Mapping the Air

New maps from NASA's climate-monitoring satellite Aura are showing, for the first time, high-resolution views of the global ebb and flow of important atmospheric pollutants and ice particles in clouds, researchers announced at the American Geophysical Union meeting in San Francisco on Dec. 8.

The pictures have already enabled scientists to strengthen the correlation between combustion-produced carbon monoxide and ozone, which is a toxic pollutant in the troposphere, the lowest level of the atmosphere. This level of monitoring, ongoing since Aura was launched 18 months ago, is also extremely important for improving the accuracy and predictability of climate models, they said.

Carbon monoxide is known as a good marker of pollution. New data from Aura's tropospheric emission spectrometer now reveal an "ozone pollution belt" at northern midlatitudes. Scientists believe industrial emissions from Europe and Asia are carried across the globe via trade winds.

"This provides the first test of models that have argued for the intercontinental transport of ozone," said Daniel J. Jacob, atmospheric chemistry professor at Harvard University.

Aura is also tracking nitric acid, the so-called "graveyard of nitrogen oxides" in the upper troposphere, showing "hot spots" over areas of combustion in North America, Europe, and Africa.

Ice clouds, which reflect radiation, play a role in both cooling and heating Earth. But the global distribution of cloud ice has been largely unknown, and climate models for the Intergovernmental Panel on Climate Change differ by as much as a factor of 20 in their estimation of a global average.

Now, measurements from Aura's microwave limb sounder provide the first clear picture of solid ice in clouds, said Duane E. Waliser, an atmospheric scientist at the Jet Propulsion Laboratory in Pasadena, Calif. The data should help tame the wild variance of the current models. "I can almost guarantee that in five years, the uncertainty [in the models] will be reduced," Waliser said.

Aura's Ozone Tracking Instrument has been monitoring ozone levels over Europe, producing maps that are now updated every few hours. The maps show clearly that in Europe, tropospheric ozone levels are at their lowest on Sunday afternoons.