Real-Time Flood Forecasting Based on a High-Performance 2-D Hydrodynamic Model and Numerical Weather Predictions
Real-Time Flood Forecasting Based on a High-Performance 2-D Hydrodynamic Model and Numerical Weather Predictions
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DOI：
10.1029/2019wr025583
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发表时间：
2020-07-01
影响因子：
5.4
通讯作者：
Fowler, Hayley J.
中科院分区：
文献类型：
--
作者：
Ming, Xiaodong;Liang, Qiuhua;Fowler, Hayley J.
洪水预报系统通常由至少两个基本组成部分组成，即提供降雨预报的数值天气预报（NWP）模型和预测水文响应的水文/水力模型。水文模型虽然广泛用于洪水预报，但由于忽视了严格的动量守恒，只能提供洪水物理过程的简化表示。他们无法可靠地预测强降雨造成的高度瞬态洪水过程，在这种情况下，需要完整的二维水动力模型。由于高计算需求，尚未利用水动力模型来支持以足够高分辨率对大型流域进行实时洪水预报。为了填补当前研究和实践空白，本工作开发了一种新的预报系统，将图形处理单元（GPU）加速水动力模型与数值天气预报产品相结合，为强降雨引起的降雨径流和洪水过程提供高分辨率、流域尺度的预报。该新预报系统的性能经过测试并得到证实，将其应用于以 10 米分辨率“预报”2,500 公里(2) 流域内的极端洪水事件。对水位和洪水范围的数值预测和现场测量进行了定量比较。为了产生与观测结果良好比较的模拟结果，新的洪水预报系统在天气预报提前 36 小时提供的情况下提供了 34 小时的提前时间。数值实验进一步证实，在这种情况下，降雨输入的不确定性不会被水动力模型放大到最终的洪水预报输出。
A flood forecasting system commonly consists of at least two essential components, that is, a numerical weather prediction (NWP) model to provide rainfall forecasts and a hydrological/hydraulic model to predict the hydrological response. While being widely used for flood forecasting, hydrological models only provide a simplified representation of the physical processes of flooding due to negligence of strict momentum conservation. They cannot reliably predict the highly transient flooding process from intense rainfall, in which case a fully 2-D hydrodynamic model is required. Due to high computational demand, hydrodynamic models have not been exploited to support real-time flood forecasting across a large catchment at sufficiently high resolution. To fill the current research and practical gaps, this work develops a new forecasting system by coupling a graphics processing unit (GPU) accelerated hydrodynamic model with NWP products to provide high-resolution, catchment-scale forecasting of rainfall-runoff and flooding processes induced by intense rainfall. The performance of this new forecasting system is tested and confirmed by applying it to "forecast" an extreme flood event across a 2,500-km(2)catchment at 10-m resolution. Quantitative comparisons are made between the numerical predictions and field measurements in terms of water level and flood extent. To produce simulation results comparing well with the observations, the new flood forecasting system provides 34 hr of lead time when the weather forecasts are available 36 hr beforehand. Numerical experiments further confirm that uncertainties from the rainfall inputs are not amplified by the hydrodynamic model toward the final flood forecasting outputs in this case.