EAR-PF: Constraining Paired Air-Water Temperature Models' Efficacy In Head and Intermediate Watersheds With Groundwater and Bedrock Assessment and Multi-Decade Temperature Records

气候变化使大气温度升高，从而改变地下水和溪流的温度模式，导致水质和生态多样性下降。在美国东部的部分地区，如西弗吉尼亚州，在过去的一个世纪里，气候已经变暖了0.5º- 1.0ºF，预计到2100年气温将再上升3º- 4ºF，进一步升高溪流和浅层地下水的温度，并影响生活在那里的生物。河流温度模式可以让我们深入了解这些河流和流域对变暖温度的脆弱性。然而，目前的模型并没有完全考虑到地表和地下水相互作用引起的温度变化。在不断变化的气候条件下，对地下水和地表水温度的模式预测必须考虑到影响热信号的因素，包括气候、地质、水文、土地利用和土地覆盖。数据显示，响应气候变化的河流温度变化可能（部分）是由相对贡献和排放地下水温度的变化所驱动的。自1958年以来，西弗吉尼亚州的弗诺实验森林（FEF）一直在记录至少10个水源流域的温度数据。利用FEF作为一个控制良好的室外实验室来研究这些温度模式，Riddell将产生改进的模型，并更好地了解这些系统。改进的模型可用于估计流域对干旱或高强度降水事件以及洪水等相关灾害的反应。通过与国家青少年科学基金会（NYSF）的合作，这项工作将直接影响到WV的初高中学生。这项提议的工作是在莫农加希拉国家森林进行的，自1963年以来，国家青年科学基金会一直在这里举办国家青年科学营。FEF靠近营地和新购买的位于西弗吉尼亚州戴维斯的国家青年科学中心（NYSCenter）。在这个项目中，与NYSF工作人员的合作将导致在黑水河上安装一个流量测量监测站，该监测站与nycenter相邻，为WV的初高中学生提供水文教育。这项合作将支持NYSF的使命，即建立和保持学生对STEM领域的兴趣，提高高中保留率和追求中学后STEM教育。气候变化使大气温度升高，改变了地下水和溪流的热模式，导致水质和生态多样性下降。地表水的热状态受到地下水及其与地表的连通性的高度影响，这可以通过比较空气和水流的温度记录来辨别。正弦波回归的成对空气-水温度分析是表征空气温度与地表水温度关系的一种方法，可以阐明地下水对流域水力学、冷水栖息地避难所和地下水温度对气候变化的响应的贡献。最近的研究主要集中在模拟每年成对的空气/水温度信号，以评估地下水在将空气温度从亚流域传播到大陆尺度的水流中的作用。这些正弦回归研究的结果集中在通过比较空气和水温记录的振幅比（正弦曲线峰高）和相位滞后信号（峰间时间）来确定地下水对地表水的输入和地表水对气候变化的最终响应。深层地下水特征显示年温度变化不大，振幅比和相位滞后不明确，而浅层地下水特征显示高振幅比和可测量的天级相位滞后。然而，目前的模型并没有完全考虑地下水-地表水相互作用对河流温度的影响。这些过程受含水层特征的控制，如含水层厚度、孔隙度、水力导电性、基岩类型和深度。本研究将利用WV的Fernow实验森林，通过收集新的地下水温度测量数据，评估同一流域中不同基岩地质的影响，并探索这些模型在水文连接、嵌套流域以及空气和河流温度记录存在数十年的流域中的有效性，来提高热流模型在小流域和中等流域中的有效性。这项研究将促进地下水对水源流域和中间流域的贡献以及这些流域对气候变化的脆弱性的认识。目前的模型（正弦回归）应用于大型大陆流域，认识到当地水文地质和地质对地下水行为及其对地表水流温度模式的后续影响的重要性。然而，目前还没有研究集中表征小流域的地表水文、水文地质和基岩地质，以及所有这些因素对河流温度模式的贡献。这项研究将填补这一空白，并强调在对地表进行预测时描述地下特征的重要性。本项目由地球科学博士后奖学金计划、促进竞争性研究的既定计划（EPSCoR）和水文科学计划共同资助。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Climate change increases atmospheric temperatures, which alters temperature patterns in groundwater and streams and results in reduced water quality and ecological diversity. In parts of the eastern United States, like West Virginia, climate has already warmed 0.5º – 1.0º F over the last century and temperatures are expected to rise another 3º – 4º F by the year 2100, further warming stream and shallow groundwater temperatures and affecting the organisms that live there. Stream temperature patterns provide insight into the vulnerability of these streams and watersheds to warming temperatures. However, current models do not fully account for temperature changes caused by interactions of water on the surface and underground. Model predictions of ground and surface water temperatures in a changing climate must be informed by the factors that influence thermal signals, including climate, geology, hydrology, land use, and land cover. Data show stream temperature changes in response to changing climate are likely driven (in part) by changes in relative contributions and temperatures of discharging groundwater. The Fernow Experimental Forest (FEF) in West Virginia has been recording temperature data in at least ten headwater watersheds since 1958. Using the FEF as a well-controlled outdoor laboratory to study these temperature patterns, Riddell will generate improved models and better knowledge of these systems. Improved models can be used to estimate watershed responses to drought or high intensity precipitation events, and associated disasters such as flooding. This work will directly impact middle and high school high school students in WV through collaboration with the National Youth Science Foundation (NYSF). This proposed work is in the Monongahela National Forest where the National Youth Science Foundation has hosted its National Youth Science Camp since 1963. The FEF is close to the camp and the newly purchased