C. Rufenach, A NEW RELATIONSHIP BETWEEN RADAR CROSS-SECTION AND OCEAN SURFACE WIND-SPEED USING ERS-1 SCATTEROMETER AND BUOY MEASUREMENTS, International journal of remote sensing, 16(18), 1995, pp. 3629-3647
The ERS-1 spacecraft scatterometer, C-band VV polarization, acquired r
adar cross-section measurements over the global oceans during 1992 and
1993. We investigate the cross-section dependence on mean wind speed
U using collocated buoys within +/-25 km of the scatterometer cells. T
hese collocated measurements result in over 75000 matches in two diffe
rent oceanic regions. The buoys measure hourly mean wind speeds from 0
.2-10 m s(-1) and 0.2-18 m s(-1) in the equatorial Pacific Ocean and a
t mid-latitudes off the North American coasts, respectively. We presen
t experimental evidence for a new and compact exponential model depend
ence on wind speed. The previously used power-law form inadequately ch
aracterizes the cross-section measurements based on a single index ove
r a large wind speed range. The cross-sectional slope varies from abou
t zero dB/m s(-1) at high wind speeds U = 18 m s(-1) and small inciden
ce angles theta = 20 degrees to about 1.3 dB/m s(-1) at low wind speed
s U = 3 m s(-1) and large incidence angles, theta = 55 degrees. The CM
OD4 model significantly underestimates the radar cross section measure
ments for U less than or similar to 3 m s(-1) whereas the exponential
model exhibits less bias.