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Sample records for plast reconstr surg

  1. Question mark ears, temporo-mandibular joint malformation and hypotonia: auriculo-condylar syndrome or a distinct entity?

    PubMed

    Priolo, M; Lerone, M; Rosaia, L; Calcagno, E P; Sadeghi, A K; Ghezzi, F; Ravazzolo, R; Silengo, M

    2000-10-01

    We report a boy with prominent, peculiarly malformed ears, abnormality of the ramus of the mandible and hypotonia. An isolated peculiar bilateral ear deformity named 'question mark ear' has been delineated in plastic reconstruction surgery reviews [Cosman et al., 1970 Plast Reconstr Surg 46:454-457; Cosman (1984) Plast Reconstr Surg 73:572-576; Takato et al. (1989) Ann Plast Surg 22:69-73; Brodovsky (1997) Plast Reconstr Surg 100:1254-1257; Park (1998) Plast Reconstr Surg 101:1620-1623; Al-Quattan (1998) Plast Reconstr Surg 102:439-441] and a similar deformity of the ear and changes in the temporo-mandibular joint and condyle has been described by Jampol et al. [(1998) Am J Med Genet 75:449-452] and by Guion-Almeida et al. [(1999) Am J Med Genet 86:130-133]. The present case may be the third description of this malformation complex with additional clinical features characterized by hypotonia and mild developmental delay, or possibly a new distinct entity.

  2. Accelerated Functional Recovery after Skeletal Muscle Ischemia-reperfusion Injury using Freshly Isolated Bone Marrow Cells

    DTIC Science & Technology

    2014-01-03

    nerve function in diabetic neuropathy . PLoS One 2011;6(11):e27458. [22] Corona BT, Wenke JC, Walters TJ, et al. Intramuscular transplantation and...211. [29] Lin CD, Allori AC, Macklin JE, et al. Topical lineage negative progenitor cell therapy for diabetic wounds. Plast Reconstr Surg 2008;122(5

  3. Surging Onward

    NASA Image and Video Library

    2006-09-14

    A brilliant spot of sunlight, the opposition effect, travels outward across the rings as the Cassini spacecraft orbits Saturn. This surge in ring brightness is created around the point directly opposite the Sun from the spacecraft

  4. Covalent immobilization of invertase on polyurethane, plast-film and ferromagnetic Dacron.

    PubMed

    Cadena, P G; Jeronimo, R A S; Melo, J M; Silva, R A; Lima Filho, J L; Pimentel, M C B

    2010-03-01

    Invertase was covalently immobilized on polyurethane (PU), inox plate covered with plast-film layer and ferromagnetic azide-Dacron. The immobilization processes, physico-chemical parameters and a model for coupling reactions were studied. The preliminary studies for selection of the support showed that the best activity was obtained for PU treated with HCl, polyethylenimine and glutaraldehyde (156.7+/-4.9 U/g support). All plast-film-invertase derivatives did not show activity and the Dacron-invertase derivative showed an activity of 105.39 U/g support. The invertase immobilized in presence of substrate (10% w/v sucrose) was the most efficient (832.74+/-1.48 U/g support). The optimal pH was shifted from 4.5 (free enzyme) to 5.0 (immobilized derivative) and optimal temperature was not affected. Activation energy values of free enzyme, Dacron-invertase and PU-invertase were 32.4+/-0.34 kJ/mol, 33.4+/-0.36 kJ/mol and 44.0+/-0.67 kJ/mol, respectively. The PU-invertase could be used over 2 months without considerable activity loss (68.5% activity retention) and retained 12.6% (287.97+/-27.9U/g support) of the activity after five cycles.

  5. Historical Article: Hirudo medicinalis: ancient origins of, and trends in the use of medicinal leeches throughout history.

    PubMed

    Whitaker, I S; Rao, J; Izadi, D; Butler, P E

    2004-04-01

    Blood letting and the therapeutic use of Hirudo medicinalis date back to ancient Egypt and the beginning of civilisation. Their popularity has varied over the years, reaching such a peak in Europe between 1825 and 1850 that supplies were exhausted. Towards the end of the century they fell out of favour and, during this period, the leech, once used by the physicians of emperors and influential academic surgeons, became associated with lay therapists and quackery. Leeches have enjoyed a renaissance in reconstructive microsurgery during the last 15 years, having been used by maxillofacial [Br. J. Oral Maxillofac. Surg 41 (2003) 44] and other reconstructive surgeons to aid salvage of compromised microvascular free tissue transfers [Laryngoscope 108 (1998) 1129; Br. J. Plast. Surg. 34 (1984) 358], replanted digits [Int. J. Microsurg. 3 (1981) 265], ears [Ann. Plast. Surg. 43 (1999) 427], lips [Plast. Reconstr. Surg. 102 (1998) 358; J. Reconstr. Microsurg. 9 (1993) 327] and nasal tips [Br. J. Oral Maxillofac. Surg. 36 (1998) 462]. Peer-reviewed evidence suggests that the survival of compromised, venous-congested tissues is improved by early application of a leech [J. Reconstr. Microsurg. 12 (1996) 165; Arch. Otolaryngol. Head Neck Surg. 114 (1988) 1395; Br. J. Plast. Surg. 45 (1992) 235]. Leeches have also recently been used to treat a wide range of conditions, including periorbital haematomas [Br. J. Ophthalmol. 75 (1991) 755], severe macroglossia [Otolaryngol. Head Neck Surg. 125 (2001) 649; J. Laryngol. Otol. 109 (1995) 442] and purpura fulminans [Ann. Plast. Surg. 35 (1995) 300]. The first medicinal leech farm, Biopharm, was set up in Swansea in 1981 by Dr Roy Sawyer, and now supplies leeches to hospitals all over the world. In this paper, we summarise the history of treatment with Hirudo medicinalis from its origin to the present day, and take a brief look at the possible future of the annelid.

  6. A Modified Single-Step Method to Repair a Central Defect of the Upper Lip.

    PubMed

    Moreno García, Carlos; González-García, Raúl; Moreno-Sánchez, Manuel; García, María Asunción Pons; Monje, Florencio

    2016-12-01

    Defects in the central region of the upper lip are difficult to repair. Several techniques have been described, many of them requiring a second surgical procedure to obtain acceptable aesthetic results. A patient with a soft defect in the central region of the upper lip following aggression by human bite is presented. To repair the defect, the principles described by Goldstein for lateral lip defects were used (Goldstein in Plast Reconstr Surg 85(3):446-452, 1990; Robotti et al. in J Plast Reconstr Aesthet Surg 63:431-439, 2010). In this particular case, two full-thickness advancing miomucosal flaps from the vermilion of the upper lip were used with predictable aesthetic results.

  7. Centrifugal Compressor Surge Controlled

    NASA Technical Reports Server (NTRS)

    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.

  8. Multicenter Clinical Trial of Keratin Biomaterials for Peripheral Nerve Regeneration

    DTIC Science & Technology

    2013-10-01

    purity (size exclusion chromatography for molecular weight, amino acids analysis, ELISA for protein identification, and gel rheology ) and 2) a cell...distribution study. Labeled keratin gel will be placed inside nerve conduits. The ends of the conduits will be closed, and the conduits will be implanted in...Marra KG. Keratin gel filler for peripheral nerve repair in a rodent sciatic nerve injury model. Plast Reconstr Surg 2012;129:67-78. Pace LA

  9. Microvascular Reconstructive Surgery in Operations Iraqi and Enduring Freedom: the US Military Experience Performing Free Flaps in a Combat Zone

    DTIC Science & Technology

    2013-01-01

    Minor complications occurred in six patients, including venous congestion requiring throm- bectomy (3), partial flap loss, donor site hematoma , and...internal- fixation of a comminuted radial fracture . (B), After inset of an anterolateral thigh free flap, the most proximal portion of the injury is...for reconstruction of acute open tibial fractures : timing of coverage and long-term functional results. Plast Reconstr Surg. 1992;89:478. 12. Heller L

  10. Investigation of Severe Craniomaxillofacial Battle Injuries Sustained by U.S. Service Members: A Case Series

    DTIC Science & Technology

    2012-11-05

    Polytrauma injuries so severe as to prevent comprehensive treatment of CMF injuries • Severe traumatic brain injuries Based on these criteria, four...and Enduring Freedom (OIF/OEF explosion burns). Burns 2006;32; 853 857 5 Motamedi MH. Primary treatment of penetrating injuries to the face. J Oral...an algorithm for primary reconstruction. Plast Reconstr Surg 1996;98:583 601 7 Ueeck BA. Penetrating injuries to the face: delayed versus primary

  11. Pressure surge attenuator

    DOEpatents

    Christie, Alan M.; Snyder, Kurt I.

    1985-01-01

    A pressure surge attenuation system for pipes having a fluted region opposite crushable metal foam. As adapted for nuclear reactor vessels and heads, crushable metal foam is disposed to attenuate pressure surges.

  12. Incorporating multi-source feedback into a new clinically based revision course for the FRCS(Plast) exam.

    PubMed

    Chipp, Elizabeth; Srinivasan, Karthik; Khan, Muhammad Adil Abbas; Rayatt, Sukh

    2011-01-01

    Exit exams for completion of surgical training are demanding and have relatively low pass rates with many candidates requiring multiple attempts. To establish a new, clinically based exam preparation course, utilising multi-source feedback, to identify candidates at risk of failure and improve pass rates. We describe the process of establishing a new, unique, clinically based exam preparation course incorporating multi-source feedback from examiners, patients, nurses and other trainees. We present the course results as well as the exam results for each candidate and analyse the results of the multi-source feedback. Nine candidates have so far successfully completed both the preparation course and the FRCS(Plast) exam. Success in the exam preparation course accurately predicts success in the FRCS(Plast) exam. Nursing staff and patients tend to give higher scores than examiners and trainees. The majority of marginal failures from the course went on to pass the exam, indicating that the course allows candidates to successfully address weaknesses identified on the course. A clinically based exam preparation course utilising multi-source feedback allows identification of candidates at risk of failing a surgical training exit exam and allows targeted training in order to maximise pass rates.

  13. Compressor surge counter

    DOEpatents

    Castleberry, Kimberly N.

    1983-01-01

    A surge counter for a rotating compressor is provided which detects surging by monitoring the vibration signal from an accelerometer mounted on the shaft bearing of the compressor. The circuit detects a rapid increase in the amplitude envelope of the vibration signal, e.g., 4 dB or greater in less than one second, which is associated with a surge onset and increments a counter. The circuit is rendered non-responsive for a period of about 5 seconds following the detection which corresponds to the duration of the surge condition. This prevents multiple registration of counts during the surge period due to rapid swings in vibration amplitude during the period.

  14. Compressor surge prevention

    SciTech Connect

    McLeister, L.

    1995-09-01

    One of the more difficult challenges facing compressor and control engineers is designing compressor control and anti-surge packages that maximize efficiency while maintaining safe compressor operating conditions. This paper focuses specifically on centrifugal compressor anti-surge philosophies. The conditions that precipitate surge in centrifugal compressors will be explored along with risk reduction techniques. Axial and reciprocating compressors have slightly different characteristics and are topics for another discussion.

  15. Storm Surge Predictability

    NASA Astrophysics Data System (ADS)

    Morss, R. E.; Fossell, K.; Ahijevych, D.; Davis, C. A.; Snyder, C.

    2016-12-01

    Storm surge is one of the most dangerous hazards of hurricanes; it results in devastating flooding and billions of dollars in damage to coastal regions and is one of the primary hurricane threats for loss of life. As such it is of great interest to better understand the probability of significant storm surge occurrence and the potential extent of impact at longer lead times to give emergency managers adequate time to plan for necessary evacuation and protective measures. This work aims to quantify the practical predictability of storm surge at various lead times and the sensitivity of the storm surge to storm parameters such as track, strength, size, and translation speed. This study also draws a distinction between inundation of a fixed region and inundation following the storm landfall location as the track varies. The latter is not usually considered, but is important for identifying particularly dangerous scenarios within the envelope of possible realizations. We quantify the predictability of storm surge from both the local and storm-following perspectives. The ADCIRC model is used to produce an ensemble of storm surge simulations. The ensemble is generated in an idealized context where the model is driven by best track data and perturbations from the best track (e.g. storm track, maximum wind, storm speed, and storm size). Inundation metrics are computed for both storm-following inundation and location-based inundation to better understand the predictive nature. While the magnitude of maximum inundation at a point is often emphasized in storm surge prediction studies, this study focuses on integrated metrics such as inundation volume and spatial extent of inundation along the coast and inland. Results will be presented from simulations of Hurricane Ike, Hurricane Charley, and a hypothetical storm that combines the size and intensity of Hurricane Charley over the track of Hurricane Ike, to demonstrate the sensitivity of inundation to a certain storm of certain

  16. Deep FIFO Surge Buffer

    NASA Technical Reports Server (NTRS)

    Temple, Gerald; Siegel, Marc; Amitai, Zwie

    1991-01-01

    First-in/first-out (FIFO) temporarily stores short surges of data generated by data-acquisition system at excessively high rate and releases data at lower rate suitable for processing by computer. Size and complexity reduced while capacity enhanced by use of newly developed, sophisticated integrated circuits and by "byte-folding" scheme doubling effective depth and data rate.

  17. Deep FIFO Surge Buffer

    NASA Technical Reports Server (NTRS)

    Temple, Gerald; Siegel, Marc; Amitai, Zwie

    1991-01-01

    First-in/first-out (FIFO) temporarily stores short surges of data generated by data-acquisition system at excessively high rate and releases data at lower rate suitable for processing by computer. Size and complexity reduced while capacity enhanced by use of newly developed, sophisticated integrated circuits and by "byte-folding" scheme doubling effective depth and data rate.

  18. The Gore-Tex Suture in Periareolar Closure: A Modified Closure Technique.

    PubMed

    Chapman, Jade; Ingram, Scott

    2016-12-01

    In breast reduction and mastopexy procedures, the periareolar closure forms a vital component of the surgery. Periareolar closures completed with an absorbable suture may be prone to significant widening, hypertrophy and/or areolar distortion. In an effort to avoid this, some surgeons use a non-absorbable/permanent suture material [Franco (Arch Plast Surg 41 (6): 728-733, 2014)]. Hammond (Plast Reconstr Surg 119 (3):804-809, 2007) recommends the use of a Gore-Tex® suture for this purpose in view of the supple, pliable nature of the material; however, there remain at least occasional instances of infection and extrusion of the knot used to tie off the Gore-Tex "purse-string" [Franco (Arch Plast Surg 41 (6): 728-733, 2014); Salgarello (Aesthet Plast Surg 37 (5):1061-1062, 2013)]. We describe a method of securing the suture ends, which avoids the creation of a bulky knot, thus minimising the risk of infection and suture extrusion. Level of Evidence V This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

  19. Surge-damping vacuum valve

    DOEpatents

    Bullock, Jack C.; Kelly, Benjamin E.

    1980-01-01

    A valve having a mechanism for damping out flow surges in a vacuum system which utilizes a slotted spring-loaded disk positioned adjacent the valve's vacuum port. Under flow surge conditions, the differential pressure forces the disk into sealing engagement with the vacuum port, thereby restricting the flow path to the slots in the disk damping out the flow surge.

  20. Communicating Storm Surge Forecast Uncertainty

    NASA Astrophysics Data System (ADS)

    Troutman, J. A.; Rhome, J.

    2015-12-01

    When it comes to tropical cyclones, storm surge is often the greatest threat to life and property along the coastal United States. The coastal population density has dramatically increased over the past 20 years, putting more people at risk. Informing emergency managers, decision-makers and the public about the potential for wind driven storm surge, however, has been extremely difficult. Recently, the Storm Surge Unit at the National Hurricane Center in Miami, Florida has developed a prototype experimental storm surge watch/warning graphic to help communicate this threat more effectively by identifying areas most at risk for life-threatening storm surge. This prototype is the initial step in the transition toward a NWS storm surge watch/warning system and highlights the inundation levels that have a 10% chance of being exceeded. The guidance for this product is the Probabilistic Hurricane Storm Surge (P-Surge) model, which predicts the probability of various storm surge heights by statistically evaluating numerous SLOSH model simulations. Questions remain, however, if exceedance values in addition to the 10% may be of equal importance to forecasters. P-Surge data from 2014 Hurricane Arthur is used to ascertain the practicality of incorporating other exceedance data into storm surge forecasts. Extracting forecast uncertainty information through analyzing P-surge exceedances overlaid with track and wind intensity forecasts proves to be beneficial for forecasters and decision support.

  1. Svalbard surging glacier landsystems

    NASA Astrophysics Data System (ADS)

    Lovell, Harold; Benn, Douglas; Lukas, Sven; Flink, Anne

    2014-05-01

    The percentage of Svalbard glaciers thought to be of surge-type is somewhere between 13-90% according to different sources variously based on statistical analysis and observations of diagnostic glaciological and geomorphological features, e.g. looped moraines. Developing a better understanding of which of these figures, if either, is most realistic is important in the context of glacier dynamics and related contributions of small glaciers and ice caps to sea level change in the immediate future. We present detailed geomorphological assessments of the margins of several known surge-type glaciers in Svalbard in order to update and improve the existing framework by which they are identified, and to provide a foundation for future reassessments of the surge-type glacier population based on distinct landform-sediment assemblages. Three landsystems are proposed: (1) Surges of small valley glaciers produce a prominent ice-cored latero-frontal moraine at their surge maximum and are characterised by an inner zone of ice stagnation terrain (hummocky topography, kettle lakes, debris flows) with no or only very few poorly-defined bedforms (crevasse squeeze ridges, eskers and flutes) and no recessional moraines. Many of these glaciers may have surged in the past but show no signs that they have the capability to do so again in the future. (2) Larger land-terminating glaciers, often with several tributaries, typically produce a push moraine complex which contains evidence for multiple advances, as identified from ridge-meltwater channel relationships. The inner zone often contains a large lagoon, partly dammed by the push moraine complex, and widespread ice stagnation terrain. Crevasse squeeze ridges, eskers and flutes are well-defined but small and limited in number and distribution. (3) Surges of large tidewater glaciers produce distinctive, often multi-generational, landform assemblages both in submarine and lateral terrestrial positions. The well-preserved submarine record

  2. How do glaciers surge? A review

    NASA Astrophysics Data System (ADS)

    Raymond, Charles F.

    1987-08-01

    The results of observations bearing on the fast motion during a glacial surge are discussed. The characteristics of the surge cycle are described, and the processes of surge behavior are examined, including the basic mechanisms of surge motion, the role of longitudinal stress gradients in surge motion, constraints on sliding behavior during surge motion, initiation and termination of surge motion. Unresolved questions concerning bed structure, sliding process, basal water flow, and surges are addressed.

  3. Demand surge following earthquakes

    USGS Publications Warehouse

    Olsen, Anna H.

    2012-01-01

    Demand surge is understood to be a socio-economic phenomenon where repair costs for the same damage are higher after large- versus small-scale natural disasters. It has reportedly increased monetary losses by 20 to 50%. In previous work, a model for the increased costs of reconstruction labor and materials was developed for hurricanes in the Southeast United States. The model showed that labor cost increases, rather than the material component, drove the total repair cost increases, and this finding could be extended to earthquakes. A study of past large-scale disasters suggested that there may be additional explanations for demand surge. Two such explanations specific to earthquakes are the exclusion of insurance coverage for earthquake damage and possible concurrent causation of damage from an earthquake followed by fire or tsunami. Additional research into these aspects might provide a better explanation for increased monetary losses after large- vs. small-scale earthquakes.

  4. High conductance surge cable

    DOEpatents

    Murray, M.M.; Wilfong, D.H.; Lomax, R.E.

    1998-12-08

    An electrical cable for connecting transient voltage surge suppressors to electrical power panels. A strip of electrically conductive foil defines a longitudinal axis, with a length of an electrical conductor electrically attached to the metallic foil along the longitudinal axis. The strip of electrically conductive foil and the length of an electrical conductor are covered by an insulating material. For impedance matching purposes, triangular sections can be removed from the ends of the electrically conductive foil at the time of installation. 6 figs.

  5. High conductance surge cable

    DOEpatents

    Murray, Matthew M.; Wilfong, Dennis H.; Lomax, Ralph E.

    1998-01-01

    An electrical cable for connecting transient voltage surge suppressers to ectrical power panels. A strip of electrically conductive foil defines a longitudinal axis, with a length of an electrical conductor electrically attached to the metallic foil along the longitudinal axis. The strip of electrically conductive foil and the length of an electrical conductor are covered by an insulating material. For impedance matching purposes, triangular sections can be removed from the ends of the electrically conductive foil at the time of installation.

  6. Heterogeneity in Karakoram glacier surges

    NASA Astrophysics Data System (ADS)

    Quincey, Duncan J.; Glasser, Neil F.; Cook, Simon J.; Luckman, Adrian

    2015-07-01

    Many Karakoram glaciers periodically undergo surges during which large volumes of ice and debris are rapidly transported downglacier, usually at a rate of 1-2 orders of magnitude greater than during quiescence. Here we identify eight recent surges in the region and map their surface velocities using cross-correlation feature tracking on optical satellite imagery. In total, we present 44 surface velocity data sets, which show that Karakoram surges are generally short-lived, lasting between 3 and 5 years in most cases, and have rapid buildup and relaxation phases, often lasting less than a year. Peak velocities of up to 2 km a-1 are reached during summer months, and the surges tend to diminish during winter months. Otherwise, they do not follow a clearly identifiable pattern. In two of the surges, the peak velocity travels down-ice through time as a wave, which we interpret as a surge front. Three other surges are characterized by high velocities that occur simultaneously across the entire glacier surface, and acceleration and deceleration are close to monotonic. There is also no consistent seasonal control on surge initiation or termination. We suggest that the differing styles of surge can be partly accounted for by individual glacier configurations and that while some characteristics of Karakoram surges are akin to thermally controlled surges elsewhere (e.g., Svalbard), the dominant surge mechanism remains unclear. We thus propose that these surges represent a spectrum of flow instabilities and the processes controlling their evolution may vary on a glacier by glacier basis.

  7. The Relevance of Hyperbaric Oxygen to Combat Medicine

    DTIC Science & Technology

    2001-06-01

    oxygen and multiple skin allografis on the healing of skin wounds. Surgery 62: 1051-1058, 1967. 10 Bowersox, J. C ., Strauss, M. B., and Hart, G . B...skin grafts, Lancet 1967 Apr 22: 868-87 1. 7 McFarlane, R. M., Wermuth , R. E., The use of hyperbaric oxygen to prevent necrosis in experimental...oxygen and pedicle flaps, skin grafts, and burns. Plast. Reconstr. Surg. 45: 24-30, 1970 9 Shulman, A. G ., and Krohn, H. L. Influence of hyperbaric

  8. Pediatric nasal fractures: evaluation and management.

    PubMed

    Desrosiers, Arthur E; Thaller, Seth R

    2011-07-01

    Nasal fractures have been reported as 1 of the 3 most commonly encountered pediatric facial bone fractures. The most common causes of nasal fractures in this age group are auto accidents (40%), sports injuries (25%), intended injuries (15%), and home injuries (10%). Nasal fractures are usually treated with closed reduction (Higuera S, Lee EI, Stal S. Nasal trauma and the deviated nose. Plast Reconstr Surg 2007;120:64S-75S). This results in a significant incidence of posttraumatic deformities, often requiring secondary surgical treatment. For this reason, it is paramount to pay careful attention to the underlying structural nasal anatomy during the initial diagnosis and management.

  9. Surge in the Ring

    NASA Image and Video Library

    2016-08-29

    An ethereal, glowing spot appears on Saturn's B ring in this view from NASA's Cassini spacecraft. There is nothing particular about that place in the rings that produces the glowing effect -- instead, it is an example of an "opposition surge" making that area on the rings appear extra bright. An opposition surge occurs when the Sun is directly behind the observer looking toward the rings. The particular geometry of this observation makes the point in the rings appear much, much brighter than would otherwise be expected. This view looks toward the sunlit side of the rings from about 28 degrees above the ring plane. The image was taken in visible light with the Cassini wide-angle camera on June 26, 2016. The view was acquired at a distance of approximately 940,000 miles (1.5 million kilometers) from the rings and at a Sun-ring-spacecraft, or phase, angle of 0 degrees. Image scale on the rings at center is 56 miles (90 kilometers) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA20496

  10. Ceres During Opposition Surge.

    NASA Image and Video Library

    2017-05-16

    NASA's Dawn spacecraft successfully observed Ceres at opposition on April 29, 2017, taking images from a position exactly between the sun and Ceres' surface. Mission specialists had carefully maneuvered Dawn into a special orbit so that the spacecraft could view Occator Crater, which contains the brightest area of Ceres, from this new perspective. A movie shows these opposition images, with contrast enhanced to highlight brightness differences. The bright spots of Occator stand out particularly well on an otherwise relatively bland surface. Dawn took these images from an altitude of about 12,000 miles (20,000 kilometers). Based on data from ground-based telescopes and spacecraft that have previously viewed planetary bodies at opposition, scientists predicted that Ceres would appear brighter from this opposition configuration. This increase in brightness, or "surge," relates the size of the grains of material on the surface, as well as how porous those materials are. The science motivation for performing these observations is further explained in the March 2017 issue of the Dawn Journal blog. A movie can be viewed at https://photojournal.jpl.nasa.gov/catalog/PIA21405

  11. 7 CFR 58.218 - Surge tanks.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Surge tanks. 58.218 Section 58.218 Agriculture....218 Surge tanks. If surge tanks are used for hot milk, and temperatures of product including foam being held in the surge tank during processing, is not maintained at a minimum of 150 °F, then two...

  12. Laboratory animal research published in plastic surgery journals in 2014 has extensive waste: A systematic review.

    PubMed

    Freshwater, M Felix

    2015-11-01

    Laboratory animal research must be designed in a manner that minimizes bias if it is to yield valid and reproducible results. In 2009, a survey that examined 271 animal studies found that 87% did not use randomization and 86% did not use blinding. This has been called "research waste" because it wasted time and resources. This systematic review measured the quantity of research waste in plastic surgery journals in 2014. The PRISMA-P protocol was used. SCOPUS and PubMed searches were done for all animal studies published in 2014 in Aesthetic Plast Surg, Aesthet Surg J, Ann Plast Surg, JPRAS, J Plast Surg Hand Surg and Plast Reconstr Surg. These were supplemented by manual searches of the 2014 issues not indexed. Articles were analyzed for descriptions of randomization, randomization methodology, allocation concealment, and blinding of the primary outcome assessment. Corresponding authors who mentioned randomization without elaborating were emailed for details. 112 of 154 articles met the inclusion criteria. Only 24/112 (21.4%) had blinding of the primary outcome measure, 28/110 (25.5%) of articles that required randomization mentioned it. While 12/28 articles clearly described randomizing the intervention, only 4/28 described the method of randomization, and 2/28 mentioned allocation concealment. Only two authors responded and described the randomization methodology. The quality of plastic surgery laboratory animal research published in 2014 was poor. Use of the National Centre for the Replacement Refinement & Reduction of Animals in Research's "Animal Research: Reporting In Vivo Experiments" (ARRIVE) Guidelines by authors, and enforcement of them by editors and reviewers could improve research quality and reduce waste. Copyright © 2015 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  13. Sputtering, Surging Sun [HD Video

    NASA Image and Video Library

    2017-09-27

    STEREO (Ahead) caught the action as one edge of a single active region spurted out more than a dozen surges of plasma in less than two days (Feb. 15-16, 2010). As seen in extreme UV light, the surges were narrow and directional outbursts driven by intense magnetic activity in the active region. While these kinds of outbursts have been observed numerous times, it was the frequency of so many surges in a short span of time that caught our attention. In this wavelength of UV light we are seeing singly ionized Helium at about 60,000 degrees C. For more information: stereo.gsfc.nasa.gov/ Credit: NASA/GSFC/STEREO To learn more about NASA's Sun Earth Day go here: sunearthday.nasa.gov/2010/index.php

  14. Fitting Surge Functions to Data

    ERIC Educational Resources Information Center

    Gordon, Sheldon P.

    2006-01-01

    The problem of fitting a surge function to a set of data such as that for a drug response curve is considered. A variety of different techniques are applied, including using some fundamental ideas from calculus, the use of a CAS package, and the use of Excel's regression features for fitting a multivariate linear function to a set of transformed…

  15. Surge bin retorting solid feed material

    SciTech Connect

    Kennedy, C.R.; Krambeck, F.J.

    1984-11-06

    An improved surge bin for a Lurgi-Ruhrgas process has baffles which promote uniform flow of feed material through the surge bin. Improved retorting of kerogen from oil shale is obtained. Stripping gas such as steam, is supplied to the surge bin. A separator has a large disengaging volume to remove entrained solid particles and improve the quality of the hydrocarbon product.

  16. The worst moment of superposed surge wave in upstream series double surge tanks of hydropower station

    NASA Astrophysics Data System (ADS)

    Teng, Y.; Yang, J. D.; Guo, W. C.; Chen, J. P.

    2016-11-01

    It is a consensus to consider the superposed working conditions when calculating the surge wave in surge tank of hydropower station with long diversion tunnel. For the hydropower station with single surge tank, the method of determining the worst superposed moment is mature. However, for the hydropower station with upstream series double surge tanks, research in this field is still blank. Based on an engineering project, this paper investigated the worst moments and the control superposed working conditions about the maximum surge level and the minimum surge level of upstream series double surge tanks using numerical simulation. In addition, the incidence relations between the worst moment of superposed surge wave and the different areal array and distance between the two surge tanks are also carried out. The results showed that: With the decrease of the distance between auxiliary surge tank and upstream reservoir, the maximum values of the highest surge levels in the two surge tanks always reach close to but a little earlier than the bigger one time when the inflowing discharges of the two surge tanks reach the maximum. It is similar to the minimum values of lowest surge levels in the two surge tanks which also reach close to but a little later than the bigger one time when the outflowing discharges of the two surges reach the maximum. Moreover, the closer the area of auxiliary surge tank to the area of main surge tank is, the closer the worst moment to the bigger one time when inflow or outflow of the two surges reach the maximum will become.

  17. Observing storm surges from satellite altimetry

    NASA Astrophysics Data System (ADS)

    Han, Guoqi

    2016-07-01

    Storm surges can cause catastrophic damage to properties and loss of life in coastal communities. Thus it is important to enhance our capabilities of observing and forecasting storm surges for mitigating damage and loss. In this presentation we show examples of observing storm surges around the world using nadir satellite altimetry, during Hurricane Sandy, Igor, and Isaac, as well as other cyclone events. The satellite observations are evaluated against tide-gauge observations and discussed for dynamic mechanisms. We also show the potential of a new wide-swath altimetry mission, the Surface Water and Ocean Topography (SWOT), for observing storm surges.

  18. Probabilistic Extra-Tropical Storm Surge Guidance

    NASA Astrophysics Data System (ADS)

    Liu, H.; Taylor, A. A.

    2016-02-01

    The National Weather Service's (NWS) Meteorological Development Laboratory (MDL) developed the Extra-Tropical Storm Surge (ETSS) model in 1995 by applying the Sea Lake and Overland Surges from Hurricanes (SLOSH) model to Extra-Tropical storms. Over the last two years, MDL, with Hurricane Sandy Supplemental funding, has enhanced the ETSS model to meet the anticipated requirements of a potential extra-tropical storm surge watch. The latest such enhancement, implemented in October 2015, enabled ETSS to operationally provide deterministic inundation guidance four times a day based on storm surge and tide in all of its model domains. Storm surge guidance has various uncertainties associated with it such as (a) the atmospheric forcing (wind speed, wind direction and atmospheric pressure), (b) the initial water conditions, (c) the included physical processes, (d) the numerical scheme, etc. While some of these can be reduced by enhancing the storm surge model, others, such as atmospheric forcing, rely on external inputs. Uncertainty in atmospheric forcing is particularly challenging as it is the main source of uncertainty in storm surge based inundation guidance. Ensemble techniques are necessary to produce quantitative estimates of storm surge based inundation risk. To create such an ensemble technique, MDL has developed the Probabilistic Extra-Tropical Storm Surge (PETSS) model by using atmospheric inputs from the 21 Global Ensemble Forecast System ensemble members. This paper describes the details of this effort and provides statistical verification of the PETSS products for several case studies.

  19. Global warming and extreme storm surges

    NASA Astrophysics Data System (ADS)

    Grinsted, Aslak

    2013-04-01

    I will show empirical evidence for how global warming has changed extreme storm surge statistics for different regions in the world. Are there any detectable changes beyond what we expect from sea level rise. What does this suggest about the future of hurricane surges such as from hurricane Katrina and superstorm Sandy?

  20. A Global Database of Tropical Storm Surges

    NASA Astrophysics Data System (ADS)

    Needham, Hal F.; Keim, Barry D.; Sathiaraj, David; Shafer, Mark

    2013-06-01

    Tropical cyclone-generated storm surges are among the world's most deadly and costly natural disasters. The destructive nature of this hazard was clearly seen last fall, as Hurricane Sandy generated a devastating storm surge along the mid-Atlantic coast. The storm killed 147 people and caused approximately $50 billion in economic losses [Blake et al., 2012].

  1. 7 CFR 58.218 - Surge tanks.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... AGRICULTURAL MARKETING ACT OF 1946 AND THE EGG PRODUCTS INSPECTION ACT (CONTINUED) GRADING AND INSPECTION, GENERAL SPECIFICATIONS FOR APPROVED PLANTS AND STANDARDS FOR GRADES OF DAIRY PRODUCTS 1 General....218 Surge tanks. If surge tanks are used for hot milk, and temperatures of product including...

  2. 7 CFR 58.218 - Surge tanks.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... AGRICULTURAL MARKETING ACT OF 1946 AND THE EGG PRODUCTS INSPECTION ACT (CONTINUED) GRADING AND INSPECTION, GENERAL SPECIFICATIONS FOR APPROVED PLANTS AND STANDARDS FOR GRADES OF DAIRY PRODUCTS 1 General....218 Surge tanks. If surge tanks are used for hot milk, and temperatures of product including...

  3. Development and Evaluation of Storm Surge Ensemble Forecasting for the Philippines Using JMA Storm Surge Model

    NASA Astrophysics Data System (ADS)

    Lapidez, J. P. B.; Tablazon, J. P.; Lagmay, A. M. F. A.; Suarez, J. K. B.; Santiago, J. T.

    2014-12-01

    The Philippines is one of the countries most vulnerable to storm surge. It is located in the North-western Pacific basin which is the most active basin in the planet. An average of 20 tropical cyclones enters the Philippine area of responsibility (PAR) every year. The archipelagic nature of the country with regions having gently sloping coasts and shallow bays also contribute to the formation of extreme surges. Last November 2013, storm surge brought by super typhoon Haiyan severely damaged several coastal regions in the Visayan Islands. Haiyan left more than 6 300 casualties and damages amounting to more than $ 2 billion. Extreme storm surge events such as this highlight the need to establish a storm surge early warning system for the country. This study explores the development and evaluation of storm surge ensemble forecasting for the Philippines using the Japan Meteorological Agency (JMA) storm surge model. 36-hour, 24-hour, and 12-hour tropical cyclone forecasts are used to generate an ensemble storm surge forecast to give the most probable storm surge height at a specific point brought by an incoming tropical cyclone. The result of the storm surge forecast is compared to tide gauge record to evaluate the accuracy. The total time of computation and dissemination of forecast result is also examined to assess the feasibility of using the JMA storm surge model for operational purposes.

  4. Storm Surge Modeling with CYGNSS Winds

    NASA Astrophysics Data System (ADS)

    Ruf, C. S.; Warnock, A. M.

    2016-12-01

    Hurricane storm surge is a problem of growing importance due to increasing population density along the coasts, rising sea levels, and the possibility of greater frequency and severity of storm occurrence. Storm surge modeling can provide guidance for warning and evacuation systems. However, modeling accuracy, particularly with respect to the intensity forecast (as opposed to storm track) is limited by a lack of high resolution meteorological data. Currently, methods of data collection within a tropical cyclone's eyewall are limited to `hurricane hunter' type aircraft and dropsondes. Neither of these methods can provide the needed temporal and spatial data sampling necessary for accurate storm surge forecasting. We examine the potential to improve storm surge forecast skill using simulated, high-temporal resolution remote sensing data products from NASA's Cyclone Global Navigation Satellite System (CYGNSS) mission. We present and compare ADCIRC 2DDI storm surge hindcasting results of Hurricane Irene using four meteorological forcing scenarios: 1) "True" meteorological data obtained from HWRF reanalysis runs; 2) "Worst-case forecast" using low-resolution NOGAPS forecast wind and pressures; 3) "Best-case forecast" using high-resolution HWRF forecast winds and pressures; and 4) a simulated "CYGNSS forecast" with wind field given by a parameterized model trained using CYGNSS-derived values for the maximum wind speed and radius of maximum winds. The results suggest that the increased spatial and temporal resolution of the CYGNSS-derived winds have a positive impact on storm surge modeling predictions and that the mission's data products will improve storm surge forecasts.

