A physically based description of floodplain inundation dynamics in a global river routing model
A physically based description of floodplain inundation dynamics in a global river routing model
复制标题
DOI：
10.1029/2010wr009726
复制
发表时间：
2011-04-01
影响因子：
5.4
通讯作者：
Oki, Taikan
中科院分区：
文献类型：
--
作者：
Yamazaki, Dai;Kanae, Shinjiro;Oki, Taikan
目前的全球河流演变模型不能真实地代表洪泛区淹没动态，因为地表沃茨的储存和运动受小尺度地形的影响，而不是全球模型常用的空间分辨率。在这项研究中，我们提出了一个新的全球河流路由模型，CaMa-Flood，明确参数化的子网格尺度地形的洪泛区，从而描述洪泛区淹没动态。模型中的蓄水量、水位和淹没面积之间的关系是根据基于1 km分辨率数字高程模型的亚网格尺度地形参数确定的。采用扩散波方程计算水平输运，实现了平坦流域的回水效应。一组全球尺度的河流流量模拟表明，通过纳入洪泛区淹没动态，世界上许多主要河流的日尺度河流流量的可预测性有所提高。对亚马逊河模拟结果的详细分析表明，扩散波方程的引入对于逼真地模拟水面高程是必不可少的。模拟的亚马逊河流域洪水淹没面积的时空变化与卫星观测结果有很好的相关性，特别是当考虑回水效应时。该模型对河流日流量、水面高程和淹没面积的预测能力的提高将促进气候系统研究和水资源评估。
Current global river routing models do not represent floodplain inundation dynamics realistically because the storage and movement of surface waters are regulated by small-scale topography rather than the commonly used spatial resolution of global models. In this study, we propose a new global river routing model, CaMa-Flood, which explicitly parameterizes the subgrid-scale topography of a floodplain, thus describing floodplain inundation dynamics. The relationship between water storage, water level, and flooded area in the model is decided on the basis of the subgrid-scale topographic parameters based on 1 km resolution digital elevation model. Horizontal water transport is calculated with a diffusive wave equation, which realizes the backwater effect in flat river basins. A set of global-scale river flow simulations demonstrated an improved predictability of daily-scale river discharge in many major world rivers by incorporating the floodplain inundation dynamics. Detailed analysis of the simulated results for the Amazon River suggested that introduction of the diffusive wave equation is essential for simulating water surface elevation realistically. The simulated spatiotemporal variation of the flooded area in the Amazon basin showed a good correlation with satellite observations, especially when the backwater effect was considered. The improved predictability for daily river discharge, water surface elevation, and inundated areas by the proposed model will promote climate system studies and water resource assessments.