scholarly journals AN ADVANCED STATISTICAL EXTREME VALUE MODEL FOR EVALUATING STORM SURGE HEIGHTS CONSIDERING SYSTEMATIC RECORDS AND SEA LEVEL RISE SCENARIO

2011 ◽  
Vol 1 (32) ◽  
pp. 23 ◽  
Author(s):  
Christoph Mudersbach ◽  
Juergen Jensen
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Likelihood Estimation ◽  
Extreme Value ◽  
Water Levels ◽  
Extreme Value Analysis ◽  
Value Analysis ◽  
Additional Approach ◽  
Extreme Value Model ◽  
Value Model

In this paper, a non-stationary extreme value analysis approach is introduced in order to determine coastal design water levels for future time horizons. The non-stationary statistical approach is based on the Generalized Extreme Value (GEV) distribution and a L-Moment parameter estimation as well as a Maximum-Likelihood-estimation. An additional approach considers sea level rise scenarios in the non-stationary extreme value analysis. All the methods are applied to the annual maximum water levels from 1849-2007 at the German North Sea gauge at Cuxhaven. The results show, that the non-stationary GEV approach is suitable for determining coastal design water levels.

scholarly journals Determining Extreme Still Water Levels for Design and Planning Purposes Incorporating Sea Level Rise: Sydney, Australia

Atmosphere ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 95
Author(s):  
Phil J. Watson
Keyword(s):  
Sea Level Rise ◽  
Water Level ◽  
Sea Level ◽  
Tide Gauge ◽  
Water Levels ◽  
Extreme Value Analysis ◽  
Tide Gauge Record ◽  
Value Analysis ◽  
Mean Sea Level ◽  
The Impact

This paper provides an Extreme Value Analysis (EVA) of the hourly water level record at Fort Denison dating back to 1915 to understand the statistical likelihood of the combination of high predicted tides and the more dynamic influences that can drive ocean water levels higher at the coast. The analysis is based on the Peaks-Over-Threshold (POT) method using a fitted Generalised Pareto Distribution (GPD) function to estimate extreme hourly heights above mean sea level. The analysis highlights the impact of the 1974 East Coast Low event and rarity of the associated measured water level above mean sea level at Sydney, with an estimated return period exceeding 1000 years. Extreme hourly predictions are integrated with future projections of sea level rise to provide estimates of relevant still water levels at 2050, 2070 and 2100 for a range of return periods (1 to 1000 years) for use in coastal zone management, design, and sea level rise adaptation planning along the NSW coastline. The analytical procedures described provide a step-by-step guide for practitioners on how to develop similar baseline information from any long tide gauge record and the associated limitations and key sensitivities that must be understood and appreciated in applying EVA.

Design conditions for waves and water levels using extreme value analysis with covariates

2019 ◽  
Vol 173 ◽  
pp. 851-866 ◽  
Author(s):  
Graham Feld ◽  
David Randell ◽  
Emma Ross ◽  
Philip Jonathan
Keyword(s):  
Extreme Value ◽  
Water Levels ◽  
Extreme Value Analysis ◽  
Value Analysis

scholarly journals The Influence of Hindcast Modeling Uncertainty on the Prediction of High Return Period Wave Conditions

2004 ◽  
Author(s):  
Daniel C. Brooker ◽  
Geoffrey K. Cole ◽  
Jason D. McConochie
Keyword(s):  
Return Period ◽  
Extreme Value Distribution ◽  
Likelihood Estimation ◽  
Extreme Value ◽  
Extreme Value Analysis ◽  
Random Errors ◽  
Value Analysis ◽  
Simulation Techniques ◽  
Modeling Uncertainties ◽  
Wave Conditions

Extreme value analysis for the prediction of long return period met-ocean conditions is often based upon hindcast studies of wind and wave conditions. The random errors associated with hindcast modeling are not usually incorporated when fitting an extreme value distribution to hindcast data. In this paper, a modified probability distribution function is derived so that modeling uncertainties can be explicitly included in extreme value analysis. Maximum likelihood estimation is then used to incorporate hindcast uncertainty into return value estimates and confidence intervals. The method presented here is compared against simulation techniques for accounting for hindcast errors. The influence of random errors within modeled datasets on predicted 100 year return wave estimates is discussed.

