Global climate change

Very strong Atlantic Hurricanes are intensifying faster than what they were 30 years ago

By Brett Anderson, AccuWeather senior meteorologist

5/09/2018, 12:45:22 PM

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Powerful hurricanes that intensify rapidly do so more strongly and rapidly today than they did 30 years ago, according to a new study.

The new research from the U.S. Department of Energy's Pacific NW National Laboratory and NOAA states that the main driver for this change is the natural climate cycle known as the Atlantic Multidecadal Oscillation or AMO.

Rapid intensification is defined by the study as a maximum wind increase of at least 29 mph within a 24-hour period.

The research team looked at 30 years worth of satellite hurricane data from 1986 to 2015.

The team did not find that rapid intensification is happening more often, but they did determine that there has been a sizable increase in the strength of fast-growing storms, which means that hurricanes are getting more powerful more quickly within a 24-hour period than what they were 30 years ago.

The researchers found that the average increase in wind speed over a 24-hour intensification event was about 13 mph more than it was 30 years ago.

A combination of sea surface temperatures, humidity, cloud characteristics, ocean heat content and wind shear played key roles in the hurricane intensification process.

However, the main factor for this change was the AMO, even more so than overall long-term global warming.

Key excerpt from the article......

The AMO governs how the temperature of the waters in the North Atlantic cycles between warmer and cooler, with each period typically lasting a decade or more. The cycling occurs for reasons scientists don't completely understand, but it has broad effects on the environment. For example, it plays a big part in determining the heat content of the oceans, an important factor powering hurricanes.

The AMO has been mostly in the positive phase since the late 1990s, which leads to a warming influence of the waters of the eastern and central Atlantic, especially east of the Lesser Antilles. This is also the same region where powerful hurricanes Irma, Jose and Maria rapidly intensified last year. Historically, rapid intensification has occurred more often in the western Atlantic, according to study co-author Karthik Balaguru.