  5. Storm surge and tidal range energy

    NASA Astrophysics Data System (ADS)

    Lewis, Matthew; Angeloudis, Athanasios; Robins, Peter; Evans, Paul; Neill, Simon

    2017-04-01

    The need to reduce carbon-based energy sources whilst increasing renewable energy forms has led to concerns of intermittency within a national electricity supply strategy. The regular rise and fall of the tide makes prediction almost entirely deterministic compared to other stochastic renewable energy forms; therefore, tidal range energy is often stated as a predictable and firm renewable energy source. Storm surge is the term used for the non-astronomical forcing of tidal elevation, and is synonymous with coastal flooding because positive storm surges can elevate water-levels above the height of coastal flood defences. We hypothesis storm surges will affect the reliability of the tidal range energy resource; with negative surge events reducing the tidal range, and conversely, positive surge events increasing the available resource. Moreover, tide-surge interaction, which results in positive storm surges more likely to occur on a flooding tide, will reduce the annual tidal range energy resource estimate. Water-level data (2000-2012) at nine UK tide gauges, where the mean tidal amplitude is above 2.5m and thus suitable for tidal-range energy development (e.g. Bristol Channel), were used to predict tidal range power with a 0D modelling approach. Storm surge affected the annual resource estimate by between -5% to +3%, due to inter-annual variability. Instantaneous power output were significantly affected (Normalised Root Mean Squared Error: 3%-8%, Scatter Index: 15%-41%) with spatial variability and variability due to operational strategy. We therefore find a storm surge affects the theoretical reliability of tidal range power, such that a prediction system may be required for any future electricity generation scenario that includes large amounts of tidal-range energy; however, annual resource estimation from astronomical tides alone appears sufficient for resource estimation. Future work should investigate water-level uncertainties on the reliability and

  6. Using a new Storm Surge Index to Evaluate Changes in Surge Associated With Possible Climate Changes

    NASA Astrophysics Data System (ADS)

    Clayson, C. A.

    2008-05-01

    I will be discussing the creation of a new storm surge index that incorporates many variables important in storm surge generation like maximum winds, radius of maximum winds, pressure, translation speed, and bathymetry. Using a two-dimensional, barotropic ocean model, power laws have been developed that describe the relationship between storm surge and changes in maximum wind, radius of maximum wind, pressure, and bathymetry. Direct curve fitting is used to describe the relationship between storm surge and changes in translation speed since a power-law relationship does not exist in that case. Comparisons of this storm surge index with a database of landfalling, United States hurricanes between 1986 and 2007 with associated storm parameters and observed maximum storm surges will be shown. The quality of the storm surge index is verified using correlation analysis between the storm surge index and the observed maximum storm surges. I will then discuss possible future changes in storm surge along the eastern seaboard and the Gulf of Mexico associated with varying changes in sea level, and changes in hurricane size and intensity.

  7. MOV surge arresters: improved substation equipment protection

    SciTech Connect

    Niebuhr, W.D.

    1985-07-01

    The introduction of metal-oxide-varistor (MOV) surge arresters has added a new dimension to substation equipment protection. Through the optimal use of these arresters, it is possible to lower surge arrester ratings and thereby improve protective margins, resulting in a possible reduction of the insulation levels (BIL) of substation equipment. This reduction in BIL can lead to a significant reduction in the cost of substation equipment. General methods are delineated for selecting MOV surge arresters for substation protection and the resulting effect on substation equipment insulation levels.

  8. The role of full-thickness skin grafting and steroid injection in the treatment of auricular keloids.

    PubMed

    Brown, Nefertiti A; Ortega, F Raymond

    2010-05-01

    Keloids are a response to wound healing that occurs due to hyperproliferation of dermal collagen in response to skin injury (Olabanji et al, Surg Pract. 2005;9:2-7). Multiple modalities have been described in the literature to target these lesions, but treatment and prevention remain a challenge because of the high rate of recurrence (Brissett and Sherris, Facial Plast Surg. 2001;17:263-272; Kelly, Dermatol Ther. 2004;17:212-218; Robles and Berg, Clin Dermatol. 2007;25:26-32; Porter, Otolaryngol Clin North Am. 2002;35:207-220, viii). We studied the rate of recurrence of auricular keloids through a technique previously described in the literature (Converse and Stallings, Plast Reconstr Surg. 1972;49:461-463), but over a series of patients. Keloids were treated with total excision in combination with coverage of the resulting defect with a full-thickness skin graft and intradermal injection of triamcinolone acetonide solution at the periphery of the donor and recipient sites. From April 2006 to February 2007, 10 patients with auricular keloids were done using this technique, and during an 11-month follow-up no recurrence was observed. These results support that full-thickness skin grafts can be used to address keloid lesions without recurrence.

  9. Physical attributes of hurricane surges and their role in surge warning

    NASA Astrophysics Data System (ADS)

    Irish, J. L.

    2012-12-01

    In the last decade, the US has experienced some of its largest surges and hurricane-related damages on record. Effective evacuation in advance of a hurricane strike requires accurate estimation of the hurricane surge hazard that effectively conveys risk not only to government decision makers but also to the general public. Two primary challenges exist with the current structure for surge warning. First, existing computational methods for developing accurate, quantitative surge forecasts, namely surge height and inundation estimation, are limited by time and computational resources. Second, due primarily to the popularity and wide use of the Saffir-Simpson wind scale to convey the complete hurricane hazard, the public's perception of surge hazard is inaccurate. Here, we use dimensionless scaling and hydrodynamics arguments to quantify the influence of hurricane variables and regional geographic characteristics on the surge response. It will be shown that hurricane surge primarily scales with the hurricane's central pressure, and size and with continental shelf width at the landfall location (Irish et al. 2009, Nat. Haz.; Song et al. in press, Nat. Haz.). Secondary influences include the hurricane's forward speed and path. The developed physical scaling is applied in two ways: (1) as a means for expanding the utility of computational simulations for real-time surge height forecasting and (2) as a means to convey relative surge hazard via a readily evaluated algebraic surge scale. In the first application, the use of this physical scaling to develop surge response functions (SRF) enables instantaneous algebraic calculation of maximum surge height at any location of interest for any hurricane meteorological condition, without loss of accuracy gained via high-resolution computational simulation. When coupled with joint probability statistics, the use of SRFs enables rapid development of continuous probability density functions for probabilistic surge forecasting (Irish

  10. Properties of the Central American cold surge

    NASA Technical Reports Server (NTRS)

    Mcguirk, James P.; Reding, Philip J.; Zhang, Yuxia

    1993-01-01

    The Central American cold surge (CACS) is a frontal incursion from the United States into Central America and resembles the East Asian cold surge. They occur more frequently than analyzed by NMC or by published results, based on our observations between 1979 and 1990. Climatology and structure are quantified, based on surface and upper air stations throughout Central America and satellite products from GOES visible and infrared sensors and SSM/I precipitable water and rain rate sensors.

  11. Major surge of the Bering Glacier

    NASA Astrophysics Data System (ADS)

    Molnia, Bruce

    Definitive evidence has been obtained in the last few weeks documenting that a new and potentially major surge of Bering Glacier is beginning. According to Bruce F. Molnia, U.S. Geological Survey, Reston, Va., and spokesperson for a USGS research group that includes Austin Post, Dennis Trabant, and Robert Krimmel, as of June 28, several hundred kilometers of the glacier were involved in the surge, displaying intensive crevassing, displaced moraines, ice overriding previously exposed bedrock, and pressure ridge development (Figure 1).

  12. Emergency department surge capacity: recommendations of the Australasian Surge Strategy Working Group.

    PubMed

    Bradt, David A; Aitken, Peter; Fitzgerald, Gerry; Swift, Roger; O'Reilly, Gerard; Bartley, Bruce

    2009-12-01

    For more than a decade, emergency medicine (EM) organizations have produced guidelines, training, and leadership for disaster management. However, to date there have been limited guidelines for emergency physicians (EPs) needing to provide a rapid response to a surge in demand. The aim of this project was to identify strategies that may guide surge management in the emergency department (ED). A working group of individuals experienced in disaster medicine from the Australasian College for Emergency Medicine Disaster Medicine Subcommittee (the Australasian Surge Strategy Working Group) was established to undertake this work. The Working Group used a modified Delphi technique to examine response actions in surge situations and identified underlying assumptions from disaster epidemiology and clinical practice. The group then characterized surge strategies from their corpus of experience; examined them through available relevant published literature; and collated these within domains of space, staff, supplies, and system operations. These recommendations detail 22 potential actions available to an EP working in the context of surge, along with detailed guidance on surge recognition, triage, patient flow through the ED, and clinical goals and practices. The article also identifies areas that merit future research, including the measurement of surge capacity, constraints to strategy implementation, validation of surge strategies, and measurement of strategy impacts on throughput, cost, and quality of care.

  13. Correction of recurrent inverted nipples with the Sakai method.

    PubMed

    Taneda, Hiroko; Sakai, Shigemi; Kamei, Chihiro

    2013-08-01

    An inverted nipple is a congenital condition that can be corrected with established surgical methods, although recurrence sometimes occurs. The correction of recurrent inverted nipples is challenging because of scars and fibrosis caused by previous surgical treatments. The authors treated 14 patients with 25 recurrent inverted nipples with the Sakai method. All patients were observed for more than 6 months. All of the resulting nipples were acceptable and fit into the normal nipple shapes described by Kim et al (Plast Reconstr Surg. 2006;118:1526-1531) (ie, rectangular, omega, round, cap, or slanting). Although the Sakai method is not new, it may be a useful option not only for ordinary inverted nipples but also for the correction of recurrent inverted nipples.

  14. Classification of congenital nasal deformities: a proposal to amend the existing classification.

    PubMed

    Fijałkowska, Marta; Antoszewski, Bogusław

    2017-03-01

    Congenital nasal anomalies are rare malformations with a broad spectrum of defects. The only existing classification strictly relating to nasal anomalies was presented by Losee et al. (Plast Reconstr Surg 113(2):676-689, 2004). The aim of this paper is to propose some suggestions, based on our current knowledge and experience gained by treating our patients in the clinic, in creating a specification of patients with congenital nasal anomalies. All patients with congenital nose defects treated in our health center were selected for this study. The research was retrospective and included years from 1995 to 2015. Nasal anomaly associated with cleft lip and palate was excluded. Patients were classified into four categories of congenital nasal anomalies, according to Losee et al.

  15. Pattern of healing of calvarial bone in the rat following application of the erbium-YAG laser.

    PubMed

    el Montaser, M A; Devlin, H; Sloan, P; Dickinson, M R

    1997-01-01

    The aim of this study was to examine the pattern of healing in rat calvarial defects prepared with the erbium-YAG laser, using the "guided tissue regeneration" technique [Dahlin et al., Scand J Plast Reconstr Hand Surg 1990;24: 13-19]. PTFE membranes were placed over the lased skull defects and the skin wounds sutured. Rats were killed humanely at intervals after surgery and the skulls processed for paraffin wax histology. A further group of mature rats was killed humanely and the calvariae removed. Slots were prepared using the erbium-YAG laser and immediately examined under the environmental scanning electron microscope (ESEM) in hydrated conditions, which avoided drying artefact. An amorphous, mineral-rich carbon layer surrounds the lased bone defect, which in the in vivo experiments was seen as a basophilic zone that was resistant to resorption. Bone infilling of the lased defect was retarded by delayed resorption of the amorphous, mineral-rich carbon layer.

  16. Base surge in recent volcanic eruptions

    USGS Publications Warehouse

    Moore, J.G.

    1967-01-01

    A base surge, first identified at the Bikini thermonuclear undersea explosion, is a ring-shaped basal cloud that sweeps outward as a density flow from the base of a vertical explosion column. Base surges are also common in shallow underground test explosions and are formed by expanding gases which first vent vertically and then with continued expansion rush over the crater lip (represented by a large solitary wave in an underwater explosion), tear ejecta from it, and feed a gas-charged density flow, which is the surge cloud. This horizontally moving cloud commonly has an initial velocity of more than 50 meters per second and can carry clastic material many kilometers. Base surges are a common feature of many recent shallow, submarine and phreatic volcanic eruptions. They transport ash, mud, lapilli, and blocks with great velocity and commonly sandblast and knock down trees and houses, coat the blast side with mud, and deposit ejecta at distances beyond the limits of throw-out trajectories. Close to the eruption center, the base surge can erode radial channels and deposit material with dune-type bedding. ?? 1967 Stabilimento Tipografico Francesco Giannini & Figli.

  17. Electrodynamics of the westward traveling surge

    NASA Technical Reports Server (NTRS)

    Kan, J. R.; Kamide, Y.

    1985-01-01

    It is shown that the global convection pattern, the ionospheric current, and the field-aligned current associated with the westward traveling surge in the asymptotic state can be modeled quantitatively as consequences of a blockage of the Hall current from closure in the magnetosphere via field-aligned currents. The conductivity is allowed to increase self-consistently with increasing upward field-aligned current in the model. This inclusion of the self-consistent enhanced ionospheric conductivity due to discrete auroral precipitations is found to generate a localized intense westward electrojet on the poleward side of the Harang discontinuity. The westward electrojet is also found to rotate counterclockwise, merging into the eastward electrojet around the leading edge of the surge. Thus the major features of the westward traveling surge can be reproduced reasonably well in the model.

  18. 'Reverse triage' adds to surge capacity.

    PubMed

    2009-06-01

    Providing adequate surge capacity during a disaster is one of the greatest challenges of emergency response. Now, researchers have proposed a new process called "reverse triage" to help create surge capacity that otherwise would not exist. Patients who have only a slight chance of experiencing an adverse event within four days of leaving the hospital may be discharged to free bed space. ED staff can provide a daily initial reverse triage score for patients being admitted, even if a disaster is not imminent. While general guidelines can have great value, take the interests of the patient and their family into account when making discharge decisions.

  19. The Big Flood: North Sea storm surge.

    PubMed

    McRobie, Allan; Spencer, Tom; Gerritsen, Herman

    2005-06-15

    In the 50 years since the catastrophic southern North Sea storm surge of 31 January-1 February 1953, there have been technological advances in the engineering of flood protection, increased understanding of physical processes in shallow seas and estuaries, and developments in the mathematical statistics of extreme events. This introductory paper reviews how the scientific understanding of surge events, their impacts and the human responses to them is evolving on many fronts, often across disciplinary boundaries. The question of how the long-term nature of the problem itself will be influenced by possible climate, land use and policy changes is addressed, along with their associated uncertainties.

  20. Adaptive mesh refinement for storm surge

    NASA Astrophysics Data System (ADS)

    Mandli, Kyle T.; Dawson, Clint N.

    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.

  1. Computer-assisted mapping of pyroclastic surges.

    PubMed

    Malin, M C; Sheridan, M F

    1982-08-13

    Volcanic hazard maps of surge boundaries and deposit thickness can be created by using a simplified eruption model based on an "energy line" concept of pyroclastic surge and flow emplacement. Computer image-processing techniques may be used to combine three-dimensional representations of the energy relations of pyroclasts moving under the influence of gravity (defined by an "energy cone") with digital topographic models of volcanoes to generate theoretical hazard maps. The deposit boundary and thickness calculated for the 18 May 1980 eruption of Mount St. Helens are qualitatively similar to those actually observed.

  2. Storm surge and river interaction in etuaries

    NASA Astrophysics Data System (ADS)

    Maskell, J.

    2012-04-01

    In coastal areas, particularly in regions developed on estuaries, extreme river flow can combine with storm surges to present a combined hazard. This combined risk is likely to be more prominent in estuaries where fluvial fresh water input comes from catchments in hilly regions where the dependence of extreme river discharge and sea level elevation can be most statistically significant (Svensson and Jones, 2004). The risk associated with these combined coastal hazards could increase due to climate change if there were an increase in the frequency of extreme weather events. The global (IPCC, 2007) and local (Woodworth et al., 2009) rise in mean sea-level will increase the magnitude of extreme sea levels and surges will act on a higher coastal sea level and therefore increase the risk to coastal property and infrastructure. This may be associated with an increase in precipitation during extreme storm events which will have a large impact on river flooding. Therefore, the need for accurate operational forecasting of storm events will increase with the focus shifting to changes in the extreme 'tail end' of the distribution of storm events. Ideally an operational model that integrates storm surge, wave and fluvial forecasting with inundation and simulates their combined influence would be most effective for planning with respect to flood plain development, evacuation and flood defence. Current operational storm surge models are typically based on two-dimensional depth-averaged shallow water equations (Flather, 2000). Inundation models often use an approximation of the original shallow water equations which neglect the inertial terms (Prestininzi et al., 2011). These 2D flood plain inundation models are often coupled with a 1D model of the main channel of a river or estuary which permits the exchange of mass but assumes a limited exchange of momentum (Bates et al., 2005). A finite volume model (FVCOM) is used to investigate the combined influence of storm surge and river

  3. Surge discharge capability and thermal stability of a metal oxide surge arrester

    SciTech Connect

    Kan, M.; Kojima, S.; Nishiwaki, S.; Sato, T.; Yanabu, S.

    1983-02-01

    The surge discharge capability and the thermal stability of a metal oxide surge arrester were examined experimentally. It was found that the breakdown energy is nearly the same against the switching surge and the temporary overvoltage of various peak values and time durations. Heat dissipation capability of an 84kV porcelain-type model arrester was examined and found to be less than that of a small model unit, while this relation of the value had been considered opposite in a previously published paper. From these experimental data, the limit at high operation stress was found to be determined by the thermal stability rather than by the discharge capability

  4. SURGE: Smart Ultrasound Remote Guidance Experiment

    NASA Technical Reports Server (NTRS)

    Peterson, Sean

    2009-01-01

    Exploration-class missions lead to longer communication delays with mission control. May not always have communication capability to stream real-time ultrasound images. SURGE explores use of a "just-in-time" learning tool, called OPEL = On-Board Proficiency Enhancer Light as an aid to a hypothetical crew medical officer working autonomously.

  5. Research Spotlight: New method could improve hurricane surge forecasting

    NASA Astrophysics Data System (ADS)

    Tretkoff, Ernie

    2011-03-01

    In recent years, hurricanes in the Gulf of Mexico, including Katrina and Ike, caused some of the highest surges on record and significant flooding, highlighting the need for good surge forecasts that can be used for early warning and evacuation. However, current approaches for surge forecasting use models that take too much computational time or have spatial resolution too low to provide adequate forecast accuracy. Irish et al. propose a new method for determining probabilistic maximum hurricane surge forecasts. Their approach is based on calculations of surge response functions, which are derived from numerical simulations, along with analysis of meteorological forecasts. They applied the method to data from Hurricane Ike and found that they could accurately compute surge forecast probabilities within seconds, given publicly available meteorological forecast data. The method can provide a forecast of how surge would vary along the coast and identify areas most vulnerable to high surges. (Geophysical Research Letters, doi:10.1029/2010GL046347, 2011)

  6. View of Stand Pipe (Surge Tank) from FS 502. Looking ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of Stand Pipe (Surge Tank) from FS 502. Looking northeast - Childs-Irving Hydroelectric Project, Childs System, Stand Pipe (Surge Tank), Forest Service Road 708/502, Camp Verde, Yavapai County, AZ

  7. Numerical Evaluation of Storm Surge Indices for Public Advisory Purposes

    NASA Astrophysics Data System (ADS)

    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.

  8. The use of coastal altimetry to support storm surge studies in project eSurge

    NASA Astrophysics Data System (ADS)

    Cipollini, P.; Harwood, P.; Snaith, H.; Vignudelli, S.; West, L.; Zecchetto, S.; Donlon, C.

    2012-04-01

    One of the most promising applications of the new field of coastal altimetry, i.e. the discipline aiming to recover meaningful estimates of geophysical parameters (sea level, significant wave height and wind speed) from satellite altimeter data in the coastal zone, is the study of storm surges. The understanding and realistic modelling of surges supports both preparation and mitigation activities and should eventually bring enormous societal benefits, especially to some of the world's poorest countries (like Bangladesh). Earth Observation data have an important role to play in storm surge monitoring and forecasting, but the full uptake of these data by users (such as environmental agencies and tidal prediction centres) must first be encouraged by showcasing their usefulness, and then supported by providing easy access. Having recognized the above needs, The European Space Agency has recently launched a Data User Element (DUE) project called eSurge. The main purposes of eSurge are a) to contribute to an integrated approach to storm surge, wave, sea-level and flood forecasting through Earth Observation, as part of a wider optimal strategy for building an improved forecast and early warning capability for coastal inundation; and b) to increase the use of the advanced capabilities of ESA and other satellite data for storm surge applications. The project is led by Logica UK, with NOC (UK), DMI (Denmark), CMRC (Ireland) and KNMI (Netherlands) as scientific partners. A very important component of eSurge is the development, validation and provision of dedicated coastal altimetry products, which is the focus of the present contribution. Coastal altimetry has a prominent role to play as it measures the total water level envelope directly, and this is one of the key quantities required by storm surge applications and services. But it can also provide important information on the wave field in the coastal strip, which helps the development of more realistic wave models that in

  9. Earth Observation in aid of surge monitoring and forecasting: ESA's eSurge Project

    NASA Astrophysics Data System (ADS)

    Harwood, Phillip; Cipollini, Paolo; Snaith, Helen; Høyer, Jacob; Dwyer, Ned; Dunne, Declan; Stoffelen, Ad; Donlon, Craig

    2013-04-01

    The understanding and realistic modelling of surges supports both preparation and mitigation activities and should eventually bring enormous societal benefits, especially to some of the world's poorest countries. Earth Observation data from satellites have an important role to play in storm surge monitoring and forecasting, but the full uptake of these data by the users (such as environmental agencies and tidal prediction centres) must be first encouraged by showcasing their usefulness, and then supported by providing easy access. The European Space Agency has recognized the above needs and, through its Data User Element (DUE) programme, has initiated in 2011 the eSurge project, whose aims are: a) to contribute through Earth Observation to an integrated approach to storm surge, wave, sea-level and flood forecasting as part of a wider optimal strategy for building an improved forecast and warning capability for coastal inundation; and b) to increase the use of the advanced capabilities of ESA and other satellite data for storm surge applications. The project is led by Logica UK, with NOC (UK), DMI (Denmark), CMRC (Ireland) and KNMI (Netherlands) as scientific partners. eSurge aims to provide easy access to a wide range of relevant data for a range of historical surge events, as well as performing a series of experiments to demonstrate the value of this data, and running workshops and training courses to help users make use of the available data. The eSurge database of Earth Observation and in situ measurements for past surge events is now publicly available. In 2013 the project moves into its service demonstration phase, adding more data and events, including a demonstration near real time service. The project works closely with its users in order to meet their needs and to maximise the return of this data. A novel dataset provided by eSurge is coastal altimetry. Coastal altimetry has a prominent role to play as it measures directly the total water level envelope

  10. Guiding Surge Reduction Strategies via Characterization of Coastal Surge Propagation and Internal Surge Generation within a Complex Bay/Estuary System, Galveston Bay, TX

    NASA Astrophysics Data System (ADS)

    Bass, B.; Torres, J.; Irza, N.; Bedient, P. B.; Dawson, C.; Proft, J.

    2015-12-01

    In this study, Hurricane Ike (2008) and a suite of synthetic storms are simulated in order to evaluate how different hurricane landfalls, wind intensities, and radius to maximum winds influence the surge response in complex semi-enclosed bays such as Galveston Bay, located along the Texas Gulf Coast. The Advanced CIRCulation and Simulating Waves Nearshore (ADCIRC+SWAN) models are employed to quantify surge in terms of its relative coastal contributions that propagate across barrier islands and tidal inlets and subsequently into Galveston Bay, the surge generated locally within the Bay itself, and the interaction between these coastal and local components of surge. Results from this research will further the current understanding of surge interactions in bay systems and guide coastal engineering surge reduction projects that need to consider multiple lines of defense to protect complex bay/estuary systems such as Galveston Bay, TX.

  11. Taking a Closer Look at the SURGE in CounterinSURGEncy

    DTIC Science & Technology

    2010-05-03

    used in this paper. Full bibliography is available starting on page 22.) 2 Freir , Leed, and Nelson, “Iraq versus Afghanistan: A Surge Is Not a Surge...reasonable 16 Freir , Leed, and Nelson, “Iraq versus Afghanistan: A Surge Is Not a Surge Is Not a Surge...18 Freir , Leed, and Nelson, “Iraq versus Afghanistan: A Surge Is Not a Surge Is Not a Surge | Center for Strategic and

  12. Hypergravity induced prolactin surge in female rats

    NASA Technical Reports Server (NTRS)

    Megory, E.; Oyama, J.

    1985-01-01

    Acute initial exposure to hypergravity (HG) was previously found to induce prolonged diestrous in rats, which was followed by return to normal estrous cycling upon more prolonged exposure to continuous HG. Bromergocryptine was found to prevent this prolonged diestrous. In this study it is found that in female rats 20 h of 3.14 G exposure (D-1 1200 h until D-2 0800 h) can induce prolactin surge at D-2 1600 h. Shorter exposure time (8 h), or exposure during a different part of the estrous cycle (19 h: from D-1 0700 h until D-2 0200 h) could not elicit this prolactin surge. Similar exposure of male rats of HG did not alter significantly their prolactin levels. It is possible that the hypothalamus of male and female rats responds differently to stimulation by HG.

  13. Hypergravity induced prolactin surge in female rats

    NASA Technical Reports Server (NTRS)

    Megory, E.; Oyama, J.

    1985-01-01

    Acute initial exposure to hypergravity (HG) was previously found to induce prolonged diestrous in rats, which was followed by return to normal estrous cycling upon more prolonged exposure to continuous HG. Bromergocryptine was found to prevent this prolonged diestrous. In this study it is found that in female rats 20 h of 3.14 G exposure (D-1 1200 h until D-2 0800 h) can induce prolactin surge at D-2 1600 h. Shorter exposure time (8 h), or exposure during a different part of the estrous cycle (19 h: from D-1 0700 h until D-2 0200 h) could not elicit this prolactin surge. Similar exposure of male rats of HG did not alter significantly their prolactin levels. It is possible that the hypothalamus of male and female rats responds differently to stimulation by HG.

  14. Predicting the next storm surge flood

    USGS Publications Warehouse

    Stamey, B.; Wang, Hongfang; Koterba, M.

    2007-01-01

    The Virginia Institute of Marine Science (VIMS), National Weather Services (NWS) Sterling and Wakefield, Weather Forecast Offices (WFO), and the Chesapeake Bay Observing System (CBOS) jointly developed a prototype system of a regional capability to address national problem. The system was developed to integrate high-resolution atmospheric and hydrodynamic and storm surge models, evaluate the ability of the prototype to predict land inundation in the Washington, D.C., and provide flooding results to Emergency Managers (EM) using portive. The system is a potential tool for NWS WFOs to provide support to the EMs, first in the Chesapeake Bay region and then in other coastal regions by applying similar approaches in other coastal and Great Lakes regions. The Chesapeake Inundation Prediction System (CIPS) also is building on the initial prototype to predict the combined effects of storm surge and tidal and river flow inundation in the Chesapeake Bay and its tributaries.

  15. Probabilistic Storm Surge Hazard Assessment in Martinique

    NASA Astrophysics Data System (ADS)

    Krien, Yann; Dudon, Bernard; Sansorgne, Eliot; Roger, Jean; Zahibo, Narcisse; Roquelaure, Stevie

    2013-04-01

    Located at the center of the Lesser Antilles, Martinique is under the threat of hurricanes formed over the warm tropical waters of the Atlantic Ocean and Caribbean Sea. These events can be extremely costly in terms of human, property, and economic losses. Storm surge hazard studies are hence required to provide guidance to emergency managers and decision-makers. A few studies have been conducted so far in the French Lesser Antilles, but they mainly rely on scarce historical data of extreme sea levels or numerical models with coarse resolutions. Recent progress in statistical techniques for generating large number of synthetic hurricanes as well as availability of high-resolution topographic and bathymetric data (LIDAR) and improved numerical models enables us today to conduct storm surge hazard assessment studies with much more accuracy. Here we present a methodology to assess cyclonic surge hazard in Martinique both at regional and local scales. We first simulate the storm surges that would be induced by a large set of potential events generated by the statistical/deterministic models of Emanuel et al. [2006]. We use the ADCIRC-SWAN coupled models (Dietrich et al 2012) to simulate inundation inland with grid resolutions of up to 50-100m in the coastal area for the whole island.These models are validated against observations during past events such as hurricane Dean in 2007. The outputs can then be used in some specific sites to force higher resolution models for crisis management and local risk assessment studies. This work is supported by the INTERREG IV « Caribbean » program TSUNAHOULE.

  16. Pumped storage: Surge in the southeast

    SciTech Connect

    Hunt, J.M.; Hunt, R.T.

    1996-01-01

    In the past decade, there has been a surge of interest by independent power producers (IPPs) in developing pumped storage hydropower projects. However, of the 100 applicants for preliminary permits for pumped storage projects, only nine submitted license applications for development and none have been built. Two large pumped storage projects proposed by IPPs, Summit in Ohio and Mount Hope in New Jersey, received their Federal Energy Regulatory Commission (FERC) licenses in record time.

  17. Origin of the Hurricane Ike forerunner surge

    NASA Astrophysics Data System (ADS)

    Kennedy, Andrew B.; Gravois, Uriah; Zachry, Brian C.; Westerink, Joannes J.; Hope, Mark E.; Dietrich, J. Casey; Powell, Mark D.; Cox, Andrew T.; Luettich, Richard A., Jr.; Dean, Robert G.

    2011-04-01

    A large, unpredicted, water level increase appeared along a substantial section of the western Louisiana and northern Texas (LATEX) coasts 12-24 hrs in advance of the landfall of Hurricane Ike (2008), with water levels in some areas reaching 3 m above mean sea level. During this time the cyclonic wind field was largely shore parallel throughout the region. A similar early water level rise was reported for both the 1900 and the 1915 Galveston Hurricanes. The Ike forerunner anomaly occurred over a much larger area and prior to the primary coastal surge which was driven by onshore directed winds to the right of the storm track. We diagnose the forerunner surge as being generated by Ekman setup on the wide and shallow LATEX shelf. The longer forerunner time scale additionally served to increase water levels significantly in narrow-entranced coastal bays. The forerunner surge generated a freely propagating continental shelf wave with greater than 1.4 m peak elevation that travelled coherently along the coast to Southern Texas, and was 300 km in advance of the storm track at the time of landfall. This was, at some locations, the largest water level increase seen throughout the storm, and appears to be the largest freely-propagating shelf wave ever reported. Ekman setup-driven forerunners will be most significant on wide, shallow shelves subject to large wind fields, and need to be considered for planning and forecasting in these cases.

  18. Developments in centrifugal compressor surge control: A technology assessment

    NASA Astrophysics Data System (ADS)

    Botros, K. K.; Henderson, J. F.

    1994-04-01

    There are a number of surge control schemes in current use for centrifugal compressors employed in natural gas transmission systems. Basically, these schemes consist of a set of detection devices that either anticipate surge or detect it at its inception, and a set of control devices that act to prevent surge from occurring. A patent search was conducted in an attempt to assess the level and direction of technology development over the last 20 years and to define the focus for future R&D activities. In addition, the paper presents the current state of technology in three areas: surge control, surge detection, and surge suppression. Patent data obtained from on-line databases showed that most of the emphasis has been on surge control rather than on detection and control and that the current trend in surge control will likely continue toward incremental improvement of a basic or conventional surge control strategy. Various surge suppression techniques can be grouped in two categories: (i) those that are focused on better compressor interior design, and (ii) others that attempt to suppress surge by external and operational means.

  19. Statistical properties of hurricane surge along a coast

    NASA Astrophysics Data System (ADS)

    Irish, Jennifer L.; Resio, Donald T.; Divoky, David

    2011-10-01

    The validity and accuracy of approaches used to determine hurricane surge hazard risk received much attention following the hurricane seasons in mid- to late-2000, which caused record surge-related damage along the Gulf of Mexico coastline. Following Hurricane Katrina in 2005, research showed that most extreme-value statistics approaches underestimated the risk associated with this surge event. In this paper, two of the most popular methods for determining hurricane surge extreme-value statistics are reviewed: the historical surge population approach and the joint probability method. Here, it is demonstrated that both limited historical record length and random along-coast variability in hurricane landfall location can introduce significant errors into surge estimates. For example, the historical surge population approach gives errors of 9% to 17% for return periods between 50 and 1000 years when a surge record of 100 years is considered. In contrast, it is shown that the joint probability method yields significantly more reliable surge estimates, with errors of 2% to 3% for return periods between 50 and 1000 years when a storm record of 100 years is considered. Finally, we show that both methods remain robust when decadal-scale climate variability in the storm rate of occurrence is considered, so long as the hurricane history is long enough to capture the full decadal cycle. When used in conjunction with continuous surge response information, it can be concluded that the joint probability method is a practical and reliable approach for determining extreme-value hurricane surge statistics.

  20. Uncertainty in hurricane surge simulation due to land cover specification

    NASA Astrophysics Data System (ADS)

    Ferreira, Celso M.; Irish, Jennifer L.; Olivera, Francisco

    2014-03-01

    Hurricane storm surge is one of the most costly natural hazards in the United States. Numerical modeling to predict and estimate hurricane surge flooding is currently widely used for research, planning, decision making, and emergency response. Land cover plays an important role in hurricane surge numerical modeling because of its impacts on the forcing (changes in wind momentum transfer to water column) and dissipation (bottom friction) mechanisms of storm surge. In this study, the hydrodynamic model ADCIRC was used to investigate predicted surge response in bays on the central and lower Texas coast using different land cover data sets: (1) Coastal Change Analysis Program for 1996, 2001, and 2006; (2) the National Land Cover Dataset for 1992, 2001, and 2006; and (3) the National Wetlands Inventory for 1993. Hypothetical storms were simulated with varying the storm track, forward speed, central pressure, and radius to maximum wind, totaling 140 simulations. Data set choice impacts the mean of maximum surges throughout the study area, and variability in the surge prediction due to land cover data set choice strongly depends on storm characteristics and geographical location of the bay in relation to storm track. Errors in surge estimation due to land cover choice are approximately 7% of the surge value, with change in surge prediction varying by as much as 1 m, depending on location and storm condition. Finally, the impact of land cover choice on the accuracy of simulating surges for Hurricane Bret in 1999 is evaluated.

  1. Surge capacity for healthcare systems: a conceptual framework.

    PubMed

    Kaji, Amy; Koenig, Kristi L; Bey, Tareg

    2006-11-01

    This report reflects the proceedings of a breakout session, "Surge Capacity: Defining Concepts," at the 2006 Academic Emergency Medicine Consensus Conference, "Science of Surge Capacity." Although there are several general descriptions of surge capacity in the literature, there is no universally accepted standard definition specifying the various components. Thus, the objectives of this breakout session were to better delineate the components of surge capacity and to outline the key considerations when planning for surge capacity. Participants were from diverse backgrounds and included academic and community emergency physicians, economists, hospital administrators, and experts in mathematical modeling. Three essential components of surge capacity were identified: staff, stuff, and structure. The focus on enhancing surge capacity during a catastrophic event will be to increase patient-care capacity, rather than on increasing things, such as beds and medical supplies. Although there are similarities between daily surge and disaster surge, during a disaster, the goal shifts from the day-to-day operational focus on optimizing outcomes for the individual patient to optimizing those for a population. Other key considerations in defining surge capacity include psychosocial behavioral issues, convergent volunteerism, the need for special expertise and supplies, development of a standard of care appropriate for a specific situation, and standardization of a universal metric for surge capacity.

  2. Advances in using satellite altimetry to observe storm surge

    NASA Astrophysics Data System (ADS)

    Han, Guoqi

    2017-04-01

    Storm surges are the major cause for coastal flooding, resulting in catastrophic damage to properties and loss of life in coastal communities. Thus it is important to utilize new technology to enhance our capabilities of observing storm surges and ultimately to improve our capacity for forecasting storm surges and mitigating damage and loss. In this talk we first review traditional methods of monitoring storm surges. We then provide examples of storm surges observed by nadir satellite altimetry, during Hurricane Sandy and Igor, as well as typhoon and cyclone events. We further evaluate satellite results against tide-gauge data and explain storm surge features. Finally, we discuss the potential of a wide-swath altimetry mission, the Surface Water and Ocean Topography (SWOT), for observing storm surges.

  3. Development of a new storm surge index for global prediction of tropical cyclone generated storm surge

    NASA Astrophysics Data System (ADS)

    Jordan, Mark Rickman, II

    This research involves the creation of a new storm surge index that incorporates many variables important in storm surge generation like maximum winds, radius of maximum winds, pressure, translation speed, and bathymetry. Using a two-dimensional, barotropic ocean model, power laws have been developed that describe the relationship between storm surge and changes in maximum wind, radius of maximum winds, pressure, and bathymetry. Direct curve fitting is used to describe the relationship between storm surge and changes in translation speed since a power-law relationship does not exist in that case. A database of 39 landfalling, United States hurricanes between 1986 and 2007 is used to evaluate the quality of the index. Storm parameters for all database storms are compiled using the extended best track dataset, and an index value is calculated for each storm in the database. Correlation analysis is then performed using the index values and observed maximum storm surge heights. Finally, an extensive error analysis is presented to demonstrate uncertainties in the index in both forecast and post-analysis situations.

  4. Precipitation and Moisture Sources in North American Monsoon Surges

    NASA Astrophysics Data System (ADS)

    Schiffer, N. J.; Nesbitt, S. W.

