(Joint work with  Andreas Sterl)

The European Centre for Medium-Range Weather Forecasts (ECMWF) has
recently conducted ERA-40, a reanalysis of global atmospheric conditions for the
period from 1957 to 2001. The reanalysis uses ECMWF's Integrated Forecasting
System, a coupled atmosphere-wave model with variational data assimilation. This
is the first reanalysis in which a wave model is coupled with the system used,
and it produced a global wave data set on a 1.5º by 1.5º latitude/longitude
grid. I will present results of extensive validations of the ERA-40 ocean wave
data and show how, using some statistical techniques, the data can be
used reliably to estimate parameters pertaining to both short and long
time scales, such as percentiles and return values. I will additionally show
how climate variability has been influencing ocean waves.