Global operational data services for storm surge and fluvial flood forecasting

Abstract

Riverine floods and coastal inundation by storm surges are the most frequent of natural disasters, affecting millions of people across the globe every year. The forecasting of floods and storm surge at the global scale is crucial to preparing for severe events and providing early awareness where local models and warning services are lacking. Developments in modelling capabilities, data availability, and computational resources in recent years have made it possible to produce global scale flood forecasts. Operational systems currently have the capability to produce discharge and water level forecasts in the medium-range and disseminate forecasts and early warning products in real time across the globe, in support of national forecasting capabilities. Deltares currently runs two global forecasting systems: Global Flood Forecasting Information System (GLOFFIS) and Global Storm Surge Information System (GLOSSIS). These systems are run from an open experimental information and communications technology facility, IdLab, and are being used to test new ideas around interoperability, hydrological/hydrodynamical predictability, big data, and visualization. GLOFFIS and GLOSSIS produce global flood and storm surge forecasts up to four times per day, with a 10 day forecast horizon (Deltares, 2017). These forecasts can be used for early warning in areas that currently lack adequate local forecasting capabilities. In areas where such capabilities are already available, these systems can provide boundary conditions to regional or local models to further improve these. The underlying hydrodynamic and hydrological models are constantly improved and updated, to further increase their accuracy. With improvements in weather forecasting, future advances may include more seamless hydrological forecasting at the global scale alongside a move towards multi-model forecasts and grand ensemble techniques, responding to the need of developing multi-hazard early warning systems for disaster risk reduction. The global forecasts from GLOFFIS and GLOSSIS are made available through various online channels, like web applications and FTP. A subset of results has been made available free of charge in June 2017 via www.GlobalFloodForecast.com. It is foreseen that the full or higher resolution results will be provided through a service with subscription fee by the end of 2017.