| Autor: |
Zazzeri, Giulia, Graven, Heather, Xu, Xiaomei, Saboya, Eric, Blyth, Liam, Manning, Alistair J., Chawner, Hannah, Wu, Dien, Hammer, Samuel |
| Zdroj: |
Geophysical Research Letters; August 2023, Vol. 50 Issue: 15 |
| Abstrakt: |
Radiocarbon (14C) is a powerful tracer of fossil emissions because fossil fuels are entirely depleted in 14C, but observations of 14CO2and especially 14CH4in urban regions are sparse. We present the first observations of 14C in both methane (CH4) and carbon dioxide (CO2) in an urban area (London) using a recently developed sampling system. We find that the fossil fraction of CH4and the atmospheric concentration of fossil CO2are consistently higher than simulated values using the atmospheric dispersion model NAME coupled with emission inventories. Observed net biospheric uptake in June–July is not well correlated with simulations using the SMURF model with NAME. The results show the partitioning of fossil and biospheric CO2and CH4in cities can be evaluated and improved with 14C observations when the nuclear power plants influence is negligible. Radiocarbon (14C) is an ideal tracer of fossil emissions, as fossil fuels have lost all 14C during millions of years of burial underground. When fossil carbon is re‐introduced into the atmosphere, it exerts a strong dilution of the radiocarbon to total carbon ratio. By measuring this ratio in the atmosphere, we can quantify fossil methane and carbon dioxide emissions. This is the first combined study of 14C in both atmospheric methane and carbon dioxide at regional scale. Atmospheric radiocarbon measurements in central London reveal higher fossil CH4and CO2present, compared to simulationsRadiocarbon measurements show biospheric uptake of CO2in July that is stronger than simulationsNuclear power plants interfere with radiocarbon measurements in London when air is coming from Europe Atmospheric radiocarbon measurements in central London reveal higher fossil CH4and CO2present, compared to simulations Radiocarbon measurements show biospheric uptake of CO2in July that is stronger than simulations Nuclear power plants interfere with radiocarbon measurements in London when air is coming from Europe |
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