For additional Information:
Dr. John Christy, (205) 922-5763
[email protected]
Phillip Gentry, (205) 890-6414
[email protected]
Alabama is, like, cooler and cooler
Global warming notwithstanding, the average temperature in Alabama has
dropped by almost two degrees Fahrenheit over the past 65 years,
according to a new analysis of daily temperature reports from about 50
spots around the state.
"The 1930's to 1950's were warmer than the last 35 years," said Dr. John
Christy, an associate professor of atmospheric science at UAH. "Every
global climate model forecasts warming in the Southeastern United States,
but it's actually cooling."
In a project supported by the National Oceanic and Atmospheric
Administration's National Climate Data Center, Christy analyzed daily
temperature reports from towns, cities and crossroads across the state,
including such metropolitan sites as Aliceville, Demopolis and Marion
Junction.
"When you use daily data, you find things like a mean bias between sites,
such as a 4.08 degree (Fahrenheit) difference between Selma and Clanton,"
Christy said. "There is actually a seasonal cycle to that. Clanton is 6
degrees warmer in the winter, but only 2 degrees warmer in the summer.
"That's an indication that there are buildings or parking lots near the
Clanton thermometer which keep winter temperatures a little warmer than
they would be otherwise. There is a trend in this difference, which shows
that 'urbanization' has been slowly developing around Clanton's thermometer."
Christy used mean biases derived from comparing several regional sites to
pick up artificial biases caused by such things as urban growth, changes
in the thermometer site or changes in equipment.
By comparing daily temperature readings from a particular site against
readings from a large number of surrounding cities and towns, Christy
could determine whether a cooling trend, for instance, was real or caused
by a tree which finally grew large enough to shade a National Weather
Service thermometer. He also isolated real warming events from warming
caused by new parking lots and buildings.
Raw data since 1928 show a statewide cooling trend of approximately 0.15
degrees Celsius per decade, Christy said. He intends to take the analysis
back to 1890, where unadjusted data indicate Alabama's cooling trend has
persisted for more than 100 years.
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(EDITORS: An earlier study by Dr. John Christy and a former California state
climatologist using suburban and rural weather station temperature data
found no trace of "global warming" in California. Christy is attending
the American Meteorological Society's convention in Long Beach,
California, this week -- Feb. 3-7 -- at the Long Beach Convention Center.)
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