Search

Multi-mission satellite altimetry data have been used to study the spatial and temporal variability in global storm surge water levels. This was done by means of a time-dependent extreme value analysis applied to the monthly maximum detided water levels. To account for the limited temporal resolution of the satellite data, the data were first stacked on a 5∘× 5∘ grid. Moreover, additional scaling was applied to the extreme value analysis for which the scaling factors were determined by means of a resampling method using reanalysis data. In addition to the conventional analysis using data from tide gauges, this study provides an insight in the ocean-wide storm surge properties. Nonetheless, where possible, results were compared to similar information derived from tide gauge data. Except for secular changes, the satellite-derived results are comparable to the information derived from tide gauges (correlation > 0.5), although the tide gauges show more local variability. Where limited correlation was observed for the secular change, it was suggested that the satellites may not be able to fully capture the temporal variability in the short-lived, tropical storms, as opposed to extra-tropical storms., Water Resources, Physical and Space Geodesy, Mathematical Physics

This paper describes a major update to the quasi-global, higher-frequency sea-level dataset known as GESLA (Global Extreme Sea Level Analysis). Versions 1 (released 2009) and 2 (released 2016) of the dataset have been used in many published studies, across a wide range of oceanographic and coastal engineering-related investigations concerned with evaluating tides, storm surges, extreme sea levels, and other related processes. The third version of the dataset (released 2021), presented here, contains double the number of years of data, and nearly four times the number of records, compared to Version 2. The dataset consists of records obtained from multiple sources around the world. This paper describes the assembly of the dataset, its processing, and its format, and outlines potential future improvements

The purpose of the paper is to analyse the possible parameters of extratropical cyclones (ETCs) as they would occur in the Baltic Sea area at the end of the 21st century and in the past during the Holocene thermal maximum. Using a modelling system composed of the Weather Research and Forecasting (ARW-WRF) atmospheric model, Finite Volume Community Ocean Model (FVCOM), and surrogate background conditions, the results showed that changes in cyclone parameters are more profound under steeper climate change scenarios (RCP8.5) and under higher air temperatures. Most likely, the North Atlantic ETCs will become slightly stronger, but also the uncertainty increases. Nonlinear interactions between ice melt, North Atlantic current systems and atmospheric parameters probably induce an uncertainty both into future and past storminess reconstructions.

In the context of climate change and associated sea level rise, coastal dunes can provide an essential contribution to coastal protection against wave attack and flooding. Since dunes are highly dynamic systems, their potential safety levels are related to their long-term development, varying in time and space, however pertinent research that ties those aspects together are generally scarce. The objective of this study is to analyze the long-term development of a young coastal foredune at the Eiderstedt peninsula, Germany and assess its coastal protection potential. This research presents (i) a novel semi-automated Dune Toe Tracking (DTT) method to systematically extract dune toes from cross-shore elevation profiles; (ii) established tools to derive the extraction of characteristic dune parameters and (iii) a newly defined Critical Storm Surge Level (CSSL) to relate spatio-temporal dune growth with coastal storm surge protection. Based on geospatial survey data, initial dune formation was identified in the 1980s. By 2015, the foredune had developed over a 6.5 km coastal stretch with a mean annual growth of 7.4m³/m. During the course of dune evolution, the seaward dune toe shifted seaward by an average of 2.3m/yr, while simultaneously increasing in height by an average of 1.1 cm/yr. Overall, the foredune formation established a new line of defense in front of an existing dike/dune line that provides spatially varying protection against a mean CSSL of 3.4m + NHN and can serve as an additional buffer against wave attack during severe storm events.

The purpose of the paper is to analyse the possible parameters of extratropical cyclones (ETCs) as they would occur in the Baltic Sea area at the end of the 21st century and in the past during the Holocene thermal maximum. Using a modelling system composed of the Weather Research and Forecasting (ARW-WRF) atmospheric model, Finite Volume Community Ocean Model (FVCOM), and surrogate background conditions, the results showed that changes in cyclone parameters are more profound under steeper climate change scenarios (RCP8.5) and under higher air temperatures. Most likely, the North Atlantic ETCs will become slightly stronger, but also the uncertainty increases. Nonlinear interactions between ice melt, North Atlantic current systems and atmospheric parameters probably induce an uncertainty both into future and past storminess reconstructions.

This paper describes a major update to the quasi-global, higher-frequency sea-level dataset known as GESLA (Global Extreme Sea Level Analysis). Versions 1 (released 2009) and 2 (released 2016) of the dataset have been used in many published studies, across a wide range of oceanographic and coastal engineering-related investigations concerned with evaluating tides, storm surges, extreme sea levels, and other related processes. The third version of the dataset (released 2021), presented here, contains double the number of years of data, and nearly four times the number of records, compared to Version 2. The dataset consists of records obtained from multiple sources around the world. This paper describes the assembly of the dataset, its processing, and its format, and outlines potential future improvements

Dune erosion during storm surges can lead to excessive damage to the dune system with devastating floods as a potential consequence. A risk assessment of areas protected by dunes can be facilitated by an understanding and description of the physical processes that take place. Field measurements, knowledge of underlying processes and numerical modelling have developed with time, which enabled a more comprehensive description and new predictive techniques. This review concerns dune erosion in the collision regime, and summarises relevant observations, describes underlying processes and explains existing models predicting dune erosion. Observations of dune erosion consist of field observations, laboratory experiments and manipulative field campaigns. The underlying physical processes that contribute to dune erosion are divided into processes that contribute to sediment transport due to hydrodynamic forcing, which occurs in the surf and swash zone, and sediment transport due to avalanching, which occurs in the swash zone, on the dune face and on the dune crest. The existing dune erosion models that are discussed here contain (empirical) equilibrium profile models and process-based models, which can both be a valuable tool for the risk assessment of storm surges. However, model uncertainties still remain, as specific processes are not yet fully understood and described. Examples are the influences of wave obliquity, sediment grain size, and vegetation on the dune face. By improving our knowledge through research and reducing these uncertainties, we can further improve our predictive models. This could eventually lead to more accurate predictions, more complete risk assessments, and sandy coastlines which are more resilient to excessive dune erosion and possible floods., Coastal Engineering, Environmental Fluid Mechanics, Hydraulic Engineering

This paper describes a major update to the quasi-global, higher-frequency sea-level dataset known as GESLA (Global Extreme Sea Level Analysis). Versions 1 (released 2009) and 2 (released 2016) of the dataset have been used in many published studies, across a wide range of oceanographic and coastal engineering-related investigations concerned with evaluating tides, storm surges, extreme sea levels, and other related processes. The third version of the dataset (released 2021), presented here, contains double the number of years of data, and nearly four times the number of records, compared to Version 2. The dataset consists of records obtained from multiple sources around the world. This paper describes the assembly of the dataset, its processing, and its format, and outlines potential future improvements.

