AIR Releases New NWP-based European Extratropical Cyclone Model

May 16, 2006

AIR Worldwide Corporation announced the release of its third generation numerical weather prediction-based (NWP) European Extratropical Cyclone Model. “The update further advances AIR’s industry-leading application of NWP technology to enable insurers to better estimate potential losses from extreme windstorms in Europe through a new approach based on the principle of Available Potential Energy,” said the bulletin.

“AIR’s European Extratropical Cyclone Model is highly regarded within the European insurance community for its innovative use of numerical weather prediction technology,” stated Erik Ruttener, Head of Global Natural Hazards at Swiss-based reinsurer Converium. “AIR’s enhancements will enable Converium to further deepen the understanding of our extratropical cyclone risk in Europe.”

“AIR has invested more than ten years of research and development integrating NWP technology into its catastrophe models,” noted Yoern Tatge, managing director of AIR Worldwide GmbH. “The latest model release leverages advancements by AIR meteorologists in the application of NWP technology to windstorm models. The new techniques have been peer-reviewed by Dr. Robert Fovell of UCLA, a pre-eminent atmospheric scientist and a recognized expert in NWP technology.”

Describing the model, AIR said that its “meteorologists developed an original application of Available Potential Energy (APE), a well-known meteorological principle, depicting the build-up of mid-latitude energy. The relationship between APE and storm intensity was used to refine the distribution of winds within each simulated event, while maintaining the overall integrity of each extratropical system. The result is a stochastic catalog of potential storms with more realistic wind footprints.”

“AIR’s physical-stochastic approach combines NWP and stochastic techniques in a new way,” Dr. Fovell indicated. “The NWP component accurately constrains the stochastic while the stochastic component amply extends the physical. This unique approach results in a highly realistic view of the risk from extratropical cyclones.”

The model update also includes the addition of Windstorm Erwin to the historical event set. In January 2005, Erwin caused damaging winds in several Northern European countries. Denmark was hit particularly hard, partly as a result of the so-called “sting jet” phenomenon, which accelerates strong winds aloft down to the surface in the presence of convective (thunderstorm) cells.

“Extratropical cyclones are asymmetric storm systems that produce a variety of complex atmospheric phenomena including ‘sting jets,'” continued Tatge. “Using a three-dimensional NWP-based simulation of the storm, the AIR model successfully captured the impact of the extreme surface winds caused by Erwin’s sting jet. This further validates the realistic and accurate view of extratropical cyclone risk provided by the AIR model.”

AIR’s third generation European Extratropical Cyclone Model is available in Version 8.0 of CLASIC/2(TM) and CATRADER(R), AIR’s catastrophe risk management systems. For further information consult the Company’s Website at:

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