Mapping the return periods of extreme sea levels: Allowing for short sea level records, seasonality, and climate change

Ports constitute a significant influence in the economic activity in coastal areas through operations and infrastructures to facilitate land and maritime transport of cargo. Ports are located in a multi-dimensional environment facing ocean and river hazards. Higher warming scenarios indicate Europe’s ports will be exposed to higher risk due to the increase in extreme sea levels (ESL), a combination of the mean sea level, tide, and storm surge. Located on the west Iberia Peninsula, the Aveiro Port is located in a coastal lagoon exposed to ocean and river flows, contributing to higher flood risk. This study aims to assess the flood extent for Aveiro Port for historical (1979–2005), near future (2026–2045), and far future (2081–2099) periods scenarios considering different return periods (10, 25, and 100-year) for the flood drivers, through numerical simulations of the ESL, wave regime, and riverine flows simultaneously. Spatial maps considering the flood extent and calculated area show that most of the port infrastructures' resilience to flooding is found under the historical period, with some marginal floods. Under climate change impacts, the port flood extent gradually increases for higher return periods, where most of the terminals are at high risk of being flooded for the far-future period, whose contribution is primarily due to mean sea-level rise and storm surges.

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Supporting European coastal sectors to adapt to changes in extreme sea levels with climate change

10.5194/egusphere-egu2020-19471 ◽

2020 ◽

Author(s):

Sanne Muis ◽

Maialen Irazoqui Apecechea ◽

Job Dullaart ◽

Joao de Lima Rego ◽

Kristine S. Madsen ◽

...

Keyword(s):

Climate Change ◽

Sea Level ◽

Storm Surges ◽

Climate Impact ◽

Climate Impacts ◽

Water Levels ◽

Climate Data ◽

Local Climate ◽

Sea Levels ◽

Extreme Sea Levels

Climate change will lead to increases in the flood risk in low-lying coastal areas. Understanding the magnitude and impact of such changes is vital to design adaptive strategies and create awareness. In&#160; the&#160; context&#160; of&#160; the&#160; CoDEC&#160; project&#160; (Coastal&#160; Dataset&#160; for&#160; Evaluation&#160; of&#160; Climate&#160; impact),&#160; we&#160; developed a consistent European dataset of extreme sea levels, including climatic changes from 1979 to 2100. To simulate extreme sea levels, we apply the Global Tide and Surge Model v3.0 (GTSMv3.0), a 2D hydrodynamic model with global coverage. GTSM has a coastal resolution of 2.5 km globally and 1.25 km in Europe, and incorporates dynamic interactions between sea-level&#160; rise,&#160; tides&#160; and&#160; storm surges. Validation of the dataset shows a good performance with a mean bias of 0-.04 m for the 1 in 10-year water levels. When analyzing changes in extreme sea levels for the future climate scenarios, it is projected that by the end of the century the 1 in 10-year water levels are likely to increase up to 0.5 m. This change is largely driven by the increase in mean sea levels, although locally changes in storms surge and interaction with tides can amplify the impacts of sea-level rise with changes up to 0.2 m in the 1 in 10-year water level.The CoDEC dataset will be made accessible through a web portal on Copernicus Climate Data Store (C3S). The dataset includes a set of Climate Impact Indicators (CII&#8217;s) and new tools designed to evaluate the impacts of climate change on different sectors and industries. This data service will support European coastal sectors to adapt to changes in sea levels associated with climate change. In this presentation we will also demonstrate how the C3S coastal service can be used to enhance the understanding of local climate impacts.

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Modelling the increased frequency of extreme sea levels in the Ganges–Brahmaputra–Meghna delta due to sea level rise and other effects of climate change

Environmental Science Processes & Impacts ◽

10.1039/c4em00683f ◽

2015 ◽

Vol 17 (7) ◽

pp. 1311-1322 ◽

Cited By ~ 33

Author(s):

S. Kay ◽

J. Caesar ◽

J. Wolf ◽

L. Bricheno ◽

R. J. Nicholls ◽

...

Keyword(s):

Climate Change ◽

Sea Level Rise ◽

Sea Level ◽

21St Century ◽

Bay Of Bengal ◽

Hydrodynamic Model ◽

Sea Levels ◽

Extreme Sea Levels ◽

The Ganges

A hydrodynamic model of the Bay of Bengal has been used to explore increasing frequency of extreme sea levels in the Ganges–Brahmaputra–Meghna delta over the 21st century.