    2009-12-01

    Prediction of North American Monsoon (NAM) precipitation plays an important role in decision-making on time scales from minutes for severe weather to seasons and years for agriculture. Gulf of California (GoC) moisture surges are connected to NAM precipitation and play a role in modulating the monsoon. This study aims to improve understanding of the relationship between precipitation, surges, and the larger scale moisture sources of the NAM with the ultimate goal of improving precipitation forecasts over the monsoon region. Although previous studies have relied primarily on dew point temperature to identify surges, relative humidity accounts for the cool and moist qualities of surges simultaneously. Using an updated method to recognize surges, relative humidity, temperature, and dew point from surface observations all show distinct trends that are consistent with surges lasting 1-2 days. The NARR identifies surges more precisely based on a plan view of θe anomalies than a pseudo-surface observation at a single data point near Yuma. With an eye towards climate change, 29 years of surface observations show surge length is not changing, but surges may be growing more frequent, less humid, and warmer. Surges show a pronounced relationship with Tropical Rainfall Measuring Mission (TRMM) 3B42-estimated precipitation. As the surge progresses northward along the GoC, precipitation follows, showing little delay until the surge breaches the northern end of the GoC. Yuma, AZ, surface observations show a one-day delay between surge arrival and precipitation enhancement, probably because surge arrival is defined at the beginning of the rise in atmospheric moisture. This positive precipitation anomaly in the Desert Southwest appears at the same time that negative anomalies dominate the Great Plains, intimating an inverse relationship suggested in previous studies. In terms of surge moisture source, there is no significant connection between the GoC and an outside moisture

  5. Coastal emergency managers' preferences for storm surge forecast communication.

    PubMed

    Morrow, Betty Hearn; Lazo, Jeffrey K

    2014-01-01

    Storm surge, the most deadly hazard associated with tropical and extratropical cyclones, is the basis for most evacuation decisions by authorities. One factor believed to be associated with evacuation noncompliance is a lack of understanding of storm surge. To address this problem, federal agencies responsible for cyclone forecasts are seeking more effective ways of communicating storm surge threat. To inform this process, they are engaging various partners in the forecast and warning process.This project focuses on emergency managers. Fifty-three emergency managers (EMs) from the Gulf and lower Atlantic coasts were surveyed to elicit their experience with, sources of, and preferences for storm surge information. The emergency managers-who are well seasoned in hurricane response and generally rate the surge risk in their coastal areas above average or extremely high-listed storm surge as their major concern with respect to hurricanes. They reported a general lack of public awareness about surge. Overall they support new ways to convey the potential danger to the public, including the issuance of separate storm surge watches and warnings, and the expression of surge heights using feet above ground level. These EMs would like more maps, graphics, and visual materials for use in communicating with the public. An important concern is the timing of surge forecasts-whether they receive them early enough to be useful in their evacuation decisions.

  6. Climatic Controls on the Distribution of Surging Glaciers

    NASA Astrophysics Data System (ADS)

    Sevestre, H.; Benn, D.

    2012-12-01

    Surge-type glaciers are scattered in a non-random fashion, gathered in clusters in some glaciated regions. One group of clusters forms an Arctic and Sub-Arctic 'crescent', spanning from Alaska-Yukon, through Arctic Canada, West and East Greenland, Iceland, Svalbard and Novaya Zemlya. Another cluster occurs in western High Asia, including the Karakoram Mountains. Although several studies have assessed the influence of environmental controls on surging, so far none has provided a satisfactory explanation for the geographical location of these clusters. The distribution of such glaciers undoubtedly holds the keys of a better understanding on the controls on surging behaviour. For this study, two glacier populations are considered. First, a global inventory of glacier surges has been compiled, based on published observations, field reports and remote sensing studies. This digital database is structured in three tables, respectively providing information on the location and geometry of each surge-type glacier, surge dates and magnitude, and methodology employed at the time of observation. This global dataset is compared to the population of "non-surge-type glaciers" based on the Randolph Glacier Inventory version 2.0 excluding the inventoried surging glaciers. In both populations, glaciers are classified depending on their geometry and thermal regime. Downscaled climatic datasets are used to identify climatic envelopes associated with clusters of surging glaciers. We identified which environments are most prone to be associated to glacier surging, and examined the influence of these parameters on the surge cycle duration and character. These results emphasize the importance of external controls on surging (as against individual surges), and promote the need to study this behaviour in the frame of an energy-balance budget.

  7. Atlantic hurricane surge response to geoengineering

    PubMed Central

    Moore, John C.; Grinsted, Aslak; Guo, Xiaoran; Yu, Xiaoyong; Jevrejeva, Svetlana; Rinke, Annette; Cui, Xuefeng; Kravitz, Ben; Lenton, Andrew; Watanabe, Shingo; Ji, Duoying

    2015-01-01

    Devastating floods due to Atlantic hurricanes are relatively rare events. However, the frequency of the most intense storms is likely to increase with rises in sea surface temperatures. Geoengineering by stratospheric sulfate aerosol injection cools the tropics relative to the polar regions, including the hurricane Main Development Region in the Atlantic, suggesting that geoengineering may mitigate hurricanes. We examine this hypothesis using eight earth system model simulations of climate under the Geoengineering Model Intercomparison Project (GeoMIP) G3 and G4 schemes that use stratospheric aerosols to reduce the radiative forcing under the Representative Concentration Pathway (RCP) 4.5 scenario. Global mean temperature increases are greatly ameliorated by geoengineering, and tropical temperature increases are at most half of those temperature increases in the RCP4.5. However, sulfate injection would have to double (to nearly 10 teragrams of SO2 per year) between 2020 and 2070 to balance the RCP4.5, approximately the equivalent of a 1991 Pinatubo eruption every 2 y, with consequent implications for stratospheric ozone. We project changes in storm frequencies using a temperature-dependent generalized extreme value statistical model calibrated by historical storm surges and observed temperatures since 1923. The number of storm surge events as big as the one caused by the 2005 Katrina hurricane are reduced by about 50% compared with no geoengineering, but this reduction is only marginally statistically significant. Nevertheless, when sea level rise differences in 2070 between the RCP4.5 and geoengineering are factored into coastal flood risk, we find that expected flood levels are reduced by about 40 cm for 5-y events and about halved for 50-y surges. PMID:26504210

  8. Atlantic hurricane surge response to geoengineering

    SciTech Connect

    Moore, John C.; Grinsted, Aslak; Guo, Xiaoran; Yu, Xiaoyong; Jevrejeva, Svetlana; Rinke, Annette; Cui, Xuefeng; Kravitz, Ben; Lenton, Andrew; Watanabe, Shingo; Ji, Duoying

    2015-10-26

    Devastating Atlantic hurricanes are relatively rare events. However their intensity and frequency in a warming world may rapidly increase by a factor of 2-7 for each degree of increase in mean global temperature. Geoengineering by stratospheric sulphate aerosol injection cools the tropics relative to the polar regions, including the hurricane main development region in the Atlantic, suggesting that geoengineering may be an effective method of controlling hurricanes. We examine this hypothesis using 8 Earth System Model simulations of climate under the GeoMIP G3 and G4 schemes that use stratospheric aerosols to reduce the radiative forcing under the RCP4.5 scenario. Global mean temperature increases are greatly ameliorated by geoengineering, and tropical temperature increases are at most half of those in RCP4.5, but sulphate injection would have to double between 2020 and 2070 to balance RCP 4.5 to nearly 10 Tg SO2 yr-1, with consequent implications for damage to stratospheric ozone. We project changes in storm frequencies using a temperature-dependent Generalized Extreme Value statistical model calibrated by historical storm surges from 1923 and observed temperatures. The numbers of storm surge events as big as the one that caused the 2005 Katrina hurricane are reduced by about 50% compared with no geoengineering, but this is only marginally statistically significant. However, when sea level rise differences at 2070 between RCP4.5 and geoengineering are factored in to coastal flood risk, we find that expected flood levels are reduced by about 40 cm for 5 year events and perhaps halved for 50 year surges.

  9. Atlantic hurricane surge response to geoengineering.

    PubMed

    Moore, John C; Grinsted, Aslak; Guo, Xiaoran; Yu, Xiaoyong; Jevrejeva, Svetlana; Rinke, Annette; Cui, Xuefeng; Kravitz, Ben; Lenton, Andrew; Watanabe, Shingo; Ji, Duoying

    2015-11-10

    Devastating floods due to Atlantic hurricanes are relatively rare events. However, the frequency of the most intense storms is likely to increase with rises in sea surface temperatures. Geoengineering by stratospheric sulfate aerosol injection cools the tropics relative to the polar regions, including the hurricane Main Development Region in the Atlantic, suggesting that geoengineering may mitigate hurricanes. We examine this hypothesis using eight earth system model simulations of climate under the Geoengineering Model Intercomparison Project (GeoMIP) G3 and G4 schemes that use stratospheric aerosols to reduce the radiative forcing under the Representative Concentration Pathway (RCP) 4.5 scenario. Global mean temperature increases are greatly ameliorated by geoengineering, and tropical temperature increases are at most half of those temperature increases in the RCP4.5. However, sulfate injection would have to double (to nearly 10 teragrams of SO2 per year) between 2020 and 2070 to balance the RCP4.5, approximately the equivalent of a 1991 Pinatubo eruption every 2 y, with consequent implications for stratospheric ozone. We project changes in storm frequencies using a temperature-dependent generalized extreme value statistical model calibrated by historical storm surges and observed temperatures since 1923. The number of storm surge events as big as the one caused by the 2005 Katrina hurricane are reduced by about 50% compared with no geoengineering, but this reduction is only marginally statistically significant. Nevertheless, when sea level rise differences in 2070 between the RCP4.5 and geoengineering are factored into coastal flood risk, we find that expected flood levels are reduced by about 40 cm for 5-y events and about halved for 50-y surges.

  10. Glacier surge after ice shelf collapse.

    PubMed

    De Angelis, Hernán; Skvarca, Pedro

    2003-03-07

    The possibility that the West Antarctic Ice Sheet will collapse as a consequence of ice shelf disintegration has been debated for many years. This matter is of concern because such an event would imply a sudden increase in sea level. Evidence is presented here showing drastic dynamic perturbations on former tributary glaciers that fed sections of the Larsen Ice Shelf on the Antarctic Peninsula before its collapse in 1995. Satellite images and airborne surveys allowed unambiguous identification of active surging phases of Boydell, Sjögren, Edgeworth, Bombardier, and Drygalski glaciers. This discovery calls for a reconsideration of former hypotheses about the stabilizing role of ice shelves.

  11. Climatic and Topographic Controls on the Global Distribution of Surge-type Glaciers: Implications for a Unifying Model of Surging

    NASA Astrophysics Data System (ADS)

    Sevestre, H.; Benn, D.

    2014-12-01

    Controls on the global distribution of surge-type glaciers hold the keys to a better understanding of surge mechanisms. Our study represents the first investigation of the correlations between the global distribution of surge-type glaciers and climatic and geometric variables, using a new geodatabase inventorying all surge-type glaciers in the world. The highest densities of surge-type glaciers occur within an optimal climatic envelope bounded by temperature and precipitation. Across all regions with both surge-type and normal glaciers, the former are larger, especially at the cold, dry end of the climatic spectrum. Climate change can also alter the distribution of surge-type glaciers. A species distribution model, Maxent, accurately depicts the major clusters of surge-type glaciers using three variables: temperature, precipitation and glacier area, but under-predicts clusters found outside of the climatically optimal surge zone. We interpret the results in terms of a new enthalpy cycle model. Steady states require a balance between enthalpy gains generated by the balance flux and losses via heat conduction and meltwater discharge. This condition can be most easily satisfied in cold, dry environments (thin, low-flux glaciers, efficient conductive heat losses), and warm, humid environments (high meltwater discharges). Intermediate conditions correspond with the optimal surge zone, where neither heat conduction nor runoff can effectively discharge heat gains, and enthalpy cycling can result.

  12. Kinematics of Solar Chromospheric Surges of AR 10930

    NASA Astrophysics Data System (ADS)

    Bong, Su-Chan; Cho, Kyung-Suk; Yurchyshyn, Vasyl

    2014-12-01

    Solar chromospheric surges are often reported to contain rotational motion. However, the details of the motion and driving mechanism of the surges are not yet fully understood. Recurrent surges with rotational motion at AR 10930 on the west limb are observed by Hinode Solar Optical Telescope (SOT) continuously from 11:21 UT on December 18 to 09:58 UT on December 19, 2006, using the Ca II H broadband filter. We analyze details of the motion including number of turns from the rise of the surge to the fall, axial speed and acceleration. During the observation, rise and fall motion accompanying rotation appears recurrently. There occur a total of 14 surges at AR 10930 over 17 hours. The average duration is 45 minutes, and the average width, and length are 8 Mm, and 39 Mm, respectively. We speculate that the surges occurred by recurrent reconnections between the twisted prominence and large untwisted flux tube.

  13. The science of surge: detection and situational awareness.

    PubMed

    McManus, John; Huebner, Kermit; Scheulen, James

    2006-11-01

    As part of the broader "science of surge" consensus initiative sponsored by Academic Emergency Medicine, this report addresses the issues of detection and situational awareness as they relate to surge in the practice of emergency medicine. The purpose of this report, and the breakout group that contributed to its content, was to provide emergency physicians and other stakeholders in the emergency medicine community a sense of direction as they plan, prepare for, and respond to surge in their practice.

  14. Performance Comparison of the European Storm Surge Models and Chaotic Model in Forecasting Extreme Storm Surges

    NASA Astrophysics Data System (ADS)

    Siek, M. B.; Solomatine, D. P.

    2009-04-01

    Storm surge modeling has rapidly developed considerably over the past 30 years. A number of significant advances on operational storm surge models have been implemented and tested, consisting of: refining computational grids, calibrating the model, using a better numerical scheme (i.e. more realistic model physics for air-sea interaction), implementing data assimilation and ensemble model forecasts. This paper addresses the performance comparison between the existing European storm surge models and the recently developed methods of nonlinear dynamics and chaos theory in forecasting storm surge dynamics. The chaotic model is built using adaptive local models based on the dynamical neighbours in the reconstructed phase space of observed time series data. The comparison focused on the model accuracy in forecasting a recently extreme storm surge in the North Sea on November 9th, 2007 that hit the coastlines of several European countries. The combination of a high tide, north-westerly winds exceeding 50 mph and low pressure produced an exceptional storm tide. The tidal level was exceeded 3 meters above normal sea levels. Flood warnings were issued for the east coast of Britain and the entire Dutch coast. The Maeslant barrier's two arc-shaped steel doors in the Europe's biggest port of Rotterdam was closed for the first time since its construction in 1997 due to this storm surge. In comparison to the chaotic model performance, the forecast data from several European physically-based storm surge models were provided from: BSH Germany, DMI Denmark, DNMI Norway, KNMI Netherlands and MUMM Belgium. The performance comparison was made over testing datasets for two periods/conditions: non-stormy period (1-Sep-2007 till 14-Oct-2007) and stormy period (15-Oct-2007 till 20-Nov-2007). A scalar chaotic model with optimized parameters was developed by utilizing an hourly training dataset of observations (11-Sep-2005 till 31-Aug-2007). The comparison results indicated the chaotic

  15. Calcaneus replacement after total calcanectomy via vascularized pelvis bone.

    PubMed

    Kurvin, L A; Volkering, C; Kessler, S B

    2008-01-01

    Because of loss of function and chronic pain total calcanectomy is a serious impairment for the patient. There are few reports concerning replacement procedures using ribs [Brenner P, Zwipp H, Rammelt S. Vascularized double barrel ribs combined with free serratus anterior muscle transfer for homologous restoration of the hindfoot after calcanectomy. J Trauma-Injury Infect Crit Care 2000;49(2):331-5; Lin CH, Wei FC, Levin LS, Su JI. Free composite serratus anterior and rib flaps for tibial composite bone and soft-tissue defect. Past Reconstr Surg 1997;99:1656-65; Moscona RA, Ullmann Y, Hirshowitz B. Free composite serratus anterior muscle-rib flap for reconstruction of severely damaged foot. Ann Plast Surg 1988;20:167-72] or homologeous bone graft [Mankin HJ, Gebhardt MC, Jennings LC, Springfield DS, Tomford WW. Long-term results of allograft replacement in the management of bone tumors. Clin Orthop 1996;324:86-97; Muscolo DL, Miguel AA, Aponte-Tinao A. Long-term results of allograft replacement after total calcanectomy. J Bone Joint Surg Am 2000;82(1):109-12; Ottolenghi CE, Petracchi LJ. Chondromyxosarcoma of the calcaneus; report of a case of total replacement of involved bone with a homogenous refrigerated calcaneus. J Bone Joint Surg 1953;35A(1):211-4]. We report a case of calcaneus replacement by vascularized iliac crest bone.

  16. Simplified Storm Surge Simulations Using Bernstein Polynomials

    NASA Astrophysics Data System (ADS)

    Beisiegel, Nicole; Behrens, Jörn

    2016-04-01

    Storm surge simulations are vital for forecasting, hazard assessment and eventually improving our understanding of Earth system processes. Discontinuous Galerkin (DG) methods have recently been explored in that context, because they are locally mass-conservative and in combination with suitable robust nodal filtering techniques (slope limiters) positivity-preserving and well-balanced for the still water state at rest. These filters manipulate interpolation point values in every time step in order to retain the desirable properties of the scheme. In particular, DG methods are able to represent prognostic variables such as the fluid height at high-order accuracy inside each element (triangle). For simulations that include wetting and drying, however, the high-order accuracy will destabilize the numerical model because point values on quadrature points may become negative during the computation if they do not coincide with interpolation points. This is why the model that we are presenting utilizes Bernstein polynomials as basis functions to model the wetting and drying. This has the advantage that negative pointvalues away from interpolation points are prevented, the model is stabilized and no additional time step restriction is introduced. Numerical tests show that the model is capable of simulating simplified storm surges. Furthermore, a comparison of model results with third-order Bernstein polynomials with results using traditional nodal Lagrange polynomials reveals an improvement in numerical convergence.

  17. Hospital Bioterrorism Planning and Burn Surge

    PubMed Central

    Myers, Brent; Cairns, Charles B.; Rich, Preston B.; Hultman, C. Scott; Charles, Anthony G.; Jones, Samuel W.; Schmits, Grace L.; Skarote, Mary Beth; Holmes, James H.; Cairns, Bruce A.

    2014-01-01

    On the morning of June 9, 2009, an explosion occurred at a manufacturing plant in Garner, North Carolina. By the end of the day, 68 injured patients had been evaluated at the 3 Level I trauma centers and 3 community hospitals in the Raleigh/Durham metro area (3 people who were buried in the structural collapse died at the scene). Approximately 300 employees were present at the time of the explosion, when natural gas being vented during the repair of a hot water heater ignited. The concussion from the explosion led to structural failure in multiple locations and breached additional natural gas, electrical, and ammonia lines that ran overhead in the 1-story concrete industrial plant. Intent is the major difference between this type of accident and a terrorist using an incendiary device to terrorize a targeted population. But while this disaster lacked intent, the response, rescue, and outcomes were improved as a result of bioterrorism preparedness. This article discusses how bioterrorism hospital preparedness planning, with an all-hazards approach, became the basis for coordinated burn surge disaster preparedness. This real-world disaster challenged a variety of systems, hospitals, and healthcare providers to work efficiently and effectively to manage multiple survivors. Burn-injured patients served as a focus for this work. We describe the response, rescue, and resuscitation provided by first responders and first receivers as well as efforts made to develop burn care capabilities and surge capacity. PMID:24527874

  18. Hospital bioterrorism planning and burn surge.

    PubMed

    Kearns, Randy D; Myers, Brent; Cairns, Charles B; Rich, Preston B; Hultman, C Scott; Charles, Anthony G; Jones, Samuel W; Schmits, Grace L; Skarote, Mary Beth; Holmes, James H; Cairns, Bruce A

    2014-01-01

    On the morning of June 9, 2009, an explosion occurred at a manufacturing plant in Garner, North Carolina. By the end of the day, 68 injured patients had been evaluated at the 3 Level I trauma centers and 3 community hospitals in the Raleigh/Durham metro area (3 people who were buried in the structural collapse died at the scene). Approximately 300 employees were present at the time of the explosion, when natural gas being vented during the repair of a hot water heater ignited. The concussion from the explosion led to structural failure in multiple locations and breached additional natural gas, electrical, and ammonia lines that ran overhead in the 1-story concrete industrial plant. Intent is the major difference between this type of accident and a terrorist using an incendiary device to terrorize a targeted population. But while this disaster lacked intent, the response, rescue, and outcomes were improved as a result of bioterrorism preparedness. This article discusses how bioterrorism hospital preparedness planning, with an all-hazards approach, became the basis for coordinated burn surge disaster preparedness. This real-world disaster challenged a variety of systems, hospitals, and healthcare providers to work efficiently and effectively to manage multiple survivors. Burn-injured patients served as a focus for this work. We describe the response, rescue, and resuscitation provided by first responders and first receivers as well as efforts made to develop burn care capabilities and surge capacity.

  19. Observation of an Opposition Surge on Triton

    NASA Astrophysics Data System (ADS)

    Herbert, B. D.; Buratti, B. J.; Schmidt, B.; Bauer, J. M.; Hicks, M. D.

    2004-11-01

    Ground-based observations of Neptune's moon Triton taken during the summers of 2000, 2003, and 2004 show a rotational light curve with a large amplitude. This is in stark contrast to data from the 1989 Voyager II flyby, which implies significant changes have occurred on Triton's surface since that time. The light curve has two notable regions, one that is significantly brighter than was observed in 1989 and one that is significantly darker. Data were also taken at a broad range of solar phase angles, allowing for a comprehensive study of the effects of phase on Triton's brightness. Analysis of the phase curve yields a solar phase coefficient close to zero for phases greater than 0.08 degrees, a number in close agreement with past studies that focused on higher phase angles. We also report a previously unrecognized opposition surge. Preliminary analysis suggests that the surge has different characteristics in the dark and bright regions currently visible on Triton, implying a non-homogenous regolith. Funding for this project was provided in part by the New York Space Grant Consortium and the NASA Undergraduate Student Research Program.

  20. Method and system for turbomachinery surge detection

    DOEpatents

    Faymon, David K.; Mays, Darrell C.; Xiong, Yufei

    2004-11-23

    A method and system for surge detection within a gas turbine engine, comprises: measuring the compressor discharge pressure (CDP) of the gas turbine over a period of time; determining a time derivative (CDP.sub.D ) of the measured (CDP) correcting the CDP.sub.D for altitude, (CDP.sub.DCOR); estimating a short-term average of CDP.sub.DCOR.sup.2 ; estimating a short-term average of CDP.sub.DCOR ; and determining a short-term variance of corrected CDP rate of change (CDP.sub.roc) based upon the short-term average of CDP.sub.DCOR and the short-term average of CDP.sub.DCOR.sup.2. The method and system then compares the short-term variance of corrected CDP rate of change with a pre-determined threshold (CDP.sub.proc) and signals an output when CDP.sub.roc >CDP.sub.proc. The method and system provides a signal of a surge within the gas turbine engine when CDP.sub.roc remains>CDP.sub.proc for pre-determined period of time.

  1. Sensitivity of hurricane surge to morphological parameters of coastal wetlands

    NASA Astrophysics Data System (ADS)

    Loder, N. M.; Irish, J. L.; Cialone, M. A.; Wamsley, T. V.

    2009-10-01

    Given the history and future risk of storm surge in the United States, functional storm protection techniques are needed to protect vital sectors of the economy and coastal communities. It is widely hypothesized that coastal wetlands offer protection from storm surge and wave action, though the extent of this protection is unknown due to the complexities of flow through vegetation. Here we present the sensitivity of storm-surge numerical modeling results to various coastal wetlands characteristics. An idealized grid domain and 400-km 2 marsh feature were used to evaluate the effects of marsh characteristics on hurricane surge, including the effects of bottom friction, elevation, and continuity (the ratio of healthy marsh to open water area within the total wetland area). Through coupled hydrodynamic and wave model simulations, it is confirmed that increased bottom friction reduces storm-surge levels for most storms. However, increases in depth associated with marsh elevation loss generally results in a reduction of surge. As marsh continuity is decreased, coastal surge increases as a result of enhanced surge conveyance into and out of the marsh. Storm surge is parameterized in terms of marsh morphology, namely marsh elevation, frictional characteristics, and degree of segmentation, which will assist in the justification for and optimization of marsh restoration in terms of storm protection.

  2. Physically based assessment of hurricane surge threat under climate change

    NASA Astrophysics Data System (ADS)

    Lin, Ning; Emanuel, Kerry; Oppenheimer, Michael; Vanmarcke, Erik

    2012-06-01

    Storm surges are responsible for much of the damage and loss of life associated with landfalling hurricanes. Understanding how global warming will affect hurricane surges thus holds great interest. As general circulation models (GCMs) cannot simulate hurricane surges directly, we couple a GCM-driven hurricane model with hydrodynamic models to simulate large numbers of synthetic surge events under projected climates and assess surge threat, as an example, for New York City (NYC). Struck by many intense hurricanes in recorded history and prehistory, NYC is highly vulnerable to storm surges. We show that the change of storm climatology will probably increase the surge risk for NYC; results based on two GCMs show the distribution of surge levels shifting to higher values by a magnitude comparable to the projected sea-level rise (SLR). The combined effects of storm climatology change and a 1m SLR may cause the present NYC 100-yr surge flooding to occur every 3-20yr and the present 500-yr flooding to occur every 25-240yr by the end of the century.

  3. The role of mangroves in attenuating storm surges

    NASA Astrophysics Data System (ADS)

    Zhang, Keqi; Liu, Huiqing; Li, Yuepeng; Xu, Hongzhou; Shen, Jian; Rhome, Jamie; Smith, Thomas J.

    2012-05-01

    Field observations and numerical simulations indicate that the 6-to-30-km-wide mangrove forest along the Gulf Coast of South Florida effectively attenuated storm surges from a Category 3 hurricane, Wilma, and protected the inland wetland by reducing an inundation area of 1800 km2 and restricting surge inundation inside the mangrove zone. The surge amplitude decreases at a rate of 40-50 cm/km across the mangrove forest and at a rate of 20 cm/km across the areas with a mixture of mangrove islands with open water. In contrast, the amplitudes of storm surges at the front of the mangrove zone increase by about 10-30% because of the "blockage" of mangroves to surge water, which can cause greater impacts on structures at the front of mangroves than the case without mangroves. The mangrove forest can also protect the wetlands behind the mangrove zone against surge inundation from a Category 5 hurricane with a fast forward speed of 11.2 m/s (25 mph). However, the forest cannot fully attenuate storm surges from a Category 5 hurricane with a slow forward speed of 2.2 m/s (5 mph) and reduced surges can still affect the wetlands behind the mangrove zone. The effects of widths of mangrove zones on reducing surge amplitudes are nonlinear with large reduction rates (15-30%) for initial width increments and small rates (<5%) for subsequent width increments.

  4. On the surging potential of polar ice streams: Part 1, Sliding and surging of large ice masses: A review

    SciTech Connect

    McInnes, B.; Radok, U.; Budd, W.F.; Smith, I.N.

    1985-01-01

    The main features of glacier surges were well known by the time the first detailed glacier dynamics and ice flow law came into being during the 1950s. The surging potential of polar ice streams raises additional questions which remain to be answered by a combination of observations and model refinements. This report reviews the available evidence on glacier sliding, and the main concepts and hypotheses that have been advanced for the surging phenomenon.

  5. Outcome of Dupuytren Contractures After Collagenase Clostridium Histolyticum Injection: A Single-institution Experience.

    PubMed

    Hwee, Yin Kan; Park, Daniel; Vinas, Marisa; Litts, Christopher; Friedman, David

    2017-08-01

    Collagenase clostridium histolyticum (CCH) injection is an alternative to surgery for patients with Dupuytren disease (DD) of the metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joints. The success of surgical and nonsurgical treatment modalities for DD is reported to vary widely between 25% and 80% (J Bone Joint Surg Am. 1985;67:1439-1443; Plast Reconstr Surg. 2007;120:44e-54e; J Bone Joint Surg Am. 2007;89:189-198; J Hand Surg Am. 2011:36:936-942; J Hand Surg Am. 1990;15:755-761; J Hand Surg Br. 1996;21:797-800; J Bone Joint Surg Br. 2000;82:90-94; Plast Reconstr Surg. 2005;115:802-810; Ann Plast Surg. 2006;57:13-17). This study presents the outcomes of patients with DD contractures treated with CCH injections at a single institution. An institutional review board-approved retrospective study was conducted of patients with DD of the hand treated with CCH injections in a single institution from February 2010 to April 2015. All patients received the recommended dose of 0.58 mg of CCH and returned for joint manipulation the following day. Data for follow-up at 7 and 30 days postoperatively and up to 5 years for patients who returned seeking further therapy for recurrent symptoms were reviewed. One hundred thirteen patients with a total of 146 affected joints (72 MCP; 74 PIP) were treated with CCH injections (95 males; 18 females; age, 40-92 y). Successful CCH therapy occurred in 75% of injected joints (109/146 joints; 59 MCP; 50 PIP), as defined by less than 5 degrees of contracture after treatment. Twenty-three percent of treated joints had partial correction (34/146 joints; 13 MCP; 21 PIP), as defined by between 5 and 30 degrees of residual contracture after treatment. Three patients (2%) had a failure of treatment, as defined by unchanged or worsened contracture from pretreatment baseline measurements. Fifteen patients (13%) returned to the clinic seeking additional therapy for recurrent joint contracture symptoms in 17 joints over a span of 1

  6. Storm surges formation in the White and Barents Seas

    NASA Astrophysics Data System (ADS)

    Arkhipkin, Victor; Dobrolyubov, Sergey; Korablina, Anastasia; Myslenkov, Stanislav

    2016-04-01

    Investigation of storm surges in the Arctic seas are of high priority in Russia due to the active development of offshore oil and gas, construction of facilities in the coastal zone, as well as for the safety of navigation. It is important to study the variability of surges, to predict this phenomena and subsequent economic losses, thus including such information into the Russian Arctic Development Program 2020. Surges in the White and Barents Seas are caused mainly by deep cyclones of two types: "diving" from the north (88% of all cyclones) and western. The average height of the storm surges in the White Sea is 0.6-0.9 m. An average duration of storm surges is about 80 hours. Mathematical modeling is used to analyze the characteristics of storm surges formation in the Dvina Bay of the White Sea, and in the Varandey village on the Barents Sea coast. Calculating storm surge heights in the White and Barents seas is performed using the ADCIRC model on an unstructured grid with a step from 20 km in the Barents Sea to 100 m in the White Sea. Unstructured grids allowed keeping small features of the coastline of the White and Barents seas, small islands and shallow banks, and assessing their impact on the development and transformation of wind-generated waves. The ADCIRC model used data of wind field reanalysis CFSv2. The storm surges were simulated for the time period from 1979 to 2010 and included scenarios with / without direct atmospheric pressure forcing, waves and tides. Numerical experiments have revealed distribution of storm surges in channels of the Northern Dvina River delta. The storm surges spreads in the model from the north-north-west of the Dvina Bay. As storm surge moves from the wellhead to the seaside estuary of the Northern Dvina (district Solombala), its height increases from 0.5 to 2 m. We also found a non-linear interaction of the surge and tide during the phase of surge destruction. This phenomenon is the highest in the period of low water, and the

  7. Storm surge along the Pacific coast of North America

    NASA Astrophysics Data System (ADS)

    Bromirski, Peter D.; Flick, Reinhard E.; Miller, Arthur J.

    2017-01-01

    Storm surge is an important factor that contributes to coastal flooding and erosion. Storm surge magnitude along eastern North Pacific coasts results primarily from low sea level pressure (SLP). Thus, coastal regions where high surge occurs identify the dominant locations where intense storms make landfall, controlled by storm track across the North Pacific. Here storm surge variability along the Pacific coast of North America is characterized by positive nontide residuals at a network of tide gauge stations from southern California to Alaska. The magnitudes of mean and extreme storm surge generally increase from south to north, with typically high amplitude surge north of Cape Mendocino and lower surge to the south. Correlation of mode 1 nontide principal component (PC1) during winter months (December-February) with anomalous SLP over the northeast Pacific indicates that the dominant storm landfall region is along the Cascadia/British Columbia coast. Although empirical orthogonal function spatial patterns show substantial interannual variability, similar correlation patterns of nontide PC1 over the 1948-1975 and 1983-2014 epochs with anomalous SLP suggest that, when considering decadal-scale time periods, storm surge and associated tracks have generally not changed appreciably since 1948. Nontide PC1 is well correlated with PC1 of both anomalous SLP and modeled wave height near the tide gauge stations, reflecting the interrelationship between storms, surge, and waves. Weaker surge south of Cape Mendocino during the 2015-2016 El Niño compared with 1982-1983 may result from changes in Hadley circulation. Importantly from a coastal impacts perspective, extreme storm surge events are often accompanied by high waves.

  8. Surges Initiated by Newly-emerging Satellite Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Wang, Jun-feng; Zhou, Tuan-hui; Ji, Hai-sheng

    2014-01-01

    On July 22, 2011 and in the active region NOAA 11259 there ap- peared the event of the ejection of solar atmospheric Hα surges. According to the full-disc Hα observations of the Big Bear Solar Observatory in United States, three consecutive surges at one and the same place in the north of the main spot of the active region were discovered. The trajectories of these three surges exhib- ited the figure of straight lines, and their integral configuration is like an inverted Eiffel Tower. The first two surges are quite similar, and in each of them there appeared two bright points in the northern part of the main spot. After several minutes, the surges appeared in the midst of bright points. When the bright- ness of the bright points attained the maximum value, the surges spouted out from the midst of bright points. And after reaching the maximum altitude, they quickly vanished. Before the ejection of the third surge took place, no bright points appeared. Besides, its maximal altitude is merely one half of that of the first two surges. Via a comparison with the SDO/HMI (Solar Dynamics Obser- vatory/Helioseismic and Magnetic Imager) data of radial magnetic fields, it is found that in more than one hour before the appearance of the first surge there emerged bipolar magnetic fields in the region of ejection. Besides, in several min- utes before the ejection of each Hα surge the magnetic fluxes of positive polarity diminished. Via our analysis it is found that there appeared reconnections be- tween the newly emerging satellite magnetic fields and the preexisting magnetic fields in the spot, and this caused the continuous ejections of Hα surges.

  9. Scenario-based Storm Surge Vulnerability Assessment of Catanduanes

    NASA Astrophysics Data System (ADS)

    Suarez, J. K. B.

    2015-12-01

    After the devastating storm surge effect of Typhoon Haiyan, the public recognized an improved communication about risks, vulnerabilities and what is threatened by storm surge. This can be provided by vulnerability maps which allow better visual presentations and understanding of the risks and vulnerabilities. Local implementers can direct the resources needed for protection of these areas. Moreover, vulnerability and hazard maps are relevant in all phases of disaster management designed by the National Disaster Risk Reduction Council (NDRRMC) - disaster preparedness, prevention and mitigation and response and recovery and rehabilitation. This paper aims to analyze the vulnerability of Catanduanes, a coastal province in the Philippines, to storm surges in terms of four parameters: population, built environment, natural environment and agricultural production. The vulnerability study relies on the storm surge inundation maps based on the Department of Science and Technology Nationwide Operational Assessment of Hazards' (DOST-Project NOAH) proposed four Storm Surge Advisory (SSA) scenarios (1-2, 3, 4, and 5 meters) for predicting storm surge heights. To determine total percent affected for each parameter elements, an overlay analysis was performed in ArcGIS Desktop. Moreover, vulnerability and hazard maps are generated as a final output and a tool for visualizing the impacts of storm surge event at different surge heights. The result of this study would help the selected province to know their present condition and adapt strategies to strengthen areas where they are found to be most vulnerable in order to prepare better for the future.

  10. Risk assessment of hurricane storm surge for New York City

    NASA Astrophysics Data System (ADS)

    Lin, N.; Emanuel, K. A.; Smith, J. A.; Vanmarcke, E.

    2010-09-01

    Hurricane storm surge presents a major hazard for the United States. We apply a model-based risk assessment methodology to investigate hurricane storm surge risk for New York City (NYC). We couple a statistical/deterministic hurricane model with the hydrodynamic model SLOSH (sea, lake, and overland surges from hurricanes) to generate a large number of synthetic surge events; the SLOSH model simulations are compared to advanced circulation model simulations. Statistical analysis is carried out on the empirical data. It is observed that the probability distribution of hurricane surge heights at the Battery, NYC, exhibited a heavy tail, which essentially determines the risk of New York City being struck by a catastrophic coastal flood event. The peaks-over-threshold method with the generalized Pareto distribution is applied to estimate the upper tail of the surge heights. The resulting return periods of surge heights are consistent with those of other studies for the New York area. This storm surge risk assessment methodology may be applied to other coastal areas and can be extended to consider the effect of future climate change.

  11. 14 CFR 33.65 - Surge and stall characteristics.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Surge and stall characteristics. 33.65 Section 33.65 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.65 Surge...

  12. 14 CFR 33.65 - Surge and stall characteristics.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Surge and stall characteristics. 33.65 Section 33.65 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.65 Surge...

  13. Storm-surge measurements and computations for Hurricane David

    SciTech Connect

    Howell, G.; Lee, D.Y.; Wang, H.

    1982-08-01

    One of the objectives of the Coastal Data Network System established and maintained by the Coastal and Oceanographic Engineering Laboratory at the University of Florida is to acquire and document storm surge data along the Florida Coast. Since the establishment of the system only one major hurricane resulted in storm surge of significance. This was Hurricane David which swept through the lower part of Florida's east coast in September 1979. Storm surge data were obtained at Miami Beach, Palm Beach, and Vero Beach. These data were analyzed and documented. In addition, the numerical storm surge model developed by Dean and Chiu was used to compute the storm surges at Palm Beach and Vero Beach to facilitate comparisons.

  14. Development of a state medical surge plan, Part II: Components of a medical surge plan.

    PubMed

    Moser, Royce; Connelly, Colleen; Baker, Lloyd; Barton, Richard; Buttrey, Jan; Morris, Stephen; Saffle, Jeffrey; Whitney, Jolene R

    2006-01-01

    In 2003, the Utah State Department of Health received funding from the Health Resources and Services Administration to develop a medical surge plan to increase the number of available hospital beds in the state by 1250 beds, including 125 beds for burn or critical trauma patients. A prior article discussed the planning procedures and process. This article describes the major components of the plan, including analysis of threats, direction and control, activation and system response; communications; and critical issues.

