Reconciliation of top-down and bottom-up CO2 fluxes in Siberian larch forest
Reconciliation of top-down and bottom-up CO2 fluxes in Siberian larch forest
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西伯利亚落叶松森林自上而下和自下而上二氧化碳通量的协调
DOI：
10.1088/1748-9326/aa926d
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发表时间：
2017
影响因子：
6.7
通讯作者：
et al
中科院分区：
文献类型：
--
作者：
Takata Kumiko;Patra Prabir K;Kotani Ayumi;et al
在全球、区域和局地尺度上，不同方法测定的CO2通量差异很大.比较了2004 - 2013年西伯利亚雅库茨克CO2净通量的三种自下而上方法（塔观测（TWR）、地球化学模型（GTM）和数据驱动模型（SVR））和大气逆温集合（自上而下方法，INV）。该地区的特点是在平坦的地形上高度均匀的落叶松林。雅库茨克周围的生态系统通过所有方法都显示出CO2的净汇（2004 - 2007年期间，TWR的平均值为10.9 g C m − 2 month − 1，GTM为4.28 g C m − 2 month − 1，SVR在两个不同尺度上为5.62 g C m − 2 month − 1和0.863 g C m − 2 month − 1，INV为4.89 g C m − 2 month − 1）。在夏季（6月至8月），三种自下而上方法的吸收量（范围为88.1至191.8 g C m − 2月− 1）小于自上而下方法（223.6 g C m − 2月− 1）。因此，季节性周期的峰谷振幅是更大的逆模型比自下而上的方法。在模型间变化范围内，四种方法的月平均季节周期一致。用反演模式集合和一个场地尺度数据驱动模式估计的年际变率（最大-最小范围为35.8 g C m − 2月− 1和34.2 g C m − 2月− 1）与塔观测结果更相似（42.4 g C m − 2 month − 1）高于地球化学模型和大尺度数据驱动模型（9.5 g C m − 2 month − 1和1.45 g C m − 2 month − 1）。逆模型和塔观察发现，由于不寻常的内涝，2008年之后二氧化碳吸收量减少。
Carbon dioxide (CO 2) fluxes by different methods vary largely at global, regional and local scales. The net CO 2 fluxes by three bottom-up methods (tower observation (TWR), biogeochemical models (GTM), and a data-driven model (SVR)), and an ensemble of atmospheric inversions (top-down method, INV) are compared in Yakutsk, Siberia for 2004–2013. The region is characterized by highly homogeneous larch forest on a flat terrain. The ecosystem around Yakutsk shows a net sink of CO 2 by all the methods (means during 2004–2007 were 10.9 g C m− 2 month− 1 by TWR, 4.28 g C m− 2 month− 1 by GTM, 5.62 g C m− 2 month− 1 and 0.863 g C m− 2 month− 1 by SVR at two different scales, and 4.89 g C m− 2 month− 1 by INV). Absorption in summer (June–August) was smaller by three bottom-up methods (ranged from 88.1 to 191.8 g C m− 2 month− 1) than the top-down method (223.6 g C m− 2 month− 1). Thus the peak-to-trough amplitude of the seasonal cycle is greater for the inverse models than bottom-up methods. The monthly-mean seasonal cycles agree among the four methods within the range of inter-model variations. The interannual variability estimated by an ensemble of inverse models and a site-scale data-driven model (the max-min range was 35.8 g C m− 2 month− 1 and 34.2 g C m− 2 month− 1) is more similar to that of the tower observation (42.4 g C m− 2 month− 1) than those by the biogeochemical models and the large-scale data-driven model (9.5 g C m− 2 month− 1 and 1.45 g C m− 2 month− 1). The inverse models and tower observations captured a reduction in CO 2 uptake after 2008 due to unusual waterlogging.