JRC Sea Level Database

The Joint Research Centre (JRC) of the European Commission has developed a storm surge system for the Tropical Cyclones included in the Global Disasters Alert and Coordination System (GDACS) and the Storm Surge Calculation System (SSCS) for the storm surge events in Europe. Every day the results of these calculation systems are compared with the measurements included in the JRC Sea Level Database. This database includes the sea level measurements, theoretical sea levels tides and storm surge for more than 1000 stations around the world and is wildly used in storm surge and tsunami activities. Currently, the alert levels in the JRC storm surge systems are based only on the maximum storm surge heights and don’t include the effect of the tides. This effect is very important, because the increase of the water level is extremely damaging when the storm surge coincides with a period of high tide. In this analysis, the JRC Sea Level Database is used to show the importance of the tides in the JRC storm surge alert systems (GDACS and SSCS).JRC.E.1-Disaster Risk Managemen

Continuous Harmonics Analysis of Sea Level Measurements: Description of a new method to determine sea level measurement tidal component

Removing the tidal component from sea level measurement in the case of Tropical Cyclones or Tsunami is very important to distinguish the tide contribution from the one of the Natural events. The report describes the methodology used by JRC in the de-tiding process and that is used for thousands of sea level measurement signals collected in the JRC Sea Level Database.JRC.E.1-Disaster Risk Managemen

JRC storm surge system: new developments

JRC has developed the first storm surge calculation system for the Tropical Cyclones (TCs) included in the Global Disasters Alert and Coordination System (GDACS) in 2011. The TCs are not the only weather system that can generate a storm surge event, therefore a new Storm Surge Calculation System (SSCS) has been developed in 2013, to simulate the storm surge also in Europe. JRC has recently developed and implemented a new storm surge system, using a new hydrodynamic code and new atmospheric forecasts, creating several new SSCS bulletins and TCs GDACS web pages. This report describes the new procedures developed.JRC.E.1-Disaster Risk Managemen

JRC storm surge system for Europe: JRC SSCS bulletins and the new GDACS system

The storm surge is an abnormal rise of water above the astronomical tides, generated by strong winds and a drop in the atmospheric pressure, due to the passage of a Tropical Cyclone (TC) or an intense low pressure system in general. The JRC has developed the first storm surge calculation system for the TCs in 2011, including the results in the Global Disasters Alert and Coordination System (GDACS). The TCs are not the only weather system that can generate a storm surge event, therefore the JRC has developed a new Storm Surge Calculation System (SSCS) in 2013, to simulate the storm surge also in Europe. The SSCS system has been established at the JRC in the frame of GDACS and it is intended as a series of procedures that use meteorological forecasts forcing conditions produced by several meteorological centers to obtain the expected sea level rise along the coasts. Every day several SSCS bulletins are created for different areas of Europe. The JRC is currently implementing this system also in GDACS. This report describes the procedures of this new storm surge system developed by the JRC and the SSCS bulletins produced every day, as well as the implementation of this system in GDACS.JRC.E.1-Disaster Risk Managemen

