Hindcast data

Hindcast data are generated by running numerical models for waves and wind based on input from meteorological observations. One of the goals with hindcast data is to produce reliable extreme value statistics taking long term trends in the environment into account. It is often considered more robust than extrapolation of direct measurements of waves and wind.

Hindcast data are usually represented as long time series with duration of 50 years or more, and 3 hours sampling interval. Moreover, this is the input to other representations, such as scatter diagrams and long-term statistical distributions.

Note that hindcast data usually describes wind and waves, but not current. If current needs to be included in the analysis, some assumption has to be made about how current is related to waves and wind. It has been assumed in some projects that the current propagation direction is rotated 15 degrees relative to wind due to the Coriolis effect. The surface current velocity may be assumed proportional with the wind velocity. See [dnvrpc205]

where \(V_c^{wind}\) is the wind-driven surface current, \(k\) =0.015-0.03 and \(V_w\) is the 1 hour wind velocity at 10 m height above the sea surface. Other components of the total current (tidal currents, longshore currents, circulation currents, …​) may be assumed as a constant contribution, such that