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Newsletter - Spring 2009

Current Research - Regional Greenhouse Gas Emissions

Airborne measurements of carbon monoxide

Sure, everybody talks about the weather but nodbody is willing to do anything about it. The same could have been said about climate change until the California Assembly passed its landmark “Global Warming Solutions Act” in 2006. The legislation sets specific emission limits on greenhouse gases (GHG) such as CO2, CH4, and N2O to an estimated 1990 level. But how do we know what the statewide or regional emissions of these gases are to begin with?

Emissions inventories that inform such policy decisions are based on ‘bottom-up’ accounting of all source activities, and are rarely, if ever, verified in the atmosphere. With an ever increasing interest in local, regional, and even global emissions it would behoove us to develop methods of quantifying surface sources of trace gases from direct observations in the atmosphere.

It was with this end in mind that Professor Ian Faloona, ATM graduate student Nenad Zagorac, and collaborators from Lawrence Berkeley National Lab (Marc Fischer) and NOAA’s Earth System Research Lab (Colm Sweeney) packed instrumentation into a small Cessna 210 at Napa Airport last March and took to the skies.

ATM graduate student Nenad Zagorac indicates that the preflight tests are complete and he is ready for take off.

Measuring GHGs up and down the delta and around the Sacramento metropolitan area, the group plans to help quantify major sources of greenhouse gases in the region. If the method proves successful it could become a mainstay of regulatory verification efforts.  

But CO is not officially a greenhouse gas, so why include the LAWR team? It turns out that because most GHGs have both ‘natural’ and human sources, it helps to be able to distinguish one from the other, and CO can aid in this because of its strong affiliation with fossil fuel combustion sources. As the team discovered this is not only true for fossil fuels. In fact, the original experiment was conducted in June of 2008 but the forest fires engulfing the state swamped the measurements and no “man-made” emissions were identifiable. The flights this Spring, however, were successful in observing human emissions throughout the region.  

View from the cockpit flying over the Sacramento Delta.

Image of CO (ppbv) measured in-flight up and down the delta.