Developing an early warning system for storm surge inundation in the Philippines

Science.gov (United States)

Tablazon, J.; Caro, C. V.; Lagmay, A. M. F.; Briones, J. B. L.; Dasallas, L.; Lapidez, J. P.; Santiago, J.; Suarez, J. K.; Ladiero, C.; Gonzalo, L. A.; Mungcal, M. T. F.; Malano, V.

2014-10-01

A storm surge is the sudden rise of sea water generated by an approaching storm, over and above the astronomical tides. This event imposes a major threat in the Philippine coastal areas, as manifested by Typhoon Haiyan on 8 November 2013 where more than 6000 people lost their lives. It has become evident that the need to develop an early warning system for storm surges is of utmost importance. To provide forecasts of the possible storm surge heights of an approaching typhoon, the Nationwide Operational Assessment of Hazards under the Department of Science and Technology (DOST-Project NOAH) simulated historical tropical cyclones that entered the Philippine Area of Responsibility. Bathymetric data, storm track, central atmospheric pressure, and maximum wind speed were used as parameters for the Japan Meteorological Agency Storm Surge Model. The researchers calculated the frequency distribution of maximum storm surge heights of all typhoons under a specific Public Storm Warning Signal (PSWS) that passed through a particular coastal area. This determines the storm surge height corresponding to a given probability of occurrence. The storm surge heights from the model were added to the maximum astronomical tide data from WXTide software. The team then created maps of probable area inundation and flood levels of storm surges along coastal areas for a specific PSWS using the results of the frequency distribution. These maps were developed from the time series data of the storm tide at 10 min intervals of all observation points in the Philippines. This information will be beneficial in developing early warnings systems, static maps, disaster mitigation and preparedness plans, vulnerability assessments, risk-sensitive land use plans, shoreline defense efforts, and coastal protection measures. Moreover, these will support the local government units' mandate to raise public awareness, disseminate information about storm surge hazards, and implement appropriate counter

Vulnerability assessment of storm surges in the coastal area of Guangdong Province

Directory of Open Access Journals (Sweden)

K. Li

2011-07-01

Full Text Available Being bordered by the South China Sea and with long coastline, the coastal zone of Guangdong Province is often under severe risk of storm surges, as one of a few regions in China which is seriously threatened by storm surges. This article systematically analyzes the vulnerability factors of storm surges in the coastal area of Guangdong (from Yangjing to Shanwei. Five vulnerability assessment indicators of hazard-bearing bodies are proposed, which are social economic index, land use index, eco-environmental index, coastal construction index, and disaster-bearing capability index. Then storm surge vulnerability assessment index system in the coastal area of Guangdong is established. Additionally, the international general mode about coastal vulnerability assessment is improved, and the vulnerability evolution model of storm surges in the coastal area of Guangdong is constructed. Using ArcGIS, the vulnerability zoning map of storm surges in the study region is drawn. Results show that there is the highest degree of storm surge vulnerability in Zhuhai, Panyu, and Taishan; second in Zhongshan, Dongguan, Huiyang, and Haifeng; third in Jiangmen, Shanwei, Yangjiang, and Yangdong; fourth in Baoan, Kaiping, and Enping; and lowest in Guangzhou, Shunde, Shenzhen, and Longgang. This study on the risk of storm surges in these coastal cities can guide the land use of coastal cities in the future, and provide scientific advice for the government to prevent and mitigate the storm surge disasters. It has important theoretical and practical significance.

Adaptive mesh refinement for storm surge

KAUST Repository

Mandli, Kyle T.; Dawson, Clint N.

2014-01-01

An approach to utilizing adaptive mesh refinement algorithms for storm surge modeling is proposed. Currently numerical models exist that can resolve the details of coastal regions but are often too costly to be run in an ensemble forecasting framework without significant computing resources. The application of adaptive mesh refinement algorithms substantially lowers the computational cost of a storm surge model run while retaining much of the desired coastal resolution. The approach presented is implemented in the GeoClaw framework and compared to ADCIRC for Hurricane Ike along with observed tide gauge data and the computational cost of each model run. © 2014 Elsevier Ltd.

Adaptive mesh refinement for storm surge

KAUST Repository

Mandli, Kyle T.

2014-03-01

An approach to utilizing adaptive mesh refinement algorithms for storm surge modeling is proposed. Currently numerical models exist that can resolve the details of coastal regions but are often too costly to be run in an ensemble forecasting framework without significant computing resources. The application of adaptive mesh refinement algorithms substantially lowers the computational cost of a storm surge model run while retaining much of the desired coastal resolution. The approach presented is implemented in the GeoClaw framework and compared to ADCIRC for Hurricane Ike along with observed tide gauge data and the computational cost of each model run. © 2014 Elsevier Ltd.

Hurricane storm surge and amphibian communities in coastal wetlands of northwestern Florida

Science.gov (United States)

Gunzburger, M.S.; Hughes, W.B.; Barichivich, W.J.; Staiger, J.S.

2010-01-01

Isolated wetlands in the Southeastern United States are dynamic habitats subject to fluctuating environmental conditions. Wetlands located near marine environments are subject to alterations in water chemistry due to storm surge during hurricanes. The objective of our study was to evaluate the effect of storm surge overwash on wetland amphibian communities. Thirty-two wetlands in northwestern Florida were sampled over a 45-month period to assess amphibian species richness and water chemistry. During this study, seven wetlands were overwashed by storm surge from Hurricane Dennis which made landfall 10 July 2005 in the Florida panhandle. This event allowed us to evaluate the effect of storm surge overwash on water chemistry and amphibian communities of the wetlands. Specific conductance across all wetlands was low pre-storm (marine habitats are resistant to the effects of storm surge overwash. ?? 2010 Springer Science+Business Media B.V.

Monitoring Inland Storm Surge and Flooding from Hurricane Rita

Science.gov (United States)

McGee, Benton D.; Tollett, Roland W.; Mason, Jr., Robert R.

2006-01-01

Pressure transducers (sensors) and high-water marks were used to document the inland water levels related to storm surge generated by Hurricane Rita in southwestern Louisiana and southeastern Texas. On September 22-23, 2005, an experimental monitoring network of sensors was deployed at 33 sites over an area of about 4,000 square miles to record the timing, extent, and magnitude of inland hurricane storm surge and coastal flooding. Sensors were programmed to record date and time, temperature, and barometric or water pressure. Water pressure was corrected for changes in barometric pressure and salinity. Elevation surveys using global-positioning systems and differential levels were used to relate all storm-surge water-level data, reference marks, benchmarks, sensor measuring points, and high-water marks to the North American Vertical Datum of 1988 (NAVD 88). The resulting data indicated that storm-surge water levels over 14 feet above NAVD 88 occurred at three locations, and rates of water-level rise greater than 5 feet per hour occurred at three locations near the Louisiana coast.

Effect of Tide Elevation on Extratropical Storm Surge in Northwest Europe

Science.gov (United States)

Keshtpoor, M.; Carnacina, I.; Yablonsky, R. M.

2016-12-01

Extratropical cyclones (ETCs) are the major storm surge-generating meteorological events in northwest Europe. The total water level increase induced by these ETCs is significantly influenced by the local tidal range, which exceeds 8 meters along the southwestern UK coastline. In particular, a surge-generating ETC during high tide may put coastal assets and infrastructure in risk. Also, during low tide, the risk of surge induced by extreme ETC events is diminished. Here, the effect of tidal elevation on storm surge is investigated at 196 tide gauges in northwest Europe. A numerical, hydrodynamic model was developed using Delft3D-FM framework to simulate the coastal hydrodynamics during ETCs. Then, 1750 historical events were simulated to investigate the pattern of coastal inundation. Results suggest that in areas with a large tidal range ( 8 meters) and during the time period surrounding high or low tide, the pattern of coastal hydrodynamics is governed by tide and not storm surge. This result is most evident near the English Channel and Bristol Channel, where low frequency maximum water levels are observed when storm surge is combined with high tide. In contrast, near the tidal phase reversal, coastal hydrodynamics responds primarily to the storm surge, and low frequency maximum water elevation largely depends on the surge. In the areas with a small tidal range, ETC strength determines the pattern of coastal inundation.

Comparison of two recent storm surge events based on results of field surveys

Science.gov (United States)

Nakamura, Ryota; Shibayama, Tomoya; Mikami, Takahito; Esteban, Miguel; Takagi, Hiroshi; Maell, Martin; Iwamoto, Takumu

2017-10-01

This paper compares two different types of storm surge disaster based on field surveys. Two cases: a severe storm surge flood with its height of over 5 m due to Typhoon Haiyan (2013) in Philippine, and inundation of storm surge around Nemuro city in Hokkaido of Japan with its maximum surge height of 2.8 m caused by extra-tropical cyclone are taken as examples. For the case of the Typhoon Haiyan, buildings located in coastal region were severely affected due to a rapidly increase in ocean surface. The non-engineering buildings were partially or completely destroyed due to their debris transported to an inner bay region. In fact, several previous reports indicated two unique features, bore-like wave and remarkably high speed currents. These characteristics of the storm surge may contribute to a wide-spread corruption for the buildings around the affected region. Furthermore, in the region where the surge height was nearly 3 m, the wooden houses were completely or partially destroyed. On the other hand, in Nemuro city, a degree of suffering in human and facility caused by the storm surge is minor. There was almost no partially destroyed residential houses even though the height of storm surge reached nearly 2.8 m. An observation in the tide station in Nemuro indicated that this was a usual type of storm surge, which showed a gradual increase of sea level height in several hours without possessing the unique characteristics like Typhoon Haiyan. As a result, not only the height of storm surge but also the robustness of the buildings and characteristics of storm surge, such as bore like wave and strong currents, determined the existent of devastation in coastal regions.

A numerical storm surge forecast model with Kalman filter

Institute of Scientific and Technical Information of China (English)

Yu Fujiang; Zhang Zhanhai; Lin Yihua

2001-01-01

Kalman filter data assimilation technique is incorporated into a standard two-dimensional linear storm surge model. Imperfect model equation and imperfect meteorological forcimg are accounted for by adding noise terms to the momentum equations. The deterministic model output is corrected by using the available tidal gauge station data. The stationary Kalman filter algorithm for the model domain is calculated by an iterative procedure using specified information on the inaccuracies in the momentum equations and specified error information for the observations. An application to a real storm surge that occurred in the summer of 1956 in the East China Sea is performed by means of this data assimilation technique. The result shows that Kalman filter is useful for storm surge forecast and hindcast.

Monitoring Hurricane Rita Inland Storm Surge: Chapter 7J in Science and the storms-the USGS response to the hurricanes of 2005

Science.gov (United States)

McGee, Benton D.; Tollett, Roland W.; Goree, Burl B.

2007-01-01

Pressure transducers (sensors) are accurate, reliable, and cost-effective tools to measure and record the magnitude, extent, and timing of hurricane storm surge. Sensors record storm-surge peaks more accurately and reliably than do high-water marks. Data collected by sensors may be used in storm-surge models to estimate when, where, and to what degree stormsurge flooding will occur during future storm-surge events and to calibrate and verify stormsurge models, resulting in a better understanding of the dynamics of storm surge.

The value of wetlands in protecting southeast louisiana from hurricane storm surges.

Science.gov (United States)

Barbier, Edward B; Georgiou, Ioannis Y; Enchelmeyer, Brian; Reed, Denise J

2013-01-01

The Indian Ocean tsunami in 2004 and Hurricanes Katrina and Rita in 2005 have spurred global interest in the role of coastal wetlands and vegetation in reducing storm surge and flood damages. Evidence that coastal wetlands reduce storm surge and attenuate waves is often cited in support of restoring Gulf Coast wetlands to protect coastal communities and property from hurricane damage. Yet interdisciplinary studies combining hydrodynamic and economic analysis to explore this relationship for temperate marshes in the Gulf are lacking. By combining hydrodynamic analysis of simulated hurricane storm surges and economic valuation of expected property damages, we show that the presence of coastal marshes and their vegetation has a demonstrable effect on reducing storm surge levels, thus generating significant values in terms of protecting property in southeast Louisiana. Simulations for four storms along a sea to land transect show that surge levels decline with wetland continuity and vegetation roughness. Regressions confirm that wetland continuity and vegetation along the transect are effective in reducing storm surge levels. A 0.1 increase in wetland continuity per meter reduces property damages for the average affected area analyzed in southeast Louisiana, which includes New Orleans, by $99-$133, and a 0.001 increase in vegetation roughness decreases damages by $24-$43. These reduced damages are equivalent to saving 3 to 5 and 1 to 2 properties per storm for the average area, respectively.

Using Satellite Altimetry to Calibrate the Simulation of Typhoon Seth Storm Surge off Southeast China

Directory of Open Access Journals (Sweden)

Xiaohui Li

2018-04-01

Full Text Available Satellite altimeters can capture storm surges generated by typhoons and tropical storms, if the satellite flies over at the right time. In this study, we show TOPEX/Poseidon altimeter-observed storm surge features off Southeast China on 10 October 1994 during Typhoon Seth. We then use a three-dimensional, barotropic, finite-volume community ocean model (FVCOM to simulate storm surges. An innovative aspect is that satellite data are used to calibrate the storm surge model to improve model performance, by adjusting model wind forcing fields (the National Center for Environment Prediction (NCEP reanalysis product in reference to the typhoon best-track data. The calibration reduces the along-track root-mean-square (RMS difference between model and altimetric data from 0.15 to 0.10 m. It also reduces the RMS temporal difference from 0.21 to 0.18 m between the model results and independent tide-gauge data at Xiamen. In particular, the calibrated model produces a peak storm surge of 1.01 m at 6:00 10 October 1994 at Xiamen, agreeing with tide-gauge data; while the peak storm surge with the NCEP forcing is 0.71 m only. We further show that the interaction between storm surges and astronomical tides contributes to the peak storm surge by 34% and that the storm surge propagates southwestward as a coastally-trapped Kelvin wave.

Evaluation of Loss Due to Storm Surge Disasters in China Based on Econometric Model Groups.

Science.gov (United States)

Jin, Xue; Shi, Xiaoxia; Gao, Jintian; Xu, Tongbin; Yin, Kedong

2018-03-27

Storm surge has become an important factor restricting the economic and social development of China's coastal regions. In order to improve the scientific judgment of future storm surge damage, a method of model groups is proposed to refine the evaluation of the loss due to storm surges. Due to the relative dispersion and poor regularity of the natural property data (login center air pressure, maximum wind speed, maximum storm water, super warning water level, etc.), storm surge disaster is divided based on eight kinds of storm surge disaster grade division methods combined with storm surge water, hypervigilance tide level, and disaster loss. The storm surge disaster loss measurement model groups consist of eight equations, and six major modules are constructed: storm surge disaster in agricultural loss, fishery loss, human resource loss, engineering facility loss, living facility loss, and direct economic loss. Finally, the support vector machine (SVM) model is used to evaluate the loss and the intra-sample prediction. It is indicated that the equations of the model groups can reflect in detail the relationship between the damage of storm surges and other related variables. Based on a comparison of the original value and the predicted value error, the model groups pass the test, providing scientific support and a decision basis for the early layout of disaster prevention and mitigation.

Evaluation of Loss Due to Storm Surge Disasters in China Based on Econometric Model Groups

Science.gov (United States)

Shi, Xiaoxia; Xu, Tongbin; Yin, Kedong

2018-01-01

Storm surge has become an important factor restricting the economic and social development of China’s coastal regions. In order to improve the scientific judgment of future storm surge damage, a method of model groups is proposed to refine the evaluation of the loss due to storm surges. Due to the relative dispersion and poor regularity of the natural property data (login center air pressure, maximum wind speed, maximum storm water, super warning water level, etc.), storm surge disaster is divided based on eight kinds of storm surge disaster grade division methods combined with storm surge water, hypervigilance tide level, and disaster loss. The storm surge disaster loss measurement model groups consist of eight equations, and six major modules are constructed: storm surge disaster in agricultural loss, fishery loss, human resource loss, engineering facility loss, living facility loss, and direct economic loss. Finally, the support vector machine (SVM) model is used to evaluate the loss and the intra-sample prediction. It is indicated that the equations of the model groups can reflect in detail the relationship between the damage of storm surges and other related variables. Based on a comparison of the original value and the predicted value error, the model groups pass the test, providing scientific support and a decision basis for the early layout of disaster prevention and mitigation. PMID:29584628

Evaluation of Loss Due to Storm Surge Disasters in China Based on Econometric Model Groups

Directory of Open Access Journals (Sweden)

Xue Jin

2018-03-01

Full Text Available Storm surge has become an important factor restricting the economic and social development of China’s coastal regions. In order to improve the scientific judgment of future storm surge damage, a method of model groups is proposed to refine the evaluation of the loss due to storm surges. Due to the relative dispersion and poor regularity of the natural property data (login center air pressure, maximum wind speed, maximum storm water, super warning water level, etc., storm surge disaster is divided based on eight kinds of storm surge disaster grade division methods combined with storm surge water, hypervigilance tide level, and disaster loss. The storm surge disaster loss measurement model groups consist of eight equations, and six major modules are constructed: storm surge disaster in agricultural loss, fishery loss, human resource loss, engineering facility loss, living facility loss, and direct economic loss. Finally, the support vector machine (SVM model is used to evaluate the loss and the intra-sample prediction. It is indicated that the equations of the model groups can reflect in detail the relationship between the damage of storm surges and other related variables. Based on a comparison of the original value and the predicted value error, the model groups pass the test, providing scientific support and a decision basis for the early layout of disaster prevention and mitigation.

Determining Storm Surge Return Periods: The Use of Evidence of Historic Events

DEFF Research Database (Denmark)

Madsen, Kristine S.; Sørensen, Carlo Sass; Schmith, Torben

Storm surges are a major concern for many coastal communities, and rising levels of surges is a key concern in relation to climate change. The sea level of a statistical 100-year or 1000-year storm surge event and similar statistical measures are used for spatial planning and emergency preparedness...

Adriatic storm surges and related cross-basin sea-level slope

Science.gov (United States)

Međugorac, Iva; Orlić, Mirko; Janeković, Ivica; Pasarić, Zoran; Pasarić, Miroslava

2018-05-01

Storm surges pose a severe threat to the northernmost cities of the Adriatic coast, with Venice being most prone to flooding. It has been noted that some flooding episodes cause significantly different effects along the eastern and western Adriatic coasts, with indications that the difference is related to cross-basin sea-level slope. The present study aims to determine specific atmospheric conditions under which the slope develops and to explore connection with increased sea level along the two coastlines. The analysis is based on sea-level time series recorded at Venice and Bakar over the 1984-2014 interval, from which 38 most intensive storm-surge episodes were selected, and their meteorological backgrounds (ERA-Interim) were studied. The obtained sea-level extremes were grouped into three categories according to their cross-basin sea-level slope: storm surges that slope strongly westward (W type), those that slope eastward (E type) and ordinary storm surges (O type). Results show that the slope is controlled by wind action only, specifically, by the wind component towards a particular coast and by the cross-basin shear of along-basin wind. Meteorological fields were used to force an oceanographic numerical model in order to confirm the empirically established connection between the atmospheric forcing and the slope. Finally, it has been found that the intensity of storm surges along a particular Adriatic coast is determined by an interplay of sea-level slopes in the along and cross-basin directions.

Multidecadal Scale Detection Time for Potentially Increasing Atlantic Storm Surges in a Warming Climate

Science.gov (United States)

Lee, Benjamin Seiyon; Haran, Murali; Keller, Klaus

2017-10-01

Storm surges are key drivers of coastal flooding, which generate considerable risks. Strategies to manage these risks can hinge on the ability to (i) project the return periods of extreme storm surges and (ii) detect potential changes in their statistical properties. There are several lines of evidence linking rising global average temperatures and increasingly frequent extreme storm surges. This conclusion is, however, subject to considerable structural uncertainty. This leads to two main questions: What are projections under various plausible statistical models? How long would it take to distinguish among these plausible statistical models? We address these questions by analyzing observed and simulated storm surge data. We find that (1) there is a positive correlation between global mean temperature rise and increasing frequencies of extreme storm surges; (2) there is considerable uncertainty underlying the strength of this relationship; and (3) if the frequency of storm surges is increasing, this increase can be detected within a multidecadal timescale (≈20 years from now).

Nonlinear chaotic model for predicting storm surges

Directory of Open Access Journals (Sweden)

M. Siek

2010-09-01

Full Text Available This paper addresses the use of the methods of nonlinear dynamics and chaos theory for building a predictive chaotic model from time series. The chaotic model predictions are made by the adaptive local models based on the dynamical neighbors found in the reconstructed phase space of the observables. We implemented the univariate and multivariate chaotic models with direct and multi-steps prediction techniques and optimized these models using an exhaustive search method. The built models were tested for predicting storm surge dynamics for different stormy conditions in the North Sea, and are compared to neural network models. The results show that the chaotic models can generally provide reliable and accurate short-term storm surge predictions.

Evaluation of Loss Due to Storm Surge Disasters in China Based on Econometric Model Groups

OpenAIRE

Xue Jin; Xiaoxia Shi; Jintian Gao; Tongbin Xu; Kedong Yin

2018-01-01

Storm surge has become an important factor restricting the economic and social development of China’s coastal regions. In order to improve the scientific judgment of future storm surge damage, a method of model groups is proposed to refine the evaluation of the loss due to storm surges. Due to the relative dispersion and poor regularity of the natural property data (login center air pressure, maximum wind speed, maximum storm water, super warning water level, etc.), storm surge disaster is di...

A Basis Function Approach to Simulate Storm Surge Events for Coastal Flood Risk Assessment

Science.gov (United States)

Wu, Wenyan; Westra, Seth; Leonard, Michael

2017-04-01

Storm surge is a significant contributor to flooding in coastal and estuarine regions, especially when it coincides with other flood producing mechanisms, such as extreme rainfall. Therefore, storm surge has always been a research focus in coastal flood risk assessment. Often numerical models have been developed to understand storm surge events for risk assessment (Kumagai et al. 2016; Li et al. 2016; Zhang et al. 2016) (Bastidas et al. 2016; Bilskie et al. 2016; Dalledonne and Mayerle 2016; Haigh et al. 2014; Kodaira et al. 2016; Lapetina and Sheng 2015), and assess how these events may change or evolve in the future (Izuru et al. 2015; Oey and Chou 2016). However, numeric models often require a lot of input information and difficulties arise when there are not sufficient data available (Madsen et al. 2015). Alternative, statistical methods have been used to forecast storm surge based on historical data (Hashemi et al. 2016; Kim et al. 2016) or to examine the long term trend in the change of storm surge events, especially under climate change (Balaguru et al. 2016; Oh et al. 2016; Rueda et al. 2016). In these studies, often the peak of surge events is used, which result in the loss of dynamic information within a tidal cycle or surge event (i.e. a time series of storm surge values). In this study, we propose an alternative basis function (BF) based approach to examine the different attributes (e.g. peak and durations) of storm surge events using historical data. Two simple two-parameter BFs were used: the exponential function and the triangular function. High quality hourly storm surge record from 15 tide gauges around Australia were examined. It was found that there are significantly location and seasonal variability in the peak and duration of storm surge events, which provides additional insights in coastal flood risk. In addition, the simple form of these BFs allows fast simulation of storm surge events and minimises the complexity of joint probability

Data Assimilation within the Advanced Circulation (ADCIRC) Modeling Framework for Hurricane Storm Surge Forecasting

KAUST Repository

Butler, T.

2012-07-01

Accurate, real-time forecasting of coastal inundation due to hurricanes and tropical storms is a challenging computational problem requiring high-fidelity forward models of currents and water levels driven by hurricane-force winds. Despite best efforts in computational modeling there will always be uncertainty in storm surge forecasts. In recent years, there has been significant instrumentation located along the coastal United States for the purpose of collecting data—specifically wind, water levels, and wave heights—during these extreme events. This type of data, if available in real time, could be used in a data assimilation framework to improve hurricane storm surge forecasts. In this paper a data assimilation methodology for storm surge forecasting based on the use of ensemble Kalman filters and the advanced circulation (ADCIRC) storm surge model is described. The singular evolutive interpolated Kalman (SEIK) filter has been shown to be effective at producing accurate results for ocean models using small ensemble sizes initialized by an empirical orthogonal function analysis. The SEIK filter is applied to the ADCIRC model to improve storm surge forecasting, particularly in capturing maximum water levels (high water marks) and the timing of the surge. Two test cases of data obtained from hindcast studies of Hurricanes Ike and Katrina are presented. It is shown that a modified SEIK filter with an inflation factor improves the accuracy of coarse-resolution forecasts of storm surge resulting from hurricanes. Furthermore, the SEIK filter requires only modest computational resources to obtain more accurate forecasts of storm surge in a constrained time window where forecasters must interact with emergency responders.

A Numerical Simulation of Extratropical Storm Surge and Hydrodynamic Response in the Bohai Sea

OpenAIRE

Ding, Yumei; Ding, Lei

2014-01-01

A hindcast of typical extratropical storm surge occurring in the Bohai Sea in October 2003 is performed using a three-dimensional (3D) Finite Volume Coastal Ocean Model (FVCOM). The storm surge model is forced by 10 m winds obtained from the Weather Research Forecasting (WRF) model simulation. It is shown that the simulated storm surge and tides agree well with the observations. The nonlinear interaction between the surge and astronomical tides, the spatial distribution of the max...

Storm surge evolution and its relationship to climate oscillations at Duck, NC

Science.gov (United States)

Munroe, Robert; Curtis, Scott

2017-07-01

Coastal communities experience increased vulnerability during storm surge events through the risk of damage to coastal infrastructure, erosion/deposition, and the endangerment of human life. Policy and planning measures attempt to avoid or mitigate storm surge consequences through building codes and setbacks, beach stabilization, insurance rates, and coastal zoning. The coastal emergency management community and public react and respond on shorter time scales, through temporary protection, emergency stockpiling, and evacuation. This study utilizes time series analysis, the Kolmogorov-Smirnov (K-S) test, Pearson's correlation, and the generalized extreme value (GEV) theorem to make the connection between climate oscillation indices and storm surge characteristics intra-seasonally to inter-annually. Results indicate that an El Niño (+ENSO), negative phase of the NAO, and positive phase of the PNA pattern all support longer duration and hence more powerful surge events, especially in winter. Increased surge duration increases the likelihood of extensive erosion, inland inundation, among other undesirable effects of the surge hazard.

Impacts of Storm Surge Mitigation Strategies on Aboveground Storage Tank Chemical Spill Transport

Science.gov (United States)

Do, C.; Bass, B. J.; Bernier, C.; Samii, A.; Dawson, C.; Bedient, P. B.

2017-12-01

The Houston Ship Channel (HSC), located in the hurricane-prone Houston-Galveston region of the upper Texas Coast, is one of the busiest waterways in the United States and is home to one of the largest petrochemical complexes in the world. Due to the proximity of the HSC to Galveston Bay and the Gulf of Mexico, chemical spills resulting from storm surge damage to aboveground storage tanks (ASTs) pose serious threats to the environment, residential communities, and national/international markets whose activities in the HSC generate billions of dollars annually. In an effort to develop a comprehensive storm surge mitigation strategy for Galveston Bay and its constituents, Rice University's Severe Storm Prediction, Education, and Evacuation from Disasters Center proposed two structural storm surge mitigation concepts, the Mid Bay Structure (MBS) and the Lower Bay Structure (LBS) as components of the Houston-Galveston Area Protection System (H-GAPS) project. The MBS consists of levees along the HSC and a navigational gate across the channel, and the LBS consists of a navigation gate and environmental gates across Bolivar Road. The impacts of these two barrier systems on the fate of AST chemical spills in the HSC have previously been unknown. This study applies the coupled 2D SWAN+ADCIRC model to simulate hurricane storm surge circulation within the Gulf of Mexico and Galveston Bay due to a synthetic storm which results in approximately 250-year surge levels in Galveston Bay. The SWAN+ADCIRC model is run using high-resolution computational meshes that incorporate the MBS and LBS scenarios, separately. The resulting wind and water velocities are then fed into a Lagrangian particle transport model to simulate the spill trajectories of the ASTs most likely to fail during the 250-year proxy storm. Results from this study illustrate how each storm surge mitigation strategy impacts the transport of chemical spills (modeled as Lagrangian particles) during storm surge as

Modeling Flood Inundation Induced by River Flow and Storm Surges over a River Basin

Directory of Open Access Journals (Sweden)

Wei-Bo Chen

2014-10-01

Full Text Available Low-lying coastal regions and their populations are at risk during storm surge events and high freshwater discharges from upriver. An integrated storm surge and flood inundation modeling system was used to simulate storm surge and inundation in the Tsengwen River basin and the adjacent coastal area in southern Taiwan. A three-dimensional hydrodynamic model with an unstructured grid was used, which was driven by the tidal elevation at the open boundaries and freshwater discharge at the upriver boundary. The model was validated against the observed water levels for three typhoon events. The simulation results for the model were in reasonable agreement with the observational data. The model was then applied to investigate the effects of a storm surge, freshwater discharge, and a storm surge combined with freshwater discharge during an extreme typhoon event. The super Typhoon Haiyan (2013 was artificially shifted to hit Taiwan: the modeling results showed that the inundation area and depth would cause severe overbank flow and coastal flooding for a 200 year return period flow. A high-resolution grid model is essential for the accurate simulation of storm surges and inundation.

Modeling and simulation of storm surge on Staten Island to understand inundation mitigation strategies

Science.gov (United States)

Kress, Michael E.; Benimoff, Alan I.; Fritz, William J.; Thatcher, Cindy A.; Blanton, Brian O.; Dzedzits, Eugene

2016-01-01

Hurricane Sandy made landfall on October 29, 2012, near Brigantine, New Jersey, and had a transformative impact on Staten Island and the New York Metropolitan area. Of the 43 New York City fatalities, 23 occurred on Staten Island. The borough, with a population of approximately 500,000, experienced some of the most devastating impacts of the storm. Since Hurricane Sandy, protective dunes have been constructed on the southeast shore of Staten Island. ADCIRC+SWAN model simulations run on The City University of New York's Cray XE6M, housed at the College of Staten Island, using updated topographic data show that the coast of Staten Island is still susceptible to tidal surge similar to those generated by Hurricane Sandy. Sandy hindcast simulations of storm surges focusing on Staten Island are in good agreement with observed storm tide measurements. Model results calculated from fine-scaled and coarse-scaled computational grids demonstrate that finer grids better resolve small differences in the topography of critical hydraulic control structures, which affect storm surge inundation levels. The storm surge simulations, based on post-storm topography obtained from high-resolution lidar, provide much-needed information to understand Staten Island's changing vulnerability to storm surge inundation. The results of fine-scale storm surge simulations can be used to inform efforts to improve resiliency to future storms. For example, protective barriers contain planned gaps in the dunes to provide for beach access that may inadvertently increase the vulnerability of the area.

Use of historical information in extreme storm surges frequency analysis

Science.gov (United States)

Hamdi, Yasser; Duluc, Claire-Marie; Deville, Yves; Bardet, Lise; Rebour, Vincent

2013-04-01

The prevention of storm surge flood risks is critical for protection and design of coastal facilities to very low probabilities of failure. The effective protection requires the use of a statistical analysis approach having a solid theoretical motivation. Relating extreme storm surges to their frequency of occurrence using probability distributions has been a common issue since 1950s. The engineer needs to determine the storm surge of a given return period, i.e., the storm surge quantile or design storm surge. Traditional methods for determining such a quantile have been generally based on data from the systematic record alone. However, the statistical extrapolation, to estimate storm surges corresponding to high return periods, is seriously contaminated by sampling and model uncertainty if data are available for a relatively limited period. This has motivated the development of approaches to enlarge the sample extreme values beyond the systematic period. The nonsystematic data occurred before the systematic period is called historical information. During the last three decades, the value of using historical information as a nonsystematic data in frequency analysis has been recognized by several authors. The basic hypothesis in statistical modeling of historical information is that a perception threshold exists and that during a giving historical period preceding the period of tide gauging, all exceedances of this threshold have been recorded. Historical information prior to the systematic records may arise from high-sea water marks left by extreme surges on the coastal areas. It can also be retrieved from archives, old books, earliest newspapers, damage reports, unpublished written records and interviews with local residents. A plotting position formula, to compute empirical probabilities based on systematic and historical data, is used in this communication paper. The objective of the present work is to examine the potential gain in estimation accuracy with the

Idealised modelling of storm surges in large-scale coastal basins

NARCIS (Netherlands)

Chen, Wenlong

2015-01-01

Coastal areas around the world are frequently attacked by various types of storms, threatening human life and property. This study aims to understand storm surge processes in large-scale coastal basins, particularly focusing on the influences of geometry, topography and storm characteristics on the

Simulating Storm Surge Impacts with a Coupled Atmosphere-Inundation Model with Varying Meteorological Forcing

Directory of Open Access Journals (Sweden)

Alexandra N. Ramos Valle

2018-04-01

Full Text Available Storm surge events have the potential to cause devastating damage to coastal communities. The magnitude of their impacts highlights the need for increased accuracy and real-time forecasting and predictability of storm surge. In this study, we assess two meteorological forcing configurations to hindcast the storm surge of Hurricane Sandy, and ultimately support the improvement of storm surge forecasts. The Weather Research and Forecasting (WRF model is coupled to the ADvanced CIRCulation Model (ADCIRC to determine water elevations. We perform four coupled simulations and compare storm surge estimates resulting from the use of a parametric vortex model and a full-physics atmospheric model. One simulation is forced with track-based meteorological data calculated from WRF, while three simulations are forced with the full wind and pressure field outputs from WRF simulations of varying resolutions. Experiments were compared to an ADCIRC simulation forced by National Hurricane Center best track data, as well as to station observations. Our results indicated that given accurate meteorological best track data, a parametric vortex model can accurately forecast maximum water elevations, improving upon the use of a full-physics coupled atmospheric-surge model. In the absence of a best track, atmospheric forcing in the form of full wind and pressure field from a high-resolution atmospheric model simulation prove reliable for storm surge forecasting.

The Use of a Statistical Model of Storm Surge as a Bias Correction for Dynamical Surge Models and its Applicability along the U.S. East Coast

Directory of Open Access Journals (Sweden)

Haydee Salmun

2015-02-01

Full Text Available The present study extends the applicability of a statistical model for prediction of storm surge originally developed for The Battery, NY in two ways: I. the statistical model is used as a biascorrection for operationally produced dynamical surge forecasts, and II. the statistical model is applied to the region of the east coast of the U.S. susceptible to winter extratropical storms. The statistical prediction is based on a regression relation between the “storm maximum” storm surge and the storm composite significant wave height predicted ata nearby location. The use of the statistical surge prediction as an alternative bias correction for the National Oceanic and Atmospheric Administration (NOAA operational storm surge forecasts is shownhere to be statistically equivalent to the existing bias correctiontechnique and potentially applicable for much longer forecast lead times as well as for storm surge climate prediction. Applying the statistical model to locations along the east coast shows that the regression relation can be “trained” with data from tide gauge measurements and near-shore buoys along the coast from North Carolina to Maine, and that it provides accurate estimates of storm surge.

Tropical cyclone induced asymmetry of sea level surge and fall and its presentation in a storm surge model with parametric wind fields

Science.gov (United States)

Peng, Machuan; Xie, Lian; Pietrafesa, Leonard J.

The asymmetry of tropical cyclone induced maximum coastal sea level rise (positive surge) and fall (negative surge) is studied using a three-dimensional storm surge model. It is found that the negative surge induced by offshore winds is more sensitive to wind speed and direction changes than the positive surge by onshore winds. As a result, negative surge is inherently more difficult to forecast than positive surge since there is uncertainty in tropical storm wind forecasts. The asymmetry of negative and positive surge under parametric wind forcing is more apparent in shallow water regions. For tropical cyclones with fixed central pressure, the surge asymmetry increases with decreasing storm translation speed. For those with the same translation speed, a weaker tropical cyclone is expected to gain a higher AI (asymmetry index) value though its induced maximum surge and fall are smaller. With fixed RMW (radius of maximum wind), the relationship between central pressure and AI is heterogeneous and depends on the value of RMW. Tropical cyclone's wind inflow angle can also affect surge asymmetry. A set of idealized cases as well as two historic tropical cyclones are used to illustrate the surge asymmetry.

Development of Storm Surge Hazard Maps and Advisory System for the Philippines

Science.gov (United States)

Santiago, Joy; Mahar Francisco Lagymay, Alfredo; Caro, Carl Vincent; Suarez, John Kenneth; Tablazon, Judd; Dasallas, Lea; Garnet Goting, Prince

2016-04-01

The Philippines, located in the most active region of cyclogenesis in the world, experiences an average of 20 tropical cyclones annually. Strong winds brought by tropical cyclones, among other factors, cause storm surges that inundate the coastal areas of the country. As an archipelago with the fourth longest coastline in the world, the country is expose to the threats of storm surges. This was manifested by Typhoon Haiyan on 8 November 2013, which devastated the country and left 6,293 deaths and approximately USD 2 billion worth of damages. To prevent such disaster from happening again, the Nationwide Operational Assessment of Hazards (Project NOAH) developed a Storm Surge Advisory (SSA) that aims to warn communities in coastal areas against impending floods due to storm surges. The Japan Meteorological Agency storm surge model was used to simulate 721 tropical cyclones that entered the Philippine Area of Responsibility from 1951-2013. The resulting storm surge time series from the simulations were added to the maximum tide levels from the WXTide software for the 4,996 observation points placed nearshore in the entire country. The storm tide levels were categorized into four groups based on their peak height to create the SSA - SSA 1 (0.01m to 2m), SSA 2 (2.01m to 3m), SSA 3 (3.01m to 4m), and SSA 4 (4m and above). The time series for each advisory level was used in inundation modelling using FLO-2D, a two-dimensional flood modeling software that uses continuity and dynamic wave momentum equation. The model produced probable extent, depth of inundation, and hazard level for each advisory level. The SSA hazard maps are used as reference to warn communities that are likely to be affected by storm surges. Advisory is released 24 hours in advance and is updated every six hours in the Project NOAH website. It is also being utilized in the pre-disaster risk assessment of the national government agencies and local government units in designing appropriate response to

Storm-surge flooding on the Yukon-Kuskokwim Delta, Alaska

Science.gov (United States)

Terenzi, John; Ely, Craig R.; Jorgenson, M. Torre

2014-01-01

Coastal regions of Alaska are regularly affected by intense storms of ocean origin, the frequency and intensity of which are expected to increase as a result of global climate change. The Yukon-Kuskokwim Delta (YKD), situated in western Alaska on the eastern edge of the Bering Sea, is one of the largest deltaic systems in North America. Its low relief makes it especially susceptible to storm-driven flood tides and increases in sea level. Little information exists on the extent of flooding caused by storm surges in western Alaska and its effects on salinization, shoreline erosion, permafrost thaw, vegetation, wildlife, and the subsistence-based economy. In this paper, we summarize storm flooding events in the Bering Sea region of western Alaska during 1913 – 2011 and map both the extent of inland flooding caused by autumn storms on the central YKD, using Radarsat-1 and MODIS satellite imagery, and the drift lines, using high-resolution IKONOS satellite imagery and field surveys. The largest storm surges occurred in autumn and were associated with high tides and strong (> 65 km hr-1) southwest winds. Maximum inland extent of flooding from storm surges was 30.3 km in 2005, 27.4 km in 2006, and 32.3 km in 2011, with total flood area covering 47.1%, 32.5%, and 39.4% of the 6730 km2 study area, respectively. Peak stages for the 2005 and 2011 storms were 3.1 m and 3.3 m above mean sea level, respectively—almost as high as the 3.5 m amsl elevation estimated for the largest storm observed (in November 1974). Several historically abandoned village sites lie within the area of inundation of the largest flood events. With projected sea level rise, large storms are expected to become more frequent and cover larger areas, with deleterious effects on freshwater ponds, non-saline habitats, permafrost, and landscapes used by nesting birds and local people.

Probabilistic hurricane-induced storm surge hazard assessment in Guadeloupe, Lesser Antilles

Science.gov (United States)

Krien, Y.; Dudon, B.; Roger, J.; Zahibo, N.

2015-08-01

Current storm surge hazard maps in the French West Indies are essentially based on simple statistical methods using limited historical data and early low-resolution models which do not take the effect of waves into account. In this paper, we infer new 100-year and 1000-year surge levels in Guadeloupe from the numerical modelling of storm surges induced by a large set of synthetic events that are in statistical agreement with features of historical hurricanes in the North Atlantic Basin between 1980 and 2011. Computations are performed using the wave-current coupled model ADCIRC-SWAN with high grid resolutions (up to 40-60 m) in the coastal and wave dissipation areas. This model is validated against observations during past events such as hurricane HUGO (1989). Results are generally found to be in reasonable agreement with past studies in areas where surge is essentially wind-driven, but found to differ significantly in coastal regions where the transfer of momentum from waves to the water column constitutes a non-negligible part of the total surge. The methodology, which can be applied to other islands in the Lesser Antilles, allows storm surge level maps to be obtained that can be of major interest for coastal planners and decision makers in terms of risk management.

The Effect of Coastal Development on Storm Surge Flooding in Biscayne Bay, Florida, USA (Invited)

Science.gov (United States)

Zhang, K.; Liu, H.; Li, Y.

2013-12-01

Barrier islands and associated bays along the Atlantic and Gulf Coasts are a favorite place for both living and visiting. Many of them are vulnerable to storm surge flooding because of low elevations and constantly being subjected to the impacts of storms. The population increase and urban development along the barrier coast have altered the shoreline configuration, resulting in a dramatic change in the coastal flooding pattern in some areas. Here we present such a case based on numerical simulations of storm surge flooding caused by the1926 hurricane in the densely populated area surrounding Biscayne Bay in Miami, Florida. The construction of harbor and navigation channels, and the development of real estate and the roads connecting islands along Biscayne Bay have changed the geometry of Biscayne Bay since 1910s. Storm surge simulations show that the Port of Miami and Dodge Island constructed by human after 1950 play an important role in changing storm surge inundation pattern along Biscayne Bay. Dodge Island enhances storm surge and increases inundation in the area south of the island, especially at the mouth of Miami River (Downtown of Miami), and reduces storm surge flooding in the area north of the island, especially in Miami Beach. If the Hurricane Miami of 1926 happened today, the flooding area would be reduced by 55% and 20% in the Miami Beach and North Miami areas, respectively. Consequently, it would prevent 400 million of property and 10 thousand people from surge flooding according to 2010 U.S census and 2007 property tax data. Meanwhile, storm water would penetrate further inland south of Dodge Island and increase the flooding area by 25% in the Miami River and Downtown Miami areas. As a result, 200 million of property and five thousand people would be impacted by storm surge.

The analysis of dependence between extreme rainfall and storm surge in the coastal zone

Science.gov (United States)

Zheng, F.; Westra, S.

2012-12-01

Flooding in coastal catchments can be caused by runoff generated by an extreme rainfall event, elevated sea levels due to an extreme storm surge event, or the combination of both processes occurring simultaneously or in close succession. Dependence in extreme rainfall and storm surge arises because common meteorological forcings often drive both variables; for example, cyclonic systems may produce extreme rainfall, strong onshore winds and an inverse barometric effect simultaneously, which the former factor influencing catchment discharge and the latter two factors influencing storm surge. Nevertheless there is also the possibility that only one of the variables is extreme at any given time, so that the dependence between rainfall and storm surge is not perfect. Quantification of the strength of dependence between these processes is critical in evaluating the magnitude of flood risk in the coastal zone. This may become more important in the future as the majority of the coastal areas are threatened by the sea level rise due to the climate change. This research uses the most comprehensive record of rainfall and storm surge along the coastline of Australia collected to-date to investigate the strength of dependence between the extreme rainfall and storm surge along the Australia coastline. A bivariate logistic threshold-excess model was employed to this end to carry out the dependence analysis. The strength of the estimated dependence is then evaluated as a function of several factors including: the distance between the tidal gauge and the rain gauge; the lag between the extreme precipitation event and extreme surge event; and the duration of the maximum storm burst. The results show that the dependence between the extreme rainfall and storm surge along the Australia coastline is statistically significant, although some locations clearly exhibit stronger dependence than others. We hypothesize that this is due to a combination of large-scale meteorological effects as

Rapid wave and storm surge warning system for tropical cyclones in Mexico

Science.gov (United States)

Appendini, C. M.; Rosengaus, M.; Meza, R.; Camacho, V.

2015-12-01

The National Hurricane Center (NHC) in Miami, is responsible for the forecast of tropical cyclones in the North Atlantic and Eastern North Pacific basins. As such, Mexico, Central America and Caribbean countries depend on the information issued by the NHC related to the characteristics of a particular tropical cyclone and associated watch and warning areas. Despite waves and storm surge are important hazards for marine operations and coastal dwellings, their forecast is not part of the NHC responsibilities. This work presents a rapid wave and storm surge warning system based on 3100 synthetic tropical cyclones doing landfall in Mexico. Hydrodynamic and wave models were driven by the synthetic events to create a robust database composed of maximum envelops of wind speed, significant wave height and storm surge for each event. The results were incorporated into a forecast system that uses the NHC advisory to locate the synthetic events passing inside specified radiuses for the present and forecast position of the real event. Using limited computer resources, the system displays the information meeting the search criteria, and the forecaster can select specific events to generate the desired hazard map (i.e. wind, waves, and storm surge) based on the maximum envelop maps. This system was developed in a limited time frame to be operational in 2015 by the National Hurricane and Severe Storms Unit of the Mexican National Weather Service, and represents a pilot project for other countries in the region not covered by detailed storm surge and waves forecasts.

Numerical Evaluation of Storm Surge Indices for Public Advisory Purposes

Science.gov (United States)

Bass, B.; Bedient, P. B.; Dawson, C.; Proft, J.

2016-12-01

After the devastating hurricane season of 2005, shortcomings with the Saffir-Simpson Hurricane Scale's (SSHS) ability to characterize a tropical cyclones potential to generate storm surge became widely apparent. As a result, several alternative surge indices were proposed to replace the SSHS, including Powell and Reinhold's Integrated Kinetic Energy (IKE) factor, Kantha's Hurricane Surge Index (HSI), and Irish and Resio's Surge Scale (SS). Of the previous, the IKE factor is the only surge index to-date that truly captures a tropical cyclones integrated intensity, size, and wind field distribution. However, since the IKE factor was proposed in 2007, an accurate assessment of this surge index has not been performed. This study provides the first quantitative evaluation of the IKEs ability to serve as a predictor of a tropical cyclones potential surge impacts as compared to other alternative surge indices. Using the tightly coupled ADvanced CIRCulation and Simulating WAves Nearshore models, the surge and wave responses of Hurricane Ike (2008) and 78 synthetic tropical cyclones were evaluated against the SSHS, IKE, HSI and SS. Results along the upper TX coast of the Gulf of Mexico demonstrate that the HSI performs best in capturing the peak surge response of a tropical cyclone, while the IKE accounting for winds greater than tropical storm intensity (IKETS) provides the most accurate estimate of a tropical cyclones regional surge impacts. These results demonstrate that the appropriate selection of a surge index ultimately depends on what information is of interest to be conveyed to the public and/or scientific community.

The Development of Storm Surge Ensemble Prediction System and Case Study of Typhoon Meranti in 2016

Science.gov (United States)

Tsai, Y. L.; Wu, T. R.; Terng, C. T.; Chu, C. H.

2017-12-01

Taiwan is under the threat of storm surge and associated inundation, which is located at a potentially severe storm generation zone. The use of ensemble prediction can help forecasters to know the characteristic of storm surge under the uncertainty of track and intensity. In addition, it can help the deterministic forecasting. In this study, the kernel of ensemble prediction system is based on COMCOT-SURGE (COrnell Multi-grid COupled Tsunami Model - Storm Surge). COMCOT-SURGE solves nonlinear shallow water equations in Open Ocean and coastal regions with the nested-grid scheme and adopts wet-dry-cell treatment to calculate potential inundation area. In order to consider tide-surge interaction, the global TPXO 7.1 tide model provides the tidal boundary conditions. After a series of validations and case studies, COMCOT-SURGE has become an official operating system of Central Weather Bureau (CWB) in Taiwan. In this study, the strongest typhoon in 2016, Typhoon Meranti, is chosen as a case study. We adopt twenty ensemble members from CWB WRF Ensemble Prediction System (CWB WEPS), which differs from parameters of microphysics, boundary layer, cumulus, and surface. From box-and-whisker results, maximum observed storm surges were located in the interval of the first and third quartile at more than 70 % gauge locations, e.g. Toucheng, Chengkung, and Jiangjyun. In conclusion, the ensemble prediction can effectively help forecasters to predict storm surge especially under the uncertainty of storm track and intensity

Effects of cluster land reclamation projects on storm surge in Jiaojiang Estuary, China

Directory of Open Access Journals (Sweden)

Zhi-lin Sun

2017-01-01

Full Text Available Variations in coastline geometry caused by coastal engineering affect tides, storm surges, and storm tides. Three cluster land reclamation projects have been planned for construction in the Jiaojiang Estuary during the period from 2011 to 2023. They will cause significant changes in coastline geometry. In this study, a surge-tide coupled model was established based on a three-dimensional finite-volume coastal ocean model (FVCOM. A series of numerical experiments were carried out to investigate the effects of variations in coastline geometry on tides, storm surges, and storm tides. This model was calibrated using data observed at the Haimen and Ruian gauge stations and then used to reproduce the tides, storm surges, and storm tides in the Jiaojiang Estuary caused by Typhoon Winnie in 1997. Results show that the high tide level, peak storm surge, and high storm tide level at the Haimen Gauge Station increased along with the completion of reclamation projects, and the maximum increments caused by the third project were 0.13 m, 0.50 m, and 0.43 m, respectively. The envelopes with maximum storm tide levels of 7.0 m and 8.0 m inside the river mouth appeared to move seaward, with the latter shifting 1.8 km, 3.3 km, and 4.4 km due to the first project, second project, and third project, respectively. The results achieved in this study contribute to reducing the effects of, and preventing storm disasters after the land reclamation in the Jiaojiang Estuary.

High Resolution Hurricane Storm Surge and Inundation Modeling (Invited)

Science.gov (United States)

Luettich, R.; Westerink, J. J.

2010-12-01

Coastal counties are home to nearly 60% of the U.S. population and industry that accounts for over 16 million jobs and 10% of the U.S. annual gross domestic product. However, these areas are susceptible to some of the most destructive forces in nature, including tsunamis, floods, and severe storm-related hazards. Since 1900, tropical cyclones making landfall on the US Gulf of Mexico Coast have caused more than 9,000 deaths; nearly 2,000 deaths have occurred during the past half century. Tropical cyclone-related adjusted, annualized losses in the US have risen from 1.3 billion from 1949-1989, to 10.1 billion from 1990-1995, and $35.8 billion per year for the period 2001-2005. The risk associated with living and doing business in the coastal areas that are most susceptible to tropical cyclones is exacerbated by rising sea level and changes in the characteristics of severe storms associated with global climate change. In the five years since hurricane Katrina devastated the northern Gulf of Mexico Coast, considerable progress has been made in the development and utilization of high resolution coupled storm surge and wave models. Recent progress will be presented with the ADCIRC + SWAN storm surge and wave models. These tightly coupled models use a common unstructured grid in the horizontal that is capable of covering large areas while also providing high resolution (i.e., base resolution down to 20m plus smaller subgrid scale features such as sea walls and levees) in areas that are subject to surge and inundation. Hydrodynamic friction and overland winds are adjusted to account for local land cover. The models scale extremely well on modern high performance computers allowing rapid turnaround on large numbers of compute cores. The models have been adopted for FEMA National Flood Insurance Program studies, hurricane protection system design and risk analysis, and quasi-operational forecast systems for several regions of the country. They are also being evaluated as

Data Assimilation within the Advanced Circulation (ADCIRC) Modeling Framework for Hurricane Storm Surge Forecasting

KAUST Repository

Butler, T.; Altaf, Muhammad; Dawson, C.; Hoteit, Ibrahim; Luo, X.; Mayo, T.

2012-01-01

levels, and wave heights—during these extreme events. This type of data, if available in real time, could be used in a data assimilation framework to improve hurricane storm surge forecasts. In this paper a data assimilation methodology for storm surge

Using satellite altimetry and tide gauges for storm surge warning

DEFF Research Database (Denmark)

Andersen, O. B.; Cheng, Yongcun; Deng, X.

2014-01-01

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...

On the improvement of wave and storm surge hindcasts by downscaled atmospheric forcing: application to historical storms

Science.gov (United States)

Bresson, Émilie; Arbogast, Philippe; Aouf, Lotfi; Paradis, Denis; Kortcheva, Anna; Bogatchev, Andrey; Galabov, Vasko; Dimitrova, Marieta; Morvan, Guillaume; Ohl, Patrick; Tsenova, Boryana; Rabier, Florence

2018-04-01

Winds, waves and storm surges can inflict severe damage in coastal areas. In order to improve preparedness for such events, a better understanding of storm-induced coastal flooding episodes is necessary. To this end, this paper highlights the use of atmospheric downscaling techniques in order to improve wave and storm surge hindcasts. The downscaling techniques used here are based on existing European Centre for Medium-Range Weather Forecasts reanalyses (ERA-20C, ERA-40 and ERA-Interim). The results show that the 10 km resolution data forcing provided by a downscaled atmospheric model gives a better wave and surge hindcast compared to using data directly from the reanalysis. Furthermore, the analysis of the most extreme mid-latitude cyclones indicates that a four-dimensional blending approach improves the whole process, as it assimilates more small-scale processes in the initial conditions. Our approach has been successfully applied to ERA-20C (the 20th century reanalysis).

Estimating Areas of Vulnerability: Sea Level Rise and Storm Surge Hazards in the National Parks

Science.gov (United States)

Caffrey, M.; Beavers, R. L.; Slayton, I. A.

2013-12-01

The University of Colorado Boulder in collaboration with the National Park Service has undertaken the task of compiling sea level change and storm surge data for 105 coastal parks. The aim of our research is to highlight areas of the park system that are at increased risk of rapid inundation as well as periodic flooding due to sea level rise and storms. This research will assist park managers and planners in adapting to climate change. The National Park Service incorporates climate change data into many of their planning documents and is willing to implement innovative coastal adaptation strategies. Events such as Hurricane Sandy highlight how impacts of coastal hazards will continue to challenge management of natural and cultural resources and infrastructure along our coastlines. This poster will discuss the current status of this project. We discuss the impacts of Hurricane Sandy as well as the latest sea level rise and storm surge modeling being employed in this project. In addition to evaluating various drivers of relative sea-level change, we discuss how park planners and managers also need to consider projected storm surge values added to sea-level rise magnitudes, which could further complicate the management of coastal lands. Storm surges occurring at coastal parks will continue to change the land and seascapes of these areas, with the potential to completely submerge them. The likelihood of increased storm intensity added to increasing rates of sea-level rise make predicting the reach of future storm surges essential for planning and adaptation purposes. The National Park Service plays a leading role in developing innovative strategies for coastal parks to adapt to sea-level rise and storm surge, whilst coastal storms are opportunities to apply highly focused responses.

Typhoon Haiyan-Induced Storm Surge Simulation in Metro Manila Using High-Resolution LiDAR Topographic Data

Science.gov (United States)

Santiago, J. T.

2015-12-01

Storm surge is the abnormal rise in sea water over and above astronomical tides due to a forthcoming storm. Developing an early warning system for storm surges is vital due to the high level of hazard they might cause. On 08 November 2013, Typhoon Haiyan generated storm surges that killed over 6,000 people in the central part of the Philippines. The Nationwide Operational Assessment of Hazards under the Department of Science and Technology was tasked to create storm surge hazard maps for the country's coastal areas. The research project aims to generate storm surge hazard maps that can be used for disaster mitigation and planning. As part of the research, the team explored a scenario wherein a tropical cyclone hits the Metro Manila with strength as strong as Typhoon Haiyan. The area was chosen primarily for its political, economic and cultural significance as the country's capital. Using Japan Meteorological Agency Storm Surge model, FLO2D flooding software, LiDAR topographic data, and GIS technology, the effects of a Haiyan-induced tropical cyclone passing through Metro Manila was examined. The population affected, number of affected critical facilities, and potential evacuation sites were identified. The outputs of this study can be used by the authorities as basis for policies that involve disaster risk reduction and management.

