[Vision2020] Geophysical Research Letters: New study: A warming world will further intensify extreme precipitation events

[Ted Moffett]

Not exactly groundbreaking news, given this has been predicted for decades;
but this study offers even more science to support this predication.

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http://www.noaanews.noaa.gov/stories2013/20130403_ncdcextremeprecipitationstudy.html
New study: A warming world will further intensify extreme precipitation
events

April 4, 2013

According to a newly-published NOAA-led study in *Geophysical Research
Letters, *as the globe warms from rising atmospheric concentrations of
greenhouse gases, more moisture in a warmer atmosphere will make the most
extreme precipitation events more intense.

The study, conducted by a team of researchers from the North Carolina State
University’s Cooperative Institute for Climate and Satellites-North
Carolina (CICS-NC), NOAA’s National Climatic Data
Center<http://www.ncdc.noaa.gov/>(NCDC), the Desert Research
Institute, University of Wisconsin-Madison, and
ERT, Inc., reports that the extra moisture due to a warmer atmosphere
dominates all other factors and leads to notable increases in the most
intense precipitation rates.

The study also shows a 20-30 percent expected increase in the maximum
precipitation possible over large portions of the Northern Hemisphere by
the end of the 21st century if greenhouse gases continue to rise at a high
emissions rate.

“We have high confidence that the most extreme rainfalls will become even
more intense, as it is virtually certain that the atmosphere will provide
more water to fuel these events,” said Kenneth Kunkel, Ph.D., senior
research professor at CICS-NC and lead author of the paper.

The paper looked at three factors that go into the maximum precipitation
value possible in any given location: moisture in the atmosphere, upward
motion of air in the atmosphere, and horizontal winds. The team examined
climate model data to understand how a continued course of high greenhouse
gas emissions would influence the potential maximum precipitation. While
greenhouse gas increases did not substantially change the maximum upward
motion of the atmosphere or horizontal winds, the models did show a 20-30
percent increase in maximum *moisture* in the atmosphere, which led to a
corresponding increase in the maximum precipitation value.

The findings of this report could inform “design values,” or precipitation
amounts, used by water resource managers, insurance and building sectors in
modeling the risk due to catastrophic precipitation amounts. Engineers use
design values to determine the design of water impoundments and runoff
control structures, such as dams, culverts, and detention ponds.

“Our next challenge is to translate this research into local and regional
new design values that can be used for identifying risks and mitigating
potential disasters. Findings of this study, and others like it, could lead
to new information for engineers and developers that will save lives and
major infrastructure investments,” said Thomas R. Karl, L.H.D., director of
NOAA’s NCDC in Asheville, N.C., and co-author on the paper.

The study, *Probable Maximum Precipitation (PMP) and Climate
Change*<http://www.noaanews.noaa.gov/exit.html?http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1002%2Fgrl.50334%2Fabstract>,
can be viewed online.

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Vision2020 Post: Ted Moffett
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