Statistical Validation and Skill Assessment of Hyflux2 Model

The Joint Research Center (JRC) has developed extensive experience in tsunami early warning systems, using the JRC-SWAN finite difference code for wave propagation simulation and the JRC finite-volume HyFlux2 code for wave propagation and inundation modelling over the last years. Since 2011, NWP (Numerical Weather Prediction) atmospheric forcing terms have been included in the HyFlux2 code for simulating storm surge events. In the current work, the skill assessment of Hylfux2 is performed. A wide range of verification metrics has been utilised for both Hyflux2 model data sets namely NOF (raw forecasts with no adjustment) and YOF (post forecasts by applying an optimal type of offset). Investigating over typical metrics as bias, root mean square error (RMSE) and centred root mean square differences (CRMSD), inter-comparisons were possible versus another integrated storm surge forecast system namely KASSANDRA (KASS) of ISMAR-CNR. Referring to the ability of reproducing the variability of observations, inter-comparing over 10 common stations revealed that Hyflux2 YOF configuration although in the right direction, is not reaching the quality of KASS system for T+24-hour horizon. Hyflux2 normalised standard deviation manages to reach the 0.81 value compared to 0.97 value of KASS (with perfect score: 1.0). On the other hand, the most important message seems to be the one coming from the inter-comparison between CRMSD scores. Hylfux2 YOF forecasts appear to have a comparable CRMSD score (6.42 cm) to the score coming from KASS system (5.86 cm) for T+24 hours. Furthermore, there are stations (like Civitavecchia, Genova, Napoli and Palermo) over which Hyflux2 YOF forecasts score considerably better than KASS system, whereas the rest of YOF forecasts appear to have a lower (but still of high quality) correlation coefficient (0.80) score compared to the one coming from KASS system (0.89 cm) for T+24 hours. Another important area that special type of metrics was used (such as accuracy, frequency bias, hit rate, false alarm ratio, probability of false detection, success ratio, threat score, equitable threat score, true skill statistics, odds ratio and odds ratio skill score) has been the ability of Hyflux2 to provide useful (warning) forecast guidance in cases of high-intensity storm surge events. The selection of an optimal (95% percentile) threshold was made being high enough to be considered as extreme but also capable of providing enough cases for robust statistics. The main outcome of such an approach has revealed that 72% (T+72 hours) to 79% (T+12 hours) of all Hyflux2 forecasts were correct over central Mediterranean (CMEDI) for both NOF and YOF forecasts. The corresponding values for west Mediterranean (WMEDI) were reaching even higher values (80 - 81% to 88%) with similar skill values for both NOF and YOF configurations, but it should be stressed out that these results have considered a large number of correct negatives (referring to non-extremes events). Focussing over high-intensity events (that have been observed) Hylfux2 appears to have considerable forecasting limitations being able to capture only the 23% (T+72) to 34% (T+12) of events while missing more than 70% of the high-intensity events at T+48 hours. Such forecasting limitations become obvious during the in-depth analysis over two case study extreme events taken place over Ravenna (6 February 2015) and Venice (29 February 2016). The capabilities of both NOF & YOF forecasts based on ECMWF relatively low-resolution forcing terms to provide useful guidance in Ravenna case found to be limited even if both NOF & YOF managed to provide a relatively useful early warning for the extreme case of Venice. It appears that both NOF & YOF configurations (based on ECMWF forcing terms) have certain limitations to provide the best possible setup for detecting and simulating such high-impact events. On the other hand, HYflux2 YOF forecasts based on various COSMO model high-resolution forcing terms seem to do quite much better in capturing both events and providing useful (early) warning to the user. It seems that for such high-impact events higher-resolution forcing terms are necessary to correctly resolve the full extent and magnitude of the event. This higher resolution feature is most probably the reason why Hyflux2 based on COSMO model (run operationally by the Italian Air Force Weather Meteorological Service) high-resolution forcing terms provides much more useful guidance in cases of extreme events.JRC.E.1-Disaster Risk Managemen

Tropical Cyclones and Storm Surge Modelling Activities

The Global Disasters Alert and Coordination System (GDACS) automatically invokes ad hoc numerical models to analyse the level of the hazard of natural disasters like earthquakes, tsunamis, tropical cyclones, floods and volcanoes. The Tropical Cyclones (TCs) are among the most damaging events, due to strong winds, heavy rains and storm surge. In order to estimate the area and the population affected, all three types of the above physical impacts must be taken into account. GDACS includes all these dangerous effects, using various sources of data. The JRC set up an automatic routine that includes the TC information provided by the Joint Typhoon Warning Center (JTWC) and the National Oceanic and Atmospheric Administration (NOAA) into a single database, covering all TCs basins. This information is used in GDACS for the wind impact and as input for the JRC storm surge system. Recently the global numerical models and other TC models have notably improved their resolutions, therefore one of the first aim of this work is the assessment and implementation of new data sources for the wind, storm surge and rainfall impacts in GDACS. Moreover the TC modelling workflow has been revised in order to provide redundancy, transparency and efficiency while addressing issues of accuracy and incorporation of additional physical processes. The status of development is presented along with the outline of future steps.JRC.E.1-Disaster Risk Managemen

