Anthropogenic and Biogenic Features of Long-Term Measured CO2 Flux in North Downtown Houston, Texas
| Autor: | Gunnar W. Schade, Changhyoun Park |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Environmental Engineering
010504 meteorology & atmospheric sciences Meteorology Eddy covariance Vegetation 010501 environmental sciences Management Monitoring Policy and Law Seasonality Atmospheric sciences medicine.disease 01 natural sciences Pollution Carbon cycle chemistry.chemical_compound chemistry Photosynthetically active radiation Carbon dioxide medicine Environmental science Ecosystem Ecosystem respiration Waste Management and Disposal 0105 earth and related environmental sciences Water Science and Technology |
| Zdroj: | Journal of Environmental Quality. 45:253-265 |
| ISSN: | 0047-2425 |
| Popis: | Long-term urban carbon cycle studies remain rare despite the importance of carbon for energy, air quality, and climate change. To study spatial and temporal variations of energy and carbon fluxes in a subtropical urban environment, eddy covariance flux measurements were conducted north of downtown Houston, TX, using a tall radio-tower installation. The results of the first 2 yr of measurements show that both concentrations and fluxes of CO display typical seasonal and diurnal variations in urban areas. The seasonal variation of net CO flux is driven by steady anthropogenic emissions dominated by car traffic and human respiration, moderated by the local deciduous tree foliage. Weekday-weekend differences were observed in carbon fluxes, but not concentrations, while diurnal changes were dominated by rush-hour peaks from traffic and vegetation influences. Interestingly, CO and CO concentrations, but not CO flux, exhibited long-term declines, especially comparing pre- and post-Hurricane Ike periods. A directional analysis of CO fluxes revealed that the highest fluxes typically occurred from northwest directions, most likely due to emissions from small industrial sources. Car traffic as carbon source was revealed via correlations of CO with CO during the morning rush hours, and of CO flux with traffic counts during winter time. The influence of urban vegetation on net CO fluxes was identified via correlations with daytime photosynthetically active radiation due to photosynthesis, and with nighttime temperatures due to ecosystem respiration. The study site is a net source of CO throughout all seasons. |
| Databáze: | OpenAIRE |
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