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Assessment and comparison of extreme sea levels and waves during the 2013/14 storm season in two UK coastal regions

Natural Hazards and Earth System Science ◽

10.5194/nhess-15-2209-2015 ◽

2015 ◽

Vol 15 (10) ◽

pp. 2209-2225 ◽

Cited By ~ 22

Author(s):

M. P. Wadey ◽

J. M. Brown ◽

I. D. Haigh ◽

T. Dolphin ◽

P. Wisse

Keyword(s):

Sea Level Rise ◽

Sea Level ◽

Data Sets ◽

Return Periods ◽

Data Set ◽

Sea Levels ◽

Extreme Sea Levels ◽

Study Sites

Abstract. The extreme sea levels and waves experienced around the UK's coast during the 2013/14 winter caused extensive coastal flooding and damage. Coastal managers seek to place such extremes in relation to the anticipated standards of flood protection, and the long-term recovery of the natural system. In this context, return periods are often used as a form of guidance. This paper provides these levels for the winter storms, and discusses their application to the given data sets for two UK case study sites: Sefton, northwest England, and Suffolk, east England. Tide gauge records and wave buoy data were used to compare the 2013/14 storms with return periods from a national data set, and also joint probabilities of sea level and wave heights were generated, incorporating the recent events. The 2013/14 high waters and waves were extreme due to the number of events, as well as the extremity of the 5 December 2013 "Xaver" storm, which had a high return period at both case study sites. The national-scale impact of this event was due to its coincidence with spring high tide at multiple locations. Given that this event is such an outlier in the joint probability analyses of these observed data sets, and that the season saw several events in close succession, coastal defences appear to have provided a good level of protection. This type of assessment could in the future be recorded alongside defence performance and upgrade. Ideally other variables (e.g. river levels at estuarine locations) would also be included, and with appropriate offsetting for local trends (e.g. mean sea-level rise) so that the storm-driven component of coastal flood events can be determined. This could allow long-term comparison of storm severity, and an assessment of how sea-level rise influences return levels over time, which is important for consideration of coastal resilience in strategic management plans.

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Assessment and comparison of extreme sea levels and waves during the 2013/2014 storm season in two UK coastal regions

Natural Hazards and Earth System Sciences Discussions ◽

10.5194/nhessd-3-2665-2015 ◽

2015 ◽

Vol 3 (4) ◽

pp. 2665-2708 ◽

Cited By ~ 4

Author(s):

M. P. Wadey ◽

J. M. Brown ◽

I. D. Haigh ◽

T. Dolphin ◽

P. Wisse

Keyword(s):

Sea Level ◽

Return Period ◽

Data Sets ◽

Return Periods ◽

National Scale ◽

Sea Levels ◽

Extreme Sea Levels ◽

Study Sites

Abstract. The extreme sea levels and waves experienced around the UK's coast during the 2013/2014 winter caused extensive coastal flooding and damage. In such circumstances, coastal managers seek to place such extremes in relation to the anticipated standards of flood protection, and the long-term recovery of the natural system. In this context, return periods are often used as a form of guidance. We therefore provide these levels for the winter storms, as well as discussing their application to the given data sets and case studies (two UK case study sites: Sefton, northwest England; and Suffolk, east England). We use tide gauge records and wave buoy data to compare the 2013/2014 storms with return periods from a national dataset, and also generate joint probabilities of sea level and waves, incorporating the recent events. The UK was hit at a national scale by the 2013/2014 storms, although the return periods differ with location. We also note that the 2013/2014 high water and waves were extreme due to the number of events, as well as the extremity of the 5 December 2013 "Xaver" storm, which had a very high return period at both case study sites. Our return period analysis shows that the national scale impact of this event is due to its coincidence with spring high tide at multiple locations as the tide and storm propagated across the continental shelf. Given that this event is such an outlier in the joint probability analyses of these observed data sets, and that the season saw several events in close succession, coastal defences appear to have provided a good level of protection. This type of assessment should be recorded alongside details of defence performance and upgrade, with other variables (e.g. river levels at estuarine locations) included and appropriate offsetting for linear trends (e.g. mean sea level rise) so that the storm-driven component of coastal flood events can be determined. Local offsetting of the mean trends in sea level allows long-term comparison of storm severity and also enables an assessment of how sea level rise is influencing return levels over time, which is important when considering long-term coastal resilience in strategic management plans.

