A comparison of ship- and scatterometer-derived wind speed data in open ocean and coastal areas

Quality controlled wind speed observations from merchant ships have been co mpared with ERS-1 scatterometer data. The ship and satellite wind speed pai rs were well correlated at 120km separation in the open ocean, reducing to 40km in the North Sea. The maximum allowed separation of ship and scatterom eter wind speed pairs had to be further reduced to 20km in the North Sea to avoid matching of coastal ship wind speed data with scatterometer data fro m more exposed regions. Spurious biases in the comparisons were caused by t he error variability of the scatterometer data (0.5 m s(-1)) being signific antly less than that for the ships (2.0 m s(-1)). The unbiased regression w as: U-10n(ship)= 1.025 x U-10n(satellite)+ 0.255 No significant enhancement of the scatterometer wind speeds occurred in the coastal region.