Mathematical models of long-term peatland development have been produced to analyse peatland behaviour. However, existing models ignore the mechanical processes that have the potential to provide important feedback. Here, we propose a one-dimensional model, MPeat, that couples mechanical, ecological and hydrological processes via poroelasticity theory, which couples fluid flow and solid deformation. Poroelasticity formulation in the MPeat is divided into two categories, fully saturated and unsaturated. To validate this formulation, we compare numerical solutions of the fully saturated case with analytical solutions of Terzaghi's problem. Two groups of MPeat simulations are run over 6,000 years using constant and variable climate, and the results are compared to those of two other peat growth models, DigiBog and the Holocene Peat Model. Under both climatic conditions, MPeat generates the expected changes in bulk density, active porosity and hydraulic conductivity at the transition from the unsaturated to the saturated zone. The range of values of peat physical properties simulated by MPeat shows good agreement with field measurement, indicating plausible outputs of the proposed model. Compared to the other peat growth models, the results generated by MPeat illustrate the importance of poroelasticity to the behaviour of peatland. In particular, the inclusion of poroelasticity produces shallower water table depth, accumulates greater quantities of carbon and buffers the effect of climate changes on water table depth and carbon accumulation rates. These results illustrate the importance of mechanical feedbacks on peatland ecohydrology and carbon stock resilience.

中文翻译：

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MPeat——泥炭地开发的完全耦合的机械-生态水文模型

长期泥炭地开发的数学模型已被用于分析泥炭地行为。然而，现有模型忽略了有可能提供重要反馈的机械过程。在这里，我们提出了一个一维模型 MPeat，它通过耦合流体流动和固体变形的孔隙弹性理论将机械、生态和水文过程耦合起来。MPeat 中的孔隙弹性公式分为完全饱和和不饱和两类。为了验证这个公式，我们将完全饱和情况的数值解与 Terzaghi 问题的解析解进行比较。两组 MPeat 模拟使用恒定和可变气候运行了 6000 多年，并将结果与​​其他两个泥炭生长模型 DigiBog 和全新世泥炭模型的结果进行了比较。在这两种气候条件下，MPeat 在从非饱和区到饱和区的过渡中产生预期的体积密度、活性孔隙度和水力传导率变化。MPeat 模拟的泥炭物理特性值范围与现场测量结果非常吻合，表明所提出模型的合理输出。与其他泥炭生长模型相比，MPeat 生成的结果说明了孔隙弹性对泥炭地行为的重要性。特别是，包含孔隙弹性会产生更浅的地下水位深度，积累更多的碳，并缓冲气候变化对地下水位深度和碳积累率的影响。这些结果说明了机械反馈对泥炭地生态水文和碳储量恢复力的重要性。