干旱区生态环境知识资源中心(Arid): Apparent ecosystem carbon turnover time: uncertainties and robust features

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DOI	10.5194/essd-12-2517-2020
	Apparent ecosystem carbon turnover time: uncertainties and robust features
	Fan, Naixin; Koirala, Sujan; Reichstein, Markus; Thurner, Martin; Avitabile, Valerio; Santoro, Maurizio; Ahrens, Bernhard; Weber, Ulrich; Carvalhais, Nuno
通讯作者	Fan, NX ; Carvalhais, N
来源期刊	EARTH SYSTEM SCIENCE DATA
ISSN	1866-3508
EISSN	1866-3516
出版年	2020
卷号	12 期号:4 页码:2517-2536
英文摘要	The turnover time of terrestrial ecosystem carbon is an emergent ecosystem property that quantifies the strength of land surface on the global carbon cycle-climate feedback. However, observation- and modeling-based estimates of carbon turnover and its response to climate are still characterized by large uncertainties. In this study, by assessing the apparent whole ecosystem carbon turnover times (tau) as the ratio between carbon stocks and fluxes, we provide an update of this ecosystem level diagnostic and its associated uncertainties in high spatial resolution (0.083 degrees) using multiple, state-of-the-art, observation-based datasets of soil organic carbon stock (C-soil), vegetation biomass (C-veg) and gross primary productivity (GPP). Using this new ensemble of data, we estimated the global median tau to be 43(-7)(+7) yr (median(-difference to percentile 25)(+difference to percentile 75)) when the full soil is considered, in contrast to limiting it to 1 m depth. Only considering the top 1 m of soil carbon in circumpolar regions (assuming maximum active layer depth is up to 1 m) yields a global median tau of 37(-6)(+3) yr, which is longer than the previous estimates of 23(-4)(+7) yr (Carvalhais et al., 2014). We show that the difference is mostly attributed to changes in global C-soil estimates. C-soil accounts for approximately 84 % of the total uncertainty in global tau estimates; GPP also contributes significantly (15 %), whereas C veg contributes only marginally (less than 1 %) to the total uncertainty. The high uncertainty in C-soil is reflected in the large range across state-of-the-art data products, in which full-depth C-soil spans between 3362 and 4792 PgC. The uncertainty is especially high in circumpolar regions with an uncertainty of 50 % and a low spatial correlation between the different datasets (0.2 < r < 0.5) when compared to other regions (0.6 < r < 0.8). These uncertainties cast a shadow on current global estimates of tau in circumpolar regions, for which further geographical representativeness and clarification on variations in C-soil with soil depth are needed. Different GPP estimates contribute significantly to the uncertainties of tau mainly in semiarid and arid regions, whereas C-veg causes the uncertainties of tau in the subtropics and tropics. In spite of the large uncertainties, our findings reveal that the latitudinal gradients of tau are consistent across different datasets and soil depths. The current results show a strong ensemble agreement on the negative correlation between tau and temperature along latitude that is stronger in temperate zones (30-60 degrees; N) than in the subtropical and tropical zones (30 degrees S-30 degrees N). Additionally, while the strength of the tau-precipitation correlation was dependent on the C-soil data source, the latitudinal gradients also agree among different ensemble members. Overall, and despite the large variation in tau, we identified robust features in the spatial patterns of tau that emerge beyond the differences stemming from the data-driven estimates of C-soil, C-veg and GPP. These robust patterns, and associated uncertainties, can be used to infer tau-climate relationships and for constraining contemporaneous behavior of Earth system models (ESMs), which could contribute to uncertainty reductions in future projections of the carbon cycle-climate feedback. The dataset of tau is openly available at https://doi.org/10.17871/bgitau.201911 (Fan et al., 2019).
类型	Article ; Data Paper
语种	英语
开放获取类型	Green Submitted, gold
收录类别	SCI-E
WOS记录号	WOS:000582385600001
WOS关键词	EARTH SYSTEM MODELS ; SOIL ORGANIC-CARBON ; TEMPERATURE SENSITIVITY ; CLIMATE ; VEGETATION ; DIOXIDE ; BOREAL ; STOCK ; FEEDBACKS ; DENSITY
WOS类目	Geosciences, Multidisciplinary ; Meteorology & Atmospheric Sciences
WOS研究方向	Geology ; Meteorology & Atmospheric Sciences
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/327120
作者单位	[Fan, Naixin; Koirala, Sujan; Reichstein, Markus; Ahrens, Bernhard; Weber, Ulrich; Carvalhais, Nuno] Max Planck Inst Biogeochem, Hans Knoll Str 10, D-07745 Jena, Germany; [Thurner, Martin] Senckenberg Gesell Naturforsch, Biodivers & Climate Res Ctr BiK, Senckenberganlage 25, D-60325 Frankfurt, Germany; [Avitabile, Valerio] Joint Res Ctr, European Commiss, Via E Fermi 2749, I-21027 Ispra, Italy; [Santoro, Maurizio] Gamma Remote Sensing, CH-3073 Gumlingen, Switzerland; [Carvalhais, Nuno] Univ Nova Lisboa, Fac Ciencias & Tecnol, Dept Ciencias & Engn Ambiente, DCEA,FCT, P-2829516 Caparica, Portugal
推荐引用方式 GB/T 7714	Fan, Naixin,Koirala, Sujan,Reichstein, Markus,et al. Apparent ecosystem carbon turnover time: uncertainties and robust features[J],2020,12(4):2517-2536.
APA	Fan, Naixin.,Koirala, Sujan.,Reichstein, Markus.,Thurner, Martin.,Avitabile, Valerio.,...&Carvalhais, Nuno.(2020).Apparent ecosystem carbon turnover time: uncertainties and robust features.EARTH SYSTEM SCIENCE DATA,12(4),2517-2536.
MLA	Fan, Naixin,et al."Apparent ecosystem carbon turnover time: uncertainties and robust features".EARTH SYSTEM SCIENCE DATA 12.4(2020):2517-2536.