On the use of drift ice thickness statistics from a Copernicus reanalysis product for fatigue damage calculation

In bodies of water where ice is not an annual occurrence, such as in the Southern Baltic Sea, the design of offshore wind turbines is complicated by the difficulty involved in estimating the relevant ice parameters (thickness, velocity, and strength) and their corresponding probabilities of occurrence (return periods). In this paper, the use of a Copernicus reanalysis product is evaluated for its applicability in preparing drift ice thickness distributions in the design phase of offshore wind turbines. An area surrounding the Kriegers Flak wind farm site in the Southern Baltic Sea is used as a case study. The drift ice thickness statistics of ice within the region which could potentially drift into the site were weighted according to drift directions, based on the wind direction frequency in the area. We found that between 1993-2017, drift ice at Kriegers Flak mainly occurred in 1996 with 0.1 m maximum ice thickness, in good agreement with estimations reported in the literature. Ice thickness probabilities have been created from the 1996 winter data and used as input for a fatigue damage analysis of an offshore wind turbine. The additional steps required to improve the suitability of Copernicus reanalysis data for use as input into design calculations are discussed.