywave polarization rotation in swept‐frequency sea backscatter
,
1973
.
[6]
J. M. Headrick,et al.
Sea backscatter at HF: Interpretation and utilization of the echo
,
1974
.