Study of extreme wind conditions in the Aegean Sea. The effect on maritime accidents.

Postgraduate Thesis uoadl:2686429 724 Read counter

Κατεύθυνση Στρατηγικές Διαχείρισης Καταστροφών και Κρίσεων
Library of the School of Science
Deposit date:
Sartzetakis Eftychios
Supervisors info:
Δρ. Παναγιώτης Νάστος, Καθηγητής τμήματος Γεωλογίας και Γεωπεριβάλλοντος, ΕΚΠΑ
Original Title:
Μελέτη των ακραίων ανεμολογικών συνθηκών στο Αιγαίο Πέλαγος. Η επίδραση στα ναυτικά ατυχήματα.
Translated title:
Study of extreme wind conditions in the Aegean Sea. The effect on maritime accidents.
Wind is one of the most important natural phenomena on the planet as it consists a major feature of the atmosphere, that influences the earth's ecosystem. From the early ages, man took advantage of the wind's qualities on his road to development. But at the same time, wind constitutes a potential threat for humanity, as a causal factor of natural and technological disasters, especially in its strong and extreme forms. Nowadays, especially under the emerging climate change, extreme wind and extreme weather events in general, constitute an essential domain of disaster risk reduction studies.
The wind regime of the Aegean sea indicates a great departure from the general pattern of the observed winds in the wider Mediterranean sea region, with northern winds in all seasons, although sporadic southern winds occur during the winter. Winter can be described as the most "windy" season of the year but yet during summer, there is also an intense wind regime, due to the emergence of the "Etesians", one of the most stable wind systems on a global scale. Based on the analysis of the provided data by the National Meteorological Service, strong winds in the Aegean sea indicate an annual presence of 20%. The island complex of Cyclades has the strongest wind conditions in relation to the other groups of the Aegean islands, while the highest prevalence rates of strong winds are observed in the meteorological stations of Karpathos and Naxos. The study of extreme winds in the Aegean sea resulted correspondent return periods with attributed values ranging between 60 and 100 knots, depending on the stations and the return times of the calculations.
At the same time, the Aegean Sea is an international seaway used by the global passenger and commercial marine fleet. In the time period between the years 2003 and 2015, 516 marine casualties of different types and extent of consequences were recorded in the Aegean sea. The frequency of the accidents indicated upward trends over the summer period, probably as a result of the more dense maritime traffic, while 40% of the total number of accidents occurred in Cyclades. Although weather conditions are not officially recorded as a main cause of marine casualties in the Aegean, a particular increase of their occurrence frequency was observed, in relation to the wind intensity. This statistical observation can be interpreted with the aid of the accident evolution models, such as the one of J. Reason, where strong winds can act as a multilevel causal factor of marine accidents. Through the analysis of the relative data, it was estimated that during the transition from light to moderate wind conditions, the probability of a naval accident occurrence in the Aegean sea is increased by four times and during the transition from light to strong winds by seven times.
Main subject category:
Aegean Sea, extreme wind, return period, maritime accident, risk
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