2009 BES Annual Meeting Presentation and Poster Abstracts
Carbon, water, and heat fluxes in relation to footprints of an eddy-covariance tower in a heterogeneous suburban landscape near Baltimore, Maryland
Co-Authors: Nicanor Saliendra*1, John Hom2, Richard Pouyat2, Gordon Heisler2, David Nowak2, Matthew Patterson2, Ian Yesilonis2, Ben Crawford3, and Sue Grimmond4 1Univ. of MD Baltimore County (UMBC), Center for Urban Environmental Research & Education (CUERE)
Abstract: Micrometeorological methods, such as eddy-covariance, are ideally deployed in homogeneous environments, where footprints (i.e., sources of and sinks for scalars) are fairly uniform around the tower. Thus, measurements of eddy-fluxes in a suburban landscape may create technical difficulties as sinks and sources of carbon dioxide (CO2), water vapor, and heat around the tower’s footprint are non-uniform. We hypothesized that the land cover in conjunction with the prevailing wind direction will significantly influence the variations in eddy-fluxes during the four seasons in a year. A recent land use/land cover map indicated that the impervious surfaces ranged from 5 to 26 % among 8 wind directions (or wedges) within the 1-km radius of the Cub Hill tower. We measured CO2 and energy (i.e., latent and sensible) fluxes using a closed-path eddy-covariance system mounted on top of the 40-m tower. Half-hourly fluxes of CO2 and energy were stratified according to 8 bins (45-degree) of wind direction in each of the 16-day compositing periods for MODIS (250-m resolution) Normalized Difference Vegetation Index (NDVI) during 3 years of study (2004 to 2006). We developed empirical models to establish the relationship between eddy-fluxes, NDVI, and land cover.