Global river slope: A new geospatial dataset and global-scale analysis
Global river slope: A new geospatial dataset and global-scale analysis
复制标题
DOI：
10.1016/j.jhydrol.2018.06.066
复制
发表时间：
2018-08-01
影响因子：
6.4
通讯作者：
Syvitski, J. P. M.
中科院分区：
文献类型：
--
作者：
Cohen, Sagy;Wan, Tong;Syvitski, J. P. M.
河流的纵比降（即坡度）是河流水文学、水力学和地貌学中的一个关键参数。它影响了许多河流变量，如流速和泥沙输运。河流坡度数据的可用性和准确性限制了河流建模的保真度，特别是在更大或全球尺度上。传统的坡度计算算法是基于逐单元计算的，只适用于山坡和山区小溪流，无法准确预测河流坡度。本文提出了一种计算全球河流坡度的方法，并提出了一种将其提高到相对粗分辨率的方法，适用于全球尺度模拟。该方法是基于一个简单的原则，计算坡度的高程下降超过一个河段的长度，这是自动化，以允许全球规模的计算。版本1.0的全球河流坡度（GloRS）地理空间数据集的介绍，并显示是一个步骤的改进，比以前的产品（NHDplus的连续的美国），并比较有利的观察到的斜率数据从文献中收集。对地球大陆和大盆地的统计分析突出了有趣的空间趋势。流域平均河流坡度和其他流域尺度参数之间的半经验回归分析表明，地形坡度占流域平均河流坡度变化的67%，平均流量，泥沙负荷和流域温度分别为3%，4%和3%的全球预测贡献额外的改进。
A rivers' longitudinal gradient (i.e. slope) is a key parameter in fluvial hydrology, hydraulics, and geomorphology. It affects a multitude of fluvial variables such as flow velocity and sediment transport. Limitations in river slope data, both its availability and accuracy, constrain the fidelity of fluvial modeling, particularly at larger or global scales. Traditional slope calculation algorithms cannot accurately predict river slopes as these are based on cell-by-cell calculation, which is only suitable for hillslopes and small mountainous streams. This paper presents a methodology for calculating global river slope and a procedure to upscale it for relatively coarse resolution, suitable for global scale modeling. The methodology is based on a simple principle of calculating slope from elevation depression over the length of a river segment, which is automated to allow global scale calculations. Version 1.0 of the Global River-Slope (GloRS) geospatial dataset is introduced and shown to be a step improvement over a previous product (NHDplus for the contiguous United States) and compares favorably to observed slope data collected from the literature. Statistical analysis of Earth's continents and large basins highlights interesting spatial trends. A semi-empirical regression analysis between basin-average river slope and other basin-scale parameters show that terrain slope accounts for 67% of the variability in basin-average river slope, with average discharge, sediment load and basin temperature contributing additional improvements to global predictions of 3%, 4%, and 3%, respectively.