Design changes needed for extreme storm predictions?

2009-06-09

Oslo: DNV is coordinating the EU project ‘Extreme Seas’ as scientific research into climate change indicates that storms will get more severe and extreme waves could increase in height. A review of meteorological and oceanographical data used in load and fatigue calculations is necessary and classification society rules for ships and offshore structures may require amendment.

While specific changes in sea conditions will vary geographically, it appears that storm tracks have already moved closer to the poles in both hemispheres and it is predicted that storms and cyclones will become less frequent but more intense indicating that extreme wave heights may increase.

These are some of the findings reported in a white paper developed by DNV this spring. DNV has evaluated the latest research globally and is preparing for climate changes that might affect design calculations and the rules needed for the classification of ships and offshore structures.

“Any revision of design procedures that accounts for climate change needs to be well founded on good scientific and technological findings,” said Dr Øyvind Endresen, programme director DNV Research & Innovation. “Today we use historical MetOcean data for predicting the maximum environmental loads experienced at sea and the possible failure of ships and structures due to fatigue. A consistent approach to handling changing trends in this data needs to be developed now so that we continue to make risk assessments based on the latest, most accurate data available.”

Much of the climate change research undertaken so far has focused on average increases in temperature and sea level, and ice melting but it is extreme wind and wave conditions that pose the greatest structural risk to ships. The aim of the four million Euro Extreme Seas project is to bring wave modelling, ship dynamics and design specialists together to develop the tools required to take shipping safely through future meteorological and oceanographical changes. Advanced physical, mathematical and statistical models will be developed and tested for passenger, container and tanker ships.

“Climate change research must be followed closely. A new methodology for incorporating time-dependent statistics in design procedures could be implemented within the next few years. DNV continues to collaborate with universities and research organisations to maintain leadership on behalf of the shipping community,” said Dr Elzbieta Bitner-Gregersen, Extreme Seas project coordinator at DNV.

The actual Extreme Seas project is planned to start 1st September 2009 and includes eleven partners.

DNV