scholarly journals Numerical Investigation of Storm Surge in Kong Port in the Persian Gulf

2019 ◽  
Author(s):  
Amir Hossein Mahdavi ◽  
Hamid Ansari Sharghi
Keyword(s):  
Sea Level Rise ◽  
Engineering Design ◽  
Sea Level ◽  
Storm Surge ◽  
Storm Surges ◽  
Wave Model ◽  
Water Level Fluctuations ◽  
Extreme Value Analysis ◽  
Value Analysis ◽  
Mean Sea Level

Storm surge is generated by the integration of waves, tide and wind setup that is resulted in unwanted mean sea level rise and coastal flooding. The estimation of accurate storm surge is essential for the engineering design of coastal structures. In this study, we estimated the respond of mean sea level winds, tide, waves, and sea-level rise using a local coastal model. A fully coupled hydrodynamic and wave model was implemented to obtain storm surge from different phenomena. The simulations of water level fluctuations due to these parameters were analyzed with the wind forces identified with tidal observations in the Port of Kong. Extreme value analysis was performed to determine the fluctuations associated with different return periods. These data were combined by sea-level rise projections are combined with resulted value. The worst and best scenario of storm surges for each return period were determined for engineering design purposes.

Extreme Coastal Inundation Under Different Climate Scenarios: Fourchon Junction Case Study

2021 ◽  
Author(s):  
Octavio Sequeiros ◽  
Sergio Jaramillo
Keyword(s):  
Boundary Conditions ◽  
Sea Level Rise ◽  
Sea Level ◽  
Return Period ◽  
Wave Crest ◽  
Design Parameters ◽  
Extreme Value Analysis ◽  
Future Scenarios ◽  
Barrier Beach ◽  
Value Analysis

Abstract Port Fourchon Junction is located within Chevron's Fourchon Terminal, just south of Port Fourchon and is operated by Shell Pipeline Company LP. This manifold metering station is a critical junction for the Mars Corridor oil, as oil production from Mars (MC-807), Ursa (MC-809), Titan (MC-941), Who Dat (MC-547), Medusa (MC-582), and Olympus (MC-807B) flows through this station via a 24" pipeline. Port Fourchon is at the edge of the Mississippi delta facing the sea, one of the world's most vulnerable low-elevation coastal zones. It is highly exposed to storm surge and wave-induced inundation under hurricanes which regularly visit the Gulf of Mexico. In addition, it experiences one of the largest rates of subsidence in the world, which combined with sea level rise, will increase the site vulnerability in the coming decades. This study assesses present and future scenarios of subsidence and sea level rise under extreme metocean conditions induced by hurricanes and their impact on Port Fourchon Junction. Local effects such as the differential settlement of the barrier beach have been also considered. Using results from the numerical model XBeach, a set of different present and future scenarios are modelled under extreme metocean conditions. These conditions and the subsequent design parameters calculated, are not obtained through traditional extreme value analysis methods, instead, they are estimated through the influence of boundary conditions forced with the corresponding return period values of the parameters. Boundary conditions for the simulations are extracted from Grand Isle and Port Fourchon sea level observations, and from FEMA and the Water Institute of the Gulf simulations. Port Fourchon site should be subject to flooding for 10-year return period conditions based on Grand Isle observations. For 5-6 years return period conditions some degree of milder partial flood should also be expected. This is well captured by the model. While the highest inundating level is mostly dependent on winds, waves and surge acting together, surge is the single most critical parameter that defines the asset's base inundation level. Design future conditions based on surge extreme from FEMA simulations are recommended over surge extremes derived from Grand Isle observations. The barrier beach and the breakwaters play a key factor in sheltering site from waves and surge. Even when submerged under extreme high return period conditions they dissipate the waves ensuring that the maximum water level (wave crest elevation) on site is lower than would otherwise be without them. It is then important to maintain them fit for purpose during the entire lifespan of the asset. Both Grand Isle and Port Fourchon subsidence scenarios yield similar results. Based on the importance of Port Fourchon Junction facilities, the design criteria obtained, and the higher subsidence level observed at Port Fourchon (compared to Grand Isle), it is recommended that a 1000-year return period and future scenario based on FEMA surge level and Port Fourchon Relative Sea Level Rise (RSLR) is adopted for design. The subsidence associated to this scenario is 9.8 mm/year. The sea level rise associated to this scenario is 2 mm/year.

