Periodic Reporting for period 2 - SpaDeRisks (Spatial dependencies of storm surges and global risk assessment.)
Période du rapport: 2024-01-15 au 2025-01-14
Coastal flooding caused by extreme storm surges, is a growing threat to communities worldwide. These events can cause widespread damage, disrupt lives, and strain economies. A critical but often overlooked aspect of coastal flooding is the spatial dependency of these events—meaning that when one area experiences flooding, nearby or even distant regions may also be affected simultaneously. Traditional flood risk assessments typically assume that flooding events occur independently, which can lead to underestimating the true risk and potential damage.
Coastal flooding is one of the most devastating natural hazards, affecting millions of people and causing billions of euros in damage annually. With climate change accelerating sea-level rise and potentially altering storm patterns, the frequency and severity of coastal flooding are expected to increase. By improving our understanding of how flooding events are spatially connected, we can better predict and prepare for large-scale flooding events. This knowledge is crucial for governments, insurance companies, and coastal planners to design more resilient infrastructure, develop effective emergency response plans, and protect vulnerable communities.
The SpaDeRisks project aimed to address these challenges by:
1. Investigating the spatial dependencies of extreme sea levels and storm surges on a global scale, including how these dependencies change over time due to seasonal and decadal climate variability.
2. Developing a new framework to incorporate spatial dependencies into coastal flood risk assessments, providing more accurate estimates of flooding risks and economic losses.
3. Assessing future coastal flood risks under different climate change scenarios, including rising sea levels and potential changes in storm patterns, and accounting for the spatial dependencies.
Coastal flooding is one of the most devastating natural hazards, affecting millions of people and causing billions of euros in damage annually. With climate change accelerating sea-level rise and potentially altering storm patterns, the frequency and severity of coastal flooding are expected to increase. By improving our understanding of how flooding events are spatially connected, we can better predict and prepare for large-scale flooding events. This knowledge is crucial for governments, insurance companies, and coastal planners to design more resilient infrastructure, develop effective emergency response plans, and protect vulnerable communities.
The SpaDeRisks project aimed to address these challenges by:
1. Investigating the spatial dependencies of extreme sea levels and storm surges on a global scale, including how these dependencies change over time due to seasonal and decadal climate variability.
2. Developing a new framework to incorporate spatial dependencies into coastal flood risk assessments, providing more accurate estimates of flooding risks and economic losses.
3. Assessing future coastal flood risks under different climate change scenarios, including rising sea levels and potential changes in storm patterns, and accounting for the spatial dependencies.
The first phase of the project investigated the heart of the problem: understanding how extreme sea levels and storm surges are connected across space and time. Using advanced statistical methods like K-Means clustering and copula analysis, we mapped the spatial footprints of these events on a global scale. We discovered recurring patterns, particularly in regions like the Gulf of Mexico, where seasonal and decadal changes in spatial dependencies were pronounced. By identifying the weather patterns—such as atmospheric pressure and wind dynamics—driving these changes, the team gained deeper insights into the physical processes behind coastal flooding.
We identified the years when the flooding risk is higher due to the interaction between the storm surges and astronomical tides using statistical models and sea level observations from tide gauges. The results allowed us to also project in the future when the next peak in flooding risk will occur and where along the global coasts.
In addition to the spatial clusters, we assess the temporal clustering of storm surges. This approach revealed that some coastal areas experience clusters of storm surges in quick succession, leaving little time for recovery between events and significantly increasing flood risk.
With a clearer understanding of spatial dependencies, the team shifted focus to developing a new framework for coastal flood risk assessment. We created a synthetic dataset of spatially dependent ESWLs, which provided a more realistic basis for modeling flood risks. This dataset was complemented by the development of MatFlood, an efficient and user-friendly flood mapping tool. MatFlood allowed the team to simulate flood depth and extent, accounting for the spatial variability of coastal water levels.
The team then applied this framework to calculate present-day flood risk metrics, such as annual damage losses. By comparing these metrics with conventional approaches—which often assume complete independence or dependence between events—they demonstrated that neglecting spatial dependencies can lead to significant underestimations of flood risk. This work was further enriched by a study on compound flooding drivers along the northeastern US coasts, which explored how coastal flooding interacts with other hazards like river discharge and precipitation. The findings underscored the importance of considering multiple hazards in flood risk assessments.
The final phase of the project looked to the future, evaluating how coastal flood risks might evolve under different climate change scenarios. Using the MatFlood model, I simulated flood maps for future mean sea level conditions. A key case study focused on the Baltic coast of Germany, where collaboration with Kiel University enabled the integration of spatial dependencies into economic damage assessments.
Within the project, we delivered: 9 peer-reviewed papers, 4 conference contributions, a website containing flooding maps under future mean sea level conditions and extreme events in the Gulf of Mexico, a model to efficiently simulate coastal flooding taking into account the spatial varying coastal sea level, and a dataset containing spatial dependent storm surge events that can be used in flooding risk analysis.