Tropical Cyclone ENAWO - Post-Event Report

Tropical Cyclones (TCs) are among the most damaging events. They affect the population with three dangerous effects: strong wind, heavy rain and storm surge. JRC has developed a system used in Global Disaster Alert and Coordination System (GDACS) that includes the analysis of all these effects for every TC occurring worldwide to assess the overall impact. This document is the first POST-EVENT Report, which is a new type of report produced by the JRC after a major event aimed to report the real status of the impact that occurred, based on media reports, onsite analyses, and satellite images. The event analysed in this report is the intense TC ENAWO, that made landfall in north-eastern Madagascar on 7 March 2017, killing more than 80 people and causing extensive damage, especially in Sava and Analanjirofo regions. Authorities issued a "declaration of national emergency" and formally requested international assistance on 14 March. GDACS issued the first RED alert (for high winds) in Madagascar on 3 March. The Emergency Response Coordination Centre (ERCC) of DG ECHO activated ARISTOTLE on 5 March and the Copernicus Emergency Management Service (EMS) on 7 March. The responses of the alert and information systems are analysed and the results are compared with the damage reported by national authorities and satellite images analysis. In order to improve the current early warning system and impact estimations, JRC is implementing a new method to evaluate the areas potentially most affected by a TC, using new datasets and classifications. The results are also included in the report.JRC.E.1-Disaster Risk Managemen

Tropical Cyclone ISAAC. USA, August 2012

Tropical Cyclone ISAAC, after causing damage and deaths in Haiti, moved towards the coast of SE Louisiana (USA), where it made two landfalls. After the second landfall, it started moving inland in SE Louisiana, passing W of New Orleans on Aug 29 afternoon/evening (UTC), weakening into a tropical storm, then late on Aug 30 became a tropical depression. Tropical Cyclone ISAAC affected the southern parts of Louisiana, Mississippi and Alabama with heavy rainfall, strong winds and storm surge, causing flooding, power outages, damage to property and, according to media report, killing at least 7 people. Most of this damage has been caused by heavy rains and storm surge. The Joint Research Centre (JRC) followed the event through the information automatically collected and analysed in the Global Disasters Alerts and Coordination System (GDACS). GDACS classification, for TC ISAAC in the USA, was: Green for the wind impact, Orange for rain impact and Red for storm surge impact. On 27 August 2012, 2 days before the landfall, the JRC HyFlux2 storm surge model indicated a possible storm surge in the order of 2.5-3.5m for Aug 29 morning (UTC) in the coastal area E-SE of New Orleans, Louisiana Online observations and NOAA reports confirmed the forecasts. This report analyses and discusses the GDACS automatic impact assessments and compares the JRC HyFlux2 deterministic storm surge forecasts with the probabilistic forecasts provided by NOAA.JRC.G.2-Global security and crisis managemen

Tropical Cyclone GIOVANNA. Madagascar, February 2012

JRC has developed GDACS, an early warning system created to alert the humanitarian community about potential disasters which are under development. Tropical cyclones are some of the most damaging events, affecting the coastal population with three dangerous effects: strong wind, heavy rain and storm surge. GDACS includes the analysis of the first and the second effects, and recently also the third effect (storm surge) has been implemented. An impact assessment for all the three alerts are presented in the report. Wind alert level estimated by GDACS was Red, due to the high wind and the high vulnerability of the affected country. The wind impact assessment by BNGRC has confirmed that most of the damage due to Giovanna was caused by strong winds. The region most affected has been Antisanana. The rain impact alert level in GDACS is based on the estimation of the total accumulation of rainfall on land using NOAA eTRaP data. The applicability of the data was considered fine for alert levels at regional level, but not at local level due to spatial uncertainty. The storm surge GDACS alert level is based on the calculations of the JRC code HyFlux2. The accuracy of the estimated storm surge height could not be established because the available tide gauge was malfunctioning. We compared our results with two UNOSAT/UNITAR impact assessment maps of two damaged cities (Brickaville and Vatomadry). These maps gave a clear indication of building damages, as a result of strong winds and storm surge while the JRC calculations showed a storm surge in the order of 1 m. Overall, the GDACS models performed well. Alert levels for all hazard components were consistent with the observed impact. The location and timing of the information could accurately identify the affected provinces. GDACS information is appropriate for near real-time strategic decision making.JRC.G.2-Global security and crisis managemen

TROPICAL CYCLONES in GDACS Data sources

The Global Disaster Alert and Coordination System (GDACS) provides alerts and preliminary impact estimations of the natural disasters around the world, like earthquakes, tsunami, tropical cyclones and floods. The Tropical Cyclones (TCs) are among the most damaging events. They affect the population with three dangerous effects: strong wind, heavy rain and storm surge. GDACS has developed a system that includes the analysis of all these effects for every TC occurring worldwide, using several different data sources. This report describes these data sources and the tools developed by the JRC to include the TC information in GDACS, as well as the new products that could be used to improve the current systemJRC.E.1 - Disaster Risk Managemen