Abstract:
Urban areas are significant contributors to global CO2 emissions. Observations in Northern Hemisphere cities have provided overviews of the sources, sinks and transport mechanisms of CO2 within these regions. However, similar research within subtropical cities or those found in the Southern Hemisphere have yet to be investigated. Research of such kind pertaining to New Zealand cities such as Auckland is even more limited. A field campaign was conducted during the months of May – September 2012 in Auckland, New Zealand in order to identify patterns of CO2 concentration across the city. As New Zealand’s largest and most populated urban environments, Auckland offered an ideal setup for collecting information regarding CO2 distributions within New Zealand urban environments. The field campaign comprised stationary monitoring at an urban and rural site. Multiple near surface mobile monitoring runs were also conducted along the length of the city in conjunction with the fixed monitoring. The fixed monitoring results showed that CO2 concentrations distinct diurnal cycle. Within the urban region, diurnal concentrations appeared to be largely influenced by traffic emissions during the day and building emissions at night. Within the rural region, concentrations were largely influenced by daytime photosynthesis and night time respiration. These observations were concurrent with the mobile monitoring results which showed more pronounced day time concentrations over urban areas. This ‘dome’ pattern of concentration illustrates the dependence of land use on CO2 concentrations with the rural outskirts being CO2 sinks during the day and the urban area being CO2 sources. The result of this study illustrate the complex relationships between, meteorology, land use and emissions on urban CO2 concentrations.