Previous version contained the return levels of coastal significant wave height and sea surface elevation along the Caribbean coastlines corresponding to the periods of 10, 50, 100, 200 and 500 years. The return periods have been computed fitting a Generalised Pareto Distribution to a set of hydrodynamic-wave coupled ocean simulations forced with 1000 synthetic tropical cyclones. See the paper Martin et al (under review) for details. -- The file (Return_levels.mat) contains a Matlab table (with header names) indicating latitude, longitude and the return levels described above, named as Hs (significant wave height) and SSE (sea surface elevation). -- Three other datasets have been included, with the subsample of the Tropical Cyclones selected for the study (Subsample.mat), the geographic data of the coastal grid points used for our analysis (Coastaline.mat), and finally a dataset with the results of the analysis presented in the paper (Results_4_runs.mat). All datasets are provided in a .mat file, generated using Matlab. -- First dataset contains a Matlab table (with header names) indicating latitude and longitude, radius of maximum wind speed, minimum pressure and maximum wind speed a long the track of the Tropical Cyclone, for the 1000 samples selected. -- Second dataset provides both Latitude and Longitude of the coastal grid points used for the analysis. -- The last dataset contains a Matlab table (with header names) where the first column represents the Tropical Cyclone, columns 2,3 and 4 contain the maximum of sea surface elevation (SSE) during the lifetime of the Tropical Cyclone for each coastal point, for the 3 decoupled runs, wind-forced only, pressure-forced only and wind and pressure respectively. The next 4 columns contain the values of the variables for the coupled simulations with WWM-III, maximum significant wave height (Hs), maximum SSE, median of Peak Direction (Dp) and median of Peak period (Tp). All these variables contain a description in the dat

In the Mediterranean Sea, coastal extreme sea levels are mainly caused by storm surges driven by atmospheric pressure and surface winds from extratropical cyclones. In addition, wind-waves generated by the same atmospheric perturbations may also contribute to coastal extremes through wave setup (temporal rise above the mean sea level due to dissipation and breaking of waves in shallow waters close to the shore). This study investigates the spatial and temporal variability of coastal extreme sea levels in the Mediterranean basin, using a new ocean hindcast generated with a coupled hydrodynamic-wave model that simulates storm surges and wind-waves. The numerical simulation covers the period 1950-2021 with high temporal sampling (1h) and at unprecedented spatial resolution for a basin scale analysis, that reaches 200 m along the coastlines. Coastal storm surges and wave heights are validated with available observations (tide gauges, waves buoys and satellites). Comparison against tide gauges shows an average RMSE of 7.5 cm (7.7 cm for extreme events) and mean linear correlation of 0.64 for the whole period. Similarly, comparison of simulated and observed significant wave height shows good agreement, with RMSE lower than 0.25 m and a coefficient correlation as high as 0.95. The results confirm that coastal extreme sea levels are more likely to be located in regions with wide continental shelves favouring the wind contribution to storm surges along with shallow waters that favour wave setup induced by depth-breaking. The contribution of waves to coastal extreme sea levels has been quantified, using the hindcast in combination with an uncoupled simulation and has been shown to be significant, with an assessed wave setup spatial footprint at regional scale and observed maximum sea levels increased by up to 120% in the presence of waves.

Extreme sea levels and coastal flooding can cause devastating socio-economic damages and even loss of lives. Robust and timely risk mitigation requires knowledge of recurrence frequencies, but such estimates are riddled with uncertainties, especially regarding high-impact, low-probability events. In the North Sea–Baltic Sea region, considerable inter- and intra-decadal variability mean that the risks of present-day, wind-driven extreme sea levels are not fully determined. This knowledge gap is becoming more urgent for decision-makers and stakeholders since mitigation of the impacts of current and future flooding hazards, e.g. by coastal adaptation schemes, ideally requires detailed knowledge on the current and future storm-surge regime.In the present study, we investigate the wind-driven sea-level responses across the entirety of the complex Danish coastlines. We use an idealised framework to map the ranges of critical wind directions systematically by applying an advanced oceanographic model for storm surges driven by synthetic wind fields. We find that the modelled extreme water levels increase linear-to-quadratically with increased wind speed. This increase shows no signs of levelling off even for static winds of 40ms−1, although this finding is dependent on the wind stress parameterisation, which becomes uncertain for such strong wind forcing. The magnitudes of the resulting extreme water levels are highest in the Wadden Sea region in the southeastern North Sea. Still, when taking local sea-level variability into account, the most extreme incidents are undoubtedly generated in the western Baltic Sea.Hereafter, and based on the same synthetic wind fields, we investigate a complementary methodology’s potential to generalise the synthetic modelling results. For this purpose, site-specific relations between the dynamic wind forcing (i.e. wind speed and wind direction), parameters defining the local conditions and extreme sea levels are determined based on the dynami

Climate change and increased coastal urbanization are causing low-lying coastlines to become increasingly susceptible to the threat of extreme water levels and coastal flooding. Robust decision-making on adaptation in the coastal zone, based on reliable ocean-modelling tools, is therefore crucially contingent on accurate assessments of current and future storm surge hazards. This accuracy relies considerably on the quality of the wind forcing used in the ocean models. In this paper, we use a high-resolution, regional 3D ocean model (HBM) covering the North Sea and Baltic Sea to simulate extreme water levels during three extreme storm surge events with different dynamics and patterns, in order to assess their impacts along Denmark’s coastlines, which are of varying levels of complexity. We demonstrate that the model is able to reproduce the observed extreme high-water levels accurately, indicating that the system is well suited for producing simulations of present and future projections of extreme storm surges with high resulting impacts and damage potentials. Additionally, we quantify the level at which acknowledged deficiencies in the otherwise most suitable atmospheric forcing data set influence the results of the storm surge simulations. We found that reducing the temporal resolution of the forcing data – that is, replacing two out of every six time stamps with linearly interpolated values – is preferable to using the original forcing data set when recurring noise is present in these time stamps. As a result, for given storm surge events, and depending on the stage reached in the storm’s evolution, mean absolute errors can be reduced by 4.5 cm. This emphasizes the importance of considering such model fluctuations when coupling high-resolution atmosphere and ocean models.

We investigate the impact of wave-dependent stress on surge modelling, from case studies in the North Sea, using a global ocean model forced with a wave-atmosphere coupled model. We select the storms with the largest surges and a range of sea state development from young to mature seas. The modelled surges are compared to tide gauges and altimeter data. The ocean model is able to accurately predict storm surges in coastal areas. The consistency of the model outputs, the altimeter, and the tide gauge data confirms the accuracy of altimeters for storm surge measurements. We show that using a wave-dependent rather than a wind-dependent only stress formulation gives more accurate surge simulations when the sea state is young and the sea rougher. Taking into account the waves in the stress formulation has a significant impact on the surges (up to 20 cm).

