Number of extreme wave events exceeding 8m in oceanic regions, 2008–15

Extreme wave indexes estimate the occurrence of extreme wave events in coastal and oceanic waters. Extreme wave indexes estimate the number of times a significant wave height exceeds one of three threshold values for at least 12 hours in 24 marine regions. The three wave-height thresholds are four metres, six metres, and eight metres. This indicator estimates the exceedances of a wave-height threshold for each year from 2008 to 2015 in oceanic regions. Significant wave height is a measure of the ‘typical’ wave height in a place over a time period. It is four times the standard deviation of the water surface if, for example, you were to measure water moving up and down a jetty piling for an hour. The largest individual wave will typically have a height around twice the significant wave height. We use three wave-height thresholds because of the regional variation in extreme wave events. In general, the north experiences less exposure to consistently strong winds, and the waves generated by them, than the south. Four-metre tall waves are considered extreme in the northern-most parts of New Zealand but are more common in the south. For the southern-most parts of New Zealand, eight-metre waves better represent extreme wave events. This dataset relates to the number of extreme wave events exceeding the eight metre threshold in oceanic regions.

Data and Resources

Additional Info

Field Value
Author Ministry for the Environment
Maintainer Ministry for the Environment
Maintainer Email Ministry for the Environment
Created 2016-10-19T22:08:53.759140Z
Date modified 2016-10-26T01:33:41.519071Z
Language English
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Source Identifier
Record created February 2, 2020, Last Updated April 2, 2021