Reconstructing 50 years (1975-2024) of wave climate over the Mediterranean sea using a high-resolution hindcast

This study presents the results of a long-term wave hindcast covering the period 1975–2024 over

the Mediterranean Sea. The hindcast was produced through a dynamical downscaling approach,

based on a chain of numerical models. ERA5 global reanalysis data were downscaled using the

BOLAM and MOLOCH atmospheric models, providing the wind forcing for the WW3 wave model,

which simulated the sea state. WW3 adopts an unstructured computational grid with variable

resolution, reaching up to 500 meters along the Ligurian and Tyrrhenian coasts (Italy), allowing for

a detailed representation of the coastal wave climate.

Although hindcasts do not assimilate observational data, validation against in-situ observations

shows that the generated wind and wave fields are robust and reliable, providing added value

compared to global reanalyses. The resulting dataset represents a valuable resource for wave

climate studies, coastal risk assessment, and the analysis of long-term variability in the

Mediterranean region.

The availability of such a long-term, high-resolution hindcast enables several potential

applications. It provides a solid baseline for trend analysis and climate variability studies and can

support the identification of suitable areas for offshore renewable energy development. We

present user cases in which the dataset was used to assess both atmospheric and marine

conditions over sea areas involved in particularly sensitive operations, where atmospheric

dynamics play a critical role. We show statistical analyses performed to produce monthly waiting

time tables (expressed in hours), estimating how long it typically takes for sea state conditions to

fall within the operational thresholds required to safely carry out planned maritime activities.

Finally, we conclude with some considerations on the computational efficiency of the modelling

framework adopted, which makes the dataset particularly suitable for operational updates and

facilitates its regular extension to future years.