气候变化领域集成服务门户(CCPortal): Reconciling the bottom-up and top-down estimates of the methane chemical sink using multiple observations

CCPortal

DOI	10.5194/acp-23-789-2023
	Reconciling the bottom-up and top-down estimates of the methane chemical sink using multiple observations
	Zhao, Yuanhong; Saunois, Marielle; Bousquet, Philippe; Lin, Xin; Hegglin, Michaela I.; Canadell, Josep G.; Jackson, Robert B.; Zheng, Bo
发表日期	2023
ISSN	1680-7316
EISSN	1680-7324
起始页码	789
结束页码	807
卷号	23 期号:1 页码:19
英文摘要	The methane chemical sink estimated by atmospheric chemistry models (bottom-up method) is significantly larger than estimates based on methyl chloroform (MCF) inversions (top-down method). The difference is partly attributable to large uncertainties in hydroxyl radical (OH) concentrations simulated by the atmospheric chemistry models used to derive the bottom-up estimates. In this study, we propose a new approach based on OH precursor observations and a chemical box model. This approach contributes to improving the 3D distributions of tropospheric OH radicals obtained from atmospheric chemistry models and reconciling bottom-up and top-down estimates of the chemical loss of atmospheric methane. By constraining simulated OH precursors with observations, the global mean tropospheric column-averaged air-mass-weighted OH concentration ([OH](trop-M)) is similar to 10x10(5) molec. cm(-3) (which is 2x10(5) molec. cm(-3) lower than the original model-simulated global [OH](trop-M)) and agrees with that obtained by the top-down method based on MCF inversions. With OH constrained by precursor observations, the methane chemical loss is 471-508 Tg yr(-1), averaged from 2000 to 2009. The new adjusted estimate is in the range of the latest top-down estimate of the Global Carbon Project (GCP) (459-516 Tg yr(-1)), contrary to the bottom-up estimates that use the original model-simulated OH fields (577-612 Tg yr(-1)). The overestimation of global [OH](trop-M) and methane chemical loss simulated by the atmospheric chemistry models is caused primarily by the models' underestimation of carbon monoxide and total ozone column, and overestimation of nitrogen dioxide. Our results highlight that constraining the model-simulated OH fields with available OH precursor observations can help improve bottom-up estimates of the global methane sink.
学科领域	Environmental Sciences; Meteorology & Atmospheric Sciences
语种	英语
WOS研究方向	Environmental Sciences & Ecology ; Meteorology & Atmospheric Sciences
WOS记录号	WOS:000917923900001
来源期刊	ATMOSPHERIC CHEMISTRY AND PHYSICS
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/273668
作者单位	Ocean University of China; Ocean University of China; UDICE-French Research Universities; Universite Paris Saclay; CEA; Centre National de la Recherche Scientifique (CNRS); Helmholtz Association; Research Center Julich; University of Reading; Commonwealth Scientific & Industrial Research Organisation (CSIRO); Stanford University; Stanford University; Tsinghua University
推荐引用方式 GB/T 7714	Zhao, Yuanhong,Saunois, Marielle,Bousquet, Philippe,et al. Reconciling the bottom-up and top-down estimates of the methane chemical sink using multiple observations[J],2023,23(1):19.
APA	Zhao, Yuanhong.,Saunois, Marielle.,Bousquet, Philippe.,Lin, Xin.,Hegglin, Michaela I..,...&Zheng, Bo.(2023).Reconciling the bottom-up and top-down estimates of the methane chemical sink using multiple observations.ATMOSPHERIC CHEMISTRY AND PHYSICS,23(1),19.
MLA	Zhao, Yuanhong,et al."Reconciling the bottom-up and top-down estimates of the methane chemical sink using multiple observations".ATMOSPHERIC CHEMISTRY AND PHYSICS 23.1(2023):19.