Characterizing Transport Processes of Ozone and Greenhouse Gases with Lidar

Observations of transport and mixing processes in the lower atmosphere are crucial for advancing our understanding of two pressing environmental challenges: predicting local and regional high ozone pollution episodes and quantifying large area greenhouse gas (GHG) emissions. Transport of ozone and its precursors plays an important role in determining whether or not a particular location will exceed the US National Ambient Air Quality Standard (NAAQS) for ozone. With ozone background levels rising and a lowering of the ozone NAAQS likely in the near future, the contribution of regional, long-range, and stratosphere-to-troposphere transport of ozone to high ozone pollution episodes will become increasingly important. Carbon sources and sinks determine atmospheric GHG concentrations and knowledge of their magnitude and distribution is critical for understanding climate change. Anthropogenic GHG emissions from large area sources such as cities or oil and gas fields are highly variable in space and time and currently not well characterized. There is a clear need to quantify these GHG fluxes to verify emission inventories and to assess the effectiveness of mitigation strategies to reduce GHG emissions.

Over the last several years we have conducted a number of studies in which we used differential absorption and Doppler lidars in combination with radar wind profilers and airborne in situ observations to characterize and quantify ozone and GHG fluxes. We will present measurements of a) the horizontal ozone flux from the Houston metropolitan area and its impact on air quality in adjacent rural regions, b) horizontal and vertical transport processes that lead to export of high ozone concentrations from the Los Angeles Basin, and c) methane fluxes downwind of oil and gas fields in Utah and Colorado.