Upscaling of Peatland-Atmosphere Fluxes of Methane: Small-Scale Heterogeneity in Process Rates and the Pitfalls of "Bucket-and-Slab" Models
Upscaling of Peatland-Atmosphere Fluxes of Methane: Small-Scale Heterogeneity in Process Rates and the Pitfalls of "Bucket-and-Slab" Models
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DOI：
10.1029/2008gm000826
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发表时间：
2009-01-01
期刊：
影响因子：
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通讯作者：
Morris, P. J.
中科院分区：
文献类型：
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作者：
Baird, A. J.;Belyea, L. R.;Morris, P. J.
北方泥炭地碳平衡过程的大多数模型都是在小泥炭地特征尺度上开发的，如丘和凹地，其线性范围可能为10（0）-10（1）m，或在单个泥炭地尺度上（高达10（4）m）。然而，许多方法已应用于与全球环流模型相关联的陆面方案中更大尺度的单元（通常为1度纬度x1度经度或更大）。在这些较大的表示，与规模的模型最初开发，他们考虑到一些垂直变化通过泥炭剖面，但忽略了植被和泥炭性能的水平变化。也就是说，它们包含单一的植被类型，水平均匀的泥炭板，并预测单一的地下水位位置：它们将泥炭地表示为“桶和板”。“在本章中，我们将研究假设空间可变泥炭地的碳平衡过程可以表示为桶和板的准确性。我们关注泥炭地的甲烷（CH 4）通量，并使用标度理论，建议在估计整个泥炭地行为时需要考虑小尺度模式（10（1）-10（2）m）。换句话说，我们建议，桶和板的方法可能不适合放大泥炭地碳循环过程。我们提出了一种替代的，但未经测试的方法，以及跨尺度的相互作用如何影响泥炭地功能的未来工作的议程。
Most models of carbon balance processes in northern peatlands were developed to apply at the scale of small peatland features such as hummocks and hollows, which may have linear extents of 10(0)-10(1) m, or at the scale of individual peatlands (up to 10(4) m). However, many have been applied at the much larger scale of cells in land surface schemes (typically, 1 degrees latitude x 1 degrees longitude or larger), which are linked to global circulation models. In these larger representations, as with the scale for which the models were originally developed, they take some account of vertical variability through the peat profile but ignore horizontal variability in vegetation and peat properties. That is, they contain a single vegetation type, a horizontally uniform slab of peat, and predict a single water table position: they represent the peatland as a "bucket and slab." In this chapter, we examine the accuracy of assuming that carbon balance processes in spatially variable peatlands can be represented as a bucket and slab. We focus on methane (CH4) fluxes from peatlands and, using scaling theory, suggest there is a need to consider small-scale patterning (10(1)-10(2) m) when estimating whole-peatland behavior. In other words, we propose that the bucket-and-slab approach may not be suitable for upscaling peatland carbon cycling processes. We present an alternative, but untested, approach as well as an agenda for future work on how interactions across scales affect peatland functioning.