Coastal inundation in the North-eastern Mediterranean coastal zone

Transcription

1 Coastal inundation in the North-eastern Mediterranean coastal zone Yannis N. Krestenitis, Ioannis Androulidakis & Yannis Kontos School of Civil Engineering Aristotle University of Thessaloniki

2 ΙΝΤΕRREG III Β - ARCHIMED CORI Project: Prevention and Management of Sea Originated Risks to the Coastal Zone WP-2: Extreme Sea Level Variability for Eastern Mediterranean

3 Coastal inundation as a result of storm surge events is a possible threat in many coastal areas. Storm surges are a result of low pressure meteorological systems and heavy winds, creating a sea level rise over the covered area of ocean. Low-elevation coastal areas and their populations are at risk during and after the appearance of a storm surge event. In these areas, any rise in sea level will have adverse impacts (coastal erosion, flooding, etc.) which depend on the time scale and the magnitude of the rise, as well as the associated human response.

4 Mediterranean Sea is not on the main storm track of the European and North Atlantic area, but storm track events originated mainly from Africa with a direction from south to north affect significantly local sea-level rise at the north Mediterranean coasts

5 Low-elevation land areas Potential inundation zones were calculated with the 90m resolution shuttle radar topography mission (SRTM) digital elevation model (DEM) Possible inundation areas in the Mediterranean for a sea level increase of 1 m above the mean sea level where determined:

6 Possible inundation areas in the North-eastern Mediterranean the northern coast of Adriatic Sea, Gulf of Manfredonia the Neretva Delta the Albanian coast the western Greek coast (Patraikos Gulf), the North Aegean coast (Alexandroupoli, Kavala & Thessaloniki areas) the Seyhan delta

7 Storm surges and storm tracks The sea level rise due to storm surge events is examined for the period , using: sea level atmospheric pressure (SLP) data [Soukissian et al., 2007] on a 1/10 o x1/10 o MED grid, sea level height (SLH) data from gauge stations around the Mediterranean, (Med-GLOSS program and the European Sea-level Service).

8 Med-GLOSS program, the European Sea-level Service and the Greek Hydrographic Service SLH timeseries and max/min values

9 Additional sea-level data were collected by using satellite data French space agency (Aviso/Altimetry project) ftp://ftp.cls.fr/pub/oceano/aviso

10 Computation and Plotting of Storm Tracks Storm Tracks identified by following low pressure centres on synoptic charts and plotting their trajectories on maps (Serreze, 1995) NASA automated cyclone detection and cyclone tracking algorithm The 3-hourly Sea Level Pressure (SLP) data 12-hourly SLP (POSEIDON weather forecasting system) Rules applied: Two successive SLP minima must be in a distance 1440 km (cyclone max speed = 120 km/hr) Storms must last at least 36 hours (three12-hr segments) Two segments on the same track must not define an angle < 85

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12 Storm-track calculation

13 storm tracks direction & magnitude 2001 Average SLP during storm track Min SLP during storm track

14 storm tracks directions & magnitude ( )

15 12hr max SLH (m) 12hr max SLH (m) 12hr mean SLP (hpa) 12hr mean SLP (hpa) Chios 2004 Alexandroupolis hr mean SLP - Time Chios hr mean SLP - Time Alexandroupoli Time (days) Time (days) hr max SLH - Time Chios Time (days) hr max SLH - Time Alexandroupoli Time (days)

16 12hr max SLH (m) 12hr max SLH (m) Chios hr max SLH - 12hr mean SLP Chios 2004 (r=-0.62) Alexandroupolis hr mean SLP (hpa) 12hr mean SLP - 12hr max SLH Alexandroupoli hr mean SLP (hpa)

17 SLP-SLH correlations for the period of Station Ancona (Italy) Antalya (Turkey) Alexandroupolis (Greece) Barcelona (Spain) Catania (Italy) Chios (Greece) Dubrovnik (Croatia) Genova (Italy) Lefkas (Greece) Naples (Italy) Otranto (Italy) Rovinj (Croatia) Split (Croatia) Trieste (Italy) Zadar (Croatia)

