Warming oceans can increase frequency of extreme rain storms

Rapid climate change, that is causing warming of the tropical oceans, could lead to a substantial increase in the frequency of extreme rain storms by the end of the century, say scientists from NASA.

The study team, led by Hartmut Aumann of NASA's Jet Propulsion Laboratory in California, found that extreme storms -- those producing at least 3 millimetres of rain per hour over a 25-kilometre area -- formed when the sea surface temperature was higher than about 28 degrees Celsius.

They also found that 21 per cent more storms form for every 1 degree Celsius that ocean surface temperatures rise.

Currently accepted climate models project that with a steady increase of carbon dioxide in the atmosphere (1 per cent per year), tropical ocean surface temperatures may rise by as much as 2.7 degrees Celsius by the end of the century.

If this were to happen, we could expect the frequency of extreme storms to increase by as much as 60 per cent by that time, the researchers explained.

Although climate models are not perfect, results like these can serve as a guideline for those looking to prepare for the potential effects a changing climate may have.

"Our results quantify and give a more visual meaning to the consequences of the predicted warming of the oceans," Aumann said.

"More storms mean more flooding, more structure damage, more crop damage and so on, unless mitigating measures are implemented."

For the study, published in the the Geophysical Research Letters journal, the team combed through 15 years of data acquired by NASA's Atmospheric Infrared Sounder (AIRS) instrument over the tropical oceans to determine the relationship between the average sea surface temperature and the onset of severe storms.

--IANS

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