On Mar 8, 10:14 am, Tommy News <tommysn...@gmail.com> wrote:
> Climate Change: Midwest Tornadoes: Record Week Of Twisters Hit
> America's Heartland, Warmest February
>
> By Sharon Begley
>
> NEW YORK, March 5 (Reuters) - When at least 80 tornadoes rampaged
> across the United States, from the Midwest to the Gulf of Mexico, last
> Friday, it was more than is typically observed during the entire month
> of March, tracking firm AccuWeather.com reported on Monday.
>
> According to some climate scientists, such earlier-than-normal
> outbreaks of tornadoes, which typically peak in the spring, will
> become the norm as the planet warms.
>
> "As spring moves up a week or two, tornado season will start in
> February instead of waiting for April," said climatologist Kevin
> Trenberth of the National Center for Atmospheric Research.
>
> Whether climate change will also affect the frequency or severity of
> tornadoes, however, remains very much an open question, and one that
> has received surprisingly little study.
>
> "There are only a handful of papers, even to this day," said
> atmospheric scientist Robert Trapp of Purdue University, who led a
> pioneering 2007 study of tornadoes and climate change.
>
> "Some of us think we should be paying more attention to it," said
> atmospheric physicist Anthony Del Genio of the Goddard Institute for
> Space Studies, part of NASA.
>
> The scientific challenge is this: the two conditions necessary to
> spawn a twister are expected to be affected in opposite ways. A warmer
> climate will likely boost the intensity of thunderstorms but could
> dampen wind shear, the increase of wind speed at higher altitudes,
> researchers say.
>
> Tomorrow's thunderstorms will pack a bigger wallop, but may strike
> less frequently than they have historically, explained Del Genio.
>
> "As we go to a warmer atmosphere, storms - which transfer energy from
> one region to another - somehow figure out how to do that more
> efficiently," he said. As a result, thunderstorms transfer more energy
> per outbreak, and so have to make such transfers less often.
>
> In a 2011 paper, Del Genio calculated that, "especially in the central
> and eastern United States, we can expect a few more days per month
> with conditions favorable to severe thunderstorm occurrence" by the
> latter part of this century if the global climate grows warmer.
>
> Indeed, the world has been experiencing more violent storms since
> 1970, the Intergovernmental Panel on Climate Change reported in its
> most recent assessment.
>
> EXTENDING TORNADOES' PATH
>
> Purdue's Trapp and colleagues got a similar result in their 2007
> study, which they confirmed in research published in 2009 and 2011.
> "The number of days when conditions exist to form tornadoes is
> expected to increase" as the world warms, he said.
>
> In addition, they found, regions near the Gulf of Mexico and Atlantic
> coasts not normally associated with tornadoes will experience
> tornado-making weather more frequently. They projected a doubling in
> the number of days with such conditions in Atlanta and New York City,
> for instance.
>
> More powerful thunderstorms would be expected to produce more
> tornadoes, but wind shear could prove a mitigating factor.
>
> Because climate change is not uniform, Del Genio wrote in the 2011
> paper, "in the lower troposphere, the temperature difference between
> low and high latitudes decreases as the planet warms, creating less
> wind shear."
>
> Other scientists are not so sure, and they see a surge in tornadoes
> last year as ominous. April 2011 was the most active tornado month on
> record, with 753, according to the National Oceanic and Atmospheric
> Administration (NOAA), compared to the previous record of 267 in April
> 1974.
>
> "I have no doubt that there will be many times when wind shear is
> plenty strong to create a tornado," said Trenberth.
>
> That is what Trapp's team concluded in their 2007 study. "Over most of
> the United States," they wrote, the increase in the power of
> thunderstorms will "more than compensate for the relative decreases in
> shear."
>
> As a result, "the environment would still be considered favorable for
> severe convection" of the kind that creates tornadoes.
>
> From March to May the projected increase in severe storms is "largest
> over a 'tornado-alley'-like region extending northward from Texas,"
> Trapp found. From June through August, the eastern half of the country
> is projected to experience such an increase.
>
> If there are more days in the future when wind shear is too weak to
> produce a tornado from a thunderstorm, said Trenberth, then "the
> frequency of tornadoes may decrease but the average intensity might
> increase. You could have a doozy of an outbreak, and then they could
> go away for a while."
>
> On average, about 800 tornados are reported annually in the United
> States. About 70 percent are "weak," finds NOAA, with winds less than
> 110 mph (177 kph) . Just under 29 percent are "strong," with winds
> between 110 and 205 mph (177 and 329 kph) . Only 2 percent of all
> tornadoes are what NOAA characterizes as "violent," with winds in
> excess of 205 mph (329 kph) , but they account for 70 percent of all
> twister deaths. (Editing by Michele Gershberg and Sandra Maler)
>
> More:http://www.huffingtonpost.com/2012/03/06/midwest-tornadoes-record-wee...
>
> --
> Together, we can change the world, one mind at a time.
> Have a great day,
> Tommy
>
> --
> Together, we can change the world, one mind at a time.
> Have a great day,
> Tommy
--
Thanks for being part of "PoliticalForum" at Google Groups.
For options & help see http://groups.google.com/group/PoliticalForum
* Visit our other community at http://www.PoliticalForum.com/
* It's active and moderated. Register and vote in our polls.
* Read the latest breaking news, and more.
No comments:
Post a Comment