National Youth Science Center (NYSCenter) in Davis, WV. During this project, collaboration with NYSF staff will result in the installation of a stream gage monitoring station on the Blackwater River, which is adjacent to the NYSCenter to deliver hydrology education to middle and high school students in WV. This collaboration will support the NYSF mission to build and maintain student interest in STEM fields and promote high school retention rates and the pursuance of post-secondary STEM education.Climate change is increasing atmospheric temperatures which alters thermal patterns in groundwater and streams, resulting in reduced water quality and ecological diversity. Thermal regimes in surface waters are highly influenced by groundwater and its connectivity to the surface, which may be discerned by comparing air and stream temperature records. Paired air-water temperature analysis via sine wave regression is a way to characterize the relationship between air temperature and surface water temperature to elucidate the groundwater contributions to watershed hydraulics, cold-water habitat refugia, and groundwater temperature response to climate change. Recent research has focused on modeling annual paired-air/water temperature signals to assess the role of groundwater in propagating air temperature to stream water from sub-watershed to continental scales. Results of these sine regression studies are focused on determining the inputs of groundwater to surface water and the eventual response of surface water to climate change by comparing the amplitude ratios (sine curve peak height) and phase lag signals (time between peaks) of air and water temperature records. Deeper groundwater signatures show little variation in annual temperature and have ambiguous amplitude ratio and phase lag whereas shallow groundwater signatures show high amplitude ratios and measurable phase lag on the order of days. However, current models do not fully account for groundwater – surface water interactions that influence stream temperatures. These processes are governed by aquifer characteristics such as aquifer thickness, porosity, hydraulic conductivity, and bedrock type and depth. This study will utilize the Fernow Experimental Forest in WV to improve thermal stream model efficacy in small and intermediate watersheds by collecting new groundwater temperature measurements, assessing the influence of differing bedrock geology in the same watershed, and exploring the efficacy of these models in hydrologically connected, nested watersheds and in watersheds in which air and stream temperature records exist across multiple decades. This study will advance the knowledge of groundwater contributions to headwater watersheds and intermediate watersheds into which they discharge and to the vulnerability of these watersheds to climate change. The current models (sine regression) being applied to large, continental size watersheds recognize the importance of local hydrogeology and geology on groundwater behavior and the subsequent effects on surface stream temperature patterns. However, no study has yet to intensively characterize the surface hydrology, hydrogeology, and bedrock geology of small watersheds and the contribution of all these factors on stream temperature patterns. This study will fill that gap and highlight the importance of characterizing the subsurface when making predictions about the surface. This project is jointly funded by the Earth Sciences Postdoctoral Fellowship program, the Established Program to Stimulate Competitive Research (EPSCoR) and the Hydrologic Sciences program.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.