10 metre wind speed, 2-D wave spectra, coefficient of drag with waves, mean direction of total swell, mean direction of wind waves, mean period of total swell, mean period of wind waves, mean square slope of waves, mean wave direction, mean wave period, mean wave period based on first moment, mean wave period based on first moment for swell, mean wave period based on first moment for wind waves, mean wave period based on second moment, mean wave period based on second moment for swell, mean wave period based on second moment for wind waves, peak period of 1D spectra, significant height of total swell, significant height of wind waves, significant wave height, wave spectral directional width, wave spectral directional width for swell, wave spectral directional width for wind waves.

2-D wave spectra are available for 12 directions and 25 frequencies.

There has been a problem with the wave analysis since the introduction of ERS data at the start of 1991. The size of waves of low magnitude (less than 1 metre) may be too high and the corresponding mean periods too high.

The problem is largely confined to enclosed or semi-enclosed seas such as the Mediterranean Sea, Black Sea, Baltic Sea, the Gulf of Mexico and the East China Sea.

There is a problem with the ERA-40 archives in that wind and waves are underestimated for medium to large values, especially in enclosed areas such as the Mediterranean Sea. This has been reported by Caires and Sterl during their validation exercise as reported in their paper:

Caires, S. and A. Sterl, 2005a: A new non-parametric method to correct model data: Application to significant wave height from the ERA-40 reanalysis. J. Atmospheric and Oceanic Tech., 22(4(), 443-459.

Their work and ways to overcome some of the problems are presented in the online wave atlas at:

http://www.knmi.nl/waveatlas