  15. Surge dynamics and lake outbursts of Kyagar Glacier, Karakoram

    NASA Astrophysics Data System (ADS)

    Round, Vanessa; Leinss, Silvan; Huss, Matthias; Haemmig, Christoph; Hajnsek, Irena

    2017-03-01

    The recent surge cycle of Kyagar Glacier, in the Chinese Karakoram, caused formation of an ice-dammed lake and subsequent glacial lake outburst floods (GLOFs) exceeding 40 million m3 in 2015 and 2016. GLOFs from Kyagar Glacier reached double this size in 2002 and earlier, but the role of glacier surging in GLOF formation was previously unrecognised. We present an integrative analysis of the glacier surge dynamics from 2011 to 2016, assessing surge mechanisms and evaluating the surge cycle impact on GLOFs. Over 80 glacier surface velocity fields were created from TanDEM-X (TerraSAR-X add-on for Digital Elevation Measurement), Sentinel-1A, and Landsat satellite data. Changes in ice thickness distribution were revealed by a time series of TanDEM-X elevation models. The analysis shows that, during a quiescence phase lasting at least 14 years, ice mass built up in a reservoir area at the top of the glacier tongue, and the terminus thinned by up to 100 m, but in the 2 years preceding the surge onset this pattern reversed. The surge initiated with the onset of the 2014 melt season, and in the following 15 months velocity evolved in a manner consistent with a hydrologically controlled surge mechanism. Dramatic accelerations coincided with melt seasons, winter deceleration was accompanied by subglacial drainage, and rapid surge termination occurred following the 2015 GLOF. Rapid basal motion during the surge is seemingly controlled by high water pressure, caused by input of surface water into either an inefficient subglacial drainage system or unstable subglacial till. The potential lake volume increased to more than 70 million m3 by late 2016, as a result of over 60 m of thickening at the terminus. Lake formation and the evolution of the ice dam height should be carefully monitored through remote sensing to anticipate large GLOFs in the near future.

  16. Application of short-data methods on extreme surge levels

    NASA Astrophysics Data System (ADS)

    Feng, X.

    2014-12-01

    Tropical cyclone-induced storm surges are among the most destructive natural hazards that impact the United States. Unfortunately for academic research, the available time series for extreme surge analysis are very short. The limited data introduces uncertainty and affects the accuracy of statistical analyses of extreme surge levels. This study deals with techniques applicable to data sets less than 20 years, including simulation modelling and methods based on the parameters of the parent distribution. The verified water levels from water gauges spread along the Southwest and Southeast Florida Coast, as well as the Florida Keys, are used in this study. Methods to calculate extreme storm surges are described and reviewed, including 'classical' methods based on the generalized extreme value (GEV) distribution and the generalized Pareto distribution (GPD), and approaches designed specifically to deal with short data sets. Incorporating global-warming influence, the statistical analysis reveals enhanced extreme surge magnitudes and frequencies during warm years, while reduced levels of extreme surge activity are observed in the same study domain during cold years. Furthermore, a non-stationary GEV distribution is applied to predict the extreme surge levels with warming sea surface temperatures. The non-stationary GEV distribution indicates that with 1 Celsius degree warming in sea surface temperature from the baseline climate, the 100-year return surge level in Southwest and Southeast Florida will increase by up to 40 centimeters. The considered statistical approaches for extreme surge estimation based on short data sets will be valuable to coastal stakeholders, including urban planners, emergency managers, and the hurricane and storm surge forecasting and warning system.

  17. Risk Assessment of Hurricane Storm Surge for Tampa Bay

    NASA Astrophysics Data System (ADS)

    Lin, N.; Emanuel, K.

    2011-12-01

    Hurricane storm surge presents a major hazard for the United States and many other coastal areas around the world. Risk assessment of current and future hurricane storm surge provides the basis for risk mitigation and related decision making. This study investigates the hurricane surge risk for Tampa Bay, located on the central west coast of Florida. Although fewer storms have made landfall in the central west Florida than in regions farther west in the Gulf of Mexico and the east coast of U.S., Tampa Bay is highly vulnerable to storm surge due to its geophysical features. It is surrounded by low-lying lands, much of which may be inundated by a storm tide of 6 m. Also, edge waves trapped on the west Florida shelf can propagate along the coastline and affect the sea level outside the area of a forced storm surge; Tampa Bay may be affected by storms traversing some distance outside the Bay. Moreover, when the propagation speed of the edge wave is close to that of a storm moving parallel to the coast, resonance may occur and the water elevation in the Bay may be greatly enhanced. Therefore, Tampa Bay is vulnerable to storms with a broad spectrum of characteristics. We apply a model-based risk assessment method to carry out the investigation. To estimate the current surge risk, we apply a statistical/deterministic hurricane model to generate a set of 1500 storms for the Tampa area, under the observed current climate (represented by 1981-2000 statistics) estimated from the NCAR/NCEP reanalysis. To study the effect of climate change, we use four climate models, CNRM-CM3, ECHAM, GFDL-CM2.0, and MIROC3.2, respectively, to drive the hurricane model to generate four sets of 1500 Tampa storms under current climate conditions (represented by 1981-2000 statistics) and another four under future climate conditions of the IPCC-AR4 A1B emission scenario (represented by 2081-2100 statistics). Then, we apply two hydrodynamic models, the Advanced Circulation (ADCIRC) model and the Sea

  18. Reassessing Storm Surge Risk for New York City (Invited)

    NASA Astrophysics Data System (ADS)

    Lin, N.; Emanuel, K.

    2013-12-01

    New York City (NYC) is highly vulnerable to tropical cyclone (TC) storm surge flooding. In a previous study, we coupled a (reanalysis- or GCM-driven) hurricane model with hydrodynamic models to simulate large numbers of synthetic surge events under observed and projected climates and assess surge threat for NYC. The storm surge return levels under the current and future climates (IPCC AR4 A1B scenario) were obtained. The results showed that the distribution of surge levels may shift to higher values in the future by a magnitude comparable to the projected sea-level rise. The study focused on typical TCs that have a storm size of the climatological mean for the Atlantic Basin and pass within a 200-km radius of the Battery, NYC. In October 2012, Hurricane Sandy, a barely Category-1 storm that made landfall about 200-km southwest from the Battery, caused the highest surge flooding of the instrumental record (~3.5 m above the mean sea level or ~2.8 m surge over the high tide) at the Battery. The extreme surge was due to the fact that the storm was a 'hybrid' event, undergoing extensive extratropical transition when making landfall almost perpendicularly to the NJ coast with an unusually large size. Sandy's case calls for a reassessment of storm surge risk for NYC that account for the special features of the storms in this region. In this reassessment, we account for the effect of extratropical transition on the wind fields through improving the surface background wind estimation, which was assumed to be uniform for typical TCs, by developing a representation of the interaction between the highly localized potential vorticity anomaly of the TC and its environmental baroclinic fields. We account for the storm size variation through incorporating the full probability distribution of the size for the region. Our preliminary results show that estimated wind and surge return levels are much higher with the effect of extratropical transition. The effect of the storm size

  19. Storm Surge and Tide Interaction: A Complete Paradigm

    NASA Astrophysics Data System (ADS)

    Horsburgh, K.

    2014-12-01

    Estimates show that in 2005, in the largest 136 coastal cities, there were 40 million people and 3,000 billion of assets exposed to 1 in 100 year coastal flood events. Mean sea level rise will increase this exposure to 150 million people and 35,000 billion of assets by 2070. Any further change in the statistics of flood frequency or severity would impact severely on economic and social systems. It is therefore crucial to understand the physical drivers of extreme storm surges, and to have confidence in datasets used for extreme sea level statistics. Much previous research has focussed on the process of tide-surge interaction, and it is now widely accepted that the physical basis of tide-surge interaction is that a phase shift of the tidal signal represents the effect of the surge on the tide. The second aspect of interaction is that shallow water momentum considerations imply that differing tidal states should modulate surge generation: wind stress should have greater surge-generating potential on lower tides. We present results from a storm surge model of the European shelf that demonstrate that tidal range does have an effect on the surges generated. The cycle-integrated effects of wind stress (i.e. the skew surge) are greater when tidal range is low. Our results contradict the absence of any such correlation in tide gauge records. This suggests that whilst the modulating effect of the tide on the skew surge (the time-independent difference between peak prediction and observations) is significant, the difference between individual storms is dominant. This implies that forecasting systems must predict salient detail of the most intense storms. A further implication is that flood forecasting models need to simulate tides with acceptable accuracy at all coastal locations. We extend our model analysis to show that the same modulation of storm surges (by tidal conditions) applies to tropical cyclones. We conduct simulations using a mature operational storm surge model

  20. Evolution of surge levels inside of the Seine Bay : interactions between tide and surge levels during Johanna and Xynthia storms

    NASA Astrophysics Data System (ADS)

    Laborie, Vanessya; Sergent, Philippe

    2015-04-01

    Within the Technical Commission for the Study and the Evaluation of Maritime Submersions in the Seine Estuary (CTeeSMES), which aim is to improve the collective knowledge on physical processes related to maritime surge levels, a numerical model of the Atlantic French Coast based on TELEMAC2D was used to study the evolution of surge levels from the ocean to the harbour area of Le Havre and evaluate the interactions between tide and surge levels in the Seine Bay. The numerical model was specifically calibrated on JOHANNA and XYNTHIA storm events, which respectively occurred in March 2008 and in February 2010. To calibrate the global signal (tide + surge levels), measurements available on 18 outputs of the Atlantic coast were used to optimize the coefficient for wind influence and for bottom friction. Maritime boundary conditions were provided by the North East Atlantic Atlas (LEGOS). Winds and pressure fields were CFSR data. Once the numerical model had been calibrated both for tide and surge levels, it has been possible to draw the evolution of surge levels from the ocean to Le Havre (quai Meunier) and then to compare the signal obtained at each point of the Seine Bay with that obtained without taking into consideration tide for each event. That also allowed to evaluate the contribution of interactions between tide and surge levels inside of the Seine Bay for Xynthia and Johanna events, but also for other events in the slice [1979-2010] and considering climate change towards 2100 with IPCC5 scenarios. It appears that instantaneous interactions between tide and surge levels nearly reach 50 % of the global surge levels and can sharply influence the evolution of surge levels in the Seine Bay depending of the moment (high tide or low water) at which the storm occurs.

  1. Storm Surge Simulation and Ensemble Forecast for Hurricane Irene (2011)

    NASA Astrophysics Data System (ADS)

    Lin, N.; Emanuel, K.

    2012-12-01

    Hurricane Irene, raking the U.S. East Coast during the period of 26-30 August 2011, caused widespread damage estimated at $15.8 billion and was responsible for 49 direct deaths (Avila and Cangialosi, 2011). Although the most severe impact in the northeastern U.S. was catastrophic inland flooding, with its unusually large size, Irene also generated high waves and storm surges and caused moderate to major coastal flooding. The most severe surge damage occurred between Oregon Inlet and Cape Hatteras in North Carolina (NC). Significant storm surge damage also occurred along southern Chesapeake Bay, and moderate and high surges were observed along the coast from New Jersey (NJ) northward. A storm surge of 0.9-1.8 m caused hundreds of millions of dollars in property damage in New York City (NYC) and Long Island, despite the fact that the storm made landfall to the west of NYC with peak winds of no more than tropical storm strength. Making three U.S. landfalls (in NC, NJ, and NY), Hurricane Irene provides a unique case for studying storm surge along the eastern U.S. coastline. We apply the hydrodynamic model ADCIRC (Luettich et al. 1992) to conduct surge simulations for Pamlico Sound, Chesapeake Bay, and NYC, using best track data and parametric wind and pressure models. The results agree well with tidal-gauge observations. Then we explore a new methodology for storm surge ensemble forecasting and apply it to Irene. This method applies a statistical/deterministic hurricane model (Emanuel et al. 2006) to generate large numbers of storm ensembles under the storm environment described by the 51 ECMWF ensemble members. The associated surge ensembles are then generated with the ADCIRC model. The numerical simulation is computationally efficient, making the method applicable to real-time storm surge ensemble forecasting. We report the results for NYC in this presentation. The ADCIRC simulation using the best track data generates a storm surge of 1.3 m and a storm tide of 2.1 m

  2. Surge instability on a cavitating propeller

    NASA Astrophysics Data System (ADS)

    Duttweiler, Mark Edward

    2001-11-01

    The present study details results from experiments investigating a surge instability on a cavitating propeller. Initially, the stable behavior of the propeller is explored, and the nature and extent of the cavitation is documented at various experimental conditions, including propeller yaw. The cavitation surge instability is first explored through visual observation of the cavitation on the propeller blades and in the tip vortices. Particular note is made of similarities between the behavior of the re-entrant jets and that noted by other investigators. It is also observed that the nature of the instability is closely related to the partial cavity instability observed on single, two-dimensional hydrofoils. The flow conditions that lead to instability are determined and it is shown that onset corresponds to a specific configuration of attached cavity lengths on an individual propeller blade. Pressure measurements are obtained from transducers within the experimental facility, and the acoustic signature of the instability is identified. The magnitude of the fluctuating pressures is very large, presumably capable of producing severe hull vibration. A simple model is developed based on cavity volume estimates obtained from high speed video footage, and the predictions of the model are compared with the experimentally obtained pressures. To assess the significance of the surrounding facility in initiating and sustaining the instability, a model is developed for the experimental facility dynamics. The predictions of this model are then compared with an experimentally determined facility response to a volumetric excitation imposed by an oscillating piston. To quantify the response of the cavitation to fluctuations in test section conditions, quasistatic estimates are obtained for the cavitation compliance and mass flow gain factor of the propeller. These parameters have previously been employed in developing system transfer functions for cavitating pumps. Finally, a model

  3. Opposition Surge: Sunlight Glinting off Mars

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Mars Global Surveyor was presented with a unique opportunity February 13-18, 1998, to image sunlight glinting off of the surface and atmospheric haze of Mars. Orbits 130-137 were devoted to obtaining MOC images of this effect, also known as opposition surge. During each orbit in mid-February, the Mars Global Surveyor spacecraft passed close to and through the line between the Sun and the center of Mars. In other words, the phase angle (angle between the Sun's incident light and the direction from the surface to the spacecraft) was near zero degrees. The sunlight reflecting from Mars near the zero phase angle produces the rare sun-glint phenomenon. The size and brightness of the glint depends on the physical properties of the surface (dust, sand, and rock distribution) and the atmosphere (haze/suspended dust). Studies of these images are expected to yield important information that can be compared with thermal emission observations.

    The picture is a color composite of MOC images 13601 (red wide angle) and 13602 (blue wide angle). The green-color band is synthesized from the red and blue using a relationship well-understood from Viking images of the late 1970s. The large, dark region near the top-center of the picture is Sinus Meridiani. The circular feature at the upper right is the impact basin, Schiaparelli. The opposition surge feature --the sun glint-- is centered around 21.0oS latitude, 4.1oW longitude.

    The two images were taken on Mars Global Surveyor's 136th orbit on February 18, 1998. Orbit 136 was the second-to-last orbit on which MOC obtained images of Mars during the first aerobraking phase (AB-1) of the mission. MOC was off between the end of AB-1 on February 19, 1998, until the start of Science Phasing Orbit-1 phase (SPO-1), which began March 28 and ended April 28, 1998.

    Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its

  4. Applications for mid-range forecasts - Simulations of storm surges

    NASA Astrophysics Data System (ADS)

    Jurado, Oscar; Rögnvaldsson, Ólafur; Ruiz-Angulo, Angel

    2017-04-01

    A possible application for mid- to long range forecasts is the simulation of storm surges. Storm surge is the abnormal rise of water generated by a storm, over and above the predicted astronomical tide. The main forcing for a storm surge is due to the wind stress from big storms, usually tropical cyclones. The goal of this project was to model storm surges at the Atlantic- and Indian Ocean coasts of Africa, using predicted winds and surface pressure from a mid-range weather forecast model. For the storm surge simulation the ADvanced CIRCulation (ADCIRC) numerical model was used. The ADCIRC model has an unstructured mesh, developed specifically for this project, with a resolution of approximately 4 km along the coast of Africa. The weather forecast is created by the Advanced Research WRF model, run at a 9 km horizontal resolution for a region covering the continental Africa. We were able to successfully use the meteorological forecast data to initialise and force the storm surge forecast. The results show that while the storm surge model is able to see changes in ocean free surface level, it has some issues with forecasting the correct amplitude change for specific locations. This could be solved by increasing the resolution along the coast, but it should be noted that bathymetry data is a big limitation for doing so in the region.

  5. Observing storm surges from space: Hurricane Igor off Newfoundland

    PubMed Central

    Han, Guoqi; Ma, Zhimin; Chen, Dake; deYoung, Brad; Chen, Nancy

    2012-01-01

    Coastal communities are becoming increasingly more vulnerable to storm surges under a changing climate. Tide gauges can be used to monitor alongshore variations of a storm surge, but not cross-shelf features. In this study we combine Jason-2 satellite measurements with tide-gauge data to study the storm surge caused by Hurricane Igor off Newfoundland. Satellite observations reveal a storm surge of 1 m in the early morning of September 22, 2010 (UTC) after the passage of the storm, consistent with the tide-gauge measurements. The post-storm sea level variations at St. John's and Argentia are associated with free equatorward-propagating continental shelf waves (with a phase speed of ~10 m/s and a cross-shelf decaying scale of ~100 km). The study clearly shows the utility of satellite altimetry in observing and understanding storm surges, complementing tide-gauge observations for the analysis of storm surge characteristics and for the validation and improvement of storm surge models. PMID:23259048

  6. Spatial Variation in Storm Surge in the Strait of Georgia

    NASA Astrophysics Data System (ADS)

    Soontiens, N. K.; Allen, S. E.; Latornell, D.; Le Souef, K.; Machuca, I.

    2014-12-01

    The Strait of Georgia is a strongly stratified, deep body of water located between Vancouver Island and the mainland of British Columbia and is connected to the Pacific Ocean via the Strait of Juan de Fuca to the south and Johnstone Strait to the north. It is on average 220 km in length and 30 km wide and its maximum depth is 420 m. During the winter months, coastal communities in the Strait of Georgia are at risk to flooding caused by storm surges, a natural hazard that occurs when a strong wind storm with low atmospheric pressure coincides with an unusually high tide. This study presents storm surge hindcasts of significant events between 2006 and 2009 using a numerical model of the Straits of Georgia, Juan de Fuca, Johnstone and Puget Sound (together the Salish Sea). The model is based on the Nucleus for European Modelling of the Ocean (NEMO) in a regional configuration. Realistic stratification is produced by including input from the surrounding rivers. A discussion on the sensitivity of modelled surge amplitude to open boundary conditions and atmospheric forcing will be presented. As barotropic models have previously shown, the surge entering the domain from the Pacific Ocean contributes most significantly. Surge amplitudes are found to be greater within the Strait of Georgia than those in the Strait of Juan de Fuca. Local wind patterns cause spatial variations in the strength of the surge in the Strait of Georgia, generally leading to stronger surges on the Mainland side of the Strait.

  7. Semidiurnal perturbations to the surge of Hurricane Irene

    NASA Astrophysics Data System (ADS)

    Branyon, J. M.; Olabarrieta, M.; Valle-Levinson, A.

    2013-05-01

    Hurricane Irene caused storm surges along the entire eastern United States coast, from Florida to Maine, in August 2011. The surge reached maximum levels of >1.5 m around New York City. Irene's surges were dominated by onshore winds and were followed by water-level set-down because of offshore winds. However, detided (observed minus predicted) water levels displayed semidiurnal (M2) oscillations off northern Florida and southern Georgia as the hurricane was impacting the South Atlantic Bight. The oscillations attained maximum amplitude (~0.4 m) when the hurricane's eye approached the coastline in South Carolina on August 27th. The M2 frequency of the oscillations implied tide surge interactions caused by a phase lag in the quasi-standing tides of the region. These unanticipated oscillations resembled Kelvin waves as they propagated southward and were greater than the initial surge observed in northern Florida and southern Georgia. It is proposed that these 'semidiurnal surges' were caused by surface, bottom and Reynolds stresses and need to be accounted for in future forecasts of storm surges.

  8. Observing storm surges from space: Hurricane Igor off Newfoundland.

    PubMed

    Han, Guoqi; Ma, Zhimin; Chen, Dake; Deyoung, Brad; Chen, Nancy

    2012-01-01

    Coastal communities are becoming increasingly more vulnerable to storm surges under a changing climate. Tide gauges can be used to monitor alongshore variations of a storm surge, but not cross-shelf features. In this study we combine Jason-2 satellite measurements with tide-gauge data to study the storm surge caused by Hurricane Igor off Newfoundland. Satellite observations reveal a storm surge of 1 m in the early morning of September 22, 2010 (UTC) after the passage of the storm, consistent with the tide-gauge measurements. The post-storm sea level variations at St. John's and Argentia are associated with free equatorward-propagating continental shelf waves (with a phase speed of ~10 m/s and a cross-shelf decaying scale of ~100 km). The study clearly shows the utility of satellite altimetry in observing and understanding storm surges, complementing tide-gauge observations for the analysis of storm surge characteristics and for the validation and improvement of storm surge models.

  9. Assessment of Storm Surge Forecasting Methods Used During Typhoon Haiyan

    NASA Astrophysics Data System (ADS)

    Mahar Francisco Lagmay, Alfredo; Malano, Vicente

    2014-05-01

    On 8 November 2013, Super Typhoon Haiyan made landfall in the central part of the Philippines. Considered one of the most powerful typhoons ever to make landfall in recorded history with 315 kph one-minute maximum sustained winds according to the Joint Typhoon Warning Center (JTWC), Haiyan brought widespread devastation in its path. Strong winds, heavy rainfall, and storm surges caused massive loss of lives and extensive damage to property. Storm surges were primarily responsible for the 6,201 dead, 1,785 missing and 28,626 injured in Haiyan's aftermath. This study documents the Haiyan storm surge simulations which were used as basis for the warnings provided to the public. The storm tide -- storm surge added to astronomical tide levels -- forecasts were made using the Japan Meteorological Agency's (JMA) Storm Surge Model and WXTide software. Storm surge maps for the entire Philippines and time series plots for observation points in areas along the path of the typhoon were produced. Storm tide heights between one and five meters were also predicted for 68 coastal areas two days prior to Haiyan's landfall. A storm surge inundation map showing the extent of coastal flooding for Tacloban City, Leyte, one of the most severely affected areas by the typhoon, was generated using FLO-2D software. This was validated using field data such as high water marks, eyewitness accounts from locals, and information from media coverage. This map can be used as reference to determine danger zones and safe evacuation sites during similar events. Typhoon Haiyan generated one of the biggest and most devastating storm surge events in several decades, exacting a high death toll despite its early prediction. Lessons learned from this calamity and information contained in this work may serve as useful reference to mitigate the heavy impact of future storm surge events in the Philippines and elsewhere.

  10. State of the Art of Demand Surge Modeling

    NASA Astrophysics Data System (ADS)

    Olsen, A.; Porter, K.

    2009-04-01

    Among other phenomena, many insurance loss models estimate the increased losses in large-scale disasters--referred to here as catastrophes--compared to the losses in small-scale disasters. This amplification of loss has been traditionally and loosely called "demand surge," although there is a clear need for more specific terminology. Many factors have been identified as drivers of demand surge. First among them is the sudden and temporary increased demand for construction materials and labor that overwhelms local supplies. The purpose of the present research is to describe in qualitative terms the current understanding of demand surge in the broad sense of amplification of insured loss. Aspects of demand surge were observed following the 1886 Charleston, South Carolina, and 1906 San Francisco, U.S. earthquakes. More recently, the aftermaths of Cyclone Tracy, Hurricane Andrew, the Northridge Earthquake, the 1999 windstorms in France, the 2004-5 hurricane seasons on the Gulf Coast, and the 2007 floods in the U.K. all evidenced demand surge in one form or another. Each event highlights particular aspects of the broader demand-surge phenomena. In other words, there are general themes associated with demand surge, which have greater or lesser expression in each historic event. Pieces of the broader demand-surge phenomena have been described by mathematical models, with varying degrees of complexity. For example, researchers have used linear input-output or nonlinear computable general equilibrium models to describe the response of construction costs to a catastrophe. Ultimately the present research will include the gathering of evidence through interviews, field observations, reviews of academic and insurance industry literature, and data collection. This evidence will then inform and validate a general quantitative, mathematical model of the demand-surge process.

  11. Endotoxin disrupts the estradiol-induced luteinizing hormone surge: interference with estradiol signal reading, not surge release.

    PubMed

    Battaglia, D F; Beaver, A B; Harris, T G; Tanhehco, E; Viguié, C; Karsch, F J

    1999-06-01

    Three experiments were conducted to investigate whether the immune/inflammatory stimulus endotoxin disrupts the estradiol-induced LH surge of the ewe. Ovariectomized sheep were set up in an artificial follicular phase model in which luteolysis is simulated by progesterone withdrawal and the follicular phase estradiol rise is reproduced experimentally. In the first experiment, we tested the hypothesis that endotoxin interferes with the estradiol-induced LH surge. Ewes were either infused with endotoxin (300 ng/kg/h, i.v.) for 30 h beginning at onset of a 48-h estradiol stimulus or sham infused as a control. Endotoxin significantly delayed the time to the LH surge (P < 0.01), but did not alter surge amplitude, duration, or incidence. The second experiment tested the hypothesis that the delaying effects of endotoxin on the LH surge depend on when endotoxin is introduced relative to the onset of the estradiol signal. Previous work in the ewe has shown that a 14-h estradiol signal is adequate to generate GnRH and LH surges, which begin 6-8 h later. Thus, we again infused endotoxin for 30 h, but began it 14 h after the onset of the estradiol signal. In contrast to the first experiment, endotoxin given later had no effect on any parameter of the LH surge. In the third experiment, we tested the hypothesis that endotoxin acts during the first 14 h to disrupt the initial activating effects of estradiol. Estradiol was delivered for just 14 h, and endotoxin was infused only during this time. Under these conditions, endotoxin blocked the LH surge in five of eight ewes. In a similar follow-up study, endotoxin again blocked the LH surge in six of seven ewes. We conclude that endotoxin can disrupt the estradiol-induced LH surge by interfering with the early activating effects of the estradiol signal during the first 14 h (reading of the signal). In contrast, endotoxin does not disrupt later stages of signal processing (i.e. events during the interval between estradiol signal

  12. High latitude helical surge of May 22, 1989

    NASA Astrophysics Data System (ADS)

    Okten, Adnan; Cakmak, Hikmet

    1990-08-01

    A helical surge (S 72, W 90) was recorded by a monochromatic filter at the University Observatory of Istanbul. It is a significant one at a very high latitude and without any center of activity. A sequence of the filtergrams showed some condensed points from which the motions of the plasma are traced. Different velocities were determined on each of the branches of the helical surge during its evolution. The surge reached its maximum height of 298,000 km, and the maximum velocity of this upper region was 250 km/s.

  13. Pressure surge reflector for pipe type cable system

    SciTech Connect

    Chu, H.; El Badaly, H.A.; Ghafurian, R. ); Aabo, T.; Ringlee, R.R.; Williams, J.A. ); Melcher, J. )

    1990-04-01

    This paper describes work performed on the development and testing of a pressure surge reflector, designed to reduce the pressure seen at potheads during an electrical failure in a pipe type cable system. The reflector is designed to protect the potheads from failing due to the pressure surge that may be large enough to fracture the porcelain, particularly when the electrical failure is physically close to the pothead. Test results show that the prototype reflector will lower the pressure significantly, bringing the pressure surge below the factory pressure test level for standard potheads.

  14. Storm surge and tide interaction: a complete paradigm

    NASA Astrophysics Data System (ADS)

    Horsburgh, Kevin; Williams, Jane; Proctor, Robert

    2014-05-01

    Globally, 200 million people live on coastal floodplains and about 1 trillion worth of assets lie within 1 metre of mean sea level. Any change in the statistics of flood frequency or severity would impact on economic and social systems. It is therefore crucial to understand the physical drivers of extreme storm surges, and to have confidence in datasets used for extreme sea level statistics. Much previous research has focussed on the process of tide-surge interaction, and it is now widely accepted that the physical basis of tide-surge interaction is that a phase shift of the tidal signal represents the effect of the surge on the tide. The second aspect of interaction is that shallow water momentum considerations imply that differing tidal states should modulate surge generation: wind stress should have greater surge-generating potential on lower tides. This has been shown previously by analytical models but not as yet confirmed by fully non-linear models of the continental shelf. We present results from an operational model of the European shelf that demonstrate that tidal range does have an effect on the surges generated. The cycle-integrated effects of wind stress (i.e. the skew surge) are generally greater when tidal range is low. Our results contradict the absence of any such correlation observed in the complete record of UK tide gauge data. This suggests that whilst the modulating effect of the tide on the skew surge (the time-independent difference between peak prediction and observations) is significant, the difference between individual storms is dominant. This implies that forecasting systems must predict salient detail of the most intense storms. A further implication is that operational models need to simulate tides with acceptable accuracy at all coastal locations. We extend our model analysis to show that the same modulation of storm surges (by tidal conditions) applies to tropical cyclones. We conduct simulations using a mature operational storm surge

  15. Surge-like behavior at the non-surge type Matanuska Glacier, Alaska

    NASA Astrophysics Data System (ADS)

    Furuya, M.; Abe, T.

    2014-12-01

    Seasonal glacier velocity changes are attributed to subglacial slip associated with water pressure changes that occur because of the seasonal variability of meltwater input. Abe and Furuya (2014) reported winter speed-up signals and their downglacier propagation at a number of glaciers near the border of Alaska and Yukon, based on ALOS/PALSAR radar image analyses. Here we perform the similar analyses at the Chugach mountain range of South Central Alaska, and report the spatial-temporal evolution of the Matanuska Glacier. Matanuska Glacier is the largest accessible glacier in Alaska with its nearly 40 km length and 5 km width near the terminus. Comparing the winter velocity images in 2007, 2008 and 2010, those in 2010 were about 1.5-2 times faster than those during the previous two years. In addition, comparing the fall and winter velocities, winter velocities were apparently faster at every 2007-2008, 2009-2010, and 2010-2011 season. These data indicate winter speed-up or mini-surge signals even at a temperate and non-surgetype Matanuska Glacier. We also examine the spatial-temporal elevation changes, using data from the LiDAR altimeter in the Icebridge mission, and found significant elevation increase near the terminus. Winter speed-up may not be uncommon at Alaskan/Yukon glaciers. Lingle and Fatland (2003) detected faster speed in winter than in fall at non-surging Seward Glacier in the St. Elias Mountains; this is the only published and unambiguous report of winter speed-up, to our knowledge. Combined with earlier glacier hydrological studies, Lingle and Fatland proposed englacial water storage and gravity-driven water flow toward the bed in winter regardless of whether a given glacier is surge-type or not, and considered that the capacity of englacial water storage would control if a given glacier was surge-type or not. We consider that our measurements are complementary to Lingle and Fatland's observations and lend further support for their hypothesis. Basal

  16. Semidiurnal perturbations to the surge of Hurricane Sandy

    NASA Astrophysics Data System (ADS)

    Valle-Levinson, Arnoldo; Olabarrieta, Maitane; Valle, Alvaro

    2013-05-01

    Hurricane Sandy drove storm surges throughout the eastern seaboard of the United States, from Miami to Maine, at the end of October 2012. The surge was particularly high (>3 m) in coastal New York. In the southeastern United States, the surge was <1 m but had striking semidiurnal perturbations that reached a range of ~0.5 m in northern Florida and southern Georgia. These oscillations are typically not considered in surge forecasts and their origin needs to be understood for future forecasts. Analytical and numerical approaches indicated that semidiurnal perturbations arose from an interaction between astronomical tide and wind forcing. This combination of forcing caused phase shifts between incident and reflected tidal waves that customarily produce quasi-standing tidal conditions in the area. Atmospheric forcing of sufficient strength, which threshold remains to be established, disrupted such quasi-standing tidal behavior through Coriolis accelerations and triggered the semidiurnal perturbations.

  17. Semidiurnal perturbations to the surge of Hurricane Sandy

    NASA Astrophysics Data System (ADS)

    Valle-Levinson, Arnoldo; Olabarrieta, Maitane; Valle, Alvaro

    2013-04-01

    Hurricane Sandy drove storm surges throughout the eastern seaboard of the United States, from Miami to Maine, at the end of October 2012. The surge was particularly high (>3 m) in coastal New York. In the southeastern United States, the surge was <1 m but had striking semidiurnal perturbations that reached a range of ~0.5 m in northern Florida and southern Georgia. These oscillations are typically not considered in surge forecasts and therefore, it is essential to understand their origin for future forecasts. Analytical and numerical approaches indicated that semidiurnal perturbations arose from an interaction between astronomical tide and atmospheric forcing from wind and barometric pressure. This combination of forcing caused phase shifts between incident and reflected tidal waves that customarily produce quasi-standing tidal conditions in the area. Atmospheric forcing of sufficient strength, which threshold remains to be established, disrupted such quasi-standing tidal behavior and triggered the semidiurnal perturbations.

  18. 2. FOREMAN'S HOUSE, SURGE TANK AND TOP OF POWERHOUSE. VIEW ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. FOREMAN'S HOUSE, SURGE TANK AND TOP OF POWERHOUSE. VIEW TO EAST-NORTHEAST. - Rainbow Hydroelectric Facility, On north bank of Missouri River 2 miles Northeast of Great Falls, & end of Rainbow Dam Road, Great Falls, Cascade County, MT

  19. 5. HOUSE No. 16 AND SURGE TANK. ROOF OF POWERHOUSE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. HOUSE No. 16 AND SURGE TANK. ROOF OF POWERHOUSE IN BACKGROUND. VIEW TO NORTHEAST. - Rainbow Hydroelectric Facility, On north bank of Missouri River 2 miles Northeast of Great Falls, & end of Rainbow Dam Road, Great Falls, Cascade County, MT

  20. AERIAL PHOTO, LOOKING SOUTH, SHOWING POWERHOUSE, SURGE TANK, TRANSFORMER YARD, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    AERIAL PHOTO, LOOKING SOUTH, SHOWING POWERHOUSE, SURGE TANK, TRANSFORMER YARD, GLINES DAM, AND LAKE MILLS RESERVOIR. PHOTO BY JET LOWE, HAER, 1995. - Elwha River Hydroelectric System, Glines Hydroelectric Dam & Plant, Port Angeles, Clallam County, WA

  1. GLINES POWERHOUSE, TAILRACE, AND SURGE TANK WITH TRANSFORMER YARD IN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    GLINES POWERHOUSE, TAILRACE, AND SURGE TANK WITH TRANSFORMER YARD IN FOREGROUND; DAM AND RESERVOIR TO SOUTH. PHOTO BY JET LOWE, HAER, 1995. - Elwha River Hydroelectric System, Glines Hydroelectric Dam & Plant, Port Angeles, Clallam County, WA

  2. VIEW OF PENSTOCK AND SURGE TANK LEADING INTO SOUTH SIDE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF PENSTOCK AND SURGE TANK LEADING INTO SOUTH SIDE OF ELWHA POWERHOUSE. PHOTO BY JET LOWE, HAER, 1995. - Elwha River Hydroelectric System, Elwha Hydroelectric Dam & Plant, Port Angeles, Clallam County, WA

  3. GENERAL VIEW TO SOUTH OF WESTBANK SPILLWAY, PENSTOCK, SURGE TANK, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    GENERAL VIEW TO SOUTH OF WEST-BANK SPILLWAY, PENSTOCK, SURGE TANK, AND ELWHA POWERHOUSE. PHOTO BY JET LOWE, HAER, 1995. - Elwha River Hydroelectric System, Elwha Hydroelectric Dam & Plant, Port Angeles, Clallam County, WA

  4. VIEW TO EAST FROM HILLTOP: SURGE TANK AND TRANSFORMER YARD, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW TO EAST FROM HILLTOP: SURGE TANK AND TRANSFORMER YARD, WITH POWERHOUSE AND RIVER BELOW. PHOTO BY JET LOWE, HAER, 1995. - Elwha River Hydroelectric System, Glines Hydroelectric Dam & Plant, Port Angeles, Clallam County, WA

  5. VIEW OF SURGE TANK AND TRANSFORMER YARD FROM HILL ABOVE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF SURGE TANK AND TRANSFORMER YARD FROM HILL ABOVE POWERHOUSE. PHOTO BY JET LOWE, HAER, 1995. - Elwha River Hydroelectric System, Glines Hydroelectric Dam & Plant, Port Angeles, Clallam County, WA

  6. VIEW TO NORTH OF ELWHA RIVER, POWERHOUSE, SURGE TANK, AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW TO NORTH OF ELWHA RIVER, POWERHOUSE, SURGE TANK, AND PENSTOCK. PHOTO BY JET LOWE, HAER, 1995. - Elwha River Hydroelectric System, Elwha Hydroelectric Dam & Plant, Port Angeles, Clallam County, WA

  7. VIEW TO SOUTHWEST OF PENSTOCK AND SURGE TANK ABOVE GLINES ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW TO SOUTHWEST OF PENSTOCK AND SURGE TANK ABOVE GLINES POWERHOUSE. PHOTO BY JET LOWE, HAER, 1995. - Elwha River Hydroelectric System, Glines Hydroelectric Dam & Plant, Port Angeles, Clallam County, WA

  8. DETAIL OF TWO PENSTOCKS EXITING SURGE TANK TOWARD THE TURBINES ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DETAIL OF TWO PENSTOCKS EXITING SURGE TANK TOWARD THE TURBINES FOR GENERATORS #3 AND #4. PHOTO BY JET LOWE, HAER, 1995. - Elwha River Hydroelectric System, Elwha Hydroelectric Dam & Plant, Port Angeles, Clallam County, WA

  9. Zika-Linked Birth Defects Surge in Colombia: CDC

    MedlinePlus

    ... page: https://medlineplus.gov/news/fullstory_162464.html Zika-Linked Birth Defects Surge in Colombia: CDC Study ... born with devastating birth defects linked to the Zika virus is no longer confined to Brazil, a ...

  10. Why Teen Mental Ability Surges While Brain Shrinks

    MedlinePlus

    ... 166310.html Why Teen Mental Ability Surges While Brain Shrinks Researchers say they may have answer to ... answer to a persistent and quirky puzzle about brain development. They've long known that the brain's ...

