ABSTRACT

Accurate modelling of peat water contents (θ) is critical for wetland studies. We modified the Campbell and Van Genuchten soil water retention curves (SWRCs) by replacing their empirical parameters with measurable properties. Combining the water table depth (d _WT) into SWRCs, we derived formulae for calculating volumetric θ from d _WT, coded in a simple model to test our hypotheses that d _WT is a reliable predictor of θ for peat of low and high water holding capacity at near-saturation. We compared our simulations with time-domain reflectometry θ measurements at Mer Bleue bog (Ontario, Canada) and the Western Peatland fen (Alberta, Canada). Constraining Campbell SWRC at extreme drying and waterlogging rather than wilting point and field capacity produced superior results. The Van Genuchten SWRC was approximated by hyperbolic and inverse hyperbolic segments. When simplified, its performance reconciles with that of the modified Campbell SWRC. Overall, our formulae performed well with generalized peat parameters.

摘要

泥炭含水量（θ）的准确建模对于湿地研究至关重要。通过用可测量的特性代替它们的经验参数，我们修改了Campbell和Van Genuchten的土壤保水曲线（SWRC）。地下水位深度（组合d _WT）成SWRCs，我们推导公式计算体积θ从d _WT，编码在一个简单的模型来测试我们的假说d _WT是一个可靠的预测θ为低的泥炭和高持水能力在接近饱和。我们将仿真与时域反射率θ进行了比较在Mer Bleue沼泽（加拿大安大略省）和Western Peatland fen（加拿大阿尔伯塔省）进行测量。在极度干燥和涝渍的条件下限制Campbell SWRC，而不是在枯萎点和田间灌溉条件下，可获得更好的效果。Van Genuchten SWRC由双曲和反双曲分段近似。经过简化后，其性能与改进的Campbell SWRC的性能一致。总体而言，我们的公式在使用广义泥炭参数时表现良好。