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[school-discuss] global warming ---> it's a good bit cooler than the government models assumed
August 28, 2002
FRIGID SOUTH POLE ATMOSPHERE REVEALS FLAW IN GLOBAL CIRCULATION MODELS
Atmospheric measurements made at Earth's geographic poles provide a convenient
way of validating and calibrating global circulation models. Such
measurements also might provide some of the first conclusive evidence of
global change in the middle and upper atmospheres. But new data shows that
the current models are wrong: Temperatures over the South Pole are much
colder in winter than scientists had anticipated.
As reported in the Aug. 28 issue of Geophysical Research Letters, scientists
have found that temperatures during mid-winter in the stratopause and
mesopause regions at the South Pole are about 40-50 degrees Fahrenheit colder
than model predictions.
"With the reduced down-welling, the predicted mesopause temperature near 60
miles altitude decreased from about minus 120 degrees Fahrenheit to about
minus 140 degrees Fahrenheit, in better agreement with our measurements for
mid-winter conditions," Gardner said. "In the stratopause region, the
predicted temperature decreased from about 35 degrees Fahrenheit to about 12
degrees Fahrenheit, also in better agreement with our measurements."
The recent measurements establish a baseline for polar temperatures, which can
then be compared against future changes as greenhouse gases continue to
accumulate, Gardner said. "The measurements also show that we have a flaw in
some of our global atmospheric circulation models. Now we can go back and
improve those models to better predict the temperatures in the middle and
upper atmospheres throughout both hemispheres."
The National Science Foundation funded the work.
This text derived from http://www.news.uiuc.edu/scitips/02/0828southpole.html