  11. Active surge control for variable speed axial compressors.

    PubMed

    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.

  12. Modeling Storm Surge Risk to Surface and Groundwater Resources

    NASA Astrophysics Data System (ADS)

    Baig, S.

    2008-05-01

    It is a fact — regularly repeated by the National Hurricane Center — that, along the immediate coast the greatest threat to life and property associated with a land-falling tropical cyclone is the accompanying storm surge. Statistical tabulation of historical storms provides insufficient guidance to even partially describe this risk. Recourse must be made to numerical modeling to fully describe the potential storm surge inundation. For the entire hurricane-prone coastline and contiguous inland areas for which it is responsible, the U.S. National Weather Service has modeled potential storm surge inundation. In addition to highlighting the direct risk to water resources, these data can be used to assist in siting and guide remediation of infrastructure and potentially contaminating facilities. This talk will describe the NWS model and methods used to calculate the storm surge data, and will demonstrate their utility.

  13. U.S. Glaucoma Cases Expected to Surge by 2030

    MedlinePlus

    ... https://medlineplus.gov/news/fullstory_162924.html U.S. Glaucoma Cases Expected to Surge by 2030 Routine eye ... 6, 2017 FRIDAY, Jan. 6, 2017 (HealthDay News) -- Glaucoma affects more than 3 million Americans, but that ...

  14. Surging glaciers in Iceland - research status and future challenges

    NASA Astrophysics Data System (ADS)

    Ingolfsson, Olafur

    2013-04-01

    Twenty six Icelandic outlet glaciers, ranging from 0.5-1.500 km2, are known to surge, with terminal advances ranging from of few tens of meters to about 10 km. The geomorphic signatures of surges vary, from large-scale folded and thrusted end moraine systems, extensive dead-ice fields and drumlinized forefields to drift sheets where fast ice-flow indicators are largely missing. Case studies from the forefields of Brúarjökull, Eyjabakkajökull and Múlajökull surging glaciers will be presented. At Brúarjökull, extremely rapid ice flow during surge was sustained by overpressurized water causing decoupling beneath a thick sediment sequence that was coupled to the glacier. The ice-marginal position of the 1890 surge is marked by a sedimentary wedge formed within five days and a large moraine ridge that formed in about one day ("instantaneous end-moraine"). Three different qualitative and conceptual models are required to explain the genesis of the Eyjabakkajökull moraines: a narrow, single-crested moraine ridge at the distal end of a marginal sediment wedge formed in response to decoupling of the subglacial sediment from the bedrock and associated downglacier sediment transport; large lobate end moraine ridges with multiple, closely spaced, asymmetric crests formed by proglacial piggy-back thrusting; moraine ridges with different morphologies may reflect different members of an end moraine continuum. A parallel study highlighting the surge history of Eyjabakkajökull over the last 4400 years suggests climate control on surge frequencies. The Múlajökull studies concern an active drumlin field (>100 drumlins) that is being exposed as the glacier retreats. The drumlins form through repeated surges, where each surge causes deposition of till bed onto the drumlin while similtaneously eroding the sides. Finally, a new landsystem model for surging North Iceland cirque glaciers will be introduced. References Benediktsson,I. Ö., Schomacker, A., Lokrantz, H. & Ing

  15. 14 CFR 33.65 - Surge and stall characteristics.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... § 33.5(b), starting, a change of power or thrust, power or thrust augmentation, limiting inlet air distortion, or inlet air temperature may not cause surge or stall to the extent that flameout, structural...

  16. 14 CFR 33.65 - Surge and stall characteristics.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... § 33.5(b), starting, a change of power or thrust, power or thrust augmentation, limiting inlet air distortion, or inlet air temperature may not cause surge or stall to the extent that flameout, structural...

  17. 14 CFR 33.65 - Surge and stall characteristics.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... § 33.5(b), starting, a change of power or thrust, power or thrust augmentation, limiting inlet air distortion, or inlet air temperature may not cause surge or stall to the extent that flameout, structural...

  18. Thermospheric poleward wind surge at midlatitudes during great storm intervals

    NASA Astrophysics Data System (ADS)

    Zhang, Shun-Rong; Erickson, Philip J.; Foster, John C.; Holt, John M.; Coster, Anthea J.; Makela, Jonathan J.; Noto, John; Meriwether, John W.; Harding, Brian J.; Riccobono, Juanita; Kerr, Robert B.

    2015-07-01

    We report a significant poleward surge in thermospheric winds at subauroral and midlatitudes following the 17-18 March 2015 great geomagnetic storm. This premidnight surge is preceded by strong westward winds. These disturbances were observed over three sites with geodetic latitudes 35-42°N in the American sector by Fabry-Perot interferometers at 630 nm wavelength. Prior to the wind disturbances, subauroral polarization streams (SAPS) were measured by the Millstone Hill incoherent scatter radar between 20 and 02 UT. We identify the observed neutral wind variations as driven by SAPS, through a scenario where strong ion flows cause a westward neutral wind, subsequently establishing a poleward wind surge due to the poleward Coriolis force on that westward wind. These regional disturbances appear to have prevented the well-known storm time equatorward wind surge from propagating into low latitudes, with the consequence that the classic disturbance dynamo mechanism failed to occur.

  19. 27. EXTENSION OF SURGE CHAMBER AND AIR PIPES TO PRESSURE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    27. EXTENSION OF SURGE CHAMBER AND AIR PIPES TO PRESSURE LINE, HIGHLINE PUMPING PLANT. December 11, 1920 - Highline Canal & Pumping Station, South side of Salt River between Tempe, Phoenix & Mesa, Tempe, Maricopa County, AZ

  20. Storm Surge Flood Hazards of Hurricane Katrina 2005

    NASA Astrophysics Data System (ADS)

    Li, L.; Daneshvaran, S.; Jakubowski, S.

    2008-05-01

    . Flooding due to hurricane storm surge is one of the most damaging natural disasters in tropical and sub-tropical coastal regions. Storm surge peril can cause catastrophic loss to coastal properties and loss of life. Estimated hurricane flood risk is often statistically-based and relies on historical data. It provides catastrophic loss and risk information for the event as a whole, but lacks geographical detail. The purpose of this study is to analyze hurricane-induced storm surge flood damage using a grid-based numerical model. Storm surge flood damage due to Hurricane Katrina 2005 is presented as a case study. In order to analyze the resulting hazard from Hurricane Katrina, the United States National Weather Service's operational storm surge model, SLOSH (Sea, Lake and Overland Surges from Hurricanes) was used to predict the maximum storm surge surface using track data from meteorological observations. Local inundation is computed using the flood water depth with the ground elevation above the mean sea level. Residential exposure is estimated using total number of housing units damaged by flood water in each US census block in a grid of 0.01 by 0.01 degrees for hurricane Katrina in 2005. The modeled results for the storm surge inundation and the estimated number of housing units damaged by hurricane Katrina are compared with the extensive field observations by US Geological Survey and FEMA in the counties along the Gulf Coast in the three impacted states of Alabama, Mississippi and Louisiana. The modeled surge results are compared and contrasted with high water mark observations, where available. Storm surge losses in residential construction are highly sensitive to location and are best evaluated at a fine spatial resolution. This paper presents the analysis of the catastrophic flood risk based on the magnitude of hurricane storm surge flood depth on a local scale of US census blocks. The framework presented here is analytically-derived and can be used to

  1. Typhoon storm surge disaster and its forecasting in China

    SciTech Connect

    Wang Xinian; Ye Lin; Bao Chenglan

    1993-12-31

    This paper reviews new technologies for determining storm surges potential along China`s coastlines. The new monitoring stations and computer programs allow for the Chinese government to make predictions on the height of the storm surges and the effects that this will have on coastal flooding and stability and safety of offshore platforms. The paper reviews the history of the system and the numerical forecasting results generated by this program.

  2. Bed forms in base-surge deposits: lunar implications.

    PubMed

    Fisher, R V; Waters, A C

    1969-09-26

    Undulating dunelike deposits of surface debris, widespread over parts of the lunar landscape, are similar in form but greater in size than base-surge deposits found in many maar volcanoes and tuff rings on Earth. The bed forms of base-surge deposits develop by the interaction of the bed materials with those in the current passing overhead. Therefore the "patterned ground" produced differs from that formed by ballistic fallout.

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

    PubMed

    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.

  4. Substorm simulation: Formation of westward traveling surge

    NASA Astrophysics Data System (ADS)

    Ebihara, Y.; Tanaka, T.

    2015-12-01

    Auroral substorm expansion is characterized by initial brightening of aurora, followed by a bulge expanding in all directions, and a westward traveling surge (WTS). On the basis of the result obtained by a global magnetohydrodynamic simulation, we propose a scenario for the onset and the subsequent formation of WTS. (1) Near-Earth neutral line releases magnetic tension in the near-Earth plasma sheet to compress plasma and accelerate it earthward. (2) Earthward, perpendicular flow is converted to parallel flow in the near-Earth tail region. (3) Plasma moves earthward parallel to a field line. The plasma pressure is additionally enhanced at off-equator with an expanding slow-mode variation. (4) Flow vorticities coexist near the off-equatorial high-pressure region. Resultant field-aligned current (FAC) is connected to the ionosphere, which may manifest initial brightening. (5) Due to continued earthward flow, the high-plasma pressure region continues to expand to the east and west. (6) The ionospheric conductivity continues to increase in the upward FAC region, and the conductivity gradient becomes steeper. (7) The convergence of the Hall current gives rise to divergent electric field near the steep gradient of the conductivity. (8) Due to the divergent electric field, magnetospheric plasma moves counterclockwise at low altitude (in the Northern Hemisphere). (9) The additional flow vorticity generates a localized upward FAC at low altitudes, which may manifest WTS, and redistributes the ionospheric current and conductivity. Thus, WTS may be maintained in a self-consistent manner, and be a natural consequence of the overflow of the Hall current.

  5. Equatorial Mountain Torques and Cold Surges in a GCM

    NASA Astrophysics Data System (ADS)

    Lott, Francois; Mailler, Sylvain

    2014-05-01

    The dynamical relations between the equatorial atmospheric angular momentum, the equatorial mountain torque and the cold surges are analysed in a General Circultaion Model (GCM). First we show that the global equatorial atmospheric momentum budget is very well closed in the model which is a clear benefit when we compare with results from the NCEP reanalysis. We then confirm that the equatorial torques due to the Tibetan plateau, the Rockies and the Andes are well related to the cold surges developping over South Eastern China, North America, and the Southern South America respectively. For all these mountains, a peack in the Equatorial mountain torque component that points locally toward the pole preceeds by few days the development of the cold surges, yielding a predictive interest to our results. We also analyse the contributions to the torques of the parameterized mountain stresses and find that they contribute substantially. In experiments without the parameterized stresses, we also find that the explicit terms partly compensate the parameterized contributions to the torque, and the cold surges are not much affected. This shows that the cold surges can be well captured by models, providing that the synoptic conditions prior to their onset are well represented. The compensation between torques is nevertheless not complete and some weekening of the cold surges is found when the mountain forcings are reduced. This illustrates how the exact torques are needed at a given time to produce the correct synoptic scale dynamics at a later stage.

  6. The role of mangroves in attenuating storm surges

    USGS Publications Warehouse

    Zhang, Keqi; Liu, Huiqing; Li, Yuepeng; Xu, Hongzhou; Shen, Jian; Rhome, Jamie; Smith, J.

    2012-01-01

    Field observations and numerical simulations indicate that the 6-to-30-km-wide mangrove forest along the Gulf Coast of South Florida effectively attenuated stormsurges from a Category 3 hurricane, Wilma, and protected the inland wetland by reducing an inundation area of 1800 km2 and restricting surge inundation inside the mangrove zone. The surge amplitude decreases at a rate of 40–50 cm/km across the mangrove forest and at a rate of 20 cm/km across the areas with a mixture of mangrove islands with open water. In contrast, the amplitudes of stormsurges at the front of the mangrove zone increase by about 10–30% because of the "blockage" of mangroves to surge water, which can cause greater impacts on structures at the front of mangroves than the case without mangroves. The mangrove forest can also protect the wetlands behind the mangrove zone against surge inundation from a Category 5 hurricane with a fast forward speed of 11.2 m/s (25 mph). However, the forest cannot fully attenuate stormsurges from a Category 5 hurricane with a slow forward speed of 2.2 m/s (5 mph) and reduced surges can still affect the wetlands behind the mangrove zone. The effects of widths of mangrove zones on reducing surge amplitudes are nonlinear with large reduction rates (15–30%) for initial width increments and small rates (<5%) for subsequent width increments.

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

    SciTech Connect

    Russell H. Bonn; Sigifredo Gonzalez

    2000-04-11

    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.

  8. Surge-type glaciers in the Tien Shan (Central Asia)

    NASA Astrophysics Data System (ADS)

    Mukherjee, Kriti; Bolch, Tobias

    2016-04-01

    Surge-type glaciers in High Mountain Asia are mostly observed in Karakoram and Pamir. However, few surge-type glaciers also exist in the Tien Shan, but have not comprehensively studied in detail in the recent literature. We identified surge-type glaciers in the Tien Shan either from available literature or by manual interpretation using available satellite images (such as Corona, Hexagon, Landsat, SPOT, IRS) for the period 1960 to 2014. We identified 39 possible surge-type glaciers, showing typical characteristics like looped moraines. Twenty-two of them rapidly advanced during different periods or a surge was clearly described in the literature. For the remaining possible surge-type glaciers either the advance, in terms of time and length, were not mentioned in detail in the literature, or the glaciers have remained either stable or retreated during the entire period of our study. Most of the surge-type glaciers cluster in the Inner Tien Shan (especially in the Ak-Shiirak rage) and the Central Tien Shan, are in size and are facing North, West or North West. Pronounced surge events were observed for North Inylchek and Samoilowitsch glaciers, both of which are located in the Central Tien Shan. Samoilowitsch Glacier retreated by more than 3 km between 1960 (length ~8.9 km) and 1992 (~5.8 km), advanced by almost 3 km until 2006 and slightly retreated thereafter. The most pronounced advance occurred between 2000 and 2002. DEM differencing (based on SRTM3 data and stereo Hexagon and Cartosat-1 data) revealed a significant thickening in the middle reaches (reservoir area) of the glacier between 1973 and 2000 while the surface significantly lowered in the middle and upper parts of the glacier between 2000 and 2006. Hence, the ice mass was transferred to the lower reaches (receiving area) and caused the advance with a maximum thickening of more than 80 m. The ~30 km long North Inylchek Glacier retreated since 1943 and showed a very rapid advance of ~3.5 km especially in

  9. The influence of climate during and after a glacial surge - A comparison of the last two surges of Fridtjovbreen, Svalbard

    NASA Astrophysics Data System (ADS)

    Lønne, Ida

    2014-02-01

    Glacial surges are periods of fast flow, often limited in space and time, and driven by internal conditions which are not fully explained. The quantity and variety of documented case-studies and settings demonstrate that the critical variables are difficult to isolate. In an alternative approach, two surges from the same basin were compared at Fridtjovhamna; one of the few known sites where this is possible. Fridtjovbreen is a polythermal glacier that has been through two recent surges: the last event (1991-2002) occurred during an unusually warm period in the high Arctic, whereas the previous surge culminated in 1861, around the Little Ice Age when many Svalbard-glaciers had their maximum Holocene extent. Based on a multi-disciplinary study, processes and landforms from the two episodes were compared with respect to ice-front movement rates, formation and decay of ice-cored moraines and glacial meltwater drainage patterns. The study demonstrates that moraines and meltwater traces from the oldest surge, locally well preserved, provide excellent opportunities for reconstructing the behavior of the ice-mass. The last surge, however, took place during a period with ablation rates never seen at this latitude, and 10 years after the maximum extent, the deglaciated areas onshore hardly show traces from the event.

  10. Observing Storm Surges from Space: A New Opportunity

    NASA Astrophysics Data System (ADS)

    Han, Guoqi; Ma, Zhimin; Chen, Dake; de Young, Brad; Chen, Nancy

    2013-04-01

    Coastal tide gauges can be used to monitor variations of a storm surge along the coast, but not in the cross-shelf direction. As a result, the cross-shelf structure of a storm surge has rarely been observed. In this study we focus on Hurricane Igor-induced storm surge off Newfoundland, Canada. Altimetric observations at about 2:30, September 22, 2010 UTC (hours after the passage of Hurricane Igor) reveal prominent cross-shelf variation of sea surface height during the storm passage, including a large nearshore slope and a mid-shelf depression. A significant coastal surge of 1 m derived from satellite altimetry is found to be consistent with tide-gauge measurements at nearby St. John's station. The post-storm sea level variations at St. John's and Argentia are argued to be associated with free equatorward-propagating continental shelf waves (with phase speeds of 11-13 m/s), generated along the northeast Newfoundland coast hours after the storm moved away from St. John's. The cross-shelf e-folding scale of the shelf wave was estimated to be ~100 km. We further show approximate agreement of altimetric and tide-gauge observations in the Gulf of Mexico during Hurricane Katrina (2005) and Isaac (2012). The study for the first time in the literature shows the robustness of satellite altimetry to observe storm surges, complementing tide-gauge observations for the analysis of storm surge characteristics and for the validation and improvement of storm surge models.

  11. Developing health system surge capacity: community efforts in jeopardy.

    PubMed

    Felland, Laurie E; Katz, Aaron; Liebhaber, Allison; Cohen, Genna R

    2008-06-01

    Since Sept. 11, 2001, communities have responded to the federal call to enhance health care surge capacity--the space, supplies, staffing and management structure to care for many injured or ill people during a terrorist attack, natural disaster or infectious disease pandemic. Communities with varied experience handling emergencies are building broad surge capacity, including transportation, communication, hospital care and handling mass fatalities, according to a new study by the Center for Studying Health System Change (HSC). Communities rely on federal funding to help coordinate and plan across agencies and providers, conduct training and drills, recruit volunteers, and purchase equipment and stockpile supplies. The current federal focus on pandemic influenza has helped prepare for all types of emergencies, although at times communities struggle with fragmented and restrictive funding requirements. Despite progress, communities face an inherent tension in developing surge capacity. The need for surge capacity has increased at the same time that daily health care capacity has become strained, largely because of workforce shortages, reimbursement pressures and growing numbers of uninsured people. Payers do not subsidize hospitals to keep beds empty for an emergency, nor is it practical for trained staff to sit idle until a disaster hits. To compensate, communities are trying to develop surge capacity in a manner that supports day-to-day activities and stretches existing resources in an emergency. Many of these efforts--including integrating outpatient providers, expanding staff roles and adapting standards of care during a large-scale emergency--require greater coordination, guidance and policy support. As time passes since 9/11 and Hurricane Katrina, federal funding for surge capacity has waned, and communities are concerned about losing surge capacity they have built.

  12. A High Density Storm Surge Monitoring Network: Evaluating the Ability of Wetland Vegetation to Reduce Storm Surge

    NASA Astrophysics Data System (ADS)

    Lawler, S.; Denton, M.; Ferreira, C.

    2013-12-01

    Recent tropical storm activity in the Chesapeake Bay and a potential increase in the predicted frequency and magnitude of weather systems have drawn increased attention to the need for improved tools for monitoring, modeling and predicting the magnitude of storm surge, coastal flooding and the respective damage to infrastructure and wetland ecosystems. Among other forms of flood protection, it is believed that coastal wetlands and vegetation can act as a natural barrier that slows hurricane flooding, helping to reduce the impact of storm surge. However, quantifying the relationship between the physical process of storm surge and its attenuation by wetland vegetation is an active area of research and the deployment of in-situ measuring devices is crucial to data collection efforts in this field. The United States Geological Survey (USGS) mobile storm-surge network has already successfully provided a framework for evaluating hurricane induced storm surge water levels on a regional scale through the use of in-situ devices installed in areas affected by storm surge during extreme events. Based on the success of the USGS efforts, in this study we adapted the monitoring network to cover relatively small areas of wetlands and coastal vegetation with an increased density of sensors. Groups of 6 to 10 water level sensors were installed in sites strategically selected in three locations on the Virginia coast of the lower Chesapeake Bay area to monitor different types of vegetation and the resulting hydrodynamic patterns (open coast and inland waters). Each group of sensors recorded time series data of water levels for both astronomical tide circulation and meteorological induced surge. Field campaigns were carried out to survey characteristics of vegetation contributing to flow resistance (i.e. height, diameter and stem density) and mapped using high precision GPS. A geodatabase containing data from field campaigns will support the development and calibration of

  13. Storm surge propagation in Galveston Bay during Hurricane Ike

    NASA Astrophysics Data System (ADS)

    Rego, João L.; Li, Chunyan

    2010-09-01

    We studied Hurricane Ike's storm surge along the Texas-Louisiana coast using the fully nonlinear Finite-Volume Coastal Ocean Model (FVCOM, by Chen et al., 2003) with a high-resolution unstructured mesh. The model was validated with USGS surge data collected during Hurricane Ike. This study focused on 1) how the surge wave propagates into and within Galveston Bay and 2) the importance of the bay's barrier system. Ike's coastal surge propagated alongshore due east towards Louisiana, partly because of Bolivar Peninsula, which, together with Galveston Island, provided a barrier protecting the bay. In the upper bay, a west-east oscillation of water surface gradient of about 0.08 m/km was found and studied. We then varied Bolivar Peninsula's topography for different simulations, examining the role of barrier islands on surge propagation into the bay. Results suggest that when the Peninsula's height (or volume) was reduced to about 45% of the original, with two breaches, the bay was exposed to dangerously high water levels almost as much as those if the Peninsula was leveled to just 0.05 m above the Mean Sea Level, underlining the nonlinear nature of this bay-barrier system.

  14. Surge Recovery Techniques for the Tevatron Cold Compressors

    NASA Astrophysics Data System (ADS)

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

    2006-04-01

    The Fermilab Tevatron cryogenic system utilizes high-speed centrifugal cold compressors, made by Ishikawajima-Harima Heavy Industries Co. Ltd. (IHI), for high-energy operations. 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.

  15. Surge recovery techniques for the Tevatron cold compressors

    SciTech Connect

    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.

  16. Sea surges around the Gulf of Lions and atmospheric conditions

    NASA Astrophysics Data System (ADS)

    Ullmann, A.; Pirazzoli, P. A.; Moron, V.

    2008-09-01

    This paper analyses sea surge variations measured at four tide-gauge stations (Port-Vendres, Sète, Grau-de-la-Dent and Marseille) almost evenly located around the Gulf of Lions (NorthWestern corner of Mediterranean Sea) and their relationships with local-scale winds and regional-scale atmospheric patterns (i.e. weather regimes). On the whole 20th century, more than 80% of sea surge > 20 cm occurs in winter and the analyses focus on October to March semester. There is a strong in-phase relationship between the four tide-gauge stations at hourly and daily time scales on the period 1986-1995. The highest sea surges in the Gulf of Lions are associated with a strong negative phase of the North Atlantic oscillation. Around 70% of sea surge > 40 cm at all stations occur during "Greenland Above" and "Blocking" weather regimes, when extratropical storms travelled on a southern track and are associated with onshore southerly winds that drag water toward the coast of the Gulf of Lions. Port-Vendres and mostly Marseille tide-gauge stations are also sensitive to northerly winds due to the local orientation of the coast. The frequency of southerly winds significantly increases since 1950, while the frequency of northerly winds decreases consistent with the increase of sea surges in the Gulf of Lions.

  17. Eyjabakkajokull Glacial Landsystem, Iceland: Geomorphic Impact of Multiple Surges

    NASA Astrophysics Data System (ADS)

    Ingolfsson, O.; Schomacker, A.; Benediktsson, I.

    2013-12-01

    A new glacial geomorphological map of the Eyjabakkajökull forefield in Iceland is presented. The map covers c. 60 km2 and is based on high-resolution aerial photographs recorded in August 2008 as well as field checking. Landforms are manually registered in a geographical information system (ArcGIS) based on inspection of orthorectified imagery and digital elevation models of the area. We mapped subglacially streamlined landforms such as flutes and drumlins on the till plain, supraglacial landforms such as ice-cored moraine, pitted outwash, and concertina eskers, and ice-marginal landforms such as the large, multi-crested 1890 surge end moraine and smaller single-crested end moraines. The glaciofluvial landforms are represented by outwash plains, minor outwash fans, and sinuous eskers. Extramarginal sediments were also registered and consist mainly of old sediments in wetlands or locally weathered bedrock. Eyjabakkajökull has behaved as a surge-type glacier for 2200 years; hence, the mapped landforms originate from multiple surges. Landforms such as large glaciotectonic end moraines, hummocky moraine, long flutes, crevasse-fill ridges, and concertina eskers are characteristic for surge-type glaciers. The surging glacier landsystem of Eyjabakkajökull serves as a modern analog to the landsystems of terrestrial paleo-ice streams.

  18. Cold surge: a sudden and spatially varying threat to health?

    PubMed

    Yang, Tse-Chuan; Wu, Pei-Chih; Chen, Vivian Yi-Ju; Su, Huey-Jen

    2009-05-01

    While cold surge is one of the most conspicuous features of the winter monsoon in East Asia, its impact on human health remains underexplored. Based on the definition by the Central Weather Bureau in Taiwan, we identified four cold surges between 2000 and 2003 and collected the cardiovascular disease mortality data 2 weeks before and 2 weeks after these events. We attempted to answer the following research questions: 1) whether the cold surges impose an adverse and immediate effect on cardiovascular mortality; 2) whether the people living in temperate zones have a higher tolerance of extreme temperature drop than those in the subtropics. With geographic weighting techniques, we not only found that the cardiovascular disease mortality rates increased significantly after the cold surges, but also discovered a spatially varying pattern of tolerance to cold surges. Even within a small study area such as Taiwan, human reaction to severe weather drop differs across space. Needless to say, in the U.S., these findings should be considered in redirecting policy to address populations living in warm places when extreme temperature drops occur.

  19. Prediction of storm surge using tropical cyclone information based on a global atmosphere model and a tide-surge model

    NASA Astrophysics Data System (ADS)

    Yuk, Jin-Hee; Kim, Kyeong Ok; Park, Junghyun; Joh, Minsu

    2017-04-01

    The south-eastern coast of Korea (the Republic of Korea) has often been damaged by storm surge and high waves due to the typhoon, therefore it is important to predict typhoon movement and storm surge accurately and quickly. We made an attempt to 1-way couple the Model for Prediction Across Scales (MPAS), a global atmosphere model, and the ADvanced CIRCulation model (ADCIRC), a tide-surge model, i.e., providing the atmosphere model's outputs for tide-surge model's forcing. The MPAS has the unstructured Voronoi meshes and allows higher-resolution for the target area, thus the variable mesh system based on the mesh resolutions of 15 km in the region of interest, the western Pacific region and 60 km in the entire model domain was built and was run for prediction of typhoon once a day during summer, July to September. The ADCIRC model also has a flexible unstructured mesh, thus the high-resolution with minimum mesh size of 50 m was formed in the south-eastern coast. The typhoon information such as typhoon track, maximum wind, minimum air pressure and radius of storm can be extracted from the atmosphere model output using the Geophysical Fluid Dynamics Laboratory (GFDL) vortex tracker, and then the tide-surge model calculates the storm surge using Holland type vortex model and the typhoon information produced by the atmosphere model and vortex tracker. In this study, this coupled model system was used to predict the storm surge due to typhoon Chaba that occurred in the beginning of October, 2016 and struck the south-eastern coast of Korea. The estimated typhoon Chaba (201618) track's distance error was less than 100 km in 48 hours and 200 km in 72 hours, thus this global atmosphere model shows a good performance to predict the typhoon movement and is also comparable to forecasting agencies such as KMA, JMA and JTWC. Generally, the storm surge due to typhoon Chaba was reproduced reasonably for the south-eastern sea of Korea. The modelling system acquired in this study can

  20. Pressure surge analysis in tanker loading/unloading systems

    SciTech Connect

    El-Oun, Z.; Stephens, P.

    1995-12-31

    Surge pressures are generated in any pipeline system where there is a sudden change in flow. This may be caused by either the opening or closing of a valve, the start up or shutdown of a pump or a combination of the two. If the pressure surge in the pipeline results in stresses in excess of the strength of the pipeline results in stresses in excess of the strength of the pipe or its components, then there may be a rupture leading to an oil spillage which could have major economic and environmental implications. Offshore loading/unloading facilities (cargo transfer systems) incorporating onshore tankage and pipework together with loading/unloading arrangements (via fixed jetty or CALM system) are in use worldwide and, in view of the fact that such systems are often composed of system components having different pressure ratings, susceptibility to damage due to excessive surge is a major factor to be considered in the design.

  1. Homogeneous record of Atlantic hurricane surge threat since 1923

    PubMed Central

    Grinsted, Aslak; Moore, John C.; Jevrejeva, Svetlana

    2012-01-01

    Detection and attribution of past changes in cyclone activity are hampered by biased cyclone records due to changes in observational capabilities. Here we construct an independent record of Atlantic tropical cyclone activity on the basis of storm surge statistics from tide gauges. We demonstrate that the major events in our surge index record can be attributed to landfalling tropical cyclones; these events also correspond with the most economically damaging Atlantic cyclones. We find that warm years in general were more active in all cyclone size ranges than cold years. The largest cyclones are most affected by warmer conditions and we detect a statistically significant trend in the frequency of large surge events (roughly corresponding to tropical storm size) since 1923. In particular, we estimate that Katrina-magnitude events have been twice as frequent in warm years compared with cold years (P < 0.02). PMID:23071336

  2. Homogeneous record of Atlantic hurricane surge threat since 1923.

    PubMed

    Grinsted, Aslak; Moore, John C; Jevrejeva, Svetlana

    2012-11-27

    Detection and attribution of past changes in cyclone activity are hampered by biased cyclone records due to changes in observational capabilities. Here we construct an independent record of Atlantic tropical cyclone activity on the basis of storm surge statistics from tide gauges. We demonstrate that the major events in our surge index record can be attributed to landfalling tropical cyclones; these events also correspond with the most economically damaging Atlantic cyclones. We find that warm years in general were more active in all cyclone size ranges than cold years. The largest cyclones are most affected by warmer conditions and we detect a statistically significant trend in the frequency of large surge events (roughly corresponding to tropical storm size) since 1923. In particular, we estimate that Katrina-magnitude events have been twice as frequent in warm years compared with cold years (P < 0.02).

  3. A global reanalysis of storm surges and extreme sea levels

    PubMed Central

    Muis, Sanne; Verlaan, Martin; Winsemius, Hessel C.; Aerts, Jeroen C. J. H.; Ward, Philip J.

    2016-01-01

    Extreme sea levels, caused by storm surges and high tides, can have devastating societal impacts. To effectively protect our coasts, global information on coastal flooding is needed. Here we present the first global reanalysis of storm surges and extreme sea levels (GTSR data set) based on hydrodynamic modelling. GTSR covers the entire world's coastline and consists of time series of tides and surges, and estimates of extreme sea levels. Validation shows that there is good agreement between modelled and observed sea levels, and that the performance of GTSR is similar to that of many regional hydrodynamic models. Due to the limited resolution of the meteorological forcing, extremes are slightly underestimated. This particularly affects tropical cyclones, which requires further research. We foresee applications in assessing flood risk and impacts of climate change. As a first application of GTSR, we estimate that 1.3% of the global population is exposed to a 1 in 100-year flood. PMID:27346549

  4. A global reanalysis of storm surges and extreme sea levels.

    PubMed

    Muis, Sanne; Verlaan, Martin; Winsemius, Hessel C; Aerts, Jeroen C J H; Ward, Philip J

    2016-06-27

    Extreme sea levels, caused by storm surges and high tides, can have devastating societal impacts. To effectively protect our coasts, global information on coastal flooding is needed. Here we present the first global reanalysis of storm surges and extreme sea levels (GTSR data set) based on hydrodynamic modelling. GTSR covers the entire world's coastline and consists of time series of tides and surges, and estimates of extreme sea levels. Validation shows that there is good agreement between modelled and observed sea levels, and that the performance of GTSR is similar to that of many regional hydrodynamic models. Due to the limited resolution of the meteorological forcing, extremes are slightly underestimated. This particularly affects tropical cyclones, which requires further research. We foresee applications in assessing flood risk and impacts of climate change. As a first application of GTSR, we estimate that 1.3% of the global population is exposed to a 1 in 100-year flood.

  5. A global reanalysis of storm surges and extreme sea levels

    NASA Astrophysics Data System (ADS)

    Muis, Sanne; Verlaan, Martin; Winsemius, Hessel C.; Aerts, Jeroen C. J. H.; Ward, Philip J.

    2016-06-01

    Extreme sea levels, caused by storm surges and high tides, can have devastating societal impacts. To effectively protect our coasts, global information on coastal flooding is needed. Here we present the first global reanalysis of storm surges and extreme sea levels (GTSR data set) based on hydrodynamic modelling. GTSR covers the entire world's coastline and consists of time series of tides and surges, and estimates of extreme sea levels. Validation shows that there is good agreement between modelled and observed sea levels, and that the performance of GTSR is similar to that of many regional hydrodynamic models. Due to the limited resolution of the meteorological forcing, extremes are slightly underestimated. This particularly affects tropical cyclones, which requires further research. We foresee applications in assessing flood risk and impacts of climate change. As a first application of GTSR, we estimate that 1.3% of the global population is exposed to a 1 in 100-year flood.

  6. A Field Study of Lightning Surges Propagating through Low-voltage Electric Appliances

    NASA Astrophysics Data System (ADS)

    Ishii, Tsunayoshi; Sakamoto, Yoshiki; Oguchi, Shuichi; Okabe, Shigemitsu

    In today's highly information-based society, lightning damage has a significant impact on an increasing number of electric appliances such as personal computers and facsimile machines. Lightning surge protection devices for electric appliances are on the market and concern for lightning protection has been increasing, but there are still many unknown aspects of lightning surges that propagate into residences. To provide effective lightning protection measures, clarification of surge propagation patterns is needed. The Tokyo Electric Power Company has observed the patterns of lightning surge propagation into houses using lightning surge waveform detectors installed at ordinary residences and obtained data on 30 lightning surge current waveforms between 2008 and 2009. This paper discusses various aspects of lightning surge currents propagating into low-voltage appliances, including home electric appliances, based on the lightning surge current waveform data obtained from lightning observations. The result revealed the patterns of lightning surge currents propagating into the ground and lines of low-voltage appliances.

  7. Community health facility preparedness for a cholera surge in Haiti.

    PubMed

    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.

  8. Effect of azilsartan versus candesartan on morning blood pressure surges in Japanese patients with essential hypertension.

    PubMed

    Rakugi, Hiromi; Kario, Kazuomi; Enya, Kazuaki; Sugiura, Kenkichi; Ikeda, Yoshinori

    2014-06-01

    Morning blood pressure (BP) surge is reported as a risk factor for cardiovascular events and end-organ damage independent of the 24-h BP level. Controlling morning BP surge is therefore important to help prevent onset of cardiovascular disease. We compared the efficacy of azilsartan and candesartan in controlling morning systolic BP (SBP) surges by analyzing relevant ambulatory BP monitoring data in patients with/without baseline BP surges. As part of a 16-week randomized, double-blind study of azilsartan (20-40 mg once daily) and candesartan (8-12 mg once daily) in Japanese patients with essential hypertension, an exploratory analysis was carried out using ambulatory BP monitoring at baseline and week 14. The effects of study drugs on morning BP surges, including sleep trough surge (early morning SBP minus the lowest night-time SBP) and prewaking surge (early morning SBP minus SBP before awakening), were evaluated. Patients with sleep trough surge of at least 35 mmHg were defined by the presence of a morning BP surge (the 'surge group'). Sleep trough surge and prewaking surge data were available at both baseline and week 14 in 548 patients, 147 of whom (azilsartan 76; candesartan 71) had a baseline morning BP surge. In surge group patients, azilsartan significantly reduced both the sleep trough surge and the prewaking surge at week 14 compared with candesartan (least squares means of the between-group differences -5.8 mmHg, P=0.0395; and -5.7 mmHg, P=0.0228, respectively). Once-daily azilsartan improved sleep trough surge and prewaking surge to a greater extent than candesartan in Japanese patients with grade I-II essential hypertension.