We investigate the impact of wave-dependent stress on surge modelling, from case studies in the North Sea, using a global ocean model forced with a wave-atmosphere coupled model. We select the storms with the largest surges and a range of sea state development from young to mature seas. The modelled surges are compared to tide gauges and altimeter data. The ocean model is able to accurately predict storm surges in coastal areas. The consistency of the model outputs, the altimeter, and the tide gauge data confirms the accuracy of altimeters for storm surge measurements. We show that using a wave-dependent rather than a wind-dependent only stress formulation gives more accurate surge simulations when the sea state is young and the sea rougher. Taking into account the waves in the stress formulation has a significant impact on the surges (up to 20 cm).

We investigate the impact of wave-dependent stress on surge modelling, from case studies in the North Sea, using a global ocean model forced with a wave-atmosphere coupled model. We select the storms with the largest surges and a range of sea state development from young to mature seas. The modelled surges are compared to tide gauges and altimeter data. The ocean model is able to accurately predict storm surges in coastal areas. The consistency of the model outputs, the altimeter, and the tide gauge data confirms the accuracy of altimeters for storm surge measurements. We show that using a wave-dependent rather than a wind-dependent only stress formulation gives more accurate surge simulations when the sea state is young and the sea rougher. Taking into account the waves in the stress formulation has a significant impact on the surges (up to 20 cm).

We perform the first global analysis of the spatial footprints of storm surges, using observed and simulated storm surge data. Three different techniques are applied to quantify the spatial footprints: clustering analysis, percentage of co‐occurrence, and joint probability analysis. The capability of the simulated data to represent the observed storm surge footprints is demonstrated. Results lead to the identification of coastline stretches prone to be impacted simultaneously by the same storm surge events. The spatial footprint sizes differ around the globe, partially conditioned by the geography of the coastline, that is, more irregular coastlines consist of a larger number of different storm surge clusters with varying footprint sizes. For the northwestern Atlantic, spatial footprints of storm surges vary when specifically accounting for tropical cyclones, using storm track information in the storm surge simulations. Our results provide important new insights into the spatial footprints of storm surges at the global scale and will help to facilitate improvements in how coastal flood risk is identified, assessed, and managed, by taking these spatial features into account.

In the framework of the EU funded research project under the H2020 framework programme ANYWHERE (Enhancing emergency management and response to extreme weather and climate events) a system to integrate both hazard and vulnerability information has been developed. Out of 6 pilot projects for 6 different locations in Europe, In the application to Catalunya, A4CAT has been developed in this thesis work, it processes real time observations from different networks (sensors, weather radars etc). A4CAT (ANYWHERE for Catalunya), a web-based platform has been developed by considering the diverse weather conditions of Catalunya, including special type of warnings and observations related to the landscape of Catalunya like forest-fires, sea storms, wind, heat waves, air quality, floods and the general warnings like, rivers, rain, snow. A4CAT is an advanced web-based decision support system for managing, simulating, and forecasting natural hazards to make intelligent decisions in realtime for extreme weather events. For Catalunya, almost all types of weather conditions are observed by the input of Catalunya’s meteocat and civil protection agencies and their respective hazard warning inputs are included in this system. A4CAT handles the management of all the hazard warnings on the front-end, communicates with the A4EU back-end for the retrievel, updation and synchronization of information related to the weather warnings in real time and helps in responding effectively to such warnings.

The dependence between extreme storm surges and wind waves is assessed statistically along the global coasts using the outputs of two numerical models consistently forced with the same atmospheric fields. We show that 55% of the world coastlines face compound storm surge wave extremes. Hence, for a given level of probability, neglecting these dependencies leads to underestimating extreme coastal water levels. Dependencies are dominant in midlatitudes and are likely underestimated in the tropics due to limited representation of tropical cyclones. Furthermore, we show that in half of the areas with dependence, the estimated probability of occurrence of coastal extreme water levels increases significantly when it is accounted for. Translated in terms of return periods, this means that along 30% of global coastlines, extreme water levels expected at most once in a century without considering dependence between storm surges and waves become a 1 in 50-year event.

We present an idealized network model for storm surges in the Wadden Sea, specifically including a time-dependent wind forcing (wind speed and direction). This extends the classical work by H.A. Lorentz who only considered the equilibrium response to a steady wind forcing. The solutions obtained in the frequency domain for the linearized shallow-water equations in a channel are combined in an algebraic system for the network. The velocity scale that is used for the linearized friction coefficient is determined iteratively. The hindcast of the storm surge of 5 December 2013 produces credible time-varying results. The effects of storm and basin parameters on the peak surge elevation are the subject of a sensitivity analysis. The formulation in the frequency domain reveals which modes in the external forcing lead to the largest surge response at coastal stations. There appears to be a minimum storm duration, of about 3–4 h, that is required for a surge to attain its maximum elevation. The influence of the water levels at the North Sea inlets on the Wadden Sea surges decreases towards the shore. In contrast, the wind shearing generates its largest response near the shore, where the fetch length is at its maximum, Numerical Analysis

We present an idealized network model for storm surges in the Wadden Sea, specifically including a time-dependent wind forcing (wind speed and direction). This extends the classical work by H.A. Lorentz who only considered the equilibrium response to a steady wind forcing. The solutions obtained in the frequency domain for the linearized shallow-water equations in a channel are combined in an algebraic system for the network. The velocity scale that is used for the linearized friction coefficient is determined iteratively. The hindcast of the storm surge of 5 December 2013 produces credible time-varying results. The effects of storm and basin parameters on the peak surge elevation are the subject of a sensitivity analysis. The formulation in the frequency domain reveals which modes in the external forcing lead to the largest surge response at coastal stations. There appears to be a minimum storm duration, of about 3–4 h, that is required for a surge to attain its maximum elevation. The influence of the water levels at the North Sea inlets on the Wadden Sea surges decreases towards the shore. In contrast, the wind shearing generates its largest response near the shore, where the fetch length is at its maximum, Numerical Analysis

The past 12 years have seen significant steps forward in the science and practice of coastal flood analysis. This paper aims to recount and critically assess these advances, while helping identify next steps for the field. This paper then focuses on a key problem, connecting the probabilistic characterization of flood hazards to their physical mechanisms. Our investigation into the effects of natural structure on the probabilities of storm surges shows that several different types of spatial-, temporal-, and process-related organizations affect key assumptions made in many of the methods used to estimate these probabilities. Following a brief introduction to general historical methods, we analyze the two joint probability methods used in most tropical cyclone hazard and risk studies today: the surface response function and Bayesian quadrature. A major difference between these two methods is that the response function creates continuous surfaces, which can be interpolated or extrapolated on a fine scale if necessary, and the Bayesian quadrature optimizes a set of probability masses, which cannot be directly interpolated or extrapolated. Several examples are given here showing significant impacts related to natural structure that should not be neglected in hazard and risk assessment for tropical cyclones including: (1) differences between omnidirectional sampling and directional-dependent sampling of storms in near coastal areas; (2) the impact of surge probability discontinuities on the treatment of epistemic uncertainty; (3) the ability to reduce aleatory uncertainty when sampling over larger spatial domains; and (4) the need to quantify trade-offs between aleatory and epistemic uncertainties in long-term stochastic sampling.

