A12A-07
Quantifying atmospheric nitrogen outflow from the Front Range of Colorado
Monday, 14 December 2015: 11:50
3010 (Moscone West)
J A Neuman1, Scott Joseph Eilerman2, Charles A Brock3, Steven S Brown3, William P Dube3, Scott C. Herndon4, John S Holloway1, John B Nowak4, Joseph R Roscioli4, Thomas B Ryerson5, Steven J Sjostedt6, Chelsea R Thompson1, Michael Trainer7, Patrick R Veres3 and Robert J Wild8, (1)CIRES, Boulder, CO, United States, (2)Cooperative Institute for Research in Environmental Sciences, Boulder, CO, United States, (3)NOAA Boulder, Boulder, CO, United States, (4)Aerodyne Research Inc., Billerica, MA, United States, (5)NOAA, Boulder, CO, United States, (6)Georgia Institute of Tech, Atlanta, GA, United States, (7)NOAA Earth System Research Lab, Boulder, CO, United States, (8)Colorado University/NOAA/ESRL, Boulder, CO, United States
Abstract:
Reactive nitrogen emitted to the atmosphere from urban, industrial, and agricultural sources can be transported and deposited far from the source regions, affecting vegetation, soils, and water of sensitive ecosystems. Mitigation of atmospheric nitrogen deposition requires emissions characterization and quantification. Ammonia (NH3), a full suite of gas-phase oxidized nitrogen compounds, and particulate matter were measured from an aircraft that flew downwind from concentrated animal feeding operations, oil and gas extraction facilities, and urban areas along the Colorado Front Range in March and April 2015, as part of the Shale Oil and Natural Gas Nexus (SONGNEX) field study. Additionally, NH3 measurements from a fully instrumented aircraft that flew over the same region in July and August 2014 as part of the Front Range Air Pollution and Photochemistry Experiment (FRAPPE) are used to examine atmospheric nitrogen emission and transport. Cross-wind plume transects and altitude profiles were performed over the source regions and 60-240 km downwind. Plumes were transported in the boundary layer with large NH3 mixing ratios (typically 20-100 ppbv) and were tens of km wide. The NH3 in these plumes provided an atmospheric nitrogen burden greater than 0.2 kg N/ha. Nitrogen oxides and their oxidation products and particulate matter were also enhanced in the plumes, but with concentrations substantially less than NH3. With efficient transport followed by wet deposition, these plumes have the potential to provide a large nitrogen input to the neighboring Rocky Mountain National Park, where nitrogen deposition currently exceeds the ecological critical load of 1.5 kg N/ha/yr.
