Apparent ecosystem carbon turnover time: Uncertainties and robust features
| Autor: | Nuno Carvalhais, Naixin Fan, Valerio Avitabile, Maurizio Santoro, Bernhard Ahrens, Sujan Koirala, Markus Reichstein, Martin Thurner, Ulrich Weber |
|---|---|
| Přispěvatelé: | DCEA - Departamento de Ciências e Engenharia do Ambiente |
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
010504 meteorology & atmospheric sciences
Earth and Planetary Sciences(all) Subtropics Atmospheric sciences 01 natural sciences Latitude Carbon cycle ddc:570 Temperate climate ddc:550 SDG 13 - Climate Action Stock (geology) lcsh:Environmental sciences 0105 earth and related environmental sciences SDG 15 - Life on Land lcsh:GE1-350 lcsh:QE1-996.5 Tropics 04 agricultural and veterinary sciences Soil carbon lcsh:Geology 040103 agronomy & agriculture Spatial ecology 0401 agriculture forestry and fisheries General Earth and Planetary Sciences Environmental science |
| Zdroj: | Repositório Científico de Acesso Aberto de Portugal Repositório Científico de Acesso Aberto de Portugal (RCAAP) instacron:RCAAP Earth System Science Data, Vol 12, Pp 2517-2536 (2020) Earth System Science Data |
| ISSN: | 1866-3516 |
| Popis: | 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 (τ) 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∘) using multiple, state-of-the-art, observation-based datasets of soil organic carbon stock (Csoil), vegetation biomass (Cveg) and gross primary productivity (GPP). Using this new ensemble of data, we estimated the global median τ 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 τ 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 Csoil estimates. Csoil accounts for approximately 84 % of the total uncertainty in global τ estimates; GPP also contributes significantly (15 %), whereas Cveg contributes only marginally (less than 1 %) to the total uncertainty. The high uncertainty in Csoil is reflected in the large range across state-of-the-art data products, in which full-depth Csoil 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 |
| Databáze: | OpenAIRE |
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