Collaborative Research: Cross-Scale Interactions Among Climate, Land-Use, and River-Water Quality

水质是世界上最宝贵的自然资源之一。考虑到最近和预计的气候变化（某些地区的干旱更加频繁和严重）和土地利用（与全球肉类、乳制品和林产品需求增加相关的农业集约化），了解气候和土地利用同时变化如何影响水质是很重要的。例如，干旱期间的农业集约化是否会增加流入河流的泥沙径流？这些影响在多大程度上发生？该项目将利用遥感和计算机可视化工具分析气候变化和土地利用之间的相互作用如何在多个相互作用尺度上影响河流水质：从几分钟到几十年，从小型集水区到区域流域。该研究将展示这些跨尺度的相互作用如何影响具有多维社会相关性的自然资源：水处理、娱乐、安全、旅游和生态系统健康。这项研究的结果将为新兴的美国数据监测网络提供信息，告诉他们应该在哪个空间和时间尺度上进行水样取样，以捕捉气候和土地利用之间的相互作用。项目结果和数据将通过各种方式向公众公布，包括开放获取期刊、公共网站和大学/高中研讨会。该项目将调查的一个基本问题是，气候和土地利用的同时变化是否会产生正反馈和连锁反应，从而导致河流水质发生巨大而广泛的变化。以往的研究未能在多个时空尺度上同时评估气候-土地利用相互作用对河流水质的影响，主要原因是：(1)缺乏能够同时分析多个维度和时空尺度的工具；(2)缺乏资源（即长期、一致的高分辨率水质数据集）；(3)缺乏技术（即以精细时空分辨率捕获土地覆盖变化的能力）。该项目通过使用(1)一套复杂的可视化工具进行组合分析，克服了这些限制；(2)世界上最全面、最广泛的水质数据集之一（25年气候数据）；(3)融合8天时间分辨率和30米空间分辨率的新西兰全国土地覆盖数据集。因此，这项研究将首次在多个时空尺度上同时评估气候和土地利用变化对一系列水质变量的相互影响。此外，应用复杂的视觉分析工具同时跨多个尺度研究景观动态可能会推动地理和空间科学的新范式。

Water quality is one of the world's most valued natural resources. Given recent and predicted changes in both climate (more frequent and intense droughts in some regions) and land use (agricultural intensification associated with increasing global demand for meat, dairy, and forestry products), it is important to understand how simultaneous changes in climate and land use affect water quality. For example, does agricultural intensification during a drought increase sediment runoff into rivers, and at what scales do these effects take place? This project will use remote sensing and computer visualization tools to analyze how interactions between shifting climate and land use affect river water quality across multiple interacting scales: from minutes to decades, and from small catchments to regional drainage basins. The proposed research will demonstrate how these cross-scale interactions affect a natural resource with multidimensional societal relevance: water treatment, recreation, safety, tourism, and ecosystem health. Findings from this research will inform emerging US data monitoring networks as to at which spatial and temporal scales water sampling should be conducted to capture interactions from climate and land use. Project results and data will be communicated to the public through various means, including open-access journals, a public website, and college/high school workshops. A fundamental question that this project will investigate is whether simultaneous shifts in climate and land use result in positive feedbacks and cascading events that lead to dramatic and widespread changes in river water quality. Previous studies have not been able to assess the effects of climate-land use interactions on river water quality over multiple spatial and temporal scales simultaneously due to (1) not having a toolkit that can analyze multiple dimensions and spatial-temporal scales simultaneously; (2) lack of resources (i.e., long-term and consistent water quality datasets with fine resolution); and (3) lack of technology (i.e., ability to capture land cover changes with fine spatial and temporal resolution). This project overcomes these limitations by using (1) a sophisticated set of visualization tools to analyze in combination; (2) one of the world's most comprehensive and extensive water quality datasets (25 years with corresponding climate data); and (3) a fused 8-day temporal resolution and 30-meter spatial resolution land cover dataset that has been developed for the entire country of New Zealand. Thus, this research will be the first time that the interactive effects of climate and land use changes on a suite of water quality variables will be assessed over multiple spatial-temporal scales simultaneously. Further, the application of sophisticated visual analysis tools to investigate landscape dynamics across multiple scales simultaneously could be the impetus for a new paradigm in Geography and Spatial Sciences.