An Exploration of Wind Stress Calculation Techniques in Hurricane Storm Surge Modeling

Directory of Open Access Journals (Sweden)

Kyra M. Bryant

2016-09-01

Full Text Available As hurricanes continue to threaten coastal communities, accurate storm surge forecasting remains a global priority. Achieving a reliable storm surge prediction necessitates accurate hurricane intensity and wind field information. The wind field must be converted to wind stress, which represents the air-sea momentum flux component required in storm surge and other oceanic models. This conversion requires a multiplicative drag coefficient for the air density and wind speed to represent the air-sea momentum exchange at a given location. Air density is a known parameter and wind speed is a forecasted variable, whereas the drag coefficient is calculated using an empirical correlation. The correlation’s accuracy has brewed a controversy of its own for more than half a century. This review paper examines the lineage of drag coefficient correlations and their acceptance among scientists.

Simulating storm surge inundation and damage potential within complex port facilities

Science.gov (United States)

Mawdsley, Robert; French, Jon; Fujiyama, Taku; Achutan, Kamalasudhan

2017-04-01

Storm surge inundation of port facilities can cause damage to critical elements of infrastructure, significantly disrupt port operations and cause downstream impacts on vital supply chains. A tidal surge in December 2013 in the North Sea partly flooded the Port of Immingham, which handles the largest volume of bulk cargo in the UK including major flows of coal and biomass for power generation. This flooding caused damage to port and rail transport infrastructure and disrupted operations for several weeks. This research aims to improve resilience to storm surges using hydrodynamic modelling coupled to an agent-based model of port operations. Using the December 2013 event to validate flood extent, depth and duration, we ran a high resolution hydrodynamic simulation using the open source Telemac 2D finite element code. The underlying Digital Elevation Model (DEM) was derived from Environment Agency LiDAR data, with ground truthing of the flood defences along the port frontage. Major infrastructure and buildings are explicitly resolved with varying degrees of permeability. Telemac2D simulations are run in parallel and take only minutes on a single 16 cpu compute node. Inundation characteristics predicted using Telemac 2D differ from a simple Geographical Information System 'bath-tub' analysis of the DEM based upon horizontal application of the maximum water level across the port topography. The hydrodynamic simulation predicts less extensive flooding and more closely matches observed flood extent. It also provides more precise depth and duration curves. Detailed spatial flood depth and duration maps were generated for a range of tide and surge scenarios coupled to mean sea-level rise projections. These inundation scenarios can then be integrated with critical asset databases and an agent-based model of port operation (MARS) that is capable of simulating storm surge disruption along wider supply chains. Port operators are able to act on information from a particular

Storm Surge Modeling of Typhoon Haiyan at the Naval Oceanographic Office Using Delft3D

Science.gov (United States)

Gilligan, M. J.; Lovering, J. L.

2016-02-01

The Naval Oceanographic Office provides estimates of the rise in sea level along the coast due to storm surge associated with tropical cyclones, typhoons, and hurricanes. Storm surge modeling and prediction helps the US Navy by providing a threat assessment tool to help protect Navy assets and provide support for humanitarian assistance/disaster relief efforts. Recent advancements in our modeling capabilities include the use of the Delft3D modeling suite as part of a Naval Research Laboratory (NRL) developed Coastal Surge Inundation Prediction System (CSIPS). Model simulations were performed on Typhoon Haiyan, which made landfall in the Philippines in November 2013. Comparisons of model simulations using forecast and hindcast track data highlight the importance of accurate storm track information for storm surge predictions. Model runs using the forecast track prediction and hindcast track information give maximum storm surge elevations of 4 meters and 6.1 meters, respectively. Model results for the hindcast simulation were compared with data published by the JSCE-PICE Joint survey for locations in San Pedro Bay (SPB) and on the Eastern Samar Peninsula (ESP). In SPB, where wind-induced set-up predominates, the model run using the forecast track predicted surge within 2 meters in 38% of survey locations and within 3 meters in 59% of the locations. When the hindcast track was used, the model predicted within 2 meters in 77% of the locations and within 3 meters in 95% of the locations. The model was unable to predict the high surge reported along the ESP produced by infragravity wave-induced set-up, which is not simulated in the model. Additional modeling capabilities incorporating infragravity waves are required to predict storm surge accurately along open coasts with steep bathymetric slopes, such as those seen in island arcs.

Risks of Coastal Storm Surge and the Effect of Sea Level Rise in the Red River Delta, Vietnam

OpenAIRE

Neumann, James; Ludwig, Lindsay; Verly, Caroleen; Emanuel, Kerry Andrew; Ravela, Srinivas

2015-01-01

This paper considers the impact of sea level rise and storm surge on the Red River delta region of Vietnam an area already known to be highly vulnerable to coastal risks. By combining a range of sea level rise scenarios for 2050 with the simulated storm surge level for the 100-year storm surge, we analyze permanently inundated lands and temporary flood zones. As is well-established in the literature, sea level rise will increase the risk of storms by raising the base sea level from which surg...

Risks of Coastal Storm Surge and the Effect of Sea Level Rise in the Red River Delta, Vietnam

Directory of Open Access Journals (Sweden)

James E. Neumann

2015-05-01

Full Text Available This paper considers the impact of sea level rise and storm surge on the Red River delta region of Vietnam. Permanently inundated lands and temporary flood zones are analyzed by combining sea level rise scenarios for 2050 with simulated storm surge levels for the 100-year event. Our analysis finds that sea level rise through 2050 could increase the effective frequency of the current 100-year storm surge, which is associated with a storm surge of roughly five meters, to once every 49 years. Approximately 10% of the Hanoi region’s GDP is vulnerable to permanent inundation due to sea level rise, and more than 40% is vulnerable to periodic storm surge damage consistent with the current 100-year storm. We conclude that coastal adaptation measures, such as a planned retreat from the sea, and construction of a more substantial seawall and dike system, are needed to respond to these threats.

Assessment of the Temporal Evolution of Storm Surge via Land to Water Isopleths in Coastal Louisiana

Science.gov (United States)

Siverd, C. G.; Hagen, S. C.; Bilskie, M. V.; Braud, D.; Gao, S.; Peele, H.; Twilley, R.

2017-12-01

The low-lying coastal Louisiana deltaic landscape features an intricate system of fragmented wetlands, natural ridges, man-made navigation canals and flood protection infrastructure. Since 1900 and prior to the landfall of Hurricane Katrina in 2005, Louisiana lost approximately 480,000 ha (1,850 sq mi) of coastal wetlands and an additional 20,000 ha (77 sq mi) due to Katrina. This resulted in a total wetland storm protection value loss of USD 28.3 billion and USD 1.1 billion, respectively (Costanza 2008). To investigate the response of hurricane storm surge (e.g. peak water levels, inundation time and extent) through time due to land loss, hydrodynamic models that represent historical eras of the Louisiana coastal landscape were developed. Land:Water (L:W) isopleths (Gagliano 1970, 1971, Twilley 2016) have been calculated along the coast from the Sabine River to the Pearl River. These isopleths were utilized to create a simplified coastal landscape (bathymetry, topography, bottom roughness) representing circa 2010. Similar methodologies are employed with the objective of developing storm surge models that represent the coastal landscape for past eras. The goal is to temporally examine the evolution of storm surge along coastal Louisiana. The isopleths determined to best represent the Louisiana coast as a result of the methodology devised to develop the simple storm surge model for c.2010 are applied in the development of surge models for historical eras c.1930 and c.1970. The ADvaced CIRCulation (ADCIRC) code (Luettich 2004) is used to perform storm surge simulations with a predetermined suite of hurricane wind and pressure forcings. Hydrologic Unit Code 12 (HUC12) sub-watersheds provide geographical bounds to quantify mean maximum water surface elevations (WSEs), volume of inundation, and area of inundation. HUC12 sub-watersheds also provide a means to compare/contrast these quantified surge parameters on a HUC12-by-HUC12 basis for the c.1930, c.1970 and c.2010

Influence of potential sea level rise on societal vulnerability to hurricane storm-surge hazards, Sarasota County, Florida

Science.gov (United States)

Frazier, Tim G.; Wood, Nathan; Yarnal, Brent; Bauer, Denise H.

2010-01-01

Although the potential for hurricanes under current climatic conditions continue to threaten coastal communities, there is concern that climate change, specifically potential increases in sea level, could influence the impacts of future hurricanes. To examine the potential effect of sea level rise on community vulnerability to future hurricanes, we assess variations in socioeconomic exposure in Sarasota County, FL, to contemporary hurricane storm-surge hazards and to storm-surge hazards enhanced by sea level rise scenarios. Analysis indicates that significant portions of the population, economic activity, and critical facilities are in contemporary and future hurricane storm-surge hazard zones. The addition of sea level rise to contemporary storm-surge hazard zones effectively causes population and asset (infrastructure, natural resources, etc) exposure to be equal to or greater than what is in the hazard zone of the next higher contemporary Saffir–Simpson hurricane category. There is variability among communities for this increased exposure, with greater increases in socioeconomic exposure due to the addition of sea level rise to storm-surge hazard zones as one progresses south along the shoreline. Analysis of the 2050 comprehensive land use plan suggests efforts to manage future growth in residential, economic and infrastructure development in Sarasota County may increase societal exposure to hurricane storm-surge hazards.

Determining Storm Surge Return Periods: The Use of Evidence of Historic Events

DEFF Research Database (Denmark)

Madsen, Kristine S.; Sørensen, Carlo Sass; Schmith, Torben

for tide gauge measurements, with 120 years of data available for the calculations. However, the oldest of these tide gauge stations was set up after a major storm surge in 1872, and no events of similar severity have occurred since. Including the evidence of the historic events from the 18th century...... changes the return period statistics, with a best estimate of a 100 year event changing from 1.5 meters (Sørensen et al. 2013) to 2.6 [2.2 – 2.8] meters (present study) in Køge just south of Copenhagen. Thus, with the tide gauge-based statistics, the storm surge on January 4 2017 was a 100 year event......, but with the revised statistics using historic evidence, much larger events can be expected. Further, we assess the very large impact of sea level rise on the storm surge statistics. As an example, according to the official statistics of southern Copenhagen, the flooding of a present day 100 year event...

Storm surge in the Bay of Bengal and Arabian Sea: The problem and its prediction

Digital Repository Service at National Institute of Oceanography (India)

Dube, S.K.; Rao, A.D.; Sinha, P.C.; Murty, T.S.; Bahulayan, N.

to annual economic losses in these countries. Thus, the real time monitoring and warning of storm surge is of great concern for this region. The goal of this paper is to provide an overview of major aspects of the storm surge problem in the Bay of Bengal...

Storm surge modeling of Superstorm Sandy in the New York City Metropolitan area

Science.gov (United States)

Benimoff, A. I.; Blanton, B. O.; Dzedzits, E.; Fritz, W. J.; Kress, M.; Muzio, P.; Sela, L.

2013-12-01

Even though the New York/New Jersey area does not lie within the typical 'hurricane belt', recent events and the historical record indicate that large infrequent tropical storms have had direct hits on the region, with impacts being amplified due to the nearly right angle bend in the coastline. The recent plan unveiled by New York City's Mayor Bloomberg lays out mitigation strategies to protect the region's communities, infrastructure, and assets from future storms, and numerical simulation of storm surge and wave hazards driven by potential hurricanes plays a central role in developing and evaluating these strategies. To assist in local planning, recovery, and decision-making, we have used the tide, storm surge, and wind wave model ADCIRC+SWAN to simulate storm surge in one of the most populated areas of the United States: the New York City (NYC) metropolitan area. We have generated a new high-resolution triangular finite-element model grid for the region from recent USGS data as well as recent city topographic maps at 2-foot (0.6m) contour intervals, nautical charts, and details of shipping channels. Our hindcast simulations are compared against Superstorm Sandy. We used the City University of New York High Performance Computing Center's Cray XE6tm at the College of Staten Island for these simulations. Hindcasting and analysis of the Superstorm Sandy storm surge and waves indicates that our simulations produce a reasonable representation of actual events. The grid will be used in an ADCIRC-based forecasting system implementation for the region.

Predicting typhoon-induced storm surge tide with a two-dimensional hydrodynamic model and artificial neural network model

Science.gov (United States)

Chen, W.-B.; Liu, W.-C.; Hsu, M.-H.

2012-12-01

Precise predictions of storm surges during typhoon events have the necessity for disaster prevention in coastal seas. This paper explores an artificial neural network (ANN) model, including the back propagation neural network (BPNN) and adaptive neuro-fuzzy inference system (ANFIS) algorithms used to correct poor calculations with a two-dimensional hydrodynamic model in predicting storm surge height during typhoon events. The two-dimensional model has a fine horizontal resolution and considers the interaction between storm surges and astronomical tides, which can be applied for describing the complicated physical properties of storm surges along the east coast of Taiwan. The model is driven by the tidal elevation at the open boundaries using a global ocean tidal model and is forced by the meteorological conditions using a cyclone model. The simulated results of the hydrodynamic model indicate that this model fails to predict storm surge height during the model calibration and verification phases as typhoons approached the east coast of Taiwan. The BPNN model can reproduce the astronomical tide level but fails to modify the prediction of the storm surge tide level. The ANFIS model satisfactorily predicts both the astronomical tide level and the storm surge height during the training and verification phases and exhibits the lowest values of mean absolute error and root-mean-square error compared to the simulated results at the different stations using the hydrodynamic model and the BPNN model. Comparison results showed that the ANFIS techniques could be successfully applied in predicting water levels along the east coastal of Taiwan during typhoon events.

Improvements of Storm Surge Modelling in the Gulf of Venice with Satellite Data: The ESA Due Esurge-Venice Project

Science.gov (United States)

De Biasio, F.; Bajo, M.; Vignudelli, S.; Papa, A.; della Valle, A.; Umgiesser, G.; Donlon, C.; Zecchetto, S.

2016-08-01

Among the most detrimental natural phenomena, storm surges heavily endanger the environment, the economy and the everyday life of sea-side countries and coastal zones. Considering that 120.000.000 people live in the Mediterranean area, with additional 200.000.000 presences in Summer for tourism purposes, the correct prediction of storm surges is crucial to avoid fatalities and economic losses. Earth Observation (EO) can play an important role in operational storm surge forecasting, yet it is not widely diffused in the storm surge community. In 2011 the European Space Agency (ESA), through its Data User Element (DUE) programme, financed two projects aimed at encouraging the uptake of EO data in this sector: eSurge and eSurge-Venice (eSV). The former was intended to address the issues of a wider users' community, while the latter was focused on a restricted geographical area: the northern Adriatic Sea and the Gulf of Venice. Among the objectives of the two projects there were a number of storm surge hindcast experiments using satellite data, to demonstrate the improvements on the surge forecast brought by EO. We report here the results of the hindcast experiments of the eSV project. They were aimed to test the sensitivity of a storm surge model to a forcing wind field modified with scatterometer data in order to reduce the bias between simulated and observed winds. Hindcast experiments were also performed to test the response of the storm surge model to the assimilation, with a dual 4D-Var system, of satellite altimetry observations as model errors of the initial state of the sea surface level. Remarkable improvements on the storm surge forecast have been obtained for what concerns the modified model wind forcing. Encouraging results have been obtained also in the assimilation experiments.

Numerical modelling of tides and storm surges in the Bay of Bengal

Digital Repository Service at National Institute of Oceanography (India)

Sindhu, B.

were done. A storm surge model was developed to simulate total water levels and derived surges caused by low pressure systems identified during the past 27 years (1974-2000) in the Bay of Bengal. Study also estimated the return levels of extreme sea...

Model simulation of storm surge potential for Andaman islands

Digital Repository Service at National Institute of Oceanography (India)

Kumar, V.S.; RameshBabu, V.; Babu, M.T.; Dhinakaran, G.; Rajamanickam, G.V.

Hydraulics and Oceanography, the Hydrodynamics Module Reference Manual. DHI Water and Environment, Horsholm, Denmark, 58 p. Dube, S.K., Sinha, P C , Rao, A.D., and Rao, G.S., 1985. Numerical modeling of storm surges in the Arabian Sea, Appl. Math Modelling, 9...

Artificial Neural Network forecasting of storm surge water levels at major estuarine ports to supplement national tide-surge models and improve port resilience planning

Science.gov (United States)

French, Jon; Mawdsley, Robert; Fujiyama, Taku; Achuthan, Kamal

2017-04-01

Effective prediction of tidal storm surge is of considerable importance for operators of major ports, since much of their infrastructure is necessarily located close to sea level. Storm surge inundation can damage critical elements of this infrastructure and significantly disrupt port operations and downstream supply chains. The risk of surge inundation is typically approached using extreme value analysis, while short-term forecasting generally relies on coastal shelf-scale tide and surge models. However, extreme value analysis does not provide information on the duration of a surge event and can be sensitive to the assumptions made and the historic data available. Also, whilst regional tide and surge models perform well along open coasts, their fairly coarse spatial resolution means that they do not always provide accurate predictions for estuarine ports. As part of a NERC Environmental Risks to Infrastructure Innovation Programme project, we have developed a tool that is specifically designed to forecast the North Sea storm surges on major ports along the east coast of the UK. Of particular interest is the Port of Immingham, Humber estuary, which handles the largest volume of bulk cargo in the UK including major flows of coal and biomass for power generation. A tidal surge in December 2013, with an estimated return period of 760 years, partly flooded the port, damaged infrastructure and disrupted operations for several weeks. This and other recent surge events highlight the need for additional tools to supplement the national UK Storm Tide Warning Service. Port operators are also keen to have access to less computationally expensive forecasting tools for scenario planning and to improve their resilience to actual events. In this paper, we demonstrate the potential of machine learning methods based on Artificial Neural Networks (ANNs) to generate accurate short-term forecasts of extreme water levels at estuarine North Sea ports such as Immingham. An ANN is

Catastrophe loss modelling of storm-surge flood risk in eastern England.

Science.gov (United States)

Muir Wood, Robert; Drayton, Michael; Berger, Agnete; Burgess, Paul; Wright, Tom

2005-06-15

Probabilistic catastrophe loss modelling techniques, comprising a large stochastic set of potential storm-surge flood events, each assigned an annual rate of occurrence, have been employed for quantifying risk in the coastal flood plain of eastern England. Based on the tracks of the causative extratropical cyclones, historical storm-surge events are categorized into three classes, with distinct windfields and surge geographies. Extreme combinations of "tide with surge" are then generated for an extreme value distribution developed for each class. Fragility curves are used to determine the probability and magnitude of breaching relative to water levels and wave action for each section of sea defence. Based on the time-history of water levels in the surge, and the simulated configuration of breaching, flow is time-stepped through the defences and propagated into the flood plain using a 50 m horizontal-resolution digital elevation model. Based on the values and locations of the building stock in the flood plain, losses are calculated using vulnerability functions linking flood depth and flood velocity to measures of property loss. The outputs from this model for a UK insurance industry portfolio include "loss exceedence probabilities" as well as "average annualized losses", which can be employed for calculating coastal flood risk premiums in each postcode.

The effect of wave current interactions on the storm surge and inundation in Charleston Harbor during Hurricane Hugo 1989

Science.gov (United States)

Xie, Lian; Liu, Huiqing; Peng, Machuan

The effects of wave-current interactions on the storm surge and inundation induced by Hurricane Hugo in and around the Charleston Harbor and its adjacent coastal regions are examined by using a three-dimensional (3-D) wave-current coupled modeling system. The 3-D storm surge and inundation modeling component of the coupled system is based on the Princeton ocean model (POM), whereas the wave modeling component is based on the third-generation wave model, simulating waves nearshore (SWAN). The results indicate that the effects of wave-induced surface, bottom, and radiation stresses can separately or in combination produce significant changes in storm surge and inundation. The effects of waves vary spatially. In some areas, the contribution of waves to peak storm surge during Hurricane Hugo reached as high as 0.76 m which led to substantial changes in the inundation and drying areas simulated by the storm surge model.

Storm surges-An option for Hamburg, Germany, to mitigate expected future aggravation of risk

International Nuclear Information System (INIS)

Storch, Hans von; Goennert, Gabriele; Meine, Manfred

2008-01-01

Summary: Rising sea level together with regionally increased storm activity, caused by elevated and increasing levels of greenhouse gases in the atmosphere will in many parts of the world increase the risk of storm surges significantly. Reducing the emissions of greenhouse gases into the atmosphere may mitigate the increasing risks somewhat, but the major task for regional and local stakeholders will be to prepare for appropriate adaptation. In most cases, possible strategies include intensification of coastal defense measures, in particular strengthening dykes, and adaptation to intermittent flooding. In case of Hamburg and the tidal Elbe river a third option seems to be available, which aims at mitigating storm surge risks by applying estuary engineering constructions. This option is sketched in this paper. The option has the potential to significantly reduce the expected future increases of local surge heights

Verification of an ensemble prediction system for storm surge forecast in the Adriatic Sea

Science.gov (United States)

Mel, Riccardo; Lionello, Piero

2014-12-01

In the Adriatic Sea, storm surges present a significant threat to Venice and to the flat coastal areas of the northern coast of the basin. Sea level forecast is of paramount importance for the management of daily activities and for operating the movable barriers that are presently being built for the protection of the city. In this paper, an EPS (ensemble prediction system) for operational forecasting of storm surge in the northern Adriatic Sea is presented and applied to a 3-month-long period (October-December 2010). The sea level EPS is based on the HYPSE (hydrostatic Padua Sea elevation) model, which is a standard single-layer nonlinear shallow water model, whose forcings (mean sea level pressure and surface wind fields) are provided by the ensemble members of the ECMWF (European Center for Medium-Range Weather Forecasts) EPS. Results are verified against observations at five tide gauges located along the Croatian and Italian coasts of the Adriatic Sea. Forecast uncertainty increases with the predicted value of the storm surge and with the forecast lead time. The EMF (ensemble mean forecast) provided by the EPS has a rms (root mean square) error lower than the DF (deterministic forecast), especially for short (up to 3 days) lead times. Uncertainty for short lead times of the forecast and for small storm surges is mainly caused by uncertainty of the initial condition of the hydrodynamical model. Uncertainty for large lead times and large storm surges is mainly caused by uncertainty in the meteorological forcings. The EPS spread increases with the rms error of the forecast. For large lead times the EPS spread and the forecast error substantially coincide. However, the EPS spread in this study, which does not account for uncertainty in the initial condition, underestimates the error during the early part of the forecast and for small storm surge values. On the contrary, it overestimates the rms error for large surge values. The PF (probability forecast) of the EPS

Automating Flood Hazard Mapping Methods for Near Real-time Storm Surge Inundation and Vulnerability Assessment

Science.gov (United States)

Weigel, A. M.; Griffin, R.; Gallagher, D.

2015-12-01

Storm surge has enough destructive power to damage buildings and infrastructure, erode beaches, and threaten human life across large geographic areas, hence posing the greatest threat of all the hurricane hazards. The United States Gulf of Mexico has proven vulnerable to hurricanes as it has been hit by some of the most destructive hurricanes on record. With projected rises in sea level and increases in hurricane activity, there is a need to better understand the associated risks for disaster mitigation, preparedness, and response. GIS has become a critical tool in enhancing disaster planning, risk assessment, and emergency response by communicating spatial information through a multi-layer approach. However, there is a need for a near real-time method of identifying areas with a high risk of being impacted by storm surge. Research was conducted alongside Baron, a private industry weather enterprise, to facilitate automated modeling and visualization of storm surge inundation and vulnerability on a near real-time basis. This research successfully automated current flood hazard mapping techniques using a GIS framework written in a Python programming environment, and displayed resulting data through an Application Program Interface (API). Data used for this methodology included high resolution topography, NOAA Probabilistic Surge model outputs parsed from Rich Site Summary (RSS) feeds, and the NOAA Census tract level Social Vulnerability Index (SoVI). The development process required extensive data processing and management to provide high resolution visualizations of potential flooding and population vulnerability in a timely manner. The accuracy of the developed methodology was assessed using Hurricane Isaac as a case study, which through a USGS and NOAA partnership, contained ample data for statistical analysis. This research successfully created a fully automated, near real-time method for mapping high resolution storm surge inundation and vulnerability for the

Predicting the Storm Surge Threat of Hurricane Sandy with the National Weather Service SLOSH Model

Directory of Open Access Journals (Sweden)

Cristina Forbes

2014-05-01

Full Text Available Numerical simulations of the storm tide that flooded the US Atlantic coastline during Hurricane Sandy (2012 are carried out using the National Weather Service (NWS Sea Lakes and Overland Surges from Hurricanes (SLOSH storm surge prediction model to quantify its ability to replicate the height, timing, evolution and extent of the water that was driven ashore by this large, destructive storm. Recent upgrades to the numerical model, including the incorporation of astronomical tides, are described and simulations with and without these upgrades are contrasted to assess their contributions to the increase in forecast accuracy. It is shown, through comprehensive verifications of SLOSH simulation results against peak water surface elevations measured at the National Oceanic and Atmospheric Administration (NOAA tide gauge stations, by storm surge sensors deployed and hundreds of high water marks collected by the U.S. Geological Survey (USGS, that the SLOSH-simulated water levels at 71% (89% of the data measurement locations have less than 20% (30% relative error. The RMS error between observed and modeled peak water levels is 0.47 m. In addition, the model’s extreme computational efficiency enables it to run large, automated ensembles of predictions in real-time to account for the high variability that can occur in tropical cyclone forecasts, thus furnishing a range of values for the predicted storm surge and inundation threat.

Using wind setdown and storm surge on Lake Erie to calibrate the air-sea drag coefficient.

Science.gov (United States)

Drews, Carl

2013-01-01

The air-sea drag coefficient controls the transfer of momentum from wind to water. In modeling storm surge, this coefficient is a crucial parameter for estimating the surge height. This study uses two strong wind events on Lake Erie to calibrate the drag coefficient using the Coupled Ocean Atmosphere Wave Sediment Transport (COAWST) modeling system and the the Regional Ocean Modeling System (ROMS). Simulated waves are generated on the lake with Simulating WAves Nearshore (SWAN). Wind setdown provides the opportunity to eliminate wave setup as a contributing factor, since waves are minimal at the upwind shore. The study finds that model results significantly underestimate wind setdown and storm surge when a typical open-ocean formulation without waves is used for the drag coefficient. The contribution of waves to wind setdown and storm surge is 34.7%. Scattered lake ice also increases the effective drag coefficient by a factor of 1.1.

A parabolic model of drag coefficient for storm surge simulation in the South China Sea

Science.gov (United States)

Peng, Shiqiu; Li, Yineng

2015-01-01

Drag coefficient (Cd) is an essential metric in the calculation of momentum exchange over the air-sea interface and thus has large impacts on the simulation or forecast of the upper ocean state associated with sea surface winds such as storm surges. Generally, Cd is a function of wind speed. However, the exact relationship between Cd and wind speed is still in dispute, and the widely-used formula that is a linear function of wind speed in an ocean model could lead to large bias at high wind speed. Here we establish a parabolic model of Cd based on storm surge observations and simulation in the South China Sea (SCS) through a number of tropical cyclone cases. Simulation of storm surges for independent Tropical cyclones (TCs) cases indicates that the new parabolic model of Cd outperforms traditional linear models. PMID:26499262

A parabolic model of drag coefficient for storm surge simulation in the South China Sea

Science.gov (United States)

Peng, Shiqiu; Li, Yineng

2015-10-01

Drag coefficient (Cd) is an essential metric in the calculation of momentum exchange over the air-sea interface and thus has large impacts on the simulation or forecast of the upper ocean state associated with sea surface winds such as storm surges. Generally, Cd is a function of wind speed. However, the exact relationship between Cd and wind speed is still in dispute, and the widely-used formula that is a linear function of wind speed in an ocean model could lead to large bias at high wind speed. Here we establish a parabolic model of Cd based on storm surge observations and simulation in the South China Sea (SCS) through a number of tropical cyclone cases. Simulation of storm surges for independent Tropical cyclones (TCs) cases indicates that the new parabolic model of Cd outperforms traditional linear models.

Modeling Tropical Cyclone Storm Surge and Wind Induced Risk Along the Bay of Bengal Coastline Using a Statistical Copula

Science.gov (United States)

Bushra, N.; Trepanier, J. C.; Rohli, R. V.

2017-12-01

High winds, torrential rain, and storm surges from tropical cyclones (TCs) cause massive destruction to property and cost the lives of many people. The coastline of the Bay of Bengal (BoB) ranks as one of the most susceptible to TC storm surges in the world due to low-lying elevation and a high frequency of occurrence. Bangladesh suffers the most due to its geographical setting and population density. Various models have been developed to predict storm surge in this region but none of them quantify statistical risk with empirical data. This study describes the relationship and dependency between empirical TC storm surge and peak reported wind speed at the BoB using a bivariate statistical copula and data from 1885-2011. An Archimedean, Gumbel copula with margins defined by the empirical distributions is specified as the most appropriate choice for the BoB. The model provides return periods for pairs of TC storm surge and peak wind along the BoB coastline. The BoB can expect a TC with peak reported winds of at least 24 m s-1 and surge heights of at least 4.0 m, on average, once every 3.2 years, with a quartile pointwise confidence interval of 2.7-3.8 years. In addition, the BoB can expect peak reported winds of 62 m s-1 and surge heights of at least 8.0 m, on average, once every 115.4 years, with a quartile pointwise confidence interval of 55.8-381.1 years. The purpose of the analysis is to increase the understanding of these dangerous TC characteristics to reduce fatalities and monetary losses into the future. Application of the copula will mitigate future threats of storm surge impacts on coastal communities of the BoB.

Using 18th century storm-surge data from the Dutch Coast to improve the confidence in flood-risk estimates

Directory of Open Access Journals (Sweden)

F. Baart

2011-10-01

Full Text Available For the design of cost-effective coastal defence a precise estimate is needed of the 1/10 000 per year storm surge. A more precise estimate requires more observations. Therefore, the three greatest storm surges that hit the northern part of the Holland Coast in the 18th century are reconstructed. The reconstructions are based on paintings, drawings, written records and shell deposits that have recently appeared. The storm-surge levels of these storms have been estimated using numerical modelling of the coastal processes. Here we show how these reconstructions can be used in combination with extreme value statistics to give a more confident estimate of low probability events.

Effects of wave-current interaction on storm surge in the Taiwan Strait: Insights from Typhoon Morakot

Science.gov (United States)

Yu, Xiaolong; Pan, Weiran; Zheng, Xiangjing; Zhou, Shenjie; Tao, Xiaoqin

2017-08-01

The effects of wave-current interaction on storm surge are investigated by a two-dimensional wave-current coupling model through simulations of Typhoon Morakot in the Taiwan Strait. The results show that wind wave and slope of sea floor govern wave setup modulations within the nearshore surf zone. Wave setup during Morakot can contribute up to 24% of the total storm surge with a maximum value of 0.28 m. The large wave setup commonly coincides with enhanced radiation stress gradient, which is itself associated with transfer of wave momentum flux. Water levels are to leading order in modulating significant wave height inside the estuary. High water levels due to tidal change and storm surge stabilize the wind wave and decay wave breaking. Outside of the estuary, waves are mainly affected by the current-induced modification of wind energy input to the wave generation. By comparing the observed significant wave height and water level with the results from uncoupled and coupled simulations, the latter shows a better agreement with the observations. It suggests that wave-current interaction plays an important role in determining the extreme storm surge and wave height in the study area and should not be neglected in a typhoon forecast.

The Development of High-speed Full-function Storm Surge Model and the Case Study of 2013 Typhoon Haiyan

Science.gov (United States)

Tsai, Y. L.; Wu, T. R.; Lin, C. Y.; Chuang, M. H.; Lin, C. W.

2016-02-01

An ideal storm surge operational model should feature as: 1. Large computational domain which covers the complete typhoon life cycle. 2. Supporting both parametric and atmospheric models. 3. Capable of calculating inundation area for risk assessment. 4. Tides are included for accurate inundation simulation. Literature review shows that not many operational models reach the goals for the fast calculation, and most of the models have limited functions. In this paper, a well-developed COMCOT (COrnell Multi-grid Coupled of Tsunami Model) tsunami model is chosen as the kernel to establish a storm surge model which solves the nonlinear shallow water equations on both spherical and Cartesian coordinates directly. The complete evolution of storm surge including large-scale propagation and small-scale offshore run-up can be simulated by nested-grid scheme. The global tide model TPXO 7.2 established by Oregon State University is coupled to provide astronomical boundary conditions. The atmospheric model named WRF (Weather Research and Forecasting Model) is also coupled to provide metrological fields. The high-efficiency thin-film method is adopted to evaluate the storm surge inundation. Our in-house model has been optimized by OpenMp (Open Multi-Processing) with the performance which is 10 times faster than the original version and makes it an early-warning storm surge model. In this study, the thorough simulation of 2013 Typhoon Haiyan is performed. The detailed results will be presented in Oceanic Science Meeting of 2016 in terms of surge propagation and high-resolution inundation areas.

The combined risk of extreme tropical cyclone winds and storm surges along the U.S. Gulf of Mexico Coast

Science.gov (United States)

Trepanier, J. C.; Yuan, J.; Jagger, T. H.

2017-03-01

Tropical cyclones, with their nearshore high wind speeds and deep storm surges, frequently strike the United States Gulf of Mexico coastline influencing millions of people and disrupting offshore economic activities. The combined risk of occurrence of tropical cyclone nearshore wind speeds and storm surges is assessed at 22 coastal cities throughout the United States Gulf of Mexico. The models used are extreme value copulas fitted with margins defined by the generalized Pareto distribution or combinations of Weibull, gamma, lognormal, or normal distributions. The statistical relationships between the nearshore wind speed and storm surge are provided for each coastal city prior to the copula model runs using Spearman's rank correlations. The strongest significant relationship between the nearshore wind speed and storm surge exists at Shell Beach, LA (ρ = 0.67), followed by South Padre Island, TX (ρ = 0.64). The extreme value Archimedean copula models for each city then provide return periods for specific nearshore wind speed and storm surge pairs. Of the 22 cities considered, Bay St. Louis, MS, has the shortest return period for a tropical cyclone with at least a 50 ms-1 nearshore wind speed and a 3 m surge (19.5 years, 17.1-23.5). The 90% confidence intervals are created by recalculating the return periods for a fixed set of wind speeds and surge levels using 100 samples of the model parameters. The results of this study can be utilized by policy managers and government officials concerned with coastal populations and economic activity in the Gulf of Mexico.

Assessing storm surge hazard and impact of sea level rise in the Lesser Antilles case study of Martinique

Science.gov (United States)

Krien, Yann; Dudon, Bernard; Roger, Jean; Arnaud, Gael; Zahibo, Narcisse

2017-09-01

In the Lesser Antilles, coastal inundations from hurricane-induced storm surges pose a great threat to lives, properties and ecosystems. Assessing current and future storm surge hazards with sufficient spatial resolution is of primary interest to help coastal planners and decision makers develop mitigation and adaptation measures. Here, we use wave-current numerical models and statistical methods to investigate worst case scenarios and 100-year surge levels for the case study of Martinique under present climate or considering a potential sea level rise. Results confirm that the wave setup plays a major role in the Lesser Antilles, where the narrow island shelf impedes the piling-up of large amounts of wind-driven water on the shoreline during extreme events. The radiation stress gradients thus contribute significantly to the total surge - up to 100 % in some cases. The nonlinear interactions of sea level rise (SLR) with bathymetry and topography are generally found to be relatively small in Martinique but can reach several tens of centimeters in low-lying areas where the inundation extent is strongly enhanced compared to present conditions. These findings further emphasize the importance of waves for developing operational storm surge warning systems in the Lesser Antilles and encourage caution when using static methods to assess the impact of sea level rise on storm surge hazard.

Building with Nature: in search of resilient storm surge protection strategies

NARCIS (Netherlands)

Slobbe, van E.J.J.; Vriend, de H.J.; Aarninkhof, S.G.J.; Lulofs, K.; Vries, de M.; Dircke, P.

2013-01-01

Low-lying, densely populated coastal areas worldwide are under threat, requiring coastal managers to develop new strategies to cope with land subsidence, sea-level rise and the increasing risk of storm-surge-induced floods. Traditional engineering approaches optimizing for safety are often

Assessing and Mitigating Hurricane Storm Surge Risk in a Changing Environment

Science.gov (United States)

Lin, N.; Shullman, E.; Xian, S.; Feng, K.

2017-12-01

Hurricanes have induced devastating storm surge flooding worldwide. The impacts of these storms may worsen in the coming decades because of rapid coastal development coupled with sea-level rise and possibly increasing storm activity due to climate change. Major advances in coastal flood risk management are urgently needed. We present an integrated dynamic risk analysis for flooding task (iDraft) framework to assess and manage coastal flood risk at the city or regional scale, considering integrated dynamic effects of storm climatology change, sea-level rise, and coastal development. We apply the framework to New York City. First, we combine climate-model projected storm surge climatology and sea-level rise with engineering- and social/economic-model projected coastal exposure and vulnerability to estimate the flood damage risk for the city over the 21st century. We derive temporally-varying risk measures such as the annual expected damage as well as temporally-integrated measures such as the present value of future losses. We also examine the individual and joint contributions to the changing risk of the three dynamic factors (i.e., sea-level rise, storm change, and coastal development). Then, we perform probabilistic cost-benefit analysis for various coastal flood risk mitigation strategies for the city. Specifically, we evaluate previously proposed mitigation measures, including elevating houses on the floodplain and constructing flood barriers at the coast, by comparing their estimated cost and probability distribution of the benefit (i.e., present value of avoided future losses). We also propose new design strategies, including optimal design (e.g., optimal house elevation) and adaptive design (e.g., flood protection levels that are designed to be modified over time in a dynamic and uncertain environment).

Purple pitcher plant (Sarracenia rosea Dieback and partial community disassembly following experimental storm surge in a coastal pitcher plant bog.

Directory of Open Access Journals (Sweden)

Matthew J Abbott

Full Text Available Sea-level rise and frequent intense hurricanes associated with climate change will result in recurrent flooding of inland systems such as Gulf Coastal pitcher plant bogs by storm surges. These surges can transport salt water and sediment to freshwater bogs, greatly affecting their biological integrity. Purple pitcher plants (Sarracenia rosea are Gulf Coast pitcher plant bog inhabitants that could be at a disadvantage under this scenario because their pitcher morphology may leave them prone to collection of saline water and sediment after a surge. We investigated the effects of storm surge water salinity and sediment type on S. rosea vitality, plant community structure, and bog soil-water conductivity. Plots (containing ≥1 ramet of S. rosea were experimentally flooded with fresh or saline water crossed with one of three sediment types (local, foreign, or no sediment. There were no treatment effects on soil-water conductivity; nevertheless, direct exposure to saline water resulted in significantly lower S. rosea cover until the following season when a prescribed fire and regional drought contributed to the decline of all the S. rosea to near zero percent cover. There were also significant differences in plant community structure between treatments over time, reflecting how numerous species increased in abundance and a few species decreased in abundance. However, in contrast to S. rosea, most of the other species in the community appeared resilient to the effects of storm surge. Thus, although the community may be somewhat affected by storm surge, those few species that are particularly sensitive to the storm surge disturbance will likely drop out of the community and be replaced by more resilient species. Depending on the longevity of these biological legacies, Gulf Coastal pitcher plant bogs may be incapable of fully recovering if they become exposed to storm surge more frequently due to climate change.

Improving Short-Range Ensemble Kalman Storm Surge Forecasting Using Robust Adaptive Inflation

KAUST Repository

Altaf, Muhammad

2013-08-01

This paper presents a robust ensemble filtering methodology for storm surge forecasting based on the singular evolutive interpolated Kalman (SEIK) filter, which has been implemented in the framework of the H∞ filter. By design, an H∞ filter is more robust than the common Kalman filter in the sense that the estimation error in the H∞ filter has, in general, a finite growth rate with respect to the uncertainties in assimilation. The computational hydrodynamical model used in this study is the Advanced Circulation (ADCIRC) model. The authors assimilate data obtained from Hurricanes Katrina and Ike as test cases. The results clearly show that the H∞-based SEIK filter provides more accurate short-range forecasts of storm surge compared to recently reported data assimilation results resulting from the standard SEIK filter.

Improving Short-Range Ensemble Kalman Storm Surge Forecasting Using Robust Adaptive Inflation

KAUST Repository

Altaf, Muhammad; Butler, T.; Luo, X.; Dawson, C.; Mayo, T.; Hoteit, Ibrahim

2013-01-01

This paper presents a robust ensemble filtering methodology for storm surge forecasting based on the singular evolutive interpolated Kalman (SEIK) filter, which has been implemented in the framework of the H∞ filter. By design, an H∞ filter is more robust than the common Kalman filter in the sense that the estimation error in the H∞ filter has, in general, a finite growth rate with respect to the uncertainties in assimilation. The computational hydrodynamical model used in this study is the Advanced Circulation (ADCIRC) model. The authors assimilate data obtained from Hurricanes Katrina and Ike as test cases. The results clearly show that the H∞-based SEIK filter provides more accurate short-range forecasts of storm surge compared to recently reported data assimilation results resulting from the standard SEIK filter.

Hybrid vs Adaptive Ensemble Kalman Filtering for Storm Surge Forecasting

Science.gov (United States)

Altaf, M. U.; Raboudi, N.; Gharamti, M. E.; Dawson, C.; McCabe, M. F.; Hoteit, I.

2014-12-01

Recent storm surge events due to Hurricanes in the Gulf of Mexico have motivated the efforts to accurately forecast water levels. Toward this goal, a parallel architecture has been implemented based on a high resolution storm surge model, ADCIRC. However the accuracy of the model notably depends on the quality and the recentness of the input data (mainly winds and bathymetry), model parameters (e.g. wind and bottom drag coefficients), and the resolution of the model grid. Given all these uncertainties in the system, the challenge is to build an efficient prediction system capable of providing accurate forecasts enough ahead of time for the authorities to evacuate the areas at risk. We have developed an ensemble-based data assimilation system to frequently assimilate available data into the ADCIRC model in order to improve the accuracy of the model. In this contribution we study and analyze the performances of different ensemble Kalman filter methodologies for efficient short-range storm surge forecasting, the aim being to produce the most accurate forecasts at the lowest possible computing time. Using Hurricane Ike meteorological data to force the ADCIRC model over a domain including the Gulf of Mexico coastline, we implement and compare the forecasts of the standard EnKF, the hybrid EnKF and an adaptive EnKF. The last two schemes have been introduced as efficient tools for enhancing the behavior of the EnKF when implemented with small ensembles by exploiting information from a static background covariance matrix. Covariance inflation and localization are implemented in all these filters. Our results suggest that both the hybrid and the adaptive approach provide significantly better forecasts than those resulting from the standard EnKF, even when implemented with much smaller ensembles.

A Comparison of Ensemble Kalman Filters for Storm Surge Assimilation

KAUST Repository

Altaf, Muhammad

2014-08-01

This study evaluates and compares the performances of several variants of the popular ensembleKalman filter for the assimilation of storm surge data with the advanced circulation (ADCIRC) model. Using meteorological data from Hurricane Ike to force the ADCIRC model on a domain including the Gulf ofMexico coastline, the authors implement and compare the standard stochastic ensembleKalman filter (EnKF) and three deterministic square root EnKFs: the singular evolutive interpolated Kalman (SEIK) filter, the ensemble transform Kalman filter (ETKF), and the ensemble adjustment Kalman filter (EAKF). Covariance inflation and localization are implemented in all of these filters. The results from twin experiments suggest that the square root ensemble filters could lead to very comparable performances with appropriate tuning of inflation and localization, suggesting that practical implementation details are at least as important as the choice of the square root ensemble filter itself. These filters also perform reasonably well with a relatively small ensemble size, whereas the stochastic EnKF requires larger ensemble sizes to provide similar accuracy for forecasts of storm surge.

A Comparison of Ensemble Kalman Filters for Storm Surge Assimilation

KAUST Repository

Altaf, Muhammad; Butler, T.; Mayo, T.; Luo, X.; Dawson, C.; Heemink, A. W.; Hoteit, Ibrahim

2014-01-01

This study evaluates and compares the performances of several variants of the popular ensembleKalman filter for the assimilation of storm surge data with the advanced circulation (ADCIRC) model. Using meteorological data from Hurricane Ike to force the ADCIRC model on a domain including the Gulf ofMexico coastline, the authors implement and compare the standard stochastic ensembleKalman filter (EnKF) and three deterministic square root EnKFs: the singular evolutive interpolated Kalman (SEIK) filter, the ensemble transform Kalman filter (ETKF), and the ensemble adjustment Kalman filter (EAKF). Covariance inflation and localization are implemented in all of these filters. The results from twin experiments suggest that the square root ensemble filters could lead to very comparable performances with appropriate tuning of inflation and localization, suggesting that practical implementation details are at least as important as the choice of the square root ensemble filter itself. These filters also perform reasonably well with a relatively small ensemble size, whereas the stochastic EnKF requires larger ensemble sizes to provide similar accuracy for forecasts of storm surge.

Observing storm surges in the Bay of Bengal from satellite altimetry

Digital Repository Service at National Institute of Oceanography (India)

Antony, C.; Testut, L.; Unnikrishnan, A.S.

with the large tidal ranges give rise to extreme sea level in the head bay and surrounding regions. Moreover, low-lying nature of the coast and the dense population in the region make the coasts of the northern Bay of Bengal highly vulnerable to storm surges...-gauge data during the passage of the hurricane Igor that crossed Newfoundland in 2010. For this event, St. John’s tide gauge recorded a maximum surge of 94 cm and Jason-2 (the track located 89 km away from the tide-gauge station) showed positive sea-level...

A Tsunami Ball Approach to Storm Surge and Inundation: Application to Hurricane Katrina, 2005

Directory of Open Access Journals (Sweden)

Steven N. Ward

2009-01-01

Full Text Available Most analyses of storm surge and inundation solve equations of continuity and momentum on fixed finite-difference/finite-element meshes. I develop a completely new approach that uses a momentum equation to accelerate bits or balls of water over variable depth topography. The thickness of the water column at any point equals the volume density of balls there. In addition to being more intuitive than traditional methods, the tsunami ball approach has several advantages. (a By tracking water balls of fixed volume, the continuity equation is satisfied automatically and the advection term in the momentum equation becomes unnecessary. (b The procedure is meshless in the finite-difference/finite-element sense. (c Tsunami balls care little if they find themselves in the ocean or inundating land. (d Tsunami ball calculations of storm surge can be done on a laptop computer. I demonstrate and calibrate the method by simulating storm surge and inundation around New Orleans, Louisiana caused by Hurricane Katrina in 2005 and by comparing model predictions with field observations. To illustrate the flexibility of the tsunami ball technique, I run two “What If” hurricane scenarios—Katrina over Savannah, Georgia and Katrina over Cape Cod, Massachusetts.

Using 18th century storm-surge data from the Dutch Coast to improve the confidence in flood-risk estimates

NARCIS (Netherlands)

Baart, F.; Bakker, M.A.J.; Van Dongeren, A.; Den Heijer, C.; Van Heteren, S.; Smit, M.W.J.; Van Koningsveld, M.; Pool, A.

2011-01-01

For the design of cost-effective coastal defence a precise estimate is needed of the 1/10 000 per year storm surge. A more precise estimate requires more observations. Therefore, the three greatest storm surges that hit the northern part of the Holland Coast in the 18th century are reconstructed.

Directional analysis of the storm surge from Hurricane Sandy 2012, with applications to Charleston, New Orleans, and the Philippines.

Science.gov (United States)

Drews, Carl; Galarneau, Thomas J

2015-01-01

Hurricane Sandy in late October 2012 drove before it a storm surge that rose to 4.28 meters above mean lower low water at The Battery in lower Manhattan, and flooded the Hugh L. Carey automobile tunnel between Brooklyn and The Battery. This study examines the surge event in New York Harbor using the Weather Research and Forecasting (WRF) atmospheric model and the Coupled-Ocean-Atmosphere-Wave- Sediment Transport/Regional Ocean Modeling System (COAWST/ROMS). We present a new technique using directional analysis to calculate and display maps of a coastline's potential for storm surge; these maps are constructed from wind fields blowing from eight fixed compass directions. This analysis approximates the surge observed during Hurricane Sandy. The directional analysis is then applied to surge events at Charleston, South Carolina, New Orleans, Louisiana, and Tacloban City, the Philippines. Emergency managers could use these directional maps to prepare their cities for an approaching storm, on planning horizons from days to years.

Hindcast and validation of Hurricane Ike waves, forerunner, and storm surge

NARCIS (Netherlands)

Hope, M.E.; Westerink, J.J.; Kennedy, A.B.; Kerr, P.C.; Dietrich, J.C.; Dawson, C.; Bender, C.J.; Smith, J.M.; Jensen, R.E.; Zijlema, M.; Holthuijsen, L.H.; Luettich, R.A.; Powell, M.D.; Cardone, V.J.; Cox, A.T.; Pourtaheri, H.; Roberts, H.J.; Atkinson, J.H.; Tanaka, S.; Westerink, H.J.; Westerink, L.G.

2013-01-01

Hurricane Ike (2008) made landfall near Galveston, Texas, as a moderate intensity storm. Its large wind field in conjunction with the Louisiana-Texas coastline's broad shelf and large scale concave geometry generated waves and surge that impacted over 1000 km of coastline. Ike's complex and varied

Ebb-tidal delta morphology in response to a storm surge barrier

NARCIS (Netherlands)

Eelkema, M.; Wang, Z.B.; Hibma, A.

2012-01-01

The Eastern Scheldt ebb-tidal delta morphology has been adapting for the past 25 years in response to the construction of the Eastern Scheldt storm-surge barrier in 1986. As a result of the barrier, there has been a decrease in tidal amplitudes, volumes, and average flow velocities, and there is

Vulnerability of Coastal Communities from Storm Surge and Flood Disasters

Science.gov (United States)

Bathi, Jejal Reddy; Das, Himangshu S.

2016-01-01

Disasters in the form of coastal storms and hurricanes can be very destructive. Preparing for anticipated effects of such disasters can help reduce the public health and economic burden. Identifying vulnerable population groups can help prioritize resources for the most needed communities. This paper presents a quantitative framework for vulnerability measurement that incorporates both socioeconomic and flood inundation vulnerability. The approach is demonstrated for three coastal communities in Mississippi with census tracts being the study unit. The vulnerability results are illustrated as thematic maps for easy usage by planners and emergency responders to assist in prioritizing their actions to vulnerable populations during storm surge and flood disasters. PMID:26907313

Modelling the effects of tides and storm surges on coastal aquifers using a coupled surface-subsurface approach.

Science.gov (United States)

Yang, Jie; Graf, Thomas; Herold, Maria; Ptak, Thomas

2013-06-01

Coastal aquifers are complex hydrologic systems because many physical processes interact: (i) variably saturated flow, (ii) spatial-temporal fluid density variations, (iii) tidal fluctuations, (iv) storm surges overtopping dykes, and (v) surface runoff of storm water. The HydroGeoSphere model is used to numerically simulate coastal flow dynamics, assuming a fully coupled surface-subsurface approach, accounting for all processes listed above. The diffusive wave approximation of the St. Venant equation is used to describe surface flow. Surface flow and salt transport are fully coupled with subsurficial variably saturated, variable-density flow and salt transport through mathematical terms that represent exchange of fluid mass and solute mass, respectively. Tides and storm surges induce a time-variant head that is applied to nodes of the surface domain. The approach is applied to real cases of tide and storm surge events. Tide simulation results confirm the existence of a recirculating zone, forming beneath the upper part of the intertidal zone. By monitoring the exchange fluid flux rates through the beach, it was found that the major inflow to the aquifer takes place at the upper part of the intertidal zone, which explains the formation of the recirculating zone. The recirculating zone is forming particularly during rising tide. Results from a storm surge simulation show that plume fingers develop below the flooded land surface. Natural remediation by seaward flowing freshwater is relatively slow, such that reducing the salt concentration in the aquifer down to drinking water standards takes up to 10 years. Copyright © 2013 Elsevier B.V. All rights reserved.

Improving short-range ensemble Kalman storm surge forecasting using robust adaptive inflation

NARCIS (Netherlands)

Altaf, M.U.; Butler, T.; Luo, X.; Dawson, C.; Mayo, T.; Hoteit, I.

2013-01-01

This paper presents a robust ensemble filtering methodology for storm surge forecasting based on the singular evolutive interpolated Kalman (SEIK) filter, which has been implemented in the framework of the H? filter. By design, an H? filter is more robust than the common Kalman filter in the sense

Tropical Cyclone Storm Surge Inundation and Velocity Hazard Mapping of the State of Andhra Pradesh (India) using ADCIRC

Science.gov (United States)

Brackins, J. T.; Kalyanapu, A. J.

2017-12-01

The Northern Indian Ocean Bay of Bengal region, including parts of India, Bangladesh, Myanmar, and Sri Lanka, is the largest bay in the world and is structured in such a manner as to produce the world's largest tropical cyclone (TC) storm surges (SS), with approximately five surge events greater than 5 meters in magnitude each decade. (Needham et al. 2015). Although some studies have been performed to attempt to capture the magnitude and location of historical surges (Shaji et al. 2014) and to model surges in the immediate sense, there is a notable lack of application to the effects on coastal infrastructure in these areas. Given that these areas are some of the most densely populated and least economically able to prepare and recover, it is important to consider the potential effects of storm surge to discover areas where improvements can be made with the limited resources available to these areas. To this end, an ADvanced-CIRCulation (ADCIRC) model (Luettich and Westerink 2004) was created for the Bay of Bengal, using the General Bathymetric Chart of the Oceans (GEBCO 2014) as bathymetric and topographic data, and a combination of the Joint Typhoon Warning Center (JTWC) and India Meteorological Department (IMD) records for storm tracks. For the state of Andhra Pradesh, several major TC events ranging from 1977 to 2014 were selected to be modeled with the goal of creating hazard maps of storm surge inundation and velocity for the state. These hazard maps would be used to identify high-vulnerability areas with the goal of implementing land-use planning and coastal development practices that will aid in ameliorating both the loss of life and economic damages sustained as a result of these TCs.

An ensemble study of extreme storm surge related water levels in the North Sea in a changing climate

Directory of Open Access Journals (Sweden)

A. Sterl

2009-09-01

Full Text Available The height of storm surges is extremely important for a low-lying country like The Netherlands. By law, part of the coastal defence system has to withstand a water level that on average occurs only once every 10 000 years. The question then arises whether and how climate change affects the heights of extreme storm surges. Published research points to only small changes. However, due to the limited amount of data available results are usually limited to relatively frequent extremes like the annual 99%-ile. We here report on results from a 17-member ensemble of North Sea water levels spaning the period 1950–2100. It was created by forcing a surge model of the North Sea with meteorological output from a state-of-the-art global climate model which has been driven by greenhouse gas emissions following the SRES A1b scenario. The large ensemble size enables us to calculate 10 000 year return water levels with a low statistical uncertainty. In the one model used in this study, we find no statistically significant change in the 10 000 year return values of surge heights along the Dutch during the 21st century. Also a higher sea level resulting from global warming does not impact the height of the storm surges. As a side effect of our simulations we also obtain results on the interplay between surge and tide.

Great Britain Storm Surge Modeling for a 10,000-Year Stochastic Catalog with the Effect of Sea Level Rise

Science.gov (United States)

Keshtpoor, M.; Carnacina, I.; Blair, A.; Yablonsky, R. M.

