Modeling Carbon Accumulation and Permafrost Dynamics of Northern Peatlands Since the Holocene
Modeling Carbon Accumulation and Permafrost Dynamics of Northern Peatlands Since the Holocene
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DOI：
10.1029/2022jg007009
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发表时间：
2022-11
期刊：
影响因子：
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通讯作者：
Bailu Zhao;Q. Zhuang;S. Frolking
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文献类型：
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作者：
Bailu Zhao;Q. Zhuang;S. Frolking
北方泥炭地是一个大的碳库，往往作为一个碳汇，但容易受到气候变暖。为了了解泥炭地在全球碳气候反馈中的作用，有必要准确量化其碳储量变化和分解。在这项研究中，一个基于过程的模型，泥炭地陆地生态系统模型，被用来模拟泛北极泥炭地C动态从15 ka BP到1990年。为了提高模拟的准确性，考虑了空间上明确的水径流过程，使用了四个不同的泛北极泥炭地范围数据集，并使用神经网络方法开发了一个空间上明确的泥炭基数据集。该模型根据2055个泥炭厚度观测值进行校准，并将参数插值到泛北极地区。使用该模型，我们估计，在1990年，泛北极泥炭地土壤碳储量为396-421 Pg C，全新世平均碳积累速率为22.9 g C·m−2 yr−1。我们估计的泥炭永冻土发展历史与基于多代理的古气候数据集和岩心导出的永冻土区域动态基本一致。在人类世气候变暖的影响下，在冻融区和无冻土区，泥炭碳积累速率降低，而在冻土区，泥炭碳积累速率增加。我们的研究表明，如果当前的永久冻土区在变暖的未来切换到无永久冻土条件，整个泛北极地区的泥炭碳积累率将下降，但这些泥炭地的汇和源活动仍然不确定。
Northern peatlands are a large C stock and often act as a C sink, but are susceptible to climate warming. To understand the role of peatlands in the global carbon‐climate feedback, it is necessary to accurately quantify their C stock changes and decomposition. In this study, a process‐based model, the Peatland Terrestrial Ecosystem Model, is used to simulate pan‐Arctic peatland C dynamics from 15 ka BP to 1990. To improve the accuracy of the simulation, spatially explicit water run‐on and run‐off processes were considered, four different pan‐Arctic peatland extent data sets were used, and a spatially explicit peat basal date data set was developed using a neural network approach. The model was calibrated against 2055 peat thickness observations and the parameters were interpolated to the pan‐Arctic region. Using the model, we estimate that, in 1990, the pan‐Arctic peatlands soil C stock was 396–421 Pg C, and the Holocene average C accumulation rate was 22.9 g C·m−2 yr−1. Our estimated peat permafrost development history generally agrees with multi‐proxy‐based paleo‐climate data sets and core‐derived permafrost areal dynamics. Under Anthropocene warming, in the freeze‐thaw and permafrost‐free regions, the peat C accumulation rate decreased, but it increased in permafrost regions. Our study suggests that if current permafrost regions switch to permafrost‐free conditions in a warming future, the peat C accumulation rate of the entire pan‐Arctic region will decrease, but the sink and source activities of these peatlands are still uncertain.