Optimal design of surface CO2 observation network to constrain China's land carbon sink

Yilong Wang; Xiangjun Tian; Minzheng Duan; Dan Zhu; Dan Liu; Hongqin Zhang; Minqiang Zhou; Min Zhao; Zhe Jin; Jinzhi Ding; Tao Wang; Shilong Piao

doi:10.1016/j.scib.2023.07.010

Optimal design of surface CO₂ observation network to constrain China's land carbon sink

Sci Bull (Beijing). 2023 Aug 15;68(15):1678-1686. doi: 10.1016/j.scib.2023.07.010. Epub 2023 Jul 11.

Authors

Yilong Wang¹, Xiangjun Tian², Minzheng Duan³, Dan Zhu⁴, Dan Liu¹, Hongqin Zhang³, Minqiang Zhou³, Min Zhao¹, Zhe Jin⁴, Jinzhi Ding¹, Tao Wang¹, Shilong Piao⁵

Affiliations

¹ State Key Laboratory of Tibetan Plateau Earth System, Environment and Resources, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China.
² State Key Laboratory of Tibetan Plateau Earth System, Environment and Resources, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy Sciences, Beijing 100049, China. Electronic address: tianxj@itpcas.ac.cn.
³ Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China.
⁴ Institute of Carbon Neutrality, Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.
⁵ State Key Laboratory of Tibetan Plateau Earth System, Environment and Resources, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China; Institute of Carbon Neutrality, Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China. Electronic address: slpiao@pku.edu.cn.

PMID: 37474444
DOI: 10.1016/j.scib.2023.07.010

Abstract

Accurate estimate of the size of land carbon sink is essential for guiding climate mitigation actions to fulfill China's net-zero ambitions before 2060. The atmospheric inversion is an effective approach to provide spatially explicit estimate of surface CO₂ fluxes that are optimally consistent with atmospheric CO₂ measurements. But atmospheric inversion of China's land carbon sink has enormous uncertainties, with one major source arising from the poor coverage of CO₂ observation stations. Here we use a regional atmospheric inversion framework to design an observation network that could minimize uncertainties in inverted estimate of China's land carbon sink. Compared with the large spread of inverted sink (∼1PgCa^-1) from state-of-the-art inversions using existing CO₂ observations, the uncertainty is constrained within 0.3PgCa^-1 when a total of 30 stations were deployed, and is further reduced to approximately 0.2PgCa^-1 when 60 stations were deployed. The proposed stations are mostly distributed over areas with high biosphere productivity during the growing season, such as Southeast China, Northeast China, North China, and the Tibetan Plateau. Moreover, the proposed stations can cover areas where existing satellites have limited coverage due to cloud shadowing in the monsoon season or over complex topography. Such ground-based observation network will be a critical component in the future integrated observing system for monitoring China's land carbon fluxes.

Keywords: Atmospheric inversion; CO(2) stations; China’s land carbon sink; Network design; Posterior uncertainty.