2017-12-01

Storm surge caused by Extratropical Cyclones (ETCs) has significantly impacted not only the life of private citizens but also the insurance and reinsurance industry in Great Britain. The storm surge risk assessment requires a larger dataset of storms than the limited recorded historical ETCs. Thus, historical ETCs were perturbed to generate a 10,000-year stochastic catalog that accounts for surge-generating ETCs in the study area with return periods from one year to 10,000 years. Delft3D-Flexible Mesh hydrodynamic model was used to numerically simulate the storm surge along the Great Britain coastline. A nested grid technique was used to increase the simulation grid resolution up to 200 m near the highly populated coastal areas. Coarse and fine mesh models were calibrated and validated using historical recorded water elevations. Then, numerical simulations were performed on a 10,000-year stochastic catalog. The 50-, 100-, and 500-year return period maps were generated for Great Britain coastal areas. The corresponding events with return periods of 50-, 100-, and 500-years in Humber Bay and Thames River coastal areas were identified, and simulated with the consideration of projected sea level rises to reveal the effect of rising sea levels on the inundation return period maps in two highly-populated coastal areas. Finally, the return period of Storm Xaver (2013) was determined with and without the effect of rising sea levels.

Maximum wind radius estimated by the 50 kt radius: improvement of storm surge forecasting over the western North Pacific

Science.gov (United States)

Takagi, Hiroshi; Wu, Wenjie

2016-03-01

Even though the maximum wind radius (Rmax) is an important parameter in determining the intensity and size of tropical cyclones, it has been overlooked in previous storm surge studies. This study reviews the existing estimation methods for Rmax based on central pressure or maximum wind speed. These over- or underestimate Rmax because of substantial variations in the data, although an average radius can be estimated with moderate accuracy. As an alternative, we propose an Rmax estimation method based on the radius of the 50 kt wind (R50). Data obtained by a meteorological station network in the Japanese archipelago during the passage of strong typhoons, together with the JMA typhoon best track data for 1990-2013, enabled us to derive the following simple equation, Rmax = 0.23 R50. Application to a recent strong typhoon, the 2015 Typhoon Goni, confirms that the equation provides a good estimation of Rmax, particularly when the central pressure became considerably low. Although this new method substantially improves the estimation of Rmax compared to the existing models, estimation errors are unavoidable because of fundamental uncertainties regarding the typhoon's structure or insufficient number of available typhoon data. In fact, a numerical simulation for the 2013 Typhoon Haiyan as well as 2015 Typhoon Goni demonstrates a substantial difference in the storm surge height for different Rmax. Therefore, the variability of Rmax should be taken into account in storm surge simulations (e.g., Rmax = 0.15 R50-0.35 R50), independently of the model used, to minimize the risk of over- or underestimating storm surges. The proposed method is expected to increase the predictability of major storm surges and to contribute to disaster risk management, particularly in the western North Pacific, including countries such as Japan, China, Taiwan, the Philippines, and Vietnam.

Erosion and its rate on an accumulative Polish dune coast: the effects of the January 2012 storm surge

OpenAIRE

Łabuz, Tomasz A.

2014-01-01

The Polish coast is a non-tidal area; its shores are affected mainly by autumn-winter storm surges. Those of 6 and 14 January 2012 are representative of the forces driving the erosion of normally accumulative sections of coastal dunes, monitored by the author since 1997. The sea level maximum during these two storm surges reached 1.2 to 1.5 m amsl along the Polish coast. Land forms up to 3 m amsl were inundated. Beaches and low parts of the coast up to this height were rebuilt by sea waves at...

New technology and tool prepared for communication against storm surges.

Science.gov (United States)

Letkiewicz, Beata

2010-05-01

The aim of the presentation is description of the new technology and tool prepared for communication, information and issue of warnings against storm surges. The Maritime Branch of the Institute of Meteorology and Water Management is responsible for preparing the forecast as warning, where the end users are Government Officials and Public. The Maritime Branch carry out the project "Strengthening the administrative capacity in order to improve the management of Polish coastal zone environment" (supported by a grant from Norway through the Norwegian Financial Mechanism). The expected final result of the project is web site www.baltyk.pogodynka.pl. One of the activities of the project is - set up of information website www.baltyk.pogodynka.pl, giving public access to the complied data. Information on web site: - meta data - marine data (on-line measurement: sea level, water temperature, salinity, oxygen concentration); - data bases of mathematical model outputs - forecast data (sea level, currents); - ice conditions of the Baltic Sea, - instructions, information materials with information of polish coastal zone. The aim of set up of the portal is development of communication between users of the system, exchange of the knowledge of marine environment and natural hazards such as storm surges, improving the ability of the region in the scope of the data management about the sea environment and the coastal zone.

Potential Hydrodynamic Loads on Coastal Bridges in the Greater New York Area due to Extreme Storm Surge and Wave

Science.gov (United States)

2018-04-18

This project makes a computer modeling study on vulnerability of coastal bridges in New York City (NYC) metropolitan region to storm surges and waves. Prediction is made for potential surges and waves in the region and consequent hydrodynamic load an...

Coastal Flooding Hazards due to storm surges and subsidence

DEFF Research Database (Denmark)

Sørensen, Carlo; Knudsen, Per; Andersen, Ole B.

Flooding hazard and risk mapping are major topics in low-lying coastal areas before even considering the adverse effects of sea level rise (SLR) due to climate change. While permanent inundation may be a prevalent issue, more often floods related to extreme events (storm surges) have the largest...... damage potential.Challenges are amplified in some areas due to subsidence from natural and/or anthropogenic causes. Subsidence of even a few mm/y may over time greatly impair the safety against flooding of coastal communities and must be accounted for in order to accomplish the economically most viable...

Hurricane Matthew (2016) and its Storm Surge Inundation under Global Warming Scenarios: Application of an Interactively Coupled Atmosphere-Ocean Model

Science.gov (United States)

Jisan, M. A.; Bao, S.; Pietrafesa, L.; Pullen, J.

2017-12-01

An interactively coupled atmosphere-ocean model was used to investigate the impacts of future ocean warming, both at the surface and the layers below, on the track and intensity of a hurricane and its associated storm surge and inundation. The category-5 hurricane Matthew (2016), which made landfall on the South Carolina coast of the United States, was used for the case study. Future ocean temperature changes and sea level rise (SLR) were estimated based on the projection of Inter-Governmental Panel on Climate Change (IPCC)'s Representative Concentration Pathway scenarios RCP 2.6 and RCP 8.5. After being validated with the present-day observational data, the model was applied to simulate the changes in track, intensity, storm surge and inundation that Hurricane Matthew would cause under future climate change scenarios. It was found that a significant increase in hurricane intensity, storm surge water level, and inundation area for Hurricane Matthew under future ocean warming and SLR scenarios. For example, under the RCP 8.5 scenario, the maximum wind speed would increase by 17 knots (14.2%), the minimum sea level pressure would decrease by 26 hPa (2.85%), and the inundated area would increase by 401 km2 (123%). By including the effect of SLR for the middle-21st-century scenario, the inundated area will further increase by up to 49.6%. The increase in the hurricane intensity and the inundated area was also found for the RCP 2.6 scenario. The response of sea surface temperature was analyzed to investigate the change in intensity. A comparison was made between the impacts when only the sea surface warming is considered versus when both the sea surface and the underneath layers are considered. These results showed that even without the effect of SLR, the storm surge level and the inundated area would be higher due to the increased hurricane intensity under the influence of the future warmer ocean temperature. The coupled effect of ocean warming and SLR would cause the

Numerical Modeling of Coastal Inundation and Sedimentation by Storm Surge, Tides, and Waves at Norfolk, Virginia, USA

Science.gov (United States)

2012-07-01

hurricanes (tropical) with a 50-year and a 100-year return period, and one winter storm ( extratropical ) occurred in October 1982. There are a total of 15...under the 0-m and 2-m SLR scenarios, respectively. • Tropical and extratropical storms induce extensive coastal inundation around the military...1 NUMERICAL MODELING OF COASTAL INUNDATION AND SEDIMENTATION BY STORM SURGE, TIDES, AND WAVES AT NORFOLK, VIRGINIA, USA Honghai Li 1 , Lihwa Lin 1

Challenges in Downscaling Surge and Flooding Predictions Associated with Major Coastal Storm Events

Science.gov (United States)

Bowman, M. J.

2015-12-01

Coastal zone managers, elected officials and emergency planning personnel are continually seeking more reliable estimates of storm surge and inundation for better land use planning, the design, construction and operation of coastal defense systems, resilience evaluation and evacuation planning. Customers of modern regional weather and storm surge prediction models demand high resolution, speed, accuracy, with informative, interactive graphics and easy evaluation of potentially dangerous threats to life and property. These challenges continue to get more difficult as the demand for street-scale and even building-scale predictions increase. Fluctuations in sub-grid-scale wind and water velocities can lead to unsuspected, unanticipated and dangerous flooding in local communities. But how reliable and believable are these models given the inherent natural uncertainty and chaotic behavior in the underlying dynamics, which can lead to rapid and unexpected perturbations in the wind and pressure fields and hence coastal flooding? Traditionally this uncertainty has been quantified by the use of the ensemble method, where a suite of model runs are made with varying physics and initial conditions, presenting the mean and variance of the ensemble as the best metrics possible. But this assumes that each component is equally possible and is statistically independent of the others. But this is rarely true, although the "safety in numbers" approach is comforting to those faced with life and death decisions. An example of the ensemble method is presented for the trajectory of superstorm Sandy's storm center as it approached coastal New Jersey. If one were to ask the question "was Sandy a worst case scenario", the answer would be "no: small variations in the timing (vis-à-vis tide phase) and location of landfall could easily have led to an additional surge of +50 cm at The Battery NY with even more catastrophic consequences to those experienced".

Ensemble projection of the sea level rise impact on storm surge and inundation at the coast of Bangladesh

Science.gov (United States)

Jisan, Mansur Ali; Bao, Shaowu; Pietrafesa, Leonard J.

2018-01-01

The hydrodynamic model Delft3D is used to study the impact of sea level rise (SLR) on storm surge and inundation in the coastal region of Bangladesh. To study the present-day inundation scenario, the tracks of two known tropical cyclones (TC) were used: Aila (Category 1; 2009) and Sidr (Category 5; 2007). Model results were validated with the available observations. Future inundation scenarios were generated by using the strength of TC Sidr, TC Aila and an ensemble of historical TC tracks but incorporating the effect of SLR. Since future change in storm surge inundation under SLR impact is a probabilistic incident, a probable range of future change in the inundated area was calculated by taking into consideration the uncertainties associated with TC tracks, intensities and landfall timing. The model outputs showed that the inundated area for TC Sidr, which was calculated as 1860 km2, would become 31 % larger than the present-day scenario if a SLR of 0.26 m occurred during the mid-21st-century climate scenario. Similarly to that, an increasing trend was found for the end-21st-century climate scenario. It was found that with a SLR of 0.54 m, the inundated area would become 53 % larger than the present-day case. Along with the inundation area, the impact of SLR was examined for changes in future storm surge level. A significant increase of 14 % was found in storm surge level for the case of TC Sidr at Barisal station if a SLR of 0.26 m occurred in the mid-21st century. Similarly to that, an increase of 29 % was found at storm surge level with a SLR of 0.54 m in this location for the end-21st-century climate scenario. Ensemble projections based on uncertainties of future TC events also showed that, for a change of 0.54 m in SLR, the inundated area would range between 3500 and 3750 km2, whereas for present-day SLR simulations it was found within the range of 1000-1250 km2. These results revealed that even if the future TCs remain at the same strength as at present, the

Monitoring duration and extent of storm-surge and flooding in Western Coastal Louisiana marshes with Envisat ASAR data

Science.gov (United States)

Ramsey, E.; Lu, Z.; Suzuoki, Y.; Rangoonwala, A.; Werle, D.

2011-01-01

Inundation maps of coastal marshes in western Louisiana were created with multitemporal Envisat Advanced Synthetic Aperture (ASAR) scenes collected before and during the three months after Hurricane Rita landfall in September 2005. Corroborated by inland water-levels, 7 days after landfall, 48% of coastal estuarine and palustrine marshes remained inundated by storm-surge waters. Forty-five days after landfall, storm-surge inundated 20% of those marshes. The end of the storm-surge flooding was marked by an abrupt decrease in water levels following the passage of a storm front and persistent offshore winds. A complementary dramatic decrease in flood extent was confirmed by an ASAR-derived inundation map. In nonimpounded marshes at elevations ;80 cm during the first month after Rita landfall. After this initial period, drainage from marshes-especially impounded marshes-was hastened by the onset of offshore winds. Following the abrupt drops in inland water levels and flood extent, rainfall events coinciding with increased water levels were recorded as inundation re-expansion. This postsurge flooding decreased until only isolated impounded and palustrine marshes remained inundated. Changing flood extents were correlated to inland water levels and largely occurred within the same marsh regions. Trends related to incremental threshold increases used in the ASAR change-detection analyses seemed related to the preceding hydraulic and hydrologic events, and VV and HH threshold differences supported their relationship to the overall wetland hydraulic condition.

Assessing inundation hazards to nuclear powerplant sites using geologically extended histories of riverine floods, tsunamis, and storm surges

Science.gov (United States)

O'Connor, Jim; Atwater, Brian F.; Cohn, Timothy A.; Cronin, Thomas M.; Keith, Mackenzie K.; Smith, Christopher G.; Mason, Jr., Robert R.

2014-01-01

Most nuclear powerplants in the United States are near rivers, large lakes, or oceans. As evident from the Fukushima Daiichi, Japan, disaster of 2011, these water bodies pose inundation threats. Geologic records can extend knowledge of rare hazards from flooding, storm surges, and tsunamis. This knowledge can aid in assessing the safety of critical structures such as dams and energy plants, for which even remotely possible hazards are pertinent. Quantitative analysis of inundation from geologic records perhaps is most developed for and applied to riverine flood hazards, but because of recent natural disasters, geologic investigations also are now used widely for understanding tsunami hazards and coastal storm surges.

Compound simulation of fluvial floods and storm surges in a global coupled river-coast flood model: Model development and its application to 2007 Cyclone Sidr in Bangladesh

Science.gov (United States)

Ikeuchi, Hiroaki; Hirabayashi, Yukiko; Yamazaki, Dai; Muis, Sanne; Ward, Philip J.; Winsemius, Hessel C.; Verlaan, Martin; Kanae, Shinjiro

2017-08-01

Water-related disasters, such as fluvial floods and cyclonic storm surges, are a major concern in the world's mega-delta regions. Furthermore, the simultaneous occurrence of extreme discharges from rivers and storm surges could exacerbate flood risk, compared to when they occur separately. Hence, it is of great importance to assess the compound risks of fluvial and coastal floods at a large scale, including mega-deltas. However, most studies on compound fluvial and coastal flooding have been limited to relatively small scales, and global-scale or large-scale studies have not yet addressed both of them. The objectives of this study are twofold: to develop a global coupled river-coast flood model; and to conduct a simulation of compound fluvial flooding and storm surges in Asian mega-delta regions. A state-of-the-art global river routing model was modified to represent the influence of dynamic sea surface levels on river discharges and water levels. We conducted the experiments by coupling a river model with a global tide and surge reanalysis data set. Results show that water levels in deltas and estuaries are greatly affected by the interaction between river discharge, ocean tides and storm surges. The effects of storm surges on fluvial flooding are further examined from a regional perspective, focusing on the case of Cyclone Sidr in the Ganges-Brahmaputra-Meghna Delta in 2007. Modeled results demonstrate that a >3 m storm surge propagated more than 200 km inland along rivers. We show that the performance of global river routing models can be improved by including sea level dynamics.

The transforming perception of a regional geohazard between coastal defence and mediated discourse on global warming: Storm surges in Hamburg, Germany

Science.gov (United States)

Neverla, I.; Lüthje, C.

2010-03-01

The term regional geohazard is used for a major geophysical risk which can lead to a natural disaster. The effects will be strictly located to a specific region. It is expected but still not proven that global warming will intensify weather extremes and thus the number of regional geohazards will increase. Regional geohazards are not dangerous per se, but from the perspective of human being certain weather and nature extremes are considered dangerous as they impose damage on human beings and their belongings. Therefore the media often call them ‘natural disaster’ and as a matter of fact it seems to be a ‘must’ - according to theory and practice of news selections - that media report on any natural disaster that occur in their region. Moreover, media even report on geohazards in any other region as soon as these events seem to have any general impact. The major geophysical risk along the coast of the North Sea is storm surges. A long list of historical disasters has deeply engraved the ubiquity of this hazard into the collective memory and habitus of the local population. Not only coastal region is concerned by this danger but also the megacity of Hamburg. Hamburg is the second-largest city in Germany and the sixth-largest city in the European Union. The Hamburg Metropolitan Region has more than 4.3 million inhabitants. The estuary of the river Elbe extends from Cuxhaven (coast) to Hamburg a distance of about 130 km. Hamburg has often been subject to storm surges with significant damages. But after the storm flood in 1855 for more than 100 years until 1962 no severe storm surge happened. The Big Flood in the night from February 16 to February 17 1962 destroyed the homes of about 60.000 people. The death toll amounted to 315 in the city of Hamburg, where the storm surge had a traumatic impact and was followed by political decisions driven by the believe in technological solutions. After 1962 massive investments into the coastal defence were made and dikes

Regional Risk Assessment for the analysis of the risks related to storm surge extreme events in the coastal area of the North Adriatic Sea.

Science.gov (United States)

Rizzi, Jonathan; Torresan, Silvia; Gallina, Valentina; Critto, Andrea; Marcomini, Antonio

2013-04-01

Europe's coast faces a variety of climate change threats from extreme high tides, storm surges and rising sea levels. In particular, it is very likely that mean sea level rise will contribute to upward trends in extreme coastal high water levels, thus posing higher risks to coastal locations currently experiencing coastal erosion and inundation processes. In 2007 the European Commission approved the Flood Directive (2007/60/EC), which has the main purpose to establish a framework for the assessment and management of flood risks for inland and coastal areas, thus reducing the adverse consequences for human health, the environment, cultural heritage and economic activities. Improvements in scientific understanding are thus needed to inform decision-making about the best strategies for mitigating and managing storm surge risks in coastal areas. The CLIMDAT project is aimed at improving the understanding of the risks related to extreme storm surge events in the coastal area of the North Adriatic Sea (Italy), considering potential climate change scenarios. The project implements a Regional Risk Assessment (RRA) methodology developed in the FP7 KULTURisk project for the assessment of physical/environmental impacts posed by flood hazards and employs the DEcision support SYstem for Coastal climate change impact assessment (DESYCO) for the application of the methodology to the case study area. The proposed RRA methodology is aimed at the identification and prioritization of targets and areas at risk from water-related natural hazards in the considered region at the meso-scale. To this aim, it integrates information about extreme storm surges with bio-geophysical and socio-economic information (e.g. vegetation cover, slope, soil type, population density) of the analyzed receptors (i.e. people, economic activities, cultural heritages, natural and semi-natural systems). Extreme storm surge hazard scenarios are defined using tide gauge time series coming from 28 tide gauge

Modeling the Effects of Storm Surge from Hurricane Jeanne on Saltwater Intrusion into the Surficial Aquifer, East-Central Florida (USA)

Science.gov (United States)

Xiao, H.; Wang, D.; Hagen, S. C.; Medeiros, S. C.; Hall, C. R.

2017-12-01

Saltwater intrusion (SWI) that has been widely recognized as a detrimental issue causing the deterioration of coastal aquifer water quality and degradation of coastal ecosystems. While it is widely recognized that SWI is exacerbated worldwide due to global sea-level rise, we show that increased SWI from tropical cyclones under climate change is also a concern. In the Cape Canaveral Barrier Island Complex (CCBIC) located in east-central Florida, the salinity level of the surficial aquifer is of great importance to maintain a bio-diverse ecosystem and to support the survival of various vegetation species. Climate change induced SWI into the surficial aquifer can lead to reduction of freshwater storage and alteration of the distribution and productivity of vegetation communities. In this study, a three-dimensional variable-density SEAWAT model is developed and calibrated to investigate the spatial and temporal variation of salinity level in the surficial aquifer of CCBIC. We link the SEAWAT model to surge model data to examine the effects of storm surge from Hurricane Jeanne. Simulation results indicate that the surficial aquifer salinity level increases significantly right after the occurrence of storm surge because of high aquifer permeability and rapid infiltration and diffusion of the overtopping saltwater, while the surficial aquifer salinity level begins to decrease after the fresh groundwater recharge from the storm's rainfall. The tropical storm precipitation generates an effective hydraulic barrier further impeding SWI and providing seaward freshwater discharge for saltwater dilution and flushing. To counteract the catastrophic effects of storm surge, this natural remediation process may take at least 15-20 years or even several decades. These simulation results contribute to ongoing research focusing on forecasting regional vegetation community responses to climate change, and are expected to provide a useful reference for climate change adaptation planning

Compound simulation of fluvial floods and storm surges in a global coupled river-coast flood model : Model development and its application to 2007 Cyclone Sidr in Bangladesh

NARCIS (Netherlands)

Ikeuchi, Hiroaki; Hirabayashi, Yukiko; Yamazaki, Dai; Muis, Sanne; Ward, Philip J.; Winsemius, Hessel C.; Verlaan, Martin; Kanae, Shinjiro

2017-01-01

Water-related disasters, such as fluvial floods and cyclonic storm surges, are a major concern in the world's mega-delta regions. Furthermore, the simultaneous occurrence of extreme discharges from rivers and storm surges could exacerbate flood risk, compared to when they occur separately. Hence, it

Visualizing uncertainties in a storm surge ensemble data assimilation and forecasting system

KAUST Repository

Hollt, Thomas

2015-01-15

We present a novel integrated visualization system that enables the interactive visual analysis of ensemble simulations and estimates of the sea surface height and other model variables that are used for storm surge prediction. Coastal inundation, caused by hurricanes and tropical storms, poses large risks for today\\'s societies. High-fidelity numerical models of water levels driven by hurricane-force winds are required to predict these events, posing a challenging computational problem, and even though computational models continue to improve, uncertainties in storm surge forecasts are inevitable. Today, this uncertainty is often exposed to the user by running the simulation many times with different parameters or inputs following a Monte-Carlo framework in which uncertainties are represented as stochastic quantities. This results in multidimensional, multivariate and multivalued data, so-called ensemble data. While the resulting datasets are very comprehensive, they are also huge in size and thus hard to visualize and interpret. In this paper, we tackle this problem by means of an interactive and integrated visual analysis system. By harnessing the power of modern graphics processing units for visualization as well as computation, our system allows the user to browse through the simulation ensembles in real time, view specific parameter settings or simulation models and move between different spatial and temporal regions without delay. In addition, our system provides advanced visualizations to highlight the uncertainty or show the complete distribution of the simulations at user-defined positions over the complete time series of the prediction. We highlight the benefits of our system by presenting its application in a real-world scenario using a simulation of Hurricane Ike.

Impact of performance interdependencies on structural vulnerability: A systems perspective of storm surge risk to coastal residential communities

International Nuclear Information System (INIS)

Hatzikyriakou, Adam; Lin, Ning

2017-01-01

Interaction between residential structures during natural hazards can lead to interdependencies in their performance. During storm surge, for example, structures can affect the performance of inland buildings by generating damaging waterborne debris or by beneficially dampening surge loads. Quantifying the impact of this interaction on structural vulnerability is critical for risk assessment and informed decision-making. In this study we present and implement two general modeling approaches for investigating such interdependencies. The first method is to condition the vulnerability of a structure on the performance of neighboring buildings using a Markov model. The second uses a marginal model to account for correlation between damage observations when estimating a structure's vulnerability to the hazard. Both approaches are implemented using a case study of an impacted coastal community during Hurricane Sandy (2012). Findings indicate that a structure's performance during storm surge is strongly dependent on the damage state of the structure immediately seaward. Furthermore, considering the correlated damage states of buildings increases statistical uncertainty when relating structural performance to hazard intensity. Motivated by these findings, we propose a more coordinated approach to coastal risk mitigation which considers the effects of interdependencies on insurance pricing, structural design, mitigation strategies and community resilience. - Highlights: • Interaction between residential structures leads to performance interdependencies. • Interdependencies during storm surge are due to debris and structural shielding. • Markov model treats interdependencies as an additional demand parameter. • Marginal model incorporates damage correlation into regression estimation. • System behavior should be considered in community risk and resilience.

A tale of two storms: Surges and sediment deposition from Hurricanes Andrew and Wilma in Florida’s southwest coast mangrove forests: Chapter 6G in Science and the storms-the USGS response to the hurricanes of 2005

Science.gov (United States)

Smith, Thomas J.; Anderson, Gordon H.; Tiling, Ginger

2007-01-01

Hurricanes can be very different from each other. Here we examine the impacts that two hurricanes, Andrew and Wilma, had in terms of storm surge and sediment deposition on the southwest coast of Florida. Although Wilma was the weaker storm, it had the greater impact. Wilma had the higher storm surge over a larger area and deposited more sediment than did Andrew. This effect was most likely due to the size of Wilma's eye, which was four times larger than that of Andrew.

Assessing economic impact of storm surge under projected sea level rise scenarios

Science.gov (United States)

Del Angel, D. C.; Yoskowitz, D.

2017-12-01

Global sea level is expected to rise 0.2-2m by the year 2100. Rising sea level is expected to have a number of impacts such as erosion, saltwater intrusion, and decline in coastal wetlands; all which have direct and indirect socio-economic impact to coastal communities. By 2050, 25% of the world's population will reside within flood-prone areas. These statistics raise a concern for the economic cost that sea level and flooding has on the growing coastal communities. Economic cost of storm surge inundation and rising seas may include loss or damage to public facilities and infrastructure that may become temporarily inaccessible, as well as disruptions to business and services. This goal of this project is to assess economic impacts of storms under four SLR scenarios including low, intermediate-low, intermediate-high, and high (0.2m, 0.5m, 1.2m and 2m, respectively) in the Northern Gulf of Mexico region. To assess flooding impact on communities from storm surge, this project utilizes HAZUS-MH software - a Geographic Information System (GIS)-based modeling tool developed by the Federal Emergency Management Agency - to estimate physical, economic, and social impacts of natural disasters such as floods, earthquakes and hurricanes. The HAZUS database comes integrated with aggregate and site specific inventory which includes: demographic data, general building stock, agricultural statistics, vehicle inventory, essential facilities, transportation systems, utility systems (among other sensitive facilities). User-defined inundation scenarios will serve to identify assets at risk and damage estimates will be generated using the Depth Damage Function included in the HAZUS software. Results will focus on 3 communities in the Gulf and highlight changes in storm flood impact. This approach not only provides a method for economic impact assessment but also begins to create a link between ecosystem services and natural and nature-based features such as wetlands, beaches and dunes

The Surge, Wave, and Tide Hydrodynamics (SWaTH) network of the U.S. Geological Survey—Past and future implementation of storm-response monitoring, data collection, and data delivery

Science.gov (United States)

Verdi, Richard J.; Lotspeich, R. Russell; Robbins, Jeanne C.; Busciolano, Ronald J.; Mullaney, John R.; Massey, Andrew J.; Banks, William S.; Roland, Mark A.; Jenter, Harry L.; Peppler, Marie C.; Suro, Thomas P.; Schubert, Christopher E.; Nardi, Mark R.

2017-06-20

After Hurricane Sandy made landfall along the northeastern Atlantic coast of the United States on October 29, 2012, the U.S. Geological Survey (USGS) carried out scientific investigations to assist with protecting coastal communities and resources from future flooding. The work included development and implementation of the Surge, Wave, and Tide Hydrodynamics (SWaTH) network consisting of more than 900 monitoring stations. The SWaTH network was designed to greatly improve the collection and timely dissemination of information related to storm surge and coastal flooding. The network provides a significant enhancement to USGS data-collection capabilities in the region impacted by Hurricane Sandy and represents a new strategy for observing and monitoring coastal storms, which should result in improved understanding, prediction, and warning of storm-surge impacts and lead to more resilient coastal communities.As innovative as it is, SWaTH evolved from previous USGS efforts to collect storm-surge data needed by others to improve storm-surge modeling, warning, and mitigation. This report discusses the development and implementation of the SWaTH network, and some of the regional stories associated with the landfall of Hurricane Sandy, as well as some previous events that informed the SWaTH development effort. Additional discussions on the mechanics of inundation and how the USGS is working with partners to help protect coastal communities from future storm impacts are also included.

PCR and culture identification of pathogenic Leptospira spp. from coastal soil in Leyte, Philippines, after a storm surge during Super Typhoon Haiyan (Yolanda).

Science.gov (United States)

Saito, Mitsumasa; Miyahara, Satoshi; Villanueva, Sharon Y A M; Aramaki, Natsumi; Ikejiri, Mami; Kobayashi, Yoshie; Guevarra, Jonathan P; Masuzawa, Toshiyuki; Gloriani, Nina G; Yanagihara, Yasutake; Yoshida, Shin-ichi

2014-11-01

Leptospirosis is a zoonosis caused by pathogenic Leptospira spp. Most of the outbreaks of leptospirosis occur after floods caused by heavy rain in countries where Leptospira spp. are endemic. It has been believed that the overflow of seawater rarely causes outbreaks of leptospirosis because the leptospires are killed by salt water. On 8 November 2013, a storm surge caused by Super Typhoon Haiyan (Yolanda) inundated the entire coastal areas of Tacloban and Palo in Leyte, Philippines. The present study was carried out in order to determine whether the environmental leptospires in soil were able to survive after the storm surge in the affected areas. We collected 23 wet soil samples along the coastal areas of Tacloban and Palo 2 months after the storm surge. The samples were suspended in HEPES buffer, and the supernatants were cultured in liquid or semisolid Korthof's medium supplemented with five antimicrobial agents to inhibit the growth of contaminants. Leptospires were isolated from primary cultures of 22 out of 23 samples. The DNA of pathogenic Leptospira species was detected in 11 samples (47.8%) by analysis of flaB by nested PCR. Eventually, two pathogenic Leptospira strains were isolated and showed the highest 16S rRNA gene sequence similarity to Leptospira kmetyi. When these isolates were experimentally mixed with soil, they were found to survive in seawater for 4 days. These results show the possibility that leptospires living in soil survived after the storm surge. Our findings may serve as a warning that when seawater inundates the land during a storm surge or a tsunami, an outbreak of leptospirosis could occur in the disaster-stricken area. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Numerical Analysis of Storm Surge and Seiche at Tokyo Bay caused by the 2 Similar Typhoons, Typhoon Phanphon and Vongfong in 2014

Science.gov (United States)

Iwamoto, T.; Takagawa, T.

2017-12-01

A long period damped oscillation, or seiche, sometimes happens inside a harbor after passing typhoon. For some cases, a maximum sea level is observed due to the superposition of astronomical tide and seiche rather than a peak of storm surge. Hence to clarify seiche factors for reducing disaster potential is important, a long-period seiche with a fundamental period of 5.46 hours in Tokyo Bay (Konishi, 2008) was investigated through numerical simulations and analyses. We examined the case of Typhoon Phanphon and Vongfong in 2014 (Hereafter Case P and V). The intensity and moving velocity were similar and the best-tracks were an arc-shaped, typical one approaching to Tokyo Bay. The track of Case V was about 1.5 degree higher latitude than that of Case P, only Typhoon Phanphon caused significant seiche.Firstly, numerical simulations for the 2 storm surges at Tokyo Bay were conducted by Regional Ocean Modeling System (ROMS) and Meso-Scale Model Grid Point Values (MSM-GPV). MSM-GPV gave the 10m wind speed and Sea Level Pressure (SLP), especially the Mean Error (ME) and Root Mean Squire Error (RMSE) of SLP were low compared to the 12 JMA observation points data (Case P: ME -0.303hPa, RMSE 1.87hPa, Case V: ME -0.285hPa, RMSE 0.74hPa). The computational results showed that the maximum of storm surge was underestimated but the difference was less than 20cm at 5 observation points in Tokyo Bay(Fig.1, 2).Then, power spectrals, coherences and phase differences of storm surges at the 5 observation points were obtained by spectral analysis of observed and simulated waveforms. For Case P, the phase-difference between the bay mouth and innermost part of Tokyo Bay was little, and coherence was almost 1(Fig.3, 4). However, for Case V, coherence was small around the fundamental period of 5.46 hours. Furthermore, Empirical Orthogonal Function (EOF) analysis of storm surge, SLP and sea surface stress were conducted. The contributions of EOF1 were above 90% for the all variables, the

Joint projections of sea level and storm surge using a flood index

Science.gov (United States)

Little, C. M.; Lin, N.; Horton, R. M.; Kopp, R. E.; Oppenheimer, M.

2016-02-01

Capturing the joint influence of sea level rise (SLR) and tropical cyclones (TCs) on future coastal flood risk poses significant challenges. To address these difficulties, Little et al. (2015) use a proxy of tropical cyclone activity and a probabilistic flood index that aggregates flood height and duration over a wide area (the US East and Gulf coasts). This technique illuminates the individual impacts of TCs and SLR and their correlation across different coupled climate models. By 2080-2099, changes in the flood index relative to 1986-2005 are substantial and positively skewed: a 10th-90th percentile range of 35-350x higher for a high-end business-as-usual emissions scenario (see figure). This aggregated flood index: 1) is a means to consistently combine TC-driven storm surges and SLR; 2) provides a more robust description of historical surge-climate relationships than is available at any one location; and 3) allows the incorporation of a larger climate model ensemble - which is critical to uncertainty characterization. It does not provide a local view of the complete spectrum of flood severity (i.e. return curves). However, alternate techniques that provide localized return curves (e.g. Lin et al., 2012) are computationally intensive, limiting the set of large-scale climate models that can be incorporated, and require several linked statistical and dynamical models, each with structural uncertainties that are difficult to quantify. Here, we present the results of Little et al. (2015) along with: 1) alternate formulations of the flood index; 2) strategies to localize the flood index; and 3) a comparison of flood index projections to those provided by model-based return curves. We look to this interdisciplinary audience for feedback on the advantages and disadvantages of each tool for coastal planning and decision-making. Lin, N., K. Emanuel, M. Oppenheimer, and E. Vanmarcke, 2012: Physically based assessment of hurricane surge threat under climate change. Nature

Storm Surge Reconstruction and Return Water Level Estimation in Southeast Asia for the 20th Century

NARCIS (Netherlands)

Cid, Alba; Wahl, Thomas; Chambers, Don P.; Muis, Sanne

2018-01-01

We present a methodology to reconstruct the daily maximum storm surge levels, obtained from tide gauges, based on the surrounding atmospheric conditions from an atmospheric reanalysis (20th Century Reanalysis-20CR). Tide gauge records in Southeast Asia are relatively short, so this area is often

Dynamic simulation and numerical analysis of hurricane storm surge under sea level rise with geomorphologic changes along the northern Gulf of Mexico

Science.gov (United States)

Bilskie, Matthew V.; Hagen, S.C.; Alizad, K.A.; Medeiros, S.C.; Passeri, Davina L.; Needham, H.F.; Cox, A.

2016-01-01

This work outlines a dynamic modeling framework to examine the effects of global climate change, and sea level rise (SLR) in particular, on tropical cyclone-driven storm surge inundation. The methodology, applied across the northern Gulf of Mexico, adapts a present day large-domain, high resolution, tide, wind-wave, and hurricane storm surge model to characterize the potential outlook of the coastal landscape under four SLR scenarios for the year 2100. The modifications include shoreline and barrier island morphology, marsh migration, and land use land cover change. Hydrodynamics of 10 historic hurricanes were simulated through each of the five model configurations (present day and four SLR scenarios). Under SLR, the total inundated land area increased by 87% and developed and agricultural lands by 138% and 189%, respectively. Peak surge increased by as much as 1 m above the applied SLR in some areas, and other regions were subject to a reduction in peak surge, with respect to the applied SLR, indicating a nonlinear response. Analysis of time-series water surface elevation suggests the interaction between SLR and storm surge is nonlinear in time; SLR increased the time of inundation and caused an earlier arrival of the peak surge, which cannot be addressed using a static (“bathtub”) modeling framework. This work supports the paradigm shift to using a dynamic modeling framework to examine the effects of global climate change on coastal inundation. The outcomes have broad implications and ultimately support a better holistic understanding of the coastal system and aid restoration and long-term coastal sustainability.

Storm Surge and Wave Impact of Low-Probability Hurricanes on the Lower Delaware Bay—Calibration and Application

Directory of Open Access Journals (Sweden)

Mehrdad Salehi

2018-05-01

Full Text Available Hurricanes pose major threats to coastal communities and sensitive infrastructure, including nuclear power plants, located in the vicinity of hurricane-prone coastal regions. This study focuses on evaluating the storm surge and wave impact of low-probability hurricanes on the lower Delaware Bay using the Delft3D dynamically coupled wave and flow model. The model comprised Overall and Nested domains. The Overall model domain encompassed portions of the Atlantic Ocean, Delaware Bay, and Chesapeake Bay. The two-level Nested model domains encompassed the Delaware Estuary, its floodplain, and a portion of the continental shelf. Low-probability hurricanes are critical considerations in designing and licensing of new nuclear power plants as well as in establishing mitigating strategies for existing power facilities and other infrastructure types. The philosophy behind low-probability hurricane modeling is to establish reasonable water surface elevation and wave characteristics that have very low to no probability of being exceeded in the region. The area of interest (AOI is located on the west bank of Delaware Bay, almost 16 miles upstream of its mouth. The model was first calibrated for Hurricane Isabel (2003 and then applied to synthetic hurricanes with very low probability of occurrence to establish the storm surge envelope at the AOI. The model calibration results agreed reasonably well with field observations of water surface elevation, wind velocity, wave height, and wave period. A range of meteorological, storm track direction, and storm bearing parameters that produce the highest sustained wind speeds were estimated using the National Weather Service (NWS methodology and applied to the model. Simulations resulted in a maximum stillwater elevation and wave height of 7.5 m NAVD88 and 2.5 m, respectively, at the AOI. Comparison of results with the U.S. Army Corps of Engineers, North Atlantic Coastal Comprehensive Study (USACE-NACCS storm surge

Increasing risk of compound flooding from storm surge and rainfall for major US coastal cities

Science.gov (United States)

Wahl, Thomas; Jain, Shaleen; Bender, Jens; Meyers, Steven; Luther, Mark

2016-04-01

Flood risk is a well-known facet of natural hazards along the US coastline where nearly 40% of the population resides in coastal counties. Given the heavy reliance on the coastal zone for natural resources and economic activity, flood preparedness and safety is a key element of long-term resilience. A clear understanding of the various flood types and changes in the frequency of their occurrence is critical towards reliable estimates of vulnerability and potential impacts in the near-term as well as into the future. When the two main flood drivers for coastal areas storm surge and heavy precipitation occur in tandem the potential for significant flooding is much greater than from either in isolation. Exploring the probability of these 'compound events' and understanding the processes driving them is essential to mitigate the associated high impact risks. For the contiguous US the likelihood of the joint occurrence of the two phenomena is largely unknown. Here we show - using storm surge and precipitation records spanning the last century - that the risk of compound flooding is higher for the US east and Gulf coasts, relative to the west coast. We also show that the number of compound events has increased significantly over the last century along large coastline stretches including many of the major coastal cities. For New York City - as an example - this increase is attributed to a shift towards storm surge weather patterns also favouring high precipitation. Preliminary analyses reveal that these synoptic scale changes are closely linked to large scale and low frequency climate variations. Our results demonstrate the importance of assessing the risk of compound flooding within the design process of coastal and urban infrastructure in a non-stationary framework and to explore the potential effects of climate change on these high impact events.

Spatial and temporal analysis of extreme sea level and storm surge events around the coastline of the UK.

Science.gov (United States)

Haigh, Ivan D; Wadey, Matthew P; Wahl, Thomas; Ozsoy, Ozgun; Nicholls, Robert J; Brown, Jennifer M; Horsburgh, Kevin; Gouldby, Ben

2016-12-06

In this paper we analyse the spatial footprint and temporal clustering of extreme sea level and skew surge events around the UK coast over the last 100 years (1915-2014). The vast majority of the extreme sea level events are generated by moderate, rather than extreme skew surges, combined with spring astronomical high tides. We distinguish four broad categories of spatial footprints of events and the distinct storm tracks that generated them. There have been rare events when extreme levels have occurred along two unconnected coastal regions during the same storm. The events that occur in closest succession (sea level events from happening within 4-8 days. Finally, the 2013/14 season was highly unusual in the context of the last 100 years from an extreme sea level perspective.

Influence of Closing Storm Surge Barrier on Extreme Water Levels and Water Exchange; The Limfjord, Denmark

DEFF Research Database (Denmark)

Nørgaard, Jørgen Quvang Harck; Bentzen, Thomas Ruby; Larsen, Torben

2014-01-01

the increased risk of flooding in the estuary has revitalized the discussion whether this connection should be closed. In this paper, it is shown by numerical simulation that the establishment of a storm surge barrier across Thyborøn Channel can significantly reduce the peak water levels in the central...

A geospatial dataset for U.S. hurricane storm surge and sea-level rise vulnerability: Development and case study applications

Directory of Open Access Journals (Sweden)

Megan C. Maloney

2014-01-01

Full Text Available The consequences of future sea-level rise for coastal communities are a priority concern arising from anthropogenic climate change. Here, previously published methods are scaled up in order to undertake a first pass assessment of exposure to hurricane storm surge and sea-level rise for the U.S. Gulf of Mexico and Atlantic coasts. Sea-level rise scenarios ranging from +0.50 to +0.82 m by 2100 increased estimates of the area exposed to inundation by 4–13% and 7–20%, respectively, among different Saffir-Simpson hurricane intensity categories. Potential applications of these hazard layers for vulnerability assessment are demonstrated with two contrasting case studies: potential exposure of current energy infrastructure in the U.S. Southeast and exposure of current and future housing along both the Gulf and Atlantic Coasts. Estimates of the number of Southeast electricity generation facilities potentially exposed to hurricane storm surge ranged from 69 to 291 for category 1 and category 5 storms, respectively. Sea-level rise increased the number of exposed facilities by 6–60%, depending on the sea-level rise scenario and the intensity of the hurricane under consideration. Meanwhile, estimates of the number of housing units currently exposed to hurricane storm surge ranged from 4.1 to 9.4 million for category 1 and category 4 storms, respectively, while exposure for category 5 storms was estimated at 7.1 million due to the absence of landfalling category 5 hurricanes in the New England region. Housing exposure was projected to increase 83–230% by 2100 among different sea-level rise and housing scenarios, with the majority of this increase attributed to future housing development. These case studies highlight the utility of geospatial hazard information for national-scale coastal exposure or vulnerability assessment as well as the importance of future socioeconomic development in the assessment of coastal vulnerability.

Tide-surge interaction in the English Channel

Directory of Open Access Journals (Sweden)

D. Idier

2012-12-01

Full Text Available The English Channel is characterised by strong tidal currents and a wide tidal range, such that their influence on surges is expected to be non-negligible. In order to better assess storm surges in this zone, tide-surge interactions are investigated. A preliminary data analysis on hourly surges indicates some preferential times of occurrence of large storm surges at rising tide, especially in Dunkerque. To examine this further, a numerical modelling approach is chosen, based on the 2DH shallow-water model (MARS. The surges are computed both with and without tide interaction. For the two selected events (the November 2007 North Sea and March 2008 Atlantic storms, it appears that the instantaneous tide-surge interaction is seen to be non-negligible in the eastern half of the English Channel, reaching values of 74 cm (i.e. 50% of the same event maximal storm surge in the Dover Strait for the studied cases. This interaction decreases in westerly direction. In the risk-analysis community in France, extreme water levels have been determined assuming skew surges and tide as independent. The same hydrodynamic model is used to investigate this dependence in the English Channel. Simple computations are performed with the same meteorological forcing, while varying the tidal amplitude, and the skew surge differences D_SS are analysed. Skew surges appear to be tide-dependent, with negligible values of D_SS (<0.05 m over a large portion of the English Channel, although reaching several tens of centimetres in some locations (e.g. the Isle of Wight and Dover Strait.

Beyond Traditional Extreme Value Theory Through a Metastatistical Approach: Lessons Learned from Precipitation, Hurricanes, and Storm Surges

Science.gov (United States)

Marani, M.; Zorzetto, E.; Hosseini, S. R.; Miniussi, A.; Scaioni, M.

2017-12-01

The Generalized Extreme Value (GEV) distribution is widely adopted irrespective of the properties of the stochastic process generating the extreme events. However, GEV presents several limitations, both theoretical (asymptotic validity for a large number of events/year or hypothesis of Poisson occurrences of Generalized Pareto events), and practical (fitting uses just yearly maxima or a few values above a high threshold). Here we describe the Metastatistical Extreme Value Distribution (MEVD, Marani & Ignaccolo, 2015), which relaxes asymptotic or Poisson/GPD assumptions and makes use of all available observations. We then illustrate the flexibility of the MEVD by applying it to daily precipitation, hurricane intensity, and storm surge magnitude. Application to daily rainfall from a global raingauge network shows that MEVD estimates are 50% more accurate than those from GEV when the recurrence interval of interest is much greater than the observational period. This makes MEVD suited for application to satellite rainfall observations ( 20 yrs length). Use of MEVD on TRMM data yields extreme event patterns that are in better agreement with surface observations than corresponding GEV estimates.Applied to the HURDAT2 Atlantic hurricane intensity dataset, MEVD significantly outperforms GEV estimates of extreme hurricanes. Interestingly, the Generalized Pareto distribution used for "ordinary" hurricane intensity points to the existence of a maximum limit wind speed that is significantly smaller than corresponding physically-based estimates. Finally, we applied the MEVD approach to water levels generated by tidal fluctuations and storm surges at a set of coastal sites spanning different storm-surge regimes. MEVD yields accurate estimates of large quantiles and inferences on tail thickness (fat vs. thin) of the underlying distribution of "ordinary" surges. In summary, the MEVD approach presents a number of theoretical and practical advantages, and outperforms traditional

Extreme Wind, Rain, Storm Surge, and Flooding: Why Hurricane Impacts are Difficult to Forecast?

Science.gov (United States)

Chen, S. S.

2017-12-01

The 2017 hurricane season is estimated as one of the costliest in the U.S. history. The damage and devastation caused by Hurricane Harvey in Houston, Irma in Florida, and Maria in Puerto Rico are distinctly different in nature. The complexity of hurricane impacts from extreme wind, rain, storm surge, and flooding presents a major challenge in hurricane forecasting. A detailed comparison of the storm impacts from Harvey, Irma, and Maria will be presented using observations and state-of-the-art new generation coupled atmosphere-wave-ocean hurricane forecast model. The author will also provide an overview on what we can expect in terms of advancement in science and technology that can help improve hurricane impact forecast in the near future.

Nonlinear terms in storm surge predictions: Effect of tide and shelf geometry with case study from Hurricane Rita

Science.gov (United States)

Rego, JoãO. L.; Li, Chunyan

2010-06-01

This study applied the finite volume coastal ocean model (FVCOM) to the storm surge induced by Hurricane Rita along the Louisiana-Texas coast. The model was calibrated for tides and validated with observed water levels. Peak water levels were shown to be lower than expected for a landfall at high tide. For low- and high-tide landfalls, nonlinear effects due to tide-surge coupling were constructive and destructive to total storm tide, respectively, and their magnitude reached up to 70% of the tidal amplitude in the Rita application. Tide-surge interaction was further examined using a standard hurricane under idealized scenarios to evaluate the effects of various shelf geometries, tides, and landfall timings (relative to tide). Nonlinearity was important between landfall position and locations within 2.5 × radius of maximum winds. On an idealized wide continental shelf, nonlinear effects reached up to 80% of the tidal amplitude with an S2 tide and up to 47% with a K1 tide. Increasing average depths by 4 m reduced nonlinear effects to 41% of the tidal amplitude; increasing the slope by a factor of 3 produced nonlinearities of just 26% of tide (both with a K1 tide). The nonlinear effect was greatest for landfalls at low tide, followed by landfalls at high tide and then by landfalls at midebb or midflood.

Monitoring and simulation of salinity changes in response to tide and storm surges in a sandy coastal aquifer system

NARCIS (Netherlands)

Huizer, S.; Karaoulis, M.C.; Oude Essink, G.H.P.; Bierkens, M.F.P.

Tidal dynamics and especially storm surges can have an extensive impact on coastal fresh groundwater resources. Combined with the prospect of sea-level rise and the reliance of many people on these resources, this demonstrates the need to assess the vulnerability of coastal areas to these threats.

Quantifying riverine and storm-surge flood risk by single-family residence: application to Texas.

Science.gov (United States)

Czajkowski, Jeffrey; Kunreuther, Howard; Michel-Kerjan, Erwann

2013-12-01

The development of catastrophe models in recent years allows for assessment of the flood hazard much more effectively than when the federally run National Flood Insurance Program (NFIP) was created in 1968. We propose and then demonstrate a methodological approach to determine pure premiums based on the entire distribution of possible flood events. We apply hazard, exposure, and vulnerability analyses to a sample of 300,000 single-family residences in two counties in Texas (Travis and Galveston) using state-of-the-art flood catastrophe models. Even in zones of similar flood risk classification by FEMA there is substantial variation in exposure between coastal and inland flood risk. For instance, homes in the designated moderate-risk X500/B zones in Galveston are exposed to a flood risk on average 2.5 times greater than residences in X500/B zones in Travis. The results also show very similar average annual loss (corrected for exposure) for a number of residences despite their being in different FEMA flood zones. We also find significant storm-surge exposure outside of the FEMA designated storm-surge risk zones. Taken together these findings highlight the importance of a microanalysis of flood exposure. The process of aggregating risk at a flood zone level-as currently undertaken by FEMA-provides a false sense of uniformity. As our analysis indicates, the technology to delineate the flood risks exists today. © 2013 Society for Risk Analysis.

Application of a Coupled Vegetation Competition and Groundwater Simulation Model to Study Effects of Sea Level Rise and Storm Surges on Coastal Vegetation

Directory of Open Access Journals (Sweden)

Su Yean Teh

2015-09-01

Full Text Available Global climate change poses challenges to areas such as low-lying coastal zones, where sea level rise (SLR and storm-surge overwash events can have long-term effects on vegetation and on soil and groundwater salinities, posing risks of habitat loss critical to native species. An early warning system is urgently needed to predict and prepare for the consequences of these climate-related impacts on both the short-term dynamics of salinity in the soil and groundwater and the long-term effects on vegetation. For this purpose, the U.S. Geological Survey’s spatially explicit model of vegetation community dynamics along coastal salinity gradients (MANHAM is integrated into the USGS groundwater model (SUTRA to create a coupled hydrology–salinity–vegetation model, MANTRA. In MANTRA, the uptake of water by plants is modeled as a fluid mass sink term. Groundwater salinity, water saturation and vegetation biomass determine the water available for plant transpiration. Formulations and assumptions used in the coupled model are presented. MANTRA is calibrated with salinity data and vegetation pattern for a coastal area of Florida Everglades vulnerable to storm surges. A possible regime shift at that site is investigated by simulating the vegetation responses to climate variability and disturbances, including SLR and storm surges based on empirical information.

Influence of a Storm Surge Barrier’s Operation on the Flood Frequency in the Rhine Delta Area

Directory of Open Access Journals (Sweden)

Hua Zhong

2012-05-01

Full Text Available The Rhine River Delta is crucial to the Dutch economy. The Maeslant barrier was built in 1997 to protect the Rhine estuary, with the city and port of Rotterdam, from storm surges. This research takes a simple approach to quantify the influence of the Maeslant storm surge barrier on design water levels behind the barrier. The dikes in the area are supposed to be able to withstand these levels. Equal Level Curves approach is used to calculate the Rotterdam water levels by using Rhine discharges and sea water levels as input. Their joint probability function generates the occurrence frequency of a certain combination that will lead to a certain high water level in Rotterdam. The results show that the flood frequency in Rotterdam is reduced effectively with the controlled barrier in current and in future scenarios influenced by climate change. In addition, an investigation of the sensitivity of the operational parameters suggests that there is a negligible influence on the high water level frequency when the decision closing water level for the barrier is set higher due to the benefits of navigation (but not exceeding the design safety level 4 m MSL.

Erosion reasons and rate on accumulative Polish dune coast caused by the January 2012 storm surge

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Tomasz A. Łabuz

2014-03-01

Full Text Available The Polish coast is a non-tidal area; its shores are affected mainly by autumn-winter storm surges. Those of 6 and 14 January 2012 are representative of the forces driving the erosion of normally accumulative sections of coastal dunes, monitored by the author since 1997. The sea level maximum during these two storm surges reached 1.2 to 1.5 m amsl along the Polish coast. Land forms up to 3 m amsl were inundated. Beaches and low parts of the coast up to this height were rebuilt by sea waves attacking the coast for almost 12 days. Quantitative analyses of the morphological dynamics of the coastal dunes are presented for 57 profiles located along the coast. Only those accumulative sections of the Polish coast are analysed where sand accumulation did occur and led to new foredune development. The mean rate of dune erosion was 2.5 m3 per square metre with an average toe retreat of 1.4 m. Erosion understood as dune retreat was greater when a beach was lower (correlation coefficient 0.8. Dune erosion did not occur on coasts with beaches higher than 3.2 m or on lower ones covered by embryo dunes.

An Approach to Remove the Systematic Bias from the Storm Surge forecasts in the Venice Lagoon

Science.gov (United States)

Canestrelli, A.

2017-12-01

In this work a novel approach is proposed for removing the systematic bias from the storm surge forecast computed by a two-dimensional shallow-water model. The model covers both the Adriatic and Mediterranean seas and provides the forecast at the entrance of the Venice Lagoon. The wind drag coefficient at the water-air interface is treated as a calibration parameter, with a different value for each range of wind velocities and wind directions. This sums up to a total of 16-64 parameters to be calibrated, depending on the chosen resolution. The best set of parameters is determined by means of an optimization procedure, which minimizes the RMS error between measured and modeled water level in Venice for the period 2011-2015. It is shown that a bias is present, for which the peaks of wind velocities provided by the weather forecast are largely underestimated, and that the calibration procedure removes this bias. When the calibrated model is used to reproduce events not included in the calibration dataset, the forecast error is strongly reduced, thus confirming the quality of our procedure. The proposed approach it is not site-specific and could be applied to different situations, such as storm surges caused by intense hurricanes.

Regional-scale impact of storm surges on groundwaters of Texas, Florida and Puerto Rico after 2017 hurricanes Harvey, Irma, Jose, Maria

Science.gov (United States)

Sellier, W. H.; Dürr, H. H.

2017-12-01

Hurricanes and related storm surges have devastating effects on near-shore infrastructure and above-ground installations. They also heavily impact groundwater resources, with potentially millions of people dependant on these resources as a freshwater source. Destructions of casings and direct incursions of saline and/or polluted waters have been widely observed. It is uncertain how extensive the effects are on underground water systems, especially in limestone karst areas such as Florida and Puerto Rico. Here, we report regional-scale water level changes in groundwater systems of Texas, Florida and Puerto Rico for the 2017 Hurricanes Harvey, Irma, Jose and Maria. We collected regional scale data from the USGS Waterdata portal. Puerto Rico shows the strongest increase in groundwater levels in wells during Hurricane Maria, with less reaction for the preceding storms Irma and Jose. Increases in water levels range from 0.5 to 11m, with maximum storm surges in Puerto Rico around 3m. These wells are located throughout Puerto Rico, on the coast and inland. In Florida, most wells that show a response during Hurricane Irma are located in the Miami region. Wells located on the west coast show smaller responses with the exception of one well located directly on Hurricane Irma's track. These wells show an increase of 0.2 to 1.7m. In Texas, wells located in proximity to Hurricane Harvey's track show an increase in water level. The effect of groundwater level increases is not limited to the Texas coast, but inland as well. An increase between 0.03 and 2.9m is seen. Storm surges for both Florida and Texas have ranged from 1.8-3.7m maximum. We discuss the findings in the context of local and regional geology and hydrogeology (presence of connected aquifer systems, faulting, presence of carbonate/karst systems etc.).

Comparative risk assessments for the city of Pointe-à-Pitre (French West Indies): earthquakes and storm surge

Science.gov (United States)

Reveillere, A. R.; Bertil, D. B.; Douglas, J. D.; Grisanti, L. G.; Lecacheux, S. L.; Monfort, D. M.; Modaressi, H. M.; Müller, H. M.; Rohmer, J. R.; Sedan, O. S.