This paper analyses the meteorological conditions and the specific peak flows of 24 catastrophic floods that affected NE Iberian Peninsula in the period 1842–2000. We classify these floods according to the affected area, peak flow magnitude, and damages. Additionally, the NOAA 6 Hourly 20th Century V2 Reanalysis Data Composites have been used to analyze the synoptic conditions during each flood and to evaluate several stability indices, such as the convective available potential energy (CAPE), or the lift index. We found a good correlation between stability indices and the season when the flood occurred. For instance, if maximum CAPE is considered, larger values are found for summer floods, moderate for autumn, and low values during winter floods. We select 5 representative episodes occurred in different seasons and areas to describe in detail the synoptic conditions and to show the temporal evolution of the stability indices. In one the summer floods analyzed in detail, the largest instability, according to all the convective indices, is found. On the contrary, the winter case shows very low values of the convective indices, and autumn cases lay in between. During the other analyzed summer flood instability was low but snow thaw played an important role in producing the flood. Regarding hydrological variables, clear differences between floods occurred at the coast or at the Pyrenees are found. Coastal specific peak flows are larger than Pyrenean ones, especially for small catchment areas. We also combine meteorological (rainfall duration, CAPE), hydrological (specific peak flow) and geomorphological (catchment area) variables to show that for many of the analyzed floods these variables are related: the specific peak flow generally shows larger values when CAPE is also large. However some differences appear depending on the season and area. In those summer floods, where snow thaw played doesn’t played any role, either Pyrenean or coastal, specific peak flow seems to, Peer Reviewed, Postprint (published version)

The coasts of Denmark, Germany and Norway face similar hazards from storm surges governed by eastward propagating atmospheric lows. Surge and tide levels, as well as their corresponding impacts, vary between storms and location. The exposure and physical vulnerability of the coastline is also not evenly distributed. National methodologies for assessing extreme events generally differ in some way. For example, the statistical methods applied in extreme value analysis, projections of future changes in extremes, and/or approaches for dealing with coastal flood risks. This includes local to regional climate change projections for future sea extremes, and, for instance, variations due to location, morphodynamic change, and glacio-isostatic adjustment. Next, the transformation of this knowledge to concrete impact and design measures and its use in national and local governance adaptation schemes in the three countries is discussed. Here, national approaches to deal with risk, risk acceptance and uncertainty vary, among other factors, as a result of the different assessments of extreme events. In hazard and vulnerability assessments, for instance, where results are highly dependent on the quality of the underlying observational data and statistical methods in use, it is necessary to gain a deeper understanding of the physical processes (i.e. the atmospheric and oceanographic genesis of storms) in order to make robust strategies for adaptation and risk reduction. Inasmuch as the countries bordering the northeast Atlantic Ocean and the North Sea deal with similar coastal hazards and climate change challenges, the development of enhanced scientific transnational collaboration to share knowledge and views regarding future impact from storm surges is suggested. This will provide more robust measures of mitigation and adaptation and it will secure a wider dissemination of results across levels of governance and between the northern European countries.

Storm surge impacts on the Limfjord coasts of Denmark are exacerbated by the expansion of the Thyborøn Channel that causes increased water transport into the fjord from the North Sea. This, in combination with sea level rise, jeopardizes the strength of existing flood protection and challenges the local municipalities to implement additional measures. For the fjord towns of Thyborøn (pop. 2100, located towards the North Sea by the Thyborøn Channel) and Løgstør (pop. 4000, located approximately 80 km east from the North Sea) flood hazard, vulnerability, and risk assessments and mapping are combined with community resilience studies to provide the corresponding municipalities with a more elaborate knowledge platform for climate adaptation and disaster risk reduction. Community resilience is investigated in four dimensions (information & communication, community competence, social capital, and institutional capacity) from +25 semi-structured interviews conducted with local citizens, municipal level employees as well as national government officials. Despite facing the same flood hazards, the two communities have different h istories, social structures, and previous flood experiences and, accordingly, have different resilience strengths and limitations inherent. Thyborøn emerged over the past century as a fisheries town protected from the North Sea by large sea dikes constructed by the national government. Life in a harsh physical environment and no significant flood accounts in decades, means that neither the community nor the municipality perceives floods as any immediate threat. Municipal adaptation planning is slowly forming but hitherto without engaging the local community, and the town has no formal emergency preparedness plan. In contrast, the medieval town of Løgstør last experienced severe floods in 1981 and 2005 which led to the construction of a sea wall, community involvement, and detailed emergency management setup. The Thyborøn community has a reputati

According to DOD, its U.S. infrastructure is vulnerable to the potential impacts of climate change. These could affect DOD s readiness and fiscal exposure, and DOD has begun to plan for adaptation actions designed to improve infrastructure resilience. GAO was asked to assess DOD s actions to adapt its U.S. infrastructure to the challenges of climate change. This report (1) describes potential impacts identified by DOD that may affect its infrastructure; (2) evaluates DOD s efforts to conduct vulnerability assessments; (3) assesses how DOD is accounting for climate change impacts in certain planning efforts; and (4) evaluates the extent to which DOD incorporates adaptation into its infrastructure-investment efforts.GAO reviewed DOD documents on climate change, infrastructure planning, and funding processes; interviewed cognizant officials; and visited or contacted a nongeneralizable sample of 15 sites in various regions and from each military department. GAO recommends that DOD develop a plan and milestones for completing climate change vulnerability assessments of installations; provide further information to installation planners, clarifying actions that should be taken to account for climate change in planning documents; and clarify the processes used to compare military construction projects for funding, to include consideration of potential climate change impacts. DOD concurred with GAO's recommendations and explained how they will be implemented.