  9. Effect of azilsartan versus candesartan on morning blood pressure surges in Japanese patients with essential hypertension

    PubMed Central

    Kario, Kazuomi; Enya, Kazuaki; Sugiura, Kenkichi; Ikeda, Yoshinori

    2014-01-01

    Morning blood pressure (BP) surge is reported as a risk factor for cardiovascular events and end-organ damage independent of the 24-h BP level. Controlling morning BP surge is therefore important to help prevent onset of cardiovascular disease. We compared the efficacy of azilsartan and candesartan in controlling morning systolic BP (SBP) surges by analyzing relevant ambulatory BP monitoring data in patients with/without baseline BP surges. As part of a 16-week randomized, double-blind study of azilsartan (20–40 mg once daily) and candesartan (8–12 mg once daily) in Japanese patients with essential hypertension, an exploratory analysis was carried out using ambulatory BP monitoring at baseline and week 14. The effects of study drugs on morning BP surges, including sleep trough surge (early morning SBP minus the lowest night-time SBP) and prewaking surge (early morning SBP minus SBP before awakening), were evaluated. Patients with sleep trough surge of at least 35 mmHg were defined by the presence of a morning BP surge (the ‘surge group’). Sleep trough surge and prewaking surge data were available at both baseline and week 14 in 548 patients, 147 of whom (azilsartan 76; candesartan 71) had a baseline morning BP surge. In surge group patients, azilsartan significantly reduced both the sleep trough surge and the prewaking surge at week 14 compared with candesartan (least squares means of the between-group differences −5.8 mmHg, P=0.0395; and −5.7 mmHg, P=0.0228, respectively). Once-daily azilsartan improved sleep trough surge and prewaking surge to a greater extent than candesartan in Japanese patients with grade I–II essential hypertension. PMID:24710336

  10. Synchronous glacier surge events observed in the West Kunlun Shan, Xinjiang, China

    NASA Astrophysics Data System (ADS)

    Chudley, Tom; Willis, Ian

    2017-04-01

    High Mountain Asia is a major centre of glacier surge activity, but the precise surge mechanisms in the region are poorly understood. Satellite-based studies in the region describe unusual surge characteristics that appear to be explained poorly by either of the two classic surge mechanisms (hydrological and thermal surging) firmly established in the literature. Here, we present a record of surging in a ˜40 x 60 km zone of the West Kunlun Shan (WKS), Xinjiang, a poorly researched range ˜250 km northeast of the Karakoram. We use a combination of historic satellite imagery and cross-correlation feature tracking to expand the record of surging in the region and assess surge dynamics. We use the 1972—2016 Landsat satellite record to observe a total of 9 surge active phases in the past four decades. Of these, 2 occur prior to 2000, but the remaining 7 display a highly unusual near-synchronous surge onset in the 2006—2008 period. This synchronous surge behaviour has not previously been reported for discrete unconnected glaciers. Additionally, the surge characteristics showed similar surge characteristics to those observed in the Karakoram, notably low peak velocities (2—3 m day-1) reminiscent of thermal surges and short active phase periods (˜2-5 years) reminiscent of hydrological surges. We suggest that such observations are indicative of surging via a 'hydro-thermodynamic' mechanism, recently proposed for the Basin-C outlet of Austfonna, Svalbard. In this mechanism, high surface melt rates can raise the temperature of cold-based ice over relatively short timescales compared to thermal surges by rapidly transmitting energy to the base, facilitating enhanced flow by ice deformation. This hypothesis is supported by meteorological data, which show that the 2006-2008 period was marked by a series of all-time highs in seasonal temperatures in southern Xinjiang, suggesting that high surface melt is a valid mechanism by which these surges could have initiated.

  11. Discontinuous Galerkin methods for modeling Hurricane storm surge

    NASA Astrophysics Data System (ADS)

    Dawson, Clint; Kubatko, Ethan J.; Westerink, Joannes J.; Trahan, Corey; Mirabito, Christopher; Michoski, Craig; Panda, Nishant

    2011-09-01

    Storm surge due to hurricanes and tropical storms can result in significant loss of life, property damage, and long-term damage to coastal ecosystems and landscapes. Computer modeling of storm surge can be used for two primary purposes: forecasting of surge as storms approach land for emergency planning and evacuation of coastal populations, and hindcasting of storms for determining risk, development of mitigation strategies, coastal restoration and sustainability. Storm surge is modeled using the shallow water equations, coupled with wind forcing and in some events, models of wave energy. In this paper, we will describe a depth-averaged (2D) model of circulation in spherical coordinates. Tides, riverine forcing, atmospheric pressure, bottom friction, the Coriolis effect and wind stress are all important for characterizing the inundation due to surge. The problem is inherently multi-scale, both in space and time. To model these problems accurately requires significant investments in acquiring high-fidelity input (bathymetry, bottom friction characteristics, land cover data, river flow rates, levees, raised roads and railways, etc.), accurate discretization of the computational domain using unstructured finite element meshes, and numerical methods capable of capturing highly advective flows, wetting and drying, and multi-scale features of the solution. The discontinuous Galerkin (DG) method appears to allow for many of the features necessary to accurately capture storm surge physics. The DG method was developed for modeling shocks and advection-dominated flows on unstructured finite element meshes. It easily allows for adaptivity in both mesh ( h) and polynomial order ( p) for capturing multi-scale spatial events. Mass conservative wetting and drying algorithms can be formulated within the DG method. In this paper, we will describe the application of the DG method to hurricane storm surge. We discuss the general formulation, and new features which have been added to

  12. Probabilistic Storm Surge Hazard Assessment in the French West Indies

    NASA Astrophysics Data System (ADS)

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

    2016-12-01

    The French West Indies are prone to hurricanes formed over the warm tropical waters of the Atlantic Ocean and Caribbean Sea. These events can have great consequences in terms of human, property, and economic losses. Storm surge hazard assessment is therefore required to provide guidance to emergency managers and decision-makers. By combining statistical-deterministic approaches and wave-current coupled models, we assessed storm surge hazard in Guadeloupe and Martinique islands. We present here the methodology, the results, as well as the on-going work on the impact of climate change in the framework of the FEDER-funded project C3AF.

  13. Monitoring Inland Storm Surge and Flooding from Hurricane Rita

    USGS Publications Warehouse

    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.

  14. 4. ROOF OF TWOSTALL GARAGE, SURGE TANK, HOUSE No. 16, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. ROOF OF TWO-STALL GARAGE, SURGE TANK, HOUSE No. 16, RELIEF TANK IN BACKGROUND. VIEW TO SOUTH. - Rainbow Hydroelectric Facility, On north bank of Missouri River 2 miles Northeast of Great Falls, & end of Rainbow Dam Road, Great Falls, Cascade County, MT

  15. Hospital-Based Coalition to Improve Regional Surge Capacity

    PubMed Central

    Terndrup, Thomas E.; Leaming, James M.; Adams, R. Jerry; Adoff, Spencer

    2012-01-01

    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. PMID:23316266

  16. Modelling waves and surges during the 1953 storm.

    PubMed

    Wolf, J; Flather, R A

    2005-06-15

    Waves and sea levels have been modelled for the storm of 31 January-1 February 1953. Problems in modelling this event are associated with the difficulty of reconstructing wind fields and validating the model results with the limited data available from 50 years ago. The reconstruction of appropriate wind fields for surge and wave models is examined. The surges and waves are reproduced reasonably well on the basis of tide-gauge observations and the sparse observational information on wave heights. The maximum surge coincided closely in time with tidal high water, producing very high water levels along the coasts of the southern North Sea. The statistics of the 1953 event and the likelihood of recurrence are also discussed. Both surge and wave components were estimated to be approximately 1 in 50 year events. The maximum water level also occurred when the offshore waves were close to their maximum. The estimation of return period for the total water level is more problematic and is dependent on location. A scenario with the 1953 storm occurring in 2075, accounting for the effects of sea level rise and land movements, is also constructed, suggesting that sea level relative to the land could be 0.4-0.5m higher than in 1953 in the southern North Sea, assuming a rise in mean sea level of 0.4m.

  17. DETAIL OF PENSTOCK ENTERING SURGE TANK AND SOUTH SIDE OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DETAIL OF PENSTOCK ENTERING SURGE TANK AND SOUTH SIDE OF POWERHOUSE. 69-KV TRANSMISSION TOWERS WITH LIGHTENING ARRESTORS ARE SEEN ON HILLSIDE TO THE NORTH. PHOTO BY JET LOWE, HAER, 1995. - Elwha River Hydroelectric System, Elwha Hydroelectric Dam & Plant, Port Angeles, Clallam County, WA

  18. Study of surge current effects on solid tantalum capacitors

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Results are presented of a 2,000 hour cycled life test program conducted to determine the effect of short term surge current screening on approximately 47 micron f/volt solid tantalum capacitors. The format provides average values and standard deviations of the parameters, capacitance, dissipation factor, and equivalent series resistance at 120 Hz, 1KHz, abd 40 KHz.

  19. 97. Detail of surge tank and valves for Exciter penstocks ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    97. Detail of surge tank and valves for Exciter penstocks (which enter powerhouse below the air conditioning unit in center), looking north. Photo by Jet Lowe, HAER, 1989. - Puget Sound Power & Light Company, White River Hydroelectric Project, 600 North River Avenue, Dieringer, Pierce County, WA

  20. Hurricane Risk Assessment: Wind Damage and Storm Surge (Invited)

    NASA Astrophysics Data System (ADS)

    Lin, N.; Vanmarcke, E. H.; Emanuel, K.

    2010-12-01

    Hurricanes present major hazards for the United States. Associated with extreme winds, heavy rainfall, and storm surge, landfalling hurricanes often cause enormous structural damage to coastal regions. Risk assessment of hurricane-induced wind damage and storm surge is discussed. First, an innovative windborne debris risk model is presented. It is integrated into a next-generation structural vulnerability analysis to predict cumulative wind damage in residential developments, accounting for the interaction between debris damage and wind-pressure damage during storm passage, a major mechanism leading to structural failures during hurricanes. Second, a risk assessment model is introduced to estimate hurricane storm surge risk along the coast, particularly for data-scarce regions. It couples a statistical/deterministic hurricane model and the Advanced Circulation (ADCIRC) model with grids of various resolutions to simulate large numbers of synthetic surge events for statistical analysis. Basic properties of Poisson random measures are applied to develop the mathematical frameworks for both of these risk models, which can be applied to investigate climate change impact and provide the basis for policy-making related to loss mitigation.

  1. Spectral analysis of storm surge in Hong Kong Victoria Harbour

    NASA Astrophysics Data System (ADS)

    Tou, Stephen K. W.; Arumugam, K.

    Based on a linear model the dynamic characteristics of Victoria Harbour (Hong Kong) is obtained by means of spectral analysis of the storm surge hydrographs. The results show that the harbour is an ideal one which has a small gain factor and a flat response in the frequency range from 0 to 6 × 10 -5 Hz. The results also show that the power spectra possess the narrow band features which indicates that the periodic components associated with tidal motions are predominant over the random components. The power spectrum corresponding to a frequency of 2.3 × 10 -5 Hz is likely to be associated with the astronomical tides. The peaks in the power spectra at zero frequency suggest that the pumping mode of oscillations is dominant in a storm surge. This mode of oscillations represents the temporal variations in mean sea level. To demonstrate the full potential of the present model, more case studies should be conducted when surge as well as non-surge data are available.

  2. Assessment of Hospital Management and Surge Capacity in Disasters

    PubMed Central

    Shabanikiya, Hamidreza; Gorgi, Hasan Abolghasem; Seyedin, Hesam; Jafari, Mehdi

    2016-01-01

    Background Hospital administrators play a key role in the effective management of surge capacity in disasters, but there is little information available about the characteristics required to manage this. Objectives In this study, we aimed to identify characteristics of hospital administrators that are important in the effective management of surge capacity in disasters. Materials and Methods This was a qualitative study. Semi-structured purposive interviews were conducted with 28 hospital administrators who had experience working in surge situations in hospitals during disasters. Framework analysis was used to analyze the data. Results Three themes and 12 subthemes were identified. The themes were as follows: 1) crisis managerial characteristics, 2) personal characteristics, and 3) specific requirements. Conclusions In this study, some characteristics that had a positive impact on the success of a manager in a hospital surge situation were identified. These characteristics ought to be taken into account when appointing hospital administrators and designing training programs for hospital administrators with the aim of being better prepared to face disasters. PMID:27626015

  3. Aging assessment of surge protective devices in nuclear power plants

    SciTech Connect

    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.

  4. A remote tester for surge arresters: Final report

    SciTech Connect

    Shaw, J.H.

    1986-12-01

    Laboratory studies show that the most probable indication that a surge arrester is failing is electromagnetic energy emission. In field trials by eight utilities, a tester designed to detect radiofrequency emissions located defective arresters, but stray emissions in the environment limited its performance.

  5. Attribution of storm surge events in the Baltic Sea

    NASA Astrophysics Data System (ADS)

    Klehmet, Katharina; Burkhardt, Rockel

    2016-04-01

    In November 1995 and 2006 severe storm surges occurred along the German Baltic Sea coast. Water level heights of 1.8 m above sea level were observed at tide gauges in German coastal cities as e.g. Wismar and Flensburg. Within the attribution science an interesting aspect to consider is whether individual extreme events of e.g. heat waves, droughts or storm surges can be related to human-induced climate change or natural climate variability. The question arises whether these individual storm surges of 1995 and 2006 in the Baltic Sea have changed due to human influence on climate or whether the knowledge is still too vague to obtain robust information of attribution. We explore this question using two 15-member ensembles of Hadley Centre Global Environmental Model version 3-A (HadGEM3-A) as atmospheric forcing data for the regional ocean model TRIM-NP to downscale with 12.8 km spatial resolution and to calculate water level in the Baltic Sea. The ensemble of HadGEM3-A consists of two multi-decadal experiments from 1960-2013 - one with and one without anthropogenic forcings representing the actual and the natural climate respectively. This study, which is part of the EUCLEIA project (EUropean CLimate and weather Events: Interpretation and Attribution), will describe assessments of the human influence on the probability of occurrence of storm surge events in the German Baltic Sea.

  6. Increasing the highest storm surge in Busan harbor

    NASA Astrophysics Data System (ADS)

    Oh, Sang Myeong; Moon, Il-Ju; Kwon, Suk Jae

    2017-04-01

    One of the most pronounced effects of climate change in coastal regions is sea level rise and storm surges. Busan in particular, the fifth largest container handling port in the world, has suffered from serious storm surges and experienced a remarkable mean sea level (MSL) rise. This study investigates a long-term variation of annual maximum surge height (AMSH) using sea level data observed in Busan over 53 years (1962 2014). The decomposition of astronomical tides and surge components shows that the AMSH has increased 18 cm over 53 years (i.e., 3.5 mm/year), which is much larger than the MSL trend (2.5 mm/year) in Busan. This significant increase in AMSH is mostly explained by the increased intensity of landfall typhoons over the Korean peninsula (KP), which is associated with the increase of sea surface temperature and the decrease of vertical wind shear at mid-latitudes of the western North Pacific. In a projected future warming environment, the combination of an increasing MSL and AMSH will accelerate the occurrence of record-breaking extreme sea levels, which will be a potential threat in Busan harbor.

  7. SPH Simulation of Impact of a Surge on a Wall

    NASA Astrophysics Data System (ADS)

    Diwakar, Manoj Kumar; Mohapatra, Pranab Kumar; Tripathi, Shivam

    2014-05-01

    Structures located on the downstream of a dam are prone to impact of the surge due to dam break flow. Ramsden (1996) experimentally studied the run-up height on a vertical wall due to propagation of bore and surge on dry bed and measured their impact on the wall. Mohapatra et al. (2000) applied Navier Stokes equations to numerically study the impact of bore on vertical and inclined walls. They also obtained the evolution of surge on dry bed. In the present work, the impact of a surge wave due to dam break flow against the wall is modeled with a two-dimensional smoothed particle hydrodynamics (SPH) model. SPH is a mesh-free method that relies on the particle view of the field problem and approximates the continuity and momentum equations on a set of particles. The method solves the strong form of Navier-Stokes equations. The governing equations are solved numerically in the vertical plane. The propagation of the surge wave, its impact and the maximum run-up on the wall located at the boundary are analyzed. Surface profile, velocity field and pressure distributions are simulated. Non-dimensional run-up height obtained from the present numerical model is 0.86 and is in good agreement with the available experimental data of Ramsden (1996) which is in the range of 0.75-0.9. Also, the simulated profile of the surge tip was comparable to the empirical equations refereed in Ramsden (1996). The model is applied to the study the maximum force and the run-up height on inclined walls with different inclinations. The results indicate that the maximum force and the run-up height on the wall increase with the increment of wall inclination. Comparison of numerical results with analytical solutions derived from shallow water equations clearly shows the breakdown of shallow water assumption during the impact. In addition to these results, the numerical simulation yields the complete velocity and pressure ?elds which may be used to design structures located in the path of a dam

  8. Forecasting of Storm Surge Floods Using ADCIRC and Optimized DEMs

    NASA Technical Reports Server (NTRS)

    Valenti, Elizabeth; Fitzpatrick, Patrick

    2005-01-01

    Increasing the accuracy of storm surge flood forecasts is essential for improving preparedness for hurricanes and other severe storms and, in particular, for optimizing evacuation scenarios. An interactive database, developed by WorldWinds, Inc., contains atlases of storm surge flood levels for the Louisiana/Mississippi gulf coast region. These atlases were developed to improve forecasting of flooding along the coastline and estuaries and in adjacent inland areas. Storm surge heights depend on a complex interaction of several factors, including: storm size, central minimum pressure, forward speed of motion, bottom topography near the point of landfall, astronomical tides, and most importantly, maximum wind speed. The information in the atlases was generated in over 100 computational simulations, partly by use of a parallel-processing version of the ADvanced CIRCulation (ADCIRC) model. ADCIRC is a nonlinear computational model of hydrodynamics, developed by the U.S. Army Corps of Engineers and the US Navy, as a family of two- and three-dimensional finite element based codes. It affords a capability for simulating tidal circulation and storm surge propagation over very large computational domains, while simultaneously providing high-resolution output in areas of complex shoreline and bathymetry. The ADCIRC finite-element grid for this project covered the Gulf of Mexico and contiguous basins, extending into the deep Atlantic Ocean with progressively higher resolution approaching the study area. The advantage of using ADCIRC over other storm surge models, such as SLOSH, is that input conditions can include all or part of wind stress, tides, wave stress, and river discharge, which serve to make the model output more accurate.

  9. Impact of hurricanes storm surges on the groundwater resources

    USGS Publications Warehouse

    Van Biersel, T. P.; Carlson, D.A.; Milner, L.R.

    2007-01-01

    Ocean surges onto coastal lowlands caused by tropical and extra tropical storms, tsunamis, and sea level rise affect all coastal lowlands and present a threat to drinking water resources of many coastal residents. In 2005, two such storms, Hurricanes Katrina and Rita struck the Gulf Coast of the US. Since September 2005, water samples have been collected from water wells impacted by the hurricanes' storm surges along the north shore of Lake Pontchartrain in southeastern Louisiana. The private and public water wells tested were submerged by 0.6-4.5 m of surging saltwater for several hours. The wells' casing and/or the associated plumbing were severely damaged. Water samples were collected to determine if storm surge water inundated the well casing and, if so, its effect on water quality within the shallow aquifers of the Southern Hills Aquifer System. In addition, the samples were used to determine if the impact on water quality may have long-term implication for public health. Laboratory testing for several indicator parameters (Ca/Mg, Cl/Si, chloride, boron, specific conductance and bacteria) indicates that surge water entered water wells' casing and the screened aquifer. Analysis of the groundwater shows a decrease in the Ca/Mg ratio right after the storm and then a return toward pre-Katrina values. Chloride concentrations were elevated right after Katrina and Rita, and then decreased downward toward pre-Katrina values. From September 2005 to June 2006, the wells showed improvement in all the saltwater intrusion indicators. ?? 2007 Springer-Verlag.

  10. Storm surge characteristics and extreme parameters in the Chengshantou sea area

    NASA Astrophysics Data System (ADS)

    Jin, Y. D.; Zhao, X.; Ma, L. N.

    2017-08-01

    Storm surge in the Chengshantou sea area is simulated by the advanced circulation (ADCIRC) model. The Regional Atmospheric Modeling System (RAMS) wind model is used to simulate wind parameters used to be wind force of storm surge model. The comparison results of storm surges show good agreement between simulations and observations. The storm surge is caused by typhoon in summer but extratropical cyclone in winter. By statistical analysis of storm surge in 20 years, it is found that the annual max negative storm surge are all caused by extratropical cyclone while the frequency of annual max positive storm surge caused by tropical cyclone is about 20%. The extreme parameters are estimated by Gumbel distribution. The positive extreme storm surge of 100 year return period is determined as 95 cm and the negative is -124 cm.

  11. A basis function approach for exploring the seasonal and spatial features of storm surge events

    NASA Astrophysics Data System (ADS)

    Wu, Wenyan; Westra, Seth; Leonard, Michael

    2017-07-01

    Storm surge is a significant contributor to flooding in coastal and estuarine regions. To represent the statistical characteristics of storm surge over a climatologically diverse region, we propose the use of basis functions that capture the temporal progression of individual storm surge events. This extends statistical analyses of surge from considering only the peak to a more multifaceted approach that also includes decay rate and duration. Our results show that there is seasonal variation in storm surge along the Australian coastline. During the dominant storm surge seasons, the peak and duration of storm surge events tend to increase simultaneously at a number of locations, with implications for flood damage assessments and evacuation planning. By combining the dynamic and statistical features of storm surge, it is possible to better understand the factors that can lead to flood risk along the coastline, including estuarine areas that are also affected by fluvial floods.

  12. Impacts of Storm Surges on the Hoover Dike of Lake Okeechobee

    NASA Astrophysics Data System (ADS)

    Li, Y.; Teng, Y. C.; Kelly, D.; Zhang, K.

    2016-02-01

    The Coastal and Estuary Storm Tide (CEST) model, is employed to study water level response to hurricane on the Lake Okeechobee and the storm surge impact on the surrounding dike. The comparison of computed and observed storm surges from Hurricanes Jeanne (2004) and Wilma (2005) indicates that the CEST model well replicated storm surges. Strom surges from hypothetical hurricanes, with varies tracks, maximum wind speed, and forward speed together with different still lake water level, were used to examine surge impacts on the dike. The results show that the hurricanes from the west-south-west produce highest storm surges on the lake for the same category hurricanes, while the hurricanes from the north-north-west generate the lowest storm surges. The hurricanes with fast forwarding speed produce higher storm surges than the slow forwarding hurricanes. The results also indicated that overtopping most likely occurs at the southwest and northwest portion of the dike.

  13. Effect of Coupling Wave and Flow Dynamics on Hurricane Surge and Inundation

    DTIC Science & Technology

    2012-01-01

    impacted hurricanes - both by the wind fields as well as by the accompanying surge. Forecasting the extent of the inundation is critical for local...estimate local surge hazards; and in the other, ensemble model runs are used to determine surge values from a set of parameterized storms [Irish et...with the storm surge to create the storm tide. The extent of coastal inundation - flooding of inland surface that is not normally submerged, is

  14. Storm Surges. Teacher Guide and Activity Book. OEAGLS Investigation No. 25.

    ERIC Educational Resources Information Center

    Keir, John; Mayer, Victor J.

    This investigation is designed to help students understand storm surges on Lake Erie. Activity A includes experiments and discussions intended to help students understand what causes storm surges on Lake Erie. Activity B considers how storm surges affect water levels and, in turn, coastal areas. The student booklet contains questions, experiments,…

  15. Rapid Response Measurements of Hurricane Waves and Storm Surge

    NASA Astrophysics Data System (ADS)

    Gravois, U.

    2010-12-01

    Andrew (1992), Katrina (2005), and Ike (2008) are recent examples of extensive damage that resulted from direct hurricane landfall. Some of the worst damages from these hurricanes are caused by wind driven waves and storm surge flooding. The potential for more hurricane disasters like these continues to increase as a result of population growth and real estate development in low elevation coastal regions. Observational measurements of hurricane waves and storm surge play an important role in future mitigation efforts, yet permanent wave buoy moorings and tide stations are more sparse than desired. This research has developed a rapid response method using helicopters to install temporary wave and surge gauges ahead of hurricane landfall. These temporary installations, with target depths from 10-15 m and 1-7 km offshore depending on the local shelf slope, increase the density of measurement points where the worst conditions are expected. The method has progressed to an operational state and has successfully responded to storms Ernesto (2006), Noel (2007), Fay (2008), Gustav (2008), Hanna (2008) and Ike (2008). The temporary gauges are pressure data loggers that measure at 1 Hz continuously for 12 days and are post-processed to extract surge and wave information. For the six storms studied, 45 out of 49 sensors were recovered by boat led scuba diver search teams, with 43 providing useful data for an 88 percent success rate. As part of the 20 sensor Hurricane Gustav response, sensors were also deployed in lakes and bays inLouisiana, east of the Mississippi river delta. Gustav was the largest deployment to date. Generally efforts were scaled back for storms that were not anticipated to be highly destructive. For example, the cumulative total of sensors deployed for Ernesto, Noel, Fay and Hanna was only 20. Measurement locations for Gustav spanned over 800 km of exposed coastline from Louisiana to Florida with sensors in close proximity to landfall near Cocodrie

  16. Numerical Experiments for Storm Surge Inundation in Korean Coastal Area

    NASA Astrophysics Data System (ADS)

    Yoon, J.; Shim, J.; Jun, K.

    2012-12-01

    Sea-level rising due to climate change following the global warming and the increased intensity of typhoon are magnifying inundation hazards up to the unpredictable level, resulting from the typhoon surge in Korea and other coastal states around the world. Typhoon is the most serious natural disaster in Korean coastal area. Many people died by storm surge inundation every year. And typhoon caused a lot of damage to property. Climate changes due to global warming are producing a stronger natural disaster. Coastal zones have been damaged by typhoons and accompanying storm surge. Especially, the most serious loss of life and terrible property damage caused by typhoon Maemi in 2003. The typhoon Maemi invaded Korean Peninsula leaving property loss of $ 4 Billion and killing 131 people. After then, there has been an increased interest in these coastal zone problems. If storm surges coincide with high tides, the loss of life and property damage due to high waters arc even worse. Therefore it is desirable to accurately forecast the amount water level increase. In this study, using a numerical model FVCOM(finite volume coastal circulation model, Chen et al.,2004), storm surge was simulated to examine its fluctuation characteristics for the coastal area behind Masan, Yeosu and Busan city in Korea. In the numerical model, a moving boundary condition(wet-dry treatment) was incorporated to explain wave inundation. To simulate the inundation scenario, the model grids were extended up to the area inside the lowland in application of the digital elevation data(DEM) made by precisely combining the aero-LiDAR survey data and bathymetry data for the 3 demonstration regions of Busan, Masan and Yeosu. Minimum grid of 300 m unstructured triangular mesh applied to calculate the storm surge was adopted as a grid system. And the minimum grid size of 30 m was built near Busan, Masan and Yeosu area which are the fine coastal regions and where the inundation is simulated. Numerically

  17. Analysis on Lightning Surge Propagation in Wind Farm

    NASA Astrophysics Data System (ADS)

    Yasuda, Yoh; Hara, Takehisa; Funabashi, Toshihisa

    Wind power generation is expected to become more important in the future distribution system. Although several prospective reports such as IEC 61400-24 and NREL SR-500-31115 indicate on insulation scheme and grounding design for lightning protection, it still seems that there are not many investigations on the problems. This paper therefore discusses lightning surge analysis using wind farm model with 2 or 10 ideal wind turbines. Changing parameters such as grounding resistance and lightning strike points, several cases were studied. As the result of the analysis using digital simulator ARENE, it is clear that the surge tends to propagate toward the end of a distribution line in a wind farm and there is possibility of insulation accidents at the other wind turbines when lightning attacks a wind turbine.

  18. Use of historical information in extreme storm surges frequency analysis

    NASA Astrophysics Data System (ADS)

    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

  19. Seismic pressure surges in liquid-filled pipelines

    SciTech Connect

    Hatfield, F.J.; Wiggert, D.C. )

    1990-08-01

    Observed damage and analytic studies indicate that earthquakes may cause destructive pressure surges in liquid-filled piping. Most studies have concerned buried piping that could be assumed to move with the ground. However, pressure surges also would be expected in above-ground piping, where they would affect the displacement response and, hence, the amplitude of flexural stress in the piping. Current aseismic design practice is to simplify this effect by treating the contained liquid as incompressible mass. This paper describes a technique for computing pressure and relative displacement that incorporates elasticity of both the piping and the liquid. Seismic responses of an example pipeline are predicted. It was found that assuming the piping to be rigid produced an upper-bound estimate of pressure, but assuming the liquid to be incompressible resulted in underestimating displacement of the piping.

  20. Source of a Prominent Poleward Surge During Solar Cycle 24

    NASA Astrophysics Data System (ADS)

    Yeates, A. R.; Baker, D.; van Driel-Gesztelyi, L.

    2015-11-01

    As an observational case study, we consider the origin of a prominent poleward surge of leading polarity, visible in the magnetic butterfly diagram during Solar Cycle 24. A new technique is developed for assimilating individual regions of strong magnetic flux into a surface-flux transport model. By isolating the contribution of each of these regions, the model shows the surge to originate primarily in a single high-latitude activity group consisting of a bipolar active region present in Carrington Rotations 2104 - 05 (November 2010 - January 2011) and a multipolar active region in Rotations 2107 - 08 (February - April 2011). This group had a strong axial dipole moment opposed to Joy's law. On the other hand, the modelling suggests that the transient influence of this group on the butterfly diagram will not be matched by a large long-term contribution to the polar field because it is located at high latitude. This is in accordance with previous flux-transport models.

  1. Surge Voltages Induced in Secondary Circuits of 275kV Full GIS

    NASA Astrophysics Data System (ADS)

    Hatano, Ryosuke; Ueda, Toshiaki; Nojima, Kenichi; Motoyama, Hideki

    The study of surge voltage levels induced in low voltage control or monitoring circuits by lightning surges is very important for the rational design of those circuits in substations. To investigate the induction levels in those circuits, we carried out full-scale lightning impulse tests in a new 275kV full GIS substation. The obtained data clarified that the induced surge levels are under the testing levels of related standards. We analyzed the surge waveforms in the Potential Transformer (PT) secondary circuit by EMTP. The analysis indicated that induced surge levels are almost decided by the ratio of winding and the overvoltage level in a main circuit.

  2. Pressurizer with a mechanically attached surge nozzle thermal sleeve

    SciTech Connect

    Wepfer, Robert M

    2014-03-25

    A thermal sleeve is mechanically attached to the bore of a surge nozzle of a pressurizer for the primary circuit of a pressurized water reactor steam generating system. The thermal sleeve is attached with a series of keys and slots which maintain the thermal sleeve centered in the nozzle while permitting thermal growth and restricting flow between the sleeve and the interior wall of the nozzle.

  3. Using Adaptive Mesh Refinment to Simulate Storm Surge

    NASA Astrophysics Data System (ADS)

    Mandli, K. T.; Dawson, C.

    2012-12-01

    Coastal hazards related to strong storms such as hurricanes and typhoons are one of the most frequently recurring and wide spread hazards to coastal communities. Storm surges are among the most devastating effects of these storms, and their prediction and mitigation through numerical simulations is of great interest to coastal communities that need to plan for the subsequent rise in sea level during these storms. Unfortunately these simulations require a large amount of resolution in regions of interest to capture relevant effects resulting in a computational cost that may be intractable. This problem is exacerbated in situations where a large number of similar runs is needed such as in design of infrastructure or forecasting with ensembles of probable storms. One solution to address the problem of computational cost is to employ adaptive mesh refinement (AMR) algorithms. AMR functions by decomposing the computational domain into regions which may vary in resolution as time proceeds. Decomposing the domain as the flow evolves makes this class of methods effective at ensuring that computational effort is spent only where it is needed. AMR also allows for placement of computational resolution independent of user interaction and expectation of the dynamics of the flow as well as particular regions of interest such as harbors. The simulation of many different applications have only been made possible by using AMR-type algorithms, which have allowed otherwise impractical simulations to be performed for much less computational expense. Our work involves studying how storm surge simulations can be improved with AMR algorithms. We have implemented relevant storm surge physics in the GeoClaw package and tested how Hurricane Ike's surge into Galveston Bay and up the Houston Ship Channel compares to available tide gauge data. We will also discuss issues dealing with refinement criteria, optimal resolution and refinement ratios, and inundation.

  4. Designers pick surge hoppers over bins for many boilers

    SciTech Connect

    Schwieger, B.

    1980-02-01

    A boiler fuel-feed system is described and the use of live- bottom surge hoppers is preferred over bins with multiple-screw feeders. The need for an even distribution of hog fuel without segregation by size among the various feed chutes to supply the furnace is stressed. The distribution of fuel among the chutes using flight conveyors, swining spouts and vibrating conveyors is described.

  5. Hurricane Surge Stage-Frequency Analysis for Dade County, Florida.

    DTIC Science & Technology

    1980-08-01

    typically taken out to the 300- or 600-ft contour. Offshore from Biscayne Bay , these depths are found only a few miles seaward. The constriction in the cur...S. Army Engineer District, Jacksonville, CE. 1963. "Survey Report on Hurricane Protective Measures for Biscayne Bay , Fla." (Revised), Jacksonville...and Storm Surge Response in the Corpus Christi-Aransas Bay System" prepared for the U. S. Army Coastal Engineering Research Center, CE, and the U. S

  6. Trends in North American tides and storm surge, 1844-present

    NASA Astrophysics Data System (ADS)

    Talke, S. A.

    2016-02-01

    Using hundreds of station-years of archival tide data found in the US National Archives and digitized by students, we investigate the hypothesis that depth and other topographic changes to estuaries and tidal rivers have increased tidal constituent amplitudes and other long-waves such as storm surge and river floods. In the Columbia River Estuary, both numerical models and data suggest that channel deepening has increased the M2 tide by 10% since 1854, and resulted in faster and less dispersive flood waves. In Wilmington (NC), measurements and an idealized model show that the M2 tide has doubled since the 1880s, leading to large increases in the modeled storm surge. Analysis of other archival records from Boston (1847-present), Providence (1872-present), Philadelphia (1901-present), Norfolk (1844-present), Charleston (1850-present) , San Diego (1854-present), and San Francisco (1858-present) suggest that perturbations in harbor tidal properties are the rule, rather than the exception; in particular, comparison with nearby gauges suggests that coastal tides are much less changed over time, as measured for example by trends in overtides. A primary cause is increased channel depth, which has approximately doubled in many locations since the mid-19th century. Since depth is inversely proportional to friction in the linearized shallow water equations, increasing depth (by sea-level rise or channel deepening) has the same effect as decreasing friction. Such changes may help explain observations in New York harbor, where the elevation of the once-in 10 year storm surge has increased by nearly 0.3m since the mid-19th century. Other factors include altered river flow and resonance; for example, both analytical models and measurements suggest that the M2 tide has increased by 3% in Long Island Sound since 1892. To sum up, changes in tides can be used as an indicator of system sensitivity and can help determine whether the risk from extreme events such as storm surge will

  7. Using satellite altimetry and tide gauges for storm surge warning

    NASA Astrophysics Data System (ADS)

    Andersen, O. B.; Cheng, Y.; Deng, X.; Steward, M.; Gharineiat, Z.

    2015-03-01

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

  8. Modeling potential tsunami river surge in Redwood Creek, California

    NASA Astrophysics Data System (ADS)

    Courtney, J. E.; Admire, A. R.; Nicolini, T.; Dengler, L. A.

    2013-12-01

    Significant destruction can be caused by tsunami penetration in estuaries and up river channels. In the 1964 tsunami on the west coast of North America, much of the resulting damage was caused by tsunami river bores penetrating miles inland. A HEC-RAS model is used in this study to look at the likely extent of inundation from both distant and near-field tsunamis in Redwood Creek on the north coast of California. The Redwood Creek drainage basin has been analyzed extensively for riverine flooding, levee stability and sediment transport. The unsteady flow model in HEC-RAS uses an implicit finite difference scheme to approximate solutions to the continuity and momentum equations. Two different scenarios are evaluated in this analysis: 1. tsunami propagation up a dry river channel; 2. tsunami propagation up a partially full river channel. Scenario 1 provides the baseline for propagation behavior without river flow influence. Scenario 2 uses the HEC-RAS model to determine steady state conditions in the channel for different flow rates to establish initial boundary conditions. The tsunami magnitude and flow conditions are altered to determine the effect on tsunami surge propagation. This is achieved by altering the downstream boundary conditions to simulate the influence of a tsunami surge propagation event. A sensitivity analysis is conducted on the model parameters. The study will assist in tsunami hazard modeling and mitigation in areas where tsunami surge propagation is a concern to communities located along rivers.

  9. Population vulnerability to storm surge flooding in coastal Virginia, USA.

    PubMed

    Liu, Hua; Behr, Joshua G; Diaz, Rafael

    2016-07-01

    This study aims to assess the vulnerability of populations to storm surge flooding in 12 coastal localities of Virginia, USA. Population vulnerability is assessed by way of 3 physical factors (elevation, slope, and storm surge category), 3 built-up components (road availability, access to hospitals, and access to shelters), and 3 household conditions (storm preparedness, financial constraints to recovering from severe weather events, and health fragility). Fuzzy analysis is used to generate maps illustrating variation in several types of population vulnerability across the region. When considering physical factors and household conditions, the most vulnerable neighborhoods to sea level rise and storm surge flooding are largely found in urban areas. However, when considering access to critical infrastructure, we find rural residents to be more vulnerable than nonrural residents. These detailed assessments can inform both local and state governments in catastrophic planning. In addition, the methodology may be generalized to assess vulnerability in other coastal corridors and communities. The originality is highlighted by evaluating socioeconomic conditions at refined scale, incorporating a broader range of human perceptions and predispositions, and employing a geoinformatics approach combining physical, built-up, and socioeconomic conditions for population vulnerability assessment. Integr Environ Assess Manag 2016;12:500-509. © 2015 SETAC.

  10. Hypothalamic control of the male neonatal testosterone surge.

    PubMed

    Clarkson, Jenny; Herbison, Allan E

    2016-02-19

    Sex differences in brain neuroanatomy and neurophysiology underpin considerable physiological and behavioural differences between females and males. Sexual differentiation of the brain is regulated by testosterone secreted by the testes predominantly during embryogenesis in humans and the neonatal period in rodents. Despite huge advances in understanding how testosterone, and its metabolite oestradiol, sexually differentiate the brain, little is known about the mechanism that actually generates the male-specific neonatal testosterone surge. This review examines the evidence for the role of the hypothalamus, and particularly the gonadotropin-releasing hormone (GnRH) neurons, in generating the neonatal testosterone surge in rodents and primates. Kisspeptin-GPR54 signalling is well established as a potent and critical regulator of GnRH neuron activity during puberty and adulthood, and we argue here for an equally important role at birth in driving the male-specific neonatal testosterone surge in rodents. The presence of a male-specific population of preoptic area kisspeptin neurons that appear transiently in the perinatal period provide one possible source of kisspeptin drive to neonatal GnRH neurons in the mouse.

  11. New insights in the ongoing surge of the Austfonna icecap

    NASA Astrophysics Data System (ADS)

    Schellenberger, T.; Dunse, T.; Kääb, A.; Hagen, J. O.; Schuler, T.; Reijmer, C.

