Hindcasts and Forecasts of Coastal Flooding Triggers

D4.1 Report on the calibration and validation of hindcasts and forecasts of TWL. – Download it here from Zenodo.*
In ECFAS, forecasts of total water levels (TWL) at the coast can trigger the rapid mapping of coastal floods of the ECFAS awareness system when they exceed pre-identified local thresholds of total water levels. To define these local thresholds of TWL along the European coastline, a joint analysis of a hindcast of past TWL (extreme value analysis) and of past coastal flooding events is needed. Forecasts of TWL are thus the first building block of the ECFAS awareness system, and condition the activation of the awareness system.
The present document reports on the production, calibration and validation of the numerical-model-based forecasts and hindcasts of TWL at the coast that are underpinning the warning component of the ECFAS proof-of-concept. The skill assessment of the forecasts and hindcasts of TWL will inform on the expected skills of the ECFAS proof-of-concept, as they condition the activation of the ECFAS proof-of-concept.
D4.2 Report on the inter-comparison between CMEMS and ANYEU-SSL modelling systems. – Download it here from Zenodo.*
The present work aimed to identify the required level of complexity in numerical models for a more accurate representation of coastal water-levels used as marine forcing in coastal flood warning applications such as ECFAS. The level of complexity is evaluated in terms of added physical processes as well as by analyzing different configurations of the models. To this aim, the model systems used in ECFAS to produce hindcasts -ANYEU-SSL (2D) for the European region – and forecasts -CMEMS (3D) for the northeastern Atlantic region (Iberia Biscay Ireland, IBI)- were tested (ECFAS D4.1 – Report on the calibration and validation of hindcasts and forecasts of TWL). Two physical processes were considered: the surge and tide non-linear interaction and the wave and surge non-linear interaction. The models show moderate to strong sensitivity to both processes, in particular during extreme events, highlighting the potential importance of these processes for accurate numerical predictions of extreme coastal total water-levels. The derived limitations and future recommendations are presented, in the context of the possible future roadmap of integration of the ECFAS system into the Copernicus Emergency Management Service.
D4.3 Report on the identification of local thresholds of TWL for triggering coastal flooding. – Download it here from Zenodo.*
The ECFAS Deliverable 4.3 – Report on the identification of local threshold of TWL for triggering coastal flooding aims to describe the methodology developed to identify local thresholds that will trigger the coastal flood mapping activity. To this end, it was necessary to identify both a total water level triggering threshold, used as a local reference to trigger the system in case of forecasted TWL exceedance, and a duration threshold, used to set the storm duration. In order to compute both thresholds, an Extreme Value Analysis (EVA) and a Duration Analysis (DA) were performed on the ECFAS combined hindcast. As the local TWL thresholds (triggering and duration) were identified using the ECFAS combined hindcast, and the system will instead be operative with the input of CMEMS forecast, a methodology was developed to establish a correction to be applied before integrating the thresholds into the warning system. The document also describes some limitations and possible future improvements of the employed methodology.
The Deliverable 4.3 – Report on the identification of local thresholds of TWL for triggering coastal flooding is accompanied by an accessory data file. This file, named “ThresholdsFile.csv”, contains the values of the triggering and duration thresholds for all the ECFAS combined hindcast of TWL points and their coordinates.

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