2012-04-01

In France, risk assessments for natural hazards are usually carried out separately and decision makers lack comprehensive information. Moreover, since the cause of the hazard (e.g. meteorological, geological) and the physical phenomenon that causes damage (e.g. inundation, ground shaking) may be fundamentally different, the quantitative comparison of single risk assessments that were not conducted in a compatible framework is not straightforward. Comprehensive comparative risk assessments exist in a few other countries. For instance, the Risk Map Germany project has developed and applied a methodology for quantitatively comparing the risk of relevant natural hazards at various scales (city, state) in Germany. The present on-going work applies a similar methodology to the Pointe-à-Pitre urban area, which represents more than half of the population of Guadeloupe, an overseas region in the French West Indies. Relevant hazards as well as hazard intensity levels differ from continental Europe, which will lead to different conclusions. French West Indies are prone to a large number of hazards, among which hurricanes, volcanic eruptions and earthquakes dominate. Hurricanes cause damage through three phenomena: wind, heavy rainfall and storm surge, the latter having had a preeminent role during the largest historical event in 1928. Seismic risk is characterized by many induced phenomena, among which earthquake shocks dominate. This study proposes a comparison of earthquake and cyclonic storm surge risks. Losses corresponding to hazard intensities having the same probability of occurrence are calculated. They are quantified in a common loss unit, chosen to be the direct economic losses. Intangible or indirect losses are not considered. The methodology therefore relies on (i) a probabilistic hazard assessment, (ii) a loss ratio estimation for the exposed elements and (iii) an economic estimation of these assets. Storm surge hazard assessment is based on the selection of

Storm surges and climate change implications for tidal marshes: Insight from the San Francisco Bay Estuary, California, USA

Science.gov (United States)

Thorne, Karen M.; Buffington, Kevin J.; Swanson, Kathleen; Takekawa, John Y.

2013-01-01

Tidal marshes are dynamic ecosystems, which are influenced by oceanic and freshwater processes and daily changes in sea level. Projected sea-level rise and changes in storm frequency and intensity will affect tidal marshes by altering suspended sediment supply, plant communities, and the inundation duration and depth of the marsh platform. The objective of this research was to evaluate if regional weather conditions resulting in low-pressure storms changed tidal conditions locally within three tidal marshes. We hypothesized that regional storms will increase sea level heights locally, resulting in increased inundation of the tidal marsh platform and plant communities. Using site-level measurements of elevation, plant communities, and water levels, we present results from two storm events in 2010 and 2011 from the San Francisco Bay Estuary (SFBE), California, USA. The January 2010 storm had the lowest recorded sea level pressure in the last 30 years for this region. During the storm episodes, the duration of tidal marsh inundation was 1.8 and 3.1 times greater than average for that time of year, respectively. At peak storm surges, over 65% in 2010 and 93% in 2011 of the plant community was under water. We also discuss the implications of these types of storms and projected sea-level rise on the structure and function of the tidal marshes and how that will impact the hydro-geomorphic processes and marsh biotic communities.

Dynamical Downscaling of Typhoon Vera (1959) and related Storm Surge based on JRA-55 Reanalysis

Science.gov (United States)

Ninomiya, J.; Takemi, T.; Mori, N.; Shibutani, Y.; Kim, S.

2015-12-01

Typhoon Vera in 1959 is historical extreme typhoon that caused severest typhoon damage mainly due to the storm surge up to 389 cm in Japan. Vera developed 895 hPa on offshore and landed with 929.2 hPa. There are many studies of the dynamical downscaling of Vera but it is difficult to simulate accurately because of the lack of the accuracy of global reanalysis data. This study carried out dynamical downscaling experiment of Vera using WRF downscaling forced by JRA-55 that are latest atmospheric model and reanalysis data. In this study, the reproducibility of five global reanalysis data for Typhoon Vera were compered. Comparison shows that reanalysis data doesn't have strong typhoon information except for JRA-55, so that downscaling with conventional reanalysis data goes wrong. The dynamical downscaling method for storm surge is studied very much (e.g. choice of physical model, nudging, 4D-VAR, bogus and so on). In this study, domain size and resolution of the coarse domain were considered. The coarse domain size influences the typhoon route and central pressure, and larger domain restrains the typhoon strength. The results of simulations with different domain size show that the threshold of developing restrain is whether the coarse domain fully includes the area of wind speed more than 15 m/s around the typhoon. The results of simulations with different resolution show that the resolution doesn't affect the typhoon route, and higher resolution gives stronger typhoon simulation.

Strengthening the resiliency of the coastal transportation system through integrated simulation of storm surge, inundation, and non-recurrent congestion in Northeast Florida.

Science.gov (United States)

2013-05-01

In this study, the MTEVA (Developed as part of CMS #2009-010) has been advanced to apply storm surge and evacuation models to the greater Jacksonville area of Northeast Florida. Heuristic and time dynamic algorithms have been enhanced to work with th...

Life defence against big storm surges. Cyclone shelter in Bangladesh; Kyodai takashio kara seimei wo mamoru. Bangladesh no cyclone shelter

Energy Technology Data Exchange (ETDEWEB)

Nakagawa, H. [Kyoto Univ., Kyoto (Japan). Disaster Prevention Research Inst.

1996-08-15

This paper presents the cyclone shelters in Bangladesh. Bangladesh has been damaged by flooding due to big storm surges caused by cyclone every year, losing many human lives and properties. The sea within 100km apart from the coast is gradually shoaling beach shallower than 10m because of sediment transport by the Ganges. Consequently, huge storm surges are easily caused by cyclone generated in Bay of Bengal. The cyclone shelter is only one refuge from cyclone. Construction of the cyclone shelters was opened in the 1960s, and the public work department (PWD) in the government had constructed the cyclone shelters under support by International Development Association (IDA) since 1970. At the same time, BDRCS had constructed the shelters under support by Red Cross Societies of every country, and positive NGOs such as Caritas had been also in the same action. Because many cyclone shelters became too old for use, construction of new cyclone shelters was opened again just after disaster in 1991. 2 refs., 8 figs., 1 tab.

Deep Uncertainties in Sea-Level Rise and Storm Surge Projections: Implications for Coastal Flood Risk Management.

Science.gov (United States)

Oddo, Perry C; Lee, Ben S; Garner, Gregory G; Srikrishnan, Vivek; Reed, Patrick M; Forest, Chris E; Keller, Klaus

2017-09-05

Sea levels are rising in many areas around the world, posing risks to coastal communities and infrastructures. Strategies for managing these flood risks present decision challenges that require a combination of geophysical, economic, and infrastructure models. Previous studies have broken important new ground on the considerable tensions between the costs of upgrading infrastructure and the damages that could result from extreme flood events. However, many risk-based adaptation strategies remain silent on certain potentially important uncertainties, as well as the tradeoffs between competing objectives. Here, we implement and improve on a classic decision-analytical model (Van Dantzig 1956) to: (i) capture tradeoffs across conflicting stakeholder objectives, (ii) demonstrate the consequences of structural uncertainties in the sea-level rise and storm surge models, and (iii) identify the parametric uncertainties that most strongly influence each objective using global sensitivity analysis. We find that the flood adaptation model produces potentially myopic solutions when formulated using traditional mean-centric decision theory. Moving from a single-objective problem formulation to one with multiobjective tradeoffs dramatically expands the decision space, and highlights the need for compromise solutions to address stakeholder preferences. We find deep structural uncertainties that have large effects on the model outcome, with the storm surge parameters accounting for the greatest impacts. Global sensitivity analysis effectively identifies important parameter interactions that local methods overlook, and that could have critical implications for flood adaptation strategies. © 2017 Society for Risk Analysis.

Erosion and its rate on an accumulative Polish dune coast: the effects of the January 2012 storm surge

Directory of Open Access Journals (Sweden)

Tomasz A. Łabuz

2014-01-01

Full Text Available The Polish coast is a non-tidal area; its shores are affected mainly by autumn-winter storm surges. Those of 6 and 14 January 2012 are representative of the forces driving the erosion of normally accumulative sections of coastal dunes, monitored by the author since 1997. The sea level maximum during these two storm surges reached 1.2 to 1.5 m amsl along the Polish coast. Land forms up to 3 m amsl were inundated. Beaches and low parts of the coast up to this height were rebuilt by sea waves attacking the coast for almost 12 days. Quantitative analyses of the morphological dynamics of the coastal dunes are presented for 57 profiles located along the coast. Only those accumulative sections of the Polish coast are analysed where sand accumulation did occur and led to new foredune development. The mean rate of dune erosion was 2.5 m3 per square metre with an average toe retreat of 1.4 m. Erosion understood as dune retreat was greater when a beach was lower (correlation coefficient 0.8. Dune erosion did not occur on coasts with beaches higher than 3.2 m or on lower ones covered by embryo dunes.

Modeling of Coastal Inundation, Storm Surge, and Relative Sea-Level Rise at Naval Station Norfolk, Norfolk, Virginia, USA

Science.gov (United States)

2013-01-01

Storm Surge, and Relative Sea-Level Rise at Naval Station Norfolk, Norfolk, Virginia, USA 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT...tive comments on the manuscript. Permission was granted by the Chief, USACE, to publish this information. LITERATURE CITED Blanton, B.; Stillwell, L...Geospatial Center. http://www.agc.army.mil/ (accessed February 29, 2012). Vickery, P.; Wadhera, D.; Cox, A.; Cardone , V.; Hanson, J., and Blanton, B

Sea level during storm surges as seen in tide-gauge records along the east coast of India

Digital Repository Service at National Institute of Oceanography (India)

Sundar, D.; Shankar, D.; Shetye, S.R.

and crossed the north Orissa coast later that day; it weakened and moved westward subsequent to landfall. Sea-level variations due to surges triggered by storm winds form a noise superimposed on the highly periodic tides, which have astronomical origins.... In the next section we describe the analysis used to 1326 CURRENT SCIENCE, VOL. 77, NO. 10, 25 NOVEMBER 1999 COMPUTATIONAL ENGINEERING SCIENCE Figure 1b. Astronomical tide and dehyphenminustided sea level during Event 1. The dark blue vertical lines...

Tree Mortality following Prescribed Fire and a Storm Surge Event in Slash Pine (Pinus elliottii var. densa Forests in the Florida Keys, USA

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Jay P. Sah

2010-01-01

Full Text Available In fire-dependent forests, managers are interested in predicting the consequences of prescribed burning on postfire tree mortality. We examined the effects of prescribed fire on tree mortality in Florida Keys pine forests, using a factorial design with understory type, season, and year of burn as factors. We also used logistic regression to model the effects of burn season, fire severity, and tree dimensions on individual tree mortality. Despite limited statistical power due to problems in carrying out the full suite of planned experimental burns, associations with tree and fire variables were observed. Post-fire pine tree mortality was negatively correlated with tree size and positively correlated with char height and percent crown scorch. Unlike post-fire mortality, tree mortality associated with storm surge from Hurricane Wilma was greater in the large size classes. Due to their influence on population structure and fuel dynamics, the size-selective mortality patterns following fire and storm surge have practical importance for using fire as a management tool in Florida Keys pinelands in the future, particularly when the threats to their continued existence from tropical storms and sea level rise are expected to increase.

Tree Mortality following Prescribed Fire and a Storm Surge Event in Slash Pine (Pinus elliottii var. densa) Forests in the Florida Keys, USA

International Nuclear Information System (INIS)

Sah, J.P.; Ross, M.S.; Ross, M.S.; Ogurcak, D.E.; Snyder, J.R.

2010-01-01

In fire-dependent forests, managers are interested in predicting the consequences of prescribed burning on post fire tree mortality. We examined the effects of prescribed fire on tree mortality in Florida Keys pine forests, using a factorial design with under story type, season, and year of burn as factors. We also used logistic regression to model the effects of burn season, fire severity, and tree dimensions on individual tree mortality. Despite limited statistical power due to problems in carrying out the full suite of planned experimental burns, associations with tree and fire variables were observed. Post-fire pine tree mortality was negatively correlated with tree size and positively correlated with char height and percent crown scorch. Unlike post-fire mortality, tree mortality associated with storm surge from Hurricane Wilma was greater in the large size classes. Due to their influence on population structure and fuel dynamics, the size-selective mortality patterns following fire and storm surge have practical importance for using fire as a management tool in Florida Keys pine lands in the future, particularly when the threats to their continued existence from tropical storms and sea level rise are expected to increase.

Tree mortality following prescribed fire and a storm surge event in Slash Pine (pinus elliottii var. densa) forests in the Florida Keys, USA

Science.gov (United States)

Sah, Jay P.; Ross, Michael S.; Snyder, James R.; Ogurcak, Danielle E.

2010-01-01

In fire-dependent forests, managers are interested in predicting the consequences of prescribed burning on postfire tree mortality. We examined the effects of prescribed fire on tree mortality in Florida Keys pine forests, using a factorial design with understory type, season, and year of burn as factors. We also used logistic regression to model the effects of burn season, fire severity, and tree dimensions on individual tree mortality. Despite limited statistical power due to problems in carrying out the full suite of planned experimental burns, associations with tree and fire variables were observed. Post-fire pine tree mortality was negatively correlated with tree size and positively correlated with char height and percent crown scorch. Unlike post-fire mortality, tree mortality associated with storm surge from Hurricane Wilma was greater in the large size classes. Due to their influence on population structure and fuel dynamics, the size-selective mortality patterns following fire and storm surge have practical importance for using fire as a management tool in Florida Keys pinelands in the future, particularly when the threats to their continued existence from tropical storms and sea level rise are expected to increase.

Analysis and simulation of propagule dispersal and salinity intrusion from storm surge on the movement of a marsh–mangrove ecotone in South Florida

Science.gov (United States)

Jiang, Jiang; DeAngelis, Donald L.; Anderson, Gordon H.; Smith, Thomas J.

2014-01-01

Coastal mangrove–freshwater marsh ecotones of the Everglades represent transitions between marine salt-tolerant halophytic and freshwater salt-intolerant glycophytic communities. It is hypothesized here that a self-reinforcing feedback, termed a “vegetation switch,” between vegetation and soil salinity, helps maintain the sharp mangrove–marsh ecotone. A general theoretical implication of the switch mechanism is that the ecotone will be stable to small disturbances but vulnerable to rapid regime shifts from large disturbances, such as storm surges, which could cause large spatial displacements of the ecotone. We develop a simulation model to describe the vegetation switch mechanism. The model couples vegetation dynamics and hydrologic processes. The key factors in the model are the amount of salt-water intrusion into the freshwater wetland and the passive transport of mangrove (e.g., Rhizophora mangle) viviparous seeds or propagules. Results from the model simulations indicate that a regime shift from freshwater marsh to mangroves is sensitive to the duration of soil salinization through storm surge overwash and to the density of mangrove propagules or seedlings transported into the marsh. We parameterized our model with empirical hydrologic data collected from the period 2000–2010 at one mangrove–marsh ecotone location in southwestern Florida to forecast possible long-term effects of Hurricane Wilma (24 October 2005). The model indicated that the effects of that storm surge were too weak to trigger a regime shift at the sites we studied, 50 km south of the Hurricane Wilma eyewall, but simulations with more severe artificial disturbances were capable of causing substantial regime shifts.

Tide-surge Interaction Intensified by the Taiwan Strait

Science.gov (United States)

Zhang, Wen-Zhou; Shi, Fengyan; Hong, Hua-Sheng; Shang, Shao-Ping; Kirby, James T.

2010-06-01

The Taiwan Strait is a long and wide shelf-channel where the hydrodynamics is extremely complex, being characterized by strong tides, and where storm surges frequently occur during the typhoon season. Obvious oscillations due to tide-surge interaction were observed by tide gauges along the northern Fujian coast, the west bank of the Taiwan Strait, during Typhoon Dan (1999). Numerical experiments indicate that nonlinear bottom friction (described by the quadratic formula) is a major factor to predict these oscillations while the nonlinear advective terms and the shallow water effect have little contribution. It is found that the tide-surge interaction in the northern portion of the Taiwan Strait is intensified by the strait. Simulations based on simplified topographies with and without the island of Taiwan show that, in the presence of the island, the channel effect strengthens tidal currents and tends to align the major axes of tidal ellipses along the channel direction. Storm-induced currents are also strengthened by the channel. The pattern of strong tidal currents and storm-induced currents along the channel direction enhances tide-surge interaction via the nonlinear bottom friction, resulting in the obvious oscillations along the northern Fujian coast.

A Two-Step Method to Select Major Surge-Producing Extratropical Cyclones from a 10,000-Year Stochastic Catalog

Science.gov (United States)

Keshtpoor, M.; Carnacina, I.; Yablonsky, R. M.

2016-12-01

Extratropical cyclones (ETCs) are the primary driver of storm surge events along the UK and northwest mainland Europe coastlines. In an effort to evaluate the storm surge risk in coastal communities in this region, a stochastic catalog is developed by perturbing the historical storm seeds of European ETCs to account for 10,000 years of possible ETCs. Numerical simulation of the storm surge generated by the full 10,000-year stochastic catalog, however, is computationally expensive and may take several months to complete with available computational resources. A new statistical regression model is developed to select the major surge-generating events from the stochastic ETC catalog. This regression model is based on the maximum storm surge, obtained via numerical simulations using a calibrated version of the Delft3D-FM hydrodynamic model with a relatively coarse mesh, of 1750 historical ETC events that occurred over the past 38 years in Europe. These numerically-simulated surge values were regressed to the local sea level pressure and the U and V components of the wind field at the location of 196 tide gauge stations near the UK and northwest mainland Europe coastal areas. The regression model suggests that storm surge values in the area of interest are highly correlated to the U- and V-component of wind speed, as well as the sea level pressure. Based on these correlations, the regression model was then used to select surge-generating storms from the 10,000-year stochastic catalog. Results suggest that roughly 105,000 events out of 480,000 stochastic storms are surge-generating events and need to be considered for numerical simulation using a hydrodynamic model. The selected stochastic storms were then simulated in Delft3D-FM, and the final refinement of the storm population was performed based on return period analysis of the 1750 historical event simulations at each of the 196 tide gauges in preparation for Delft3D-FM fine mesh simulations.

Tide-surge interaction along the east coast of the Leizhou Peninsula, South China Sea

Science.gov (United States)

Zhang, Heng; Cheng, Weicong; Qiu, Xixi; Feng, Xiangbo; Gong, Wenping

2017-06-01

A triply-nested two-dimensional (2D) ocean circulation model along with observed sea level records are used to study tide-surge interaction along the east coast of the Leizhou Peninsula (LP) which is characterized by extensive mudflats, large tidal ranges and a complex coastline. The dependency of surge maxima on the water level and the phase of tide are respectively investigated using two statistical approaches. Results show that tide-surge interaction along the east coast of the LP is significant, where surges peak 3-6 h before or after the nearest high water. The triply-nested 2D ocean circulation model is used to quantify tide-surge interaction in this region and to investigate its physical cause. The largest amplitudes of tide-surge interaction are found in the shallow water region of the Leizhou Bay, with values up to 1 m during typhoon events. Numerical experiments reveal that nonlinear bottom friction is the main contributor to tide-surge interaction, while the contribution of the nonlinear advective effect can be neglected. The shallow water effect enhances the role of nonlinear bottom friction in determining tide-surge modulation, leaving the surge peaks usually occur on the rising or falling tide. It is also found that the relative contribution of local wind and remote wind is different depending on the storm track and storm intensity, which would finally affect the temporal and spatial distribution of tide-surge interaction during typhoon events. These findings confirm the importance of coupling storm surges and tides for the prediction of storm surge events in regions which are characterized by shallow water depths and large tidal ranges.

Assessment of the Great Lakes Marine Renewable Energy Resources: Characterizing Lake Erie Surge, Seiche and Waves

Science.gov (United States)

Farhadzadeh, A.; Hashemi, M. R.

2016-02-01

Lake Erie, the fourth largest in surface area, smallest in volume and shallowest among the Great Lakes is approximately 400 km long and 90 km wide. Short term lake level variations are due to storm surge generated by high winds and moving pressure systems over the lake mainly in the southwest-northeast direction, along the lakes longitudinal axis. The historical wave data from three active offshore buoys shows that significant wave height can exceed 5 m in the eastern and central basins. The long-term lake level data show that storm surge can reach up to 3 m in eastern Lake Erie. Owing its shallow depth, Lake Erie frequently experiences seiching motions, the low frequency oscillations that are initiated by storm surge. The seiches whose first mode of oscillations has a period of nearly 14.2 hours can last from several hours to days. In this study, the Lake Erie potential for power generation, primarily using storm surge and seiche and also waves are assessed. Given the cyclic lake level variations due to storm-induced seiching, a concept similar to that of tidal range development is utilized to assess the potential of storm surge and seiche energy harvesting mechanisms for power generation. In addition, wave energy resources of the Lake is characterized -. To achieve these objectives, the following steps are taken : (1) Frequency of occurrence for extreme storm surge and wave events is determined using extreme value analysis such as Peak-Over-Threshold method for the long-term water level and wave data; (2) Spatial and temporal variations of wave height, storm surge and seiche are characterized. The characterization is carried out using the wave and storm surge outputs from numerical simulation of a number of historical extreme events. The coupled ADCIRC and SWAN model is utilized for the modeling; (3) Assessment of the potentials for marine renewable power generation in Lake Erie is made. The approach can be extended to the other lakes in the Great Lakes region.

Modelling sea level rise impacts on storm surges along US coasts

International Nuclear Information System (INIS)

Tebaldi, Claudia; Strauss, Benjamin H; Zervas, Chris E

2012-01-01

Sound policies for protecting coastal communities and assets require good information about vulnerability to flooding. Here, we investigate the influence of sea level rise on expected storm surge-driven water levels and their frequencies along the contiguous United States. We use model output for global temperature changes, a semi-empirical model of global sea level rise, and long-term records from 55 nationally distributed tidal gauges to develop sea level rise projections at each gauge location. We employ more detailed records over the period 1979–2008 from the same gauges to elicit historic patterns of extreme high water events, and combine these statistics with anticipated relative sea level rise to project changing local extremes through 2050. We find that substantial changes in the frequency of what are now considered extreme water levels may occur even at locations with relatively slow local sea level rise, when the difference in height between presently common and rare water levels is small. We estimate that, by mid-century, some locations may experience high water levels annually that would qualify today as ‘century’ (i.e., having a chance of occurrence of 1% annually) extremes. Today’s century levels become ‘decade’ (having a chance of 10% annually) or more frequent events at about a third of the study gauges, and the majority of locations see substantially higher frequency of previously rare storm-driven water heights in the future. These results add support to the need for policy approaches that consider the non-stationarity of extreme events when evaluating risks of adverse climate impacts. (letter)

A Case Study of Preliminary Cost-Benefit Analysis of Building Levees to Mitigate the Joint Effects of Sea Level Rise and Storm Surge

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Binbin Peng

2018-02-01

Full Text Available Sea-level rise (SLR will magnify the impacts of storm surge; the resulting severe flooding and inundation can cause huge damage to coastal communities. Community leaders are considering implementing adaptation strategies, typically hard engineering projects, to protect coastal assets and resources. It is important to understand the costs and benefits of the proposed project before any decision is made. To mitigate the flooding impact of joint effects of storm surge and SLR, building levee segments is chosen to be a corresponding adaptation strategy to protect the real estate assets in the study area—the City of Miami, FL, USA. This paper uses the classic Cost-Benefit Analysis (CBA to assess the cost efficiency and proposes corresponding improvements in the benefit estimation, by estimating the avoided damages of implementing levee projects. Results show that the city will benefit from implementing levee projects along the Miami River in both a one-time 10 year storm event with SLR and cumulative long-term damage scenarios. This study also suggests that conducting CBA is a critical process before making coastal adaptation planning investment. A more meaningful result of cost effectiveness is estimated by accounting for the appreciation and time value. In addition, a sensitivity analysis is conducted to verify how the choice of discount rate influences the result. Uncertain factors including the rate of SLR, storm intensification, land use changes, and real estate appreciation are further analyzed.

A Storm Surge and Inundation Model of the Back River Watershed at NASA Langley Research Center

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Loftis, Jon Derek; Wang, Harry V.; DeYoung, Russell J.

2013-01-01

This report on a Virginia Institute for Marine Science project demonstrates that the sub-grid modeling technology (now as part of Chesapeake Bay Inundation Prediction System, CIPS) can incorporate high-resolution Lidar measurements provided by NASA Langley Research Center into the sub-grid model framework to resolve detailed topographic features for use as a hydrological transport model for run-off simulations within NASA Langley and Langley Air Force Base. The rainfall over land accumulates in the ditches/channels resolved via the model sub-grid was tested to simulate the run-off induced by heavy precipitation. Possessing both the capabilities for storm surge and run-off simulations, the CIPS model was then applied to simulate real storm events starting with Hurricane Isabel in 2003. It will be shown that the model can generate highly accurate on-land inundation maps as demonstrated by excellent comparison of the Langley tidal gauge time series data (CAPABLE.larc.nasa.gov) and spatial patterns of real storm wrack line measurements with the model results simulated during Hurricanes Isabel (2003), Irene (2011), and a 2009 Nor'easter. With confidence built upon the model's performance, sea level rise scenarios from the ICCP (International Climate Change Partnership) were also included in the model scenario runs to simulate future inundation cases.

Application of SWAN+ADCIRC to tide-surge and wave simulation in Gulf of Maine during Patriot's Day storm

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Dong-mei Xie

2016-01-01

Full Text Available The southern coast of the Gulf of Maine in the United States is prone to flooding caused by nor'easters. A state-of-the-art fully-coupled model, the Simulating WAves Nearshore (SWAN model with unstructured grids and the ADvanced CIRCulation (ADCIRC model, was used to study the hydrodynamic response in the Gulf of Maine during the Patriot's Day storm of 2007, a notable example of nor'easters in this area. The model predictions agree well with the observed tide-surges and waves during this storm event. Waves and circulation in the Gulf of Maine were analyzed. The Georges Bank plays an important role in dissipating wave energy through the bottom friction when waves propagate over the bank from offshore to the inner gulf due to its shallow bathymetry. Wave energy dissipation results in decreasing significant wave height (SWH in the cross-bank direction and wave radiation stress gradient, which in turn induces changes in currents. While the tidal currents are dominant over the Georges Bank and in the Bay of Fundy, the residual currents generated by the meteorological forcing and waves are significant over the Georges Bank and in the coastal area and can reach 0.3 m/s and 0.2 m/s, respectively. In the vicinity of the coast, the longshore current generated by the surface wind stress and wave radiation stress acting parallel to the coastline is inversely proportional to the water depth and will eventually be limited by the bottom friction. The storm surge level reaches 0.8 m along the western periphery of the Gulf of Maine while the wave set-up due to radiation stress variation reaches 0.2 m. Therefore, it is significant to coastal flooding.

Tide-surge historical assessment of extreme water levels for the St. Johns River: 1928-2017

Science.gov (United States)

Bacopoulos, Peter

2017-10-01

An historical storm population is developed for the St. Johns River, located in northeast Florida-US east coast, via extreme value assessment of an 89-year-long record of hourly water-level data. Storm surge extrema and the corresponding (independent) storm systems are extracted from the historical record as well as the linear and nonlinear trends of mean sea level. Peaks-over-threshold analysis reveals the top 16 most-impactful (storm surge) systems in the general return-period range of 1-100 years. Hurricane Matthew (2016) broke the record with a new absolute maximum water level of 1.56 m, although the peak surge occurred during slack tide level (0.00 m). Hurricanes and tropical systems contribute to return periods of 10-100 years with water levels in the approximate range of 1.3-1.55 m. Extratropical systems and nor'easters contribute to the historical storm population (in the general return-period range of 1-10 years) and are capable of producing extreme storm surges (in the approximate range of 1.15-1.3 m) on par with those generated by hurricanes and tropical systems. The highest astronomical tide is 1.02 m, which by evaluation of the historical record can contribute as much as 94% to the total storm-tide water level. Statically, a hypothetical scenario of Hurricane Matthew's peak surge coinciding with the highest astronomical tide would yield an overall storm-tide water level of 2.58 m, corresponding to an approximate 1000-year return period by historical comparison. Sea-level trends (linear and nonlinear) impact water-level return periods and constitute additional risk hazard for coastal engineering designs.

Application of SWAN+ADCIRC to tide-surge and wave simulation in Gulf of Maine during Patriot’s Day storm

Directory of Open Access Journals (Sweden)

Dong-mei Xie

2016-01-01

Full Text Available The southern coast of the Gulf of Maine in the United States is prone to flooding caused by nor’easters. A state-of-the-art fully-coupled model, the Simulating WAves Nearshore (SWAN model with unstructured grids and the ADvanced CIRCulation (ADCIRC model, was used to study the hydrodynamic response in the Gulf of Maine during the Patriot’s Day storm of 2007, a notable example of nor’easters in this area. The model predictions agree well with the observed tide-surges and waves during this storm event. Waves and circulation in the Gulf of Maine were analyzed. The Georges Bank plays an important role in dissipating wave energy through the bottom friction when waves propagate over the bank from offshore to the inner gulf due to its shallow bathymetry. Wave energy dissipation results in decreasing significant wave height (SWH in the cross-bank direction and wave radiation stress gradient, which in turn induces changes in currents. While the tidal currents are dominant over the Georges Bank and in the Bay of Fundy, the residual currents generated by the meteorological forcing and waves are significant over the Georges Bank and in the coastal area and can reach 0.3 m/s and 0.2 m/s, respectively. In the vicinity of the coast, the longshore current generated by the surface wind stress and wave radiation stress acting parallel to the coastline is inversely proportional to the water depth and will eventually be limited by the bottom friction. The storm surge level reaches 0.8 m along the western periphery of the Gulf of Maine while the wave set-up due to radiation stress variation reaches 0.2 m. Therefore, it is significant to coastal flooding.

A probabilistic approach for assessing the vulnerability of transportation infrastructure to flooding from sea level rise and storm surge.

Science.gov (United States)

Douglas, E. M.; Kirshen, P. H.; Bosma, K.; Watson, C.; Miller, S.; McArthur, K.

2015-12-01

There now exists a plethora of information attesting to the reality of our changing climate and its impacts on both human and natural systems. There also exists a growing literature linking climate change impacts and transportation infrastructure (highways, bridges, tunnels, railway, shipping ports, etc.) which largely agrees that the nation's transportation systems are vulnerable. To assess this vulnerability along the coast, flooding due to sea level rise and storm surge has most commonly been evaluated by simply increasing the water surface elevation and then estimating flood depth by comparing the new water surface elevation with the topographic elevations of the land surface. While this rudimentary "bathtub" approach may provide a first order identification of potential areas of vulnerability, accurate assessment requires a high resolution, physically-based hydrodynamic model that can simulate inundation due to the combined effects of sea level rise, storm surge, tides and wave action for site-specific locations. Furthermore, neither the "bathtub" approach nor other scenario-based approaches can quantify the probability of flooding due to these impacts. We developed a high resolution coupled ocean circulation-wave model (ADCIRC/SWAN) that utilizes a Monte Carlo approach for predicting the depths and associated exceedance probabilities of flooding due to both tropical (hurricanes) and extra-tropical storms under current and future climate conditions. This required the development of an entirely new database of meteorological forcing (e.g. pressure, wind speed, etc.) for historical Nor'easters in the North Atlantic basin. Flooding due to hurricanes and Nor'easters was simulated separately and then composite flood probability distributions were developed. Model results were used to assess the vulnerability of the Central Artery/Tunnel system in Boston, Massachusetts to coastal flooding now and in the future. Local and regional adaptation strategies were

Coastal flooding: impact of waves on storm surge during extremes – a case study for the German Bight

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J. Staneva

2016-11-01

Full Text Available This study addresses the impact of wind, waves, tidal forcing and baroclinicity on the sea level of the German Bight during extreme storm events. The role of wave-induced processes, tides and baroclinicity is quantified, and the results are compared with in situ measurements and satellite data. A coupled high-resolution modelling system is used to simulate wind waves, the water level and the three-dimensional hydrodynamics. The models used are the wave model WAM and the circulation model GETM. The two-way coupling is performed via the OASIS3-MCT coupler. The effects of wind waves on sea level variability are studied, accounting for wave-dependent stress, wave-breaking parameterization and wave-induced effects on vertical mixing. The analyses of the coupled model results reveal a closer match with observations than for the stand-alone circulation model, especially during the extreme storm Xaver in December 2013. The predicted surge of the coupled model is significantly enhanced during extreme storm events when considering wave–current interaction processes. This wave-dependent approach yields a contribution of more than 30 % in some coastal areas during extreme storm events. The contribution of a fully three-dimensional model compared with a two-dimensional barotropic model showed up to 20 % differences in the water level of the coastal areas of the German Bight during Xaver. The improved skill resulting from the new developments justifies further use of the coupled-wave and three-dimensional circulation models in coastal flooding predictions.

Hurricane Sandy science plan: impacts of storm surge, including disturbed estuarine and bay hydrology

Science.gov (United States)

Caskie, Sarah A.

2013-01-01

Hurricane Sandy devastated some of the most heavily populated eastern coastal areas of the Nation. With a storm surge peaking at more than 19 feet, the powerful landscape-altering destruction of Hurricane Sandy is a stark reminder of why the Nation must become more resilient to coastal hazards. In response to this natural disaster, the U.S. Geological Survey (USGS) received a total of $41.2 million in supplemental appropriations from the Department of the Interior (DOI) to support response, recovery, and rebuilding efforts. These funds support a science plan that will provide critical scientific information necessary to inform management decisions for recovery of coastal communities, and aid in preparation for future natural hazards. This science plan is designed to coordinate continuing USGS activities with stakeholders and other agencies to improve data collection and analysis that will guide recovery and restoration efforts. The science plan is split into five distinct themes: • Coastal topography and bathymetry • Impacts to coastal beaches and barriers

Observations of Building Performance under Combined Wind and Surge Loading from Hurricane Harvey

Science.gov (United States)

Lombardo, F.; Roueche, D. B.; Krupar, R. J.; Smith, D. J.; Soto, M. G.

2017-12-01

Hurricane Harvey struck the Texas coastline on August 25, 2017, as a Category 4 hurricane - the first major hurricane to reach the US in twelve years. Wind gusts over 130 mph and storm surge as high as 12.5 ft caused widespread damage to buildings and critical infrastructure in coastal communities including Rockport, Fulton, Port Aransas and Aransas Pass. This study presents the methodology and preliminary observations of a coordinated response effort to document residential building performance under wind and storm surge loading. Over a twelve day survey period the study team assessed the performance of more than 1,000 individual, geo-located residential buildings. Assessments were logged via a smartphone application to facilitate rapid collection and collation of geotagged photographs, building attributes and structural details, and structural damage observations. Detailed assessments were also made of hazard intensity, specifically storm surge heights and both wind speed and direction indicators. Preliminary observations and findings will be presented, showing strong gradients in damage between inland and coastal regions of the affected areas that may be due in part to enhanced individual loading effects of wind and storm surge and potentially joint-hazard loading effects. Contributing factors to the many cases of disproportionate damage observed in close proximity will also be discussed. Ongoing efforts to relate building damage to near-surface hazard measurements (e.g., radar, anemometry) in close proximity will also be described.

Measuring storm tide and high-water marks caused by Hurricane Sandy in New York: Chapter 2

Science.gov (United States)

Simonson, Amy E.; Behrens, Riley

2015-01-01

In response to Hurricane Sandy, personnel from the U.S. Geological Survey (USGS) deployed a temporary network of storm-tide sensors from Virginia to Maine. During the storm, real-time water levels were available from tide gages and rapid-deployment gages (RDGs). After the storm, USGS scientists retrieved the storm-tide sensors and RDGs and surveyed high-water marks. These data demonstrate that the timing of peak storm surge relative to astronomical tide was extremely important in southeastern New York. For example, along the south shores of New York City and western Suffolk County, the peak storm surge of 6–9 ft generally coincided with the astronomical high tide, which resulted in substantial coastal flooding. In the Peconic Estuary and northern Nassau County, however, the peak storm surge of 9 ft and nearly 12 ft, respectively, nearly coincided with normal low tide, which helped spare these communities from more severe coastal flooding.

What caused the rise of water level in the battle of Luermen bay in 1661? Tsunami, Storm surge, or Tide?

Science.gov (United States)

Wu, Tso-Ren; Wu, Han; Tsai, Yu-Lin

2016-04-01

In 1661, Chinese navy led by General Zheng Chenggong at the end of Ming Dynasty had a naval battle against Netherlands. This battle was not only the first official sea warfare that China confronted the Western world, but also the only naval battle won by Chinese Navy so far. This event was important because it changed the fate of Taiwan until today. One of the critical points that General Zheng won the battle was entering Luermen bay unexpected. Luermen bay was and is an extreme shallow bay with a 2.1m maximum water depth during the high tide, which was not possible for a fleet of 20,000 marines to across. Therefore, no defense was deployed from the Netherlands side. However, plenty of historical literatures mentioned a strange phenomenon that helped Chinese warships entered the Luermen bay, the rise of water level. In this study, we will discuss the possible causes that might rise the water level, e.g. Tsunami, storm surge, and high tide. We analyzed it based on the knowledge of hydrodynamics. We performed the newly developed Impact Intensify Analysis (IIA) for finding the potential tsunami sources, and the COMCOT tsunami model was adopted for the nonlinear scenario simulations, associated with the high resolution bathymetry data. Both earthquake and mudslide tsunamis were inspected. Other than that, we also collected the information of tide and weather for identifying the effects form high tide and storm surge. After the thorough study, a scenario that satisfy most of the descriptions in the historical literatures will be presented. The results will explain the cause of mysterious event that changed the destiny of Taiwan.

Extreme storms, sea level rise, and coastal change: implications for infrastructure reliability in the Gulf of Mexico

Science.gov (United States)

Anarde, K.; Kameshwar, S.; Irza, N.; Lorenzo-Trueba, J.; Nittrouer, J. A.; Padgett, J.; Bedient, P. B.

2016-12-01

Predicting coastal infrastructure reliability during hurricane events is important for risk-based design and disaster planning, such as delineating viable emergency response routes. Previous research has focused on either infrastructure vulnerability to coastal flooding or the impact of changing sea level and landforms on surge dynamics. Here we investigate the combined impact of sea level, morphology, and coastal flooding on the reliability of highway bridges - the only access points between barrier islands and mainland communities - during future extreme storms. We forward model coastal flooding for static projections of geomorphic change using ADCIRC+SWAN. First-order parameters that are adjusted include sea level and elevation. These are varied for each storm simulation to evaluate relative impact on the reliability of bridges surrounding Freeport, TX. Simulated storms include both synthetic and historical events, which are classified by intensity using the storm's integrated kinetic energy, a metric for surge generation potential. Reliability is estimated through probability of failure - given wave and surge loads - and time inundated. Findings include that: 1) bridge reliability scales inversely with surge height, and 2) sea level rise reduces bridge reliability due to a monotonic increase in surge height. The impact of a shifting landscape on bridge reliability is more complex: barrier island rollback can increase or decrease inundation times for storms of different intensity due to changes in wind-setup and back-barrier bay interactions. Initial storm surge readily inundates the coastal landscape during large intensity storms, however the draining of inland bays following storm passage is significantly impeded by the barrier. From a coastal engineering standpoint, we determine that to protect critical infrastructure, efforts now implemented that nourish low-lying barriers may be enhanced by also armoring back-bay coastlines and elevating bridge approach

Are inundation limit and maximum extent of sand useful for differentiating tsunamis and storms? An example from sediment transport simulations on the Sendai Plain, Japan

Science.gov (United States)

Watanabe, Masashi; Goto, Kazuhisa; Bricker, Jeremy D.; Imamura, Fumihiko

2018-02-01

We examined the quantitative difference in the distribution of tsunami and storm deposits based on numerical simulations of inundation and sediment transport due to tsunami and storm events on the Sendai Plain, Japan. The calculated distance from the shoreline inundated by the 2011 Tohoku-oki tsunami was smaller than that inundated by storm surges from hypothetical typhoon events. Previous studies have assumed that deposits observed farther inland than the possible inundation limit of storm waves and storm surge were tsunami deposits. However, confirming only the extent of inundation is insufficient to distinguish tsunami and storm deposits, because the inundation limit of storm surges may be farther inland than that of tsunamis in the case of gently sloping coastal topography such as on the Sendai Plain. In other locations, where coastal topography is steep, the maximum inland inundation extent of storm surges may be only several hundred meters, so marine-sourced deposits that are distributed several km inland can be identified as tsunami deposits by default. Over both gentle and steep slopes, another difference between tsunami and storm deposits is the total volume deposited, as flow speed over land during a tsunami is faster than during a storm surge. Therefore, the total deposit volume could also be a useful proxy to differentiate tsunami and storm deposits.

Extreme storm surges in the south of Brazil: atmospheric conditions and shore erosion

Directory of Open Access Journals (Sweden)

Cláudia Klose Parise

2009-09-01

Full Text Available The region under study is regularly subject to the occurrence of storms associated with frontal systems and extratropical cyclones, since it is located near one of the cyclogenetic regions in South America. These storms can generate storm surges that cause anomalous high sea level rises on Cassino Beach. The use of reanalysis data along with an efficient technique for the location of the cyclone, using a vorticity threshold, has provided a new classification based upon the trajectories of events that produce positive sea level variation. Three patterns have been identified: 1 Cyclogenesis to the south of Argentina with displacement to the east and a trajectory between 47.5ºS and 57.5ºS; 2 Cyclogenesis to the south of Uruguay with displacement to the east and a trajectory between 35ºS and 42.5ºS; and 3 Cyclogenesis to the south of Uruguay with displacement to the southeast and a trajectory between 35ºS and 57.5ºS. Maximum water level elevation above the mean sea level and beach erosion were associated, respectively, with winter and summer storms. Cassino beach displayed a seasonal morphological behavior, with short periods of episodic erosion associated with winter storm events followed by long periods of accretion characterized by the dominance of fair weather conditions.Marés meteorológicas que geram sobre-elevações do nível do mar são freqüentes na costa do Rio Grande do Sul e respondem às variações ocorridas na atmosfera. Torna-se importante, dessa maneira, definir padrões meteorológicos sinóticos responsáveis por gerar eventos de marés meteorológicas intensas na Praia do Cassino como objetivo desse trabalho. O uso de dados de reanálise associados a uma técnica eficiente de localização do ciclone, aplicando o conceito de vorticidade, permitiu definir uma nova classificação com base na trajetória de ciclones extratropicais responsáveis pela subida do nível do mar. Três padrões de trajetórias foram

Hurricane Rita surge data, southwestern Louisiana and southeastern Texas, September to November 2005

Science.gov (United States)

McGee, Benton D.; Goree, Burl B.; Tollett, Roland W.; Woodward, Brenda K.; Kress, Wade H.

2006-01-01

Pressure transducers and high-water marks were used to document the inland water levels related to storm surge generated by Hurricane Rita in southwestern Louisiana and southeastern Texas. On September 22-23, 2005, an experimental monitoring network consisting of 47 pressure transducers (sensors) was deployed at 33 sites over an area of about 4,000 square miles to record the timing, extent, and magnitude of inland hurricane storm surge and coastal flooding. Sensors were programmed to record date and time, temperature, and barometric or water pressure. Water pressure was corrected for changes in barometric pressure and salinity. Elevation surveys using global-positioning systems and differential levels were used to relate all storm-surge water-level data, reference marks, benchmarks, sensor measuring points, and high-water marks to the North American Vertical Datum of 1988 (NAVD 88). The resulting data indicated that storm-surge water levels over 14 feet above NAVD 88 occurred at three locations and rates of water-level rise greater than 5 feet per hour occurred at three locations near the Louisiana coast. Quality-assurance measures were used to assess the variability and accuracy of the water-level data recorded by the sensors. Water-level data from sensors were similar to data from co-located sensors, permanent U.S. Geological Survey streamgages, and water-surface elevations performed by field staff. Water-level data from sensors at selected locations were compared to corresponding high-water mark elevations. In general, the water-level data from sensors were similar to elevations of high quality high-water marks, while reporting consistently higher than elevations of lesser quality high-water marks.

Parameter sensitivity and uncertainty analysis for a storm surge and wave model

Directory of Open Access Journals (Sweden)

L. A. Bastidas

2016-09-01

Full Text Available Development and simulation of synthetic hurricane tracks is a common methodology used to estimate hurricane hazards in the absence of empirical coastal surge and wave observations. Such methods typically rely on numerical models to translate stochastically generated hurricane wind and pressure forcing into coastal surge and wave estimates. The model output uncertainty associated with selection of appropriate model parameters must therefore be addressed. The computational overburden of probabilistic surge hazard estimates is exacerbated by the high dimensionality of numerical surge and wave models. We present a model parameter sensitivity analysis of the Delft3D model for the simulation of hazards posed by Hurricane Bob (1991 utilizing three theoretical wind distributions (NWS23, modified Rankine, and Holland. The sensitive model parameters (of 11 total considered include wind drag, the depth-induced breaking γB, and the bottom roughness. Several parameters show no sensitivity (threshold depth, eddy viscosity, wave triad parameters, and depth-induced breaking αB and can therefore be excluded to reduce the computational overburden of probabilistic surge hazard estimates. The sensitive model parameters also demonstrate a large number of interactions between parameters and a nonlinear model response. While model outputs showed sensitivity to several parameters, the ability of these parameters to act as tuning parameters for calibration is somewhat limited as proper model calibration is strongly reliant on accurate wind and pressure forcing data. A comparison of the model performance with forcings from the different wind models is also presented.

Assessment of storm surge disaster potential for the Andaman Islands

Digital Repository Service at National Institute of Oceanography (India)

Kumar, V.S.; RameshBabu, V.; Babu, M.T.; Dhinakaran, G.; Rajamanickam, G.V.

. Supporting volume 1: math- ematical modelling of cyclone surge and related flooding. In: Cy- clone Damage in Bangladesh. United Nations Centre for Regional Development, pp. 9–37. DHI (Danish Hydraulic Institute), 2002. MIKE 21 Coastal Hydrau- lics...

Using Direct Policy Search to Identify Robust Strategies in Adapting to Uncertain Sea Level Rise and Storm Surge

Science.gov (United States)

Garner, G. G.; Keller, K.

2017-12-01

Sea-level rise poses considerable risks to coastal communities, ecosystems, and infrastructure. Decision makers are faced with deeply uncertain sea-level projections when designing a strategy for coastal adaptation. The traditional methods have provided tremendous insight into this decision problem, but are often silent on tradeoffs as well as the effects of tail-area events and of potential future learning. Here we reformulate a simple sea-level rise adaptation model to address these concerns. We show that Direct Policy Search yields improved solution quality, with respect to Pareto-dominance in the objectives, over the traditional approach under uncertain sea-level rise projections and storm surge. Additionally, the new formulation produces high quality solutions with less computational demands than the traditional approach. Our results illustrate the utility of multi-objective adaptive formulations for the example of coastal adaptation, the value of information provided by observations, and point to wider-ranging application in climate change adaptation decision problems.

Hindcast storm events in the Bering Sea for the St. Lawrence Island and Unalakleet Regions, Alaska

Science.gov (United States)

Erikson, Li H.; McCall, Robert T.; van Rooijen, Arnold; Norris, Benjamin

2015-01-01

This study provides viable estimates of historical storm-induced water levels in the coastal communities of Gambell and Savoonga situated on St. Lawrence Island in the Bering Sea, as well as Unalakleet located at the head of Norton Sound on the western coast of Alaska. Gambell, Savoonga, and Unalakleet are small Native Villages that are regularly impacted by coastal storms but where little quantitative information about these storms exists. The closest continuous water-level gauge is at Nome, located more than 200 kilometers from both St. Lawrence Island and Unalakleet. In this study, storms are identified and quantified using historical atmospheric and sea-ice data and then used as boundary conditions for a suite of numerical models. The work includes storm-surge (temporary rise in water levels due to persistent strong winds and low atmospheric pressures) modeling in the Bering Strait region, as well as modeling of wave runup along specified sections of the coast in Gambell and Unalakleet. Modeled historical water levels are used to develop return periods of storm surge and storm surge plus wave runup at key locations in each community. It is anticipated that the results will fill some of the data void regarding coastal flood data in western Alaska and be used for production of coastal vulnerability maps and community planning efforts.

Projected sea level rise and changes in extreme storm surge and wave events during the 21st century in the region of Singapore

Science.gov (United States)

Cannaby, Heather; Palmer, Matthew D.; Howard, Tom; Bricheno, Lucy; Calvert, Daley; Krijnen, Justin; Wood, Richard; Tinker, Jonathan; Bunney, Chris; Harle, James; Saulter, Andrew; O'Neill, Clare; Bellingham, Clare; Lowe, Jason

2016-05-01

Singapore is an island state with considerable population, industries, commerce and transport located in coastal areas at elevations less than 2 m making it vulnerable to sea level rise. Mitigation against future inundation events requires a quantitative assessment of risk. To address this need, regional projections of changes in (i) long-term mean sea level and (ii) the frequency of extreme storm surge and wave events have been combined to explore potential changes to coastal flood risk over the 21st century. Local changes in time-mean sea level were evaluated using the process-based climate model data and methods presented in the United Nations Intergovernmental Panel on Climate Change Fifth Assessment Report (IPCC AR5). Regional surge and wave solutions extending from 1980 to 2100 were generated using ˜ 12 km resolution surge (Nucleus for European Modelling of the Ocean - NEMO) and wave (WaveWatchIII) models. Ocean simulations were forced by output from a selection of four downscaled ( ˜ 12 km resolution) atmospheric models, forced at the lateral boundaries by global climate model simulations generated for the IPCC AR5. Long-term trends in skew surge and significant wave height were then assessed using a generalised extreme value model, fit to the largest modelled events each year. An additional atmospheric solution downscaled from the ERA-Interim global reanalysis was used to force historical ocean model simulations extending from 1980 to 2010, enabling a quantitative assessment of model skill. Simulated historical sea-surface height and significant wave height time series were compared to tide gauge data and satellite altimetry data, respectively. Central estimates of the long-term mean sea level rise at Singapore by 2100 were projected to be 0.52 m (0.74 m) under the Representative Concentration Pathway (RCP)4.5 (8.5) scenarios. Trends in surge and significant wave height 2-year return levels were found to be statistically insignificant and/or physically

A numerical study on the effects of wave-current-surge interactions on the height and propagation of sea surface waves in Charleston Harbor during Hurricane Hugo 1989

Science.gov (United States)

Liu, Huiqing; Xie, Lian

2009-06-01

The effects of wave-current interactions on ocean surface waves induced by Hurricane Hugo in and around the Charleston Harbor and its adjacent coastal waters are examined by using a three-dimensional (3D) wave-current coupled modeling system. The 3D storm surge modeling component of the coupled system is based on the Princeton Ocean Model (POM), the wave modeling component is based on the third generation wave model, Simulating WAves Nearshore (SWAN), and the inundation model is adopted from [Xie, L., Pietrafesa, L. J., Peng, M., 2004. Incorporation of a mass-conserving inundation scheme into a three-dimensional storm surge model. J. Coastal Res., 20, 1209-1223]. The results indicate that the change of water level associated with the storm surge is the primary cause for wave height changes due to wave-surge interaction. Meanwhile, waves propagating on top of surge cause a feedback effect on the surge height by modulating the surface wind stress and bottom stress. This effect is significant in shallow coastal waters, but relatively small in offshore deep waters. The influence of wave-current interaction on wave propagation is relatively insignificant, since waves generally propagate in the direction of the surface currents driven by winds. Wave-current interactions also affect the surface waves as a result of inundation and drying induced by the storm. Waves break as waters retreat in regions of drying, whereas waves are generated in flooded regions where no waves would have occurred without the flood water.

Hurricane Rita and the destruction of Holly Beach, Louisiana: Why the chenier plain is vulnerable to storms

Science.gov (United States)

Sallenger, A.H.; Wright, C.W.; Doran, K.; Guy, K.; Morgan, K.

2009-01-01

Hurricane Rita devastated gulf-front communities along the western Louisiana coast in 2005. LIDAR (light detection and ranging) topographic surveys and aerial photography collected before and after the storm showed the loss of every structure within the community of Holly Beach. Average shoreline change along western Louisiana's 140-km-long impacted shore was -23.3 ?? 30.1 m of erosion, although shoreline change in Holly Beach was substantially less, and erosion was not pervasive where the structures were lost. Before the storm, peak elevations of the dunes, or berms in the absence of dunes, along the impacted shore averaged 1.6 m. The storm surge, which reached 3.5 m just east of Holly Beach, completely inundated the beach systems along the impacted western Louisiana shore. The high surge potential and low land elevations make this coast extremely vulnerable to hurricanes. In fact, most of the western Louisiana shore impacted by Rita will be completely inundated by the storm surge of a worst-case Saffi r-Simpson category 1 hurricane. All of this shore will be inundated by worst-case category 2-5 storms. ?? 2009 The Geological Society of America.

Coastal Storm Surge Analysis: Modeling System Validation. Report 4: Intermediate Submission No. 2.0

Science.gov (United States)

2013-07-01

Hurricane Isabel, Hurricane Ernesto, and Extratropical Storm Ida. Model skill was accessed by quantitative comparison of model output to wind, wave...25. Extratropical Storm Nor’Ida maximum wind speeds. ......................................................... 41  Figure 26. Extratropical Storm ...Nor’Ida wind validation stations. ........................................................ 42  Figure 27. Comparisons of Extratropical Storm Nor’Ida wind

Ensemble Kalman Filter data assimilation and storm surge experiments of tropical cyclone Nargis

Directory of Open Access Journals (Sweden)

Le Duc

2015-07-01

Full Text Available Data assimilation experiments on Myanmar tropical cyclone (TC, Nargis, using the Local Ensemble Transform Kalman Filter (LETKF method and the Japan Meteorological Agency (JMA non-hydrostatic model (NHM were performed to examine the impact of LETKF on analysis performance in real cases. Although the LETKF control experiment using NHM as its driving model (NHM–LETKF produced a weak vortex, the subsequent 3-day forecast predicted Nargis’ track and intensity better than downscaling from JMA's global analysis. Some strategies to further improve the final analysis were considered. They were sea surface temperature (SST perturbations and assimilation of TC advisories. To address SST uncertainty, SST analyses issued by operational forecast centres were used in the assimilation window. The use of a fixed source of SST analysis for each ensemble member was more effective in practice. SST perturbations were found to have slightly positive impact on the track forecasts. Assimilation of TC advisories could have a positive impact with a reasonable choice of its free parameters. However, the TC track forecasts exhibited northward displacements, when the observation error of intensities was underestimated in assimilation of TC advisories. The use of assimilation of TC advisories was considered in the final NHM–LETKF by choosing an appropriate set of free parameters. The extended forecast based on the final analysis provided meteorological forcings for a storm surge simulation using the Princeton Ocean Model. Probabilistic forecasts of the water levels at Irrawaddy and Yangon significantly improved the results in the previous studies.

Surging Seas Risk Finder: A Tool for Local-Scale Flood Risk Assessments in Coastal Cities

Science.gov (United States)

Kulp, S. A.; Strauss, B.

2015-12-01

Local decision makers in coastal cities require accurate, accessible, and thorough assessments of flood exposure risk within their individual municipality, in their efforts to mitigate against damage due to future sea level rise. To fill this need, we have developed Climate Central's Surging Seas Risk Finder, an interactive data toolkit which presents our sea level rise and storm surge analysis for every coastal town, city, county, and state within the USA. Using this tool, policy makers can easily zoom in on their local place of interest to receive a detailed flood risk assessment, which synthesizes a wide range of features including total population, socially vulnerable population, housing, property value, road miles, power plants, schools, hospitals, and many other critical facilities. Risk Finder can also be used to identify specific points of interest in danger of exposure at different flood levels. Additionally, this tool provides localized storm surge probabilities and sea level rise projections at tidal gauges along the coast, so that users can quickly understand the risk of flooding in their area over the coming decades.