    2014-12-01

    Basin-3, a major drainage basin of the Austfonna icecap in NE-Svalbard switched to full surge mode in autumn 2012 after a multiannual, stepwise acceleration of its northern branch. A time series of velocity maps from repeat TerraSAR-X acquisitions revealed a maximum speed at the terminus of >18 m d-1 around the turn of the year 2012. The frontal ablation of Basin-3 was estimated to 4.2±1.6 Gt a-1 between April 2012 and May 2013, tripling the total dynamic mass loss from the largest icecap in the Eurasian arctic. Today, TerraSAR-X, Radarsat-2 and GPS data show that the surge is still ongoing. While the speed at the calving front dropped to 10 m d-1 until July 2014, areas further inland continued to accelerate after the climax, and 10 m d-1 were also measured ~20 km inland in summer 2014. This development will be further investigated by exploiting a time series of velocity maps based on Radarsat-2 Fine Beam data starting from July 2014, which will, other than the TerraSAR-X data, cover almost the entire fast flowing part of the basin. By combining both datasets we will extend the estimation of the frontal ablation and related sea-level rise contribution of the Basin-3 surge.

  12. Bayesian modelling of extreme surges on the UK east coast.

    PubMed

    Coles, Stuart; Tawn, Jonathan

    2005-06-15

    The catastrophic surge event of 1953 on the eastern UK and northern European coastlines led to widespread agreement on the necessity of a coordinated response to understand the risk of future oceanographic flood events and, so far as possible, to afford protection against such events. One element of this response was better use of historical data and scientific knowledge in assessing flood risk. The timing of the event also coincided roughly with the birth of extreme value theory as a statistical discipline for measuring risks of extreme events, and over the last 50 years, as techniques have been developed and refined, various attempts have been made to improve the precision of flood risk assessment around the UK coastline. In part, this article provides a review of such developments. Our broader aim, however, is to show how modern statistical modelling techniques, allied with the tools of extreme value theory and knowledge of sea-dynamic physics, can lead to further improvements in flood risk assessment. Our long-term goal is a coherent spatial model that exploits spatial smoothness in the surge process characteristics and we outline the details of such a model. The analysis of the present article, however, is restricted to a site-by-site analysis of high-tide surges. Nonetheless, we argue that the Bayesian methodology adopted for such analysis enables a risk-based interpretation of results that is most natural in this setting, and preferable to inferences that are available from more conventional analyses.

  13. Hypothalamic control of the male neonatal testosterone surge

    PubMed Central

    Clarkson, Jenny; Herbison, Allan E.

    2016-01-01

    Sex differences in brain neuroanatomy and neurophysiology underpin considerable physiological and behavioural differences between females and males. Sexual differentiation of the brain is regulated by testosterone secreted by the testes predominantly during embryogenesis in humans and the neonatal period in rodents. Despite huge advances in understanding how testosterone, and its metabolite oestradiol, sexually differentiate the brain, little is known about the mechanism that actually generates the male-specific neonatal testosterone surge. This review examines the evidence for the role of the hypothalamus, and particularly the gonadotropin-releasing hormone (GnRH) neurons, in generating the neonatal testosterone surge in rodents and primates. Kisspeptin–GPR54 signalling is well established as a potent and critical regulator of GnRH neuron activity during puberty and adulthood, and we argue here for an equally important role at birth in driving the male-specific neonatal testosterone surge in rodents. The presence of a male-specific population of preoptic area kisspeptin neurons that appear transiently in the perinatal period provide one possible source of kisspeptin drive to neonatal GnRH neurons in the mouse. PMID:26833836

  14. Surge characteristics and protection of distribution transformers. Final report

    SciTech Connect

    McMillen, C.J.; Schoendube, C.W.; Kaufmann, G.H.

    1984-01-01

    This report describes the results of an experimental study to determine the causes and prevention of anomalous failures of distribution transformers due to lightning. Utility surveys, literature searches, and the contractor's prior research determined the experiments performed to test the validity of probable causes. Scaled impulse tests on winding insulation and full magnitude tests on representative 95 kV BIL rated transformers were performed. The impulse tests simulated non-standard impulse wave shapes, methods of application, and simultaneous transient loading on new and aged transformers. Similar voltage and current surge tests were performed on typical 10 kV rated silicon carbide element distribution arresters and metal oxide varistor arrester elements. A new transient voltage computer program was utilized to predict the performance of 125 kV BIL transformers under the same type tests. The primary causes of anomalous failures were attributed to lightning surges entering shell type transformers with non-interlaced 240/120 volt coils, via the low voltage terminals; high rate of rise lightning surges impinging on transformers protected by separately mounted arresters; and shell type transformers using solid paper pad high-to-low insulation when tested to demonstrate their effectiveness.

  15. Traumatic asphyxia following stadium crowd surge: stadium factors affecting outcome.

    PubMed

    DeAngeles, D; Schurr, M; Birnbaum, M; Harms, B

    1998-10-01

    Stadium crowd surges frequently occur following major athletic events. A recent crowd surge injured more than 80 persons by trampling and/or crushing. This incident was reviewed to identify injury patterns consistent with crush-related injury. In addition, the incident was reviewed to determine which stadium policy and design factors may have potentiated this event. A recent crowd surge occurred following a college football game. This resulted in 86 people being transported to the University of Wisconsin and other area hospitals. All charts were reviewed to evaluate patient outcomes. The stadium was examined as were security system video tapes to evaluate stadium factors that contributed to this event. Current policies were obtained through the university sports administration. Of 86 patients transported for evaluation of stadium-related injuries, 10 were treated for traumatic asphyxia. Other injuries requiring hospital admission included musculo-skeletal trauma in two patients and one grade II liver injury. Six others were admitted overnight for observation. Several stadium factors were identified that contributed to the event, and appropriate changes in crowd control policies and stadium design were instated to prevent recurrence. This report details the largest single report of traumatic asphyxia second to the England Hillsborough disaster. Several stadium factors were identified that resulted in crush-related injury. Cooperative review and modification of stadium policies and design may prevent such events in the future.

  16. H{α} Surges Aroused by Newly-emerging Satellite Bipolar Magnetic Field

    NASA Astrophysics Data System (ADS)

    Wang, J. F.; Zhou, T. H.; Ji, H. S.

    2013-07-01

    An Hα surge event occurred at AR NOAA 11259 on 2011 July 22. According to the BBSO (Big Bear Solar Observatory) Hα line-center observations, three surges continuously ejected from the same region to the north of the main-sunspot of AR 11259. All of surges ejected along a straight trajectory, and looked like the reversed Eiffel Tower. The first and second surges had the same process. Two bright points firstly appeared to the north of the main-sunspot. After several minutes, a surge appeared between the two bright points, and then rapidly ejected when the two points got most brightness.When the surge reached the maximum height, it disappeared quickly. However, the third surge appeared without bright points, and its height was only half of the others. Compared with SDO/HMI (Solar Dynamics Observatory/Helioseismic and Magnetic Imager) line-of-sight magnetogram, more than one hour before the first surge appeared, a satellite bipolar magnetic field emerged from the surge-ejection region. The newly-emerging positive magnetic flux showed a distinct decrease several minutes earlier than the ejection of the surges. We assumed that the surges was associated with the reconnection between the newly-emerging bipolar magnetic field and the existing (sunspot) magnetic field.

  17. Can we use crevasse fill ridges for identifying undocumented surge behavior in Svalbard?

    NASA Astrophysics Data System (ADS)

    Farnsworth, W. R.; Ingolfsson, O.; Schomacker, A.; Retelle, M.

    2015-12-01

    Documenting glaciers that exhibit surge type behavior is crucial, especially as we attempt to use evidence of ice front fluctuations for reconstructing past climate oscillations. Controversy exists regarding the relationship between surge activity and climatic processes such as mass balance. This project identifies undocumented surge type glaciers in Svalbard based on the presence of crevasse fill ridges (CFRs) visible in glacier forelands. Although it is acknowledged that many Svalbard outlet glaciers surge, estimates vary greatly as to the actual number of surge- type glaciers in Svalbard, and their distribution pattern is not well understood. A detailed survey of recent (2008-2011), high resolution imagery from Toposvalbard, provided by the Norwegian Polar Institute, allowed for a rapid analysis of Svalbard outlet glaciers. Using CFRs as indicators of surge behavior has almost doubled the amount of potential surge-type glaciers in central Spitsbergen. This method also highlights numerous other glaciers of potential surge type behavior throughout the archipelago. Limits to the CFR identification method are discussed. Additionally as the forelands of previously reported surge type glaciers were analyzed for CFRs, it was evident that the surge indicators were only present in approximately half of the forelands. Numerous factors control the formation and preservation of CFRs including; glacier size, bedrock lithology, subglacial sediments and clast size as well as glacial fluvial run-off. This poster focuses on the controlling factors for CFR formation and preservation as well as other potential methods for effectively identifying surge behavior.

  18. A 300 Year Surge History of the Drangajökull Ice Cap, Northwest Iceland: Surge Frequency and Little Ice Age Maximum

    NASA Astrophysics Data System (ADS)

    Brynjolfsson, S.; Schomacker, A.; Ingolfsson, O.; Gudmundsdottir, E. R.

    2014-12-01

    Over the last 300 years, each of the three surge-type outlet glaciers of the Drangajökull ice cap in north-west Iceland has surged 2-4 times. There is valuable historical information available on the surge frequencies since the Little Ice Age (LIA) maximum because of the proximity of the surging outlets, Reykjarfjarðarjökull, Leirufjarðarjökull and Kaldalónsjökull to farms and pastures. We have reconstructed the surge history of the Drangajökull ice cap, based on geomorphological mapping, sedimentary studies and review of historical records. Geomorphological mapping of the glacier forefields revealed twice as many end-moraines than previously recognized. This indicates a higher surge frequency than previously perceived. A clear relationship between the surge frequency and climate cannot be established, however, surges were more frequent during the 19th century and the earliest 20th century compared to the cool 18th century and the warmer late part of the 20th century. We have estimated the magnitude of the LIA maximum surge events by reconstruction of Digital Elevation Models (DEMs) that can be compared with modern DEMs. As reference points for the digital elevation modelling we used the recently mapped lateral moraines and historical information on the exposure timing of nunataks. During the LIA maximum surge events the outlet glaciers extended 3-3.5 km further down-valley than at present. Their ice volumes were at least 2-2.5 km3 greater than after their most recent surges in the beginning of the 21st century.

  19. Influence of dynorphin on estradiol- and cervical stimulation-induced prolactin surges in ovariectomized rats.

    PubMed

    Stathopoulos, Andrea M; Helena, Cleyde V; Cristancho-Gordo, Ruth; Gonzalez-Iglesias, Arturo E; Bertram, Richard

    2016-08-01

    Prolactin is an anterior pituitary hormone necessary for fertility, pregnancy maintenance, lactation, and aspects of maternal behavior. In rodents, there is a surge of prolactin on the afternoon of proestrus, and a semi-circadian pattern of prolactin surges during early pregnancy, with a diurnal and nocturnal surge every day. Both of these patterns can be replicated in ovariectomized rats. A prior study demonstrated that central antagonism of κ-opioid receptors, the target of dynorphin, largely abolished the nocturnal prolactin surge in pregnant rats. We build on this to determine whether dynorphin, perhaps from the arcuate population that co-express kisspeptin, neurokinin B, and dynorphin (KNDy neurons), also contributes to the estradiol- or cervical stimulation-induced surges in ovariectomized rats. Ovariectomized rats were treated with either estradiol or cervical stimulation to induce prolactin surge(s). Blood samples were taken around the expected surge time to determine the effect of either acute κ-opioid receptor antagonism or previous chemical ablation of the KNDy population on prolactin levels. Dynorphin antagonism does significantly disrupt the nocturnal prolactin surge, but it does not contribute to the estradiol-induced surge. Chemical ablation of KNDy neurons had opposite effects; ablation of 40 % of the KNDy neurons had no impact on the nocturnal prolactin surge, while a somewhat larger ablation significantly reduced the size of the estradiol-induced surge. We conclude that dynorphin is likely a controlling factor for the nocturnal surge induced by cervical stimulation, and that other KNDy neuron products must play a role in the estradiol-induced surge.

  20. Reliability Effects of Surge Current Testing of Solid Tantalum Capacitors

    NASA Technical Reports Server (NTRS)

    Teverovsky, Alexander

    2007-01-01

    Solid tantalum capacitors are widely used in space applications to filter low-frequency ripple currents in power supply circuits and stabilize DC voltages in the system. Tantalum capacitors manufactured per military specifications (MIL-PRF-55365) are established reliability components and have less than 0.001% of failures per 1000 hours (the failure rate is less than 10 FIT) for grades D or S, thus positioning these parts among electronic components with the highest reliability characteristics. Still, failures of tantalum capacitors do happen and when it occurs it might have catastrophic consequences for the system. This is due to a short-circuit failure mode, which might be damaging to a power supply, and also to the capability of tantalum capacitors with manganese cathodes to self-ignite when a failure occurs in low-impedance applications. During such a failure, a substantial amount of energy is released by exothermic reaction of the tantalum pellet with oxygen generated by the overheated manganese oxide cathode, resulting not only in destruction of the part, but also in damage of the board and surrounding components. A specific feature of tantalum capacitors, compared to ceramic parts, is a relatively large value of capacitance, which in contemporary low-size chip capacitors reaches dozens and hundreds of microfarads. This might result in so-called surge current or turn-on failures in the parts when the board is first powered up. Such a failure, which is considered as the most prevalent type of failures in tantalum capacitors [I], is due to fast changes of the voltage in the circuit, dV/dt, producing high surge current spikes, I(sub sp) = Cx(dV/dt), when current in the circuit is unrestricted. These spikes can reach hundreds of amperes and cause catastrophic failures in the system. The mechanism of surge current failures has not been understood completely yet, and different hypotheses were discussed in relevant literature. These include a sustained scintillation

  1. Surges of outlet glaciers from the Drangajökull ice cap, northwest Iceland

    NASA Astrophysics Data System (ADS)

    Brynjólfsson, Skafti; Schomacker, Anders; Korsgaard, Niels J.; Ingólfsson, Ólafur

    2016-09-01

    Surface elevation and volume changes of the Drangajökull surge-type glaciers, Reykjarfjarðarjökull and Leirufjarðarjökull, were studied by comparing digital elevation models that pre-date and post-date their most recent surges. Annual glacier-frontal measurements were used to estimate average ice velocities during the last surge of the glaciers. The observations show a distinct ice discharge, most of which was from the upper reservoir areas, down to the receiving areas during the surges. The surface draw-down in the reservoir areas was usually 10-30 m during the surges, while the thickening of the receiving areas was significantly more variable, on the order of 10-120 m. Despite a negative geodetic net mass balance derived from the digital elevation models, the reservoir areas have been gaining mass since the surge terminations. This surface thickening along with considerable ablation of the receiving areas will most likely return the glacier surface profiles to the pre-surge stage. Our results indicate that (a) greatest surface thinning in the upper reservoir areas of Drangajökull rather than proximal to the equilibrium line during Vatnajökull surges and (b) development of Drangajökull surges that resembles Svalbard surge-type glaciers rather than Vatnajökull surge-type glaciers. The contrasting surge characteristics could be explained by differences in glacier geometry, topography and substratum of the Drangajökull and Vatnajökull surge-type glaciers.

  2. Versatility of Capsular Flaps in the Salvage of Exposed Breast Implants

    PubMed Central

    Tenna, Stefania; Cagli, Barbara; Pallara, Tiziano; Campa, Stefano; Persichetti, Paolo

    2015-01-01

    Summary: Breast implant exposure due to poor tissue coverage or previous irradiation represents a surgical challenge both in the reconstructive and aesthetic plastic surgery practice. In case of implant extrusion or incipient exposure, the commonly suggested strategies, such as targeted antibiotic therapy, drainage and lavage of the cavity, fistulectomy, and primary closure, may be ineffective leading the surgeon to an unwanted implant removal or to adopt more invasive flap coverage procedures. Breast implant capsule, in its physiological clinical behavior, can be considered as a new reliable source of tissue, which can be used in a wide range of clinical situations. In our hands, capsular flaps proved to be a versatile solution not only to treat breast contour deformities or inframammary fold malpositions but also to salvage exposed breast implants. In this scenario, the use of more invasive surgical techniques can be avoided or simply saved and delayed for future recurrences.(Plast Reconstr Surg Glob Open 2015;3:e340; doi:10.1097/GOX.0000000000000307; Published online 30 March 2015.) PMID:26034647

  3. Versatility of capsular flaps in the salvage of exposed breast implants.

    PubMed

    Brunetti, Beniamino; Tenna, Stefania; Cagli, Barbara; Pallara, Tiziano; Campa, Stefano; Persichetti, Paolo

    2015-03-01

    Breast implant exposure due to poor tissue coverage or previous irradiation represents a surgical challenge both in the reconstructive and aesthetic plastic surgery practice. In case of implant extrusion or incipient exposure, the commonly suggested strategies, such as targeted antibiotic therapy, drainage and lavage of the cavity, fistulectomy, and primary closure, may be ineffective leading the surgeon to an unwanted implant removal or to adopt more invasive flap coverage procedures. Breast implant capsule, in its physiological clinical behavior, can be considered as a new reliable source of tissue, which can be used in a wide range of clinical situations. In our hands, capsular flaps proved to be a versatile solution not only to treat breast contour deformities or inframammary fold malpositions but also to salvage exposed breast implants. In this scenario, the use of more invasive surgical techniques can be avoided or simply saved and delayed for future recurrences.(Plast Reconstr Surg Glob Open 2015;3:e340; doi:10.1097/GOX.0000000000000307; Published online 30 March 2015.).

  4. A Probabilistic Forecasting of Hurricane Induced Storm Surge

    NASA Astrophysics Data System (ADS)

    Appendini, C. M.; Meza, R.; Pedrozo-Acuña, A.

    2014-12-01

    Tropical cyclones (TCs) are a hazard to life and property and a prominent element of the global climate system, thus understanding and predicting their intensity, frequency and possible impacts is of paramount importance to the society. In coastal cities, the determination of the levels of defense against flooding is based on the best estimate of the probability of the hurricane induced storm surge. This certainly involves estimating the probability that a hurricane will pass within some given radius of the point in question, yet there are too few such events in the historical record to infer robust probabilities from the data alone, casting at least some doubt on the historical estimates. Recent research efforts have indicated that one partial solution to this problem is to generate a very large number of synthetic hurricanes, whose most important statistical properties conform to those of historical events. This work presents a cascade modelling approach for the prediction of storm surges in Mexico. The approach involves the numerical simulations of wind, waves and hydrodynamics induced by 3100 synthetic hurricane tracks, in comparison to that determined from the historical events. For this, wind fields are used as forcing in a third generation wave model and a 2D hydrodynamic model, enabling the characterization of hurricane conditions from the synthetic events. For several coastal locations on Mexico, we present a comparison of the estimates with this approach against those directly derived from historical hurricane data. The results suggest that such modelling approach opens the door towards a robust dynamical forecast of TC induced storm surges.

  5. Hybrid vs Adaptive Ensemble Kalman Filtering for Storm Surge Forecasting

    NASA Astrophysics Data System (ADS)

    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.

  6. Operational Prediction of Hurricane Induced Coastal Surge and Inundation

    NASA Astrophysics Data System (ADS)

    Veeramony, J.; Penko, A.; Van Ormondt, M.

    2016-02-01

    As a result of global climate change and sea-level rise, coastal regions areincreasingly vulnerable to wind-driven surge and inundation. Accurate andtimely forecasts of coastal inundation is necessary to assist in emergencyplanning and humanitarian assistance to minimize adverse impact to affectedareas. The US Navy has hitherto used PC-Tides (Posey et al. 2008) foroperational predictions of coastal surge and inundation due to extreme tropicalsystems and the Delft3D modeling suite (Stelling, 1996) for nearshorecirculation when inundation is not the primary concern. PC-Tides does notinclude waves or other global ocean circulation and is also limited to amaximum resolution of approximately 1km, which is insufficient for inundationpredictions (Hope et al. 2013). While the omission of the global oceancirculation is likely to have minor impact on the surge and inundation levels,the omission of waves has a significant effect on the water levels (Hope et al.2013). We will present the details of setting up the Delft3D system for predictingsurge and inundation due to tropical cyclones. The system comprises of thecoupled Delft3D-FLOW and Delft3D-WAVE components along with meteorologicalforcing derived using the combination of forecasts and available best trackinformation for a particular storm system. The validation of the system will bepresented using Hurricane Ike as the example case. Hurricane Ike provides theperfect base test to determine how well the system works because of the largesurge produced along the Louisiana-Texas coast, the large fore-runner surgethat tests the models physics and the large amount of data collected. We willfocus on the system response to various model inputs such as bathymetryresolution and accuracy, changes in sea level and the impact of waves.

  7. Active stabilization to prevent surge in centrifugal compression systems

    NASA Technical Reports Server (NTRS)

    Epstein, Alan H.; Greitzer, Edward M.; Simon, Jon S.; Valavani, Lena

    1993-01-01

    This report documents an experimental and analytical study of the active stabilization of surge in a centrifugal engine. The aims of the research were to extend the operating range of a compressor as far as possible and to establish the theoretical framework for the active stabilization of surge from both an aerodynamic stability and a control theoretic perspective. In particular, much attention was paid to understanding the physical limitations of active stabilization and how they are influenced by control system design parameters. Previously developed linear models of actively stabilized compressors were extended to include such nonlinear phenomena as bounded actuation, bandwidth limits, and robustness criteria. This model was then used to systematically quantify the influence of sensor-actuator selection on system performance. Five different actuation schemes were considered along with four different sensors. Sensor-actuator choice was shown to have a profound effect on the performance of the stabilized compressor. The optimum choice was not unique, but rather shown to be a strong function of some of the non-dimensional parameters which characterize the compression system dynamics. Specifically, the utility of the concepts were shown to depend on the system compliance to inertia ratio ('B' parameter) and the local slope of the compressor speedline. In general, the most effective arrangements are ones in which the actuator is most closely coupled to the compressor, such as a close-coupled bleed valve inlet jet, rather than elsewhere in the flow train, such as a fuel flow modulator. The analytical model was used to explore the influence of control system bandwidth on control effectiveness. The relevant reference frequency was shown to be the compression system's Helmholtz frequency rather than the surge frequency. The analysis shows that control bandwidths of three to ten times the Helmholtz frequency are required for larger increases in the compressor flow range

  8. Cyclic steps due to the surge-type turbidity currents in flume experiments: effect of surge duration on the topography of steps

    NASA Astrophysics Data System (ADS)

    Yokokawa, Miwa; Yamano, Junpei; Miyai, Masatomo; Hughes Clarke, John; Izumi, Norihiro

    2017-04-01

    Field observations of turbidity currents and seabed topography on the Squamish delta in British Columbia, Canada revealed that cyclic steps formed by the surge-type turbidity currents (e.g., Hughes Clarke et al., 2014). The high-density portion of the flow, which affects the sea floor morphology, lasted only 30-60 seconds. We are doing flume experiments aiming to investigate the relationship between the condition of surges and topography of resultant steps. In this presentation, we are going to discuss about the effect of surge duration on the topography of steps. The experiments have been performed at Osaka Institute of Technology. A flume, which is 7.0 m long, 0.3 m deep and 2 cm wide, was suspended in a larger tank, which is 7.6 m long, 1.2 m deep and 0.3 m wide, filled with water. The inner flume tilted at 7 degrees. As a source of turbidity currents, mixture of salt water (1.17 g/cm^3) and plastic particles (1.3 g/cm^3, 0.1-0.18 mm in diameter) was prepared. The concentration of the sediments was 6.1 weight % (5.5 volume %) in the head tank. This mixture of salt water and plastic particles poured into the upstream end of the inner flume from head tank for 3 seconds or 7 seconds. 140 surges were made respectively. Discharge of the currents were fluctuated but range from 306 to 870 mL for 3s-surge, and from 1134 to 2030 mL for 7s-surge. As a result, five or six steps were formed respectively. At the case of 3s-surge, steps located at upstream portion of the flume moved vigorously toward upstream direction, whereas steps at downstream portion of the flume moved toward upstream direction at the case of 7s-surge. The wavelengths and wave heights of the steps by 3s-surge are larger than those of 7s-surge at the upstream portion of the flume, but the size of steps of 3s-surge are smaller than those of 7s-surge at the downstream portion of the flume. In this condition of slope and concentration, the longer surge duration, i.e. larger discharge of the current

  9. Vulnerability of Coastal Communities from Storm Surge and Flood Disasters

    PubMed Central

    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

  10. Critical Resources for Hospital Surge Capacity: An Expert Consensus Panel

    PubMed Central

    Bayram, Jamil D.; Sauer, Lauren M.; Catlett, Christina; Levin, Scott; Cole, Gai; Kirsch, Thomas D.; Toerper, Matthew; Kelen, Gabor

    2013-01-01

    Background: Hospital surge capacity (HSC) is dependent on the ability to increase or conserve resources. The hospital surge model put forth by the Agency for Healthcare Research and Quality (AHRQ) estimates the resources needed by hospitals to treat casualties resulting from 13 national planning scenarios. However, emergency planners need to know which hospital resource are most critical in order to develop a more accurate plan for HSC in the event of a disaster. Objective: To identify critical hospital resources required in four specific catastrophic scenarios; namely, pandemic influenza, radiation, explosive, and nerve gas. Methods: We convened an expert consensus panel comprised of 23 participants representing health providers (i.e., nurses and physicians), administrators, emergency planners, and specialists. Four disaster scenarios were examined by the panel. Participants were divided into 4 groups of five or six members, each of which were assigned two of four scenarios. They were asked to consider 132 hospital patient care resources- extracted from the AHRQ's hospital surge model- in order to identify the ones that would be critical in their opinion to patient care. The definition for a critical hospital resource was the following: absence of the resource is likely to have a major impact on patient outcomes, i.e., high likelihood of untoward event, possibly death. For items with any disagreement in ranking, we conducted a facilitated discussion (modified Delphi technique) until consensus was reached, which was defined as more than 50% agreement. Intraclass Correlation Coefficients (ICC) were calculated for each scenario, and across all scenarios as a measure of participant agreement on critical resources. For the critical resources common to all scenarios, Kruskal-Wallis test was performed to measure the distribution of scores across all scenarios. Results: Of the 132 hospital resources, 25 were considered critical for all four scenarios by more than 50% of

  11. Surge Nozzle NDE Specimen Mechanical Stress Improvement Analysis

    SciTech Connect

    Fredette, Lee F.

    2011-07-14

    The purpose of this project was to perform a finite element analysis of a pressurized water reactor pressurizer surge nozzle mock-up to predict both the weld residual stresses created in its construction and the final stress state after the application of the Mechanical Stress Improvement Process (MSIP). Strain gages were applied to the inner diameter of the mock-up to record strain changes during the MSIP. These strain readings were used in an attempt to calculate the final stress state of the mock-up as well.

  12. Probabilistic modelling of sea surges in coastal urban areas

    NASA Astrophysics Data System (ADS)

    Georgiadis, Stylianos; Jomo Danielsen Sørup, Hjalte; Arnbjerg-Nielsen, Karsten; Nielsen, Bo Friis

    2016-04-01

    Urban floods are a major issue for coastal cities with severe impacts on economy, society and environment. A main cause for floods are sea surges stemming from extreme weather conditions. In the context of urban flooding, certain standards have to be met by critical infrastructures in order to protect them from floods. These standards can be so strict that no empirical data is available. For instance, protection plans for sub-surface railways against floods are established with 10,000 years return levels. Furthermore, the long technical lifetime of such infrastructures is a critical issue that should be considered, along with the associated climate change effects in this lifetime. We present a case study of Copenhagen where the metro system is being expanded at present with several stations close to the sea. The current critical sea levels for the metro have never been exceeded and Copenhagen has only been severely flooded from pluvial events in the time where measurements have been conducted. However, due to the very high return period that the metro has to be able to withstand and due to the expectations to sea-level rise due to climate change, reliable estimates of the occurrence rate and magnitude of sea surges have to be established as the current protection is expected to be insufficient at some point within the technical lifetime of the metro. The objective of this study is to probabilistically model sea level in Copenhagen as opposed to extrapolating the extreme statistics as is the practice often used. A better understanding and more realistic description of the phenomena leading to sea surges can then be given. The application of hidden Markov models to high-resolution data of sea level for different meteorological stations in and around Copenhagen is an effective tool to address uncertainty. For sea surge studies, the hidden states of the model may reflect the hydrological processes that contribute to coastal floods. Also, the states of the hidden Markov

  13. High Resolution Hurricane Storm Surge and Inundation Modeling (Invited)

    NASA Astrophysics Data System (ADS)

    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

  14. Vulnerability of Coastal Communities from Storm Surge and Flood Disasters.

    PubMed

    Bathi, Jejal Reddy; Das, Himangshu S

    2016-02-19

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  16. Coordinated Ground and Space Measurements of Auroral Surge over South Pole.

    DTIC Science & Technology

    1988-02-01

    3y V. Coordinated Ground and Space Measurements of co an Auroral Surge over South Pole T. J. ROSENBERG and D. L. DETRICK Institute for Physical...Measurements of an Auroral Surge over South Pole 12. PERSONAL AUTHOR(S) Rosenberg, T. J., and DetrickD. L., University of Maryland; Mizera, Paul F., 13a. TYPE...premidnight auroral surge over Amundsen-Scott South Pole station. The set of near-simultaneous measurements provides an excellent opportunity to gain a

  17. Analysis of Compressor Surge in a Military Turbojet Engine: A Case Study

    NASA Astrophysics Data System (ADS)

    Mishra, R. K.; Bhat, R. Raghavendra; Chandel, Sunil

    2017-04-01

    A case of compressor surge with bang noise during takeoff roll is investigated and presented in this paper. Fatigue failure of compressor rotor blades during takeoff is found to disturb the aerodynamics of compressor flow causing the surge. Based on evidences, failure of rotor blades and compressor surge due to over-speed and foreign object debris is ruled out. The paper presents the methodology adopted for the investigation and also suggests remedial measures necessary to prevent such incidents.

  18. Mapping and Visualization of Storm-Surge Dynamics for Hurricane Katrina and Hurricane Rita

    USGS Publications Warehouse

    Gesch, Dean B.

    2009-01-01

    The damages caused by the storm surges from Hurricane Katrina and Hurricane Rita were significant and occurred over broad areas. Storm-surge maps are among the most useful geospatial datasets for hurricane recovery, impact assessments, and mitigation planning for future storms. Surveyed high-water marks were used to generate a maximum storm-surge surface for Hurricane Katrina extending from eastern Louisiana to Mobile Bay, Alabama. The interpolated surface was intersected with high-resolution lidar elevation data covering the study area to produce a highly detailed digital storm-surge inundation map. The storm-surge dataset and related data are available for display and query in a Web-based viewer application. A unique water-level dataset from a network of portable pressure sensors deployed in the days just prior to Hurricane Rita's landfall captured the hurricane's storm surge. The recorded sensor data provided water-level measurements with a very high temporal resolution at surveyed point locations. The resulting dataset was used to generate a time series of storm-surge surfaces that documents the surge dynamics in a new, spatially explicit way. The temporal information contained in the multiple storm-surge surfaces can be visualized in a number of ways to portray how the surge interacted with and was affected by land surface features. Spatially explicit storm-surge products can be useful for a variety of hurricane impact assessments, especially studies of wetland and land changes where knowledge of the extent and magnitude of storm-surge flooding is critical.

  19. An Investigation of Hurricane-Induced Forerunner Surge in the Gulf of Mexico

    DTIC Science & Technology

    1985-09-01

    Waterways Experiment Station Coastal Engineering Research Center Unclassified PO Box 631, Vicksburg, Mississippi 39180-0631 1s5. DECLAS•iFICATION...which can have an amplitude as large as .m) can precede the peak surge by more than 24 hours. It is common practice, in employing coastal surge...starting local coastal models well in advance of the arrival of the hurricane at the "shelf break cannot simulate the forerunner surge since the latter

  20. Alternate Care Sites for the Management of Medical Surge in Disasters

    DTIC Science & Technology

    2013-12-01

    facility unable to respond effectively for hours and even days. A whole community approach to medical surge management organized by a collaborative...facility unable to respond effectively for hours and even days. A whole community approach to medical surge management organized by a collaborative...medical resources. This is especially important during the first hours to days when a local community is managing medical surge or awaiting State

  1. Production of a short-lived filament by a surge. [in solar atmosphere

    NASA Technical Reports Server (NTRS)

    Zirin, H.

    1976-01-01

    An unusual solar event is investigated in which a short-lived cloud, very much like a filament, was formed by ejecta from a large surge. The temporal evolution of this surge is described, and evidence is presented which indicates that the short-lived cloud was a bona fide filament. The energetics of this event and the mass of the surge are estimated from radio and X-ray data obtained at the onset.

  2. The 1982 eruptions of El Chichon volcano, Mexico (3): Physical properties of pyroclastic surges

    NASA Astrophysics Data System (ADS)

    Sigurdsson, H.; Carey, S. N.; Fisher, R. V.

    1987-04-01

    Two major pyroclastic surges generated during the 4 April 1982 eruption of El Chichon devastated an area of 153 km2 with a quasi-radial distribution around the volcano. The hot surge clouds carbonized wood throughout their extent and were too hot to allow accretionary lapilli formation by vapor condensation. Field evidence indicates voidage fraction of 0.99 in the surge cloud with extensive entrainment of air. Thermal calculations indicate that heat content of pyroclasts can heat entrained air and maintain high temperatures in the surge cloud. The dominant bed form of the surge deposits are sand waves shaped in dune forms with vertical form index of 10 20, characterized by stoss-side erosion and lee-side deposition of 1 10 cm reversely graded laminae. A systematic decrease in maximum lithic diameter with distance from source is accompanied by decrease in wavelength and amplitude. Modal analysis indicates fractionation of glass and pumice from the surge cloud relative to crystals, resulting in loss of at least 10% 25% of the cloud mass due to winnowing out of fines during surge emplacement. Greatest fractionation from the -1.0 0.0-∅ grain sizes reflects relatively lower pumice particle density in this range and segregation in the formative stages of the surge cloud. Extensive pumice rounding indicates abrasion during bed-load transport. Flow of pyroclastic debris in the turbulent surge cloud was by combination of bed-load and suspended-load transport. The surges are viewed as expanding pyroclastic gravity flows, which entrain and mix with air during transport. The balance between sedimentation at the base of the surge cloud and expansion due to entrainment of air contributed to low cloud density and internal turbulence, which persisted to the distal edge of the surge zone.

  3. The Effect of Sea Level Rise on Storm Surge Flooding in South Florida

    NASA Astrophysics Data System (ADS)

    Zhang, K.

    2012-12-01

    The coastal and estuarine storm tide model (CEST) was employed to estimate storm surges and associated flood caused by Hurricane Andrew for scenarios of sea level rise (SLR) from 0.15 to 1.05 m with an interval of 0.15 m. The interaction between storm surges and SLR is almost linear at the open Atlantic Ocean outside Biscayne Bay, with slight reduction in peak storm surge heights as sea level rises. The nonlinear interaction between storm surges and SLR is weak in Biscayne Bay, leading to small differences (-0.2-0.2 m) in peak storm surge heights estimated using CEST and the linear superposition methods. Therefore, it is appropriate to estimate elevated storm surges caused by SLR in these areas by adding the SLR magnitude to storm surge heights. However, the magnitude and extent of inundation at the mainland area by Biscayne Bay estimated by numerical simulations are, respectively, 16-30% and 22-24% larger on average than those generated by the linear superposition of storm surges and SLR, indicating a strong nonlinear interaction between storm surges and SLR. The population and property affected by the storm surge inundation estimated by numerical simulations differ up to 50-140% from that estimated by the linear superposition methods. Therefore, it is inappropriate to estimate the exacerbated magnitude and extent of storm surge flooding by SLR and affected population and property using the linear superpostion methods. The strong nonlinear interaction between surge flooding and SLR at a specific location occurs at the initial stage of SLR when the water depth under an elevated sea level is less than 0.7 m, while the interaction becomes linear as the depth exceeds 0.7 m.

  4. High amplitude surging and plunging motions at low Reynolds number

    NASA Astrophysics Data System (ADS)

    Choi, Jeesoon; Colonius, Tim; Williams, David; Caltech Collaboration; IIT Collaboration

    2014-11-01

    Aerodynamic forces and flow structures associated with high amplitude oscillations of an airfoil in the streamwise (surging) and transverse (plunging) direction are investigated in two-dimensional simulations at low Reynolds number (Re = 102 ~ 103). While the unsteady aerodynamic forces for low-amplitude motions were mainly affected by the leading-edge vortex (LEV) acting in- or out-of phase with the quasi-component of velocity, large-amplitude motions involve complex vortex interactions of LEVs and trailing-edge vortices (TEVs) with the moving body. For high-amplitude surging, the TEV, instead of the LEV, induces low-pressure regions above the airfoil during the retreating portion of the cycle near the reduced frequency, k = 0.5, and enhances the time-average forces. The time required for the LEV to convect along the chord becomes an intrinsic time scale, and for plunging motions, there is a sudden change of flow structure when the period of the motion is not long enough for the LEV to convect through the whole chord.

