Seasonally varying contributions to urban CO2 in the Chicago, IL, USA region: insights from a high-resolution CO2 concentration and δ13C record

Understanding urban carbon cycling is essential given that cities sustain 54% of the global population and contribute 70% of anthropogenic CO2 emissions. When combined with CO2 concentration measurements ([CO2]), stable carbon isotope analyses (δ13C) can differentiate sources of CO2, including ecosystem respiration and combustion of fossil fuels, such as petroleum and natural gas. In this study, we used a wavelength scanned-cavity ringdown spectrometer to collect ~2x106 paired measurements for [CO2] and δ13C values in Evanston, IL for August 2011 through February 2012. Evanston is located immediately north of Chicago, IL, the third largest city in the United States. The measurements represent one of the longest records of urban [CO2] and δ13C values thus far reported. We also compiled local meteorological information, as well as complementary [CO2] and δ13C data for background sites in Park Falls, WI and Mauna Loa, HI. We use the dataset to examine how ecosystem processes, fossil fuel u...

理解城市碳循环至关重要，因为全球54%的人口居住在城市，且城市贡献了70%的人为二氧化碳排放。将稳定碳同位素分析（δ¹³C）与二氧化碳浓度测量值（[CO₂]）相结合，可区分二氧化碳的来源，包括生态系统呼吸以及石油、天然气等化石燃料的燃烧。本研究中，我们使用波长扫描腔衰荡光谱仪（wavelength scanned-cavity ringdown spectrometer）在2011年8月至2012年2月期间，于伊利诺伊州埃文斯顿（Evanston, IL）收集了约2×10⁶组[CO₂]与δ¹³C的配对测量数据。埃文斯顿紧邻美国第三大城市伊利诺伊州芝加哥市的北部。该测量数据是目前已报道的城市[CO₂]与δ¹³C值的最长时间序列记录之一。我们还汇编了当地气象信息，以及威斯康星州帕克福尔斯（Park Falls, WI）和夏威夷州莫纳罗亚（Mauna Loa, HI）背景站点的补充[CO₂]与δ¹³C数据。我们利用该数据集分析生态系统过程、化石燃料使...