| Autor: |
Pathakoti, Mahesh, Kanchana, A. L., Mahalakshmi, D. V., Guha, Tania, Raja, P., Nalini, K., Rajan, K. S., Sesha Sai, M. V. R., Dadhwal, V. K. |
| Zdroj: |
Journal of Geophysical Research - Atmospheres; April 2023, Vol. 128 Issue: 8 |
| Abstrakt: |
Diurnal variation of atmospheric CO2and its driving factors are studied using high‐precision in situ mixing ratio measurements and stable carbon isotopic CO2(δ13C‐CO2) for the first time over Shadnagar, a suburban site in India, from November 2018 to October 2019. The annual mean mixing ratios of atmospheric CO2and δ13C‐CO2are observed to be 414.76 ± 4.26 ppm and −11.19 ‰ ± 1.63 ‰. Maximum diurnal variability of atmospheric CO2was observed in summer monsoon (17.30 ± 9.29 ppm), and the minimum was noticed in winter (7.19 ± 0.11 ppm), indicating strong seasonality in diurnal variability of amplitude. To characterize the atmospheric CO2sources, the Miller‐Tans model was implemented separately using the CO2and its δ13C‐CO2isotopic data during day and night. However, a strong source signature of δ13C‐CO2was observed during the night‐time of summer monsoon with a slope of −37.42‰ ± 0.73‰, obtained using a reduced major axis regression. The identified source indicates possible emissions from fossil fuel combustion. Further, a Lagrangian back trajectory analysis was performed to study the influence of transport on the observed CO2mixing ratios. The model trajectory confirms the influence of the Indian summer monsoon on the variations of atmospheric CO2mixing ratios. Our study shows that fossil fuel emissions are one of the major contributors of CO2in the study location (about ∼2 to 4 ppm) with biogenic fluxes adding a clear seasonality ranging from −8 to 4 ppm. At a suburban site in India, the present study looked at the diurnal variation of seasonal atmospheric CO2and its stable isotopes, 13C‐CO2. We used the Miller‐Tans model on seasonal data to capture the driving processes of atmospheric CO2during day and night hours. A high source/sink signature of 13C was identified during the night of the summer monsoon. The presence of C3ecosystem respiration and combustion is attributed as the source. Our research provided clear evidence that, in addition to short‐ and long‐range anthropogenic impacts, changes in the isotopic composition of atmospheric CO2during photosynthesis and biogenic respiration are related to changes in atmospheric CO2concentration. The study focused on the diurnal variability of atmospheric CO2mixing ratio and δ13C‐CO2on a seasonal basisDetermination of δ13C signature of atmospheric CO2sources using Miller‐Tans modelInvestigated the influence of transport on seasonal variability of atmospheric CO2using the Lagrangian transport model and inventory fluxes The study focused on the diurnal variability of atmospheric CO2mixing ratio and δ13C‐CO2on a seasonal basis Determination of δ13C signature of atmospheric CO2sources using Miller‐Tans model Investigated the influence of transport on seasonal variability of atmospheric CO2using the Lagrangian transport model and inventory fluxes |
| Databáze: |
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