The detection of potential long-term changes in historical storm statistics and storm surges plays a vitally important role for protecting coastal communities. In the absence of long homogeneous wind records, the authors present a novel, independent, and homogeneous storm surge record based on water level observations in the North Sea since 1843. Storm surges are characterized by considerable interannual-to-decadal variability linked to large-scale atmospheric circulation patterns. Time periods of increased storm surge levels prevailed in the late nineteenth and twentieth centuries without any evidence for significant long-term trends. This contradicts with recent findings based on reanalysis data, which suggest increasing storminess in the region since the late nineteenth century. The authors compare the wind and pressure fields from the Twentieth-Century Reanalysis (20CRv2) with the storm surge record by applying state-of-the-art empirical wind surge formulas. The comparison reveals that the reanalysis is a valuable tool that leads to good results over the past 100 yr; previously the statistical relationship fails, leaving significantly lower values in the upper percentiles of the predicted surge time series. These low values lead to significant upward trends over the entire investigation period, which are in turn supported by neither the storm surge record nor an independent circulation index based on homogeneous pressure readings. The authors therefore suggest that these differences are related to higher uncertainties in the earlier years of the 20CRv2 over the North Sea region., QC 20140624

The incidence of major storm surges in the last decade have dramatically emphasized the immense destructive capabilities of extreme water level events, particularly when driven by severe tropical cyclones. Given this risk, it is vitally important that the exceedance probabilities of extreme water levels are accurately evaluated to inform risk-based flood and erosion management, engineering and for future land-use planning and to ensure the risk of catastrophic structural failures due to under-design or expensive wastes due to over-design are minimised. Australia has a long history of coastal flooding from tropical cyclones. Using a novel integration of two modeling techniques, this paper provides the first estimates of present day extreme water level exceedance probabilities around the whole coastline of Australia, and the first estimates that combine the influence of astronomical tides, storm surges generated by both extra-tropical and tropical cyclones, and seasonal and inter-annual variations in mean sea level. Initially, an analysis of tide gauge records has been used to assess the characteristics of tropical cyclone-induced surges around Australia. However, given the dearth (temporal and spatial) of information around much of the coastline, and therefore the inability of these gauge records to adequately describe the regional climatology, an observationally based stochastic tropical cyclone model has been developed to synthetically extend the tropical cyclone record to 10,000 years. Wind and pressure fields derived for these synthetically generated events have then been used to drive a hydrodynamic model of the Australian continental shelf region with annual maximum water levels extracted to estimate exceedance probabilities around the coastline. To validate this methodology, selected historic storm surge events have been simulated and resultant storm surges compared with gauge records. Tropical cyclone induced exceedance probabilities have been combined with e

The occurrence of extreme water levels along low-lying, highly populated and/or developed coastlines can lead to considerable loss of life and billions of dollars of damage to coastal infrastructure. Therefore it is vitally important that the exceedance probabilities of extreme water levels are accurately evaluated to inform risk-based flood management, engineering and future land-use planning. This ensures the risk of catastrophic structural failures due to under-design or expensive wastes due to over-design are minimised. This paper estimates for the first time present day extreme water level exceedence probabilities around the whole coastline of Australia. A high-resolution depth averaged hydrodynamic model has been configured for the Australian continental shelf region and has been forced with tidal levels from a global tidal model and meteorological fields from a global reanalysis to generate a 61-year hindcast of water levels. Output from this model has been successfully validated against measurements from 30 tide gauge sites. At each numeric coastal grid point, extreme value distributions have been fitted to the derived time series of annual maxima and the several largest water levels each year to estimate exceedence probabilities. This provides a reliable estimate of water level probabilities around southern Australia; a region mainly impacted by extra-tropical cyclones. However, as the meteorological forcing used only weakly includes the effects of tropical cyclones, extreme water level probabilities are underestimated around the western, northern and north-eastern Australian coastline. In a companion paper we build on the work presented here and more accurately include tropical cyclone-induced surges in the estimation of extreme water level. The multi-decadal hindcast generated here has been used primarily to estimate extreme water level exceedance probabilities but could be used more widely in the future for a variety of other research and practical appli

The hydrodynamics of estuaries are forced by the tides from the open sea and the river runoff from the catchment area. The hinterland is often low-lying and densely populated and must therefore be protected by dikes. Anthropogenic climate change poses new challenges to the coastal protection. However, changes in the geometry of the estuaries can have equally severe impacts on the deformation of a storm surge wave form when it propagates through the estuary. This affects the peak water levels and hence the design water levels. This contribution focuses on the influence of retention areas or forelands seaside of the main dike lines, which are protected by summer dikes against the less severe but more frequently occurring storm surges. This is shown at the example of a retention area in the Weser estuary, which has historically been the cite of a soccer stadium and thus hosts high values which stand in sharp contrast against the low safety level against flooding. The investigation is conducted with a 3D hydrodynamic numerical model which has previously been validated for the simulation of storm surges. The results show that even very small changes in the geometry of the estuary can have effects on design levels. This is even the case when they only regard the summer dike crests heights around retention areas and not their volume. Another important finding is that the geometry changes may have their maximum impacts quite far away from the specific river reach in which they are carried out. The results underline that for designing safe and reliable storm surge infrastructure, storm events should be studied in high resolution models which are able to resolve even small scale features such as summer dike lines.

The combination of the coarse temporal sampling by satellite altimeters in the deep ocean with the high temporal sampling at sparsely located tide gauges along the coast has been used to improve the forecast of high water for the North Sea along the Danish Coast and for the northeast coast of Australia. For both locations we have tried to investigate the possibilities and limitations of the use of satellite altimetry to capture high frequency signals (surges) using data from the past 20 years. The two regions are chosen to represent extra-tropical and tropical storm surge conditions. We have selected several representative high water events on the two continents based on tide gauge recordings and investigated the capability of satellite altimetry to capture these events in the sea surface height data. Due to the lack of recent surges in the North Sea we focused on general high water level and found that in the presence of two or more satellites we could capture more than 90% of the high water sea level events. In the Great Barrier Reef section of the northeast Australian coast, we have investigated several large tropical cyclones; one of these being Cyclone Larry, which hit the Queensland coast in March 2006 and caused both loss of lives as well as huge devastation. Here we demonstrate the importance of integrating tide gauges with satellite altimetry for forecasting high water at the city of Townsville in northeast Australia.

Lake St. Clair is a shallow water body located between Lake Huron and Lake Erie in the Great Lakes complex with coastline in both US and Canada. The numerical modeling of waves and water levels was performed to capture storm conditions along the US coastline. The methodology presented in Jensen et al. (2012) for Lake Michigan was followed for the majority of the project. The NOAA/NCEP Climate Forecast System Reanalysis wind fields were adjusted for marine exposure wind speeds. The WAM wave model was validated and applied for production of all wind generated wave results, including ice when applicable. The ADCIRC model was forced with wind fields, flow rates at the St. Clair River boundary, and water levels at the Detroit River boundary and validated to water levels at St. Clair Shores and Windmill Point. The ADCIRC model was tightly coupled with four near-shore Full-Plane STWAVE model grids using CSTORM-MS. The results show good agreement between all validation data sets, and low errors in the production storms with which data was available. In total, 145 storm events were run with the full numerical system to quantify the water level response to extreme events In Lake St. Clair., Sponsored in part by FEMA.