Dynamic interactions between coastal storms and salt marshes: A review

Science.gov (United States)

Leonardi, Nicoletta; Carnacina, Iacopo; Donatelli, Carmine; Ganju, Neil K.; Plater, Andrew James; Schuerch, Mark; Temmerman, Stijn

2018-01-01

This manuscript reviews the progresses made in the understanding of the dynamic interactions between coastal storms and salt marshes, including the dissipation of extreme water levels and wind waves across marsh surfaces, the geomorphic impact of storms on salt marshes, the preservation of hurricanes signals and deposits into the sedimentary records, and the importance of storms for the long term survival of salt marshes to sea level rise. A review of weaknesses, and strengths of coastal defences incorporating the use of salt marshes including natural, and hybrid infrastructures in comparison to standard built solutions is then presented.Salt marshes are effective in dissipating wave energy, and storm surges, especially when the marsh is highly elevated, and continuous. This buffering action reduces for storms lasting more than one day. Storm surge attenuation rates range from 1.7 to 25 cm/km depending on marsh and storms characteristics. In terms of vegetation properties, the more flexible stems tend to flatten during powerful storms, and to dissipate less energy but they are also more resilient to structural damage, and their flattening helps to protect the marsh surface from erosion, while stiff plants tend to break, and could increase the turbulence level and the scour. From a morphological point of view, salt marshes are generally able to withstand violent storms without collapsing, and violent storms are responsible for only a small portion of the long term marsh erosion.Our considerations highlight the necessity to focus on the indirect long term impact that large storms exerts on the whole marsh complex rather than on sole after-storm periods. The morphological consequences of storms, even if not dramatic, might in fact influence the response of the system to normal weather conditions during following inter-storm periods. For instance, storms can cause tidal flats deepening which in turn promotes wave energy propagation, and exerts a long term

Dynamic interactions between coastal storms and salt marshes: A review

Science.gov (United States)

Leonardi, Nicoletta; Carnacina, Iacopo; Donatelli, Carmine; Ganju, Neil Kamal; Plater, Andrew James; Schuerch, Mark; Temmerman, Stijn

2018-01-01

This manuscript reviews the progresses made in the understanding of the dynamic interactions between coastal storms and salt marshes, including the dissipation of extreme water levels and wind waves across marsh surfaces, the geomorphic impact of storms on salt marshes, the preservation of hurricanes signals and deposits into the sedimentary records, and the importance of storms for the long term survival of salt marshes to sea level rise. A review of weaknesses, and strengths of coastal defences incorporating the use of salt marshes including natural, and hybrid infrastructures in comparison to standard built solutions is then presented. Salt marshes are effective in dissipating wave energy, and storm surges, especially when the marsh is highly elevated, and continuous. This buffering action reduces for storms lasting more than one day. Storm surge attenuation rates range from 1.7 to 25 cm/km depending on marsh and storms characteristics. In terms of vegetation properties, the more flexible stems tend to flatten during powerful storms, and to dissipate less energy but they are also more resilient to structural damage, and their flattening helps to protect the marsh surface from erosion, while stiff plants tend to break, and could increase the turbulence level and the scour. From a morphological point of view, salt marshes are generally able to withstand violent storms without collapsing, and violent storms are responsible for only a small portion of the long term marsh erosion. Our considerations highlight the necessity to focus on the indirect long term impact that large storms exerts on the whole marsh complex rather than on sole after-storm periods. The morphological consequences of storms, even if not dramatic, might in fact influence the response of the system to normal weather conditions during following inter-storm periods. For instance, storms can cause tidal flats deepening which in turn promotes wave energy propagation, and exerts a long term detrimental

Coupled wave and surge modelling for the eastern Irish Sea and implications for model wind-stress

Science.gov (United States)

Brown, Jennifer M.; Wolf, Judith

2009-05-01

We revisit the surge of November 1977, a storm event which caused damage on the Sefton coast in NW England. A hindcast has been made with a coupled surge-tide-wave model, to investigate whether a wave-dependent surface drag is necessary for accurate surge prediction, and also if this can be represented by an optimised Charnock parameter. The Proudman Oceanographic Laboratory Coastal Modelling System-Wave Model (POLCOMS-WAM) has been used to model combined tides, surges, waves and wave-current interaction in the Irish Sea on a 1.85 km grid. This period has been previously thoroughly studied, e.g. Jones and Davies [Jones, J.E., Davies, A.M., 1998. Storm surge computations for the Irish Sea using a three-dimensional numerical model including wave-current interaction. Continental Shelf Research 18(2), 201-251] and we build upon this previous work to validate the POLCOMS-WAM model to test the accuracy of surge elevation predictions in the study area. A one-way nested approach has been set up from larger scale models to the Irish Sea model. It was demonstrated that (as expected) swell from the North Atlantic does not have a significant impact in the eastern Irish Sea. To capture the external surge generated outside of the Irish Sea a (1/9° by 1/6°) model extending beyond the continental shelf edge was run using the POLCOMS model for tide and surge. The model results were compared with tide gauge observations around the eastern Irish Sea. The model was tested with different wind-stress formulations including Smith and Banke [Smith, S.D., Banke, E.G., 1975. Variation of the surface drag coefficient with wind speed. Quarterly Journal of the Royal Meteorology Society, 101(429), 665-673] and Charnock [Charnock, H., 1955. Wind-stress on a water surface. Quarterly Journal of the Royal Meteorological Society, 81(350), 639-640]. In order to get a single parameterisation that works with wave-coupling, the wave-derived surface roughness length has been imposed in the surge model

Storm tide monitoring during the blizzard of January 26-28, 2015, in eastern Massachusetts

Science.gov (United States)

Massey, Andrew J.; Verdi, Richard J.

2015-01-01

The U.S. Geological Survey (USGS) deployed a temporary monitoring network of six storm surge sensors and four barometric pressure sensors along the Atlantic coast in eastern Massachusetts, from Plymouth to Newburyport, before the blizzard of January 26–28, 2015 (Blizzard of January 2015), to record the timing and magnitude of storm tide at select locations where forecasters had predicted the potential for coastal flooding. Additionally, water-level data were recorded and transmitted in near real-time from four permanent USGS tidal stations—three on Cape Cod and one near the mouth of the Merrimack River in Newburyport. The storm surge sensors were deployed at previously established fixed sites outfitted with presurveyed mounting brackets. The mounting brackets were installed in 2014 as part of the USGS Surge, Wave, and Tide Hydrodynamic (SWaTH) Network (https://water.usgs.gov/floods/STN/), which was funded through congressional supplemental appropriations for the U.S. Department of the Interior after the devastating landfall of Hurricane Sandy on October 29, 2012 (Simmons and others, 2014). The USGS received this funding to enable better understanding of coastal flooding hazards in the region, to improve preparedness for future coastal storms, and to increase the resilience of coastal cities, infrastructure, and natural systems in the region (Buxton and others, 2013). The USGS established 163 monitoring locations along the New England coast for the SWaTH Network, including 70 sites in Massachusetts.

Integration of coastal inundation modeling from storm tides to individual waves

Science.gov (United States)

Li, Ning; Roeber, Volker; Yamazaki, Yoshiki; Heitmann, Troy W.; Bai, Yefei; Cheung, Kwok Fai

2014-11-01

Modeling of storm-induced coastal inundation has primarily focused on the surge generated by atmospheric pressure and surface winds with phase-averaged effects of the waves as setup. Through an interoperable model package, we investigate the role of phase-resolving wave processes in simulation of coastal flood hazards. A spectral ocean wave model describes generation and propagation of storm waves from deep to intermediate water, while a non-hydrostatic storm-tide model has the option to couple with a spectral coastal wave model for computation of phase-averaged processes in a near-shore region. The ocean wave and storm-tide models can alternatively provide the wave spectrum and the surface elevation as the boundary and initial conditions for a nested Boussinesq model. Additional surface-gradient terms in the Boussinesq equations maintain the quasi-steady, non-uniform storm tide for modeling of phase-resolving surf and swash-zone processes as well as combined tide, surge, and wave inundation. The two nesting schemes are demonstrated through a case study of Hurricane Iniki, which made landfall on the Hawaiian Island of Kauai in 1992. With input from a parametric hurricane model and global reanalysis and tidal datasets, the two approaches produce comparable significant wave heights and phase-averaged surface elevations in the surf zone. The nesting of the Boussinesq model provides a seamless approach to augment the inundation due to the individual waves in matching the recorded debris line along the coast.

Cost-efficient and storm surge-sensitive bridge design for coastal Maine.

Science.gov (United States)

2013-08-01

Climatic variation felt through changing weather patterns is having increasingly acute effects on Maines : transportation infrastructure. Acute risk occurs as a result of events, such as storms and flooding, while chronic risk : surrounds longer r...

Increasing Flood Risk due to Run-off Outflow near Estuarine City during Storm Event

Science.gov (United States)

Son, S.; Lee, C.; Do, K.; Jung, T.

2017-12-01

Tropical cyclone easily causes inundation damage to low-lying coastal area and the damage may be amplified due to tide motion, sea-level rise, riverine discharges. Specifically, typhoons are accompanied by intensive rainfall, which will of course raise the river water level and thus enhance the flooding damages. If the tidal cycle coincides the high water, flooding will be even aggravated. In the present study, we simulated storm surge motions at the coastal area considering combined effects of tidal and river discharge with aim to improve the accuracy of flooding prediction. The quasi 3-dimension ocean circulation model, Delf3D was used which solves the unsteady shallow water equation in the 2D and 3D. Since Delft3D is much applicable to accommodate the indirect flooding factors such as riverine discharge and short waves, outer-coupled modeling system was established to account for combined tide-surge-riverine discharge effects. In such integrated system, 11 tidal constituents were input as open boundary condition using TPXO 7.2 model, while the water level per unit time was preliminary calculated by HEC-HMS model and input as the upstream boundary conditions for river inside the domain. Typhoon MAEMI which attacked Masan city located at southern coast of South Korea and caused severe inundation damages in 2003 was selected for the study event. Basic information for typhoon such as path, wind speed, atmospheric pressure every 3 hours was provided by the Korea Meteorological Agency and was adopted. The simulation was implemented with tide and storm surge boundary conditions focusing on the target area, Masan, while the additional consideration on the discharge of the river inside the domain was also made. Simulated water level at the fixed location was compared to the observation for its verification and the extent of inundation areas of Masan were compared between observed and calculated. The marginal contribution of riverine discharge on the flooding area

Mangroves can provide protection against wind damage during storms

Science.gov (United States)

Das, Saudamini; Crépin, Anne-Sophie

2013-12-01

Research has established that mangroves can protect lives and property from storms by buffering the impacts of storm surges. However, their effects in attenuating wind velocity and providing protection from wind damage during storms are not known. This study examined whether mangroves attenuate damage from cyclonic winds and found that they provide substantial protection to properties, even relatively far away from mangroves and the coast. We devised a theoretical model of wind protection by mangroves and calibrated and applied this model using data from the 1999 cyclone in the Odisha region of India. The model predicted and quantified the actual level of damage reasonably accurately and showed that mangroves reduced wind damage to houses. The wind protection value of mangroves in reducing house damage amounted to approximately US$177 per hectare at 1999 prices. This provides additional evidence of the storm protection ecosystem services that mangroves supply in the region and an additional reason to invest in mangrove ecosystems to provide better adaptability to coastal disasters such as storms.

Dune recovery after storm erosion on a high-energy beach: Vougot Beach, Brittany (France)

Science.gov (United States)

Suanez, Serge; Cariolet, Jean-Marie; Cancouët, Romain; Ardhuin, Fabrice; Delacourt, Christophe

2012-02-01

On 10th March 2008, the high energy storm Johanna hit the French Atlantic coast, generating severe dune erosion on Vougot Beach (Brittany, France). In this paper, the recovery of the dune of Vougot Beach is analysed through a survey of morphological changes and hydrodynamic conditions. Data collection focused on the period immediately following storm Johanna until July 2010, i.e. over two and a half years. Results showed that the dune retreated by a maximum of almost 6 m where storm surge and wave attack were the most energetic. Dune retreat led to the creation of accommodation space for the storage of sediment by widening and elevating space between the pre- and post-storm dune toe, and reducing impacts of the storm surge. Dune recovery started in the month following the storm event and is still ongoing. It is characterised by the construction of "secondary" embryo dunes, which recovered at an average rate of 4-4.5 cm per month, although average monthly volume changes varied from - 1 to 2 m 3.m - 1 . These embryo dunes accreted due to a large aeolian sand supply from the upper tidal beach to the existing foredune. These dune-construction processes were facilitated by growth of vegetation on low-profile embryo dunes promoting backshore accretion. After more than two years of survey, the sediment budget of the beach/dune system showed that more than 10,000 m 3 has been lost by the upper tidal beach. We suggest that seaward return currents generated during the storm of 10th March 2008 are responsible for offshore sediment transport. Reconstitution of the equilibrium beach profile following the storm event may therefore have generated cross-shore sediment redistribution inducing net erosion in the tidal zone.

Developing Local Scale, High Resolution, Data to Interface with Numerical Storm Models

Science.gov (United States)

Witkop, R.; Becker, A.; Stempel, P.

2017-12-01

High resolution, physical storm models that can rapidly predict storm surge, inundation, rainfall, wind velocity and wave height at the intra-facility scale for any storm affecting Rhode Island have been developed by Researchers at the University of Rhode Island's (URI's) Graduate School of Oceanography (GSO) (Ginis et al., 2017). At the same time, URI's Marine Affairs Department has developed methods that inhere individual geographic points into GSO's models and enable the models to accurately incorporate local scale, high resolution data (Stempel et al., 2017). This combination allows URI's storm models to predict any storm's impacts on individual Rhode Island facilities in near real time. The research presented here determines how a coastal Rhode Island town's critical facility managers (FMs) perceive their assets as being vulnerable to quantifiable hurricane-related forces at the individual facility scale and explores methods to elicit this information from FMs in a format usable for incorporation into URI's storm models.

Storm surges in the Singapore Strait due to winds in the South China Sea

Digital Repository Service at National Institute of Oceanography (India)

Tkalich, P.; Vethamony, P.; Babu, M.T.; Malanotte-Rizzoli, P.

on the north, Karimata Strait on the south, east cost of Peninsular Malaysia on the west, and break of Sunda Shelf on the east, could experience positive or negative SLAs depending on the wind direction and speed. Strong sea level surges during NE monsoon...

Positive and negative ionospheric storms occurring during the 15 May 2005 geomagnetic superstorm

Science.gov (United States)

Horvath, Ildiko; Lovell, Brian C.

2015-09-01

This study focuses on the 15 May 2005 geomagnetic superstorm and aims to investigate the global variation of positive and negative storm phases and their development. Observations are provided by a series of global total electron content maps and multi-instrument line plots. Coupled Thermosphere-Ionosphere-Plasmasphere electrodynamics (CTIPe) simulations are also employed. Results reveal some sunward streaming plumes of storm-enhanced density (SED) over Asia and a well-developed midlatitude trough over North America forming isolated positive and negative storms, respectively. The simultaneous development of positive and negative storms over North America is also shown. Then, some enhanced auroral ionizations maintained by strong equatorward neutral winds appeared in the depleted nighttime ionosphere. Meanwhile, the northern nighttime polar region became significantly depleted as the SED plume plasma could not progress further than the dayside cusp. Oppositely, a polar tongue of ionization (TOI) developed in the daytime southern polar region. According to CTIP simulations, solar heating locally maximized (minimized) over the southern (northern) magnetic pole. Furthermore, strong upward surges of molecular-rich air created O/N2 decreases both in the auroral zone and in the trough region, while some SED-related downward surges produced O/N2 increases. From these results we conclude for the time period studied that (1) composition changes contributed to the formation of positive and negative storms, (2) strengthening polar convection and increasing solar heating of the polar cap supported polar TOI development, and (3) a weaker polar convection and minimized solar heating of the polar cap aided the depletion of polar plasma.

Predicting severe winter coastal storm damage

International Nuclear Information System (INIS)

Hondula, David M; Dolan, Robert

2010-01-01

Over the past 40 years residents of, and visitors to, the North Carolina coastal barrier islands have experienced the destructive forces of several 'named' extratropical storms. These storms have caused large-scale redistributions of sand and loss of coastal structures and infrastructure. While most of the population living on the islands are familiar with the wintertime storms, the damage and scars of the 'super northeasters'-such as the Ash Wednesday storm of 7 March 1962, and the Halloween storm of 1989-are slipping away from the public's memory. In this research we compared the damage zones of the 1962 Ash Wednesday storm, as depicted on aerial photographs taken after the storm, with photos taken of the same areas in 2003. With these high-resolution aerial photos we were able to estimate the extent of new development which has taken place along the Outer Banks of North Carolina since 1962. Three damage zones were defined that extend across the islands from the ocean landward on the 1962 aerial photos: (1) the zone of almost total destruction on the seaward edge of the islands where the storm waves break; (2) the zone immediately inland where moderate structural damage occurs during severe storms; and (3) the zone of flood damage at the landward margin of the storm surge and overwash. We considered the rate of coastal erosion, the rate of development, and increases in property values as factors which may contribute to changing the financial risk for coastal communities. In comparing the values of these four factors with the 1962 damage data, we produced a predicted dollar value for storm damage should another storm of the magnitude of the 1962 Ash Wednesday storm occur in the present decade. This model also provides an opportunity to estimate the rate of increase in the potential losses through time as shoreline erosion continues to progressively reduce the buffer between the development and the edge of the sea. Our data suggest that the losses along the North

Predicting severe winter coastal storm damage

Energy Technology Data Exchange (ETDEWEB)

Hondula, David M; Dolan, Robert, E-mail: hondula@virginia.edu [Department of Environmental Sciences, University of Virginia, PO Box 400123, Charlottesville, VA 22903 (United States)

2010-07-15

Over the past 40 years residents of, and visitors to, the North Carolina coastal barrier islands have experienced the destructive forces of several 'named' extratropical storms. These storms have caused large-scale redistributions of sand and loss of coastal structures and infrastructure. While most of the population living on the islands are familiar with the wintertime storms, the damage and scars of the 'super northeasters'-such as the Ash Wednesday storm of 7 March 1962, and the Halloween storm of 1989-are slipping away from the public's memory. In this research we compared the damage zones of the 1962 Ash Wednesday storm, as depicted on aerial photographs taken after the storm, with photos taken of the same areas in 2003. With these high-resolution aerial photos we were able to estimate the extent of new development which has taken place along the Outer Banks of North Carolina since 1962. Three damage zones were defined that extend across the islands from the ocean landward on the 1962 aerial photos: (1) the zone of almost total destruction on the seaward edge of the islands where the storm waves break; (2) the zone immediately inland where moderate structural damage occurs during severe storms; and (3) the zone of flood damage at the landward margin of the storm surge and overwash. We considered the rate of coastal erosion, the rate of development, and increases in property values as factors which may contribute to changing the financial risk for coastal communities. In comparing the values of these four factors with the 1962 damage data, we produced a predicted dollar value for storm damage should another storm of the magnitude of the 1962 Ash Wednesday storm occur in the present decade. This model also provides an opportunity to estimate the rate of increase in the potential losses through time as shoreline erosion continues to progressively reduce the buffer between the development and the edge of the sea. Our data suggest that the

Predicting severe winter coastal storm damage

Science.gov (United States)

Hondula, David M.; Dolan, Robert

2010-07-01

Over the past 40 years residents of, and visitors to, the North Carolina coastal barrier islands have experienced the destructive forces of several 'named' extratropical storms. These storms have caused large-scale redistributions of sand and loss of coastal structures and infrastructure. While most of the population living on the islands are familiar with the wintertime storms, the damage and scars of the 'super northeasters'—such as the Ash Wednesday storm of 7 March 1962, and the Halloween storm of 1989—are slipping away from the public's memory. In this research we compared the damage zones of the 1962 Ash Wednesday storm, as depicted on aerial photographs taken after the storm, with photos taken of the same areas in 2003. With these high-resolution aerial photos we were able to estimate the extent of new development which has taken place along the Outer Banks of North Carolina since 1962. Three damage zones were defined that extend across the islands from the ocean landward on the 1962 aerial photos: (1) the zone of almost total destruction on the seaward edge of the islands where the storm waves break; (2) the zone immediately inland where moderate structural damage occurs during severe storms; and (3) the zone of flood damage at the landward margin of the storm surge and overwash. We considered the rate of coastal erosion, the rate of development, and increases in property values as factors which may contribute to changing the financial risk for coastal communities. In comparing the values of these four factors with the 1962 damage data, we produced a predicted dollar value for storm damage should another storm of the magnitude of the 1962 Ash Wednesday storm occur in the present decade. This model also provides an opportunity to estimate the rate of increase in the potential losses through time as shoreline erosion continues to progressively reduce the buffer between the development and the edge of the sea. Our data suggest that the losses along the

Impact of Cyclone Track Features and Tidal Phase Shift upon Surge Characteristics in the Bay of Bengal along the Bangladesh Coast

Directory of Open Access Journals (Sweden)

Mohammad Asad Hussain

2017-11-01

Full Text Available The impact of cyclone track features (e.g., cyclone translation speed, cyclone path and cyclone landfall crossing angle in combination with tidal phase shift upon surge characteristics have been investigated at the Bay of Bengal along the Bangladesh coast. A two-dimensional hydrodynamic model in a horizontal direction (2DH coupled with a storm-surge model has been employed for the study. Numerical experiments with three different cyclone translation speeds show that when the surge height is directly forced by the cyclonic wind speed especially within the RWM (Radius of Maximum Wind, faster translation speed produces reduced surge height as the cyclone gets less time to force the water. On the other hand, at locations outside the RMW, surge waves travel as a propagating long wave where higher surges are produced by faster moving cyclones. It is found that surge arrival times are more and more affected by tidal phase when cyclone translation speed is reduced. Analysis of seven hypothetical parallel cyclone paths show that local bathymetry and complex coastline configurations strongly influence the surge height and surge arrival time along the Bangladesh coast. From the analyses of cyclone landfall crossing angles at the Khulna and Chittagong coasts, it is observed that surge durations are the smallest at both the coasts when the coastline crossing angles are the smallest.

Measuring and building resilience after big storms: Lessons learned from Super-Storm Sandy for the Harvey, Irma, Jose, and Maria coasts

Science.gov (United States)

Murdoch, P. S.; Penn, K. M.; Taylor, S. M.; Subramanian, B.; Bennett, R.

2017-12-01

As we recover from recent large storms, we need information to support increased environmental and socio-economic resilience of the Nation's coasts. Defining baseline conditions, tracking effects of mitigation actions, and measuring the uncertainty of resilience to future disturbance are essential so that the best management practices can be determined. The US Dept. of the Interior invested over $787 million dollars in 2013 to understand and mitigate coastal storm vulnerabilities and enhance resilience of the Northeast coast following Super-Storm Sandy. Several lessons-learned from that investment have direct application to mitigation and restoration needs following Hurricanes Harvey, Irma, Jose and Maria. New models of inundation, overwash, and erosion, developed during the Sandy projects have already been applied to coastlines before and after these recent storms. Results from wetland, beach, back-bay, estuary, and built-environment projects improved models of inundation and erosion from surge and waves. Tests of nature-based infrastructure for mitigating coastal disturbance yielded new concepts for best-practices. Ecological and socio-economic measurements established for detecting disturbance and tracking recovery provide baseline data critical to early detection of vulnerabilities. The Sandy lessons and preliminary applications on the recent storms could help define best-resilience practices before more costly mitigation or restoration efforts are required.

Scale-dependent behavior of the foredune: Implications for barrier island response to storms and sea-level rise

Science.gov (United States)

Houser, Chris; Wernette, Phil; Weymer, Bradley A.

2018-02-01

The impact of storm surge on a barrier island tends to be considered from a single cross-shore dimension, dependent on the relative elevations of the storm surge and dune crest. However, the foredune is rarely uniform and can exhibit considerable variation in height and width at a range of length scales. In this study, LiDAR data from barrier islands in Texas and Florida are used to explore how shoreline position and dune morphology vary alongshore, and to determine how this variability is altered or reinforced by storms and post-storm recovery. Wavelet analysis reveals that a power law can approximate historical shoreline change across all scales, but that storm-scale shoreline change ( 10 years) and dune height exhibit similar scale-dependent variations at swash and surf zone scales (< 1000 m). The in-phase nature of the relationship between dune height and storm-scale shoreline change indicates that areas of greater storm-scale shoreline retreat are associated with areas of smaller dunes. It is argued that the decoupling of storm-scale and historical shoreline change at swash and surf zone scales is also associated with the alongshore redistribution of sediment and the tendency of shorelines to evolve to a more diffusive (or straight) pattern with time. The wavelet analysis of the data for post-storm dune recovery is also characterized by red noise at the smallest scales characteristic of diffusive systems, suggesting that it is possible that small-scale variations in dune height can be repaired through alongshore recovery and expansion if there is sufficient time between storms. However, the time required for dune recovery exceeds the time between storms capable of eroding and overwashing the dune. Correlation between historical shoreline retreat and the variance of the dune at swash and surf zone scales suggests that the persistence of the dune is an important control on transgression through island migration or shoreline retreat with relative sea-level rise.

Analysis of storm-tide impacts from Hurricane Sandy in New York

Science.gov (United States)

Schubert, Christopher E.; Busciolano, Ronald J.; Hearn, Paul P.; Rahav, Ami N.; Behrens, Riley; Finkelstein, Jason S.; Monti, Jack; Simonson, Amy E.

2015-07-21

The hybrid cyclone-nor’easter known as Hurricane Sandy affected the mid-Atlantic and northeastern United States during October 28-30, 2012, causing extensive coastal flooding. Prior to storm landfall, the U.S. Geological Survey (USGS) deployed a temporary monitoring network from Virginia to Maine to record the storm tide and coastal flooding generated by Hurricane Sandy. This sensor network augmented USGS and National Oceanic and Atmospheric Administration (NOAA) networks of permanent monitoring sites that also documented storm surge. Continuous data from these networks were supplemented by an extensive post-storm high-water-mark (HWM) flagging and surveying campaign. The sensor deployment and HWM campaign were conducted under a directed mission assignment by the Federal Emergency Management Agency (FEMA). The need for hydrologic interpretation of monitoring data to assist in flood-damage analysis and future flood mitigation prompted the current analysis of Hurricane Sandy by the USGS under this FEMA mission assignment.

Towards a record of Holocene tsunami and storms for northern Hawke's Bay, New Zealand

International Nuclear Information System (INIS)

Cochran, U.A.; Berryman, K.R.; Mildenhall, D.C.; Hayward, B.W.; Southall, K.; Hollis, C.J.

2005-01-01

Eleven sand layers occur within Holocene low-energy estuarine and marginal marine sequences of blue-grey silty clay at two sites on the coastal plain between Wairoa and Mahia Peninsula, northern Hawke's Bay, New Zealand. The sedimentology and fossil assemblages of these layers are consistent with deposition by high-energy influxes to the sites. Three influxes are terrestrial in nature and are thought to represent alluvial flood events. All other sand layers are marine derived and are likely to be the result of storm surges or tsunami. Tsunami inundation is favoured for two sand layers that occur in association with evidence for sudden subsidence at c. 6300 and c. 4800 yr BP. The c. 6300 yr inundation also coincides with previously identified evidence for a tsunami at a site 10 km westwards along the coast. Further investigation is required to distinguish between tsunami and storm surge deposition for the remaining six layers. (author). 50 refs., 4 figs., 2 tabs

Centrifugal Compressor Surge Controlled

Science.gov (United States)

Skoch, Gary J.

2003-01-01

It shows the variation in compressor mass flow with time as the mass flow is throttled to drive the compressor into surge. Surge begins where wide variations in mass flow occur. Air injection is then turned on to bring about a recovery from the initial surge condition and stabilize the compressor. The throttle is closed further until surge is again initiated. Air injection is increased to again recover from the surge condition and stabilize the compressor.

Ionosphere and thermosphere responses during August 1972 storms - a review

International Nuclear Information System (INIS)

Matsushita, S.

1976-01-01

Various reports of ionospheric responses during the August 1972 storm events are reviewed with respect to the phenomena in three major world sectors, N-S America, Afro-Europe, and Austro-Asia, in order to have a global picture. Emphasized highlights are (1) extensive investigation of the sudden increase of the total electron content estimated from Faraday-rotation measurements of satellite signals; (2) a dramatic upward surge above 300 km latitude, soon after a flare, measured by the Millstone Hill incoherent scatter radar; (3) electron density profiles, electric fields and conductivities, and neutral winds, at the time of the geomagnetic storm sudden commencement and during the succeeding storms, measured by the Chatanika incoherent scatter radar; and, (4) approximately 2.5-h oscillatory F2 density variations in Eastern Asia during the F2 storm main phase. To show temporal variations of the latitudinal distributions of storm-time F2 electron densities, in three longitudinal sectors separated about 60 0 longitude each, newly investigated results of the F2 hourly data at 35 stations in the Asia-Australia-Pacific sector are then exhibited. Finally, current theories or at least theoretical ideas of ionospheric storm mechanisms are briefly introduced, and a few remarks on the August events in the light of those theories are presented. (Auth.)

Influence of Sea-Level Rise and Storms on Soil Accretion Rates in the Mangrove Forests of Everglades National Park, USA

Science.gov (United States)

Smoak, J. M.; Breithaupt, J.; Smith, T., III; Sanders, C. J.; Peterson, L. C.

2014-12-01

Mangrove forests provide a range of valuable ecosystem services including sequestering large quantities of organic carbon (OC) in their soils at rates higher than other forests. Whether or not mangrove soils continue to be a sink for OC will be determined by the mangrove ecosystems' response to climate change-induced stressors. The threats of rising sea level outpacing mangrove forest soil accretion and increased wave energy associated with this rise may become the primary climate change-induced stressors on mangrove ecosystems. The threat from wave energy is amplified during storm events, which could increasingly damage mangrove forests along the coastline. However, storms may enhance accretion rates at some sites due to delivery of storm surge material, which could increase the system's ability to keep pace with sea-level rise (SLR). To investigate these processes we measure soil accretion rates over the last 100 years (via 210Pb dating) within the mangrove forests of Everglades National Park, which are situated within the largest contiguous mangrove forest in North America. Accretion rates range from 2 to 2.8 mm per year for sites within 10 km of the Gulf of Mexico. These rates match (within error) or exceed SLR over the last 100 years. Sites farther inland than 10 km have slightly lower accretion rates. Throughout the system organic matter accumulation is the most important source material contributing to accretion. The more seaward sites also show an important contribution from carbonate material. Soil cores from the most seaward sites exhibited visual laminations and Ca peaks (determined via x-ray fluorescence). These are indicators of storm surge deposits. While higher sea level might produce more damage and loss of mangrove forest along open water (e.g., Gulf of Mexico), our findings suggest some sites will have enhanced accretion rates due to supplementation with storm surge material.

Evaluation of weather forecast systems for storm surge modeling in the Chesapeake Bay

Science.gov (United States)

Garzon, Juan L.; Ferreira, Celso M.; Padilla-Hernandez, Roberto

2018-01-01

Accurate forecast of sea-level heights in coastal areas depends, among other factors, upon a reliable coupling of a meteorological forecast system to a hydrodynamic and wave system. This study evaluates the predictive skills of the coupled circulation and wind-wave model system (ADCIRC+SWAN) for simulating storm tides in the Chesapeake Bay, forced by six different products: (1) Global Forecast System (GFS), (2) Climate Forecast System (CFS) version 2, (3) North American Mesoscale Forecast System (NAM), (4) Rapid Refresh (RAP), (5) European Center for Medium-Range Weather Forecasts (ECMWF), and (6) the Atlantic hurricane database (HURDAT2). This evaluation is based on the hindcasting of four events: Irene (2011), Sandy (2012), Joaquin (2015), and Jonas (2016). By comparing the simulated water levels to observations at 13 monitoring stations, we have found that the ADCIR+SWAN System forced by the following: (1) the HURDAT2-based system exhibited the weakest statistical skills owing to a noteworthy overprediction of the simulated wind speed; (2) the ECMWF, RAP, and NAM products captured the moment of the peak and moderately its magnitude during all storms, with a correlation coefficient ranging between 0.98 and 0.77; (3) the CFS system exhibited the worst averaged root-mean-square difference (excepting HURDAT2); (4) the GFS system (the lowest horizontal resolution product tested) resulted in a clear underprediction of the maximum water elevation. Overall, the simulations forced by NAM and ECMWF systems induced the most accurate results best accuracy to support water level forecasting in the Chesapeake Bay during both tropical and extra-tropical storms.

Flood Losses Associated with Winter Storms in the U.S. Northeast

Science.gov (United States)

Ting, M.; Shimkus, C.

2015-12-01

Winter storms pose a number of hazards to coastal communities in the U.S. Northeast including heavy rain, snow, strong wind, cold temperatures, and flooding. These hazards can cause millions in property damages from one storm alone. This study addresses the impacts of winter storms from 2001 - 2012 on coastal counties in the U.S. Northeast and underscores the significant economic consequences extreme winter storms have on property. The analysis on the types of hazards (floods, strong wind, snow, etc.) and associated damage from the National Climatic Data Center Storm Events Database indicates that floods were responsible for the highest damages. This finding suggests that winter storm vulnerability could grow in the future as precipitation intensity increases and sea level rise exacerbate flood losses. Flood loss maps are constructed based on damage amount, which can be compared to the flood exposure maps constructed by the NOAA Office of Coastal Management. Interesting agreements and discrepancies exist between the two methods, which warrant further examination. Furthermore, flood losses often came from storms characterized as heavy precipitation storms and strong surge storms, and sometimes both, illustrating the compounding effect of flood risks in the region. While New Jersey counties experienced the most damage per unit area, there is no discernable connection between population density and damage amount, which suggests that societal impacts may rely less on population characteristics and more on infrastructure types and property values, which vary throughout the region.

Impacts of Hurricane Rita on the beaches of western Louisiana: Chapter 5D in Science and the storms-the USGS response to the hurricanes of 2005

Science.gov (United States)

Stockdon, Hilary F.; Fauver, Laura A.; Sallenger,, Asbury H.; Wright, C. Wayne

2007-01-01

Hurricane Rita made landfall as a category 3 storm in western Louisiana in late September 2005, 1 month following Hurricane Katrina's devastating landfall in the eastern part of the State. Large waves and storm surge inundated the lowelevation coastline, destroying many communities and causing extensive coastal change including beach, dune, and marsh erosion.

A new deterministic Ensemble Kalman Filter with one-step-ahead smoothing for storm surge forecasting

KAUST Repository

Raboudi, Naila

2016-11-01

by performing assimilation experiments with the highly nonlinear Lorenz model and a realistic setting of the Advanced Circulation (ADCIRC) model configured for storm surge forecasting in the Gulf of Mexico during Hurricane Ike.

Surge-damping vacuum valve

International Nuclear Information System (INIS)

Bullock, J.C.; Kelley, B.E.

1977-01-01

A valve for damping out flow surges in a vacuum system is described. The surge-damping mechanism consists of a slotted, spring-loaded disk adjacent to the valve's vacuum port (the flow passage to the vacuum roughing pump). Under flow surge conditions, the differential pressure forces the disk into a sealing engagement with the vacuum port, thereby restricting the gas flow path to narrow slots in the disk's periphery. The increased flow damps out the flow surge. When pressure is equalized on both sides of the valve, the spring load moves the disk away from the port to restore full flow conductance through the valve

Prior storm experience moderates water surge perception and risk.

Directory of Open Access Journals (Sweden)

Gregory D Webster

Full Text Available BACKGROUND: How accurately do people perceive extreme water speeds and how does their perception affect perceived risk? Prior research has focused on the characteristics of moving water that can reduce human stability or balance. The current research presents the first experiment on people's perceptions of risk and moving water at different speeds and depths. METHODS: Using a randomized within-person 2 (water depth: 0.45, 0.90 m ×3 (water speed: 0.4, 0.8, 1.2 m/s experiment, we immersed 76 people in moving water and asked them to estimate water speed and the risk they felt. RESULTS: Multilevel modeling showed that people increasingly overestimated water speeds as actual water speeds increased or as water depth increased. Water speed perceptions mediated the direct positive relationship between actual water speeds and perceptions of risk; the faster the moving water, the greater the perceived risk. Participants' prior experience with rip currents and tropical cyclones moderated the strength of the actual-perceived water speed relationship; consequently, mediation was stronger for people who had experienced no rip currents or fewer storms. CONCLUSIONS: These findings provide a clearer understanding of water speed and risk perception, which may help communicate the risks associated with anticipated floods and tropical cyclones.

Health Effects of Coastal Storms and Flooding in Urban Areas: A Review and Vulnerability Assessment

Directory of Open Access Journals (Sweden)

Kathryn Lane

2013-01-01

Full Text Available Coastal storms can take a devastating toll on the public's health. Urban areas like New York City (NYC may be particularly at risk, given their dense population, reliance on transportation, energy infrastructure that is vulnerable to flood damage, and high-rise residential housing, which may be hard-hit by power and utility outages. Climate change will exacerbate these risks in the coming decades. Sea levels are rising due to global warming, which will intensify storm surge. These projections make preparing for the health impacts of storms even more important. We conducted a broad review of the health impacts of US coastal storms to inform climate adaptation planning efforts, with a focus on outcomes relevant to NYC and urban coastal areas, and incorporated some lessons learned from recent experience with Superstorm Sandy. Based on the literature, indicators of health vulnerability were selected and mapped within NYC neighborhoods. Preparing for the broad range of anticipated effects of coastal storms and floods may help reduce the public health burden from these events.

Health effects of coastal storms and flooding in urban areas: a review and vulnerability assessment.

Science.gov (United States)

Lane, Kathryn; Charles-Guzman, Kizzy; Wheeler, Katherine; Abid, Zaynah; Graber, Nathan; Matte, Thomas

2013-01-01

Coastal storms can take a devastating toll on the public's health. Urban areas like New York City (NYC) may be particularly at risk, given their dense population, reliance on transportation, energy infrastructure that is vulnerable to flood damage, and high-rise residential housing, which may be hard-hit by power and utility outages. Climate change will exacerbate these risks in the coming decades. Sea levels are rising due to global warming, which will intensify storm surge. These projections make preparing for the health impacts of storms even more important. We conducted a broad review of the health impacts of US coastal storms to inform climate adaptation planning efforts, with a focus on outcomes relevant to NYC and urban coastal areas, and incorporated some lessons learned from recent experience with Superstorm Sandy. Based on the literature, indicators of health vulnerability were selected and mapped within NYC neighborhoods. Preparing for the broad range of anticipated effects of coastal storms and floods may help reduce the public health burden from these events.

Factors controlling storm impacts on coastal barriers and beaches - A preliminary basis for near real-time forecasting

Science.gov (United States)

Morton, R.A.

2002-01-01

Analysis of ground conditions and meteorological and oceanographic parameters for some of the most severe Atlantic and Gulf Coast storms in the U.S. reveals the primary factors affecting morphological storm responses of beaches and barrier islands. The principal controlling factors are storm characteristics, geographic position relative to storm path, timing of storm events, duration of wave exposure, wind stress, degree of flow confinement, antecedent topography and geologic framework, sediment textures, vegetative cover, and type and density of coastal development. A classification of commonly observed storm responses demonstrates the sequential interrelations among (1) land elevations, (2) water elevations in the ocean and adjacent lagoon (if present), and (3) stages of rising water during the storm. The predictable coastal responses, in relative order from high frequency beach erosion to low frequency barrier inundation, include: beach erosion, berm migration, dune erosion, washover terrace construction, perched fan deposition, sheetwash, washover channel incision, washout formation, and forced and unforced ebb flow. Near real-time forecasting of expected storm impacts is possible if the following information is available for the coast: a detailed morphological and topographic characterization, accurate storm-surge and wave-runup models, the real-time reporting of storm parameters, accurate forecasts of the storm position relative to a particular coastal segment, and a conceptual model of geological processes that encompasses observed morphological changes caused by extreme storms.

Emergency department surge: models and practical implications.

Science.gov (United States)

Nager, Alan L; Khanna, Kajal

2009-08-01

Emergency Department crowding has long been described. Despite the daily challenges of managing emergency department volume and acuity; a surge response during a disaster entails even greater challenges including collaboration, intervention, and resourcefulness to effectively carry out pediatric disaster management. Understanding surge and how to respond with appropriate planning will lead to success. To achieve this, we sought to analyze models of surge; review regional and national data outlining surge challenges and factors that impact surge; and to outline potential solutions. We conducted a systemic review and included articles and documents that best described the theoretical and practical basis of surge response. We organized the systematic review according to the following questions: What are the elements and models that are delineated by the concept of surge? What is the basis for surge response based on regional and national published sources? What are the broad global solutions? What are the major lessons observed that will impact effective surge capacity? Multiple models of surge are described including public health, facility-based and community-based; a 6-tiered response system; and intrinsic or extrinsic surge capacity. In addition, essential components (4 S's of surge response) are described along with regional and national data outlining surge challenges, impacting factors, global solutions, and lesions observed. There are numerous shortcomings regionally and nationally affecting our ability to provide an effective and coordinated surge response. Planning, education, and training will lead to an effective pediatric disaster management response.

Decadal-scale variation in dune erosion and accretion rates: An investigation of the significance of changing storm tide frequency and magnitude on the Sefton coast, UK

Science.gov (United States)

Pye, K.; Blott, S. J.

2008-12-01

Monitoring of frontal dune erosion and accretion on the Sefton coast in northwest England over the past 50 years has revealed significant spatial and temporal variations. Previous work has shown that the spatial variations primarily reflect longshore differences in beach and nearshore morphology, energy regime and sediment budget, but the causes of temporal variations have not previously been studied in detail. This paper presents the results of work carried out to test the hypothesis that a major cause of temporal variation is changes in the frequency and magnitude of storms, surges and resulting high tides. Dune toe erosion/accretion records dating from 1958 have been compared with tide gauge records at Liverpool and Heysham. Relatively high dune erosion rates at Formby Point 1958-1968 were associated with a relatively large number of storm tides. Slower erosion at Formby, and relatively rapid accretion in areas to the north and south, occurred during the 1970's and 1980's when there were relatively few major storm tides. After 1990 rates of dune erosion at Formby increased again, and dunes to the north and south experienced slower accretion. During this period high storm tides have been more frequent, and the annual number of hours with water levels above the critical level for dune erosion has increased significantly. An increase in the rate of mean sea-level rise at both Liverpool and Heysham is evident since 1990, but we conclude that this factor is of less importance than the occurrence of extreme high tides and wave action associated with storms. The incidence of extreme high tides shows an identifiable relationship with the lunar nodal tidal cycle, but the evidence indicates that meteorological forcing has also had a significant effect. Storms and surges in the eastern Irish Sea are associated with Atlantic depressions whose direction and rate of movement have a strong influence on wind speeds, wave energy and the height of surge tides. However

Electrodynamics properties of auroral surges

International Nuclear Information System (INIS)

Robinson, R.M.; Vondrak, R.R.

1990-01-01

The incoherent scatter radar technique provides an excellent means to study the ionization and electric fields associated with auroral precipitation events. One of the most intense and dynamic auroral events is the so-called surge or breakup aurora that accompanies auroral substorms. For their purposes they define a surge as a transient intensification of auroral precipitation that occurs simultaneously with a pronounced negative bay in the ground magnetometer data. They present data obtained during five such events in 1980 and 1981. Prior to the surge, auroral forms move equatorward, develop ray structure, and intensify. The surge is identified by an apparent poleward motion of the aurora producing aurorally associated ionization that extends over several hundred kilometers in latitude. The presurge auroral forms are embedded in a region of northward electric field. The auroral forms that comprise the surge span a region within which the meridional electric field is small and at times southward. A westward electric field is often but not always present within the surge. The behavior of the westward electric field is significantly different from the north-south field, in that sharp spatial gradients are absent even in very disturbed conditions. Although the westward Hall currents are mostly responsible for the negative bays that accompany the surge, at times the westward Pedersen current sustained by the westward electric field can be important. Sudden variations in the H component of the ground magnetogram can be caused by motions of the aurora or by temporal variations in the fields or conductivities. They present a model that simulates the observed changes in electric field and precipitation that accompany surges. The perturbation in the electric field produced by the surge is simulated by adding negative potential in regions of intense precipitation

The Storm Surge and Sub-Grid Inundation Modeling in New York City during Hurricane Sandy

Directory of Open Access Journals (Sweden)

Harry V. Wang

2014-03-01

Full Text Available Hurricane Sandy inflicted heavy damage in New York City and the New Jersey coast as the second costliest storm in history. A large-scale, unstructured grid storm tide model, Semi-implicit Eulerian Lagrangian Finite Element (SELFE, was used to hindcast water level variation during Hurricane Sandy in the mid-Atlantic portion of the U.S. East Coast. The model was forced by eight tidal constituents at the model’s open boundary, 1500 km away from the coast, and the wind and pressure fields from atmospheric model Regional Atmospheric Modeling System (RAMS provided by Weatherflow Inc. The comparisons of the modeled storm tide with the NOAA gauge stations from Montauk, NY, Long Island Sound, encompassing New York Harbor, Atlantic City, NJ, to Duck, NC, were in good agreement, with an overall root mean square error and relative error in the order of 15–20 cm and 5%–7%, respectively. Furthermore, using large-scale model outputs as the boundary conditions, a separate sub-grid model that incorporates LIDAR data for the major portion of the New York City was also set up to investigate the detailed inundation process. The model results compared favorably with USGS’ Hurricane Sandy Mapper database in terms of its timing, local inundation area, and the depth of the flooding water. The street-level inundation with water bypassing the city building was created and the maximum extent of horizontal inundation was calculated, which was within 30 m of the data-derived estimate by USGS.

Design and quantification of an extreme winter storm scenario for emergency preparedness and planning exercises in California

Science.gov (United States)

Dettinger, M.D.; Martin, Ralph F.; Hughes, M.; Das, T.; Neiman, P.; Cox, D.; Estes, G.; Reynolds, D.; Hartman, R.; Cayan, D.; Jones, L.

2012-01-01

The USGS Multihazards Project is working with numerous agencies to evaluate and plan for hazards and damages that could be caused by extreme winter storms impacting California. Atmospheric and hydrological aspects of a hypothetical storm scenario have been quantified as a basis for estimation of human, infrastructure, economic, and environmental impacts for emergency-preparedness and flood-planning exercises. In order to ensure scientific defensibility and necessary levels of detail in the scenario description, selected historical storm episodes were concatentated to describe a rapid arrival of several major storms over the state, yielding precipitation totals and runoff rates beyond those occurring during the individual historical storms. This concatenation allowed the scenario designers to avoid arbitrary scalings and is based on historical occasions from the 19th and 20th Centuries when storms have stalled over the state and when extreme storms have arrived in rapid succession. Dynamically consistent, hourly precipitation, temperatures, barometric pressures (for consideration of storm surges and coastal erosion), and winds over California were developed for the so-called ARkStorm scenario by downscaling the concatenated global records of the historical storm sequences onto 6- and 2-km grids using a regional weather model of January 1969 and February 1986 storm conditions. The weather model outputs were then used to force a hydrologic model to simulate ARkStorm runoff, to better understand resulting flooding risks. Methods used to build this scenario can be applied to other emergency, nonemergency and non-California applications. ?? 2011 The Author(s).

Wetland shoreline recession in the Mississippi River Delta from petroleum oiling and cyclonic storms

Science.gov (United States)

Rangoonwala, Amina; Jones, Cathleen E.; Ramsey, Elijah W.

2016-01-01

We evaluate the relative impact of petroleum spill and storm surge on near-shore wetland loss by quantifying the lateral movement of coastal shores in upper Barataria Bay, Louisiana (USA), between June 2009 and October 2012, a study period that extends from the year prior to the Deepwater Horizon spill to 2.5 years following the spill. We document a distinctly different pattern of shoreline loss in the 2 years following the spill, both from that observed in the year prior to the spill, during which there was no major cyclonic storm, and from change related to Hurricane Isaac, which made landfall in August 2012. Shoreline erosion following oiling was far more spatially extensive and included loss in areas protected from wave-induced erosion. We conclude that petroleum exposure can substantially increase shoreline recession particularly in areas protected from storm-induced degradation and disproportionally alters small oil-exposed barrier islands relative to natural erosion.

Sele coastal plain flood risk due to wave storm and river flow interaction

Science.gov (United States)

Benassai, Guido; Aucelli, Pietro; Di Paola, Gianluigi; Della Morte, Renata; Cozzolino, Luca; Rizzo, Angela

2016-04-01

Wind waves, elevated water levels and river discharge can cause flooding in low-lying coastal areas, where the water level is the interaction between wave storm elevated water levels and river flow interaction. The factors driving the potential flood risk include weather conditions, river water stage and storm surge. These data are required to obtain inputs to run the hydrological model used to evaluate the water surface level during ordinary and extreme events regarding both the fluvial overflow and storm surge at the river mouth. In this paper we studied the interaction between the sea level variation and the river hydraulics in order to assess the location of the river floods in the Sele coastal plain. The wave data were acquired from the wave buoy of Ponza, while the water level data needed to assess the sea level variation were recorded by the tide gauge of Salerno. The water stages, river discharges and rating curves for Sele river were provided by Italian Hydrographic Service (Servizio Idrografico e Mareografico Nazionale, SIMN).We used the dataset of Albanella station (40°29'34.30"N, 15°00'44.30"E), located around 7 km from the river mouth. The extreme river discharges were evaluated through the Weibull equation, which were associated with their return period (TR). The steady state river water levels were evaluated through HEC-RAS 4.0 model, developed by Hydrologic Engineering Center (HEC) of the United States Army Corps of Engineers Hydrologic Engineering Center (USACE,2006). It is a well-known 1D model that computes water surface elevation (WSE) and velocity at discrete cross-sections by solving continuity, energy and flow resistance (e.g., Manning) equation. Data requirements for HEC-RAS include topographic information in the form of a series of cross-sections, friction parameter in the form of Manning's n values across each cross-section, and flow data including flow rates, flow change locations, and boundary conditions. For a steady state sub

On the use of wave parameterizations and a storm impact scaling model in National Weather Service Coastal Flood and decision support operations

Science.gov (United States)

Mignone, Anthony; Stockdon, H.; Willis, M.; Cannon, J.W.; Thompson, R.

2012-01-01

National Weather Service (NWS) Weather Forecast Offices (WFO) are responsible for issuing coastal flood watches, warnings, advisories, and local statements to alert decision makers and the general public when rising water levels may lead to coastal impacts such as inundation, erosion, and wave battery. Both extratropical and tropical cyclones can generate the prerequisite rise in water level to set the stage for a coastal impact event. Forecasters use a variety of tools including computer model guidance and local studies to help predict the potential severity of coastal flooding. However, a key missing component has been the incorporation of the effects of waves in the prediction of total water level and the associated coastal impacts. Several recent studies have demonstrated the importance of incorporating wave action into the NWS coastal flood program. To follow up on these studies, this paper looks at the potential of applying recently developed empirical parameterizations of wave setup, swash, and runup to the NWS forecast process. Additionally, the wave parameterizations are incorporated into a storm impact scaling model that compares extreme water levels to beach elevation data to determine the mode of coastal change at predetermined “hotspots” of interest. Specifically, the storm impact model compares the approximate storm-induced still water level, which includes contributions from tides, storm surge, and wave setup, to dune crest elevation to determine inundation potential. The model also compares the combined effects of tides, storm surge, and the 2 % exceedance level for vertical wave runup (including both wave setup and swash) to dune toe and crest elevations to determine if erosion and/or ocean overwash may occur. The wave parameterizations and storm impact model are applied to two cases in 2009 that led to significant coastal impacts and unique forecast challenges in North Carolina: the extratropical “Nor'Ida” event during 11-14 November and

Impact of storms on coastlines: preparing for the future without forgetting the past? Examples from European coastlines using a Storm Impact Database

Science.gov (United States)

Ciavola, Paolo; Garnier, Emmanuel; Ferreira, Oscar; Spencer, Thomas; Armaroli, Clara

2017-04-01

Severe storms have historically affected many European coastlines but the impact of each storm has been evaluated in different ways in different countries, often using local socio-economic impact criteria (e.g. loss of lives and damage to properties). Although the Xynthia (2010) storm, Atlantic coast of France, was the largest coastal disaster of the last 50 years, similar events have previously impacted Europe. The 1953 storm surge in the southern North Sea, resulted in over 2000 deaths and extensive flooding and was the catalyst for post WWII improvements in flood defences and storm early warning systems. On a longer timescale, the very extreme storm of 1634 AD re-configured Wadden Sea coastlines, accompanied by thousands of deaths. Establishing patterns of coastal risk and vulnerability is greatly helped by the use of historical sources, as these allow the development of more complete time series of storm events and their impacts. The work to be presented was supported by the EU RISC-KIT (Resilience-Increasing Strategies for Coasts - toolKIT) Project. RISC-KIT (http://www.risckit.eu/np4/home.html) is a EU FP7 Collaborative project that has developed methods, tools and management approaches to reduce risk and increase resilience to low frequency, high-impact hydro-meteorological events in the coastal zone. These products will enhance forecasting, prediction and early warning capabilities, improve the assessment of long-term coastal risk and optimize the mix of prevention, mitigation and preparedness measures. We analyse historical large-scale events occurred from The Middle Ages to the 1960s at the case study sites of North Norfolk Coast (UK), the Charente-Maritime and Vendée coast (France), the Cinque Terre-Liguria (Italy), the Emilia-Romagna coast (Italy), and the Ria Formosa coast (Portugal). The work presented here uses a database of events built by the project, examining records for the last 300 years, including the characteristics of the storms as well as

Meteorological and oceanographic aspects of a winter storm over the south-western Cape Province, South Africa

International Nuclear Information System (INIS)

Jury, M.R.; Shillington, F.A.; Prestidge, G.; Maxwell, C.D.

1986-01-01

In May the southern hemisphere circumpolar jet stream accelerates in response to a growing temperature gradient between the pole and equator. Initially, the jet stream may 'spin up' in pulses, causing the upper air current to become unstable and to meander equatorwards out of the higher latitudes (40-50 degrees S). Winter storms induced by the jet stream and which move, from west to east, to the south of the African continent are then guided by the upper air currents further north. Between 15 and 17 May 1984, such a sequence of synoptic weather events developed and the south-western Cape came under the influence of the 'roaring 40's'. In this article a chronology of the storm and its meteorological effects are described using data collected at the Koeberg nuclear power station, the Cape Town Airport Weather Office and across the south-western Cape. The destructive effects of the storm, particularly felt along the coast as a result of large swells and a significant storm surge, are discussed

Coastal Flooding in Florida's Big Bend Region with Application to Sea Level Rise Based on Synthetic Storms Analysis

Directory of Open Access Journals (Sweden)

Scott C. Hagen Peter Bacopoulos

2012-01-01

Full Text Available Flooding is examined by comparing maximum envelopes of water against the 0.2% (= 1-in-500-year return-period flooding surface generated as part of revising the Federal Emergency Management Agency¡¦s flood insurance rate maps for Franklin, Wakulla, and Jefferson counties in Florida¡¦s Big Bend Region. The analysis condenses the number of storms to a small fraction of the original 159 used in production. The analysis is performed by assessing which synthetic storms contributed to inundation extent (the extent of inundation into the floodplain, coverage (the overall surface area of the inundated floodplain and the spatially variable 0.2% flooding surface. The results are interpreted in terms of storm attributes (pressure deficit, radius to maximum winds, translation speed, storm heading, and landfall location and the physical processes occurring within the natural system (storms surge and waves; both are contextualized against existing and new hurricane scales. The approach identifies what types of storms and storm attributes lead to what types of inundation, as measured in terms of extent and coverage, in Florida¡¦s Big Bend Region and provides a basis in the identification of a select subset of synthetic storms for studying the impact of sea level rise. The sea level rise application provides a clear contrast between a dynamic approach versus that of a static approach.