18 Storm surge model A 2-dimensional hydrodynamic model Grid resolution 1/10 o x 1/10 o Forcing: wind data, atmospheric pressure and wave data Boundary conditions: Tidal input imposed in the Gibraltar

19 Alexandroupolis In situ measurements and model results In situ measurements Model results Dubrovnik

20 Sea level Alteration February 5, 2003 Direction: W-E The coastal areas affected by this event are especially in the central Adriatic and the south Aegean 10 x(m) y(m) SLP(hPa) _PM _AM Model output _PM _AM _PM _AM days _PM _AM

21 max Sea Level Rises and % frequencies Coastal area Max Sea Level Rise Sea Level Rise ΔH>+0.30m Sea Level Rise ΔH>+0.60m Rovinj (HR) Dubrovnik (HR) Alexandroupoli (GR) Lefkas (GR) Chios (GR) Antalya II (TR) Split (HR) Trieste (IT) Catania (IT) Ancona (IT) Otranto (IT) Kavala (GR) Herakleio (GR) Thessaloniki (GR) Zadar (HR) *Venice (IT) *Albanian coasts *Adana (TR) *Alexandroupoli (GR) *Malliakos Gulf (GR) *Patras (GR) *Bari (IT)

22 max SLH (m) % Frequency of SLH>20cm max Sea Level Rises and % frequencies % Frequency of SLH>20cm in various areas of Eastern Mediterranean for years (model hindcasting) max SLH in various areas of Eastern Mediterranean years (model hindcasting) for Rovinj (HR) Dubrovnik (HR) Alexandroupoli (GR) Lefkas (GR) Chios (GR) Antalya II (TR) Split (HR) Trieste (IT) Catania (IT) Naples (IT) Ancona (IT) Otranto (IT) Kavala (GR) Herakleio (GR) Thessaloniki (GR) Zadar (HR) *Alexandria (EG) *Venice (IT) *Albanian coasts *Adana (TR) *Alexandroupoli (GR) *Malliakos Gulf (GR) *Patras (GR) *Banghazi (LY) *Bari (IT) *Tripolis (LY) 0 1,40 1,20 1,00 0,80 0,60 0,40 0,20 0,00 Rovinj (HR) Dubrovnik (HR) Alexandroupoli (GR) Lefkas (GR) Chios (GR) Antalya II (TR) Split (HR) Trieste (IT) Catania (IT) Naples (IT) Ancona (IT) Otranto (IT) Herakleio (GR) Thessaloniki (GR) Zadar (HR) Kavala (GR) *Alexandria (EG) *Venice (IT) *Albanian coasts *Adana (TR) *Alexandroupoli (GR) *Malliakos Gulf (GR) *Patras (GR) *Banghazi (LY) *Bari (IT) *Tripolis (LY)

23 Google-earth maps & inundation data

24 Conclusions - Proposals Hindcasting storm surge events and detecting previous inundation cases can offer to stakeholders a better view of possible changes and corrections that need to be done in already developed risky coastal areas. The combination of atmospheric forecasting models with a storm surge hydrodynamic model can estimate the future sea level rise events and the inundation risk in the low elevation coastal areas. The couple forecasting models (atmospheric + wave + storm-surge) could be the main tool for a warning systems of coastal flooding. These system can improve authorities preparedness and help coastal human society to obtain proper measurements in cases of an extreme meteorological incidents. The couple forecasting models (atmospheric + wave+ storm-surge) could help for the adoption of the European Directive 2007/60/ΕC

25 European Directive 2007/60/ΕC (23/10/2007) On the assessment and management of flood risks flood means the temporary covering by water of land not normally covered by water. This shall include floods from rivers, mountain torrents, Mediterranean ephemeral water courses, and floods from the sea in coastal areas, Member States will by 2011 undertake a preliminary flood risk assessment of their river basins and associated coastal zones, to identify areas where potential significant flood risk exists. Where real risks of flood damage exist, they must by 2013 develop flood hazard maps and flood risk maps for such areas. By 2015 flood risk management plans must be drawn up for these zones.

26 Thank you for your attention