Winnipeg Free Press > Latest News > Does New York's urban heat remotely warm Canadian winters and cool fall in Europe, Western US?

Latest News

The Canadian Press - ONLINE EDITION

Does New York's urban heat remotely warm Canadian winters and cool fall in Europe, Western US?

By: Seth Borenstein, The Associated Press

Posted: 01/27/2013 1:04 PM | Comments: 0 | Last Modified: 01/27/2013 2:09 PM

FILE - In this July 18, 2012 file photo, the Empire State, MetLife and Chrysler buildings are seen against a hazy backdrop in New York. Heat rising up from cities such as New York, Paris and Tokyo might be remotely warming up winters far away in some rural parts of Alaska, Canada, and Siberia. At least that�s what a surprising study suggests. (AP Photo/Mary Altaffer, File)

Enlarge Image

FILE - In this July 18, 2012 file photo, the Empire State, MetLife and Chrysler buildings are seen against a hazy backdrop in New York. Heat rising up from cities such as New York, Paris and Tokyo might be remotely warming up winters far away in some rural parts of Alaska, Canada, and Siberia. At least that�s what a surprising study suggests. (AP Photo/Mary Altaffer, File)

WASHINGTON - Heat rising up from cities such as New York, Paris and Tokyo might be remotely warming up winters far away in some rural parts of Alaska, Canada, and Siberia, a surprising study theorizes.

In an unusual twist, that same urban heat from buildings and cars may be slightly cooling the autumns in much of the Western United States, Eastern Europe and the Mediterranean, according to the study published Sunday in the scientific journal Nature Climate Change.

Meteorologists long have known that cities are warmer than rural areas, with the heat of buildings and cars, along with asphalt and roofs that absorb heat. That's called the urban heat island effect and it's long been thought that the heat stayed close to the cities.

But the study, based on a computer model and the Northern Hemisphere, now suggests the heat does something else, albeit indirectly. It travels about half a mile (800 metres) up into the air and then its energy changes the high-altitude currents in the atmosphere that dictate prevailing weather.

"Basically, it changes the flow." said Guang Zhang of the Scripps Institution of Oceanography in La Jolla, California. He wrote the paper with Aixue Hu at the National Center for Atmospheric Research in Boulder, Colorado.

This doesn't change overall global temperature averages significantly, unlike man-made greenhouse gases that cause global warming. Instead it redistributes some of the heat, the scientists said.

The changes seem to vary with the seasons and by region because of the way air currents flow at different times of the year. During the winter, the jet stream is altered and weakened, keeping cold air closer to the Arctic Circle and from dipping down as sharply, Hu explained.

The computer model showed that parts of Siberia and northwestern Canada may get, on average, an extra 1.4 degrees to 1.8 degrees Fahrenheit (0.8 to 1 degree Celsius) during the winter, which "may not be a bad thing," Zhang said. The effect isn't quite as much in northern North Dakota and Minnesota, where temperatures might be about half a degree warmer (0.3 degrees Celsius), and even less along the East Coast.

In contrast, Europe and the Pacific Northwest are cooled slightly in the winter from this effect. The jet stream changes prevent weather systems from bringing warmer air from the Atlantic to Europe and from the Pacific to the U.S. Northwest, thus cooling those areas a bit, he said.

The biggest cooling occurs in the fall, but Hu said he's not quite sure why that happens.

Several outside scientists said they were surprised by the study results, calling the work "intriguing" and "clever." But they said it would have to be shown in more than one computer model and in repeated experiments before they could accept this theory.

"It's an interesting and rationally carried out study," said David Parker, climate monitoring chief of the United Kingdom meteorology office. "We must be cautious until other models are used to test their hypothesis."

___

Seth Borenstein can be followed at http://twitter.com/borenbears

You can comment on most stories on winnipegfreepress.com. You can also agree or disagree with other comments. All you need to do is be a Winnipeg Free Press print or e-edition subscriber to join the conversation and give your feedback.

You can comment on most stories on winnipegfreepress.com. You can also agree or disagree with other comments. All you need to do is be a Winnipeg Free Press print or e-edition subscriber to join the conversation and give your feedback.

Have Your Say

New to commenting? Check out our Frequently Asked Questions.

Have Your Say

Comments are open to Winnipeg Free Press print or e-edition subscribers only. why?

Have Your Say

Comments are open to Winnipeg Free Press Subscribers only. why?

The Winnipeg Free Press does not necessarily endorse any of the views posted. By submitting your comment, you agree to our Terms and Conditions. These terms were revised effective April 16, 2010.

letters

Make text: Larger | Smaller

LATEST VIDEO

Traffic woes for Bombers fans at IGF

View more like this

Photo Store Gallery

  • JOE BRYKSA/WINNIPEG FREE PRESS Local-(Standup photo)- A wood duck swims through the water with fall refections in Kildonan Park Thursday afternoon.
  • Marc Gallant/Winnipeg Free Press. Local/Standup- BABY BISON. Fort Whyte Centre's newest mother gently nudges her 50 pound, female bull calf awake. Calf born yesterday. 25 now in herd. Four more calfs are expected over the next four weeks. It is the bison's second calf. June 7, 2002.

View More Gallery Photos

Poll

Which of these everyday math tasks could you tackle without a calculator? (Select all that apply)

View Results

View Related Story

Ads by Google