Large-scale flood modeling and forecasting with FloodCast

TL;DR

FloodCast introduces a novel, scalable flood modeling framework combining multi-satellite data and a geometry-adaptive neural solver, achieving high accuracy and efficiency for large-scale flood prediction and hazard warning.

Contribution

The paper presents GeoPINS, a physics-informed neural network that is resolution-invariant and geometry-adaptive, enabling fast and accurate large-scale flood modeling without training data.

Findings

GeoPINS outperforms traditional hydrodynamic models in flood prediction accuracy.

Sequence-to-sequence GeoPINS effectively models long-term flood dynamics.

The framework demonstrates high transferability and validation accuracy across different flood scenarios.

Abstract

Large-scale hydrodynamic models generally rely on fixed-resolution spatial grids and model parameters as well as incurring a high computational cost. This limits their ability to accurately forecast flood crests and issue time-critical hazard warnings. In this work, we build a fast, stable, accurate, resolution-invariant, and geometry-adaptative flood modeling and forecasting framework that can perform at large scales, namely FloodCast. The framework comprises two main modules: multi-satellite observation and hydrodynamic modeling. In the multi-satellite observation module, a real-time unsupervised change detection method and a rainfall processing and analysis tool are proposed to harness the full potential of multi-satellite observations in large-scale flood prediction. In the hydrodynamic modeling module, a geometry-adaptive physics-informed neural solver (GeoPINS) is introduced, benefiting from the absence of a requirement for training data in physics-informed neural networks and featuring a fast, accurate, and resolution-invariant architecture with Fourier neural operators. GeoPINS demonstrates impressive performance on popular PDEs across regular and irregular domains. Building upon GeoPINS, we propose a sequence-to-sequence GeoPINS model to handle long-term temporal series and extensive spatial domains in large-scale flood modeling. Next, we establish a benchmark dataset in the 2022 Pakistan flood to assess various flood prediction methods. Finally, we validate the model in three dimensions - flood inundation range, depth, and transferability of spatiotemporal downscaling. Traditional hydrodynamics and sequence-to-sequence GeoPINS exhibit exceptional agreement during high water levels, while comparative assessments with SAR-based flood depth data show that sequence-to-sequence GeoPINS outperforms traditional hydrodynamics, with smaller prediction errors.