Representativeness of Carbon Dioxide Fluxes Measured by Eddy Covariance over a Mediterranean Urban District with Equipment Setup Restrictions

The CO2 fluxes measured by the eddy covariance technique (EC) are presented for a district of the urban area of Bari (Italy). The applicability of the EC method was satisfied even though the measurements were taken at a limited height. The CO2 fluxes are representative of an area with public offices and schools, the university campus, green areas, and busy roads with intensive traffic during school and office times. The measurements were carried out in March-June, covering late winter, characterized by huge vehicle traffic and domestic heating, until late spring, characterized by reduced activities for schools and the university. The source area was determined as a function of atmospheric stability, for data with the ratio between measurement-height/buildings-height in the range of 1.3-1.5. The measured CO2 fluxes were compared to gas consumption values. The results show that the district is a strong source of CO2 during the winter. Emissions were drastically reduced (-82%) after the heating was switched off, and a further decrease in CO2 emissions (-50%) occurred with the reduction of school activities, partly due to the mitigating effect of green areas with large trees in the area.