Collaborative Research: Scaling and Allometry in River Networks: Coupling Rainfall, Topography, and Vegetation with Hydrological Extremes

0001249 Krakenski本研究的长期目标是发展一个异速水文尺度理论的流域，可应用于全球排水网络。 我们定义水文异速生长标度是指存在的经验幂律关系的水文，生态，地形和大气变量和质量的水被输送在排水网络或物理相关的时空尺度。 本研究的目的是综合各种各样的不同的经验观测在一个广泛的理论框架内，本建议的第一个主要目标是制定一个理论外推观测到的流量时间序列从几个稀疏位于流测量站到ungauged的位置定义完整的Strahler流。 空间外推法要求将径流时间序列分为峰、枯水时间序列，因为在基于物理的滤波器中，不同的时间尺度涉及到径流的产生和输运，从而将实测点的枯水与峰流量分离开来。 将利用现有的降雨量、蒸发量和测量流量的现场测量结果对该过滤器进行诊断测试。 作为这些诊断研究的一部分，将使用一个坡面径流生成过程的综合数值模型来测试过滤器。 另一个关键步骤是发展一个可测试的时空理论，以在渠道网络中路由水。 我们的方法将尝试结合联合收割机的水力几何观察，流体力学的原则，如质量守恒，和随机自相似性最近报道的拓扑结构中的通道网络的属性。 第二个目标是扩展目标1中的结果，以纳入降雨、蒸散和径流生成过程中空间变异的影响。 这一目标将分两步进行研究。 首先是估计一平方米的时空降雨量。公里.像素每6分钟使用WSR-88 D雷达估计。 蒸发蒸腾量（ET）和软水分在生根区将估计从遥感产品，如，中分辨率成像光谱仪（MODIS）。 第二步将是测试敏感性的过滤器和路由目标1中开发的降雨量，蒸散量和径流产生的空间变异，使用这些遥感产品。 研究了遥感产品中误差结构对滤波和路由的影响。 将这些结果与目标1下获得的结果进行比较，以了解滤波器和路由对遥感产品误差的鲁棒性。 我们将在几个选定的盆地上测试目标1和2，例如，弗林特在格鲁吉亚，这是大约7,000平方米。公里. 现有的数字高程模型（DEM）将被用来提取网络结构的地貌分析。 从长远来看，需要对作为“天然实验室”的几个盆地进行涉及新测量的“概念测试”，但现场测试不在本提案的范围内。 这两个目标的进展将作出贡献的经典，长期以来，未解决的水文问题预测从无资料流域（PUB）。我们的第三个目标是调查经验异速生长标度关系，并评估时空尺度上的标度举行。 适当的生物物理约束，包括大气，地形，水和植被的耦合将被确定为河流网络。 我们会就这个目标进行一些探索性的研究。 新的航天飞机雷达地形使命（SRTM）和MODES产品分别提供全球地形和植被数据集。 基于卫星的时空降雨量估计在这一点上似乎不太有吸引力，主要是由于其较差的空间和时间分辨率，但这种情况将在未来改变。 利用这些遥感产品开发和测试这一理论将使今后探索全球网络的应用成为可能。

0001249KrajewskiThe long-term goal of this research is to develop an allometric-hydrologic scaling theory for drainage basins, which can be applied to global drainage networks. We define hydrologic-allometry scaling to mean the existence of empirical power-law relationships among hydrological, ecological, topographical and atmospheric variables and mass of water being transported in drainage networks or physically relevant space-time scales. This research aims to synthesize a wide variety of disparate empirical observations within a broad theoretical framework.The first major objective of this proposal is to develop a theory for extrapolating observed streamflow time series from a few sparsely located stream gauging stations to ungauged locations defined by complete Strahler streams. Spatial extrapolation requires that streamflows be separated into peakflow and lowflow time series because different time scales are inolved in runoff generation and transport in physically based filter to separate lowflows from peakflows of gauged locations. Diagnostic tests of this filter will be carried out using available in-situ measurements of rainfall, evaporation and gauged streamflows. An integrated numerical model of runoff generation processes from a hillslope will be used to test the filter as part of these diagnostic studies. Another key step is to develop a testable space-time theory to route water in channel networks. Our approach will attempt to combine observations of hydraulic geometry, principles of fluid mechanics such as conservation of mass, and property of random self-similarity recently reported in the topology of channel networks. The second objective is to extend the results in objective 1 to incorporate the effect of spatial variability in rainfall, evapotranspiration and runoff generation processes. This objective will be investigated in two steps. First will be to estimate space-time rainfall at one sq. km. Pixels every 6 minutes using WSR-88D radar estimates. Evapotranspiration (ET) and soft moisture in the rooting zone will be estimated from remotely sensed products, e.g., moderation resolution imaging spectrometer (MODIS). Second step will be to test the sensitivity of the filter and the routing developed in Objective 1 to spatial variability in rainfall, evapotranspiration, and runoff generation, using these remotely sensed products. Effect of error structure in remotely sensed products on the filter and the routing will be investigated. Comparisons of these results with those obtained under Objective 1 will be carried out to understand the robustness of the filter and routing to errors in remotely sensed products. We will test Objectives 1 and 2 on a few selected basins, e.g., Flint in Georgia, which is about 7,000 sq. km. The existing digital elevation models (DEM) will be used to extract network structure for geomorphologic analysis. In the long run, a 'test of the concept' involving new measurements is needed for a few basins serving as 'natural laboratories,' but field tests are outside the scope of this proposal. Progress on these two objectives will make contributions toward the classic, long-standing, unsolved hydrology problem of Prediction from Ungauged Basins (PUB).Our third objective is to investigate empirical allometric-scaling relationships, and assess space-time scales over which scaling holds. Suitable biophysical constraints involving the coupling of atmosphere, terrain, water, and vegetation will be identified for river networks. We will carry out some exploratory studies on this objective. The new Shuttle Radar Topographic Mission (SRTM) and MODES products provide global topographic and vegetation data sets respectively. Satellite-based estimates of space-time rainfall seems less attractive at this point mainly due to their poorer spatial and temporal resolution but this situation would change in the future. Use of these remotely sensed products in developing and testing this theory would make it feasible to explore applications to global networks in the future.