A Monte Carlo approach to the inverse problem of diffuse pollution risk in agricultural catchments.
A Monte Carlo approach to the inverse problem of diffuse pollution risk in agricultural catchments.
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DOI：
10.1016/j.scitotenv.2012.06.047
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发表时间：
2012-04
期刊：
影响因子：
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通讯作者：
D. Milledge;S. Lane;A. Heathwaite;S. Reaney
中科院分区：
文献类型：
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作者：
D. Milledge;S. Lane;A. Heathwaite;S. Reaney
在集水区运作的水文和生态地球化学过程通过输送细沉积物、营养物和有机物影响淡水系统的生态质量。大多数试图模拟污染物从陆地扩散到水中的模型都是还原论的。在这些模型中，为确保普遍适用性而设定了大量的参数，这使得这些模型变得复杂，难以根据现有数据进行测试。在这里，我们概述了一种替代的数据驱动的逆方法。我们应用SCIMAP，一个简约的风险为基础的模型，有一个明确的治疗水文连通性。我们采取贝叶斯方法来确定风险，必须分配给不同的土地利用在一个集水区，以解释测量的流中营养盐浓度的空间格局的逆问题。我们应用该模型，以确定氮（N）和磷（P）的扩散污染风险的主要来源，在11个英国集水区，涵盖了一系列的景观。模型结果表明：1）某些土地利用产生的扩散性营养污染风险始终较高或较低; 2）不同土地利用的风险在集水区和营养物之间存在差异; 3）集水区磷和氮风险的主要来源通常是土地利用空间配置的函数。在个案基础上，这种逆向方法可用于帮助确定干预措施的重点，以减少淡水生态系统的扩散污染风险。
The hydrological and biogeochemical processes that operate in catchments influence the ecological quality of freshwater systems through delivery of fine sediment, nutrients and organic matter. Most models that seek to characterise the delivery of diffuse pollutants from land to water are reductionist. The multitude of processes that are parameterised in such models to ensure generic applicability make them complex and difficult to test on available data. Here, we outline an alternative – data-driven – inverse approach. We apply SCIMAP, a parsimonious risk based model that has an explicit treatment of hydrological connectivity. We take a Bayesian approach to the inverse problem of determining the risk that must be assigned to different land uses in a catchment in order to explain the spatial patterns of measured in-stream nutrient concentrations. We apply the model to identify the key sources of nitrogen (N) and phosphorus (P) diffuse pollution risk in eleven UK catchments covering a range of landscapes. The model results show that: 1) some land use generates a consistently high or low risk of diffuse nutrient pollution; but 2) the risks associated with different land uses vary both between catchments and between nutrients; and 3) that the dominant sources of P and N risk in the catchment are often a function of the spatial configuration of land uses. Taken on a case‐by‐case basis, this type of inverse approach may be used to help prioritise the focus of interventions to reduce diffuse pollution risk for freshwater ecosystems.