Pick a day during the past 138 years -- during the "Dust Bowl" say, or the 1938 New York Hurricane, or the blizzards in the Prairies in 1899 -- and now scientists can tell you pretty much what the atmosphere was up to at the time.
Using measurements of air pressure on land and sea going back into the 19th century and powerful supercomputers, a big international team of researchers have built a set of data that describes what Earth's atmosphere -- from the surface to the Jet Stream -- has been doing every six hours since 1871.
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The completion of the big 20th Century Reanalysis Project, which consumed millions of supercomputing hours at the U.S. Department of Energy science centers in California and Tennessee, allows scientists to look back into past weather events and see details they could not have imagined just a few years ago.
"It's like we have a time machine," says project leader Gilbert P. Compo, a climate scientist at the University of Colorado and the National Oceanic and Atmospheric Administration's Earth Systems lab in Boulder. A detailed description of the project appears in the current issue of the Quarterly Journal of the Royal Meteorological Society.
"We can now put into context this year's and last year's cold winters in the US Northeast and compare with the great Arctic outbreaks, such as those during the winter of 1899," Compo told Discovery News in an email. "Any historical storm, or series of storms, can be examined."
The database dates back to the 1870s, when soldiers of the U.S. Signal Corps first began systematically recording weather observations, and employs the records kept by 19th Century sea captains and explorers and medical doctors who were interested in the health effects of different climates.
The database will prove especially important in evaluating and improving the performance of climate models -- the workhorses of climate science.
As Compo put it:
"With this new dataset, we will be able to compare the historical weather and climate variability with climate model simulations of the late 19th to 21st centuries to determine those regions where we have confidence in the simulations. How well do models capture the kinds of extreme weather that we see in the historical record?"
IMAGE: Bulletin of the American Meteorological Society
Tags: Climate Change, Hurricanes, Meteorology, Weather
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