Doctoral Dissertation Research: Hydroclimate Reconstructions of the Potomac River Basin Using Tree Rings

树木年轮分析是一门研究树木年轮的科学，它使科学家能够对每年或季节性的数据进行精确的日期记录，这些数据通常可以追溯到过去300年或更长时间。在仪器数据记录较短的地区，树木的生长可以作为径流的替代品，因为影响河流的许多相同因素，如降水和径流，也会影响树木的生长。与美国西部和中部不同，美国东部的树木年轮记录有限，适合重建千年径流和气候。美国东部气候历史的一个新来源可能来自西弗吉尼亚州波托马克河源头附近生长的古老的东部红杉的孤立林。此外，在东部阔叶林中，数十种树种在不同的地点共同生长，每种树种对气候的反应都不同，从而可以提取更多的气候信息。这项研究将利用古老的东部红杉和众多的阔叶树种，以了解更多关于流域径流和气候的历史。波托马克河流域目前的管理和建模策略受到流量和降水的仪器记录的有限长度和可变性的限制。该项目的主要成果将是：1）使用东部红雪松树轮宽度重建波托马克河流域过去1000年的径流和降水，2）用于增加过去300年气候季节知识的多物种树轮重建，3）在过去1000年的树木年轮记录的背景下，流量的仪器记录的评价，和4）在美国东部的水资源建模工作的树木年轮数据的整合。这个博士论文研究将产生少数超长（1000年）的树木年轮年表北美东部之一。波托马克河是华盛顿大都会区的主要水源，约占用水需求的75%。气候重建将有助于波托马克河流域州际委员会的水资源管理人员通过将流量和降水的仪器记录放在过去一千年的自然气候变化的背景下来规划未来的干旱事件。将把降水和径流的树木年轮记录纳入现有的水供应和需求模式，以评估水系统在过去干旱情况下满足需求的能力。多物种方法将帮助树木年轮科学家在存在多个物种的其他地区进行气候重建，并将促进利用现有的树木年轮数据来调查仪器记录有限的地方的水资源管理问题。作为博士论文研究改进奖，该奖项还将提供支持，使有前途的学生建立一个强大的独立的研究生涯。

Tree-ring analysis, the science that deals with study of annual tree rings, allows scientists to develop precisely dated records of annually or seasonally resolved data commonly extending 300 or more years into the past. In regions with short records of instrumental data, tree growth can be used as a substitute for streamflow because many of the same factors that affect streams, such as precipitation and runoff, also influence the growth of trees. Unlike the western and central United States, the eastern United States has limited tree-ring records suitable for millennial-length reconstructions of streamflow and climate. A new source of climate history for eastern United States may be derived from isolated stands of old-growth eastern redcedar growing near the headwaters of the Potomac River in West Virginia. Additionally, in the eastern broadleaf forest tens of tree species grow together across a variety of sites, each with a different response to climate, allowing for additional climate information to be extracted. This research will utilize old-growth eastern redcedar and the multitude of broadleaf tree species to learn more about the history of streamflow and climate in the Basin. Current management and modeling strategies in the Potomac River Basin are constrained by the limited length and variability of the instrumental records of streamflow and precipitation. The primary outcomes of the project will be 1) tree-ring reconstructions of the streamflow and precipitation of the Potomac River Basin for the last 1000 years using eastern redcedar tree-ring widths, 2) a multi-species tree-ring reconstruction used to increase the seasonal knowledge of climate for the last 300 years, 3) an evaluation of the instrumental record of streamflow in the context of the past 1000 years of the tree-ring record, and 4) the integration of tree-ring data into water resource modeling efforts in the eastern United States. This Doctoral Dissertation Research will generate one of the few ultra-long (1000 years) tree-ring chronologies for eastern North America. The Potomac River is the primary water resource for the Washington, DC metropolitan area, supplying approximately 75 percent of the water demand. The climate reconstructions will aid water resource managers at the Interstate Commission on the Potomac River Basin plan for future drought events by placing the instrumental records of streamflow and precipitation within the context of natural climatic variability of the past millennium. The tree-ring records of precipitation and streamflow will be integrated into an existing water supply and demand model to assess the ability of the water system to meet demand under past drought conditions. The multi-species approach will aid tree-ring scientists in climate reconstructions in other regions where multiple species are present and will promote the use of existing tree-ring data to investigate water resource management issues in locations with limited instrumental records. As a Doctoral Dissertation Research Improvement award, this award also will provide support to enable a promising student to establish a strong independent research career.