Climate and interannual variability of the atmosphere‐biosphere 13CO2 flux
Climate and interannual variability of the atmosphere‐biosphere 13CO2 flux
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DOI：
10.1029/2002gl015631
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发表时间：
2003-01
影响因子：
5.2
通讯作者：
M. Scholze;J. Kaplan;W. Knorr;M. Heimann
中科院分区：
文献类型：
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作者：
M. Scholze;J. Kaplan;W. Knorr;M. Heimann
我们提出了一种自下而上的方法，利用Lund-Potsam-Jena动态全球植被模型(LPJ-DGVM)模拟陆地碳同位素的变化。LPJ被扩展到包括在同化过程中叶片水平上的13C的同位素分馏，并包括一个完整的陆地碳同位素循环。因此，该模型可以作为气候、大气二氧化碳和二氧化碳同位素比率变化的函数，对生物圈与大气的二氧化碳和13CO2的净交换进行定量分析。LPJ模拟了全球叶水平的平均同位素分馏为17.7‰，年际变化约为0.3‰。大气和陆地生物圈之间13CO2净通量的年际变率约为15pgC‰yr−1。如果叶水平的分馏因子长期保持不变，它将减少到4pgC‰yr−1。考虑到双反卷积研究中气候驱动的变量分馏效应，我们估计这可能意味着推断的陆地和海洋碳汇之间的分配发生0.8pgc yr−1的偏移。
We present a bottom‐up approach to simulate the terrestrial isotopic carbon variations using the Lund‐Potsdam‐Jena dynamic global vegetation model (LPJ‐DGVM). LPJ is extended to include isotopic fractionation of 13C at the leaf level during assimilation and includes a full isotopic terrestrial carbon cycle. The model thus allows a quantitative analysis of the net biosphere exchange of CO2 and 13CO2 with the atmosphere as a function of changes in climate, atmospheric CO2, and the isotope ratio of CO2. LPJ simulates a global mean isotopic fractionation of 17.7‰ at the leaf level with interannual variations of ca. 0.3‰. Interannual variability in the net 13CO2 flux between atmosphere and terrestrial biosphere is of the order of 15 PgC‰ yr−1. It is reduced to 4 PgC‰ yr−1 if the leaf‐level fractionation factor is held constant at the long term mean. Taking climate driven variable fractionation effects into account in double deconvolution studies we estimate that this could imply shifts of up to 0.8 PgC yr−1 in the inferred partitioning between terrestrial and oceanic carbon sinks.