In this project, ozone (O3), NOx (NO+NO2), peroxyacetyl nitrate (PAN), non-methane hydrocarbons (NMHC), and carbon monoxide (CO) will be measured continuously over two full summers at the Pico mountain observatory in the Azores, in order to study transport events over a range of transport altitudes and pathways. To identify and attribute pollution transport events, FLEXPART particle dispersion model simulations of the transport of anthropogenic and boreal wildfire emissions to Pico will be conducted, and all events with observed anthropogenic impacts and minimal boreal fire impacts will be analyzed. Tropospheric O3, CO, and NO2 from the TES, OMI, and SCIAMACHY satellite sensors will be analyzed to assess the importance of the sampled events relative to the total column. Data will be analyzed in conjunction with GEOS-Chem chemical transport model (CTM) simulations to evaluate the ability of the CTM to simulate observed absolute and relative enhancements in measured species and to probe the consistency between observations and simulated photochemistry and mixing. New techniques will be used that combine high-resolution FLEXPART simulations with CTM output to obtain a semi-Lagrangian sampling of CTM simulations in pollution transport events. By analyzing multiple events over two summer seasons, the data will be used to quantify the contribution of such events to large-scale impacts of continental outflow on O3 and O3 precursors. This work will lead to reduced uncertainties in estimates of the impacts of anthropogenic and boreal fire emissions on tropospheric O3. It will provide new information on variability in remote lower free tropospheric O3 and PAN resulting from inter-annual variability in boreal fire activity. This project will contribute to teaching and training by providing a doctoral research topic for one graduate student as well as an undergraduate research project; through the sharing of research findings with high school teachers in the Azores; and through a web site. It will enhance research infrastructure by maintaining the Pico station during a period of transition to a permanent Global Atmosphere Watch (GAW) station. A Pico GAW station would be a valuable resource for the atmospheric science community for long-term monitoring of atmospheric composition and trans-Atlantic pollution transport, and as a base for research intensives.

Project Report

This project had several major outcomes. First and foremost was the collection of 4 years of measurement data at the remote mountaintop station. These measurements focused on the formation of ozone, which is an EPA regulated pollutant, due to its negative impacts on human health, and also an important greenhouse gas. The suite of measurements includes ozone, and many of the gasses that lead to ozone production, including carbon monoxide, nitrogen oxides (NO, NO2), and hydrocarbons. Measurements of black carbon, an aerosol with important climate impacts and an indicator of combustion processes, were also collected. All of the measurements were obtained from a station atop Pico Mountain, which is part of the Azores Island chain in the Central North Atlantic. The location of the measurements is significant because they were made at an altitude of 2.2 kilometers (km) above sea level, an altitude that can otherwise only be sampled by aircraft in this region of the Atlantic. Thus, these measurements contribute to a unique and long-term set of chemical measurements of aged polluted air masses. The measurement data has been used in a number of analyses that improve our understanding of the role of forest fire emissions versus anthropogenic emissions on the chemistry of the atmosphere and have improved a number of modeling techniques, which ultimately improves our ability to predict the broad impacts of air pollution. These analyses and improvements can be characterized as follows: Performance evaluations of the global model GEOS-Chem, which is used to predict the transport and formation of ozone and other reactive atmospheric chemicals, and attempts to explain the bias observed in the model concentrations when compared to the measurements collected at the station, The development of a new modeling method that improves the tracking of pollution plumes as they are transported from their source to downwind receptors, The use of the measurements to validate and apply a modeling method to estimate the degree of chemical decomposition versus the amount of mixing and dilution of polluted air masses with respect to the concentrations of hydrocarbons, A determination of the role of seasonal cycles of emission, transport, and chemical reaction of observed hydrocarbon concentrations, A determination of the importance and impact of seasonal changes in forest fire characteristics on the concentrations of nitrogen oxides in the Central North Atlantic region, and The determination of an overall decrease in the concentrations of ozone and carbon monoxide in the Central North Atlantic over the past decade due primarily to the reduction of emissions from North America. More information about the on-going measurements made at the station and the results of the analyses can be found at the new project website: https://sites.google.com/a/mtu.edu/pico-wiki/

Agency
National Science Foundation (NSF)
Institute
Division of Atmospheric and Geospace Sciences (AGS)
Application #
0720955
Program Officer
Sylvia A. Edgerton
Project Start
Project End
Budget Start
2007-08-01
Budget End
2012-07-31
Support Year
Fiscal Year
2007
Total Cost
$519,792
Indirect Cost
Name
Michigan Technological University
Department
Type
DUNS #
City
Houghton
State
MI
Country
United States
Zip Code
49931