An instrument aboard a seven-year-old satellite designed to help weather forecasters is proving to be a powerful new tool in climate monitoring by detecting the distribution of carbon dioxide in the atmosphere.
And it turns out, NASA scientists say — contrary to conventional thinking that the greenhouse gas is spread uniformly over the planet in a well mixed layer — the Atmospheric Infrared Sounder instrument detects a distinctly "lumpy" pattern of CO2 in the mid-troposphere some 3-7 miles up.
Scientists reported their findings this week at the annual meeting of the American Geophysical Union in San Francisco.
This NASA image shows the the monthly average of carbon dioxide in the middle of the troposphere made from data acquired by the infrared sounder during July 2009. These maps are the first-ever depictions of the global distribution of CO2 based solely on observations.
The observations show a large band of carbon dioxide undulating around the Northern Hemisphere, where most of it originates, but also a smaller band that researchers didn't expect to find around the Southern Hemisphere. They can follow big lumps of CO2 moving across the Pacific from Asia and across the Atlantic from North America, and around again.
NASA team leader Moustafa Chahine of the Jet Propulsion Laboratory in Pasadena said the data "can be used to develop better models to identify 'sinks,' regions of the Earth system that store carbon dioxide."
Andrew Dessler, a Texas A&M climate scientist studying the data, said the observations "have corroborated climate model predictions that the warming of our climate produced as carbon dioxide levels rise will be greatly exacerbated — in fact, more than doubled — by water vapor." This finding "essentially guarantees" warming "by several degrees Celsius" in the next century unless some unknown "strong negative feedback mechanism emerges elsewhere in Earth's climate system."