The Federal Emergency Management Agency (FEMA), Region III office, has initiated a study to update the coastal storm surge elevations within the states of Virginia, Maryland, and Delaware, and the District of Columbia. The area includes the Atlantic Ocean, the Chesapeake Bay, including its tributaries, and the Delaware Bay. This effort is one of the most extensive coastal storm surge analyses to date, encompassing coastal floodplains in three states and including the largest estuary in the world. The study will replace outdated coastal storm surge stillwater elevations for all Flood Insurance Studies in the study area, and serve as the basis for new coastal hazard analysis and ultimately updated Flood Insurance Rate Maps (FIRMs). Study efforts were initiated in August of 2008, and are expected to conclude in 2012. The storm surge study considers both tropical storms and extratropical cyclones for determination of return period storm surge elevations. The historical record of events in the region has been used to reconstruct wind and pressure fields for significant extratropical cyclone events and to develop a synthetic suite of tropical storm tracks and associated parameters to drive the models. This will support the statistical analysis of storm surge return period elevations. This report, the third of three reports comprising the required Submittal 1 documentation, describes development of the wind and pressure fields required for FEMA Region III storm surge modeling., The original document contains color images.

This study aims to assess potential future damage of climate change induced flood on Hong Kong and Pearl River Delta (PRD). The estimation is focus on the order of magnitude. Based on the statistical analysis of global flood impact data and local sea level record, three types of damage are predicted in this study, namely, deaths, displacements and economic loss. A global-national-regional assessment approach has established by quantitatively measure flood exposure and vulnerability. The analysis of global data demonstrates that damages are exponentially increased with flood exposure level (defined as ‘flood magnitude’ in this study). Furthermore, the increasing rate (referred to as ‘flood vulnerability indices’) at the national level is partly related to its level of development, as represented by its world development indicators (WDIs). Accordingly, regional vulnerability can be inferred by comparing the correlated indicators with countries, thus project the future losses. By studying reports from the Federal Emergency Management Agency (FEMA), this study also estimates the flood recovery durations from US experiences. The analysis concludes that with sea level rise 40 to 75 cm by 2100, a current 20 to more than 100 year event would become an annual storm surge event. In the absence of adaptation, the potential losses would be significant. For instance, by 2100, an expected loss of an annual storm surge event in Hong Kong could lead to 20 to 60 deaths, 5 to 200 thousand people displaced, and USD $300 million to more than USD $7 billion economic losses in total. In the PRD, the same event could lead to 100 to more than 700 deaths, 2 to 20 million people displaced, and USD $100 million to more than USD $3 billion in economic losses. Moreover, this region needs several months to recover from the future annual flood event. Our results call for immediate implementation of adaptation measures to help minimize the potential impacts.

Several scientists are calculating that Odessa City (on the Odessa bay coast) have 600 years from founding according to chronist Jan Dlugosh one source in 1418. At the same time, the Ancient City absent on different maps, books and church’s chronics of Europe. Real official date of Odessa foundation is 1795, after Russia military occupying of the coastal territory near the Black Sea. In XIV-XV centuries period, environment structure and regime not permitted by the big sea-port to locate and work. The Ancient City haven’t any connections with Odessa City that is modern big sea-port and locate in other site of the Black Sea coast., В современной украинской исторической литературе содержатся попытки доказать, что в XIV-XV веках в Одесском заливе находился крупный торговый порт, а при нем – большой город. Анализ физико-географических условий Одесского залива показал, что это невозможно. Прежде всего, по причине крайне малых глубин возле берега. Неблагоприятной была система течений, морских волн, ледового режима. Высокой была подвижность наносов, море часто прорывалось в лиманы и образовывало довольно глубокие прорвы. Крупные оползни не позволяли вести строительство при тогдашнем уровне техники. Достаточные источники воды и топлива отсутствовали. Нависала постоянная угроза нападения кочевников на открытом пространстве засушливой степи. Ни на одной карте того времени не обозначен данный пункт как крупный торговый порт. Сумма всех этих условий делала невозможным существование достаточно крупного населенного пункта и порта на месте современной Одессы., В давніх документах Епохи Відродження немає обґрунтованого свідоцтва про існування «Качибея» – попередника Одеси на берегах Одеської затоки в період XIV-XV століть. Серед деяких дослідників існує думка, що в ті часи в Одеській затоці було велике місто і при ньому – торгівельний порт. Аналіз фізико-географічних умов Одеської затоки протягом Епохи Відродження показав неможливість існування міста та порту. За причинами, по-перше, рельєфу та мілинності прибережного дна, активності зсувних берегів, рухомості наносів. По-друге, несприятливою була система хвиль, вітрів, течій, рівня води, льодового режиму. Море кожного року проривало піщаний бар’єр пересипів Хаджибейського та Куяльницкого лиманів та з’єднувалося із ним. По-третє, не було місцевих ресурсів води, харчів, палива. Велику загрозу створювали кочові ногайські племена, войовничі, іншої віри, союзники татар та турків. Цей порт не був показаний на навігаційних картах того часу. Ніяких вістей та чуток про «Качибей» не було від 1420 р. до 1809 р., коли краєзнавці ознайомилися із записами Яна Длугоша.

This study aims to assess potential future damage of climate change induced flood on Hong Kong and Pearl River Delta (PRD). The estimation is focus on the order of magnitude. Based on the statistical analysis of global flood impact data and local sea level record, three types of damage are predicted in this study, namely, deaths, displacements and economic loss. A global-national-regional assessment approach has established by quantitatively measure flood exposure and vulnerability. The analysis of global data demonstrates that damages are exponentially increased with flood exposure level (defined as ‘flood magnitude’ in this study). Furthermore, the increasing rate (referred to as ‘flood vulnerability indices’) at the national level is partly related to its level of development, as represented by its world development indicators (WDIs). Accordingly, regional vulnerability can be inferred by comparing the correlated indicators with countries, thus project the future losses. By studying reports from the Federal Emergency Management Agency (FEMA), this study also estimates the flood recovery durations from US experiences. The analysis concludes that with sea level rise 40 to 75 cm by 2100, a current 20 to more than 100 year event would become an annual storm surge event. In the absence of adaptation, the potential losses would be significant. For instance, by 2100, an expected loss of an annual storm surge event in Hong Kong could lead to 20 to 60 deaths, 5 to 200 thousand people displaced, and USD $300 million to more than USD $7 billion economic losses in total. In the PRD, the same event could lead to 100 to more than 700 deaths, 2 to 20 million people displaced, and USD $100 million to more than USD $3 billion in economic losses. Moreover, this region needs several months to recover from the future annual flood event. Our results call for immediate implementation of adaptation measures to help minimize the potential impacts.