Sea, Lake, and Overland Surge from Hurricanes (SLOSH) Inundation for Categories 2 and 4

Science.gov (United States)

The file geodatabase (fgdb) contains the Sea, Lake, and Overland Surge from Hurricanes (SLOSH) Maximum of Maximums (MOM) model for hurricane categories 2 and 4. The EPA Office of Research & Development (ORD) modified the original model from NOAA to fit the model parameters for the Buzzards Bay region. The models show storm surge extent for the Mattapoisett area and therefore the flooding area was reduced to the study area. Areas of flooding that were not connected to the main water body were removed. The files in the geodatabase are:Cat2_SLR0_Int_Feet_dissolve_Mattapoisett: Current Category 2 hurricane with 0 ft sea level riseCat4_SLR0_Int_Feet_dissolve_Mattapoisett: Current Category 4 hurricane with 0 ft sea level riseCat4_SLR4_Int_Feet_dissolve_Mattapoisett: Future Category 4 hurricane with 4 feet sea level riseThe features support the Weather Ready Mattapoisett story map, which can be accessed via the following link:https://epa.maps.arcgis.com/apps/MapJournal/index.html?appid=1ff4f1d28a254cb689334799d94b74e2

Impacts of storm chronology on the morphological changes of the Formby beach and dune system, UK

Science.gov (United States)

Dissanayake, P.; Brown, J.; Karunarathna, H.

2015-07-01

Impacts of storm chronology within a storm cluster on beach/dune erosion are investigated by applying the state-of-the-art numerical model XBeach to the Sefton coast, northwest England. Six temporal storm clusters of different storm chronologies were formulated using three storms observed during the 2013/2014 winter. The storm power values of these three events nearly halve from the first to second event and from the second to third event. Cross-shore profile evolution was simulated in response to the tide, surge and wave forcing during these storms. The model was first calibrated against the available post-storm survey profiles. Cumulative impacts of beach/dune erosion during each storm cluster were simulated by using the post-storm profile of an event as the pre-storm profile for each subsequent event. For the largest event the water levels caused noticeable retreat of the dune toe due to the high water elevation. For the other events the greatest evolution occurs over the bar formations (erosion) and within the corresponding troughs (deposition) of the upper-beach profile. The sequence of events impacting the size of this ridge-runnel feature is important as it consequently changes the resilience of the system to the most extreme event that causes dune retreat. The highest erosion during each single storm event was always observed when that storm initialised the storm cluster. The most severe storm always resulted in the most erosion during each cluster, no matter when it occurred within the chronology, although the erosion volume due to this storm was reduced when it was not the primary event. The greatest cumulative cluster erosion occurred with increasing storm severity; however, the variability in cumulative cluster impact over a beach/dune cross section due to storm chronology is minimal. Initial storm impact can act to enhance or reduce the system resilience to subsequent impact, but overall the cumulative impact is controlled by the magnitude and number

Hurricane impacts on coastal wetlands: a half-century record of storm-generated features from southern Louisiana

Science.gov (United States)

Morton, Robert A.; Barras, John A.

2011-01-01

Temporally and spatially repeated patterns of wetland erosion, deformation, and deposition are observed on remotely sensed images and in the field after hurricanes cross the coast of Louisiana. The diagnostic morphological wetland features are products of the coupling of high-velocity wind and storm-surge water and their interaction with the underlying, variably resistant, wetland vegetation and soils. Erosional signatures include construction of orthogonal-elongate ponds and amorphous ponds, pond expansion, plucked marsh, marsh denudation, and shoreline erosion. Post-storm gravity reflux of floodwater draining from the wetlands forms dendritic incisions around the pond margins and locally integrates drainage pathways forming braided channels. Depositional signatures include emplacement of broad zones of organic wrack on topographic highs and inorganic deposits of variable thicknesses and lateral extents in the form of shore-parallel sandy washover terraces and interior-marsh mud blankets. Deformational signatures primarily involve laterally compressed marsh and displaced marsh mats and balls. Prolonged water impoundment and marsh salinization also are common impacts associated with wetland flooding by extreme storms. Many of the wetland features become legacies that record prior storm impacts and locally influence subsequent storm-induced morphological changes. Wetland losses caused by hurricane impacts depend directly on impact duration, which is controlled by the diameter of hurricane-force winds, forward speed of the storm, and wetland distance over which the storm passes. Distinguishing between wetland losses caused by storm impacts and losses associated with long-term delta-plain processes is critical for accurate modeling and prediction of future conversion of land to open water.

Surge of a Complex Glacier System - The Current Surge of the Bering-Bagley Glacier System, Alaska

Science.gov (United States)

Herzfeld, U. C.; McDonald, B.; Trantow, T.; Hale, G.; Stachura, M.; Weltman, A.; Sears, T.

2013-12-01

Understanding fast glacier flow and glacial accelerations is important for understanding changes in the cryosphere and ultimately in sea level. Surge-type glaciers are one of four types of fast-flowing glaciers --- the other three being continuously fast-flowing glaciers, fjord glaciers and ice streams --- and the one that has seen the least amount of research. The Bering-Bagley Glacier System, Alaska, the largest glacier system in North America, surged in 2011 and 2012. Velocities decreased towards the end of 2011, while the surge kinematics continued to expand. A new surge phase started in summer and fall 2012. In this paper, we report results from airborne observations collected in September 2011, June/July and September/October 2012 and in 2013. Airborne observations include simultaneously collected laser altimeter data, videographic data, GPS data and photographic data and are complemented by satellite data analysis. Methods range from classic interpretation of imagery to analysis and classification of laser altimeter data and connectionist (neural-net) geostatistical classification of concurrent airborne imagery. Results focus on the characteristics of surge progression in a large and complex glacier system (as opposed to a small glacier with relatively simple geometry). We evaluate changes in surface elevations including mass transfer and sudden drawdowns, crevasse types, accelerations and changes in the supra-glacial and englacial hydrologic system. Supraglacial water in Bering Glacier during Surge, July 2012 Airborne laser altimeter profile across major rift in central Bering Glacier, Sept 2011

A numerical study of wave-current interaction through surface and bottom stresses: Coastal ocean response to Hurricane Fran of 1996

Science.gov (United States)

Xie, L.; Pietrafesa, L. J.; Wu, K.

2003-02-01

A three-dimensional wave-current coupled modeling system is used to examine the influence of waves on coastal currents and sea level. This coupled modeling system consists of the wave model-WAM (Cycle 4) and the Princeton Ocean Model (POM). The results from this study show that it is important to incorporate surface wave effects into coastal storm surge and circulation models. Specifically, we find that (1) storm surge models without coupled surface waves generally under estimate not only the peak surge but also the coastal water level drop which can also cause substantial impact on the coastal environment, (2) introducing wave-induced surface stress effect into storm surge models can significantly improve storm surge prediction, (3) incorporating wave-induced bottom stress into the coupled wave-current model further improves storm surge prediction, and (4) calibration of the wave module according to minimum error in significant wave height does not necessarily result in an optimum wave module in a wave-current coupled system for current and storm surge prediction.

48 CFR 252.217-7001 - Surge option.

Science.gov (United States)

2010-10-01

... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Surge option. 252.217-7001... Clauses 252.217-7001 Surge option. As prescribed in 217.208-70(b), use the following clause: Surge Option (AUG 1992) (a) General. The Government has the option to— (1) Increase the quantity of supplies or...

Assessing storm events for energy meteorology: using media and scientific reports to track a North Sea autumn storm.

Science.gov (United States)

Kettle, Anthony

2016-04-01

Important issues for energy meteorology are to assess meteorological conditions for normal operating conditions and extreme events for the ultimate limit state of engineering structures. For the offshore environment in northwest Europe, energy meteorology encompasses weather conditions relevant for petroleum production infrastructure and also the new field of offshore wind energy production. Autumn and winter storms are an important issue for offshore operations in the North Sea. The weather in this region is considered as challenging for extreme meteorological events as the Gulf of Mexico with its attendant hurricane risk. The rise of the Internet and proliferation of digital recording devices has placed a much greater amount of information in the public domain than was available to national meteorological agencies even 20 years ago. This contribution looks at reports of meteorology and infrastructure damage from a storm in the autumn of 2006 to trace the spatial and temporal record of meteorological events. Media reports give key information to assess the events of the storm. The storm passed over northern Europe between Oct.31-Nov. 2, 2006, and press reports from the time indicate that its most important feature was a high surge that inundated coastal areas. Sections of the Dutch and German North Sea coast were affected, and there was record flooding in Denmark and East Germany in the southern Baltic Sea. Extreme wind gusts were also reported that were strong enough to damage roofs and trees, and there was even tornado recorded near the Dutch-German border. Offshore, there were a series of damage reports from ship and platforms that were linked with sea state, and reports of rogue waves were explicitly mentioned. Many regional government authorities published summaries of geophysical information related to the storm, and these form part of a regular series of online winter storm reports that started as a public service about 15 years ago. Depending on the

Effect of piping systems on surge in centrifugal compressors

International Nuclear Information System (INIS)

Tamaki, Hideaki

2008-01-01

There is a possibility that the exchange of the piping system may change the surge characteristic of a compressor. The piping system of a plant is not always the same as that of a test site. Then it is important to evaluate the effect of piping systems on surge characteristics in centrifugal compressors. Several turbochargers combined with different piping systems were tested. The lumped parameter model which was simplified to be solved easily was applied for the prediction of surge point. Surge lines were calculated with the linearlized lumped parameter model. The difference between the test and calculated results was within 10 %. Trajectory of surge cycle was also examined by solving the lumped parameter model. Mild surge and deep surge were successfully predicted. This study confirmed that the lumped parameter model was a very useful tool to predict the effect of piping systems on surge characteristics in centrifugal compressors, even though that was a simple model

Storms

International Nuclear Information System (INIS)

Kai, Keizo; Melrose, D.B.; Suzuki, S.

1985-01-01

At metre and decametre wavelengths long-lasting solar radio emission, consisting of thousands of short-lived spikes superimposed on a slowly varying continuum, is observed. This type of storm emission may continue for periods ranging from a few hours to several days; the long duration is one of the characteristics which distinguish storms from other types of solar radio emission. These events are called storms or noise storms by analogy with geomagnetic storms. (author)

Validation of a surge model by full scale testing

NARCIS (Netherlands)

Smeulers, J.P.M.; Slot, H.J.; Meulendijks, D.

2011-01-01

Surge of turbo compressors can cause large stepwise changes in flow and pressure, which can potentially damage the compressor and any equipment that is in direct connection with the compressor. Surge is usually avoided by an anti surge controller (ASC). However, in spite of the ASC surge cycles may

Validation of a surge model by full scale testing

NARCIS (Netherlands)

Slot, H.J.; Meulendijks, D.; Smeulers, J.P.M.

2009-01-01

Surge of turbo compressors can cause large stepwise changes in flow and pressure, which can potentially damage the compressor and any equipment that is in direct connection with the compressor. Surge is usually avoided by an anti surge controller (ASC). However, in spite of the ASC surge cycles may

Observations and predictions of wave runup, extreme water levels, and medium-term dune erosion during storm conditions

OpenAIRE

Suanez , Serge ,; Cancouët , Romain; Floc'h , France; Blaise , Emmanuel; Ardhuin , Fabrice; Filipot , Jean-François; Cariolet , Jean-Marie; Delacourt , Christophe

2015-01-01

Monitoring of dune erosion and accretion on the high-energy macrotidal Vougot beach in North Brittany (France) over the past decade (2004–2014) has revealed significant morphological changes. Dune toe erosion/accretion records have been compared with extreme water level measurements, defined as the sum of (i) astronomic tide; (ii) storm surge; and (iii) vertical wave runup. Runup parameterization was conducted using swash limits, beach profiles, and hydrodynamic (Hm0, Tm0,–1, and high tide wa...

Designsafe-Ci a Cyberinfrastructure for Natural Hazard Simulation and Data

Science.gov (United States)

Dawson, C.; Rathje, E.; Stanzione, D.; Padgett, J.; Pinelli, J. P.

2017-12-01

DesignSafe is the web-based research platform of the Natural Hazards Engineering Research Infrastructure (NHERI) network that provides the computational tools needed to manage and analyze critical data for natural hazards research, with wind and storm surge related hazards being a primary focus. One of the simulation tools under DesignSafe is the Advanced Circulation (ADCIRC) model, a coastal ocean model used in storm surge analysis. ADCIRC is an unstructured, finite element model with high resolution capabilities for studying storm surge impacts, and has long been used in storm surge hind-casting and forecasting. In this talk, we will demonstrate the use of ADCIRC within the DesignSafe platform and its use for forecasting Hurricane Harvey. We will also demonstrate how to analyze, visualize and archive critical storm surge related data within DesignSafe.

The exposure of Sydney (Australia) to earthquake-generated tsunamis, storms and sea level rise: a probabilistic multi-hazard approach.

Science.gov (United States)

Dall'Osso, F; Dominey-Howes, D; Moore, C; Summerhayes, S; Withycombe, G

2014-12-10

Approximately 85% of Australia's population live along the coastal fringe, an area with high exposure to extreme inundations such as tsunamis. However, to date, no Probabilistic Tsunami Hazard Assessments (PTHA) that include inundation have been published for Australia. This limits the development of appropriate risk reduction measures by decision and policy makers. We describe our PTHA undertaken for the Sydney metropolitan area. Using the NOAA NCTR model MOST (Method for Splitting Tsunamis), we simulate 36 earthquake-generated tsunamis with annual probabilities of 1:100, 1:1,000 and 1:10,000, occurring under present and future predicted sea level conditions. For each tsunami scenario we generate a high-resolution inundation map of the maximum water level and flow velocity, and we calculate the exposure of buildings and critical infrastructure. Results indicate that exposure to earthquake-generated tsunamis is relatively low for present events, but increases significantly with higher sea level conditions. The probabilistic approach allowed us to undertake a comparison with an existing storm surge hazard assessment. Interestingly, the exposure to all the simulated tsunamis is significantly lower than that for the 1:100 storm surge scenarios, under the same initial sea level conditions. The results have significant implications for multi-risk and emergency management in Sydney.

Building Coastal Resilience to sea-level rise and storm hazards: supporting decisions in the NE USA, Gulf of Mexico, and eastern Caribbean

Science.gov (United States)

Shepard, C.; Beck, M. W.; Gilmer, B.; Ferdana, Z.; Raber, G.; Agostini, V.; Whelchel, A.; Stone, J.

2012-12-01

Coastal communities are increasingly vulnerable to coastal hazards including storm surge and sea level rise. We describe the use of Coastal Resilience, an approach to help support decisions to reduce socio-economic and ecological vulnerability to coastal hazards. We provide examples of this work from towns and cities around Long Island Sound (NY, CT) and the Gulf of Mexico (FL, AL, MS, LA, TX) in the USA and from the Eastern Caribbean (Grenada, St. Vincent and the Grenadines). All of these shores are densely populated and have significant coastal development only centimetres above the sea. This makes people and property very vulnerable and threatens coastal wetlands (marsh, mangrove) and reefs (oyster, coral) that provide habitat and natural buffers to storms while providing other ecosystem services. We describe this work specifically and then offer broader perspectives and recommendations for using ecological habitats to reduce vulnerability to coastal hazards. The Nature Conservancy's Coastal Resilience approach is driven by extensive community engagement and uses spatial information on storm surge, sea level rise, ecological and socio-economic variables to identify options for reducing the vulnerability of human and natural communities to coastal hazards (http://www.coastalresilience.org). We have worked with local communities to map current and future coastal hazards and to identify the vulnerable natural resources and human communities. Communities are able to visualize potential hazard impacts and identify options to reduce them within their existing planning and regulatory frameworks.

Surge Protection in Low-Voltage AC Power Circuits: An Anthology

Science.gov (United States)

Martzloff, F. D.

2002-10-01

The papers included in this part of the Anthology provide basic information on the propagation of surges in low-voltage AC power circuits. The subject was approached by a combination of experiments and theoretical considerations. One important distinction is made between voltage surges and current surges. Historically, voltage surges were the initial concern. After the introduction and widespread use of current-diverting surge-protective devices at the point-of-use, the propagation of current surges became a significant factor. The papers included in this part reflect this dual dichotomy of voltage versus current and impedance mismatch effects versus simple circuit theory.

The use of long-term observations in combination with modeling and their effect on the estimation of the North Sea storm surge climate

Energy Technology Data Exchange (ETDEWEB)

Aspelien, T.

2006-07-01

The aim of this PhD thesis is to design, implement and assess a method to combine long-term observations with multi-decadal model simulations. In this work a computationally cost-efficient nudging method, well suited for multi-decadal simulations, is chosen. First, the nudging method was tested for its sensitivity to different parameters. Then the long-term observations of sea level height from the UK tide gauge Aberdeen were combined with a multi-decadal hindcast for the North Sea. Compared to a control simulation, in which no observed values of sea level height were combined with the model, the nudging method generally improves the modeled water levels with respect to the observed values, especially for surge. The estimation of long-term fluctuations and biases of extreme values of high waters in the nudged simulation are generally considerably improved after nudging and closer to the observed. The effect is largest in the German Bight and at the West coast of Denmark. It is concluded that the cost-efficient nudging method, in which external processes, such as external surges, are additionally taken into account, provides a considerable improvement in reproducing long-term variations and trends, especially for surge. Without additional data from e.g. observed values from tide gauges taken into account, the meteorological induced long-term variations in a hindcast are not fully captured. (orig.)

Exceptional winter storms affecting Western Iberia and extremes: diagnosis, modelling and multi-model ensemble projection

Science.gov (United States)

Liberato, M. L. R.; Pinto, J. G.; Gil, V.; Ramos, A. M.; Trigo, R. M.

2017-12-01

Extratropical cyclones dominate autumn and winter weather over Western Europe and particularly over the Iberian Peninsula. Intense, high-impact storms are one of the major weather risks in the region, mostly due to the simultaneous occurrence of high winds and extreme precipitation events. These intense extratropical cyclones may result in windstorm damage, flooding and coastal storm surges, with large societal impacts. In Portugal, due to the extensive human use of coastal areas, the natural and built coastal environments have been amongst the most affected. In this work several historical winter storms that adversely affected the Western Iberian Peninsula are studied in detail in order to contribute to an improved assessment of the characteristics of these events. The diagnosis has been performed based on instrumental daily precipitation and wind records, on satellite images, on reanalysis data and through model simulations. For several examples the synoptic evolution and upper-level dynamics analysis of physical processes controlling the life cycle of extratropical storms associated with the triggering of the considered extreme events has also been accomplished. Furthermore, the space-time variability of the exceptionally severe storms affecting Western Iberia over the last century and under three climate scenarios (the historical simulation, the RCP4.5 and RCP8.5 scenarios) is presented. These studies contribute to improving the knowledge of atmospheric dynamics controlling the life cycle of midlatitude storms associated to severe weather (precipitation and wind) in the Iberian Peninsula. AcknowledgementsThis work is supported by the Portuguese Foundation for Science and Technology (FCT), Portugal, through project UID/GEO/50019/2013 - Instituto Dom Luiz. A. M. Ramos is also supported by a FCT postdoctoral grant (FCT/DFRH/SFRH/BPD/84328/2012).

Volume-based characterization of postocclusion surge.

Science.gov (United States)

Zacharias, Jaime; Zacharias, Sergio

2005-10-01

To propose an alternative method to characterize postocclusion surge using a collapsible artificial anterior chamber to replace the currently used rigid anterior chamber model. Fundación Oftamológica Los Andes, Santiago, Chile. The distal end of a phacoemulsification handpiece was placed inside a compliant artificial anterior chamber. Digital recordings of chamber pressure, chamber volume, inflow, and outflow were performed during occlusion break of the phacoemulsification tip. The occlusion break profile of 2 different consoles was compared. Occlusion break while using a rigid anterior chamber model produced a simultaneous increase of chamber inflow and outflow. In the rigid chamber model, pressure decreased sharply, reaching negative pressure values. Alternatively, with the collapsible chamber model, a delay was observed in the inflow that occurs to compensate the outflow surge. Also, the chamber pressure drop was smaller in magnitude, never undershooting below atmospheric pressure into negative values. Using 500 mm Hg as vacuum limit, the Infiniti System (Alcon) performed better that the Legacy (Alcon), showing an 18% reduction in peak volume variation. The collapsible anterior chamber model provides a more realistic representation of the postocclusion surge events that occur in the real eye during cataract surgery. Peak volume fluctuation (mL), half volume recovery time(s), and volume fluctuation integral value (mL x s) are proposed as realistic indicators to characterize the postocclusion surge performance. These indicators show that the Infiniti System has a better postocclusion surge behavior than the Legacy System.

Hazard Assessment from Storm Tides and Rainfall on a Tidal River Estuary

Science.gov (United States)

Orton, P.; Conticello, F.; Cioffi, F.; Hall, T.; Georgas, N.; Lall, U.; Blumberg, A.

2015-01-01

Here, we report on methods and results for a model-based flood hazard assessment we have conducted for the Hudson River from New York City to Troy/Albany at the head of tide. Our recent work showed that neglecting freshwater flows leads to underestimation of peak water levels at up-river sites and neglecting stratification (typical with two-dimensional modeling) leads to underestimation all along the Hudson. As a result, we use a three-dimensional hydrodynamic model and merge streamflows and storm tides from tropical and extratropical cyclones (TCs, ETCs), as well as wet extratropical cyclone (WETC) floods (e.g. freshets, rain-on-snow events). We validate the modeled flood levels and quantify error with comparisons to 76 historical events. A Bayesian statistical method is developed for tropical cyclone streamflows using historical data and consisting in the evaluation of (1) the peak discharge and its pdf as a function of TC characteristics, and (2) the temporal trend of the hydrograph as a function of temporal evolution of the cyclone track, its intensity and the response characteristics of the specific basin. A k-nearest-neighbors method is employed to determine the hydrograph shape. Out of sample validation tests demonstrate the effectiveness of the method. Thus, the combined effects of storm surge and runoff produced by tropical cyclones hitting the New York area can be included in flood hazard assessment. Results for the upper Hudson (Albany) suggest a dominance of WETCs, for the lower Hudson (at New York Harbor) a case where ETCs are dominant for shorter return periods and TCs are more important for longer return periods (over 150 years), and for the middle-Hudson (Poughkeepsie) a mix of all three flood events types is important. However, a possible low-bias for TC flood levels is inferred from a lower importance in the assessment results, versus historical event top-20 lists, and this will be further evaluated as these preliminary methods and results are

Surge flow irrigation under short field conditions in Egypt

NARCIS (Netherlands)

Ismail, S.M.; Depeweg, H.; Schultz, E.

2004-01-01

Several studies carried out in long furrows have shown that surge flow irrigation offers the potential of increasing the efficiency of irrigation. The effects of surge flow in short fields, such as in Egypt, are still not well known, however. To investigate the effect of surge flow irrigation in

Validation of a surge model by full scale testing

NARCIS (Netherlands)

Smeulers, J.P.M.; Gonzalez Díez, N.; Slot, H.J.

2012-01-01

Surge of turbo compressors can cause large almost step like changes in flow and pressure, which can potentially damage the compressor and any equipment that is in direct connection with the compressor. In spite of an anti-surge controller (ASC), at extreme events surge cycles may occur. In order to

Marine Text Forecasts and Products Listing

Science.gov (United States)

FQPZ23KWNO West Coast 06z, 18z FQAC23KWNO Artic Alaska 06z, 18z Computer-generated extratropical storm surge Water Levels Tsunami Coastal/Lakeshore Hazard Message; Storm Surge Forecasts Satellite Orbit Predictions Update (Storm #1) As required TCUAT2 (alt) Tropical Cyclone Update (Storm #2) As required TCUAT3 (alt

Coastal flooding hazard related to storms and coastal evolution in Valdelagrana spit (Cadiz Bay Natural Park, SW Spain)

Science.gov (United States)

Benavente, J.; Del Río, L.; Gracia, F. J.; Martínez-del-Pozo, J. A.

2006-06-01

Mapping of coastal inundation hazard related to storms requires the combination of multiple sources of information regarding meteorological, morphological and dynamic characteristics of both the area at risk and the studied phenomena. Variables such as beach slope, storm wave height or wind speed have traditionally been used, but detailed geomorphological features of the area as well as long-term shoreline evolution trends must also be taken into account in order to achieve more realistic results. This work presents an evaluation of storm flooding hazard in Valdelagrana spit and marshes (SW Spain), considering two types of storm that are characteristic of the area: a modal storm with 1 year of recurrence interval (maximum wave height of 3.3 m), and an extreme storm with 6-10 years of recurrence interval (maximum wave height of 10.6 m), both approaching the coast perpendicularly. After calculating theoretical storm surge elevation, a digital terrain model was made by adjusting topographic data to field work and detailed geomorphological analysis. A model of flooding extent was subsequently developed for each storm type, and then corrected according to the rates of shoreline change in the last decades, which were assessed by means of aerial photographs taking the dune toe as shoreline indicator. Results show that long-term coastline trend represents an important factor in the prediction of flooding extent, since shoreline retreat causes the deterioration of natural coastal defences as dune ridges, thus increasing coastal exposure to high-energy waves. This way, it has been stated that the lack of sedimentary supply plays an important role in spatial variability of inundation extent in Valdelagrana spit. Finally, a hazard map is presented, where calculated coastal retreat rates are employed in order to predict the areas that could be affected by future inundation events.

Monitoring storm tide and flooding from Hurricane Matthew along the Atlantic coast of the United States, October 2016

Science.gov (United States)

Frantz, Eric R.; Byrne,, Michael L.; Caldwell, Andral W.; Harden, Stephen L.

2017-11-02

IntroductionHurricane Matthew moved adjacent to the coasts of Florida, Georgia, South Carolina, and North Carolina. The hurricane made landfall once near McClellanville, South Carolina, on October 8, 2016, as a Category 1 hurricane on the Saffir-Simpson Hurricane Wind Scale. The U.S. Geological Survey (USGS) deployed a temporary monitoring network of storm-tide sensors at 284 sites along the Atlantic coast from Florida to North Carolina to record the timing, areal extent, and magnitude of hurricane storm tide and coastal flooding generated by Hurricane Matthew. Storm tide, as defined by the National Oceanic and Atmospheric Administration, is the water-level rise generated by a combination of storm surge and astronomical tide during a coastal storm.The deployment for Hurricane Matthew was the largest deployment of storm-tide sensors in USGS history and was completed as part of a coordinated Federal emergency response as outlined by the Stafford Act (Public Law 92–288, 42 U.S.C. 5121–5207) under a directed mission assignment by the Federal Emergency Management Agency. In total, 543 high-water marks (HWMs) also were collected after Hurricane Matthew, and this was the second largest HWM recovery effort in USGS history after Hurricane Sandy in 2012.During the hurricane, real-time water-level data collected at temporary rapid deployment gages (RDGs) and long-term USGS streamgage stations were relayed immediately for display on the USGS Flood Event Viewer (https://stn.wim.usgs.gov/FEV/#MatthewOctober2016). These data provided emergency managers and responders with critical information for tracking flood-effected areas and directing assistance to effected communities. Data collected from this hurricane can be used to calibrate and evaluate the performance of storm-tide models for maximum and incremental water level and flood extent, and the site-specific effects of storm tide on natural and anthropogenic features of the environment.

Active surge control for variable speed axial compressors.

Science.gov (United States)

Lin, Shu; Yang, Chunjie; Wu, Ping; Song, Zhihuan

2014-09-01

This paper discusses active surge control in variable speed axial compressors. A compression system equipped with a variable area throttle is investigated. Based on a given compressor model, a fuzzy logic controller is designed for surge control and a proportional speed controller is used for speed control. The fuzzy controller uses measurements of the change of pressure rise as well as the change of mass flow to determine the throttle opening. The presented approach does not require the knowledge of system equilibrium or the surge line. Numerical simulations show promising results. The proposed fuzzy logic controller performs better than a backstepping controller and is capable to suppress surge at different operating points. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

Surge analysis of the MAGLEV coil for propulsion and guidance; Jiki fujoshiki tetsudo ni okeru suitei annaiyo coil no surge kaiseki

Energy Technology Data Exchange (ETDEWEB)

Ema, S [Numazu College of Technology, Shizuoka (Japan)

1995-11-20

The MAGLEV (magnetically levitated train) is now well along in development testing in Japan. MAGLEV is unlike conventional railways, so various problems lie in the technology of MAGLEV. One of them is surge analysis of the MAGLEV coil for propulsion and guidance (`coil for propulsion` for short). The coil for propulsion is installed on each side of the outdoor guideway. Thus, the power system of MAGLEV is always exposed to lightning and circuit switching. Accordingly, it is very important to do a rational insulation plan to prevent damage when surges enter the coils. In view of this situation I performed experiments using the mini model coils and clarified impulse voltage distribution at the end of each coil and simulated the surge characteristics by giving the inverted L equivalent circuit to the coil for propulsion. As a result, the measured values and calculated values were almost equal in the surge characteristics. Further, the surge characteristics of the Miyazaki test track and the future MAGLEV were examined. 10 refs., 17 figs., 1 tab.

Use of historical information in extreme surge frequency estimation: case of the marine flooding on the La Rochelle site in France

Science.gov (United States)

Hamdi, Y.; Bardet, L.; Duluc, C.-M.; Rebour, V.

2014-09-01

the storm Xynthia induced an outlier, to illustrate their potentials, to compare their performances and especially to analyze the impact of the use of HI on the extreme surge frequency estimation.

Use of historical information in extreme-surge frequency estimation: the case of marine flooding on the La Rochelle site in France

Science.gov (United States)

Hamdi, Y.; Bardet, L.; Duluc, C.-M.; Rebour, V.

2015-07-01

the storm Xynthia induced an outlier, to illustrate their potentials, to compare their performances and especially to analyze the impact of the use of HI on the extreme-surge frequency estimation.

Pressure-surge mitigation methods in fluid-conveying piping

International Nuclear Information System (INIS)

Shin, Y.W.; Youngdahl, C.K.; Wiedermann, A.H.

1991-01-01

Pressure surges in the heat transport system of nuclear reactor plants can affect the safety and reliability of the plants. Hence the pressure surges must be considered in the design, operation, and maintenance of the plants in order to minimize their occurrence and impacts. The objectives of this paper are to review various methods to control or mitigate the pressure surges, to analyze these methods to gain understanding of the mitigation mechanisms, and examine applicability of the methods to nuclear power plants. 6 refs., 13 figs

Geomagnetic storm forecasting service StormFocus: 5 years online

Science.gov (United States)

Podladchikova, Tatiana; Petrukovich, Anatoly; Yermolaev, Yuri

2018-04-01

Forecasting geomagnetic storms is highly important for many space weather applications. In this study, we review performance of the geomagnetic storm forecasting service StormFocus during 2011-2016. The service was implemented in 2011 at SpaceWeather.Ru and predicts the expected strength of geomagnetic storms as measured by Dst index several hours ahead. The forecast is based on L1 solar wind and IMF measurements and is updated every hour. The solar maximum of cycle 24 is weak, so most of the statistics are on rather moderate storms. We verify quality of selection criteria, as well as reliability of real-time input data in comparison with the final values, available in archives. In real-time operation 87% of storms were correctly predicted while the reanalysis running on final OMNI data predicts successfully 97% of storms. Thus the main reasons for prediction errors are discrepancies between real-time and final data (Dst, solar wind and IMF) due to processing errors, specifics of datasets.

Solar noise storms

CERN Document Server

Elgaroy, E O

2013-01-01

Solar Noise Storms examines the properties and features of solar noise storm phenomenon. The book also presents some theories that can be used to gain a better understanding of the phenomenon. The coverage of the text includes topics that cover the features and behavior of noise storms, such as the observable features of noise storms; the relationship between noise storms and the observable features on the sun; and ordered behavior of storm bursts in the time-frequency plane. The book also covers the spectrum, polarization, and directivity of noise storms. The text will be of great use to astr

Performance of Surge Arrester Installation to Enhance Protection

Directory of Open Access Journals (Sweden)

Mbunwe Muncho Josephine

2017-01-01

Full Text Available The effects of abnormal voltages on power system equipment and appliances in the home have raise concern as most of the equipments are very expensive. Each piece of electrical equipment in an electrical system needs to be protected from surges. To prevent damage to electrical equipment, surge protection considerations are paramount to a well designed electrical system. Lightning discharges are able to damage electric and electronic devices that usually have a low protection level and these are influenced by current or voltage pulses with a relatively low energy, which are induced by lightning currents. This calls for proper designed and configuration of surge arresters for protection on the particular appliances. A more efficient non-linear surge arrester, metal oxide varistor (MOV, should be introduced to handle these surges. This paper shows the selection of arresters laying more emphasis on the arresters for residential areas. In addition, application and installation of the arrester will be determined by the selected arrester. This paper selects the lowest rated surge arrester as it provides insulation when the system is under stress. It also selected station class and distribution class of arresters as they act as an open circuit under normal system operation and to bring the system back to its normal operation mode as the transient voltage is suppressed. Thus, reduces the risk of damage, which the protection measures can be characterized, by the reduction value of the economic loss to an acceptable level.

Empirical STORM-E Model. [I. Theoretical and Observational Basis

Science.gov (United States)

Mertens, Christopher J.; Xu, Xiaojing; Bilitza, Dieter; Mlynczak, Martin G.; Russell, James M., III

2013-01-01

Auroral nighttime infrared emission observed by the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument onboard the Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics (TIMED) satellite is used to develop an empirical model of geomagnetic storm enhancements to E-region peak electron densities. The empirical model is called STORM-E and will be incorporated into the 2012 release of the International Reference Ionosphere (IRI). The proxy for characterizing the E-region response to geomagnetic forcing is NO+(v) volume emission rates (VER) derived from the TIMED/SABER 4.3 lm channel limb radiance measurements. The storm-time response of the NO+(v) 4.3 lm VER is sensitive to auroral particle precipitation. A statistical database of storm-time to climatological quiet-time ratios of SABER-observed NO+(v) 4.3 lm VER are fit to widely available geomagnetic indices using the theoretical framework of linear impulse-response theory. The STORM-E model provides a dynamic storm-time correction factor to adjust a known quiescent E-region electron density peak concentration for geomagnetic enhancements due to auroral particle precipitation. Part II of this series describes the explicit development of the empirical storm-time correction factor for E-region peak electron densities, and shows comparisons of E-region electron densities between STORM-E predictions and incoherent scatter radar measurements. In this paper, Part I of the series, the efficacy of using SABER-derived NO+(v) VER as a proxy for the E-region response to solar-geomagnetic disturbances is presented. Furthermore, a detailed description of the algorithms and methodologies used to derive NO+(v) VER from SABER 4.3 lm limb emission measurements is given. Finally, an assessment of key uncertainties in retrieving NO+(v) VER is presented

Overview of the ARkStorm scenario

Science.gov (United States)

Porter, Keith; Wein, Anne; Alpers, Charles N.; Baez, Allan; Barnard, Patrick L.; Carter, James; Corsi, Alessandra; Costner, James; Cox, Dale; Das, Tapash; Dettinger, Mike; Done, James; Eadie, Charles; Eymann, Marcia; Ferris, Justin; Gunturi, Prasad; Hughes, Mimi; Jarrett, Robert; Johnson, Laurie; Le-Griffin, Hanh Dam; Mitchell, David; Morman, Suzette; Neiman, Paul; Olsen, Anna; Perry, Suzanne; Plumlee, Geoffrey; Ralph, Martin; Reynolds, David; Rose, Adam; Schaefer, Kathleen; Serakos, Julie; Siembieda, William; Stock, Jonathan; Strong, David; Wing, Ian Sue; Tang, Alex; Thomas, Pete; Topping, Ken; Wills, Chris; Jones, Lucile

2011-01-01

coastal communities. Windspeeds in some places reach 125 miles per hour, hurricane-force winds. Across wider areas of the state, winds reach 60 miles per hour. Hundreds of landslides damage roads, highways, and homes. Property damage exceeds $300 billion, most from flooding. Demand surge (an increase in labor rates and other repair costs after major natural disasters) could increase property losses by 20 percent. Agricultural losses and other costs to repair lifelines, dewater (drain) flooded islands, and repair damage from landslides, brings the total direct property loss to nearly $400 billion, of which $20 to $30 billion would be recoverable through public and commercial insurance. Power, water, sewer, and other lifelines experience damage that takes weeks or months to restore. Flooding evacuation could involve 1.5 million residents in the inland region and delta counties. Business interruption costs reach $325 billion in addition to the $400 property repair costs, meaning that an ARkStorm could cost on the order of $725 billion, which is nearly 3 times the loss deemed to be realistic by the ShakeOut authors for a severe southern California earthquake, an event with roughly the same annual occurrence probability. The ARkStorm has several public policy implications: (1) An ARkStorm raises serious questions about the ability of existing federal, state, and local disaster planning to handle a disaster of this magnitude. (2) A core policy issue raised is whether to pay now to mitigate, or pay a lot more later for recovery. (3) Innovative financing solutions are likely to be needed to avoid fiscal crisis and adequately fund response and recovery costs from a similar, real, disaster. (4) Responders and government managers at all levels could be encouraged to conduct risk assessments, and devise the full spectrum of exercises, to exercise ability of their plans to address a similar event. (5) ARkStorm can be a reference point for application of Federal Emergency Ma

Using Bayesian Network as a tool for coastal storm flood impact prediction at Varna Bay (Bulgaria, Western Black Sea)

Science.gov (United States)

Valchev, Nikolay; Eftimova, Petya; Andreeva, Nataliya; Prodanov, Bogdan

2017-04-01

Coastal zone is among the fastest evolving areas worldwide. Ever increasing population inhabiting coastal settlements develops often conflicting economic and societal activities. The existing imbalance between the expansion of these activities, on one hand, and the potential to accommodate them in a sustainable manner, on the other, becomes a critical problem. Concurrently, coasts are affected by various hydro-meteorological phenomena such as storm surges, heavy seas, strong winds and flash floods, which intensities and occurrence frequency is likely to increase due to the climate change. This implies elaboration of tools capable of quick prediction of impact of those phenomena on the coast and providing solutions in terms of disaster risk reduction measures. One such tool is Bayesian network. Proposed paper describes the set-up of such network for Varna Bay (Bulgaria, Western Black Sea). It relates near-shore storm conditions to their onshore flood potential and ultimately to relevant impact as relative damage on coastal and manmade environment. Methodology for set-up and training of the Bayesian network was developed within RISC-KIT project (Resilience-Increasing Strategies for Coasts - toolKIT). Proposed BN reflects the interaction between boundary conditions, receptors, hazard, and consequences. Storm boundary conditions - maximum significant wave height and peak surge level, were determined on the basis of their historical and projected occurrence. The only hazard considered in this study is flooding characterized by maximum inundation depth. BN was trained with synthetic events created by combining estimated boundary conditions. Flood impact was modeled with the process-based morphodynamical model XBeach. Restaurants, sport and leisure facilities, administrative buildings, and car parks were introduced in the network as receptors. Consequences (impact) are estimated in terms of relative damage caused by given inundation depth. National depth

Harmful effects of lightning surge discharge on communications terminal equipments

International Nuclear Information System (INIS)

Liang, Sisi; Xu, Xiaoying; Tao, Zhigang; Dai, Yanling

2013-01-01

The interference problem of lightning surges on electronic and telecommunication products were examined, and a series of experiments were conducted to analyze the failure situations to find out the mechanisms of failures caused by the lightning surge. In addition, the ways in which lightning surges damaged equipment were deduced. It was found that failure positions were scattered and appeared in groups, and most of them were ground discharge. Internet access transformer had high withstand-voltage under the lightning pulse, and the lightning surge seldom passed through the internet access transformer. The lightning current can release to the ground via the computer network adapter of the terminal user. The study will help to improve the performance of lightning surge protection circuit and protection level.

Pre-swirl mechanism in front of a centrifugal compressor: effects on surge line and on unsteady phenomena in surge area

Directory of Open Access Journals (Sweden)

Danlos Amélie

2017-01-01

Full Text Available Using a pre-swirl mechanism upstream an impeller of a compressor allows to modify its characteristics curve, while weakly damaging its efficiency. Another consequence of the pre-swirl is to push back the surge line limit and to increase the operation zone towards the low flow rate limits. A centrifugal compressor has been modified in order to add a swirl generator device upstream the impeller. The incidence values of blades can vary from 0° (no pre-swirl to ±90°. The variation of the stator blades incidence has several main consequences: to allow a flow rate adjustment with a good efficiency conservation, to increase the angular velocity with a constant shaft power, to produce a displacement of the surge line limit. In this paper, the results of experimental studies are presented to analyze the surge line and the intensity of unsteady phenomena when the compressor works in its surge area.

The destruction influence of pulse and surge currents on overvoltage protection

International Nuclear Information System (INIS)

Glasa, M.; Huettner, L.

2012-01-01

This article deals about the influences caused during the active operation process of the surge arrester against the pulse and surge currents. It also refers about a lightning, the characteristic of lightning and about the lightning (surge) currents caused its influence. One parts of the article is focused on a total elimination of surge current energy, and on an ineffective operation, which leads to partially or totally destruction of a protection element. There is a comparison with two basic types of surge arresters (spark gap and varistor based arresters), and theirs re-effectiveness on prescribed level. (Authors)

Surge dynamics on Bering Glacier, Alaska, in 2008–2011

Directory of Open Access Journals (Sweden)

M. Braun

2012-11-01

Full Text Available A surge cycle of the Bering Glacier system, Alaska, is examined using observations of surface velocity obtained using synthetic aperture radar (SAR offset tracking, and elevation data obtained from the University of Alaska Fairbanks LiDAR altimetry program. After 13 yr of quiescence, the Bering Glacier system began to surge in May 2008 and had two stages of accelerated flow. During the first stage, flow accelerated progressively for at least 10 months and reached peak observed velocities of ~ 7 m d−1. The second stage likely began in 2010. By 2011 velocities exceeded 9 m d−1 or ~ 18 times quiescent velocities. Fast flow continued into July 2011. Surface morphology indicated slowing by fall 2011; however, it is not entirely clear if the surge is yet over. The quiescent phase was characterized by small-scale acceleration events that increased driving stresses up to 70%. When the surge initiated, synchronous acceleration occurred throughout much of the glacier length. Results suggest that downstream propagation of the surge is closely linked to the evolution of the driving stress during the surge, because driving stress appears to be tied to the amount of resistive stress provided by the bed. In contrast, upstream acceleration and upstream surge propagation is not dependent on driving stress evolution.

Compressor Surge Control Design Using Linear Matrix Inequality Approach

OpenAIRE

Uddin, Nur; Gravdahl, Jan Tommy

2017-01-01

A novel design for active compressor surge control system (ASCS) using linear matrix inequality (LMI) approach is presented and including a case study on piston-actuated active compressor surge control system (PAASCS). The non-linear system dynamics of the PAASCS is transformed into linear parameter varying (LPV) system dynamics. The system parameters are varying as a function of the compressor performance curve slope. A compressor surge stabilization problem is then formulated as a LMI probl...

The Genesis of Tropical Cyclone Bilis (2000) Associated with Cross-equatorial Surges

Institute of Scientific and Technical Information of China (English)

XU Yamei

2011-01-01

The purpose of this paper is to explore how a tropical cyclone forms from a pre-existing large-scale depression which has been observed and associated with cross-equatorial surges in the western North Pacific. Tropical cyclone Bilis (2000) was selected as the case to study. The research data used are from the results of the non-hydrostatic mesoscale model (MM5), which has successfully simulated the transformation of a pre-existing weak large-scale tropical depression into a strong tropical storm. The scale separation technique is used to separate the synoptic-scale and sub-synoptic-scale fields from the model output fields. The scale-separated fields show that the pre-existing synoptic-scale tropical depression and the subsynoptic scale tropical cyclone formed later were different scale systems from beginning to end. It is also shown that the pre-existing synoptic-scale tropical depression did not contract to become the tropical cyclone. A series of weak, sub-synoptic-scale low and high pressure systems appeared and disappeared in the synopticscale depression, with one of the low systems near the center of the synoptic-scale depression having deepened to become the tropical cyclone. The roles of the synoptic-scale flow and the sub-synoptic scale disturbances in the formation of the tropical cyclone are investigated by diagnoses of the scale-separated vertical vorticity equation. The results show that the early development of the sub-synoptic scale vortex was fundamentally dependent on the strengthening synoptic-scale environmental depression. The depression was strengthened by cross-equatorial surges, which increased the convergence of the synoptic-scale depression at low levels and triggered the formation of the tropical cyclone.

Proposed Strategies for DWPF Melter Off-Gas Surge Control

International Nuclear Information System (INIS)

CHOI, ALEXANDERS.

2004-01-01

Off-gas surging is inherent to the operation of slurry-fed melters. Although the melter design and the feed chemistry are both known to significantly affect off-gas surging, the frequency and intensity of surges are in essence unpredictable. In typical off-gas surges, both condensable and non condensable flows spike simultaneously. Condensable or steam surges have been observed to occur as the boiling water layer occasionally falls into the crevices of the cold cap or flows over the edges of the cold cap, thereby coming in contact with the melt surface. The resulting steam surges can pressurize the melter considerably and, therefore, are responsible for the bulk of pressure transients that propagate throughout the off-gas system. The non condensable surges occur as the calcine gases that have been accumulating within the cold cap finally build up enough pressure to be released through the temporary openings of the cold cap. The analysis of off-gas data has shown that over 90 of the gas released during a surge is due to steam.1 Therefore, it is essential to have a large inventory of water in the cold cap for any significant pressure spikes to occur. With the Melter 2 vapor space temperature typically running at 720C, the water layer in the cold cap will quickly evaporate once the feeding stops, and the potential for any large pressure spikes should practically cease to exist. The analysis also showed that large pressure spikes well above 2 inches H2O cannot occur under the steam surge scenarios described above. More severe conditions should prevail and one such condition would be that the feed materials form a mound with a growing lake on top, while the melt below remains very fluidic due to its low viscosity, thus resulting in greater movements both in the lateral as well as vertical directions. Once the mound begins to grow, its rate should accelerate, since the heat transfer rate to the upper regions of the cold cap is inversely proportional to the cold cap

Surrogate modeling of joint flood risk across coastal watersheds

Science.gov (United States)

Bass, Benjamin; Bedient, Philip

2018-03-01

This study discusses the development and performance of a rapid prediction system capable of representing the joint rainfall-runoff and storm surge flood response of tropical cyclones (TCs) for probabilistic risk analysis. Due to the computational demand required for accurately representing storm surge with the high-fidelity ADvanced CIRCulation (ADCIRC) hydrodynamic model and its coupling with additional numerical models to represent rainfall-runoff, a surrogate or statistical model was trained to represent the relationship between hurricane wind- and pressure-field characteristics and their peak joint flood response typically determined from physics based numerical models. This builds upon past studies that have only evaluated surrogate models for predicting peak surge, and provides the first system capable of probabilistically representing joint flood levels from TCs. The utility of this joint flood prediction system is then demonstrated by improving upon probabilistic TC flood risk products, which currently account for storm surge but do not take into account TC associated rainfall-runoff. Results demonstrate the source apportionment of rainfall-runoff versus storm surge and highlight that slight increases in flood risk levels may occur due to the interaction between rainfall-runoff and storm surge as compared to the Federal Emergency Management Association's (FEMAs) current practices.

Improved PV system reliability results from surge evaluations at Sandia National Laboratories

International Nuclear Information System (INIS)

Russell H. Bonn; Sigifredo Gonzalez

2000-01-01

Electrical surges on ac and dc inverter power wiring and diagnostic cables have the potential to shorten the lifetime of power electronics. These surges may be caused by either nearby lightning or capacitor switching transients. This paper contains a description of ongoing surge evaluations of PV power electronics and surge mitigation hardware at Sandia

Surge of Bering Glacier and Bagley Ice Field: Parameterization of surge characteristics based on automated analysis of crevasse image data and laser altimeter data

Science.gov (United States)

Stachura, M.; Herzfeld, U. C.; McDonald, B.; Weltman, A.; Hale, G.; Trantow, T.

2012-12-01

The dynamical processes that occur during the surge of a large, complex glacier system are far from being understood. The aim of this paper is to derive a parameterization of surge characteristics that captures the principle processes and can serve as the basis for a dynamic surge model. Innovative mathematical methods are introduced that facilitate derivation of such a parameterization from remote-sensing observations. Methods include automated geostatistical characterization and connectionist-geostatistical classification of dynamic provinces and deformation states, using the vehicle of crevasse patterns. These methods are applied to analyze satellite and airborne image and laser altimeter data collected during the current surge of Bering Glacier and Bagley Ice Field, Alaska.

Objective measurement of postocclusion surge during phacoemulsification in human eye-bank eyes.

Science.gov (United States)

Georgescu, Dan; Payne, Marielle; Olson, Randall J

2007-03-01

To objectively compare the postocclusion vacuum surge among different phacoemulsification machines and devices. Experimental study. Infiniti, Legacy, Millennium, and Sovereign were tested in an eye-bank eye. All the machines were tested with 20-gauge non-ABS tips, 430 mm Hg vacuum pressure, 24 ml/minute aspiration rate, peristaltic pump, and 75 cm bottle height. In addition, Infiniti and Legacy were also tested with 20-gauge bypass tips (ABS), 125 cm bottle height, and 40 ml/minute flow rate. We also tested 19-gauge tips with Infiniti and Sovereign and the venturi pump for Millennium. Significant differences were found between all the machines tested with Millennium peristaltic generating the least and Millennium Venturi the most surge. ABS tips significantly decreased the surge for Legacy but not for Infiniti. Cruise Control (CC) had a significant effect on Sovereign but not on Millennium. Increasing the bottle height decreased surge while increasing the flow increased surge for both Infiniti and Legacy. The 19-gauge tips increased surge for both Infiniti and Sovereign. Surge varied over a range of 40 microm to more than 2 mm. ABS and CC decrease surge, especially when the machine is not functioning near the limits of surge prevention. Certain parameters, such as a 19-gauge tip and high flow, dramatically increased surge, whereas elevating the bottle ameliorates it. Understanding the impact of all these features will help in minimizing the problem.

Learning Storm

CERN Document Server

Jain, Ankit

2014-01-01

If you are a Java developer who wants to enter into the world of real-time stream processing applications using Apache Storm, then this book is for you. No previous experience in Storm is required as this book starts from the basics. After finishing this book, you will be able to develop not-so-complex Storm applications.

Present dynamics and future prognosis of a slowly surging glacier

Directory of Open Access Journals (Sweden)

G. E. Flowers

2011-03-01

Full Text Available Glacier surges are a well-known example of an internal dynamic oscillation whose occurrence is not a direct response to the external climate forcing, but whose character (i.e. period, amplitude, mechanism may depend on the glacier's environmental or climate setting. We examine the dynamics of a small (∼5 km² valley glacier in Yukon, Canada, where two previous surges have been photographically documented and an unusually slow surge is currently underway. To characterize the dynamics of the present surge, and to speculate on the future of this glacier, we employ a higher-order flowband model of ice dynamics with a regularized Coulomb-friction sliding law in both diagnostic and prognostic simulations. Diagnostic (force balance calculations capture the measured ice-surface velocity profile only when non-zero basal water pressures are prescribed over the central region of the glacier, coincident with where evidence of the surge has been identified. This leads to sliding accounting for 50–100% of the total surface motion in this region. Prognostic simulations, where the glacier geometry evolves in response to a prescribed surface mass balance, reveal a significant role played by a bedrock ridge beneath the current equilibrium line of the glacier. Ice thickening occurs above the ridge in our simulations, until the net mass balance reaches sufficiently negative values. We suggest that the bedrock ridge may contribute to the propensity for surges in this glacier by promoting the development of the reservoir area during quiescence, and may permit surges to occur under more negative balance conditions than would otherwise be possible. Collectively, these results corroborate our interpretation of the current glacier flow regime as indicative of a slow surge that has been ongoing for some time, and support a relationship between surge incidence or character and the net mass balance. Our results also highlight the importance of glacier bed

Current understanding of magnetic storms: Storm-substorm relationships

International Nuclear Information System (INIS)

Kamide, Y.; Gonzalez, W.D.; Baumjohann, W.; Daglis, I.A.; Grande, M.; Joselyn, J.A.; Singer, H.J.; McPherron, R.L.; Phillips, J.L.; Reeves, E.G.; Rostoker, G.; Sharma, A.S.; Tsurutani, B.T.

1998-01-01

This paper attempts to summarize the current understanding of the storm/substorm relationship by clearing up a considerable amount of controversy and by addressing the question of how solar wind energy is deposited into and is dissipated in the constituent elements that are critical to magnetospheric and ionospheric processes during magnetic storms. (1) Four mechanisms are identified and discussed as the primary causes of enhanced electric fields in the interplanetary medium responsible for geomagnetic storms. It is pointed out that in reality, these four mechanisms, which are not mutually exclusive, but interdependent, interact differently from event to event. Interplanetary coronal mass ejections (ICMEs) and corotating interaction regions (CIRs) are found to be the primary phenomena responsible for the main phase of geomagnetic storms. The other two mechanisms, i.e., HILDCAA (high-intensity, long-duration, continuous auroral electrojet activity) and the so-called Russell-McPherron effect, work to make the ICME and CIR phenomena more geoeffective. The solar cycle dependence of the various sources in creating magnetic storms has yet to be quantitatively understood. (2) A serious controversy exists as to whether the successive occurrence of intense substorms plays a direct role in the energization of ring current particles or whether the enhanced electric field associated with southward IMF enhances the effect of substorm expansions. While most of the Dst variance during magnetic storms can be solely reproduced by changes in the large-scale electric field in the solar wind and the residuals are uncorrelated with substorms, recent satellite observations of the ring current constituents during the main phase of magnetic storms show the importance of ionospheric ions. This implies that ionospheric ions, which are associated with the frequent occurrence of intense substorms, are accelerated upward along magnetic field lines, contributing to the energy density of the

30 CFR 56.16002 - Bins, hoppers, silos, tanks, and surge piles.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Bins, hoppers, silos, tanks, and surge piles... MINES Materials Storage and Handling § 56.16002 Bins, hoppers, silos, tanks, and surge piles. (a) Bins, hoppers, silos, tanks, and surge piles, where loose unconsolidated materials are stored, handled or...

30 CFR 57.16002 - Bins, hoppers, silos, tanks, and surge piles.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Bins, hoppers, silos, tanks, and surge piles... NONMETAL MINES Materials Storage and Handling § 57.16002 Bins, hoppers, silos, tanks, and surge piles. (a) Bins, hoppers, silos, tanks, and surge piles, where loose unconsolidated materials are stored, handled...

