HR: 1340h
AN: B53B-1172    [Abstracts]
TI: Assessing the Influence of Fossil Fuel Emissions on CO₂ Flux Measurements Above a Suburban Ecosystem Using Continuous Traffic Data
AU: * Hiller, R V
EM: hiller@umn.edu
AF: University of Minnesota, Department of Ecology, Evolution, and Behavior, 100 Ecology Building, 1987 Upper Buford Circle, Saint Paul, MN 55108, United States
AU: Wu, J
AF: University of Minnesota, Department of Forest Resources, 115 Green Hall, 1530 Cleveland Avenue North, Saint Paul, MN 55108, United States
AU: McFadden, J P
AF: University of Minnesota, Department of Ecology, Evolution, and Behavior, 100 Ecology Building, 1987 Upper Buford Circle, Saint Paul, MN 55108, United States
AB: Cities are a major source of CO₂, the most important anthropogenic greenhouse gas. Land use within cities is highly heterogeneous and a significant area can be occupied by vegetated surfaces where CO₂ is taken up by photosynthesis and released by ecosystem respiration. Recent remote sensing and modeling studies have estimated that turfgrass lawns cover a surface area of perhaps 163,800~km² in the continental United States with significant CO₂ exchange (Milesi et al. 2005). However, direct measurements of land-atmosphere fluxes above lawn ecosystems have been difficult due to the typically small dimensions of lawns and the heterogeneity of land uses that surround them in an urbanized landscape. We made 2~years of continuous CO₂ exchange measurements using a mobile eddy covariance tower over a <1~ha lawn, which was within the footprint of the KUOM 170-m tall flux tower in a suburban residential neighborhood of Minneapolis-St. Paul, Minnesota. A satellite-derived land-cover map was analyzed to assess the characteristic patch dimensions of lawns in the region in comparison to the selected mobile tower site. An important consequence of urban landscape heterogeneity is that CO₂ fluxes measured above vegetated patches may be influenced by fossil fuel CO₂ sources nearby. In this poster, we use high time resolution, continuously monitored traffic data from the roads surrounding the flux site to quantify the influence of fossil fuel emissions on the net ecosystem CO₂ exchange measurements. Using a flux source area model, we assess the relative influence of fossil fuel emissions in relation to variations of wind field, atmospheric stability, and temporal patterns of traffic volume. The results will be useful for validating emissions models and for scaling up the CO₂ flux from vegetation in developed land. This study is a contribution to the Mid-Continent Intensive Field Campaign of the North American Carbon Program (NACP).
DE: 0426 Biosphere/atmosphere interactions (0315)
DE: 0428 Carbon cycling (4806)
DE: 0478 Pollution: urban, regional and global (0345, 4251)
DE: 0480 Remote sensing
DE: 0493 Urban systems
SC: Biogeosciences [B]
MN: 2007 Fall Meeting