CAREER: Modeling 19th century estuaries to address 21st century problems

解决21世纪的问题，如沿海洪水、海平面上升和盐度入侵，需要了解潮汐和水位的长期趋势和空间格局。为了充分评估和解释长期趋势的原因，需要进行历史观测和对历史条件进行回顾性模拟。本研究将使用可验证的数据来研究哥伦比亚河河口潮汐和运输的长期动态，以阐明系统的敏感性。众所周知，潮汐动力学和标量传输的理想见解将在复杂的环境中进行测试，以测试当地地形，湿地面积和深度的变化如何产生物理变化。所提出的动力学问题可能对全球河口的过去发展和未来轨迹产生影响。该项目将培训一名研究生，并让高中教师和代表性不足的学生参与其中。这项研究利用了正在进行的19世纪数据数字化的努力和最近开发的历史哥伦比亚河河口的数值模型。通过开拓校准历史模型和通过历史/现代模型比较评估时空趋势的新方法，该项目将为未来在其他强烈变化河口的类似研究奠定基础。利用1854年以来的水温时间序列，通过模拟历史水温，开辟了新的领域。因为水温和盐度一样，是沿河流/海洋连续体混合的，它将用于校准和验证历史和现代模型中的盐度入侵。这种方法避免了历史盐度数据的缺乏，提高了模型的保真度，并允许基于过程的研究来确定改变水位、栖息地淹没、斜压环流和运输的历史因素。主要的假设是：(a)自19世纪以来，直接的人为改变，而不是气候引起的河流流量或海平面的变化，主导了河口功能的变化；(b)过去的水温和盐度变化比现在大得多，但流量和河道深度的变化增加了盐度入侵；(c)潮汐河中潮汐传播的变化将反映在洪水波传播的改变上，洪水波的移动速度将比过去更快，分散更少。

Addressing 21st century problems such as coastal flooding, sea-level rise, and salinity intrusion requires understanding both long-term trends and spatial patterns in tides and water level. Historical observations and retrospective modeling of historical conditions are needed to fully evaluate and interpret the cause of long term trends. This study will investigate the long-term dynamics of tides and transport in the Columbia River Estuary using verifiable data to elucidate system sensitivities. Well-known, idealized insights into tidal dynamics and scalar transport will be tested in a complex environment, to test how altered local topography, wetland area, and depth have produced physical changes. The dynamical questions raised may have implications for the past development and future trajectory of estuaries globally. The project will train a graduate student and engage High School teachers and underrepresented students.This study leverages ongoing efforts to digitize 19th century data and a recently developed numerical model of the historic Columbia River Estuary. By pioneering new ways of calibrating historical models and evaluating spatio-temporal trends via historical/modern model comparison, this project will lay the groundwork for similar, future research in other strongly-altered estuaries. Using time series of water temperature back to 1854, new ground will be broken by simulating historical water temperatures. Because water temperature, like salinity, is mixed along the river/ocean continuum, it will be used to calibrate and verify salinity intrusion in both historical and modern models. This approach circumvents the lack of historical salinity data, increases model fidelity, and allows for process-based studies to determine the historical factors which have altered water levels, habitat inundation, baroclinic circulation, and transport. The primary hypotheses are: (a) Direct anthropogenic alterations, rather than climate induced changes to river flow or sea level, have dominated changes to estuary functioning since the 19th century; (b) water temperature and salinity variability was much larger in the past than today but changes in flow and channel depth have increased salinity intrusion; and (c) changes in tide propagation in the tidal river will be reflected in altered flood wave propagation: flood waves will move faster, and disperse less, than in the past.