A simple model of stream nitrate concentrations in forested and deforested catchments in Mid-Wales
A simple model of stream nitrate concentrations in forested and deforested catchments in Mid-Wales
复制标题
威尔士中部森林和森林砍伐流域溪流硝酸盐浓度的简单模型
DOI：
10.1016/0022-1694(94)90046-9
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
A. Eatherall
中科院分区：
文献类型：
--
作者：
W. Sloan;A. Jenkins;A. Eatherall
一个模型是专门为模拟流中的硝酸盐浓度在大约每周的时间间隔在高地森林和高沼地集水区。它是建立在所观察到的硝酸盐浓度的基础上，在雨水和两个流，Hafren和霍尔，Plynlimon，中威尔士，长期的数据记录存在。Hore流域最近经历了大规模的砍伐森林，一个简单的回归模型，温度流硝酸盐浓度能够模拟硝酸盐浓度的季节性波动观察到的Hafren。然而，这忽略了硝酸盐通过湿沉降的流入，并且无法模拟土地利用变化。回归模型发展成一个简单的动态模型，其中包括一个沉积项和生物量指标。扩展卡尔曼滤波算法被用来估计参数的最佳值，并评估模型的结构。该模型被应用到这两个集水区，观测和模拟硝酸盐浓度之间的拟合在Hafren是好的。在霍尔，该模型能够捕捉到硝酸盐浓度的主要变化，通过森林砍伐和重新种植阶段，虽然详细的短期动态没有得到很好的代表。最后，该模型是相关的，推测，已知发生在大多数集水区的过程。这个简单的模型的目的是作为一个类似的，但更全面的流域模型流氮动力学的发展的一步。
A model is developed specifically for simulating the nitrate concentrations in a stream at approximately weekly intervals in an upland forested and a moorland catchment. It is constructed on the basis of observed nitrate concentrations in rain water and in two streams, the Hafren and the Hore, at Plynlimon, Mid-Wales, where long data records exist. The Hore catchment has recently undergone extensive deforestation.A simple regression model relating temperature to stream nitrate concentrations was capable of simulating the seasonal fluctuations in nitrate concentration observed in the Hafren. However, this ignores the influx of nitrate through wet deposition and is incapable of simulating land-use change. The regression model was developed into a simple dynamic model which includes a deposition term and a biomass indicator. The extended Kalman filter algorithm was used to estimate the optimum values of the parameters and to assess the model structure. The model was applied to both catchments, and the fit between observed and simulated nitrate concentrations at the Hafren was good. At the Hore, the model was able to capture the major changes in nitrate concentration through the deforestation and replanting phases although detailed short-term dynamics were not well represented. Finally, the model is related, speculatively, to processes which are known to occur in most catchments. This simple model is intended as a step towards the development of similar but more comprehensive catchment models of stream nitrogen dynamics.