Author Posting. © American Geophysical Union, 2013. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 118 (2013): 2685–2701, doi:10.1002/jgrc.20207., Hurricane Bob moved up the U.S. east coast and crossed over southern New England and the Gulf of Maine [with peak marine winds up to 54 m/s (100 mph)] on 19–20 August 1991, causing significant damage along the coast and shelf. A 3-D fully wave-current-coupled finite-volume community ocean model system was developed and applied to simulate and examine the coastal ocean responses to Hurricane Bob. Results from process study-oriented experiments showed that the impact of wave-current interaction on surge elevation varied in space and time, more significant over the shelf than inside the inner bays. While sea level change along the coast was mainly driven by the water flux controlled by barotropic dynamics and the vertically integrated highest water transports were essentially the same for cases with and without water stratification, the hurricane-induced wave-current interaction could generate strong vertical current shear in the stratified areas, leading to a strong offshore transport near the bottom and vertical turbulent mixing over the continental shelf. Stratification could also result in a significant difference of water currents around islands where the water is not vertically well mixed., This work was supported by the MIT Sea Grant College Program through grant 2012-R/RC-127 and the NOAA NERACOOS Program funds for NECOFS. The development of the FVCOM system has been supported by the NSF Ocean Sciences Division through grants OCE-0234545, OCE-0227679, OCE-0606928, and OCE- 0712903 and the NSF Office of Polar Programs-Arctic Sciences Division through grants ARC0712903, ARC0732084, ARC0804029, and ARC1203393. C.C.’s contribution was also supported by Shanghai Ocean University International Cooperation Program (A-2302-11-0003), the Program of Science and Technology Commission of Shanghai Municipality (09320503700), and the Leading Academic Discipline Project of Shanghai Municipal Education Commission (J50702)., 2013-11-30

Author Posting. © American Geophysical Union, 2013. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 118 (2013): 2685–2701, doi:10.1002/jgrc.20207., Hurricane Bob moved up the U.S. east coast and crossed over southern New England and the Gulf of Maine [with peak marine winds up to 54 m/s (100 mph)] on 19–20 August 1991, causing significant damage along the coast and shelf. A 3-D fully wave-current-coupled finite-volume community ocean model system was developed and applied to simulate and examine the coastal ocean responses to Hurricane Bob. Results from process study-oriented experiments showed that the impact of wave-current interaction on surge elevation varied in space and time, more significant over the shelf than inside the inner bays. While sea level change along the coast was mainly driven by the water flux controlled by barotropic dynamics and the vertically integrated highest water transports were essentially the same for cases with and without water stratification, the hurricane-induced wave-current interaction could generate strong vertical current shear in the stratified areas, leading to a strong offshore transport near the bottom and vertical turbulent mixing over the continental shelf. Stratification could also result in a significant difference of water currents around islands where the water is not vertically well mixed., This work was supported by the MIT Sea Grant College Program through grant 2012-R/RC-127 and the NOAA NERACOOS Program funds for NECOFS. The development of the FVCOM system has been supported by the NSF Ocean Sciences Division through grants OCE-0234545, OCE-0227679, OCE-0606928, and OCE- 0712903 and the NSF Office of Polar Programs-Arctic Sciences Division through grants ARC0712903, ARC0732084, ARC0804029, and ARC1203393. C.C.’s contribution was also supported by Shanghai Ocean University International Cooperation Program (A-2302-11-0003), the Program of Science and Technology Commission of Shanghai Municipality (09320503700), and the Leading Academic Discipline Project of Shanghai Municipal Education Commission (J50702)., 2013-11-30

This study aims to assess potential future damage of climate change induced flood on Hong Kong and Pearl River Delta (PRD). The estimation is focus on the order of magnitude. Based on the statistical analysis of global flood impact data and local sea level record, three types of damage are predicted in this study, namely, deaths, displacements and economic loss. A global-national-regional assessment approach has established by quantitatively measure flood exposure and vulnerability. The analysis of global data demonstrates that damages are exponentially increased with flood exposure level (defined as ‘flood magnitude’ in this study). Furthermore, the increasing rate (referred to as ‘flood vulnerability indices’) at the national level is partly related to its level of development, as represented by its world development indicators (WDIs). Accordingly, regional vulnerability can be inferred by comparing the correlated indicators with countries, thus project the future losses. By studying reports from the Federal Emergency Management Agency (FEMA), this study also estimates the flood recovery durations from US experiences. The analysis concludes that with sea level rise 40 to 75 cm by 2100, a current 20 to more than 100 year event would become an annual storm surge event. In the absence of adaptation, the potential losses would be significant. For instance, by 2100, an expected loss of an annual storm surge event in Hong Kong could lead to 20 to 60 deaths, 5 to 200 thousand people displaced, and USD $300 million to more than USD $7 billion economic losses in total. In the PRD, the same event could lead to 100 to more than 700 deaths, 2 to 20 million people displaced, and USD $100 million to more than USD $3 billion in economic losses. Moreover, this region needs several months to recover from the future annual flood event. Our results call for immediate implementation of adaptation measures to help minimize the potential impacts.

The present recommendations for dune removal or dune retreat on the Great Lakes for Federal Emergency Management Agency (FEMA) flood mapping purposes are based on a simple geometric method as outlined in FEMA (2009). The simple procedure establishes a relationship between dune survival and storm intensity. The method was adopted several decades ago when numerical models were inadequate for predicting beach profile change and dune retreat. Herein, a robust and efficient model for predicting nearshore waves, circulation, water levels, sediment transport, and nearshore morphology is provided as an option in replacing the geometric model. The numerical model is compared with results from the existing FEMA guidelines for storm-induced beach change at three sites with different nearshore characteristics. A typical storm with detailed modeled hydrodynamics has been used to provide a basis for boundary conditions, and use is made of scaling to approximate a variation in intensity. A change in water levels is also included in the analysis through a reasonable fluctuation of the static lake level. In general, the methodology in FEMA guidelines computes much larger eroded volume than the numerical model predictions. Additionally, the dependence of the volumes on recurrence interval is determined to be much stronger utilizing the FEMA method. Generalizations are difficult, however, and the predicted volume from the numerical model was larger for some cases of moderate storm intensity. The numerically predicted results were shown to depend on the details of both the subaqueous profiles and dune configuration, and simple universal predictions may suffer gross error., Great Lakes Coastal Flood Study, 2012 Federal Inter-Agency Initiative. The original document contains color images.

This paper presents a new approach of applying numerical methods to model storm processes. A storm empirical track technique is utilized to simulate the full tracks of hurricanes, starting with their initial points over the sea and ending with their landfall locations or final dissipations. The theoretical framework was first described in the literature by Vickery et al. (2000) and is extended in this study by introducing a new formula and several substantial adjustments. The results show acceptable accuracy, even if the input data are for a short period. For the Vietnam area, the research successfully generates a large database of synthetic storm tracks on the basis of a limited historical track record and a local climatological variable (i.e. sea surface temperature). The model is evaluated through the comparisons between the key storm statistics derived from the observed and simulated data over the entire research area (i.e. the South China Sea). In addition, some possible applications of this method to coastal structure design and coastal risk assessment are proposed., Hydraulic Engineering, Civil Engineering and Geosciences

Coastal areas are dynamic environments that are home to billions of people worldwide and provide areas of unique natural importance. As such, coastal change is of considerable local and global interest, not only within the geological realm, but also in terms of socioeconomic and biodiversity impacts. An accurate understanding of how changes in relative sea level, geological processes and extreme events, such as storms and tsunamis, have interacted to shape and change the Earth’s coastlines over millennia is fundamental to future projections of coastal change. On the basis of this, researchers in these, and various other aspects of coastal change were brought together in late 2010 at the University of Hong Kong for the first meeting of International Geoscience Program Project 588 (IGCP588) e Preparing for Coastal Change. This special issue showcases some of the results presented at this meeting.

