|Predicting Major Weather Disasters -- Inside Science
Reported August 2006
BACKGROUND: At the National Center for Atmospheric Research in Boulder, Colorado, scientists say small islands and large coastal cities are more vulnerable to severe weather disasters. For instance, Boston, New York and Washington, D.C., may be due for deadly hurricanes, while Michigan could experience a tsunami caused by a landslide, and the Midwest could experience an earthquake. Scientists are employing all kinds of new technologies to help them better predict all types of natural disasters.
EFFECTS OF CLIMATE CHANGE: If it seems like hurricanes are becoming more frequent and severe, that's because they are, thanks to rising air and water temperatures around the world, which make it easier for hurricanes to form. Some scientists attribute this to global warming and human activity, such as deforestation and greenhouse gas emissions. Others think it is due to natural changes deep in the Atlantic, part of a natural cycle that shifts every 40 years to 60 years.
PHASED ARRAY RADAR: Adapted from the SPY-1 radar technology used by the U.S. Navy to spot severe weather while ships are at sea, phased array radar uses multiple beams and frequencies to reduce scan time to less than one minute, enabling faster updates on weather conditions. This technology may help forecasters in the future provide earlier warnings for severe and hazardous weather; for example, it could increase the average lead time for tornado warnings beyond the current average of 11 minutes.
ABOUT TORNADOES: A tornado begins with a thunderstorm cloud, which can build up a lot of energy. If this energy creates a particularly strong updraft of air, it will form a vortex, much like how a whirlpool forms in a bathtub that is draining. The air is pulled toward the center in a spiral, forming a tornado under the thundercloud. Wind speeds can reach 200 mph to 300 mph, and if the dangling vortex touches ground, the combination of the whirling wind's speed, the updraft, and pressure differences can cause severe damage. The path of a tornado is determined by the path of the parent thundercloud, but it will often appear to hop (called a "jumper"). This occurs when the vortex is disturbed, causing it to collapse momentarily and reform.
The American Geophysical Union and the American Meteorological Society contributed to the information contained in the TV portion of this report.
If you would like more information, please contact:
National Center for Atmospheric Research
Boulder, CO 80305
American Geophysical Union
Washington, DC 20009-1277
The American Meteorological Society
Boston, MA 02108-3693
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