jimgandy
Registered: 11/27/08
Posts: 110
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| | 01/27/10 at 12:37 AM | Reply with quote | #1 |
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There has long been a discussion of the effects of global warming on hurricanes. Some studies point to an increase in intense hurricanes while others argue that there would be fewer hurricanes due to increased wind shear environments.
A study published in the current edition of Science (22 January 2010) uses a recent modeling technique called "double-downscaling". The results seem to converge on some earlier studies, but there is still work to be done. One interesting conclusion from the study is that the authors do not believe that any signal from warming should be observable yet.
An overview of the report by Richard A. Kerr is available to members of AAAS at: http://www.sciencemag.org/cgi/content/short/327/5964/399 .
The abstract of the report:
Modeled Impact of Anthropogenic Warming on the Frequency of Intense Atlantic Hurricanes Morris A. Bender,1,* Thomas R. Knutson,1 Robert E. Tuleya,2 Joseph J. Sirutis,1 Gabriel A. Vecchi,1 Stephen T. Garner,1 Isaac M. Held1 Several recent models suggest that the frequency of Atlantic tropical cyclones could decrease as the climate warms. However, these models are unable to reproduce storms of category 3 or higher intensity. We explored the influence of future global warming on Atlantic hurricanes with a downscaling strategy by using an operational hurricane-prediction model that produces a realistic distribution of intense hurricane activity for present-day conditions. The model projects nearly a doubling of the frequency of category 4 and 5 storms by the end of the 21st century, despite a decrease in the overall frequency of tropical cyclones, when the downscaling is based on the ensemble mean of 18 global climate-change projections. The largest increase is projected to occur in the Western Atlantic, north of 20°N.
2 Center for Coastal Physical Oceanography, Old Dominion University, 4111 Monarch Way, Norfolk, VA 23508, USA. * To whom correspondence should be addressed. E-mail: Morris.Bender@noaa.gov
Again, the full report is available to members of AAAS at:
http://www.sciencemag.org/cgi/content/full/327/5964/454
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jimgandy
Registered: 11/27/08
Posts: 110
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| | 02/24/10 at 10:31 PM | Reply with quote | #2 |
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A new study was recently published in Nature Geoscience which is a companion to the article above. Here is a link to the USA Today article on the study:
http://www.usatoday.com/tech/news/2010-02-22-Hurricanes19_ST_N.htm
The abstract from Nature Geoscience is as follows:
Nature Geoscience
Published online: 21 February 2010 | doi:10.1038/ngeo779 Tropical cyclones and climate changeThomas R. Knutson1, John L. McBride2, Johnny Chan3, Kerry Emanuel4, Greg Holland5, Chris Landsea6, Isaac Held1, James P. Kossin7, A. K. Srivastava8 & Masato Sugi9
AbstractWhether the characteristics of tropical cyclones have changed or will change in a warming climate — and if so, how — has been the subject of considerable investigation, often with conflicting results. Large amplitude fluctuations in the frequency and intensity of tropical cyclones greatly complicate both the detection of long-term trends and their attribution to rising levels of atmospheric greenhouse gases. Trend detection is further impeded by substantial limitations in the availability and quality of global historical records of tropical cyclones. Therefore, it remains uncertain whether past changes in tropical cyclone activity have exceeded the variability expected from natural causes. However, future projections based on theory and high-resolution dynamical models consistently indicate that greenhouse warming will cause the globally averaged intensity of tropical cyclones to shift towards stronger storms, with intensity increases of 2–11% by 2100. Existing modelling studies also consistently project decreases in the globally averaged frequency of tropical cyclones, by 6–34%. Balanced against this, higher resolution modelling studies typically project substantial increases in the frequency of the most intense cyclones, and increases of the order of 20% in the precipitation rate within 100 km of the storm centre. For all cyclone parameters, projected changes for individual basins show large variations between different modelling studies.
- Geophysical Fluid Dynamics Laboratory/NOAA, 201 Forrestal Road, Princeton, New Jersey 08542, USA
- Centre for Australian Weather and Climate Research, Melbourne 3001, Australia
- Guy Carpenter Asia-Pacific Climate Impact Centre, City University of Hong Kong, Kowloon, Hong Kong, China
- Program in Atmospheres, Oceans, and Climate, Massachusetts Institute of Technology, Room 54-1620 MIT, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA
- National Center for Atmospheric Research, Boulder, Colorado, USA
- National Hurricane Center/NWS/NOAA, 11691 SW 17th Street, Miami, Florida 33165, USA
- National Climatic Data Center/NOAA, 1225 W Dayton Street, Madison, Wisconsin 53706, USA
- India Meteorological Department, Shivajinagar, Pune 411005, India
- Research Institute for Global Change, JAMSTEC, 3173-25 Showa-machi, Kanazawa-ku, Yokohama, 236-0001 Kanagawa, Japan.
Correspondence to: Thomas R. Knutson1 e-mail: Tom.Knutson@noaa.gov You may be interested at looking at Dr. Kerry Emanuel's presentation at the Presidential Forum in San Antonio, 2007:
http://ams.confex.com/ams/87ANNUAL/techprogram/paper_121416.htm
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