scholarly journals A New Extreme Value Model with Different Copula, Statistical Properties and Applications

2021 ◽  
pp. 1015-1035
Author(s):  
Hanaa Elgohari ◽  
Haitham M. Yousof
Keyword(s):  
Maximum Likelihood ◽  
Likelihood Estimation ◽  
Real Data ◽  
Extreme Value ◽  
Model Parameters ◽  
Finite Sample ◽  
Mathematical Properties ◽  
Maximum Likelihood Estimations ◽  
Extreme Value Model ◽  
Value Model

In this article, we defined and studied a new distribution for modeling extreme value. Some of its mathematical properties are derived and analyzed. Simple types copula is employed for proposing many bivariate and multivariate type extensions. Method of the maximum likelihood estimation is employed to estimate the model parameters. Graphically, we perform the simulation experiments to assess of the finite sample behavior of the maximum likelihood estimations. Three applications are presented for measuring the flexibility of the new model is illustrated using three real data applications.

scholarly journals Nonstationary Extreme Value Analysis of Nearshore Sea-State Parameters under the Effects of Climate Change: Application to the Greek Coastal Zone and Port Structures

2021 ◽  
Vol 9 (8) ◽  
pp. 817
Author(s):  
Panagiota Galiatsatou ◽  
Christos Makris ◽  
Yannis Krestenitis ◽  
Panagiotis Prinos
Keyword(s):  
Climate Change ◽  
Sea Level ◽  
Storm Surges ◽  
Extreme Value ◽  
Extreme Value Analysis ◽  
Extreme Wave ◽  
Sea State ◽  
Value Analysis ◽  
Wave Characteristics ◽  
Failure Probabilities

In the present work, a methodological framework, based on nonstationary extreme value analysis of nearshore sea-state parameters, is proposed for the identification of climate change impacts on coastal zone and port defense structures. The applications refer to the estimation of coastal hazards on characteristic Mediterranean microtidal littoral zones and the calculation of failure probabilities of typical rubble mound breakwaters in Greek ports. The proposed methodology hinges on the extraction of extreme wave characteristics and sea levels due to storm events affecting the coast, a nonstationary extreme value analysis of sea-state parameters and coastal responses using moving time windows, a fitting of parametric trends to nonstationary parameter estimates of the extreme value models, and an assessment of nonstationary failure probabilities on engineered port protection. The analysis includes estimation of extreme total water level (TWL) on several Greek coasts to approximate the projected coastal flooding hazard under climate change conditions in the 21st century. The TWL calculation considers the wave characteristics, sea level height due to storm surges, mean sea level (MSL) rise, and astronomical tidal ranges of the study areas. Moreover, the failure probabilities of a typical coastal defense structure are assessed for several failure mechanisms, considering variations in MSL, extreme wave climates, and storm surges in the vicinity of ports, within the framework of reliability analysis based on the nonstationary generalized extreme value (GEV) distribution. The methodology supports the investigation of future safety levels and possible periods of increased vulnerability of the studied structure to different ultimate limit states under extreme marine weather conditions associated with climate change, aiming at the development of appropriate upgrading solutions. The analysis suggests that the assumption of stationarity might underestimate the total failure probability of coastal structures under future extreme marine conditions.

Modeling European hot spells using extreme value analysis

2014 ◽  
Vol 58 (3) ◽  
pp. 193-207 ◽  
Author(s):  
C Photiadou ◽  
MR Jones ◽  
D Keellings ◽  
CF Dewes
Keyword(s):  
Extreme Value ◽  
Extreme Value Analysis ◽  
Value Analysis ◽  
Hot Spells
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