Seasonal to Decadal Variability in Discharge & Dissolved Solids in the Colorado River Basin: The Climate-Groundwater System

9805035达菲这项研究提出调查历史河流流量和溶解固体记录从独特的地形的科罗拉多河流域（CRB）。 研究的目的是开发一个检测和模拟策略的大尺度流域响应低频气候强迫（年际和十年的时间尺度）和长期的趋势，从自然和人为起源。 CRB的特征地形，以盆地上部的科罗拉多高原和盆地下部的盆地和山脉自然地理为代表，用于定义整个区域流体和溶质储存的自然空间和时间尺度;而灌溉和水库运行的土地利用实践修改了自然和水化学“信号”。 一个需要解决的重要问题是“作为土地利用、地形和水文地质条件的函数，溶解固体排放的最小状态空间维数是多少，以及它们与长期气候强迫的关系如何。 数据库是：从绿色河和科罗拉多河上游到加州湾分布的20个站点40-60年的月平均流量和河流化学;流域和邻近高原和山脉的月降水温度记录;灌溉和非灌溉地区的地下水位以及数字地形和土地利用数据。将使用两种方法从含噪水化学数据中提取时空信号：用于空间模态分析的主成分分析和用于检测时间振荡的奇异谱分析。 我们最近发表在《水资源研究》（Duffy，1996; Duffy和Cusumano，1998; Shun和Duffy，1998）上的研究涉及从水化学变量的地形平均和基本偏微分方程制定动态模型。 这项研究将形成一个实际的，低维的模拟策略，试图平衡的程度模型的复杂性与一个可定义的水平的建模技巧，并评估年际和年代际气候振荡对水资源的CRB测试的基础。

9805035DuffyThis research proposes to investigate historical river discharge and dissolved solids records from the unique landform of the Colorado River Basin (CRB). The purpose of study is to develop a detection and modeling strategy for large-scale basin response from low-frequency climate forcing (interannual and decadal time scales) and secular trends from natural and anthropogenic origin. The characteristic terrain of the CRB, represented by the Colorado plateau in the upper basin and the Basin and Range physiography in the lower basin, serves to define the natural space and time scales of fluid and solute storage across the region; while landuse practices of irrigation and reservoir operation modify the natural and hydrochemical "signal). An important question to be addressed is "what is the minimum state-space dimension of dissolved solids-discharge as a function of landuse, landform and hydrogeologic conditions, and how do they relate to long term climate forcing. The data base is: 40-60 years of monthly average streamflow and stream chemistry for 20 stations distributed from the upper Green and Colorado rivers to the Gulf of California; monthly precipitation-temperature records across the basin and adjacent plateaus and ranges; groundwater levels in irrigated and nonirrigated regions as well as digital terrain and landuse data. Two methods for extracting space-time signal from noisy hydrochemical data will be used: principal component analysis for spatial modal analysis and, singular spectrum analysis for detection of temporal oscillations. Our recent research published in Water Resources Research (Duffy, 1996; Duffy and Cusumano, 1998; Shun and Duffy, 1998) has involved formulation of dynamical models from terrain averaging of hydrochemcial variables and underlying partial differential equations. The study will form the basis for testing a practical, low-dimensional modeling strategy for the CRB which attempts to balance the degree of model complexity with a definable level of modeling skill, and to evaluate the effect of interannual and decadal climate oscillations on the water resources of the CRB.