Scalar Simulation and Parameterization of Water Table Dynamics in Tropical Peatlands
Scalar Simulation and Parameterization of Water Table Dynamics in Tropical Peatlands
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DOI：
10.1029/2019wr025411
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发表时间：
2019-11-19
影响因子：
5.4
通讯作者：
Harvey, Charles F.
中科院分区：
文献类型：
--
作者：
Cobb, Alexander R.;Harvey, Charles F.
泥炭地覆盖着热带地区的许多低洼地区。热带泥炭地是一个有趣的系统，因为它们在水文和碳储存之间存在紧密的耦合：由于水涝，它们在数千年内积累了碳，并且由于泥炭限制排水，它们在长成圆顶形状后仍然被水淹没。这种内涝和景观形态之间的反馈产生具有特殊水文特性的地貌，使标准流域模型得以简化。在天然的热带泥炭地，地下水位总是接近地表，渗透几乎是立即的。此外，地下水位波动相对于泥炭表面是非常均匀的热带泥炭地，因为这些泥炭地获得形状与统一的地形湿度指数。在本文中，我们表明，由于这些独特的属性，简单的水文模型，表示一个集水区的水力状态的标量，描述总储水量是有用的，在热带泥炭地的物理意义。我们演示了如何有效地获得山坡尺度参数化的transmittance和特定的产量作为地下水位高度的函数的热带泥炭地地下水位，降雨量和地形数据。我们的研究结果表明，天然热带泥炭地子流域可以有效地模拟为单一的水文响应单元的河流流量和洪水预报。
Peatlands cover many low-lying areas in the tropics. Tropical peatlands are intriguing systems because of their tight coupling between hydrology and carbon storage: They accumulate carbon over thousands of years because of waterlogging, and they remain waterlogged after growing into domed shapes because peat restricts drainage. This feedback between waterlogging and landscape morphology generates landforms with special hydrologic properties that enable simplifications of standard watershed models. In natural tropical peatlands, the water table is always near the surface and infiltration is almost immediate. In addition, water table fluctuations relative to the peat surface are remarkably uniform across tropical peatlands because these peatlands acquire shapes with a uniform topographic wetness index. In this paper, we show that because of these distinctive properties, simple hydrologic models that represent the hydraulic state of a catchment by a scalar quantity that describes total water storage are useful and physically meaningful in tropical peatlands. We demonstrate how to efficiently derive hillslope-scale parameterizations of transmissivity and specific yield as functions of water table height for a tropical peatland from water table, rainfall, and topographic data. Our findings suggest that natural tropical peatland subcatchments could be usefully modeled as single hydrologic response units for river flow and flood forecasting.