A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Validation of modeled carbon-dioxide emissions from an urban neighborhood with direct eddy-covariance measurements
Abstract Modeled carbon-dioxide (CO2) emissions from an urban area are validated against direct eddy-covariance flux measurements. Detailed maps of modeled local carbon-dioxide emissions for a 4 km2 residential neighborhood in Vancouver, BC, Canada are produced. Inputs to the emission model include urban object classifications (buildings, trees, land-cover) automatically derived from Light Detection and Ranging (LiDAR) and optical remote sensing in combination with census, assessment, traffic and measured radiation and climate data. Different sub-models for buildings, transportation, human respiration, soils and vegetation were aggregated. Annual and monthly CO2 emissions were modeled on a spatial grid of 50 m for the entire study area. The study area overlaps with the source area of a micrometeorological flux tower for which continuous CO2 flux data (net exchange) were available for a two-year period. The measured annual total was 6.71 kg C m−2 yr−1with significant seasonal differences (16.0 g C m−2 day−1 in Aug vs. 22.1 g C m−2 day−1 in Dec correlated with the demand for space heating) and weekday-weekend differences (25% lower emissions on weekends attributed to traffic volume differences). Model results were weighted using the long-term turbulent source areas of the tower. Annual total modeled (7.42 kg C m−2 yr−1) and measured emissions agreed within 11%, but show more substantial differences in wind sectors dominated by traffic emissions. Over the year, agreement was better in summer (5% overestimation by model) vs. winter (15% overestimation), which is partially attributed to climate differences unaccounted for in the building energy models. The study shows that direct CO2 flux measurements based on the EC approach - if sites are carefully chosen - are a promising method to validate fine-scale emission inventories/models at the block or neighborhood scale and can inform further model improvements.
Highlights ► Detailed maps of local carbon-dioxide emissions were modeled for a 4 km2 urban area. ► Maps are compared to two full years of direct eddy-covariance (EC) measurements on a tower. ► Modeled annual total carbon emissions agree within 11% with tower measurements. ► Higher differences found in sectors with arterial roads and during heating-period. ► EC measurements are a promising method to validate spatial emission inventories.
Validation of modeled carbon-dioxide emissions from an urban neighborhood with direct eddy-covariance measurements
Abstract Modeled carbon-dioxide (CO2) emissions from an urban area are validated against direct eddy-covariance flux measurements. Detailed maps of modeled local carbon-dioxide emissions for a 4 km2 residential neighborhood in Vancouver, BC, Canada are produced. Inputs to the emission model include urban object classifications (buildings, trees, land-cover) automatically derived from Light Detection and Ranging (LiDAR) and optical remote sensing in combination with census, assessment, traffic and measured radiation and climate data. Different sub-models for buildings, transportation, human respiration, soils and vegetation were aggregated. Annual and monthly CO2 emissions were modeled on a spatial grid of 50 m for the entire study area. The study area overlaps with the source area of a micrometeorological flux tower for which continuous CO2 flux data (net exchange) were available for a two-year period. The measured annual total was 6.71 kg C m−2 yr−1with significant seasonal differences (16.0 g C m−2 day−1 in Aug vs. 22.1 g C m−2 day−1 in Dec correlated with the demand for space heating) and weekday-weekend differences (25% lower emissions on weekends attributed to traffic volume differences). Model results were weighted using the long-term turbulent source areas of the tower. Annual total modeled (7.42 kg C m−2 yr−1) and measured emissions agreed within 11%, but show more substantial differences in wind sectors dominated by traffic emissions. Over the year, agreement was better in summer (5% overestimation by model) vs. winter (15% overestimation), which is partially attributed to climate differences unaccounted for in the building energy models. The study shows that direct CO2 flux measurements based on the EC approach - if sites are carefully chosen - are a promising method to validate fine-scale emission inventories/models at the block or neighborhood scale and can inform further model improvements.
Highlights ► Detailed maps of local carbon-dioxide emissions were modeled for a 4 km2 urban area. ► Maps are compared to two full years of direct eddy-covariance (EC) measurements on a tower. ► Modeled annual total carbon emissions agree within 11% with tower measurements. ► Higher differences found in sectors with arterial roads and during heating-period. ► EC measurements are a promising method to validate spatial emission inventories.
Validation of modeled carbon-dioxide emissions from an urban neighborhood with direct eddy-covariance measurements
Christen, A. (author) / Coops, N.C. (author) / Crawford, B.R. (author) / Kellett, R. (author) / Liss, K.N. (author) / Olchovski, I. (author) / Tooke, T.R. (author) / van der Laan, M. (author) / Voogt, J.A. (author)
Atmospheric Environment ; 45 ; 6057-6069
2011-07-22
13 pages
Article (Journal)
Electronic Resource
English