TY - JOUR
T1 - Source decomposition of eddy-covariance CO2flux measurements for evaluating a high-resolution urban CO2emissions inventory
AU - Wu, Kai
AU - Davis, Kenneth J.
AU - Miles, Natasha L.
AU - Richardson, Scott J.
AU - Lauvaux, Thomas
AU - Sarmiento, Daniel P.
AU - Balashov, Nikolay V.
AU - Keller, Klaus
AU - Turnbull, Jocelyn
AU - Gurney, Kevin R.
AU - Liang, Jianming
AU - Roest, Geoffrey
N1 - Funding Information:
The authors thank Bernd J Haupt (PSU) for data acquisition and quality control. This work was funded by the National Institute of Standards and Technology (Project 70NANB10H245). T Lauvaux was supported by the French research program Make Our Planet Great Again (Project CIUDAD). K R Gurney, J Liang, and G Roest received support from the National Aeronautics and Space Administration (Grant NNX14AJ20G) and the National Institute of Standards and Technology (Grant 70NANB16H264N).
Publisher Copyright:
© 2022 The Author(s). Published by IOP Publishing Ltd.
PY - 2022/7/1
Y1 - 2022/7/1
N2 - We present the comparison of source-partitioned CO2 flux measurements with a high-resolution urban CO2 emissions inventory (Hestia). Tower-based measurements of CO and 14C are used to partition net CO2 flux measurements into fossil and biogenic components. A flux footprint model is used to quantify spatial variation in flux measurements. We compare the daily cycle and spatial structure of Hestia and eddy-covariance derived fossil fuel CO2 emissions on a seasonal basis. Hestia inventory emissions exceed the eddy-covariance measured emissions by 0.36 μmol m-2 s-1 (3.2%) in the cold season and 0.62 μmol m-2 s-1 (9.1%) in the warm season. The daily cycle of fluxes in both products matches closely, with correlations in the hourly mean fluxes of 0.86 (cold season) and 0.93 (warm season). The spatially averaged fluxes also agree in each season and a persistent spatial pattern in the differences during both seasons that may suggest a bias related to residential heating emissions. In addition, in the cold season, the magnitudes of average daytime biological uptake and nighttime respiration at this flux site are approximately 15% and 27% of the mean fossil fuel CO2 emissions over the same time period, contradicting common assumptions of no significant biological CO2 exchange in northern cities during winter. This work demonstrates the effectiveness of using trace gas ratios to adapt eddy-covariance flux measurements in urban environments for disaggregating anthropogenic CO2 emissions and urban ecosystem fluxes at high spatial and temporal resolution.
AB - We present the comparison of source-partitioned CO2 flux measurements with a high-resolution urban CO2 emissions inventory (Hestia). Tower-based measurements of CO and 14C are used to partition net CO2 flux measurements into fossil and biogenic components. A flux footprint model is used to quantify spatial variation in flux measurements. We compare the daily cycle and spatial structure of Hestia and eddy-covariance derived fossil fuel CO2 emissions on a seasonal basis. Hestia inventory emissions exceed the eddy-covariance measured emissions by 0.36 μmol m-2 s-1 (3.2%) in the cold season and 0.62 μmol m-2 s-1 (9.1%) in the warm season. The daily cycle of fluxes in both products matches closely, with correlations in the hourly mean fluxes of 0.86 (cold season) and 0.93 (warm season). The spatially averaged fluxes also agree in each season and a persistent spatial pattern in the differences during both seasons that may suggest a bias related to residential heating emissions. In addition, in the cold season, the magnitudes of average daytime biological uptake and nighttime respiration at this flux site are approximately 15% and 27% of the mean fossil fuel CO2 emissions over the same time period, contradicting common assumptions of no significant biological CO2 exchange in northern cities during winter. This work demonstrates the effectiveness of using trace gas ratios to adapt eddy-covariance flux measurements in urban environments for disaggregating anthropogenic CO2 emissions and urban ecosystem fluxes at high spatial and temporal resolution.
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U2 - 10.1088/1748-9326/ac7c29
DO - 10.1088/1748-9326/ac7c29
M3 - Article
AN - SCOPUS:85134812690
SN - 1748-9326
VL - 17
JO - Environmental Research Letters
JF - Environmental Research Letters
IS - 7
M1 - 074035
ER -