Hydrology-phosphorus interactions under changing climate and land-use: overcoming uncertainties and challenges for prediction to 2050 (Nutcat 2050)

该提案旨在利用英国可用的最新数据和建模方法，在2050年气候和土地利用变化情景下，促进我们对英国水源集水区水文和营养转移之间相互作用的理解和预测。研究集水区将是英国示范测试集水区（dtc），目标将通过以下方式实现：(1)使用现有的气候模型情景来设定变化的基线结果；(2)举办以dtc为重点的利益相关者启发研讨会，以制定应对气候情景的土地利用变化情景；(3)模拟当前水文事件和未来流域水文变化，以响应气候/土地利用的变化；(4)对极端水文条件下磷(P)行为的新认识，利用实验和最新的高分辨率dtc观测数据为模型开发提供信息；(5)由于对水文-磷相互作用的新认识，提高了对未来磷行为情景的预测（具有不确定性）；(6)尝试将信息源集水区扩展到全流域；(7)将模型性能与现有P模型进行比较，评估该过程中涉及的不确定性，并进一步进行利益相关者咨询。我们将重点关注10平方公里的规模，因为这与我们选择的研究区域Defra dtc的9个研究集水区（来自Eden， Wensum和Avon dtc）的规模相匹配；这个尺度也代表了沿着动员-交付-流影响“转移连续体”研究过程的理想尺寸。这些综合研究将产生养分通量的原型定量评估和预测。我们的假设是，风暴模式的季节性变异性增加（更极端的事件，更长的干旱期），再加上与土地利用变化的相互作用，将极大地改变未来陆地-水连续体中的溶解态和颗粒态磷通量，以及随后在河流和下游的富营养化风险。我们将扩展我们最初的“基于系统证据的评估方法（SEBAM）”研究，该研究侧重于农场规模的磷素动员（最近由该团队发表），并将其扩展为一个原型建模框架，该框架包括用于预测英国水源集水区磷素通量的来源、动员、输送和流内处理功能，并考虑土地利用变化。并使用这个框架（结合团队参与的其他项目的知识）扩大我们的信息，以确定在整个流域范围内预测其他营养行为的潜力。我们将利用新的、独特的高质量、高时间分辨率的P监测数据，这些数据开始从九个Defra DTC子集水区出现。这项工作的一个独特和令人兴奋的方面将是使用专家启发程序，结合基于模糊不确定性的分析，为9个DTC重点集水区的每个独特景观类型开发量身定制的土地使用场景（建立在英国土地使用展望倡议的基础上）。将这些信息与英国的最新气候情景相结合，我们将包括高分辨率数值天气预报的新发展。然后，我们将利用这些情景研究到2050年气候和土地利用变化对水文、磷动员、输送和河流处理的影响，并从新的经验学习和实验中获得信息。然后，模型输出将使用相关项目和我们的合作伙伴的数据，在更广泛的英国（康威，里布尔，塔兰）的其他集水区进行验证。在整个项目中，将与利益相关者一起测试结果。这将提供一个当地拥有的基于知识的框架，用于理解和管理未来农村流域系统的养分转移，以及一些关于磷转移的令人兴奋的新科学。

The proposal aims to advance our understanding and predictions of interactions between hydrology and nutrient transfers in headwater catchments in the UK, under climate and land use change scenarios to 2050, using the very latest data and modeling approaches available for the UK. The study catchments will be the UK Demonstration Test Catchments (DTCs) and the aims will be achieved through: (1) using existing climate model scenarios to set baseline outcomes for change; (2) localized DTC-focused stakeholder elicitation workshops to develop scenarios for land use changes in response to the climate scenarios; (3) simulating current hydrological events and future changes in catchment hydrology in response to changing climate/land use; (4) new understanding of phosphorus (P) behaviour in extreme hydrological conditions, using experiments and newly available high resolution observations from the DTCs to inform model development; (5) improved prediction (with uncertainty) of future P behaviour scenarios arising from the new understanding of hydrology-P interactions; (6) attempting to scale up the information from headwater-catchment to full basin scale, and; (7) compare model performance with existing P models and assess uncertainties involved in this process, with further iterations of stakeholder consultation. We shall focus on the 10 km2 scale because this matches the size of the nine study catchments of the Defra DTCs (from the Eden, Wensum and Avon DTCs), which are our chosen study areas; this scale also represents the ideal size for studying processes along the mobilisation-delivery-in-stream impact 'transfer continuum'. These integrated studies will produce a prototype quantitative assessment and prediction of nutrient fluxes. Our hypothesis is that increased seasonal variability in storm patterns (more extreme events, long drought periods), combined with interactions with land use change, will greatly alter future dissolved and particulate P fluxes across the land-water continuum and subsequent retention in-stream and downstream eutrophication risk. We shall extend our initial 'Systems Evidence Based Assessment Methodology (SEBAM)' study that focused on mobilization of P at the farm scale (recently published by the team), into a prototype modeling framework that includes source, mobilization, delivery and in-stream processing functions for predicting P fluxes from UK headwater catchments, and considers land use change, and use this framework (combined with knowledge from other projects involving the team) to scale up our information to define the potential for predicting other nutrient behaviours at the full basin scale. We will capitalize on the new and unique high quality, high temporal resolution P monitoring data that is starting to emerge from the nine Defra DTC sub-catchments. A unique and exciting aspect of the work will be the use of expert elicitation procedures that incorporate fuzzy uncertainty-based analyses to develop tailored land use scenarios (building on the UK Land Use Foresight Initiative) for each of the unique landscape typologies for the 9 DTC focus catchments. Combining this information with the latest climate scenarios for the UK, we will include new developments in high-resolution numerical weather prediction. We shall then use these scenarios to study the impacts of climate and land use change to 2050 on hydrology, P mobilization, delivery and in-stream processing, informed from new empirical learning and experimentation. Model outputs will then be validated for other catchments in the wider UK (Conwy, Ribble, Tarland) using data from linked projects and our partners. Throughout the project, the outcomes will be tested with stakeholders. This will deliver a locally owned knowledge-based framework for understanding and managing future nutrient transfers from rural catchment systems, and some exciting new science on P transfers.