This paper presents a new approach of applying numerical methods to model storm processes. A storm empirical track technique is utilized to simulate the full tracks of hurricanes, starting with their initial points over the sea and ending with their landfall locations or final dissipations. The theoretical framework was first described in the literature by Vickery et al. (2000) and is extended in this study by introducing a new formula and several substantial adjustments. The results show acceptable accuracy, even if the input data are for a short period. For the Vietnam area, the research successfully generates a large database of synthetic storm tracks on the basis of a limited historical track record and a local climatological variable (i.e. sea surface temperature). The model is evaluated through the comparisons between the key storm statistics derived from the observed and simulated data over the entire research area (i.e. the South China Sea). In addition, some possible applications of this method to coastal structure design and coastal risk assessment are proposed., Hydraulic Engineering, Civil Engineering and Geosciences

Rising global sea level increases the vulnerability of coastal regions to storm surge flooding. The impact of extreme high waters resulting from the combination of tidal oscillations and changes in mean sea level and in storm surges during the 21st century has been explored in the Bizkaian coast (northern Spain). Mean sea level variations due to temperature changes were estimated from an ensemble mean of global atmosphere-ocean general circulation models in the Bay of Biscay under A1B and A2 climate change scenarios. Changes in the frequency and intensity of storm surges were obtained from the output of a barotropic regional ocean model forced by greenhouse gas concentrations during 2000−2100. The storm surge model was calibrated using available tide gauge observations. Based on the above estimations, return levels of total sea level extremes are expected to increase by up to 40 cm with respect to present-day values. The likely impacts of resulting floods on coastal and estuarine habitats of the Bizkaian coast were assessed applying the return levels to a high precision light detection and ranging (LiDAR) based Digital Terrain Model. Results show that during the second half of the 21st century up to 202 ha are under risk of flooding, of which 50% correspond to urbanized land including industrial and residential areas. This represents a more than 3-fold increase compared to the area at risk from present sea level extremes. This study provides insight into both regional sea level variability and local floodrisks, and thus provides inputs for the formulation of effective mid-term adaptation measures to sea level extremes.

Hurricane Gustav (2008) made landfall in southern Louisiana on 1 September 2008 with its eye never closer than 75 km to New Orleans, but its waves and storm surge threatened to flood the city. Easterly tropical-storm- strength winds impacted the region east of the Mississippi River for 12-15 h, allowing for early surge to develop up to 3.5 m there and enter the river and the city's navigation canals. During landfall, winds shifted from easterly to southerly, resulting in late surge development and propagation over more than 70 km of marshes on the river's west bank, over more than 40 km of Caernarvon marsh on the east bank, and into Lake Pontchartrain to the north. Wind waves with estimated significant heights of 15 m developed in the deep Gulf of Mexico but were reduced in size once they reached the continental shelf. The barrier islands further dissipated the waves, and locally generated seas existed behind these effective breaking zones. The hardening and innovative deployment of gauges since Hurricane Katrina (2005) resulted in a wealth of measured data for Gustav. A total of 39 wind wave time histories, 362 water level time histories, and 82 high water marks were available to describe the event. Computational models -- including a structured-mesh deepwater wave model (WAM) and a nearshore steady-state wave (STWAVE) model, as well as an unstructured-mesh simulating waves nearshore (SWAN) wave model and an advanced circulation (ADCIRC)model -- resolve the region with unprecedented levels of detail, with an unstructured mesh spacing of 100-200 m in the wave-breaking zones and 20-50 m in the small-scale channels. Data-assimilated winds were applied using NOAA's Hurricane Research Division Wind Analysis System (H*Wind) and Interactive Objective Kinematic Analysis (IOKA) procedures. Wave and surge computations from these models are validated comprehensively at the measurement locations ranging from the deep Gulf of Mexico and along the coast of southern Louisiana., Published in Monthly Weather Review, v139 p2488-2522, Aug 2011. Prepared in collaboration with Coastal and Hydraulics Laboratory, U.S. Army Engineer Research and Development Center, Vicksburg, Mississippi; Faculty of Civil Engineering and Geosciences, Delft University of Technology, Delft, Netherlands; Institute for Computational Engineering and Sciences, University of Texas at Austin, Austin, Texas; Institute of Marine Sciences, University of North Carolina at Chapel Hill, Morehead City, North Carolina; NOAA/Atlantic Oceanographic and Meteorological Laboratory/Hurricane Research Division, Miami, Florida; Oceanweather, Inc., Cos Cob, Connecticut; Coastal Studies Institute, Louisiana State University, Baton Rouge, Louisiana; and New Orleans District, U.S. Army Corps of Engineers, New Orleans, Louisiana. The original document contains color images.

The Federal Emergency Management Agency, Region III office, has initiated a study to update the coastal storm surge elevations within the states of Virginia, Maryland, and Delaware, and the District of Columbia including the Atlantic Ocean, Chesapeake Bay and its tributaries, and the Delaware Bay. This effort is one of the most extensive coastal storm surge analyses to date, encompassing coastal floodplains in three states and including the largest estuary in the world. The study will replace outdated coastal storm surge stillwater elevations for all Flood Insurance Studies in the study area, and serve as the basis for new coastal hazard analysis and ultimately updated Flood Insurance Rate Maps (FIRMs). Study efforts were initiated in August of 2008, and are expected to conclude in 2010. The storm surge study will utilize the Advanced Circulation Model for Oceanic, Coastal and Estuarine Waters (ADCIRC) for simulation of 2-dimensional hydraulics. ADCIRC will be coupled with 2-dimensional wave models to calculate the combined effects of surge and wind-induced waves. A seamless modeling grid was developed to support the storm surge modeling efforts. This report, the first of three reports comprising the required Submittal 1 documentation, provides a detailed overview of the construction of the Digital Elevation Model, modeling mesh, and the development of an integrated computational system for FEMA Region III storm surge modeling., The original document contains color images.

Extreme sea levels – storm-generated surges and falls - on the Polish coast are usually the effects of three components: the volume of water in the southern Baltic (the initial level preceding a given extreme situation), the action of tangential wind stresses in the area (wind directions: whether shore- or seaward; wind velocities; and wind action duration), and the sea surface deformation produced by deep, mesoscale baric lows moving rapidly over the southern and central Baltic that generate the so-called baric wave. Among these factors, the baric wave is particularly important for, i.e. the water cushion underneath the baric depression, moving along the actual atmospheric pressure system over the sea surface.