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RESEARCH INTERESTS Atmospheric Chemistry, Biogeochemistry, and Climate Change Our goal is to get a better understanding of air quality, the composition of the atmosphere, and their impact on climate and stratospheric ozone under present, past, future and geoengineered conditions. We have been able to determine and quantify the concentrations of atmospheric oxidants and amount of dynamical mixing during NASA, NSF, NOAA and internationally sponsored airborne and shipborne research campaigns. These oxidants include hydroxyl, atomic chlorine, bromine monoxide and nitrate radicals. We use hydrocarbon and halocarbon measurements and other data along with empirical mathematical models and photochemical box models in these estimates. These results have been used to determine the sources and loss processes of climate relevant organic gases going into and out of the atmosphere. Some examples of the gases that are of interest to us are carbon monoxide, methane, isoprene, methyl bromide, and dimethyl sulfide (DMS). These gases have human-made and natural sources. Their distributions impact climate, stratospheric ozone and therefore the general circulation of the oceans and atmosphere. We have studied these gases under present, future and geo-engineered conditions to assess possible future climate under business as usual conditions and under scenarios with purposeful interventions, i.e. climate engineering. Although geo-engineering cannot by itself ward-off global warming, some strategies may allowing us more time to implement technological solutions aimed at reducing greenhouse gases. Much more research in this area is necessary in order to determine its possible efficacy and negative consequences. The solution to climate change will ultimately come when humankind has the ability to control greenhouse gases. We collaborate with the University of New Hampshire, University of California, Irvine and other groups nationally and internationally. We have recently begun working with Los Alamos National Laboratory on ocean and climate modeling. SELECTED FIELD PROJECTS Investigating atmospheric oxidants, especially halogen chemistry, and dynamics from changes in composition of nonmethane hydrocarbons and halocarbons and using detailed photochemical point (box) models during aircraft campaigns near the Azores in the North Atlantic (NSF sponsored ASTEX/MAGE),  over the Southern Ocean (NSF ACE-1), and the  Central Pacific (NASA GTE PEM-Tropics A).  These processes are important in understand  the lifetimes and degradation processes of radiatively important trace gases such as dimethyl sulfide (DMS). Quantifying anthropogenic versus natural emissions of stratospheric ozone depleting gases such as methyl bromide (CH3Br; global, Arctic, Southern Ocean, and in New Mexico) and gases important to climate from various sources.  Platforms include land, ship, mesocosms, and aircraft. Future, past and geo-engineered climates are studied using perturbation experiments simulating for example during SOFeX, The Southern Ocean Iron Fertilization Experiments (see also  reprint of PNAS paper) PeECE III, a mesocosm experiment studying the effects of future increased CO2 concentrations on ocean acidification and the perturbation to marine microorganisms and trace gas fluxes Air Quality - measuring and modeling constituents important to urban and regional air quality.  Areas studied while at New Mexico Tech include New England, Albert, Canada, Taiwan, and local areas.