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Economic damages from Hurricane Sandy attributable to sea level rise caused by anthropogenic climate change

Nature Communications ◽

10.1038/s41467-021-22838-1 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Benjamin H. Strauss ◽

Philip M. Orton ◽

Klaus Bittermann ◽

Maya K. Buchanan ◽

Daniel M. Gilford ◽

...

Keyword(s):

Climate Change ◽

Sea Level Rise ◽

Sea Level ◽

East Coast ◽

The United States ◽

Hurricane Sandy ◽

Water Levels ◽

Anthropogenic Climate Change ◽

Economic Damage ◽

Sea Levels

AbstractIn 2012, Hurricane Sandy hit the East Coast of the United States, creating widespread coastal flooding and over $60 billion in reported economic damage. The potential influence of climate change on the storm itself has been debated, but sea level rise driven by anthropogenic climate change more clearly contributed to damages. To quantify this effect, here we simulate water levels and damage both as they occurred and as they would have occurred across a range of lower sea levels corresponding to different estimates of attributable sea level rise. We find that approximately $8.1B ($4.7B–$14.0B, 5th–95th percentiles) of Sandy’s damages are attributable to climate-mediated anthropogenic sea level rise, as is extension of the flood area to affect 71 (40–131) thousand additional people. The same general approach demonstrated here may be applied to impact assessments for other past and future coastal storms.

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The Impact of Climate Change on States

International Community Law Review ◽

10.1163/18719732-12341465 ◽

2021 ◽

Vol 23 (2-3) ◽

pp. 115-132

Author(s):

Łukasz Kułaga

Keyword(s):

Climate Change ◽

International Law ◽

Sea Level Rise ◽

Sea Level ◽

The State ◽

Fundamental Change ◽

Sea Levels ◽

Impact Of Climate Change ◽

Potential Impact ◽

The Impact

Abstract The increase in sea levels, as a result of climate change in territorial aspect will have a potential impact on two major issues – maritime zones and land territory. The latter goes into the heart of the theory of the state in international law as it requires us to confront the problem of complete and permanent disappearance of a State territory. When studying these processes, one should take into account the fundamental lack of appropriate precedents and analogies in international law, especially in the context of the extinction of the state, which could be used for guidance in this respect. The article analyses sea level rise impact on baselines and agreed maritime boundaries (in particular taking into account fundamental change of circumstances rule). Furthermore, the issue of submergence of the entire territory of a State is discussed taking into account the presumption of statehood, past examples of extinction of states and the importance of recognition in this respect.

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Estimating contribution of high-frequency sea-level oscillations to the extreme sea levels in the Adriatic Sea

10.5194/egusphere-egu21-4602 ◽

2021 ◽

Author(s):

Krešimir Ruić ◽

Jadranka Šepić ◽

Maja Karlović ◽

Iva Međugorac

Keyword(s):

Time Series ◽

Sea Level ◽

High Frequency ◽

Adriatic Sea ◽

Tide Gauge ◽

Data Series ◽

Sea Levels ◽

Short Period ◽

Extreme Sea Levels ◽

Sea Level Oscillations

Extreme sea levels are known to hit the Adriatic Sea and to occasionally cause floods that produce severe material damage. Whereas the contribution of longer-period (T > 2 h) sea-level oscillations to the phenomena has been well researched, the contribution of the shorter period (T <&#160;2 h) oscillations is yet to be determined. With this aim, data of 1-min sampling resolution were collected for 20 tide gauges, 10 located at the Italian (north and west) and 10 at the Croatian (east) Adriatic coast. Analyses were done on time series of 3 to 15 years length, with the latest data coming from 2020, and with longer data series available for the Croatian coast. Sea level data were thoroughly checked, and spurious data were removed.&#160;For each station, extreme sea levels were defined as events during which sea level surpasses its 99.9 percentile value. The contribution of short-period oscillations to extremes was then estimated from corresponding high-frequency (T < 2 h) series. Additionally, for four Croatian tide gauge stations (Rovinj, Bakar, Split, and Dubrovnik), for period of 1956-2004, extreme sea levels were also determined from the hourly sea level time series, with the contribution of short-period oscillations visually estimated from the original tide gauge charts.&#160;&#160;Spatial and temporal distribution of contribution of short-period sea-level oscillations to the extreme sea level in the Adriatic were estimated. It was shown that short-period sea-level oscillation can significantly contribute to the overall extremes and should be considered when estimating flooding levels.&#160;

