Can we manage the unexpected? Constructing plausible storm tides with high impact potential and consequences for coastal protection and disaster risk management.
Abstract
Planning and design of coastal protection requires information about the probabilities of very severe storm tides and about the possible changes that may occur in the course of anthropogenic climate change. So far this information is mostly provided in the form of high percentiles obtained from frequency distributions, or return levels. More detailed information and assessment of events that are highly unlikely but which are potentially linked with extreme consequences is so far mostly unavailable.
The EXTREMENESS group has taken an approach to address these issues for parts of the German North Sea coast. In collaboration with a group of stakeholders from authorities, disaster risk management, industry and other interest groups those elements of severe storm tides were identified that may create risk for strong impacts and cascading effects. Simple measures such as extreme surges or total water levels were used, but also more complicated metrics and narrative scenarios were developed and considered. Subsequently a huge data base consisting of historical data, global and regional atmospheric and met-ocean reanalyzes and climate change projections was scanned for potential high impact events. In total data comprised about 13,000 data years. Based on the metrics and scenarios developed, a set of extreme cases was selected. For these cases, a systematic assessment was made on mechanisms that may lead to further amplification; that is, on whether or not more severe realizations are possible within physically plausible limits. Factors such as future sea level rise, increased river runoff or the fact that the onset of strong winds is independent of the tide, were analyzed using high-resolution atmospheric and tide-surge models. For the most severe cases, failures and potential consequences according to the scenarios were simulated. Capacities to deal with potentially cascading effects were analyzed together with stakeholders in a simplified simulation exercise.- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMOS31D1759W
- Keywords:
-
- 1641 Sea level change;
- GLOBAL CHANGE;
- 4217 Coastal processes;
- OCEANOGRAPHY: GENERAL;
- 4262 Ocean observing systems;
- OCEANOGRAPHY: GENERAL;
- 4556 Sea level: variations and mean;
- OCEANOGRAPHY: PHYSICAL