Surge recovery techniques for the Tevatron cold compressors

International Nuclear Information System (INIS)

Martinez, A.; Klebaner, A.L.; Makara, J.N.; Theilacker, J.C.; Fermilab

2006-01-01

The Fermilab Tevatron cryogenic system utilizes high-speed centrifugal cold compressors, made by Ishikawajima-Harima Heavy Industries Co. Ltd. (IHI), for high-energy operations [1]. The compressor is designed to pump 60 g/s of 3.6 K saturated helium vapor at a pressure ratio of 2.8, with an off-design range of 40 to 70 g/s and operating speeds between 40 and 95 krpm. Since initial commissioning in 1993, Tevatron transient conditions such as quench recovery have led to multiple-location machine trips as a result of the cold compressors entering the surge regime. Historically, compressors operating at lower inlet pressures and higher speeds have been especially susceptible to these machine trips and it was not uncommon to have multiple compressor trips during large multiple-house quenches. In order to cope with these events and limit accelerator down time, surge recovery techniques have been implemented in an attempt to prevent the compressors from tripping once the machine entered this surge regime. This paper discusses the different methods of surge recovery that have been employed. Data from tests performed at the Cryogenic Test Facility at Fermilab as well as actual Tevatron operational data were utilized. In order to aid in the determination of the surge region, a full mapping study was undertaken to characterize the entire pressure field of the cold compressor. These techniques were then implemented and tested at several locations in the Tevatron with some success

Dependence between sea surge, river flow and precipitation in south and west Britain

Directory of Open Access Journals (Sweden)

C. Svensson

2004-01-01

Full Text Available Estuaries around Great Britain may be at heightened risk of flooding because of the simultaneous occurrence of extreme sea surge and river flow, both of which may be caused by mid-latitude cyclones. A measure especially suited for extremes was employed to estimate dependence between river flow and sea surge. To assist in the interpretation of why flow-surge dependence occurs in some areas and not in others, the dependence between precipitation and surge and between precipitation and river flow was also studied. Case studies of the meteorological situations leading to high surges and/or river flows were also carried out. The present study concerns catchments draining to the south and west coasts of Great Britain. Statistically significant dependence between river flow and daily maximum sea surge may be found at catchments spread along most of this coastline. However, higher dependence is generally found in catchments in hilly areas with a southerly to westerly aspect. Here, precipitation in south-westerly airflow, which is generally the quadrant of prevailing winds, will be enhanced orographically as the first higher ground is encountered. The sloping catchments may respond quickly to the abundant rainfall and the flow peak may arrive in the estuary on the same day as a large sea surge is produced by the winds and low atmospheric pressure associated with the cyclone. There are three regions where flow-surge dependence is strong: the western part of the English south coast, southern Wales and around the Solway Firth. To reduce the influence of tide-surge interaction on the dependence analysis, the dependence between river flow and daily maximum surge occurring at high tide was estimated. The general pattern of areas with higher dependence is similar to that using the daily maximum surge. The dependence between river flow and daily maximum sea surge is often strongest when surge and flow occur on the same day. The west coast from Wales and

Effects of storm waves on rapid deposition of sediment in the Yangtze Estuary channel

Directory of Open Access Journals (Sweden)

Xu Fumin

2008-03-01

Full Text Available Recent research on short-term topographic change in the Yangtze Estuary channel under storm surge conditions is briefly summarized. The mild-slope, Boussinesq and action balance equations are compared and analyzed. The action balance equation, SWAN, was used as a wave numerical model to forecast strong storm waves in the Yangtze Estuary. The spherical coordinate system and source terms used in the equation are described in this paper. The significant wave height and the wave orbital motion velocity near the bottom of the channel during 20 m/s winds in the EES direction were simulated, and the model was calibrated with observation data of winds and waves generated by Tropical Cyclone 9912. The distribution of critical velocity for incipient motion along the bottom was computed according to the threshold velocity formula for bottom sediment. The mechanism of rapid deposition is analyzed based on the difference between the root-mean-square value of the near-bottom wave orbital motion velocity and the bottom critical tractive velocity. The results show that a large amount of bottom sediments from Hengsha Shoal and Jiuduan Shoal are lifted into the water body when 20 m/s wind is blowing in the EES direction. Some of the sediments may enter the channel with the cross-channel current, causing serious rapid deposition. Finally, the tendency of the storm to induce rapid deposition in the Yangtze Estuary channel zone is analyzed.

Exercising Tactically for Taming Postmeal Glucose Surges

Directory of Open Access Journals (Sweden)

Elsamma Chacko

2016-01-01

Full Text Available This review seeks to synthesize data on the timing, intensity, and duration of exercise found scattered over some 39 studies spanning 3+ decades into optimal exercise conditions for controlling postmeal glucose surges. The results show that a light aerobic exercise for 60 min or moderate activity for 20–30 min starting 30 min after meal can efficiently blunt the glucose surge, with minimal risk of hypoglycemia. Exercising at other times could lead to glucose elevation caused by counterregulation. Adding a short bout of resistance exercise of moderate intensity (60%–80%  VO2max to the aerobic activity, 2 or 3 times a week as recommended by the current guidelines, may also help with the lowering of glucose surges. On the other hand, high-intensity exercise (>80%  VO2max causes wide glucose fluctuations and its feasibility and efficacy for glucose regulation remain to be ascertained. Promoting the kind of physical activity that best counters postmeal hyperglycemia is crucial because hundreds of millions of diabetes patients living in developing countries and in the pockets of poverty in the West must do without medicines, supplies, and special diets. Physical activity is the one tool they may readily utilize to tame postmeal glucose surges. Exercising in this manner does not violate any of the current guidelines, which encourage exercise any time.

Exercising Tactically for Taming Postmeal Glucose Surges.

Science.gov (United States)

Chacko, Elsamma

2016-01-01

This review seeks to synthesize data on the timing, intensity, and duration of exercise found scattered over some 39 studies spanning 3+ decades into optimal exercise conditions for controlling postmeal glucose surges. The results show that a light aerobic exercise for 60 min or moderate activity for 20-30 min starting 30 min after meal can efficiently blunt the glucose surge, with minimal risk of hypoglycemia. Exercising at other times could lead to glucose elevation caused by counterregulation. Adding a short bout of resistance exercise of moderate intensity (60%-80%  VO2max) to the aerobic activity, 2 or 3 times a week as recommended by the current guidelines, may also help with the lowering of glucose surges. On the other hand, high-intensity exercise (>80%  VO2max) causes wide glucose fluctuations and its feasibility and efficacy for glucose regulation remain to be ascertained. Promoting the kind of physical activity that best counters postmeal hyperglycemia is crucial because hundreds of millions of diabetes patients living in developing countries and in the pockets of poverty in the West must do without medicines, supplies, and special diets. Physical activity is the one tool they may readily utilize to tame postmeal glucose surges. Exercising in this manner does not violate any of the current guidelines, which encourage exercise any time.

Methodology for surge pressure evaluation in a water injection system

Energy Technology Data Exchange (ETDEWEB)

Meliande, Patricia; Nascimento, Elson A. [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Dept. de Engenharia Civil; Mascarenhas, Flavio C.B. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Lab. de Hidraulica Computacional; Dandoulakis, Joao P. [SHELL of Brazil, Rio de Janeiro, RJ (Brazil)

2009-07-01

Predicting transient effects, known as surge pressures, is of high importance for offshore industry. It involves detailed computer modeling that attempts to simulate the complex interaction between flow line and fluid in order to ensure efficient system integrity. Platform process operators normally raise concerns whether the water injection system is adequately designed or not to be protected against possible surge pressures during sudden valve closure. This report aims to evaluate the surge pressures in Bijupira and Salema water injection systems due to valve closure, through a computer model simulation. Comparisons among the results from empirical formulations are discussed and supplementary analysis for Salema system were performed in order to define the maximum volumetric flow rate for which the design pressure was able to withstand. Maximum surge pressure values of 287.76 bar and 318.58 bar, obtained in Salema and Bijupira respectively, using empirical formulations have surpassed the operating pressure design, while the computer model results have pointed the greatest surge pressure value of 282 bar in Salema system. (author)

Developing models for patient flow and daily surge capacity research.

Science.gov (United States)

Asplin, Brent R; Flottemesch, Thomas J; Gordon, Bradley D

2006-11-01

Between 1993 and 2003, visits to U.S. emergency departments (EDs) increased by 26%, to a total of 114 million visits annually. At the same time, the number of U.S. EDs decreased by more than 400, and almost 200,000 inpatient hospital beds were taken out of service. In this context, the adequacy of daily surge capacity within the system is clearly an important issue. However, the research agenda on surge capacity thus far has focused primarily on large-scale disasters, such as pandemic influenza or a serious bioterrorism event. The concept of daily surge capacity and its relationship to the broader research agenda on patient flow is a relatively new area of investigation. In this article, the authors begin by describing the overlap between the research agendas on daily surge capacity and patient flow. Next, they propose two models that have potential applications for both daily surge capacity and hospitalwide patient-flow research. Finally, they identify potential research questions that are based on applications of the proposed research models.

Surge of plasma waves in an inhomogeneous plasma

International Nuclear Information System (INIS)

Benhassine, Mohammed

1985-01-01

The first part of this research thesis addresses the propagation of waves in a plasma. It presents the equation of propagation of an electromagnetic wave in a plasma without magnetic field, and analyses the propagation in an inhomogeneous medium. The second part addresses the wave-particle interaction: interaction between electrons and an electromagnetic wave, between electrons and an electrostatic wave (trapping), and between electrons and a localised electric field. The third chapter presents the analytic theory of oscillations of a cold plasma (macroscopic equations in Lagrangian coordinates, analytic solution before surge). The next chapter discusses physical interpretations before the wave surge, after the wave surge, and about energy exchange (within or outside of resonance). Numerical simulations and their results are then reported and discussed. The sixth chapter addresses the case of an electrostatic wave surge in a hot plasma. It notably addresses the following aspects: equivalence between the description of moments and the Waterbag model, interaction between non linearity and thermal effects, variation of electric field amplitude with temperature. Results of numerical simulations are presented, and the last part addresses experimental predictions for microwaves-plasma interaction and laser-matter interaction [fr

Structure design of water discharge surge tank of nuclear power plant

International Nuclear Information System (INIS)

Wang Fang; Hou Shuqiang

2015-01-01

Drainage is an important function of water discharge surge tank in nuclear power plant. There is little wall and beam inside the water discharge surge tank due to the requirement of major work, which is different from the general structure. Taking water discharge surge tank of nuclear power plant for example, concerned problems are expatiated in the structure scheme of water discharge surge tank, and important structural components are analyzed. Structural analysis model is established by ANSYS finite element analysis. A comprehensive and numerical analysis is performed for different combinations of structural model, and the internal force of structure is extracted. Finally, suggestions for design of similar structure are proposed. (authors)

Hindcasting of Storm Surges, Currents, and Waves at Lower Delaware Bay during Hurricane Isabel

Science.gov (United States)

Salehi, M.

2017-12-01

Hurricanes are a major threat to coastal communities and infrastructures including nuclear power plants located in low-lying coastal zones. In response, their sensitive elements should be protected by smart design to withstand against drastic impact of such natural phenomena. Accurate and reliable estimate of hurricane attributes is the first step to that effort. Numerical models have extensively grown over the past few years and are effective tools in modeling large scale natural events such as hurricane. The impact of low probability hurricanes on the lower Delaware Bay is investigated using dynamically coupled meteorological, hydrodynamic, and wave components of Delft3D software. Efforts are made to significantly reduce the computational overburden of performing such analysis for the industry, yet keeping the same level of accuracy at the area of study (AOS). The model is comprised of overall and nested domains. The overall model domain includes portion of Atlantic Ocean, Delaware, and Chesapeake bays. The nested model domain includes Delaware Bay, its floodplain, and portion of the continental shelf. This study is portion of a larger modeling effort to study the impact of low probability hurricanes on sensitive infrastructures located at the coastal zones prone to hurricane activity. The AOS is located on the east bank of Delaware Bay almost 16 miles upstream of its mouth. Model generated wind speed, significant wave height, water surface elevation, and current are calibrated for hurricane Isabel (2003). The model calibration results agreed reasonably well with field observations. Furthermore, sensitivity of surge and wave responses to various hurricane parameters was tested. In line with findings from other researchers, accuracy of wind field played a major role in hindcasting the hurricane attributes.

NATIONAL WEATHER SERVICE MARINE PRODUCTS VIA INTERNET

Science.gov (United States)

the search's key words. Tide Predictions, Observations and Storm Surge Forecasts Near real-time Water , Extratropical Water Level Forecasts are available from the National Weather Service's Meteorological Development Laboratory. Status maps are provided to give the user a quick overview of a region. Forecasts of storm surge

Geomagnetic storms, super-storms, and their impacts on GPS-based navigation systems

Science.gov (United States)

Astafyeva, E.; Yasyukevich, Yu.; Maksikov, A.; Zhivetiev, I.

2014-07-01

Using data of GPS receivers located worldwide, we analyze the quality of GPS performance during four geomagnetic storms of different intensity: two super-storms and two intense storms. We show that during super-storms the density of GPS Losses-of-Lock (LoL) increases up to 0.25% at L1 frequency and up to 3% at L2 frequency, and up to 0.15% (at L1) and 1% (at L2) during less intense storms. Also, depending on the intensity of the storm time ionospheric disturbances, the total number of total electron content (TEC) slips can exceed from 4 to 40 times the quiet time level. Both GPS LoL and TEC slips occur during abrupt changes of SYM-H index of geomagnetic activity, i.e., during the main phase of geomagnetic storms and during development of ionospheric storms. The main contribution in the total number of GPS LoL was found to be done by GPS sites located at low and high latitudes, whereas the area of numerous TEC slips seemed to mostly correspond to the boundary of the auroral oval, i.e., region with intensive ionospheric irregularities. Our global maps of TEC slips show where the regions with intense irregularities of electron density occur during geomagnetic storms and will let us in future predict appearance of GPS errors for geomagnetically disturbed conditions.

Surge protective device response to steep front transient in low voltage circuit

Energy Technology Data Exchange (ETDEWEB)

Marcuz, J.; Binczak, S.; Bilbault, J.M. [Universite de Bourgogne, Dijon (France)], Emails: jerome.marcuz@ laposte.net, stbinc@u-bourgogne.fr, bilbault@u-bourgogne.fr; Girard, F. [ADEE Electronic, Pont de Pany (France)

2007-07-01

Surge propagation on cables of electrical or data lines leads to a major protection problem as the number of equipment based on solid-state circuits or microprocessors increases. Sub-microsecond components of real surge waveform has to be taken into account for a proper protection even in the case of surges caused by indirect lightning effects. The response of a model of transient voltage suppressor diode based surge protection device (SPD) to fast front transient is analytically studied, then compared to simulations, including the lines connected to the SPD and to the protected equipment. (author)

Distribution of auroral surges in the evening sector

International Nuclear Information System (INIS)

Kidd, S.R.; Rostoker, G.

1991-01-01

Over the past dacades a large statistical data base has been gathered consisting of both ground-based magnetometer and all-sky camera records from which researchers have inferred the distribution of substorm expansive phase events across the nighttime sector. Almost without exception, the activity distribution has been based on single station data acquired over periods of years. However, to truly establish the occurrence frequency of substorm expansive phase events, it is necessary to view the entire nighttime sector instantaneously in the light of evidence which shows that more than one expansive phase disturbance can be in progress across the broad expanse of the evening sector. In this paper, the authors study the distribution of regions of localized auroral luminosity in the poleward portion of the evening sectorauroral oval using images in the ultraviolet portion of the auroral spectrum acquired by the Viking satellite over 9 months in 1986. They find that auroral surge activity peaks in the hour before local magnetic midnight, with the probability of detecting a surge steadily decreasing to 10% of the probability of finding a surge in the hour prior to midnight as one moves westward towards 1,900 MLT. They show that their conclusion is not dependent on the threshold chosen for surge identification over a reasonable portion of the intensity range covered by the Viking imager. They further show that for the interval of several months near sunspot minimum in 1986 there is better than a 90% chance that no surge will be detected in a 1-hour range of magnetic local time if one were to sample that segment of the auroral oval at any arbitrary time

Proxy records of Holocene storm events in coastal barrier systems: Storm-wave induced markers

Science.gov (United States)

Goslin, Jérôme; Clemmensen, Lars B.

2017-10-01

Extreme storm events in the coastal zone are one of the main forcing agents of short-term coastal system behavior. As such, storms represent a major threat to human activities concentrated along the coasts worldwide. In order to better understand the frequency of extreme events like storms, climate science must rely on longer-time records than the century-scale records of instrumental weather data. Proxy records of storm-wave or storm-wind induced activity in coastal barrier systems deposits have been widely used worldwide in recent years to document past storm events during the last millennia. This review provides a detailed state-of-the-art compilation of the proxies available from coastal barrier systems to reconstruct Holocene storm chronologies (paleotempestology). The present paper aims (I) to describe the erosional and depositional processes caused by storm-wave action in barrier and back-barrier systems (i.e. beach ridges, storm scarps and washover deposits), (ii) to understand how storm records can be extracted from barrier and back-barrier sedimentary bodies using stratigraphical, sedimentological, micro-paleontological and geochemical proxies and (iii) to show how to obtain chronological control on past storm events recorded in the sedimentary successions. The challenges that paleotempestology studies still face in the reconstruction of representative and reliable storm-chronologies using these various proxies are discussed, and future research prospects are outlined.

The CI-Flow Project: A System for Total Water Level Prediction from the Summit to the Sea

Science.gov (United States)

2011-11-01

round and may be applied to all types of coastal storms , including intense cool- season extratropical cyclones (i.e., nor’easters). In addition...associated with waves, tides, storm surge, rivers, and rainfall, including interactions at the tidal/surge interface Within this project, Cl-FLOW addresses...presented for Hurricane Isabel (2003), Hurricane Earl (20I0), and Tropical Storm Nicole (2010) for the Tar -Pamlico and Neuse River basins of North

The Framework of a Coastal Hazards Model - A Tool for Predicting the Impact of Severe Storms

Science.gov (United States)

Barnard, Patrick L.; O'Reilly, Bill; van Ormondt, Maarten; Elias, Edwin; Ruggiero, Peter; Erikson, Li H.; Hapke, Cheryl; Collins, Brian D.; Guza, Robert T.; Adams, Peter N.; Thomas, Julie

2009-01-01

The U.S. Geological Survey (USGS) Multi-Hazards Demonstration Project in Southern California (Jones and others, 2007) is a five-year project (FY2007-FY2011) integrating multiple USGS research activities with the needs of external partners, such as emergency managers and land-use planners, to produce products and information that can be used to create more disaster-resilient communities. The hazards being evaluated include earthquakes, landslides, floods, tsunamis, wildfires, and coastal hazards. For the Coastal Hazards Task of the Multi-Hazards Demonstration Project in Southern California, the USGS is leading the development of a modeling system for forecasting the impact of winter storms threatening the entire Southern California shoreline from Pt. Conception to the Mexican border. The modeling system, run in real-time or with prescribed scenarios, will incorporate atmospheric information (that is, wind and pressure fields) with a suite of state-of-the-art physical process models (that is, tide, surge, and wave) to enable detailed prediction of currents, wave height, wave runup, and total water levels. Additional research-grade predictions of coastal flooding, inundation, erosion, and cliff failure will also be performed. Initial model testing, performance evaluation, and product development will be focused on a severe winter-storm scenario developed in collaboration with the Winter Storm Working Group of the USGS Multi-Hazards Demonstration Project in Southern California. Additional offline model runs and products will include coastal-hazard hindcasts of selected historical winter storms, as well as additional severe winter-storm simulations based on statistical analyses of historical wave and water-level data. The coastal-hazards model design will also be appropriate for simulating the impact of storms under various sea level rise and climate-change scenarios. The operational capabilities of this modeling system are designed to provide emergency planners with

EroGRASS : Failure of grass cover layers at seaward and shoreward dike slopes. design, construction and performance

NARCIS (Netherlands)

Verhagen, H.J.; Verheij, H.J.; Cao, T.M.; Dassanayake, D.; Roelvink, D.; Piontkowitz, T.

2009-01-01

A large number of the dikes in the North Sea and Baltic Sea regions are covered with grass that is exposed to hydraulic loading from waves and currents during storm surges. During previous storm surges the grass cover layers often showed large strength and remained undamaged. A clear physical

Community health facility preparedness for a cholera surge in Haiti.

Science.gov (United States)

Mobula, Linda Meta; Jacquet, Gabrielle A; Weinhauer, Kristin; Alcidas, Gladys; Thomas, Hans-Muller; Burnham, Gilbert

2013-01-01

With increasing population displacement and worsening water insecurity after the 2010 earthquake, Haiti experienced a large cholera outbreak. Our goal was to evaluate the strengths and weaknesses of seven community health facilities' ability to respond to a surge in cholera cases. Since 2010, Catholic Relief Services (CRS) with a number of public and private donors has been working with seven health facilities in an effort to reduce morbidity and mortality from cholera infection. In November 2012, CRS through the Centers for Disease Control and Prevention (CDC)'s support, asked the Johns Hopkins Center for Refugee and Disaster Response to conduct a cholera surge simulation tabletop exercise at these health facilities to improve each facility's response in the event of a cholera surge. Using simulation development guidelines from the Pan American Health Organization and others, a simulation scenario script was produced that included situations of differing severity, supply chain, as well as a surge of patients. A total of 119 hospital staff from seven sites participated in the simulation exercise including community health workers, clinicians, managers, pharmacists, cleaners, and security guards. Clinics that had challenges during the simulated clinical care of patients were those that did not appropriately treat all cholera patients according to protocol, particularly those that were vulnerable, those that would need additional staff to properly treat patients during a surge of cholera, and those that required a better inventory of supplies. Simulation-based activities have the potential to identify healthcare delivery system vulnerabilities that are amenable to intervention prior to a cholera surge.

The weight of a storm: what observations of Earth surface deformation can tell us about Hurricane Harvey

Science.gov (United States)

Borsa, A. A.; Mencin, D.; van Dam, T. M.

2017-12-01

Hurricane Harvey was the first major hurricane to impact the USA in over a decade, making landfall southwest of Houston, TX on August 26, 2017. Although Harvey was downgraded to a tropical storm shortly after landfall, it dropped a record amount of rain and was responsible for epic flooding across much of southeast Texas. While precipitation from a large storm like Harvey can be estimated from in-situ rain gages and Doppler radar, the accompanying surface water changes that lead to flooding are imperfectly observed due to the limited coverage of existing stream and lake level gages and because floodwaters inundate areas that are typically unmonitored. Earth's response to changes in surface loading provides an opportunity to observe the local hydrological response to Hurricane Harvey, specifically the dramatic changes in water storage coincident with and following the storm. Continuous GPS stations in southeastern Texas observed an average drop in land surface elevations of 1.8 cm following Harvey's landfall, followed by a gradual recovery to pre-storm levels over the following month. We interpret this surface motion as Earth's elastic response to the weight of cumulative rainfall during the storm, followed by rebound as that weight was removed by runoff and evapotranspiration (ET). Using observations of surface displacements from GPS stations in the HoustonNET and Plate Boundary Observatory networks, we model the daily water storage changes across Texas and Louisiana associated with Harvey. Because Harvey's barometric pressure low caused surface uplift at the cm level which temporarily obscured the subsidence signal due to precipitation, we model and remove the effect of atmospheric loading from the GPS data prior to our analysis. We also consider the effect on GPS position time series of non-tidal ocean loading due to the hurricane storm surge, which at the coast was an order of magnitude larger than loads due to precipitation alone. Finally, we use our results to

A simulation method for lightning surge response of switching power

International Nuclear Information System (INIS)

Wei, Ming; Chen, Xiang

2013-01-01

In order to meet the need of protection design for lighting surge, a prediction method of lightning electromagnetic pulse (LEMP) response which is based on system identification is presented. Experiments of switching power's surge injection were conducted, and the input and output data were sampled, de-noised and de-trended. In addition, the model of energy coupling transfer function was obtained by system identification method. Simulation results show that the system identification method can predict the surge response of linear circuit well. The method proposed in the paper provided a convenient and effective technology for simulation of lightning effect.

Electromagnetic computation methods for lightning surge protection studies

CERN Document Server

Baba, Yoshihiro

2016-01-01

This book is the first to consolidate current research and to examine the theories of electromagnetic computation methods in relation to lightning surge protection. The authors introduce and compare existing electromagnetic computation methods such as the method of moments (MOM), the partial element equivalent circuit (PEEC), the finite element method (FEM), the transmission-line modeling (TLM) method, and the finite-difference time-domain (FDTD) method. The application of FDTD method to lightning protection studies is a topic that has matured through many practical applications in the past decade, and the authors explain the derivation of Maxwell's equations required by the FDTD, and modeling of various electrical components needed in computing lightning electromagnetic fields and surges with the FDTD method. The book describes the application of FDTD method to current and emerging problems of lightning surge protection of continuously more complex installations, particularly in critical infrastructures of e...

Condition Assessment of Metal Oxide Surge Arrester Based on Multi-Layer SVM Classifier

Directory of Open Access Journals (Sweden)

M Khodsuz

2015-12-01

Full Text Available This paper introduces the indicators for surge arrester condition assessment based on the leakage current analysis. Maximum amplitude of fundamental harmonic of the resistive leakage current, maximum amplitude of third harmonic of the resistive leakage current and maximum amplitude of fundamental harmonic of the capacitive leakage current were used as indicators for surge arrester condition monitoring. Also, the effects of operating voltage fluctuation, third harmonic of voltage, overvoltage and surge arrester aging on these indicators were studied. Then, obtained data are applied to the multi-layer support vector machine for recognizing of surge arrester conditions. Obtained results show that introduced indicators have the high ability for evaluation of surge arrester conditions.

Healthcare4VideoStorm: Making Smart Decisions Based on Storm Metrics.

Science.gov (United States)

Zhang, Weishan; Duan, Pengcheng; Chen, Xiufeng; Lu, Qinghua

2016-04-23

Storm-based stream processing is widely used for real-time large-scale distributed processing. Knowing the run-time status and ensuring performance is critical to providing expected dependability for some applications, e.g., continuous video processing for security surveillance. The existing scheduling strategies' granularity is too coarse to have good performance, and mainly considers network resources without computing resources while scheduling. In this paper, we propose Healthcare4Storm, a framework that finds Storm insights based on Storm metrics to gain knowledge from the health status of an application, finally ending up with smart scheduling decisions. It takes into account both network and computing resources and conducts scheduling at a fine-grained level using tuples instead of topologies. The comprehensive evaluation shows that the proposed framework has good performance and can improve the dependability of the Storm-based applications.

Impact assessment of coastal hazards due to future changes of tropical cyclones in the North Pacific Ocean

Directory of Open Access Journals (Sweden)

Nobuhito Mori

2016-03-01

Full Text Available Tropical cyclones generate severe hazards in the middle latitudes. A brief review and applications of dynamical and statistical downscaling of tropical cyclone (TC are described targeting extreme storm surge and storm wave hazard assessment. First, a review of the current understanding of the changes in the characteristics of TCs in the past and in the future is shown. Then, a review and ongoing research about impact assessment of tropical cyclones both dynamical downscaling and statistical model are described for Typhoon Vera in 1959 and Typhoon Haiyan in 2013. Finally, several examples of impact assessment of storm surge and extreme wave changes are presented. Changes in both TC intensity and track are linked to future changes in extreme storm surge and wave climate in middle latitude.

Hospital-Based Coalition to Improve Regional Surge Capacity

Directory of Open Access Journals (Sweden)

James M. Learning

2012-12-01

Full Text Available Introduction: Surge capacity for optimization of access to hospital beds is a limiting factor in response to catastrophic events. Medical facilities, communication tools, manpower, and resource reserves exist to respond to these events. However, these factors may not be optimally functioning to generate an effective and efficient surge response. The objective was to improve the function of these factors.Methods: Regional healthcare facilities and supporting local emergency response agencies developed a coalition (the Healthcare Facilities Partnership of South Central Pennsylvania; HCFP¬SCPA to increase regional surge capacity and emergency preparedness for healthcare facilities. The coalition focused on 6 objectives: (1 increase awareness of capabilities and assets, (2 develop and pilot test advanced planning and exercising of plans in the region, (3 augment written medical mutual aid agreements, (4 develop and strengthen partnership relationships, (5 ensure National Incident Management System compliance, and (6 develop and test a plan for effective utilization of volunteer healthcare professionals.Results: In comparison to baseline measurements, the coalition improved existing areas covered under all 6 objectives documented during a 24-month evaluation period. Enhanced communications between the hospital coalition, and real-time exercises, were used to provide evidence of improved preparedness for putative mass casualty incidents.Conclusion: The HCFP-SCPA successfully increased preparedness and surge capacity through a partnership of regional healthcare facilities and emergency response agencies.

Aging assessment of surge protective devices in nuclear power plants

International Nuclear Information System (INIS)

Davis, J.F.; Subudhi, M.; Carroll, D.P.

1996-01-01

An assessment was performed to determine the effects of aging on the performance and availability of surge protective devices (SPDs), used in electrical power and control systems in nuclear power plants. Although SPDs have not been classified as safety-related, they are risk-important because they can minimize the initiating event frequencies associated with loss of offsite power and reactor trips. Conversely, their failure due to age might cause some of those initiating events, e.g., through short circuit failure modes, or by allowing deterioration of the safety-related component(s) they are protecting from overvoltages, perhaps preventing a reactor trip, from an open circuit failure mode. From the data evaluated during 1980--1994, it was found that failures of surge arresters and suppressers by short circuits were neither a significant risk nor safety concern, and there were no failures of surge suppressers preventing a reactor trip. Simulations, using the ElectroMagnetic Transients Program (EMTP) were performed to determine the adequacy of high voltage surge arresters

Development of VLF noise storm and its relation to dynamics of magnetosphere during geomagnetic storms

International Nuclear Information System (INIS)

Fedyakina, N.I.; Khorosheva, O.V.

1989-01-01

Dependence between the development of geomagnetic storm and VLF noise storm is studied. Two conditions should be met for the development of noise storm in VLF-hiss (f ≅ 0.5-10 kHz): a) threshold intensity of electron fluxes with E e > 40 keV in plasma layers; b) the presence of substorms resulting to widening of electron belt and its collision with cold plasma of plasmasphere. The noise storm at the fixed longitude begins about midnight independently of the phase of magnetic storm; Noise storm duration is connected with geomagnetic storm intensity by direct linear relationship

Geomagnetic Storm Sudden Commencements

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Storm Sudden Commencements (ssc) 1868 to present: STORM1 and STORM2 Lists: (Some text here is taken from the International Association of Geomagnetism and Aeronomy...

Effect of Hydraulic Accumulator on Pressure Surge of a Hydrostatic Transmission System

Science.gov (United States)

Kumar, Ajit; Das, Jayanta; Dasgupta, Kabir; Barnwal, Manish Kumar

2018-04-01

Hydraulic power system is generally used in off-road vehicles for power transmission such as Heavy Earth Moving Machineries (HEMM). Their energy efficiency and unsubstantial failure becomes an extensive subject of analysis. Various arrangements in the system are compassed along with the utilization of some appropriate components. Application of a hydraulic accumulator is one among them. Benefits of accumulator is its multi-purpose usages like energy saving and pressure surge damping. This paper deals with the control of pressure surges in the hydraulic system and energy saving from the surges by using accumulator. For this purpose, the simulation of the hydraulic system is done in MATLAB/SimulinkR environment and an external disturbance is introduced to generate the pressure surge. The surge absorptivity of the accumulator is studied for different sizes at different pre-charged conditions of the accumulator. The discharge characteristics of different sized accumulators are also analyzed in this paper. It is observed that the ability to absorb the surge and stabilize the system is high in the smaller capacity accumulator. However the energy delivery time of larger sized accumulator is high.

On the contribution of reconstruction labor wages and material prices to demand surge

Science.gov (United States)

Olsen, Anna H.; Porter, Keith A.

2011-01-01

Demand surge is understood to be a socio-economic phenomenon of large-scale natural disasters, most commonly explained by higher repair costs (after a large- versus small-scale disaster) resulting from higher material prices and labor wages. This study tests this explanation by developing quantitative models for the cost change of sets, or "baskets," of repairs to damage caused by Atlantic hurricanes making landfall on the mainland United States. We define six such baskets, representing the total repair cost, and material and labor components, each for a typical residential or commercial property. We collect cost data from the leading provider of these data to insurance claims adjusters in the United States, and we calculate the cost changes from July to January for nine Atlantic hurricane seasons at fifty-two cities on the Atlantic and Gulf Coasts. The data show that: changes in labor costs drive the changes in total repair costs; cost changes can vary significantly by geographic region and year; and cost changes for the residential basket of repairs are more volatile than the cost changes for the commercial basket. We then propose a series of multilevel regression models to predict the cost changes by considering several combinations of the following explanatory variables: the largest gradient wind speed at a city in a hurricane season; the number of tropical storms in a hurricane season whose center passes within 200 km of a city; and cost changes in the first two quarters of the year. We also allow the coefficients of the regression model to be stochastic, varying across groups defined by region of the Southeastern United States and year. Our best models predict that, for any city on the Gulf or Atlantic Coasts in any hurricane season, the residential total repair cost changes vary from 0.01 to 0.25, depending on the wind speed and number of storms, with an uncertainty of 0.1 (two standard errors of prediction) given the wind speed and number of storms. The

Shoreline resilience to individual storms and storm clusters on a meso-macrotidal barred beach

NARCIS (Netherlands)

Angnuureng, Donatus Bapentire; Almar, Rafael; Senechal, Nadia; Castelle, Bruno; Addo, Kwasi Appeaning; Marieu, Vincent; Ranasinghe, Roshanka

2017-01-01

This study investigates the impact of individual storms and storm clusters on shoreline recovery for the meso-to macrotidal, barred Biscarrosse beach in SW France, using 6 years of daily video observations. While the study area experienced 60 storms during the 6-year study period, only 36 storms

The effects of storms and storm-generated currents on sand beaches in Southern Maine, USA

Science.gov (United States)

Hill, H.W.; Kelley, J.T.; Belknap, D.F.; Dickson, S.M.

2004-01-01

Storms are one of the most important controls on the cycle of erosion and accretion on beaches. Current meters placed in shoreface locations of Saco Bay and Wells Embayment, ME, recorded bottom currents during the winter months of 2000 and 2001, while teams of volunteers profiled the topography of nearby beaches. Coupling offshore meteorological and beach profile data made it possible to determine the response of nine beaches in southern Maine to various oceanographic and meteorological conditions. The beaches selected for profiling ranged from pristine to completely developed and permitted further examination of the role of seawalls on the response of beaches to storms. Current meters documented three unique types of storms: frontal passages, southwest storms, and northeast storms. In general, the current meter results indicate that frontal passages and southwest storms were responsible for bringing sediment towards the shore, while northeast storms resulted in a net movement of sediment away from the beach. During the 1999-2000 winter, there were a greater percentage of frontal passages and southwest storms, while during the 2000-2001 winter, there were more northeast storms. The sediment that was transported landward during the 1999-2000 winter was reworked into the berm along moderately and highly developed beaches during the next summer. A northeast storm on March 5-6, 2001, resulted in currents in excess of 1 m s-1 and wave heights that reached six meters. The storm persisted over 10 high tides and caused coastal flooding and property damage. Topographic profiles made before and after the storm demonstrate that developed beaches experienced a loss of sediment volume during the storm, while sediment was redistributed along the profile on moderately developed and undeveloped beaches. Two months after the storm, the profiles along the developed beaches had not reached their pre-storm elevation. In comparison, the moderately developed and undeveloped beaches

Centrifugal Compressor Surge Margin Improved With Diffuser Hub Surface Air Injection

Science.gov (United States)

Skoch, Gary J.

2002-01-01

Aerodynamic stability is an important parameter in the design of compressors for aircraft gas turbine engines. Compression system instabilities can cause compressor surge, which may lead to the loss of an aircraft. As a result, engine designers include a margin of safety between the operating line of the engine and the stability limit line of the compressor. The margin of safety is typically referred to as "surge margin." Achieving the highest possible level of surge margin while meeting design point performance objectives is the goal of the compressor designer. However, performance goals often must be compromised in order to achieve adequate levels of surge margin. Techniques to improve surge margin will permit more aggressive compressor designs. Centrifugal compressor surge margin improvement was demonstrated at the NASA Glenn Research Center by injecting air into the vaned diffuser of a 4:1-pressure-ratio centrifugal compressor. Tests were performed using injector nozzles located on the diffuser hub surface of a vane-island diffuser in the vaneless region between the impeller trailing edge and the diffuser-vane leading edge. The nozzle flow path and discharge shape were designed to produce an air stream that remained tangent to the hub surface as it traveled into the diffuser passage. Injector nozzles were located near the leading edge of 23 of the 24 diffuser vanes. One passage did not contain an injector so that instrumentation located in that passage would be preserved. Several orientations of the injected stream relative to the diffuser vane leading edge were tested over a range of injected flow rates. Only steady flow (nonpulsed) air injection was tested. At 100 percent of the design speed, a 15-percent improvement in the baseline surge margin was achieved with a nozzle orientation that produced a jet that was bisected by the diffuser vane leading edge. Other orientations also improved the baseline surge margin. Tests were conducted at speeds below the

In the Eye of the Storm: A Participatory Course on Coastal Storms

Science.gov (United States)

Curtis, Scott

2013-01-01

Storm disasters are amplified in the coastal environment due to population pressures and the power of the sea. The upper-division/graduate university course "Coastal Storms" was designed to equip future practitioners with the skills necessary to understand, respond to, and mitigate for these natural disasters. To accomplish this, "Coastal Storms"…

Sensitivity of tropical cyclone simulations to microphysics parameterizations in WRF

International Nuclear Information System (INIS)

Reshmi Mohan, P.; Srinivas, C.V.; Bhaskaran, R.; Venkatraman, B.; Yesubabu, V.

2018-01-01

Tropical cyclones (TC) cause storm surge along coastal areas where these storms cross the coast. As major nuclear facilities are usually installed in coastal region, the surge predictions are highly important for DAE. The critical TC parameters needed in estimating storm surge are intensity (winds, central pressure and radius of maximum winds) and storm tracks. The predictions with numerical models are generally made by representing the clouds and precipitation processes using convective and microphysics parameterization. At high spatial resolutions (1-3Km) microphysics can act as cloud resolving NWP model to explicitly resolve the convective precipitation without using convection schemes. Recent simulation studies using WRF on severe weather phenomena such as thunderstorms and hurricanes indicated large sensitivity of predicted rainfall and hurricane tracks to microphysics due to variation in temperature and pressure gradients which generate winds that determine the storm track. In the present study the sensitivity of tropical cyclone tracks and intensity to different microphysics schemes has been conducted

Development of a global river-coastal coupling model and its application to flood simulation in Asian mega-delta regions

Science.gov (United States)

Ikeuchi, Hiroaki; Hirabayashi, Yukiko; Yamazaki, Dai; Muis, Sanne; Ward, Philip; Verlaan, Martin; Winsemius, Hessel; Kanae, Shinjiro

2017-04-01

The world's mega-delta regions and estuaries are susceptible to various water-related disasters, such as river flooding and storm surge. Moreover, simultaneous occurrence of them would be more devastating than a situation where they occur in isolation. Therefore, it is important to provide information about compound risks of fluvial and coastal floods at a large scale, both their statistical dependency as well as their combined resulting flooding in delta regions. Here we report on a first attempt to address this issue globally by developing a method to couple a global river model (CaMa-Flood) and a global tide and surge reanalysis (GTSR) dataset. A state-of-the-art global river routing model, CaMa-Flood, was modified to represent varying sea levels due to tides and storm surges as downstream boundary condition, and the GTSR dataset was post-processed to serve as inputs to the CaMa-Flood river routing simulation and a long-term simulation was performed to incorporate the temporal dependency between coastal tide and surge on the one hand, and discharge on the other. The coupled model was validated against observations, showing better simulation results of water levels in deltaic regions than simulation without GTSR. For example in the Ganges Delta, correlation coefficients were increased by 0.06, and root mean square errors were reduced by 0.22 m. Global coupling simulations revealed that storm surges affected river water levels in coastal regions worldwide, especially in low-lying flat areas with increases in water level larger than 0.5 m. By employing enhanced storm surge simulation with tropical storm tracks, we also applied the model to examine impacts of past hurricane and cyclone storm events on river flood inundation.

Experimental Study on Noise Characteristic of Centrifugal Compressor Surge

OpenAIRE

Yang, Qichao; Zhao, Yuanyang; SHU, Yue; LI, Xiaosa; LI, Liansheng

2016-01-01

The centrifugal air compressor test rig is was designed and established. The experimental study was carried out on the surge characteristics of centrifugal compressor including the pressure in the pipe and the noise characteristics under different rotation speed. The tested results showed that both the suction pressure and discharge pressure fluctuation increase under surge condition and the amplitude of discharge pressure fluctuation is significantly higher than that of suction pressure. In ...

Community And Stakeholder Engagement With A University-Based Storm Research Team And Program During Events: Progressive Awareness, Cooperation And Mutual Support.

Science.gov (United States)

Gayes, P. T.; Bao, S.; Yan, T.; Pietrafesa, L. J.; Hallstrom, J.; Stirling, D.; Mullikin, T.; McClam, M.; Byrd, M.; Aucoin, K.; Marosites, B.

2017-12-01

HUGO: The HUrricane Genesis and Outlook program is a research initiative spanning new approaches to Atlantic tropical season outlooking to a storm event-related interactively coupled model system. In addition to supporting faculty and student academic research it has progressively been engaged by diverse regional interests in the public and private sector. The seasonal outlook incorporates 22 regional-to-global climate drivers developed from the historical storm database and has shown good skill related to historical storm seasons within the development of the model as well as the last several years in an outlook capacity. The event scale model is a based upon a fully interactively coupled model system incorporating ocean, atmosphere, wave and surge/flood models. The recent cluster of storms impacting the Southeast US provided an opportunity to test the model system and helped develop strong collaborative interests across diverse groups seeking to facilitate local capacity and access to additional storm-related information, observations and expertise. The SC State Guard has actively engaged the HUGO team in carrying out their charge in emergency responders planning and activities during several recent storms and flooding events. They were instrumental in developing support to expand observational systems aiding model validation and development as well as develop access pathways for deployment of new observational technology developed through NSF sponsored projects (Intelligent River and Hurricane-RAPID) with ISENSE at Florida Atlantic University to advance observational capability and density especially during or immediately following events. At the same time an increasing number of county-level emergency and environmental managers and private sector interests have similarly been working collaborately towards expanding observational systems contributing to the goals of the growing storm-oriented cooperative and as well as broader national MesoUS goals. Collectively

Nippon Storm Study design

Directory of Open Access Journals (Sweden)

Takashi Kurita

2012-10-01

Full Text Available An understanding of the clinical aspects of electrical storm (E-storms in patients with implantable cardiac shock devices (ICSDs: ICDs or cardiac resynchronization therapy with defibrillator [CRT-D] may provide important information for clinical management of patients with ICSDs. The Nippon Storm Study was organized by the Japanese Heart Rhythm Society (JHRS and Japanese Society of Electrocardiology and was designed to prospectively collect a variety of data from patients with ICSDs, with a focus on the incidence of E-storms and clinical conditions for the occurrence of an E-storm. Forty main ICSD centers in Japan are participating in the present study. From 2002, the JHRS began to collect ICSD patient data using website registration (termed Japanese cardiac defibrillator therapy registration, or JCDTR. This investigation aims to collect data on and investigate the general parameters of patients with ICSDs, such as clinical backgrounds of the patients, purposes of implantation, complications during the implantation procedure, and incidence of appropriate and inappropriate therapies from the ICSD. The Nippon Storm Study was planned as a sub-study of the JCDTR with focus on E-storms. We aim to achieve registration of more than 1000 ICSD patients and complete follow-up data collection, with the assumption of a 5–10% incidence of E-storms during the 2-year follow-up.

Effect of switching surges on ehv system design

Energy Technology Data Exchange (ETDEWEB)

Baril, G A; McGillis, D

1966-01-01

The presence of switching surges imposes certain conditions on the design of ehv system and certain resulting requirements in the basic components of these systems. At extra high voltage, it becomes both a practical as well as an economic necessity to limit the magnitude of switching surge overvoltages. This can be accomplished by the installation of suitable terminal equipment, and for the 735 kV system it was found necessary to install permanently connected shunt reactors on the transmission lines and to provide for the installation of closing resistors on the circuit breakers.

Biological effects of geomagnetic storms

International Nuclear Information System (INIS)

Chibisov, S.M.; Breus, T.K.; Levitin, A.E.; Drogova, G.M.; AN SSSR, Moscow; AN SSSR, Moscow

1995-01-01

Six physiological parameters of cardio-vascular system of rabbits and ultrastructure of cardiomyocytes were investigated during two planetary geomagnetic storms. At the initial and main phase of the storm the normal circadian structure in each cardiovascular parameter was lost. The disynchronozis was growing together with the storm and abrupt drop of cardia activity was observed during the main phase of storm. The main phase of storm followed by the destruction and degradation of cardiomyocytes. Parameters of cardia activity became substantially synchronized and characterized by circadian rhythm structure while the amplitude of deviations was still significant at the recovery stage of geomagnetic storm. 3 refs.; 7 figs

Assessment of water pipes durability under pressure surge

Science.gov (United States)

Pham Ha, Hai; Minh, Lanh Pham Thi; Tang Van, Lam; Bulgakov, Boris; Bazhenova, Soafia

2017-10-01

Surge phenomenon occurs on the pipeline by the closing valve or pump suddenly lost power. Due to the complexity of the water hammer simulation, previous researches have only considered water hammer on the single pipe or calculation of some positions on water pipe network, it have not been analysis for all of pipe on the water distribution systems. Simulation of water hammer due to closing valve on water distribution system and the influence level of pressure surge is evaluated at the defects on pipe. Water hammer on water supply pipe network are simulated by Water HAMMER software academic version and the capacity of defects are calculated by SINTAP. SINTAP developed from Brite-Euram projects in Brussels-Belgium with the aim to develop a process for assessing the integrity of the structure for the European industry. Based on the principle of mechanical fault, indicating the size of defects in materials affect the load capacity of the product in the course of work, the process has proposed setting up the diagram to fatigue assessment defect (FAD). The methods are applied for water pipe networks of Lien Chieu district, Da Nang city, Viet Nam, the results show the affected area of wave pressure by closing the valve and thereby assess the greatest pressure surge effect to corroded pipe. The SINTAP standard and finite element mesh analysis at the defect during the occurrence of pressure surge which will accurately assess the bearing capacity of the old pipes. This is one of the bases to predict the leakage locations on the water distribution systems. Amount of water hammer when identified on the water supply networks are decreasing due to local losses at the nodes as well as the friction with pipe wall, so this paper adequately simulate water hammer phenomena applying for actual water distribution systems. The research verified that pipe wall with defect is damaged under the pressure surge value.

Characteristics and possibilities of software tool for metal-oxide surge arresters selection

Directory of Open Access Journals (Sweden)

Đorđević Dragan

2012-01-01

Full Text Available This paper presents a procedure for the selection of metal-oxide surge arresters based on the instructions given in the Siemens and ABB catalogues, respecting their differences and the characteristics and possibilities of the software tool. The software tool was developed during the preparation of a Master's thesis titled, 'Automation of Metal-Oxide Surge Arresters Selection'. An example is presented of the selection of metal-oxide surge arresters using the developed software tool.

Influence of Surge on Extreme Roll Amplitudes

DEFF Research Database (Denmark)

Vidic-Perunovic, Jelena; Rognebakke, Olav; Pedersen, Preben Terndrup

2008-01-01

Interference of the wave-induced ship surge motion with roll dynamics has been studied. The surge motion has been included in a previously derived hydrodynamic roll prediction model in order to account for the ship speed variation due to the longitudinal incident wave pressure force. Depending...... balanced in order to determine the added thrust term that would represent actions to maintain speed The resulting forward speed variation affects the frequency of encounter and the parametric roll resonant condition is directly influenced by this speed variation. The analysis procedure is demonstrated...... for an example containership sailing mainly in head sea condition and higher sea states. Sensitivity of the results to the added thrust model and vertical motion calculation is discussed....

Fluid-structure interaction analysis for pressurizer surge line subjected to thermal stratification

International Nuclear Information System (INIS)

Kang, Dong Gu; Jhung, Myung Jo; Chang, Soon Heung

2011-01-01

Research highlights: → Temperature of surge line due to stratified flow is defined using CFD analysis. → Fluid-structure interaction analysis is performed to investigate the response characteristics due to thermal stress. → Fatigue usage factors due to thermal stratification are relatively low. → Simplifying temperature distribution in surge line is not always conservative. - Abstract: Serious mechanical damages such as cracks and plastic deformations due to excessive thermal stress caused by thermal stratification have been experienced in several nuclear power plants. In particular, the thermal stratification in the pressurizer surge line has been addressed as one of the significant safety and technical issues. In this study, a detailed unsteady computational fluid dynamics (CFD) analysis involving conjugate heat transfer analysis is performed to obtain the transient temperature distributions in the wall of the pressurizer surge line subjected to stratified internal flows either during out-surge or in-surge operation. The thermal loads from CFD calculations are transferred to the structural analysis code which is employed for the thermal stress analysis to investigate the response characteristics, and the fatigue analysis is ultimately performed. In addition, the thermal stress and fatigue analysis results obtained by applying the realistic temperature distributions from CFD calculations are compared with those by assuming the simplified temperature distributions to identify some requirements for a realistic and conservative thermal stress analysis from a safety point of view.

Quantification of Sediment Transport During Glacier Surges and its Impact on Landform Architecture

DEFF Research Database (Denmark)

Kjær, Kurt H.; Schomacker, Anders; Korsgaard, Niels Jákup

) for 1945, prior to the last surge in 1964, and for 2003 in order to assess the effect of the surge on the sediment architecture in the forefield. The pre- and post-surge DEMs allow direct quantification of the sediment volumes that were re-distributed in the forefield by the surging ice mass in 1964...... or glaciofluvial outwash fans. Mapping of the sediment thickness in the glacier forefield shows higher accumulation along ice marginal positions related to wedge formation during extremely rapid ice flow. Fast flow was sustained by overpressurized water causing sediment-bedrock decoupling beneath a thick sediment...... architecture occurs distal to the 1810 ice margin, where the 1890 surge advanced over hitherto undeformed sediments. Proximal to the 1810 ice margin, the landscape have been transgressed by either one or two glaciers (in 1890 and 1964). The most complex landscape architecture is found proximal to the 1964 ice...

MAGNETIC-RECONNECTION GENERATED SHOCK WAVES AS A DRIVER OF SOLAR SURGES

International Nuclear Information System (INIS)

Yang, Heesu; Chae, Jongchul; Park, Hyungmin; Song, Dong-uk; Cho, Kyuhyoun; Lim, Eun-Kyung; Lee, Kyoung-sun

2014-01-01

We found that a surge consists of multiple shock features. In our high-spatiotemporal spectroscopic observation of the surge, each shock is identified with the sudden appearance of an absorption feature at the blue wings of the Ca II 8542 Å line and Hα line that gradually shifts to the red wings. The shock features overlap with one another with the time interval of 110 s, which is much shorter than the duration of each shock feature, 300-400 s. This finding suggests that the multiple shocks might not have originated from a train of sinusoidal waves generated by oscillations and flows in the photosphere. As we found the signature of the magnetic flux cancelations at the base of the surge, we conclude that the multiple shock waves in charge of the surge were generated by the magnetic reconnection that occurred in the low atmosphere in association with the flux cancelation

IRI STORM validation over Europe

Science.gov (United States)

Haralambous, Haris; Vryonides, Photos; Demetrescu, Crişan; Dobrică, Venera; Maris, Georgeta; Ionescu, Diana

2014-05-01

The International Reference Ionosphere (IRI) model includes an empirical Storm-Time Ionospheric Correction Model (STORM) extension to account for storm-time changes of the F layer peak electron density (NmF2) during increased geomagnetic activity. This model extension is driven by past history values of the geomagnetic index ap (The magnetic index applied is the integral of ap over the previous 33 hours with a weighting function deduced from physically based modeling) and it adjusts the quiet-time F layer peak electron density (NmF2) to account for storm-time changes in the ionosphere. In this investigation manually scaled hourly values of NmF2 measured during the main and recovery phases of selected storms for the maximum solar activity period of the current solar cycle are compared with the predicted IRI-2012 NmF2 over European ionospheric stations using the STORM model option. Based on the comparison a subsequent performance evaluation of the STORM option during this period is quantified.

Lightning Evolution In Two North Central Florida Summer Multicell Storms and Three Winter/Spring Frontal Storms

Science.gov (United States)

Caicedo, J. A.; Uman, M. A.; Pilkey, J. T.

2018-01-01

We present the first lightning evolution studies, via the Lightning Mapping Array (LMA) and radar, performed in North Central Florida. Parts of three winter/spring frontal storms (cold season) and two complete summer (warm season) multicell storms are studied. Storm parameters measured are as follows: total number of flashes, flash-type classification, first flashes, flash initiation altitude, flash initiation power, flash rate (flashes per minute), charge structure, altitude and temperature ranges of the inferred charge regions, atmospheric isotherm altitude, radar base reflectivity (dBZ), and radar echo tops (EET). Several differences were found between summer multicell and winter/spring frontal storms in North Central Florida: (1) in winter/spring storms, the range of altitudes that all charge regions occupy is up to 1 km lower in altitude than in summer storms, as are the 0°C, -10°C, and -20°C isotherms; (2) lightning activity in summer storms is highly correlated with changes in radar signatures, in particular, echo tops; and (3) the LMA average initiation power of all flash types in winter/frontal storms is about an order of magnitude larger than that for summer storms. In relation to storms in other geographical locations, North Central Florida seasonal storms were found to have similarities in most parameters studied with a few differences, examples in Florida being (1) colder initiation altitudes for intracloud flashes, (2) charge regions occupying larger ranges of atmospheric temperatures, and (3) winter/spring frontal storms not having much lightning activity in the stratiform region.

A new on-line leakage current monitoring system of ZnO surge arresters

International Nuclear Information System (INIS)

Lee, Bok-Hee; Kang, Sung-Man

2005-01-01

This paper presents a new on-line leakage current monitoring system of zinc oxide (ZnO) surge arresters. To effectively diagnose the deterioration of ZnO surge arresters, a new algorithm and on-line leakage current detection device, which uses the time-delay addition method, for discriminating the resistive and capacitive currents was developed to use in the aging test and durability evaluation for ZnO arrester blocks. A computer-based measurement system of the resistive leakage current, the on-line monitoring device can detect accurately the leakage currents flowing through ZnO surge arresters for power frequency ac applied voltages. The proposed on-line leakage current monitoring device of ZnO surge arresters is more highly sensitive and gives more linear response than the existing devices using the detection method of the third harmonic leakage currents. Therefore, the proposed leakage current monitoring device can be useful for predicting the defects and performance deterioration of ZnO surge arresters in power system applications

Planning for partnerships: Maximizing surge capacity resources through service learning.

Science.gov (United States)

Adams, Lavonne M; Reams, Paula K; Canclini, Sharon B

2015-01-01

Infectious disease outbreaks and natural or human-caused disasters can strain the community's surge capacity through sudden demand on healthcare activities. Collaborative partnerships between communities and schools of nursing have the potential to maximize resource availability to meet community needs following a disaster. This article explores how communities can work with schools of nursing to enhance surge capacity through systems thinking, integrated planning, and cooperative efforts.

[Analysis of articles published in Chin J Surg since founded in 1951].

Science.gov (United States)

Xia, Shuang; Li, Jing

2016-01-01

To discuss the characteristics of the articles published in Chin J Surg from 1951 to 2015. The journals and articles of Acad Surg from 1951 to 1952 and Chin J Surg from 1953 to 2015 were analyzed. The subjects, foundation, basic medical study, international cooperation of the articles were recorded. In 65 years, there were 20 090 academic articles published in Chin J Surg. The proportions of general surgery, orthopedic surgery, thoracocardiac surgery, urology surgery and neurosurgery articles were 34.08%, 17.96%, 13.09%, 11.91% and 5.85%, respectively. There were 14.83% (1 728/11 653) articles receiving foundation, and 9.42% (1 817/19 290) articles reporting basic medical study. There were 14.8% articles from international authors and 119 articles with international cooperation. From 2000 to 2003, 29 articles in original English were published. The coverage of Chin J Surg contains all the fields of surgery. It tends to publish the studies focus on clinical issues.Through reinforcing the content plan and optimizing the show form, the more Chinese surgical research achievements could be shared by the surgeons worldwide.

