Assessment of Global Wave Datasets for Long Term Response of Ships

Abstract

Ship structure design process begins with the evaluation of environmental conditions a ship is expected to withstand. This paper deals with wave data, and more specifically with global wave dataset that can be used to evaluate waves encountered by a ship along its lifetime track. Benchmark of existing global hindcast datasets is performed, having in mind its use to assess extreme ship response. The presented comparison is thus not limited to the mean and standard deviation but includes also extreme significant wave height. Wave period that can significantly modify ship behaviour is also investigated. Five different hindcast datasets are selected for the present analysis and compared with buoy and altimeter data. Area of interest is region far from the coast, and more specifically the North-Atlantic, which is currently considered the most severe for sailing ships. In such area, the global wave models are expected to provide decent results (as opposed to near shore area where a local mesh would be required). Two datasets are provided by ECMWF (ERA5 and ERA-Interim) that uses WAM model, two others are from NOaAA/NCEP and Ifremer and use WaveWatchIII, finally WAV-ERYS dataset is provided by the Copernicus program, and uses MFWAM. Some differences are observed in the wave parameters projected by different models, especially on extremes. Reasons for this scatter are briefly discussed, but more emphasis is put on the consequence for ship response. This work has been performed within IACS (International Association of Classification Societies) framework.

Ocean waves in the southwestern Atlantic Ocean: An evaluation of global wave models

“…Crespo et al (2022) found that WAVERYS is the dataset that more realistically represented the wave heights observed by buoys and platforms over the southeastern Brazilian basins. On the other hand, wave parameters produced given by ERA5, NOAA, IOWAGA and WAVERYS were compared with buoy and altimeter data in the North Atlantic and Pacific Oceans (de Hauteclocque et al, 2020). It was pointed out that ERA5 and WAVERYS have a better performance due to the satellite data assimilation.…”

“…Global wave models have improved their performance by providing reliable wave parameters with high resolution and coverage even at near‐shore areas, quite close to the coast (Ahn, 2021; Crespo et al, 2022; de Hauteclocque et al, 2020). Therefore, they are useful for describing the wave climate in regional and coastal projects.…”

Comparative analysis of the long-term extreme VWBM calculated according to IACS Rec. No 34 rev 1 and rev 2

“…34 rev 2 (2022). Thus, GWS is revised in [14] and [15], wave parametrization in [16], while the consequence assessment, indicating that the extreme wave loads are reduced from 10% to 30%, is described in [13].…”