88th Annual Meeting (20-24 January 2008)

Wednesday, 23 January 2008
Using Gumbel distribution to estimate return intervals for extreme wind events for Alaska and Hawaii
Exhibit Hall B (Ernest N. Morial Convention Center)
O. Francis-Chythlook, Univ. of Alaska, Fairbanks, AK; and D. E. Atkinson
The Gumbel, or extreme value, distribution has become a standard for categorizing the behavior of long-tail processes with low-frequency high-magnitude events of interest. In this study extreme wind events are categorized for Alaska and Hawaii and return intervals for specified wind magnitudes are extracted. A Gumbel distribution is fitted to observational hourly wind data. From this curve location and scale parameters are extracted. These are fed into an algorithm that inverts the distribution, allowing it to be solved for return interval. Return interval values for strong wind events are estimated and shown. The return values represent wind speed thresholds that will be exceeded on average once every return period. This study demonstrates that large values for the Gumbel scale and location parameters give a higher T-year return value, meaning a stronger wind event for a given return frequency.

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