Return periods of Medicanes: a wind-wave approach combining numerical weather prediction models and stochastic processes

Within an environment characterized by continuous changes, the study and analysis of extreme weather events affecting human is of great importance. In this context, cyclones with tropical characteristics are also evident in Mediterranean Sea. Regardless their rare occurrence, their extremity and presence in dense populated areas may lead to severe social and financial implications. The interest for the study of such events has been increased lately, however their return periods are not yet thorough examined.

The scope of this work lies in the study of the recurrence interval and the intensity of Mediterranean tropical-like cyclones (Medicanes). An online coupled atmospheric and wave modeling system is employed for the high resolution simulation of the documented Medicanes during the last decades. Wind speed, wind gust, significant wave height and maximum wave height are the parameters analyzed, employing the principles of Extreme Value Theory. Different methodologies are followed and tests are carried out for the system optimization and the quantification of the associated uncertainties.

The results regarding the frequency of occurrence of Medicanes and the comparison between the different approaches not only present scientific interest, but also can be used in early warning systems and reinsurance.