globalchange  > 气候变化与战略
DOI: 10.1073/pnas.2005253117
论文题名:
Large and seasonally varying biospheric CO2 fluxes in the Los Angeles megacity revealed by atmospheric radiocarbon
作者: Miller J.B.; Lehman S.J.; Verhulst K.R.; Miller C.E.; Duren R.M.; Yadav V.; Newman S.; Sloop C.D.
刊名: Proceedings of the National Academy of Sciences of the United States of America
ISSN: 0027-8424
出版年: 2020
卷: 117, 期:43
起始页码: 26681
结束页码: 26687
语种: 英语
英文关键词: Carbon dioxide ; Radiocarbon ; Urban
Scopus关键词: carbon ; carbon dioxide ; fossil fuel ; California ; carbon cycle ; environmental monitoring ; exhaust gas ; human ; procedures ; season ; Carbon Cycle ; Carbon Dioxide ; Carbon Isotopes ; Environmental Monitoring ; Fossil Fuels ; Humans ; Los Angeles ; Seasons ; Vehicle Emissions
英文摘要: Measurements of Δ14C and CO2 can cleanly separate biogenic and fossil contributions to CO2 enhancements above background. Our measurements of these tracers in air around Los Angeles in 2015 reveal high values of fossil CO2 and a significant and seasonally varying contribution of CO2 from the urban biosphere. The biogenic CO2 is composed of sources such as biofuel combustion and human metabolism and an urban biospheric component likely originating from urban vegetation, including turf and trees. The urban biospheric component is a source in winter and a sink in summer, with an estimated amplitude of 4.3 parts per million (ppm), equivalent to 33% of the observed annual mean fossil fuel contribution of 13 ppm. While the timing of the net carbon sink is out of phase with wintertime rainfall and the sink seasonality of Southern California Mediterranean ecosystems (which show maximum uptake in spring), it is in phase with the seasonal cycle of urban water usage, suggesting that irrigated urban vegetation drives the biospheric signal we observe. Although 2015 was very dry, the biospheric seasonality we observe is similar to the 2006–2015 mean derived from an independent Δ14C record in the Los Angeles area, indicating that 2015 biospheric exchange was not highly anomalous. The presence of a large and seasonally varying biospheric signal even in the relatively dry climate of Los Angeles implies that atmospheric estimates of fossil fuel–CO2 emissions in other, potentially wetter, urban areas will be biased in the absence of reliable methods to separate fossil and biogenic CO2 © 2020 National Academy of Sciences. All rights reserved.
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/163979
Appears in Collections:气候变化与战略

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作者单位: Miller, J.B., National Oceanic and Atmospheric Administration Global Monitoring Laboratory, Boulder, CO 80305, United States; Lehman, S.J., Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO 80309, United States; Verhulst, K.R., Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, United States; Miller, C.E., Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, United States; Duren, R.M., Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, United States; Yadav, V., Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, United States; Newman, S., Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, United States; Sloop, C.D., Earth Networks, Germantown, MD 20876, United States

Recommended Citation:
Miller J.B.,Lehman S.J.,Verhulst K.R.,et al. Large and seasonally varying biospheric CO2 fluxes in the Los Angeles megacity revealed by atmospheric radiocarbon[J]. Proceedings of the National Academy of Sciences of the United States of America,2020-01-01,117(43)
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