
Hot Tower in Hurricane Bonnie 1998. Altitude of clouds are exaggerated
A "hot tower" is a tropical
cumulonimbus cloud that penetrates the
tropopause, i.e. it reaches out of the lowest layer of the atmosphere, the
troposphere, into the
stratosphere. In the tropics, the tropopause typically lies at least 15 km above sea level. These towers are called "hot" because they rise high due to the large amount of latent heat released as water vapor condenses into liquid.
The "hot tower hypothesis" was proposed in 1958 by
Joanne Malkus Simpson and
Herbert Riehl. Prior to 1958, the mechanism driving the global-scale circulation pattern called
Hadley cells was poorly understood. Simpson and Riehl proposed that the energy feeding these enormous
convective cells was supplied by the release of
latent heat during condensation of warm, moist air in the centers of
tropical storms, including
hurricanes.
Recently the
National Aeronautics and Space Administration (NASA) has discovered that these hot towers appear when the hurricane is about to intensify. A particularly tall hot tower rose above
Hurricane Bonnie in August 1998, as the storm intensified before striking
North Carolina,
United States. Bonnie caused more than $1 billion damage and three deaths, according to the
National Oceanic and Atmospheric Administration and the
National Hurricane Center.
See also
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Tropical cyclone
External links
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Hurricane Multimedia Gallery. - A Hurricane Multimedia page.
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Hurricane 2005 A Hurricane Resource Site - Hurricane Resources
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UCAR slides: "Hot Towers and Hurricanes: Early Observations, Theories and Models"
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EO Library: Joanne Simpson: Hot Tower Hypothesis