  Global return value estimates of significant wave height and 10-m neutral
wind speed are estimated from very large aggregations of archived ECMWF
ensemble forecasts at +240-h lead time from the period 2003-2012. The upper
percentiles are found to match ENVISAT wind speed better than ERA-Interim
(ERA-I), which tends to be biased low. The return estimates are significantly
higher for both wind speed and wave height in the extratropics and the
subtropics than what is found from ERA-I, but lower than what is reported by
Caires and Sterl (2005) and Vinoth and Young (2011). The highest discrepancies
between ERA-I and ENS240 are found in the hurricane-prone areas, suggesting
that the ensemble comes closer than ERA-I in capturing the intensity of
tropical cyclones. The width of the confidence intervals are typically reduced
by 70% due to the size of the data sets. Finally, non-parametric estimates of
return values were computed from the tail of the distribution. These direct
return estimates compare very well with Generalized Pareto estimates.
