Constraint of satellite CO_(2)retrieval on the global carbon cycle from a Chinese atmospheric inversion system  

作　　者：Zhe JIN Tao WANG Hongqin ZHANG Yilong WANG Jinzhi DING Xiangjun TIAN 

机构地区：[1]State Key Laboratory of Tibetan Plateau Earth System and Resource Environment,Institute of Tibetan Plateau Research,Chinese Academy of Sciences,Beijing 100101,China [2]International Center for Climate and Environment Sciences,Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 100029,China [3]University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Science China Earth Sciences》2023年第3期609-618,共10页中国科学（地球科学英文版）

基　　金：supported by the Second Tibetan Plateau Scientific Expedition and Research Program(2022QZKK0101);the National Natural Science Foundation of China(Grant Nos.41975140&42105150)。

摘　　要：Satellite carbon dioxide(CO_(2))retrievals provide important constraints on surface carbon fluxes in regions that are undersampled by global in situ networks.In this study,we developed an atmospheric inversion system to infer CO_(2)sources and sinks from Orbiting Carbon Observatory-2(OCO-2)column CO_(2)retrievals during 2015–2019,and compared our estimates to five other state-of-the-art inversions.By assimilating satellite CO_(2)retrievals in the inversion,the global net terrestrial carbon sink(net biome productivity,NBP)was found to be 1.03±0.39 petagrams of carbon per year(Pg C yr^(-1));this estimate is lower than the sink estimate of 1.46–2.52 Pg C yr^(-1),obtained using surface-based inversions.We estimated a weak northern uptake of 1.30 Pg C yr-1and weak tropical release of-0.26 Pg C yr^(-1),consistent with previous reports.By contrast,the other inversions showed a strong northern uptake(1.44–2.78 Pg C yr-1),but diverging tropical carbon fluxes,from a sink of 0.77 Pg C yr^(-1) to a source of-1.26 Pg C yr^(-1).During the 2015–2016 El Ni?o event,the tropical land biosphere was mainly responsible for a higher global CO_(2)growth rate.Anomalously high carbon uptake in the northern extratropics,consistent with concurrent extreme Northern Hemisphere greening,partially offset the tropical carbon losses.This anomalously high carbon uptake was not always found in surface-based inversions,resulting in a larger global carbon release in the other inversions.Thus,our satellite constraint refines the current understanding of flux partitioning between northern and tropical terrestrial regions,and suggests that the northern extratropics acted as anomalous high CO_(2)sinks in response to the 2015–2016 El Nino event.

关 键 词：Carbon cycle Atmospheric inversion Net biome productivity(NBP) El Nino 

分 类 号：X16[环境科学与工程—环境科学] X171.1