These advancements provide valuable insights for policymakers, insurers, and coastal communities, helping them better prepare for and mitigate the impacts of coastal flooding in a changing climate. The project’s outcomes contribute to global efforts to enhance coastal resilience and reduce the societal and economic impacts of extreme sea level events.
No website has been developed for the project yet.
We identified the years when the flooding risk is higher due to the interaction between the storm surges and astronomical tides using statistical models and sea level observations from tide gauges. The results allowed us to also project in the future when the next peak in flooding risk will occur and where along the global coasts.
In addition to the spatial clusters, we assess the temporal clustering of storm surges. This approach revealed that some coastal areas experience clusters of storm surges in quick succession, leaving little time for recovery between events and significantly increasing flood risk.
With a clearer understanding of spatial dependencies, the team shifted focus to developing a new framework for coastal flood risk assessment. We created a synthetic dataset of spatially dependent ESWLs, which provided a more realistic basis for modeling flood risks. This dataset was complemented by the development of MatFlood, an efficient and user-friendly flood mapping tool. MatFlood allowed the team to simulate flood depth and extent, accounting for the spatial variability of coastal water levels.
The team then applied this framework to calculate present-day flood risk metrics, such as annual damage losses. By comparing these metrics with conventional approaches—which often assume complete independence or dependence between events—they demonstrated that neglecting spatial dependencies can lead to significant underestimations of flood risk. This work was further enriched by a study on compound flooding drivers along the northeastern US coasts, which explored how coastal flooding interacts with other hazards like river discharge and precipitation. The findings underscored the importance of considering multiple hazards in flood risk assessments.
The final phase of the project looked to the future, evaluating how coastal flood risks might evolve under different climate change scenarios. Using the MatFlood model, I simulated flood maps for future mean sea level conditions. A key case study focused on the Baltic coast of Germany, where collaboration with Kiel University enabled the integration of spatial dependencies into economic damage assessments.
Within the project, we delivered: 9 peer-reviewed papers, 4 conference contributions, a website containing flooding maps under future mean sea level conditions and extreme events in the Gulf of Mexico, a model to efficiently simulate coastal flooding taking into account the spatial varying coastal sea level, and a dataset containing spatial dependent storm surge events that can be used in flooding risk analysis.
These advancements provide valuable insights for policymakers, insurers, and coastal communities, helping them better prepare for and mitigate the impacts of coastal flooding in a changing climate. The project’s outcomes contribute to global efforts to enhance coastal resilience and reduce the societal and economic impacts of extreme sea level events.
No website has been developed for the project yet.
The SpaDeRisks project has pushed the boundaries of coastal flood risk assessment, tackling a critical gap in our understanding: the spatial dependencies of extreme sea levels and storm surges. Traditional methods often assume flooding events occur independently, but SpaDeRisks revealed that these events are often connected across space and time. By mapping these connections and analyzing how they change seasonally and decadally, the project has provided a more accurate and dynamic picture of flood risks. We identify how, where, and when, the risk of flooding by a 100-year return event will increase along the global coasts.
We developed innovative tools, including MatFlood, a flood mapping model, and datasets such as the synthetic dataset of extreme sea levels, both freely available for anyone to assess coastal flooding risks. For governments and insurers, the project’s findings enable more accurate risk assessments, saving costs and improving disaster preparedness. For coastal communities, it offers tools and knowledge to build resilience against flooding, protecting lives and livelihoods.
Through SpaDeRisks, we initiated additional studies investigating other aspects of coastal flooding risk, such as the temporal clustering of storms and the compounding effects of multiple hazard events. These research efforts, along with new collaborations, are ongoing and will continue to explore the research avenues opened by SpaDeRisks, ensuring its impact extends well beyond the project’s timeline.
Outreach activities, such as those conducted at the Orlando Science Center, were designed to engage children of different age groups, teaching them about the importance of coastal protection and inspiring the next generation to tackle the challenges of coastal flooding.
We developed innovative tools, including MatFlood, a flood mapping model, and datasets such as the synthetic dataset of extreme sea levels, both freely available for anyone to assess coastal flooding risks. For governments and insurers, the project’s findings enable more accurate risk assessments, saving costs and improving disaster preparedness. For coastal communities, it offers tools and knowledge to build resilience against flooding, protecting lives and livelihoods.
Through SpaDeRisks, we initiated additional studies investigating other aspects of coastal flooding risk, such as the temporal clustering of storms and the compounding effects of multiple hazard events. These research efforts, along with new collaborations, are ongoing and will continue to explore the research avenues opened by SpaDeRisks, ensuring its impact extends well beyond the project’s timeline.
Outreach activities, such as those conducted at the Orlando Science Center, were designed to engage children of different age groups, teaching them about the importance of coastal protection and inspiring the next generation to tackle the challenges of coastal flooding.