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The northern and the eastern Adriatic Sea floods: connecting the extreme sea-levels to cyclone pathways

10.5194/egusphere-egu21-8201 ◽

2021 ◽

Author(s):

Tihana Dević ◽

Jadranka Šepić ◽

Darko Koračin

Keyword(s):

Sea Level ◽

Tide Gauge ◽

Middle Eastern ◽

Origin Time ◽

Northern Adriatic ◽

Sea Levels ◽

North West ◽

Mediterranean Cyclones ◽

Extreme Sea Levels ◽

The Moment

An objective method for tracking pathways of cyclone centres over Europe was developed and applied to the ERA-Interim reanalysis atmospheric data (1979-2014). The method was used to determine trajectories of those Mediterranean cyclones which generated extreme sea levels along the northern and the eastern Adriatic coast during the period from 1979 to 2014. Extreme events were defined as periods during which sea level was above 99.95 percentile value of time series of hourly sea-level data measured at the Venice (northern Adriatic), Split (middle eastern Adriatic) and Dubrovnik (south-eastern Adriatic) tide-gauge stations. The cyclone pathways were tracked backwards from the moment closest to the moment of maximum sea level up to the cyclone origin time, or at most, up to 72 hours prior the occurrence of the sea-level maximum.Our results point out that extreme sea levels in Venice normally appear during synoptic situations in which a cyclone centre is located to the south-west and north-west of Venice, i.e., when it can be found over the Gulf of Genoa, or the Alps. On the contrary, extreme sea levels in Dubrovnik are usually associates with cyclone centres above the middle Adriatic, whereas floods in Split seem to appear during both above-described types of situations.Occurrence times and intensity of cyclones and extreme sea-levels was further associated with the NAO index. It has been shown that the deepest cyclones and corresponding extreme floods tend to occur during the negative NAO phase. &#160;&#160;

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Multiple drivers of extreme sea levels in the northern Adriatic Sea

10.5194/egusphere-egu21-8727 ◽

2021 ◽

Author(s):

Christian Ferrarin ◽

Piero Lionello ◽

Mirko Orlic ◽

Fabio Raicich ◽

Gianfausto Salvadori

Keyword(s):

Sea Level Rise ◽

Sea Level ◽

Adriatic Sea ◽

Driving Factors ◽

Northern Adriatic Sea ◽

Relative Sea Level ◽

Northern Adriatic ◽

Sea Levels ◽

Extreme Sea Levels ◽

Relative Sea Level Rise

Extreme sea levels at the coast result from the combination of astronomical tides with atmospherically forced fluctuations at multiple time scales. Seiches, river floods, waves, inter-annual and inter-decadal dynamics and relative sea-level rise can also contribute to the total sea level. While tides are usually well described and predicted, the effect of the different atmospheric contributions to the sea level and their trends are still not well understood. Meso-scale atmospheric disturbances, synoptic-scale phenomena and planetary atmospheric waves (PAW) act at different temporal and spatial scales and thus generate sea-level disturbances at different frequencies. In this study, we analyze the 1872-2019 sea-level time series in Venice (northern Adriatic Sea, Italy) to investigate the relative role of the different driving factors in the extreme sea levels distribution. The adopted approach consists in 1) isolating the different contributions to the sea level by applying least-squares fitting and Fourier decomposition; 2) performing a multivariate statistical analysis which enables the dependencies among driving factors and their joint probability of occurrence to be described; 3) analyzing temporal changes in extreme sea levels and extrapolating possible future tendencies. The results highlight the fact that the most extreme sea levels are mainly dominated by the non-tidal residual, while the tide plays a secondary role. The non-tidal residual of the extreme sea levels is attributed mostly to PAW surge and storm surge, with the latter component becoming dominant for the most extreme events. The results of temporal evolution analysis confirm previous studies according to which the relative sea-level rise is the major driver of the increase in the frequency of floods in Venice over the last century. However, also long term variability in the storm activity impacted the frequency and intensity of extreme sea levels and have contributed to an increase of floods in Venice during the fall and winter months of the last three decades.

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