The insulation coordination and surge arrester design for HTS cable system in Icheon substation

Energy Technology Data Exchange (ETDEWEB)

Lee, Hansang, E-mail: Hansang80@korea.ac.kr [School of Railway and Electrical Engineering, Kyungil University, Hayang-eup, Gyeongsan-si, Gyeongsangbuk-do 712-701 (Korea, Republic of); Yoon, Dong-Hee [Department of New and Renewable Energy, Kyungil University, Hayang-eup, Gyeongsan-si, Gyeongsangbuk-do 712-701 (Korea, Republic of); Lee, Seung-Ryul [Korea Electrotechnology Research Institute, Naeson-dong, Uiwang-si, Gyeonggi-do 437-080 (Korea, Republic of); Yang, Byeong-Mo [Korea Electric Power Research Institute, Munji-dong, Yuseong-gu, Daejeon 305-760 (Korea, Republic of); Jang, Gilsoo, E-mail: gjang@korea.ac.kr [School of Electrical Engineering, Korea University, Anam-dong 5-ga, Seongbuk-gu, Seoul 136-713 (Korea, Republic of)

2013-01-15

Highlights: ► It is necessary to study lightning response of the HTS cable. ► The analytic model has been developed for the HTS cable in the Icheon substation. ► Well-designed surge arrester has been verified through PSCAD/EMTDC simulations. -- Abstract: This paper proposes an insulation coordination and surge arrester design for HTS (High-Temperature Superconducting) cable system in Icheon substation in Korea. In the aspect of the economic analysis, since the HTS cable is very expensive, the insulation coordination to prevent the dielectric breakdown caused by the lightning surge should be considered carefully. Also, in the aspect of the power system reliability, since the HTS cable has much more capacity compared than conventional power cables and the ripple effect from the HTS cable failure may lead to the wide area blackout, an intensive study for insulation coordination from lightning surge is one of the most important considerations. In this paper, the insulation coordination for lightning surge is verified using HTS cable and power equipment models and the design of the proper surge arrester is proposed.

[Diagnosis and treatment of thyroid storm].

Science.gov (United States)

Akamizu, Takashi

2012-11-01

Thyrotoxic storm is a life-threatening condition requiring emergency treatment. Neither its epidemiological data nor diagnostic criteria have been fully established. We clarified the clinical and epidemiological characteristics of thyroid storm using nationwide surveys and then formulate diagnostic criteria for thyroid storm. To perform the nationwide survey on thyroid storm, we first developed tentative diagnostic criteria for thyroid storm, mainly based upon the literature (the first edition). We analyzed the relationship of the major features of thyroid storm to mortality and to certain other features. Finally, based upon the findings of these surveys, we revised the diagnostic criteria. Thyrotoxic storm is still a life-threatening disorder with over 10% mortality in Japan.

Assessing extreme sea levels due to tropical cyclones in the Atlantic basin

Science.gov (United States)

Muis, Sanne; Lin, Ning; Verlaan, Martin; Winsemius, Hessel; Vatvani, Deepak; Ward, Philip; Aerts, Jeroen

2017-04-01

Tropical cyclones (TCs), including hurricanes and typhoons, are characterised by high wind speeds and low pressure and cause dangerous storm surges in coastal areas. Over the last 50 years, storm surge incidents in the Atlantic accounted for more than 1,000 deaths in the United Stated. Recent flooding disasters, such as Hurricane Katrina in New Orleans in 2005 and, Hurricane Sandy in New York in 2012, exemplify the significant TC surge risk in the United States. In this contribution, we build on Muis et al. (2016), and present a new modelling framework to simulate TC storm surges and estimate their probabilities for the Atlantic basin. In our framework we simulate the surge levels by forcing the Global Tide and Surge Model (GTSM) with wind and pressure fields from TC events. To test the method, we apply it to historical storms that occurred between 1988 and 2015 in the Atlantic Basin. We obtain high-resolution meteorological forcing by applying a parametric hurricane model (Holland 1980; Lin and Chavas 2012) to the TC extended track data set (Demuth et al. 2006; updated), which describes the position, intensity and size of the historical TCs. Preliminary results show that this framework is capable of accurately reproducing the main surge characteristics during past events, including Sandy and Katrina. While the resolution of GTSM is limited for local areas with a complex bathymetry, the overall performance of the model is satisfactory for the basin-scale application. For an accurate assessment of risk to coastal flooding in the Atlantic basin it is essential to provide reliable estimates of surge probabilities. However, the length of observed TC tracks is too short to accurately estimate the probabilities of extreme TC events. So next steps are to statistically extend the observed record to many thousands of years (e.g., Emanuel et al. 2006), in order to force GTSM with a large number of synthetic storms. Based on these synthetic simulations, we would be able to

Influence of storm characteristics on soil erosion and storm runoff

Science.gov (United States)

Johnny M. III Grace

2008-01-01

Unpaved forest roads can be major sources of sediment from forested watersheds. Storm runoff from forest roads are a concern due to their potential delivery of sediments and nutrients to stream systems resulting in degraded water quality. The volume and sediment concentrations of stormwater runoff emanating from forest roads can be greatly influenced by storm...

Thermospheric storms and related ionospheric effects

International Nuclear Information System (INIS)

Chandra, S.; Spencer, N.W.

1976-01-01

A comparative study of thermospheric storms for the equinox and winter conditions is presented based on the neutral composition measurements from the Aeros-A Nate (Neutral Atmosphere Temperature Experiment) experiment. The main features of the two storms as inferred from the changes in N 2 , Ar, He, and O are described, and their implications to current theories of thermospheric storms are discussed. On the basis of the study of the F region critical frequency measured from a chain of ground-based ionospheric stations during the two storm periods, the general characteristics of the ionospheric storms and the traveling ionospheric disturbances are described. It is suggested that the positive and negative phases of ionospheric storms are the various manifestations of thermospheric storms

Increased level of morning surge in blood pressure in normotensives: A cross-sectional study from Pakistan

International Nuclear Information System (INIS)

Almas, A.; Sultan, F. T.; Kazmi, K.

2016-01-01

Objective: To determine the mean morning surge (MS) in blood pressure, the frequency of increased morning surge in normotensive subjects, and to compare those with morning surge with those without MS. Study Design: A cross-sectional, comparative study. Place and Duration of Study: The Department of Medicine, The Aga Khan University Hospital, Karachi, from April 2011 to March 2012. Methodology: Adult normotensive healthy volunteers aged 35 to 65 years were inducted. Their ambulatory blood pressure (ABP) was measured over a 24-hour period, using digital ambulatory blood pressure monitors. Morning surge was calculated as the average of four readings after waking minus the lowest three nocturnal readings. Increased morning surge was defined as > 11 mm Hg in systolic (SBP) or > 12 mm Hg in diastolic (DBP). Dipping was defined as > 10% dipping in blood pressure. Results: Eighty-two healthy volunteers were recruited. Their mean age was 36.9 ± 1.2 years; 74.4 (61%) were men, and 58.5 (48%) woke up for morning prayers. Mean overall SBP was 113 ± 1.6 mm Hg, overall DBP was 73.9 ± 0.7 mm Hg, and overall heart rate was 75 (10) beats/minute. Mean morning surge was 17.6 ± 1.0 mm Hg in SBP and 16.0 ± 0.8 mm Hg in DBP. The frequency of increased morning surge was 66 (80.5%) in SBP, and 57 (69%) in DBP. On comparison of participants with normal morning surge and increased morning surge in SBP, there was a significant difference in non-dipping status (13.4% in normal vs. 18.3% in increased morning surge, p= 0.001). Conclusion: Mean morning surge in SBP and DBP are relatively higher in this subset population in a tertiary care center in Pakistan. These values are higher than those reported in the literature. (author)

SLR-induced changes on storm flooding in coastal areas: the role of accommodation space

Science.gov (United States)

Jiménez, Jose A.; Dockx, Stijn; Monbaliu, Jaak

2015-04-01

Most of existing predictions of climate-induce changes in coastal storminess in the Mediterranean indicate the absence of any significant increasing trend in neither wave height nor surge. However, this does not mean that magnitude and/or frequency of storm-induced coastal hazards will not be affected by climate change. Thus, sea level rise will induce a series of long-term changes in coastal areas that although not directly affecting storminess will interact with storm-induced processes and, thus, changing coastal storm risks. A typical approach to account SLR-induced effects on coastal inundation by storms is to modify present water level extreme climate by adding expected MWL increase. This implies to consider the coast as a static and passive system to SLR maintaining its configuration from actual to projected (rised) sea level and, as a result of this, the frequency of flood events should increase and, the magnitude of flooding associated to a probability of occurrence will also increase. This will only be realistic for really passive or rigid coasts. However, sandy coastlines will response to SLR and, thus, this approach should undervalue coastal resilience. Within this context, the main aim of this work is to propose a method to assess the effects of SLR on the magnitude of storm-induced coastal flooding on sandy coastlines taking into account their capacity of response. It combines the use of a inundation model (LISFLOOD-FP) for delineating the flood-prone area for given storm conditions and, a coastal module to account for SLR-induced changes in the coastal fringe. The method assumes an equilibrium-type coastal response to SLR which, ideally, implies that the beach profile will be reconstructed under the new higher water level, in such a way that the relative beach configuration will be the same. However, this should only be possible provided there is enough accommodation space in the hinterland. In most of developed coasts, the existence of human built

Outer Continental Shelf Environmental Assessment Program. Final reports of principal investigators. Volume 74

International Nuclear Information System (INIS)

1991-10-01

The volume contains: synthesis of seismicity studies for western Alaska; bottom and near-bottom sediment dynamics in Norton Sound; integration of circulation data in the Beaufort Sea; numerical modeling of storm surges in the Beaufort and Chukchi Seas; numerical modeling of storm surges in Norton Sound; Yukon delta oceanography and meteorology; and superstructure icing and wave hindcast statistics in the Navarin and St. George Basin areas

Progression of the 2011-2012 Surge of Bering Glacier and Bagley Ice Field, Alaska

Science.gov (United States)

Herzfeld, U. C.; McDonald, B.; Stachura, M.; Hale, R.; Trantow, T.; Weltman, A.; Chen, P.

2012-12-01

Bering Glacier, Alaska, started a surge in late spring 2011. The surge reached the ice front in May 2011 and extended into Bagley Ice Field by summer 2011. New surge-related crevassing was observed in July 2012. We collected aerial observations, including systematic videographic and photographic imagery, GPS data and laser altimeter data in September 2011 and in July 2012. In this talk, an analysis of surge progression and comparison to the early, mature and late stages of the 1993-1995 surge of Bering Glacier and Bagley Ice Field will be presented. A suite of approaches will be used to this end: Analysis of elevation changes based on CryoSat data, 2009 and 2010 IceBridge data and 2011 and 2012 laser altimeter data collected by our group, geostatistical classification of crevasse types based on imagery, classification of laser altimeter data and analysis of high-resolution satellite imagery (Worldview and GEOS).

Predicting Impacts of tropical cyclones and sea-Level rise on beach mouse habitat

Science.gov (United States)

Chen, Qin; Wang, Hongqing; Wang, Lixia; Tawes, Robert; Rollman, Drew

2014-01-01

Alabama beach mouse (ABM) (Peromyscus polionotus ammobates) is an important component of the coastal dune ecosystem along the Gulf of Mexico. Due to habitat loss and degradation, ABM is federally listed as an endangered species. In this study, we examined the impacts of storm surge and wind waves, which are induced by hurricanes and sea-level rise (SLR), on the ABM habitat on Fort Morgan Peninsula, Alabama, using advanced storm surge and wind wave models and spatial analysis tools in geographic information systems (GIS). Statistical analyses of the long-term historical data enabled us to predict the extreme values of winds, wind waves, and water levels in the study area at different return periods. We developed a series of nested domains for both wave and surge modeling and validated the models using field observations of surge hydrographs and high watermarks of Hurricane Ivan (2004). We then developed wave atlases and flood maps corresponding to the extreme wind, surge and waves without SLR and with a 0.5 m of SLR by coupling the wave and surge prediction models. The flood maps were then merged with a map of ABM habitat to determine the extent and location of habitat impacted by the 100-year storm with and without SLR. Simulation results indicate that more than 82% of ABM habitat would be inundated in such an extreme storm event, especially under SLR, making ABM populations more vulnerable to future storm damage. These results have aided biologists, community planners, and other stakeholders in the identification, restoration and protection of key beach mouse habitat in Alabama. Methods outlined in this paper could also be used to assist in the conservation and recovery of imperiled coastal species elsewhere.

Substorms during different storm phases

Directory of Open Access Journals (Sweden)

N. Partamies

2011-11-01

Full Text Available After the deep solar minimum at the end of the solar cycle 23, a small magnetic storm occurred on 20–26 January 2010. The Dst (disturbance storm time index reached the minimum of −38 nT on 20 January and the prolonged recovery that followed the main phase that lasted for about 6 days. In this study, we concentrate on three substorms that took place (1 just prior to the storm, (2 during the main phase of the storm, and (3 at the end of the recovery of the storm. We analyse the solar wind conditions from the solar wind monitoring spacecraft, the duration and intensity of the substorm events as well as the behaviour of the electrojet currents from the ground magnetometer measurements. We compare the precipitation characteristics of the three substorms. The results show that the F-region electron density enhancements and dominant green and red auroral emission of the substorm activity during the storm recovery resembles average isolated substorm precipitation. However, the energy dissipated, even at the very end of a prolonged storm recovery, is very large compared to the typical energy content of isolated substorms. In the case studied here, the dissipation of the excess energy is observed over a 3-h long period of several consecutive substorm intensifications. Our findings suggest that the substorm energy dissipation varies between the storm phases.

Analysis of Hurricane Irene’s Wind Field Using the Advanced Research Weather Research and Forecast (WRF-ARW Model

Directory of Open Access Journals (Sweden)

Alfred M. Klausmann

2014-01-01

Full Text Available Hurricane Irene caused widespread and significant impacts along the U.S. east coast during 27–29 August 2011. During this period, the storm moved across eastern North Carolina and then tracked northward crossing into Long Island and western New England. Impacts included severe flooding from the mid-Atlantic states into eastern New York and western New England, widespread wind damage and power outages across a large portion of southern and central New England, and a major storm surge along portions of the Long Island coast. The objective of this study was to conduct retrospective simulations using the Advanced Research Weather Research and Forecast (WRF-ARW model in an effort to reconstruct the storm’s surface wind field during the period of 27–29 August 2011. The goal was to evaluate how to use the WRF modeling system as a tool for reconstructing the surface wind field from historical storm events to support storm surge studies. The results suggest that, with even modest data assimilation applied to these simulations, the model was able to resolve the detailed structure of the storm, the storm track, and the spatial surface wind field pattern very well. The WRF model shows real potential for being used as a tool to analyze historical storm events to support storm surge studies.

Thromboembolic complications of thyroid storm.

Science.gov (United States)

Min, T; Benjamin, S; Cozma, L

2014-01-01

Thyroid storm is a rare but potentially life-threatening complication of hyperthyroidism. Early recognition and prompt treatment are essential. Atrial fibrillation can occur in up to 40% of patients with thyroid storm. Studies have shown that hyperthyroidism increases the risk of thromboembolic events. There is no consensus with regard to the initiation of anticoagulation for atrial fibrillation in severe thyrotoxicosis. Anticoagulation is not routinely initiated if the risk is low on a CHADS2 score; however, this should be considered in patients with thyroid storm or severe thyrotoxicosis with impending storm irrespective of the CHADS2 risk, as it appears to increase the risk of thromboembolic episodes. Herein, we describe a case of thyroid storm complicated by massive pulmonary embolism. Diagnosis of thyroid storm is based on clinical findings. Early recognition and prompt treatment could lead to a favourable outcome.Hypercoagulable state is a recognised complication of thyrotoxicosis.Atrial fibrillation is strongly associated with hyperthyroidism and thyroid storm.Anticoagulation should be considered for patients with severe thyrotoxicosis and atrial fibrillation irrespective of the CHADS2 score.Patients with severe thyrotoxicosis and clinical evidence of thrombosis should be immediately anticoagulated until hyperthyroidism is under control.

Sedimentology and economic potential of a storm-derived heavy-mineral deposit in the Witteberg group, Cape Province

Energy Technology Data Exchange (ETDEWEB)

Cole, D I; Labuschagne, L S

1982-06-01

Two heavy-mineral-bearing, very fine-grained sandstone beds occur in the upper part of the Weltevrede Formation of the Witteberg Group, 35 km east-north-east of Willowmore, Cape Province. The beds are located within a 10-m-thick stratigraphic interval approximately 100 m below the base of the Witpoort Formation. The beds are amalgamated and consist of up to 5 units, each representing deposition from a storm-surge ebb current. Nine samples taken from the upper bed and one from the lower were analysed for heavy-mineral content. In order of decreasing abundance the heavy-minerals are rutile, zircon, ilmenite, magnetite, monazite, staurolite and sphene. The zircon contains uranium and the monazite is thorium bearing. Simple linear regression analysis of three elements, three oxides, the heavy mineral fraction and the radiometric response indicate that the proportion of heavy minerals does not vary significantly between samples and that the radiometric response of the beds (determined with a portable gamma-ray scintillometer) is directly related to the heavy mineral content. The heavy minerals are concentrated in the upper 20 cm of each bed where deposition from suspension, during the final phase of storm activity, was predominant. Significant concentrations are limited to the upper bed.

Sedimentology and economic potential of a storm-derived heavy-mineral deposit in the Witteberg group, Cape Province

International Nuclear Information System (INIS)

Cole, D.I.; Labuschagne, L.S.

1982-06-01

Two heavy-mineral-bearing, very fine-grained sandstone beds occur in the upper part of the Weltevrede Formation of the Witteberg Group, 35 km east-north-east of Willowmore, Cape Province. The beds are located within a 10-m-thick stratigraphic interval approximately 100 m below the base of the Witpoort Formation. The beds are amalgamated and consist of up to 5 units, each representing deposition from a storm-surge ebb current. Nine samples taken from the upper bed and one from the lower were analysed for heavy-mineral content. In order of decreasing abundance the heavy-minerals are rutile, zircon, ilmenite, magnetite, monazite, staurolite and sphene. The zircon contains uranium and the monazite is thorium bearing. Simple linear regression analysis of three elements, three oxides, the heavy mineral fraction and the radiometric response indicate that the proportion of heavy minerals does not vary significantly between samples and that the radiometric response of the beds (determined with a portable gamma-ray scintillometer) is directly related to the heavy mineral content. The heavy minerals are concentrated in the upper 20 cm of each bed where deposition from suspension, during the final phase of storm activity, was predominant. Significant concentrations are limited to the upper bed

Perfect storm: Therapeutic plasma exchange for a patient with thyroid storm.

Science.gov (United States)

McGonigle, Andrea M; Tobian, Aaron A R; Zink, Jennifer L; King, Karen E

2018-02-01

Thyroid storm is a potentially lethal complication of hyperthyroidism with increased thyroid hormones and exaggerated symptoms of thyrotoxicosis. First-line therapy includes methimazole (MMI) or propylthiouracil (PTU) to block production of thyroid hormones as a bridge toward definitive surgical treatment. Untreated thyroid storm has a mortality rate of up to 30%; this is particularly alarming when patients cannot tolerate or fail pharmacotherapy, especially if they cannot undergo thyroidectomy. Therapeutic plasma exchange (TPE) is an ASFA category III indication for thyroid storm, meaning the optimum role of this therapy is not established, and there are a limited number of cases in the literature. Yet TPE can remove T3 and T4 bound to albumin, autoantibodies, catecholamines and cytokines and is likely beneficial for these patients. We report a patient with thyroid storm who could not tolerate PTU, subsequently failed therapy with MMI, and was not appropriate for thyroidectomy. TPE was therefore performed daily for 4 days (1.0 plasma volume with 5% albumin replacement and 2 U of plasma). Over the treatment course, the patient's thyroid hormones normalized and symptoms of thyroid storm largely resolved; his T3 decreased from 2.27 to 0.81 ng/mL (normal 0.8-2.0), T4 decreased from 4.8 to 1.7 ng/mL (0.8-1.8), heart rate normalized, altered mental status improved, and he converted to normal sinus rhythm. He was ultimately discharged in euthyroid state. He experienced no side effects from his TPE procedures. TPE is a safe and effective treatment for thyroid storm when conventional treatments are not successful or appropriate. © 2017 Wiley Periodicals, Inc.

Magnetic Storms at Mars and Earth

DEFF Research Database (Denmark)

Vennerstrøm, Susanne; Falkenberg, Thea Vilstrup

In analogy with magnetic storms at the Earth, periods of significantly enhanced global magnetic activity also exist at Mars. The extensive database of magnetic measurements from Mars Global Surveyor (MGS), covering almost an entire solar cycle, is used in combination with geomagnetic activity...... indices at Earth to compare the occurrence of magnetic storms at Mars and Earth. Based on superposed epochs analysis the time-development of typical magnetic storms at Mars and Earth is described. In contradiction to storms at Earth, most magnetic storms at Mars are found to be associated...... with heliospheric current sheet crossings, where the IMF changes polarity. While most storms at the Earth occur due to significant southward excursions of the IMF associated with CMEs, at Mars most storms seem to be associated with the density enhancement of the heliospheric current sheet. Density enhancements...

Black Swan Tropical Cyclones

Science.gov (United States)

Emanuel, K.; Lin, N.

2012-12-01

Virtually all assessments of tropical cyclone risk are based on historical records, which are limited to a few hundred years at most. Yet stronger TCs may occur in the future and at places that have not been affected historically. Such events lie outside the realm of historically based expectations and may have extreme impacts. Their occurrences are also often made explainable after the fact (e.g., Hurricane Katrina). We nickname such potential future TCs, characterized by rarity, extreme impact, and retrospective predictability, "black swans" (Nassim Nicholas Taleb, 2007). As, by definition, black swan TCs have yet to happen, statistical methods that solely rely on historical track data cannot predict their occurrence. Global climate models lack the capability to predict intense storms, even with a resolution as high as 14 km (Emanuel et al. 2010). Also, most dynamic downscaling methods (e.g., Bender et al. 2010) are still limited in horizontal resolution and are too expensive to implement to generate enough events to include rare ones. In this study, we apply a simpler statistical/deterministic hurricane model (Emanuel et al. 2006) to simulate large numbers of synthetic storms under a given (observed or projected) climate condition. The method has been shown to generate realistic extremes in various basins (Emanuel et al. 2008 and 2010). We also apply a hydrodynamic model (ADCIRC; Luettich et al. 1992) to simulate the storm surges generated by these storms. We then search for black swan TCs, in terms of the joint wind and surge damage potential, in the generated large databases. Heavy rainfall is another important TC hazard and will be considered in a future study. We focus on three areas: Tampa Bay in the U.S., the Persian Gulf, and Darwin in Australia. Tampa Bay is highly vulnerable to storm surge as it is surrounded by shallow water and low-lying lands, much of which may be inundated by a storm tide of 6 m. High surges are generated by storms with a broad

Runoff-generated debris flows: observations and modeling of surge initiation, magnitude, and frequency

Science.gov (United States)

Kean, Jason W.; McCoy, Scott W.; Tucker, Gregory E.; Staley, Dennis M.; Coe, Jeffrey A.

2013-01-01

Runoff during intense rainstorms plays a major role in generating debris flows in many alpine areas and burned steeplands. Yet compared to debris flow initiation from shallow landslides, the mechanics by which runoff generates a debris flow are less understood. To better understand debris flow initiation by surface water runoff, we monitored flow stage and rainfall associated with debris flows in the headwaters of two small catchments: a bedrock-dominated alpine basin in central Colorado (0.06 km2) and a recently burned area in southern California (0.01 km2). We also obtained video footage of debris flow initiation and flow dynamics from three cameras at the Colorado site. Stage observations at both sites display distinct patterns in debris flow surge characteristics relative to rainfall intensity (I). We observe small, quasiperiodic surges at low I; large, quasiperiodic surges at intermediate I; and a single large surge followed by small-amplitude fluctuations about a more steady high flow at high I. Video observations of surge formation lead us to the hypothesis that these flow patterns are controlled by upstream variations in channel slope, in which low-gradient sections act as “sediment capacitors,” temporarily storing incoming bed load transported by water flow and periodically releasing the accumulated sediment as a debris flow surge. To explore this hypothesis, we develop a simple one-dimensional morphodynamic model of a sediment capacitor that consists of a system of coupled equations for water flow, bed load transport, slope stability, and mass flow. This model reproduces the essential patterns in surge magnitude and frequency with rainfall intensity observed at the two field sites and provides a new framework for predicting the runoff threshold for debris flow initiation in a burned or alpine setting.

Study of the responsible factors for the closure of an intermittent washout during a storm surge, Rio Grande do Sul, Brazil

OpenAIRE

Serpa, Christian Garcia; Romeu, Marco Antônio Rígola; Fontoura, Jose Antonio Scotti; Calliari, Lauro Julio; Melo Filho, Eloi; Albuquerque, Miguel da Guia

2011-01-01

The washouts are water courses essential to the drainage of the water accumulated in the backshore zone, and are responsible for great ruptures in the dunes field. They supply the swash zone with large amounts of sediment. The study area is located a few kilometers south of the Patos Lagoon Inlet. This study measures the contribution of the wind, the waves, the atmospheric pressure and the tide on the elevation of the sea level in a period when the beach has suffered the impact of a storm sur...

The dynamics of surge in compression systems

Indian Academy of Sciences (India)

is of interest to study compression-system surge to understand its dynamics in order ... Internal problems like compressor going into rotating stall, resulting in loss of ... of water column, was used for mass-flow measurement at the impeller entry.

Relationship between substorms and storms

International Nuclear Information System (INIS)

Kamide, Y.

1980-01-01

In an attempt to deduce a plausible working model of the relationship between magnetospheric substorms and storms, recent relevant studies of various processes occurring during disturbed periods are integrated along with some theoretical suggestions. It has been shown that the main phase of geomagnetic storms is associated with the successive occurrence of intense substorms and with the sustained southward component of the interplanetary magnetic field (IMF). However, these relations are only qualitatively understood, and thus basic questions remain unanswered involving the hypothesis whether a magnetic storm is a non-linear (or linear) superposition of intense substorms, each of which constitutes an elementary storm, or the main phase of magnetic storms occurs as a result of the intense southward IMF which enhances magnetospheric convection and increases occurrence probability of substorms. (Auth.)

Role of cold surge and MJO on rainfall enhancement over indonesia during east asian winter monsoon

Science.gov (United States)

Fauzi, R. R.; Hidayat, R.

2018-05-01

Intensity of precipitation in Indonesia is influenced by convection and propagation of southwest wind. Objective of this study is to analyze the relationship between cold surge and the phenomenon of intra-seasonal climate variability Madden-julian Oscillation (MJO) for affecting precipitation in Indonesia. The data used for identifying the occurrence of cold surge are meridional wind speed data from the ERA-Interim. In addition, this study also used RMM1 and RMM2 index data from Bureau of Meteorology (BOM) for identifying MJO events. The results showed that during East Asian Winter Monsoon (EAWM) in 15 years (2000-2015), there are 362 cold surge events, 186 MJO events, and 113 cold surge events were associated with MJO events. The spread of cold surge can penetrate to equator and brought mass of water vapor that causes dominant precipitation in the Indonesian Sea up to 50-75% from climatological precipitation during EAWM. The MJO convection activity that moves from west to east also increases precipitation, but the distribution of rainfall is wider than cold surge, especially in Eastern Indonesia. MJO and cold surge simultaneously can increase rainfall over 100-150% in any Indonesian region that affected by MJO and cold surge events. The mechanism of heavy rainfall is illustrated by high activity of moisture transport in areas such as Java Sea and coastal areas of Indonesia.

NCDC Storm Events Database

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Storm Data is provided by the National Weather Service (NWS) and contain statistics on personal injuries and damage estimates. Storm Data covers the United States of...

Predicting the occurrence of super-storms

Directory of Open Access Journals (Sweden)

N. Srivastava

2005-11-01

Full Text Available A comparative study of five super-storms (Dst<-300 nT of the current solar cycle after the launch of SoHO, to identify solar and interplanetary variables that influence the magnitude of resulting geomagnetic storms, is described. Amongst solar variables, the initial speed of a CME is considered the most reliable predictor of the strength of the associated geomagnetic storm because fast mass ejections are responsible for building up the ram pressure at the Earth's magnetosphere. However, although most of the super-storms studied were associated with high speed CMEs, the Dst index of the resulting geomagnetic storms varied between -300 to -472 nT. The most intense storm of 20 November 2003, (Dst ~ -472 nT had its source in a comparatively smaller active region and was associated with a relatively weaker, M-class flare while all other super-storms had their origins in large active regions and were associated with strong X-class flares. However, this superstorm did not show any associated extraordinary solar and interplanetary characteristics. The study also reveals the challenge in the reliable prediction of the magnitude of a geomagnetic storm from solar and interplanetary variables.

The structure of the big magnetic storms

International Nuclear Information System (INIS)

Mihajlivich, J. Spomenko; Chop, Rudi; Palangio, Paolo

2010-01-01

The records of geomagnetic activity during Solar Cycles 22 and 23 (which occurred from 1986 to 2006) indicate several extremely intensive A-class geomagnetic storms. These were storms classified in the category of the Big Magnetic Storms. In a year of maximum solar activity during Solar Cycle 23, or more precisely, during a phase designated as a post-maximum phase in solar activity (PPM - Phase Post maximum), near the autumn equinox, on 29, October 2003, an extremely strong and intensive magnetic storm was recorded. In the first half of November 2004 (7, November 2004) an intensive magnetic storm was recorded (the Class Big Magnetic Storm). The level of geomagnetic field variations which were recorded for the selected Big Magnetic Storms, was ΔD st=350 nT. For the Big Magnetic Storms the indicated three-hour interval indices geomagnetic activity was Kp = 9. This study presents the spectral composition of the Di - variations which were recorded during magnetic storms in October 2003 and November 2004. (Author)

The Impact of Climate Change on New York City's Coastal Flood Hazard: Increasing Flood Heights from the Pre-Industrial to 2300 CE

Science.gov (United States)

Garner, A. J.; Mann, M. E.; Emanuel, K.; Kopp, R. E.; Lin, N.; Alley, R. B.; Horton, B.; Deconto, R. M.; Donnelly, J. P.; Pollard, D.

2017-12-01

The flood hazard in New York City depends on both storm surges and rising sea levels. We combine modeled storm surges with probabilistic sea-level rise projections to assess future coastal inundation in New York City from the pre-industrial through 2300 CE. The storm surges are derived from large sets of synthetic tropical cyclones, downscaled from RCP 8.5 runs of three CMIP5 models. The sea-level rise projections include the collapse of the Antarctic ice sheet to assess future coastal inundation. CMIP5 models indicate that there will be minimal change in storm-surge heights from 2010 to 2100 or 2300, because the predicted strengthening of the strongest storms will be compensated by storm tracks moving offshore at the latitude of New York City. However, projected sea-level rise causes overall flood heights associated with tropical cyclones in New York City in coming centuries to increase greatly compared to pre-industrial or modern flood heights. We find that the 1-in-500-year flood event increases from 3.4 m above mean tidal level during 1970-2005 to 3.9 - 4.8 m above mean tidal level by 2080-2100, and ranges from 2.8 - 13.0 m above mean tidal level by 2280-2300. Further, we find that the return period of a 2.25 m flood has decreased from 500 years prior to 1800 to 25 years during 1970-2005, and further decreases to 5 years by 2030 - 2045 in 95% of our simulations.

Evaluation of the STORM model storm-time corrections for middle latitude

Czech Academy of Sciences Publication Activity Database

Burešová, Dalia; McKinnell, L.- A.; Šindelářová, Tereza; de la Morena, B. A.

2010-01-01

Roč. 46, č. 8 (2010), s. 1039-1046 ISSN 0273-1177 R&D Projects: GA ČR GA205/08/1356; GA AV ČR 1QS300120506 Institutional research plan: CEZ:AV0Z30420517 Keywords : Ionosphere * Geomagnetic storms * STORM model * International Reference Ionosphere (IRI) Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 1.076, year: 2010

Alternate Care Sites for the Management of Medical Surge in Disasters

Science.gov (United States)

2013-12-01

care facilities are in place  Plan for community based surge hospital bed surge capacity is in place  A 50-bed nursing subunit—per 50,000...attempt to assess the preparedness of the hospital system, HHS/ASPR commissioned The Center for Biosecurity of UPMC to examine various responses to...catastrophic health efforts. The 11 report The Next Challenge in Healthcare Preparedness: Catastrophic Health Events (Center for Biosecurity of UPMC

Control of Surge in Centrifugal Compressors by Active Magnetic Bearings Theory and Implementation

CERN Document Server

Yoon, Se Young; Allaire, Paul E

2013-01-01

Control of Surge in Centrifugal Compressors by Active Magnetic Bearings sets out the fundamentals of integrating the active magnetic bearing (AMB) rotor suspension technology in compressor systems, and describes how this relatively new bearing technology can be employed in the active control of compressor surge. The authors provide a self-contained and comprehensive review of rotordynamics and the fundamentals of the AMB technology. The active stabilization of compressor surge employing AMBs in a machine is fully explored, from the modeling of the instability and the design of feedback controllers, to the implementation and experimental testing of the control algorithms in a specially-constructed, industrial-size centrifugal compression system. The results of these tests demonstrate the great potential of the new surge control method developed in this text. This book will be useful for engineers in industries that involve turbocompressors and magnetic bearings, as well as for researchers and graduate students...

Countercurrent Air-Water Flow in a Scale-Down Model of a Pressurizer Surge Line

Directory of Open Access Journals (Sweden)

Takashi Futatsugi

2012-01-01

Full Text Available Steam generated in a reactor core and water condensed in a pressurizer form a countercurrent flow in a surge line between a hot leg and the pressurizer during reflux cooling. Characteristics of countercurrent flow limitation (CCFL in a 1/10-scale model of the surge line were measured using air and water at atmospheric pressure and room temperature. The experimental results show that CCFL takes place at three different locations, that is, at the upper junction, in the surge line, and at the lower junction, and its characteristics are governed by the most dominating flow limitation among the three. Effects of inclination angle and elbows of the surge line on CCFL characteristics were also investigated experimentally. The effects of inclination angle on CCFL depend on the flow direction, that is, the effect is large for the nearly horizontal flow and small for the vertical flow at the upper junction. The presence of elbows increases the flow limitation in the surge line, whereas the flow limitations at the upper and lower junctions do not depend on the presence of elbows.

Experimental Study on Active Control of Surge in a Centrifugal Compression System

Directory of Open Access Journals (Sweden)

Nie Chaoqun

2000-01-01

Full Text Available An experimental study has been carried out on the active control of surge in a centrifugal compression system. With a computerized on-line control scheme, the surge phenomenon is suppressed and the stable operating range of the system is extended. In order to design the active control scheme and choose the desired parameters of the control system inputs, special emphases have been placed on the development of surge inception and the nonlinear interaction between the system and the actuator. By use of the method designed in the present work, the results of active control onsurge have been demonstrated for the different B parameters, different prescribed criteria and different control frequencies.

Geomagnetic storms

International Nuclear Information System (INIS)

McNamara, A.G.

1980-01-01

Disturbances due to geomagnetic storms can affect the functioning of communications satellites and of power lines and other long conductors. Two general classes of geomagnetic activity can be distinguished: ionospheric current flow (the auroral electrojet), and magnetospheric compression. Super magnetic storms, such as the one of August 1972, can occur at any time and average about 17 occurrences per century. Electrical transmission systems can be made more tolerant of such events at a price, but the most effective way to minimize damage is by better operator training coupled with effective early warning systems. (LL)

Cortisol Interferes with the Estradiol-Induced Surge of Luteinizing Hormone in the Ewe1

Science.gov (United States)

Wagenmaker, Elizabeth R.; Breen, Kellie M.; Oakley, Amy E.; Pierce, Bree N.; Tilbrook, Alan J.; Turner, Anne I.; Karsch, Fred J.

2008-01-01

Two experiments were conducted to test the hypothesis that cortisol interferes with the positive feedback action of estradiol that induces the luteinizing hormone (LH) surge. Ovariectomized sheep were treated sequentially with progesterone and estradiol to create artificial estrous cycles. Cortisol or vehicle (saline) was infused from 2 h before the estradiol stimulus through the time of the anticipated LH surge in the artificial follicular phase of two successive cycles. The plasma cortisol increment produced by infusion was ∼1.5 times greater than maximal concentrations seen during infusion of endotoxin, which is a model of immune/inflammatory stress. In experiment 1, half of the ewes received vehicle in the first cycle and cortisol in the second; the others were treated in reverse order. All ewes responded with an LH surge. Cortisol delayed the LH surge and reduced its amplitude, but both effects were observed only in the second cycle. Experiment 2 was modified to provide better control for a cycle effect. Four treatment sequences were tested (cycle 1-cycle 2): vehicle-vehicle, cortisol-cortisol, vehicle-cortisol, cortisol-vehicle. Again, cortisol delayed but did not block the LH surge, and this delay occurred in both cycles. Thus, an elevation in plasma cortisol can interfere with the positive feedback action of estradiol by delaying and attenuating the LH surge. PMID:19056703

Predicting the occurrence of super-storms

Directory of Open Access Journals (Sweden)

N. Srivastava

2005-11-01

Full Text Available A comparative study of five super-storms (D_st<-300 nT of the current solar cycle after the launch of SoHO, to identify solar and interplanetary variables that influence the magnitude of resulting geomagnetic storms, is described. Amongst solar variables, the initial speed of a CME is considered the most reliable predictor of the strength of the associated geomagnetic storm because fast mass ejections are responsible for building up the ram pressure at the Earth's magnetosphere. However, although most of the super-storms studied were associated with high speed CMEs, the D_st index of the resulting geomagnetic storms varied between -300 to -472 nT. The most intense storm of 20 November 2003, (D_st ~ -472 nT had its source in a comparatively smaller active region and was associated with a relatively weaker, M-class flare while all other super-storms had their origins in large active regions and were associated with strong X-class flares. However, this superstorm did not show any associated extraordinary solar and interplanetary characteristics. The study also reveals the challenge in the reliable prediction of the magnitude of a geomagnetic storm from solar and interplanetary variables.

Thyroid storm: an updated review.

Science.gov (United States)

Chiha, Maguy; Samarasinghe, Shanika; Kabaker, Adam S

2015-03-01

Thyroid storm, an endocrine emergency first described in 1926, remains a diagnostic and therapeutic challenge. No laboratory abnormalities are specific to thyroid storm, and the available scoring system is based on the clinical criteria. The exact mechanisms underlying the development of thyroid storm from uncomplicated hyperthyroidism are not well understood. A heightened response to thyroid hormone is often incriminated along with increased or abrupt availability of free hormones. Patients exhibit exaggerated signs and symptoms of hyperthyroidism and varying degrees of organ decompensation. Treatment should be initiated promptly targeting all steps of thyroid hormone formation, release, and action. Patients who fail medical therapy should be treated with therapeutic plasma exchange or thyroidectomy. The mortality of thyroid storm is currently reported at 10%. Patients who have survived thyroid storm should receive definite therapy for their underlying hyperthyroidism to avoid any recurrence of this potentially fatal condition. © The Author(s) 2013.

The electric storm of November 1882

Science.gov (United States)

Love, Jeffrey J.

2018-01-01

In November 1882, an intense magnetic storm related to a large sunspot group caused widespread interference to telegraph and telephone systems and provided spectacular and unusual auroral displays. The (ring current) storm time disturbance index for this storm reached maximum −Dst ≈ 386 nT, comparable to Halloween storm of 29–31 October 2003, but from 17 to 20 November the aa midlatitude geomagnetic disturbance index averaged 214.25 nT, the highest 4 day level of disturbance since the beginning of aa index in 1868. This storm contributed to scientists' understanding of the reality of solar‐terrestrial interaction. Past occurrences of magnetic storms, like that of November 1882, can inform modern evaluations of the deleterious effects that a magnetic superstorm might have on technological systems of importance to society.

Brief communication: The Khurdopin glacier surge revisited - extreme flow velocities and formation of a dammed lake in 2017

Science.gov (United States)

Steiner, Jakob F.; Kraaijenbrink, Philip D. A.; Jiduc, Sergiu G.; Immerzeel, Walter W.

2018-01-01

Glacier surges occur regularly in the Karakoram, but the driving mechanisms, their frequency and its relation to a changing climate remain unclear. In this study, we use digital elevation models and Landsat imagery in combination with high-resolution imagery from the Planet satellite constellation to quantify surface elevation changes and flow velocities during a glacier surge of the Khurdopin Glacier in 2017. Results reveal that an accumulation of ice volume above a clearly defined steep section of the glacier tongue since the last surge in 1999 eventually led to a rapid surge in May 2017 peaking with velocities above 5000 m a-1, which were among the fastest rates globally for a mountain glacier. Our data reveal that velocities on the lower tongue increase steadily during a 4-year build-up phase prior to the actual surge only to then rapidly peak and decrease again within a few months, which confirms earlier observations with a higher frequency of available velocity data. The surge return period between the reported surges remains relatively constant at ca. 20 years. We show the potential of a combination of repeat Planet and ASTER imagery to (a) capture peak surge velocities that are easily missed by less frequent Landsat imagery, (b) observe surface changes that indicate potential drivers of a surge and (c) monitor hazards associated with a surge. At Khurdopin specifically, we observe that the surging glacier blocks the river in the valley and causes a lake to form, which may grow in subsequent years and could pose threats to downstream settlements and infrastructure in the case of a sudden breach.

Estimating the Risk of Tropical Cyclone Characteristics Along the United States Gulf of Mexico Coastline Using Different Statistical Approaches

Science.gov (United States)

Trepanier, J. C.; Ellis, K.; Jagger, T.; Needham, H.; Yuan, J.

2017-12-01

Tropical cyclones, with their high wind speeds, high rainfall totals and deep storm surges, frequently strike the United States Gulf of Mexico coastline influencing millions of people and disrupting off shore economic activities. Events, such as Hurricane Katrina in 2005 and Hurricane Isaac in 2012, can be physically different but still provide detrimental effects due to their locations of influence. There are a wide variety of ways to estimate the risk of occurrence of extreme tropical cyclones. Here, the combined risk of tropical cyclone storm surge and nearshore wind speed using a statistical copula is provided for 22 Gulf of Mexico coastal cities. Of the cities considered, Bay St. Louis, Mississippi has the shortest return period for a tropical cyclone with at least a 50 m s-1 nearshore wind speed and a three meter surge (19.5 years, 17.1-23.5). Additionally, a multivariate regression model is provided estimating the compound effects of tropical cyclone tracks, landfall central pressure, the amount of accumulated precipitation, and storm surge for five locations around Lake Pontchartrain in Louisiana. It is shown the most intense tropical cyclones typically approach from the south and a small change in the amount of rainfall or landfall central pressure leads to a large change in the final storm surge depth. Data are used from the National Hurricane Center, U-Surge, SURGEDAT, and Cooperative Observer Program. The differences in the two statistical approaches are discussed, along with the advantages and limitations to each. The goal of combining the results of the two studies is to gain a better understanding of the most appropriate risk estimation technique for a given area.

Investigation of surge protective devices operation of a wind generator

International Nuclear Information System (INIS)

Dimitrov, D.; Vasileva, M.

2008-01-01

The interest to the investments in a wind energetics increases in the last years. The wind energetics is the fastest developing direction in the energetics in global scale. The wind energy is more attractive because its prices are lower in comparison of the other technologies for generating energy. The right choice of the surge protective devices has the important meaning on building and exploitation of the wind generators. The aim of this paper is investigation of the surge protective devices operation when they are installation to a wind generator. (authors)

Three-Dimensional Numerical Analysis of Compound Lining in Complex Underground Surge-Shaft Structure

Directory of Open Access Journals (Sweden)

Juntao Chen

2015-01-01

Full Text Available The mechanical behavior of lining structure of deep-embedded cylinder surge shaft with multifork tunnel is analyzed using three-dimensional nonlinear FEM. With the elastic-plastic constitutive relations of rock mass imported and the implicit bolt element and distributed concrete cracking model adopted, a computing method of complex surge shaft is presented for the simulation of underground excavations and concrete lining cracks. In order to reflect the interaction and initial gap between rock mass and concrete lining, a three-dimensional nonlinear interface element is adopted, which can take into account both the normal and tangential characteristics. By an actual engineering computation, the distortion characteristics and stress distribution rules of the dimensional multifork surge-shaft lining structure under different behavior are revealed. The results verify the rationality and feasibility of this computation model and method and provide a new idea and reference for the complex surge-shaft design and construction.

Ionospheric storms at geophysically-equivalent sites – Part 1: Storm-time patterns for sub-auroral ionospheres

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M. Mendillo

2009-04-01

Full Text Available The systematic study of ionospheric storms has been conducted primarily with groundbased data from the Northern Hemisphere. Significant progress has been made in defining typical morphology patterns at all latitudes; mechanisms have been identified and tested via modeling. At higher mid-latitudes (sites that are typically sub-auroral during non-storm conditions, the processes that change significantly during storms can be of comparable magnitudes, but with different time constants. These include ionospheric plasma dynamics from the penetration of magnetospheric electric fields, enhancements to thermospheric winds due to auroral and Joule heating inputs, disturbance dynamo electrodynamics driven by such winds, and thermospheric composition changes due to the changed circulation patterns. The ~12° tilt of the geomagnetic field axis causes significant longitude effects in all of these processes in the Northern Hemisphere. A complementary series of longitude effects would be expected to occur in the Southern Hemisphere. In this paper we begin a series of studies to investigate the longitudinal-hemispheric similarities and differences in the response of the ionosphere's peak electron density to geomagnetic storms. The ionosonde stations at Wallops Island (VA and Hobart (Tasmania have comparable geographic and geomagnetic latitudes for sub-auroral locations, are situated at longitudes close to that of the dipole tilt, and thus serve as our candidate station-pair choice for studies of ionospheric storms at geophysically-comparable locations. They have an excellent record of observations of the ionospheric penetration frequency (foF2 spanning several solar cycles, and thus are suitable for long-term studies. During solar cycle #20 (1964–1976, 206 geomagnetic storms occurred that had Ap≥30 or Kp≥5 for at least one day of the storm. Our analysis of average storm-time perturbations (percent deviations from the monthly means showed a remarkable

Effect of layout on surge line thermal stratification

International Nuclear Information System (INIS)

Lai Jianyong; Huang Wei

2011-01-01

In order to analyze and evaluate the effect of layout on the thermal stratification for PWR Pressurizer surge line, numerical simulation by Computational Fluid Dynamics (CFD) method is taken on 6 kinds of layout improvement with 2 improvement schemes, i.e., increasing the obliquity of quasi horizontal section and adding a vertical pipe between the quasi horizontal section and next elbow, and the maximum temperature differences of quasi horizontal section of surge line of various layouts under different flowrate are obtained. The comparison shows that, the increasing of the obliquity of quasi horizontal section can mitigate the thermal stratification phenomena but can not eliminate this phenomena, while the adding of a vertical pipe between the quasi horizontal section and next elbow can effectively mitigate and eliminate the thermal stratification phenomena. (authors)

The Effect of Sub-Auroral Polarization Streams (SAPS) on Ionosphere and Thermosphere during 2015 St. Patrick's Day storm: Global Ionosphere-Thermosphere Model (GITM) Simulations

Science.gov (United States)

Guo, J.; Deng, Y.; Zhang, D.; Lu, Y.; Sheng, C.

2017-12-01

Sub-Auroral Polarization Streams (SAPS) are incorporated into the non-hydrostatic Global Ionosphere-Thermosphere Model (GITM), revealing the complex effects on neutral dynamics and ion-neutral coupling processes. The intense westward ion stream could enhance the neutral zonal wind within the SAPS channel. Through neutral dynamics the neutrals then divide into two streams, one turns poleward and the other turns equatorward, forming a two-cell pattern in the SAPS-changed wind. The significant Joule heating induced by SAPS also leads to traveling atmospheric disturbances (TAD) accompanied by traveling ionospheric disturbances (TID), increasing the total electron content (TEC) by 2-8 TECu in the mid-latitude ionosphere. We investigate the potential causes of the reported poleward wind surge during the St. Patrick's Day storm in 2015. It is confirmed that Coriolis force on the westward zonal wind can contribute the poleward wind during post-SAPS interval. In addition, the simulations imply that the sudden decrease of heating rate within auroral oval could result in a TAD propagating equatorward, which could also be responsible for the sudden poleward wind surge. This study highlights the complicated effects of SAPS on ion-neutral coupling and neutral dynamics.

A Perspective on Sea Level Rise and Coastal Storm Surge from Southern and Eastern Africa: A Case Study Near Durban, South Africa

Directory of Open Access Journals (Sweden)

Derek D. Stretch

2012-03-01

Full Text Available Recent coastal storms in southern Africa have highlighted the need for more proactive management of the coastline. Within the southern and eastern African region the availability of coastal information is poor. The greatest gap in information is the likely effects of a combination of severe sea storms and future sea level rise (SLR on the shoreline. This lack of information creates a barrier to informed decision making. This research outlines a practical localized approach to this problem, which can be applied as a first order assessment within the region. In so doing it provides a cost effective and simple decision support tool for the built environment and disaster professionals in development and disaster assessments. In a South African context the newly promulgated Integrated Coastal Management Act requires that all proposed coastal developments take into consideration future SLR, however such information currently does not exist, despite it being vital for informed planning in the coastal zone. This practical approach has been applied to the coastline of Durban, South Africa as a case study. The outputs are presented in a Geographic Information System (GIS based freeware viewer tool enabling ease of access to both professionals and laypersons. This demonstrates that a simple approach can provide valuable information about the current and future risk of flooding and coastal erosion under climate change to buildings, infrastructure as well as natural features along the coast.

Impact of Hurricane Irma in the post-recovery of Matthew in South Carolina, the South Atlantic Bight (Western Atlantic)

Science.gov (United States)

Harris, M. S.; Levine, N. S.; Jaume, S. C.; Hendricks, J. K.; Rubin, N. D.; Hernandez, J. L.

2017-12-01

The impacts on the Southeastern United States (SEUS, Western Atlantic) from Hurricane Irma in Sept 2017 were felt primarily on the active coastline with the third highest inland storm surge in Charleston and Savannah since the 19th Century. Coastal geometry, waves, and wind duration had a strong influence on the storm surge and coastal erosion impacts regionally. To the North and immediate South, impacts were much less. A full year after the 2016 hurricane season (Hurricane Matthew), the lack of regional recovery reduced protection against Irma. The most devastating impacts of Irma in the SAB occurred from 300 to 500 km away from the eye, on the opposite side of the Floridian peninsula. As Irma devastated the Caribbean, winds started to increases off the SAB on September 8 in the early morning, continuing for the next 3 days and blowing directly towards the SC and GA coasts. Tide gauges started to respond the night of September 8, while waves started arriving in the SEUS around Sept 6. Coastal erosion pre- and post-Irma has been calculated for Central SC using vertical and oblique aerial photos. Citizen Science initiatives through the Charleston Resilience Network have provided on-the-ground data during storms when transportation infrastructures were closed, and allow for ground-truth post-storm of surge and impacts. Said information was collected through Facebook, Google, and other social media. Pictures with timestamps and water heights were collected and are validating inundation flood maps generated for the Charleston SC region. The maps have 1-m horizontal and 7- to 15-cm vertical accuracy. Inundation surfaces were generated at MHHW up to a maximum surge in 6 inch increments. The flood extents of the modeled surge and the photographic evidence show a high correspondence. Storm surge measurements from RTK-GPS provide regional coverage of surge elevations from the coast, inland, and allow for testing of modeled results and model tuning. With Hurricane Irma

Multi-proxy Characterization of Two Recent Storm Deposits Attributed to Hurricanes Rita and Ike in the Chenier Plain of Southwestern Louisiana

Science.gov (United States)

Yao, Q.; Liu, K. B.; Ryu, J.

2017-12-01

The Chenier Plain in southwestern Louisiana owes its origin to dynamic depositional processes that are dominated by delta-switching of the Mississippi River to the east, while frequent hurricane activities also play an important role in its geomorphology and sedimentary history. However, despite several studies in the literature, the sediment-stratigraphic characteristics of recent or historic hurricane deposits are still not well documented from the Chenier Plain. In 2005 and 2008, Hurricane Rita (category 3) and Ike (category 2) made landfall on the coasts of Louisiana and Texas. Remote sensing images confirm that the Rockefeller Wildlife Refuge, located at the east end of the Louisiana Chenier Plain, was heavily impacted by both hurricanes. We analyzed the lithology and chemical stratigraphy of three 30 cm sediment monoliths (ROC-1, ROC-2, and ROC-3) recovered from a coastal saltmarsh in the Rockefeller Wildlife Refuge to identify the event deposits attributed to these two storms. Each monolith contains 2 distinct light-colored clastic sediment layers imbedded in brown organic clay. The loss-on-ignition and X-ray fluorescence results show that the hurricane layers have increased contents of Ca, Sr, Zr, and carbonates and decreased contents of water and organics. Surprisingly, despite its greater intensity and more severe impacts, Hurricane Rita left a much thinner storm deposit than did Hurricane Ike in all monoliths. Satellite data reveal that Hurricane Rita caused significant coastal erosion and shoreline recession, rendering the sampling sites much closer to the beach and ocean and therefore more prone to storm surges and overwash deposition than when Hurricane Ike struck three years later. Our results suggest that site-to-sea distance, which affects a study site's paleotempestological sensitivity, can play a bigger role in affecting the thicknesses of storm deposits than the intensity of the hurricane.

Great magnetic storms

International Nuclear Information System (INIS)

Tsurutani, B.T.; Yen Te Lee; Tang, F.; Gonzalez, W.D.

1992-01-01

The five largest magnetic storms that occurred between 1971 and 1986 are studied to determine their solar and interplanetary causes. All of the events are found to be associated with high speed solar wind streams led by collisionless shocks. The high speed streams are clearly related to identifiable solar flares. It is found that (1) it is the extreme values of the southward interplanetary magnetic fields rather than solar wind speeds that are the primary causes of great magnetic storms, (2) shocked and draped sheath fields preceding the driver gas (magnetic cloud) are at least as effective in causing the onset of great magnetic storms (3 of 5 events ) as the strong fields within the driver gas itself, and (3) precursor southward fields ahead of the high speed streams allow the shock compression mechanism (item 2) to be particularly geoeffective

Assessing storm erosion hazards

NARCIS (Netherlands)

Ranasinghe, Ranasinghe W M R J B; Callaghan, D.; Ciavola, Paolo; Coco, Giovanni

2017-01-01

The storm erosion hazard on coasts is usually expressed as an erosion volume and/or associated episodic coastline retreat. The accurate assessment of present-day and future storm erosion volumes is a key task for coastal zone managers, planners and engineers. There are four main approaches that can

Flow in sodium loop surge tank

International Nuclear Information System (INIS)

Matal, O.; Martoch, J.

1977-01-01

The alternate liquid flow, the condition of vortex formation, gas entrainment in the discharge and the liquid level characteristics are studied using the models of the vertical and horizontal surge tanks of a sodium circuit with pump and heat exchangers. The conditions for vortex formation are more favourable in the vertical cylindrical tank than in the horizontal tank. The size of the vortex produced in the tank is affected by the initial speed circulation, due as a rule to an unsuitable inlet design. The proposed design considers an inlet below the sodium level using capped perforated pipes. Vortex formation, gas transport to the discharge pipe and turbulences of the liquid in the tank may be prevented by dividing the tank to the discharge and the inlet areas using perforated partitions, and by inserting the discharge cylinder above the discharge pipe outflow. The liquid level in the tank may be calmed by screens or by perforated plates. The adaptation of the surge tank of the sodium circuit will probably eliminate vortex formation and the entrainment of cover gas into the discharge piping and the sodium circuit under nominal conditions. (J.B.)

46 CFR 169.329 - Storm rails.

Science.gov (United States)

2010-10-01

... 46 Shipping 7 2010-10-01 2010-10-01 false Storm rails. 169.329 Section 169.329 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Construction and Arrangement Rails and Guards § 169.329 Storm rails. Suitable storm rails or hand grabs must be...

46 CFR 72.40-10 - Storm rails.

Science.gov (United States)

2010-10-01

... 46 Shipping 3 2010-10-01 2010-10-01 false Storm rails. 72.40-10 Section 72.40-10 Shipping COAST... and Guards § 72.40-10 Storm rails. (a) Suitable storm rails shall be installed in all passageways and at the deckhouse sides where passengers or crew might have normal access. Storm rails shall be...

A Flood Risk Assessment of the LaHave River Watershed, Canada Using GIS Techniques and an Unstructured Grid Combined River-Coastal Hydrodynamic Model