29 October 2007
A paper by CSD scientists and their colleagues in ESRL/GMD and other institutions has been selected for the OAR Outstanding Scientific Paper Award in the climate category. Owen Cooper (CIRES/CSD) was lead author of the paper "Large upper tropospheric ozone enhancements above midlatitude North America during summer: In situ evidence from the IONS and MOZAIC ozone measurement network" published in 2006 in Journal of Geophysical Research.
Background: In the upper troposphere, ozone acts as a greenhouse gas and hence is relevant to climate. Cooper et al. have found unexpectedly high levels of summertime ozone in the upper troposphere 10-11 kilometers above eastern North America, not attributable to either the high amounts of ozone pollution at Earth's surface or the higher ozone levels in the stratosphere. The authors investigated the cause of these enhancements, which can nearly double the amount of upper tropospheric ozone above the region. It was found that a natural factor – the emission of nitrogen oxides from lightning – acts in concert with the generally higher background levels of ozone precursor compounds in today's polluted atmosphere to produce most of the upper-tropospheric ozone enhancement. This ozone enhancement with a strong natural component contributes to the radiation budget on the regional scale. Further studies are required to gauge potential impacts on surface heating of the southeastern United States and regions downwind.
Significance: The paper shows that lightning and pollutants combine to cause ozone enhancements in the summertime upper troposphere in the eastern U.S. The process could have implications for surface heating and hence the research is important to climate. The research contributed to NOAA's Climate Forcing Program within the Climate Goal.
Owen R. Cooper, Andreas Stohl, Michael Trainer, Anne M. Thompson, Jacquelyn C. Witte, Samuel J. Oltmans, Gary Morris, Kenneth E. Pickering, James H. Crawford, Gao Chen, Ronald C. Cohen, Timothy H. Bertram, Paul J. Wooldridge, Anne E. Perring, William H. Brune, John Merrill, Jennie L. Moody, David Tarasick, Philippe Nédélec, Gerry Forbes, Michael J. Newchurch, Frank J. Schmidlin, Bryan J. Johnson Solene Turquety, Steven L. Baughcum, Xinrong Ren, Fred. C. Fehsenfeld, James F. Meagher, Nicole Spichtinger, Clyde C. Brown, Stuart A. McKeen, I. Stuart McDermid, and Thierry Leblanc, Large upper tropospheric ozone enhancements above midlatitude North America during summer: In situ evidence from the IONS and MOZAIC ozone measurement network, Journal Of Geophysical Research, doi:10.1029/2006JD007306, 2006.