Refinement of Historical Variability and the Baseline for Hydroclimatic Conditions within the Walker Basin: A Multi-Elevational Dendrochronological and Ecohydrological Approach

水文气候变化是美国和世界干旱和半干旱地区供水规划的一个日益重要的方面。我们对相关时间尺度（即十年到百年）过去过程的理解通常来自高分辨率的古记录，如树木年轮。这项研究项目将使用树木年轮记录量化湿和干的插曲内的步行者河流域在西部内华达州/东部加州。沿着收集从现在起超过1000年的长年轮年表，该项目将在多个研究地点建立气候和生态方面的基线条件。为了捕捉树木年轮对单个水文气候变量（如夏季温度和冬季降水）的响应，研究人员将针对不同海拔范围内的四种树种以及多个地形方面。将在每个研究地点进行基线生态调查，以比较大盆地地区广泛的其他调查地点的条件。研究人员将使用原位的自由空气温度传感器，以更好地解释与模拟和区域气候数据相关的微观条件。一个气候监测站将安装在高海拔地区的一个孤立的部分流域，这将不仅捕捉温度和降水，而且太阳辐射，风模式和土壤条件。生态和感官数据将有助于解释古气候记录，因为流域中大部分针叶林区的现有数据仅限于建模产品。该项目的主要目标是重建季节性气候变量，这些变量将作为过去1200年来水平衡模型的输入，这段时间内，根据以前的树木年轮和湖泊沉积物研究，已经出现了巨大的变化。在过去的时间内，超过了我们的现代观测包络的流域行为的评价将有助于水管理者和用户的决策和规划，因为我们进入一个不确定的未来。过去过程的记录显示了景观如何对气候和能量输入的变化做出反应，无论未来条件变化的原因如何，了解干旱和半干旱环境中的流域动态至关重要。这种研究方法将加强树木年轮科学的知识，增加我们对流域尺度气候变化的理解，并澄清树木年轮记录和水预算之间的关系。该项目的重建结果将立即用于步行者盆地和邻近流域的科学家、水管理人员和水用户。通过该项目的调查和安装获得的气候和生态数据将提供给广泛的公众用户，并实时提供传感器数据。通过汇集联邦，大学和社区学院的研究人员，这个项目提供了一个独特的机会，跨不同层次的合作和推广。教育机会将提供给研究生，本科生和社区学院的学生，他们将能够参加现场和实验室工作以及科学会议。

Hydroclimatic variability is an increasingly important aspect of water supply planning in arid and semi-arid regions of the United States and the world. Our understanding of past processes at relevant timescales (i.e. decadal to centennial) is often derived from high resolution palaeorecords such as tree rings. This research project will use tree-ring records to quantify wet and dry episodes within the Walker River watershed in western Nevada/eastern California. Along with the collection of long tree-ring chronologies that will stretch from the present back over 1000 years, this project will establish baseline conditions at multiple study sites with respect to climate and ecology. To capture tree-ring responses to individual hydroclimatic variables, such as summertime temperatures and wintertime precipitation, the researchers will target four tree species across a range of elevations as well as multiple topographic aspects. Baseline ecological surveys will be conducted at each study site to allow for comparison of conditions among a wide range of other surveyed locations across the Great Basin region. The researchers will use in-situ, free-air temperature sensors to better interpret microsite conditions relative to modeled and regional climate data. A climate monitoring station will be installed at high elevation in an isolated portion of the watershed, which will capture not only temperature and precipitation, but also solar radiation, wind patterns, and soil conditions. Both the ecological and sensory data will aid interpretation of palaeoclimate records, as existing data for most of the conifer zones in the watershed are limited to modeling products. A primary goal of this project is to reconstruct seasonal climate variables which would serve as inputs to water balance modeling over the last 1200 years, a time period which has seen tremendous variability based on previous tree-ring and lake sediment studies. Evaluation of watershed behavior during past time periods that exceed the envelope of our modern observations will aid water managers and users in decision making and planning as we move into an uncertain future. Records of past processes show how landscapes respond to variations in climatic and energy input, and regardless of the cause of future changes in conditions, it is critical to understand watershed dynamics in arid and semi-arid environments. This research approach will bolster knowledge in tree-ring science, increase our understanding of climatic variability at the watershed scale, and clarify relationships between tree-ring records and water budgets. Reconstruction results from the project will be of immediate use to scientists, water managers, and water users within the Walker Basin and adjacent watersheds. Climatic and ecological data acquired as a result of the project's surveys and installations will be available to a wide range of public users, with sensor data provided in real-time. By bringing together Federal, University, and Community College researchers, this project provides a unique opportunity for collaboration and outreach across diverse levels. Educational opportunities will be provided to graduate, undergraduate, and Community College students, who will be able to participate in field and laboratory work as well as scientific conferences.