Linking 13C‐based estimates of land and ocean sinks with predictions of carbon storage from CO2 fertilization of plant growth
Linking 13C‐based estimates of land and ocean sinks with predictions of carbon storage from CO2 fertilization of plant growth
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DOI：
10.3402/tellusb.v51i3.16457
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发表时间：
1999-07
期刊：
影响因子：
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通讯作者：
J. Randerson;M. V. Thompson;C. Field
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文献类型：
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作者：
J. Randerson;M. V. Thompson;C. Field
碳在植物、凋落物和土壤中的停留时间是利用大气δ 13 C测量划分陆地和海洋汇所必需的，也是估算陆地碳储量对大气CO2水平升高引起的净初级生产力（NPP）刺激的响应所必需的。虽然13 C为基础的计算的土地汇下降增加估计陆地碳停留时间（通过化石燃料引起的同位素不平衡项方程描述的全球大气预算的13 CO 2和CO 2），估计土地汇的基础上CO2施肥的植物生长是直接成比例的碳停留时间。在这里，我们使用了一个单一的陆地碳周转模型，Eschergie-Ames-斯坦福大学方法（CASA）地球化学模型，同时估计1984-1990年陆地碳储量使用两种方法。我们的目标是确定部分的13个CO2为基础的土地汇归因于CO2施肥。采用β因子0.46计算了1765 ~ 1990年NPP对大气CO2浓度增加的响应。考虑到基于13 C的碳汇计算中常用的参数，并假设毁林通量为0.8PgC/y，CO2施肥占1984 - 1990年陆地碳汇缺失量的54%。只有当陆地平均滞留时间（MRT）和陆地非平衡强迫大于许多最近的估计值时，CO2施肥才能解释所有缺失的陆地汇。DOI：10.1034/j.1600-0889.1999.t01-2-00007.x
The residence times of carbon in plants, litter, and soils are required for partitioning land and ocean sinks using measurements of atmospheric δ 13 C and also for estimating terrestrial carbon storage in response to net primary production (NPP) stimulation by elevated levels of atmospheric CO 2 . While 13 C-based calculations of the land sink decline with increasing estimates of terrestrial carbon residence times (through the fossil fuel-induced isotopic disequilibrium term in equations describing the global atmospheric budgets of 13 CO 2 and CO 2 ), estimates of land sinks based on CO 2 fertilization of plant growth are directly proportional to carbon residence times. Here we used a single model of terrestrial carbon turnover, the Carnegie–Ames–Stanford Approach (CASA) biogeochemical model, to simultaneously estimate 1984–1990 terrestrial carbon storage using both approaches. Our goal was to identify the fraction of the 13 CO 2 -based land sink attributable to CO 2 fertilization. Uptake from CO 2 fertilization was calculated using a β factor of 0.46 to describe the response of NPP to increasing concentrations of atmospheric CO 2 from 1765 to 1990. Given commonly used parameters in the 13 C-based sink calculation and assuming a deforestation flux of 0.8 Pg C/y, CO 2 fertilization accounts for 54% of the missing terrestrial carbon sink from 1984 to 1990. CO 2 fertilization can account for all of the missing terrestrial sink only when the terrestrial mean residence time (MRT) and the land isodisequilibrium forcing are greater than many recent estimates. DOI: 10.1034/j.1600-0889.1999.t01-2-00007.x