ESRL Quarterly Newsletter - Spring 2010

Soarin' Over California

CalNex examines contributors to region's air quality, climate change challenges

The air over California will be scrutinized from every angle this spring, as ESRL scientists and colleagues make the most detailed analysis yet of factors influencing air quality and climate change in the state.

From airplane, ship, satellite, and tall tower, ESRL scientists and colleagues (led by ESRL's Chemical Sciences Division) will examine California's atmosphere with an arsenal of instruments. Their scientific goals include understanding the origins of pollutants and greenhouse gases, and the transport, reactions, and eventual fates of those particles and gases.

CalNex (for the “nexus” of climate change and air quality) should generate information that will help decision makers understand the complicated interactions of air quality and climate—because policies to address one are likely to influence the other, as well.

“The goal is to provide decision makers with the information they need for developing “win-win” strategies that help both climate and air quality,” said A.R. Ravishankara, Director of the Chemical Sciences Division.

CalNex draws expertise from across NOAA—from all ESRL divisions, the Pacific Marine Environmental Laboratory, the Air Resources Laboratory, the National Centers for Environmental Prediction—and academic and international collaborators.

Tom Ryerson (Chemical Sciences Division) described CalNex during the American Geophysical Union meeting in December, with exhaustive lists of partners (foremost, the California Air Resources Board), instruments, and platforms.

“This is about understanding how ozone and secondary organic aerosols form from precursors, the spatial and temporal patterns of greenhouse gas emissions, methane emissions from rice paddies in the Northern Sacramento Valley, the sulfur budget of the LA Basin…,” Ryerson said. “It's a kitchen sink approach, but an integrated kitchen sink.”

Overall, CalNex scientists will quantify sources of diverse emissions, from the precursors of lung-damaging ozone and haze to the greenhouse gas carbon dioxide. The field campaign will track the chemical transformations of those emissions, including sunlight-driven and nighttime chemistry. And CalNex will follow the transport and mixing of emissions, to put those observations into context.

Mission scientists will also study the properties and heating effects of atmospheric particles and their interactions with clouds, and will develop and evaluate models used to understand regional climate and air quality.

In its comprehensive exploration of atmospheric chemistry, CalNex resembles two other regional, intensive campaigns led by the Chemical Sciences Division: The Texas Air Quality study of 2006, and the New England Air Quality study of 2002. Both field campaigns generated information that proved important for policy makers as well as scientists seeking to understand atmospheric processes.

In Texas, for example, ESRL scientists and colleagues found that reactive gases leaking from Houston's petrochemical refineries were an unexpectedly significant contributor to regional air quality problems. Regulators changed their approach in response to that discovery, at an estimated savings of 65,000 jobs in the state, and $10 billion between 2006 and 2010.