Meteorological offices worldwide forecast ocean wave heights for the shipping and fisheries industry. In the United States, NOAA's National Weather Service provides the wave forecasts. Just like in weather forecasting, scientists run numerical models to make these predictions.
Wind blowing across the ocean surface generates most ocean waves. Waves just transmit energy; the water itself does not travel with the passing of the energy. The water particles simply move up and backwards, up and forward, down and forward and finally down and backward with the passing of a wave form. This motion gives ocean waves their name: orbital waves.
This movie shows wave height calculations of one of the most commonly used predictive models, called 'WAVEWATCH III®'. WAVEWATCH III® uses global and regional wind data to calculate wind-driven waves every three hours.
We measure wave height as the distance between the wave crest and trough. Note that waves come in fields containing a large variety of heights; the wave height distribution. To describe the wave field with a single number scientists use the 'Significant Wave Height'. The Significant Wave Height is the mean wave height of the one-third highest waves in the wave field. This measure is the closest to what a sailor on a ship would estimate as 'the average wave height'. Apparently our eyes are drawn to see the larger waves. This movie shows the significant wave height every 3 hours, worldwide for the year 2012.
Educational materials have been developed for this dataset, including a few PowerPoint slides, that can be used on a supplementary screen while viewing the dataset on Science On a Sphere®. Also, a discussion-based lesson plan can be used to facilitate student learning about wave heights.
During the northern hemisphere winter, the most intense wave activity is located in the central North Pacific south of the Aleutian Islands, and in the central North Atlantic south of Iceland.
During the southern hemisphere winter, intense wave activity circumscribes the pole at around 50 degrees S, with 5 m significant wave heights typical in the southern Indian Ocean.
In the summer and early fall, it is peak hurricane season in the Atlantic Ocean, because the temperature difference between the continent and ocean is the largest. The 2012 Atlantic hurricane season was very active; there were 19 named tropical storms and hurricanes. The earliest storms happened already in May 2012.
Hurricane Sandy was the deadliest and costliest hurricane of 2012, it formed on October 22nd 2012. In total, the 2012 storms caused 355 known fatalities and nearly $71 billion in damage.
The highest predicted significant wave height was 17m in 2012, but much higher waves occur occasionally in the open ocean.