  5. Blunting post-meal glucose surges in people with diabetes

    PubMed Central

    Chacko, Elsamma

    2016-01-01

    Worldwide, the morbidity and mortality associated with non-communicable diseases have been climbing steadily - with costs aggressively keeping pace. This letter highlights a decidedly low-cost way to address the challenges posed by diabetes. High levels of postprandial blood glucose are disproportionately linked to much of the microvascular damage which, in the end, leads to macrovascular complications and organ failures. Systematically controlling post-meal glucose surges is a critical element of overall glycemic management in diabetes. Diet, exercise and medications form a triad of variables that individuals engaged in diabetes self-management may manipulate to achieve their targeted glucose levels. As a rule, diabetes patients in developing countries as well as those living in the pockets of poverty in the western world cannot afford special diets, medications, glucometers and supplies, lab tests and office visits. Exercise is the one option that is readily accessible to all. Decades of research in laboratory settings, viewed holistically, have established that light to moderate aerobic exercise for up to 60 min starting 30 min after the first bite into a meal can blunt the ensuing glucose surge effectively. Moderate resistance exercise, moderate endurance exercise or a combination of the two, practiced post-meal has also been found to improve many cardio-metabolic markers: Glucose, high density lipoprotein, triglycerides, and markers of oxidative stress. On the other hand, pre-breakfast exercise and high-intensity exercise in general have been decidedly counterproductive. PMID:27326346

  6. Modelling a storm surge event in Liverpool Bay with FVCOM.

    NASA Astrophysics Data System (ADS)

    Hall, P.

    2012-04-01

    A model of the Irish Sea/Liverpool Bay area has been developed using the finite volume, unstructured mesh code FVCOM. The model has been run with meteorological forcing to simulate the storm surge event of January 2007. This event has previously been modelled with the POLCOMS code, the results of which were used for a comparison of accuracy and computational efficiency of the two approaches. The wind speed (and hence wind stress) together with atmospheric pressure have been applied to the model as surface boundary conditions for a period of a few days to allow the model to settle down, and then the results for the peak of the storm on January 18th 2007 have been analysed to give metrics for the accuracy of the sea surface elevation that is predicted against measurements taken at Hilbre Island, near the mouth of the River Dee in Liverpool Bay. It was found that by changing the wind stress formulation within the FVCOM code a significant improvement in the accuracy of the model results could be obtained for the period of this surge event.

  7. Facilitating Adaptation to Changing Storm Surge Patterns in Western Alaska.

    NASA Astrophysics Data System (ADS)

    Murphy, K. A.; Holman, A.; Reynolds, J.

    2014-12-01

    Coastal regions of North America are already experiencing the effects of climate change and the consequences of new storm patterns and sea level rise. These climate change effects are even more pronounced in western Alaska where the loss of sea ice in early winter and spring are exposing the coast to powerful winter storms that are visibly altering the landscape, putting coastal communities at risk, and are likely impacting important coastal wildlife habitat in ways we don't yet understand. The Western Alaska Landscape Conservation Cooperative has funded a suite of projects to improve the information available to assist managers and communities to adapt changes in coastal storms and their impacts. Projects range from modeling tide, wave and storm surge patters, to ShoreZone and NHD mapping, to bathymetry mapping, community vulnerability assessments and risks to important wildlife habitat. This group of diverse projects has helped stimulate momentum among partners which will lead to better tools for communities to respond to dangerous storms. For example, the State of Alaska and NOAA are working together to compile a series of community-scale maps that utilize best-available datasets to streamline communication about forecasted storm surges, local elevations and potentially impacted infrastructure during storm events that may lead to coastal flooding.

  8. Development of a nonfragmenting distribution surge arrester. Final report

    SciTech Connect

    Koch, R.E.

    1984-08-01

    This report describes the investigation and testing carried out in the development of a nonfragmenting distribution surge arrester. It is commonly assumed that pressure buildup in a failing surge arrester will cause the porcelain to burst unless the pressure is rapidly relieved. Even after pressure relief, however, the porcelain can shatter from the thermal shock produced by the internal arc. There is little published information on the sequence of events during failure and the relative importance of pressure and thermal stress. A prerequisite for the design of a nonfragmenting arrester is a thorough knowledge of the failure mechanism. Extensive testing was performed to determine the contribution of both pressure and heat to porcelain breakage. This research demonstrated the importance of thermal shock and led to the design of an ablative thermal shield for the porcelain housing. This was combined with pressure relief provided by end-cap venting and a retaining system to prevent ejection of internal parts. The final result was the design and production of nonfragmenting distribution arresters rated 9 kV through 27 kV.

  9. New technology and tool prepared for communication against storm surges.

    NASA Astrophysics Data System (ADS)

    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.

  10. Avoiding compressor surge during emergency shutdown hybridturbine systems

    SciTech Connect

    Pezzini, Paolo; Tucker, David; Traverso, Alberto

    2013-01-01

    A new emergency shutdown procedure for a direct-fired fuel cell turbine hybrid power system was evaluated using a hardware-based simulation of an integrated gasifier/fuel cell/turbine hybrid cycle (IGFC), implemented through the Hybrid Performance (Hyper) project at the National Energy Technology Laboratory, U.S. Department of Energy (NETL). The Hyper facility is designed to explore dynamic operation of hybrid systems and quantitatively characterize such transient behavior. It is possible to model, test, and evaluate the effects of different parameters on the design and operation of a gasifier/fuel cell/gas turbine hybrid system and provide a means of quantifying risk mitigation strategies. An open-loop system analysis regarding the dynamic effect of bleed air, cold air bypass, and load bank is presented in order to evaluate the combination of these three main actuators during emergency shutdown. In the previous Hybrid control system architecture, catastrophic compressor failures were observed when the fuel and load bank were cut off during emergency shutdown strategy. Improvements were achieved using a nonlinear fuel valve ramp down when the load bank was not operating. Experiments in load bank operation show compressor surge and stall after emergency shutdown activation. The difficulties in finding an optimal compressor and cathode mass flow for mitigation of surge and stall using these actuators are illustrated.

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

    NASA Astrophysics Data System (ADS)

    Li, K.; Li, G. S.

    2011-07-01

    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.

  12. Relationships between Gulf of California Moisture Surges and Tropical Cyclones in the Eastern Pacific Basin.

    NASA Astrophysics Data System (ADS)

    Higgins, R. W.; Shi, W.

    2005-11-01

    Relationships between Gulf of California moisture surges and tropical cyclones (TCs) in the eastern Pacific basin are examined. Standard surface observations are used to identify gulf surge events at Yuma, Arizona, for a multiyear (July August 1979 2001) period. The surges are related to TCs using National Hurricane Center 6-hourly track data for the eastern Pacific basin. Climate Prediction Center (CPC)- observed daily precipitation analyses and the NCEP Regional Reanalysis are used to examine the relative differences in the precipitation, atmospheric circulation, and moisture fields for several categories of surge events, including those that are directly related to TCs, indirectly related to TCs, and not related to TCs.It is shown that the response to the surge in the southwestern United States and northwestern Mexico is strongly discriminated by the presence or absence of TCs. Surges related to TCs tend to be associated with much stronger and deeper low-level southerly flow, deeper plumes of tropical moisture, and wetter conditions over the core monsoon region than surges that are unrelated to TCs. The response to the surge is also strongly influenced by the proximity of the TC to the Gulf of California (GOC) region. Tropical cyclones that track toward the GOC region exert a stronger, more direct influence on Yuma surges than those that track away from the GOC.

  13. Analysis of Air Force Systems Command's industrial-surge preparedness planning. Master's thesis

    SciTech Connect

    Hunigan, K.A.

    1987-09-01

    As U.S. foreign policy calls for a decrease in Intermediate-range Nuclear Forces in Europe, the U.S. needs to increase its conventional capability in order to maintain vigilant deterrence against the Warsaw Pact forces. The objective of this study was to analyze Air Force Systems Command's industrial-surge preparedness planning and policies and how they are implemented at five major product divisions. This research documents findings and concerns about AFSC's surge preparedness planning and policies, outside influences and relationships, and recommendations for future industrial-base initiatives. Interviews disclosed that industrial surge preparedness planning is a low-priority responsibility. It is not sufficiently funded and rarely addressed at program reviews or milestone decisions. Furthermore, the using commands do not usually offer their surge requirements, but expect AFSC to determine the user's surge requirements for them. A survey indicated that for many programs, surge was not a requirement. However, tactical systems had the greatest share of surge requirements. The survey also indicated that program offices are seldom questioned about surge considerations from their chain of command or their users. Finally, the survey showed that many of the program and project managers have had little to no exposure to surge-preparedness planning through their formal education.

  14. A prediction of storm surge using the artificial neural networks (ANNs) based on a JTWC best track and tide-surge model

    NASA Astrophysics Data System (ADS)

    Park, Junghyun; Yuk, Jin-Hee; An, Jooneun; Joh, Minsu; Kim, Seung-woo

    2017-04-01

    There is huge damage caused by tropical typhoons every year in the South Korea. The storm surge due to landing of typhoon leads to severe flooding and casualty damage in coastal areas. Generally, the storm surge height is defined as the difference between the sea levels observed and predicted considering tide only. This advancing surge combines with the normal tides to create the typhoon storm surge height, which can increase the mean water level from only 1 to more than 2 m by the typhoon characteristics in Korea. To efficiently describe the phenomenon of storm surge in the coastal area, many researchers have used the numerical model of fluid dynamics. However, recently, research activities based on not the numerical model but big data have gotten a lot of attention and the Artificial Neural Networks (ANNs) among these activities have shown powerful pattern classification and pattern recognition capabilities. The ANNs provide an attractive alternative tool for both forecasting researchers and practitioners. In particular, the ANNs have been widely applied to various areas to overcome the nonlinear natural disaster problems. This paper is aimed to propose the application of the ANNs for prediction of the storm surge. Many storm surge data stored for a long time are required to predict storm surge accurately using ANNs. But, because of the lack of storm surge data in the past years, we calculated storm surges due to 53 typhoons which had affected the South Korea from 1978 to 2014 using a finite element tide-surge model (ADvanced CIRCulation Model) and the typhoon information of JTWC (Joint Typhoon Warning Center). Factors such as the six hourly best track data of typhoon, head direction and velocity of typhoons, maximum sustained wind speed, minimum sea level pressure, radius of the last closed isobar, and radius of max winds were used to test the accuracy of the suggested ANNs model. The normalized root mean squared error (RMSE) and correlation coefficient (CC

  15. Surging glaciers and glacial floods in the Upper Indus Basin, Pakistan

    NASA Astrophysics Data System (ADS)

    Reynolds, J. M.

    2003-04-01

    A review of glacial hazards in the Upper Indus Basin, Pakistan, has identified 52 catastrophic floods that have occurred between 1826 and 2000 arising from ice dam failures and glacier lake outburst floods (GLOFs). Surging glaciers have formed large ice dams, where the rapid glacier advances have blocked the adjacent river, and have failed subsequently releasing up to 3 km^3 of water in less than 48 hrs with peak discharges in excess of 40,000 m^3/s. Such catastrophic floods have had run-out distances in excess of 1,200 km and have caused major damage downstream and resulted in many hundreds of fatalities. Since 1980, 75% of recorded glacier-derived floods have originated from GLOFs with only few ice dam failures associated with surging glaciers. Glacier surges have occurred in clusters with individual glaciers going through phases of active surging and then quiescent periods in from 30 to over 100 years. Previous reviews of surging glaciers in the Upper Indus Basin have identified 20 glaciers that have demonstrated surge-type behaviour with the bulk of glacier surges apparently occurring prior to 1933. However, recent satellite imagery (Landsat-5 from 1998/99) has shown that there are a further 16 glaciers that have surged within this region, with several surging simultaneously and in recent years. At least one glacier has been identified on satellite imagery as going through a surge from 1998 to June 2001 when the resultant ice dam failed producing a locally devastating flood. The study has also demonstrated that there is no obvious link between what triggers an individual glacier to surge and climate change. Furthermore, within this seismically very active area, there is no evidence that earthquakes have triggered either surges, collapses of ice dams, or failures of other glacial lake dams, over the period 1927--2001 for which records are available. Surge behaviour within composite glaciers results in highly complex structural effects especially where tributary

  16. INCREASED FLEXIBILITY OF TURBO-COMPRESSORS IN NATURAL GAS TRANSMISSION THROUGH DIRECT SURGE CONTROL

    SciTech Connect

    Robert J. McKee; Danny M. Deffenbaugh

    2004-12-01

    This annual progress report describes the third year's technical progress in a three-year program. This report introduces the benefits of improved surge detection and summarizes what is known about internal flows as surge precursors in centrifugal compressors. Early research results and findings concerning surge in centrifugal compressors and possible precursors to surge are presented. Laboratory test results in modern compressors with 3D impellers are described in detail and used to show the changes in internal flow patterns that occur as a compressor approaches surge. It was found that older compressors with recessed impeller blading (2D geometry) do not have the same accessible flow patterns. The laboratory test results indicate a large increase in potential operating range for modern compressors. This annual report also presents results from the field testing conducted during the course of this third year. The field test results showed similar changes in the surge probe strain signals and the same type, although of less magnitude, of indication that the compressor is approaching surge. An algorithm for identifying the nearness of surge has been proposed and evaluated with the available data. This project is co-funded by the Gas Machinery Research Council (GMRC) and by Siemens Energy and Automation (Siemens). The results of the project include a step-by-step process for design, sizing, and installation of surge detection probes and for implementation of the direct surge control in centrifugal compressor controllers. This work is considered a step towards the successful implementation of direct surge control for improved flexibility and efficiency in natural gas transmission compressors.

  17. A review of tropical cyclone-generated storm surges: Global data sources, observations, and impacts

    NASA Astrophysics Data System (ADS)

    Needham, Hal F.; Keim, Barry D.; Sathiaraj, David

    2015-06-01

    Tropical cyclone-generated storm surges are among the world's most deadly and destructive natural hazards. This paper provides the first comprehensive global review of tropical storm surge data sources, observations, and impacts while archiving data in SURGEDAT, a global database. Available literature has provided data for more than 700 surge events since 1880, the majority of which are found in the western North Atlantic (WNA), followed by Australia/Oceania, the western North Pacific (WNP), and the northern Indian Ocean (NIO). The Bay of Bengal (BOB) in the NIO consistently observes the world's highest surges, as this subbasin averages five surges ≥5 m per decade and has observed credible storm tide levels reaching 13.7 m. The WNP observes the highest rate of low-magnitude surges, as the coast of China averages 54 surges ≥1 m per decade, and rates are likely higher in the Philippines. The U.S. Gulf Coast observes the second highest frequency of both high-magnitude (≥5 m) and low-magnitude (≥1 m) surges. The BOB observes the most catastrophic surge impacts, as 59% of global tropical cyclones that have killed at least 5000 people occurred in this basin. The six deadliest cyclones in this region have each killed at least 140,000 people, and two events have killed 300,000. Storm surge impacts transportation, agriculture, and energy sectors in the WNA. Oceania experiences long-term impacts, including contamination of fresh water and loss of food supplies, although the highest surges in this region are lower than most other basins.

  18. The "Ram Effect": A "Non-Classical" Mechanism for Inducing LH Surges in Sheep.

    PubMed

    Fabre-Nys, Claude; Chanvallon, Audrey; Dupont, Joëlle; Lardic, Lionel; Lomet, Didier; Martinet, Stéphanie; Scaramuzzi, Rex J

    2016-01-01

    During spring sheep do not normally ovulate but exposure to a ram can induce ovulation. In some ewes an LH surge is induced immediately after exposure to a ram thus raising questions about the control of this precocious LH surge. Our first aim was to determine the plasma concentrations of oestradiol (E2) E2 in anoestrous ewes before and after the "ram effect" in ewes that had a "precocious" LH surge (starting within 6 hours), a "normal" surge (between 6 and 28h) and "late» surge (not detected by 56h). In another experiment we tested if a small increase in circulating E2 could induce an LH surge in anoestrus ewes. The concentration of E2 significantly was not different at the time of ram introduction among ewes with the three types of LH surge. "Precocious" LH surges were not preceded by a large increase in E2 unlike "normal" surges and small elevations of circulating E2 alone were unable to induce LH surges. These results show that the "precocious" LH surge was not the result of E2 positive feedback. Our second aim was to test if noradrenaline (NA) is involved in the LH response to the "ram effect". Using double labelling for Fos and tyrosine hydroxylase (TH) we showed that exposure of anoestrous ewes to a ram induced a higher density of cells positive for both in the A1 nucleus and the Locus Coeruleus complex compared to unstimulated controls. Finally, the administration by retrodialysis into the preoptic area, of NA increased the proportion of ewes with an LH response to ram odor whereas treatment with the α1 antagonist Prazosin decreased the LH pulse frequency and amplitude induced by a sexually active ram. Collectively these results suggest that in anoestrous ewes NA is involved in ram-induced LH secretion as observed in other induced ovulators.

  19. Zinc Oxide Surge Arresters and HVDC 125kV-upgrade 500kV Converter Stations

    NASA Astrophysics Data System (ADS)

    Shirakawa, Shingo; Kobayashi, Takayuki; Matsushita, Yoshinao; Sakai, Takehisa; Suzuki, Hironori; Ozaki, Yuzo

    Gapless Metal (Zinc) Oxide Surge Arresters for a.c. systems contribute to the insulation co-ordination based on the suppression of lightning surges and switching surges. These gapless metal oxide surge arresters using ZnO elements are effective to HVDC systems. This paper describes basic characteristics of ZnO (zinc oxide) elements for d.c. systems and applications of gapless surge arresters to HVDC 125kV frequency converters, HVDC 250kV, upgrade HVDC 500kV converter stations, and HVDC 500kV cables of Japan through the experience of developments and applications of gapless metal oxide surge arresters.

  20. The Uranian satellites - Surface compositions and opposition brightness surges

    NASA Technical Reports Server (NTRS)

    Brown, R. H.; Cruikshank, D. P.

    1983-01-01

    The present, 5 percent-resolution spectrophotometry for the Uranian satellites Ariel, Umbriel, Titania and Oberon cover the 1.43-2.57 wavelength region and confirm the presence of a spectrally dominant water ice component in their surfaces. The 1.5- and 2.0-micron water absorption band depths and continuum reflectance indicate significant differences among the surface compositional properties of the four satellites, and comparisons of the spectra with those of other solar system bodies and of laboratory water ice spectra imply the presence of a significant nonwater ice component on/in their surfaces. The nature of this nonwater ice component is suggested by the data to be similar to that of such substances as carbon black. Near-IR opposition brightness surges of Ariel, Titania and Oberon are found to be among the largest in the solar system.

  1. The Significance of Cross-Bedded Surge Deposits

    NASA Astrophysics Data System (ADS)

    Burgisser, A.; Gardner, J. E.

    2003-12-01

    We characterized cross-beds in surge deposits to distinguish between features that indicate large-scale motions and those controlled by small-scale depositional processes in order to determine the modes of transport (suspended load, traction-dominated) shaping the cross-beds. Surge deposits in the Upper Toluca Pumice at Toluca Volcano, Mexico, were selected because of their well-preserved dune forms and exceptional exposure. We measured the grain size distribution and componentry of representative individual layers as well as the occurrence and shape of the dune forms. Individual surge beds have variable amounts of size sorting, with well-sorted units occurring at all grain sizes. Density sorting is poor, except for the coarse-grain layers. No density sorting of the coarse layers occurs, however, where sub-horizontal bedding merges with poorly sorted, massive deposit. The shape of dune forms is self-similar, as shown by the power law relating their height to their length, and large dunes are frequently followed by a string of smaller dunes immediately downstream, the sizes of which decrease rapidly down current. Both prograde or retrograde dune crests can be present within the same dune form. Previous work has shown that large-scale turbulent structures sort clasts as a function of both size and density, because the viscous force needed to suspend clasts varies linearly with density and with the square of the clast diameter. Thus, the transport system produces clasts sorted in both size and density. On the other hand, processes occurring in the traction-dominated depositional system are little known. Our observations suggest clast transport in the boundary layer was more likely by rotation rather than either sliding, owing to the roughness of the substrate and the angular nature of the clasts, or gravity-induced grain flowage, as the beds dip significantly below the angle of repose of the clasts. We thus propose that rolling causes size sorting to occur regardless

  2. SAPS onset timing during substorms and the westward traveling surge

    NASA Astrophysics Data System (ADS)

    Mishin, Evgeny, V.

    2016-07-01

    We present multispacecraft observations in the magnetosphere and conjugate ionosphere of the onset time of subauroral polarization streams (SAPS) and tens of keV ring current injections on the duskside in three individual substorms. This is probably the first unequivocal determination of the substorm SAPS onset timing. The time lag between the SAPS and substorm onsets is much shorter than the gradient-curvature drift time of ˜10 keV ions in the plasmasphere. It seemingly depends on the propagation time of substorm-injected plasma from the dipolarization onset region to the plasmasphere, as well as on the SAPS position. These observations suggest that fast onset SAPS and ring current injections are causally related to the two-loop system of the westward traveling surge.

  3. Designs for surge immunity in critical electronic facilities

    NASA Technical Reports Server (NTRS)

    Roberts, Edward F., Jr.

    1991-01-01

    In recent years, Federal Aviation Administration (FAA) embarked on a program replacing older tube type electronic equipment with newer solid state equipment. This replacement program dramatically increased the susceptibility of the FAA's facilities to lightning related damages. The proposal is presented of techniques which may be employed to lessen the susceptibility of new FAA electronic facility designs to failures resulting from lightning related surges and transients as well as direct strikes. The general concept espoused is one of a consistent system approach employing both perimeter and internal protection. It compares the technique presently employed to reduce electronic noise with other techniques which reduce noise while lowering susceptibility to lightning related damage. It is anticipated that these techniques will be employed in the design of an Air Traffic Control Tower in a high isokeraunic area. This facility would be subjected to rigorous monitoring over a multi-year period to provide quantitative data hopefully supporting the advantage of this design.

  4. Low voltage, high energy surge arrester for secondary applications

    SciTech Connect

    Kershaw, S.S. Jr.; Goedde, G.L.; Schettler, R.N.

    1993-06-15

    A surge arrester for mounting on the exterior of a transformer having first and second line-potential terminals and a neutral terminal is described, comprising; first and second electrodes electrically connected to the first and second line-potential terminals, respectively; a neutral electrode electrically connected to the neutral terminal, said first, second, and neutral electrodes comprising conducting plates; a first metal oxide varistor having a first facing surface in electrical and physical engagement with said first electrode and having a second facing surface in electrical and physical engagement with said neutral electrode; a second metal oxide varistor having a first facing surface in electrical and physical engagement with said second electrode and having a second facing surface in electrical and physical engagement with said neutral electrode; said first and second metal oxide varistors having a High-Current-Short-duration capability of approximately 40 KA or more; and an insulating material surrounding said electrodes and said metal oxide varistors.

  5. Surge of neurophysiological coherence and connectivity in the dying brain

    PubMed Central

    Borjigin, Jimo; Lee, UnCheol; Liu, Tiecheng; Pal, Dinesh; Huff, Sean; Klarr, Daniel; Sloboda, Jennifer; Hernandez, Jason; Wang, Michael M.; Mashour, George A.

    2013-01-01

    The brain is assumed to be hypoactive during cardiac arrest. However, the neurophysiological state of the brain immediately following cardiac arrest has not been systematically investigated. In this study, we performed continuous electroencephalography in rats undergoing experimental cardiac arrest and analyzed changes in power density, coherence, directed connectivity, and cross-frequency coupling. We identified a transient surge of synchronous gamma oscillations that occurred within the first 30 s after cardiac arrest and preceded isoelectric electroencephalogram. Gamma oscillations during cardiac arrest were global and highly coherent; moreover, this frequency band exhibited a striking increase in anterior–posterior-directed connectivity and tight phase-coupling to both theta and alpha waves. High-frequency neurophysiological activity in the near-death state exceeded levels found during the conscious waking state. These data demonstrate that the mammalian brain can, albeit paradoxically, generate neural correlates of heightened conscious processing at near-death. PMID:23940340

  6. Flood surge through the Lunae Planum Outflow Complex, Mars

    NASA Technical Reports Server (NTRS)

    De Hon, R. A.; Pani, E. A.

    1992-01-01

    It is shown that the Maja outflow on Mars was released as a catastrophic outburst from Juventae Chasma. The flood surge traveled the first two-thirds of its length as a semiconfined sheetflood in a broad trough formed by the eastward-sloping Lunae Planum surface and the Xanthe Terra highlands to the east. At its northernmost extent, the flow ponded on the northern Lunae Planum surface. As the flow impounded on the upper Maja lake, waters rose to spill over the Xanthe Terra revetment onto the lower Chryse Planitia surface. The initial spillover crossed Xanthe Terra as sheetflood flow that muted topography over which it passed. The sheetflood was rapidly broken by the irregular topography to cut a complex series of anastomosing channels. A few main channels on eventually captured most of the drainage and local ponds formed in breached craters and irregular basins. The Maja Valles canyon eventually captured the remaining flow at the expense of all other channels.

  7. Integrating disaster preparedness and surge capacity in emergency facility planning.

    PubMed

    Zilm, Frank; Berry, Robert; Pietrzak, Michael P; Paratore, Amy

    2008-01-01

    The ability to adapt and utilize emergency facilities is a critical element in responding to surges resulting from man-made and natural events. The current stresses on emergency services throughout the country find few adequately prepared to effectively absorb a sudden increase in patients along with some of the potential special requirements, such as quarantining of epidemic patients and mass decontamination. This article reviews major findings of the federally funded ER One project, a research initiative that has described a number of facility strategies, which should be considered in planning new emergency facilities. An early case study in the application of these principles at the recently completed Tampa General Hospital emergency service is provided, illustrating how, when integrated into the early planning and design, many of the ER One recommendations can be implemented at modest capital cost increases.

  8. Coastal Storm Surge Analysis: Storm Forcing. Report 3. Intermediate Submission No. 1.3

    DTIC Science & Technology

    2013-07-01

    37  Figure 2-30. Relative ( percentage ) difference between the stochastic and JPM- predicted, 100-year...return period storm surge elevations. ............................................................... 38  Figure 2-31. Relative ( percentage ) difference between...39  Figure 2-32. Relative ( percentage ) difference between the stochastic and JPM- predicted, 10-year return period storm surge

  9. INCREASED FLEXIBILITY OF TURBO-COMPRESSORS IN NATURAL GAS TRANSMISSION THROUGH DIRECT SURGE CONTROL

    SciTech Connect

    Robert J. Mckee; Danny M. Deffenbaugh

    2003-12-01

    This annual progress report describes the second year's technical progress in a three-year program. This report summarizes what is known about internal flows as surge precursors in centrifugal compressors and focuses on accessing factors that affect pre-surge detection. An attempt is made in this analysis to identify and quantify factors concerning compressor design and operations that affect the detection of pre-surge conditions. This progress report presents results from recent laboratory tests conducted during the course of this second year. This project is co-funded by the Gas Machinery Research Council (GMRC) and by Siemens Energy and Automation (Siemens). The most recently available measured pre-surge internal flow data is parameterized to help identify factors that affect the indications that a compressor is approaching surge. Theoretical arguments are applied to access the factors that influence surge precursors and surge initiation in different centrifugal compressors. This work is considered a step in accessing the factors that affect the success or limitations of pre-surge detection in natural gas pipeline compressors.

  10. Workers With Irregular Hours During Seasonal Work Surges: Promoting Healthy Sleep.

    PubMed

    Butterfield, Patricia

    2016-03-01

    A significant proportion of the labor force works irregular hours during harvest, summer, or holiday work surges. Unfortunately such workers are often uninformed about the importance of sleep and fatigue management. Seasonally timed worker training can improve health and safety outcomes during work surges.

  11. Phase I Report for SERRI Project No. 80037: Investigation of surge and wave reduction by vegetation

    USDA-ARS?s Scientific Manuscript database

    Surge and waves generated by hurricanes and other severe storms can cause devastating damage of property and loss of life in coastal areas. Vegetation in wetlands, coastal fringes and stream floodplains can reduce storm surge and waves while providing ecological benefits and complementing traditiona...

  12. Propagation of a westward traveling surge and the development of persistent auroral features

    NASA Technical Reports Server (NTRS)

    Craven, J. D.; Frank, L. A.; Akasofu, S.-I.

    1989-01-01

    Imaging instrumentation on board the spacecraft Dynamics Explorer 1 (DE 1) is used to observe the large-scale motion of a surge over 7000 km along the auroral oval from near local midnight. Average speed of the surge is 2.2 km/s. Ground-based observations at Fort Yukon, Alaska, show the classical looped, multiple-arc structure of a westward traveling surge as it passes overhead. Within the 6-min temporal resolution provided with DE 1, the surge advances initially at a speed of about 8 km/s followed by a steady decline to about 1 km/s over a period of 17 min. This sequence is then repeated a second time, beginning with a significant intensification of the surge form. This intense surge activity is not accompanied by significant auroral activity near magnetic midnight. Following passage of the surge, persistent and localized bright emission regions remain along the auroral oval for several tens of minutes. Average separation distances are approximately 700 km. If these persistent features identify the sites of individual stepwise advances of the surge, the average time per advance is about 5 min.

  13. Role of exogenous estrogen in initiation of estrus and induction of an LH surge

    USDA-ARS?s Scientific Manuscript database

    Among cattle the LH surge that causes ovulation occurs shortly after the onset of a spontaneous estrus. In addition an injection of 100 'g of GnRH can induce an LH surge capable of inducing ovulation. We hypothesized that different preovulatory estradiol profiles would result in different ovulator...

  14. Effect of Tide Elevation on Extratropical Storm Surge in Northwest Europe

    NASA Astrophysics Data System (ADS)

    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.

  15. Propagation of a westward traveling surge and the development of persistent auroral features

    SciTech Connect

    Craven, J.D.; Frank, L.A. ); Akasofu, S.I. )

    1989-06-01

    Imaging instrumentation on board the spacecraft Dynamics Explorer 1 (DE 1) is used to observe the large-scale motion of a surge over 7,000 km along the auroral oval from near local midnight. Average speed of the surge is 2.2 km/s. Ground-based observations at Fort Yukon, Alaska, show the classical looped, multiple-arc structure of a westward traveling surge as it passes overhead. Within the 6-min temporal resolution provided with DE 1, the surge advances initially at a speed of about 8 km/s followed by a steady decline to about 1 km/s over a period of 17 min. This sequence is then repeated a second time, beginning with a significant intensification of the surge form. This intense surge activity is not accompanied by significant auroral activity near magnetic midnight. Following passage of the surge, persistent and localized bright emission regions remain along the auroral oval for several tens of minutes. Average separation distances are approximately 700 km. If these persistent features identify the sites of individual stepwise advances of the surge, the average time per advance is about 5 min.

  16. Cause of the Infrared Opposition Surge in Saturn's C Ring

    NASA Astrophysics Data System (ADS)

    Turner, Neal J.; Morishima, Ryuji; Spilker, Linda

    2016-10-01

    Saturn's C ring shows an opposition surge at infrared wavelengths, perhaps due to inter or intra-particle surface roughness. Blackbody fits to data from the Cassini spacecraft's Composite Infrared Spectrometer at wavelengths 20-200 um yield temperatures that rise about 4 K per radian as the solar phase angle decreases towards zero, while fits at 13.3-16.7 um yield slopes up to 8 K per radian. We explore ring particle structures compatible with this dependence on phase angle and wavelength, using Monte Carlo radiative transfer modeling. The candidate ring particle is illuminated with photon packets having wavelengths drawn from the Solar spectrum. When absorbed and re-emitted within the particle, the packets are given new wavelengths drawn from the local thermal spectrum. Each packet undergoes repeated scattering, absorption and re-emission till it escapes to infinity, so that energy is conserved exactly. The wavelength-dependent volume absorption and scattering coefficients and scattering anisotropy come from Mie calculations in which we assume the meter-sized ring particle is made up of spherical ice grains with a power-law distribution in size from um to cm. Diffraction is removed by the delta-Eddington method, since the grains lie too close together for the diffraction that occurs around isolated bodies. The Monte Carlo transfer calculations thus treat both regolith radiative transfer and the self-illumination possible on irregular surfaces. The results indicate the opposition surge is consistent with the C ring's particles having significant surface roughness in the form of craters or pits.

  17. Hospital emergency surge capacity: an empiric New York statewide study.

    PubMed

    Kanter, Robert K; Moran, John R

    2007-09-01

    National policy for emergency preparedness calls for hospitals to accommodate surges of 500 new patients per million population in a disaster, but published studies have not evaluated the ability of existing resources to meet these goals. We describe typical statewide and regional hospital occupancy and patterns of variation in occupancy and estimate the ability of hospitals to accommodate new inpatients. Daily hospital occupancy for each hospital was calculated according to admission date and length of stay for each patient during the study period. Occupancy was expressed as the count of occupied beds. Peak hospital capacity was defined as the 95th percentile highest occupancy at each facility. Data obtained from the New York Statewide Planning and Research Cooperative System were analyzed for 1996 to 2002. Patients were classified as children (0 to 14 years, excluding newborns) or adults. Vacant hospital beds per million age-specific population were determined as the difference between peak capacity and average occupancy. In New York State, 242 hospitals cared for a peak capacity of 2,707 children and 46,613 adults. Occupancy averaged 60% of the peak for children and 82% for adults, allowing an average statewide capacity for a surge of 268 new pediatric and 555 adult patients for each million age-specific population. After the September 11, 2001, attacks, in the New York City region, a discretionary modification of admissions and discharges resulted in an 11% reduction from the expected occupancy for children and adults. Typically, there are not enough vacant hospital beds available to serve 500 children per million population. Modified standards of hospital care to expand capacity may be necessary to serve children in a mass-casualty event.

  18. Ground Penetrating Radar Imaging of Tephra Fallout and Surge Deposits

    NASA Astrophysics Data System (ADS)

    Kruse, S.; Martin, K.; Connor, C.; Mora, R.; Ramirez, C.; Alvarado, G.

    2005-05-01

    GPR profiles on Cerro Negro volcano, Nicaragua, and Poás, Irazú, and Arenal volcanoes, Costa Rica, show this method has utility for mapping tephra blanket and surge deposit thicknesses, as well as ballistics distributions. These data are useful for estimating eruption volumes, particularly close to vents where deposits may be thicker than trenching depths. In the dry, highly resistive tephra of the Cerro Negro basaltic cinder cone, distinct deposits are clearly imaged between 2 and 20 m depth. The lowermost coherent reflection is presumed to be the contact with underlying pre-Cerro Negro lavas and weathered tephra deposits. Within the 2-20 m package, individual reflecting horizons are clearly resolved, and reflection attributes, particularly phase, may contain useful information on the nature of contacts, such as abrupt changes in granulometry. Because of the very high velocities at Cerro Negro (0.14 m/ns), even with 200 MHz antennas strata shallower than 2 m are difficult to resolve. In contrast, wetter ash, pumice, paleosol, and surge deposits on Irazú and Poás volcanoes show velocities as low as 0.045 m/ns. The corresponding shorter wavelengths permit strata as shallow as 40-70 cm to be imaged with 200 MHz antennas, with depth penetration typically 5 to 8 m. Comparison of trench observations and radar profiles indicates that strong radar reflections are produced by iron-rich zones at the water table and soil-ash contacts. Other features visible in the profiles are small (tens of cm) sub-vertical offsets of nearly horizontal units, and diffractions or disruptions in horizontal units presumed to reflect >30 cm blocks.

  19. Extreme storm surges: a comparative study of frequency analysis approaches

    NASA Astrophysics Data System (ADS)

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

    2014-08-01

    In France, nuclear facilities were designed around very low probabilities of failure. Nevertheless, some extreme climatic events have given rise to exceptional observed surges (outliers) much larger than other observations, and have clearly illustrated the potential to underestimate the extreme water levels calculated with the current statistical methods. The objective of the present work is to conduct a comparative study of three approaches to extreme value analysis, including the annual maxima (AM), the peaks-over-threshold (POT) and the r-largest order statistics (r-LOS). These methods are illustrated in a real analysis case study. All data sets were screened for outliers. Non-parametric tests for randomness, homogeneity and stationarity of time series were used. The shape and scale parameter stability plots, the mean excess residual life plot and the stability of the standard errors of return levels were used to select optimal thresholds and r values for the POT and r-LOS method, respectively. The comparison of methods was based on (i) the uncertainty degrees, (ii) the adequacy criteria and tests, and (iii) the visual inspection. It was found that the r-LOS and POT methods have reduced the uncertainty on the distribution parameters and return level estimates and have systematically shown values of the 100 and 500-year return levels smaller than those estimated with the AM method. Results have also shown that none of the compared methods has allowed a good fit at the right tail of the distribution in the presence of outliers. As a perspective, the use of historical information was proposed in order to increase the representativeness of outliers in data sets. Findings are of practical relevance, not only to nuclear energy operators in France, for applications in storm surge hazard analysis and flood management, but also for the optimal planning and design of facilities to withstand extreme environmental conditions, with an appropriate level of risk.

  20. Extreme storm surges: a comparative study of frequency analysis approaches

    NASA Astrophysics Data System (ADS)

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

    2013-11-01

    In France, nuclear facilities were designed to very low probabilities of failure. Nevertheless, exceptional climatic events have given rise to surges much larger than observations (outliers) and had clearly illustrated the potential to underestimate the extreme water levels calculated with the current statistical methods. The objective of the present work is to conduct a comparative study of three approaches including the Annual Maxima (AM), the Peaks-Over Threshold (POT) and the r-Largest Order Statistics (r-LOS). These methods are illustrated in a real analysis case study. All the data sets were screened for outliers. Non-parametric tests for randomness, homogeneity and stationarity of time series were used. The shape and scale parameters stability plots, the mean excess residual life plot and the stability of the standard errors of return levels were used to select optimal thresholds and r values for the POT and r-LOS method, respectively. The comparison of methods was based on: (i) the uncertainty degrees, (ii) the adequacy criteria and tests and (iii) the visual inspection. It was found that the r-LOS and POT methods have reduced the uncertainty on the distributions parameters and return level estimates and have systematically shown values of the 100 and 500 yr return levels smaller than those estimated with the AM method. Results have also shown that none of the compared methods has allowed a good fitting at the right tail of the distribution in the presence of outliers. As a perspective, the use of historical information was proposed in order to increase the representativity of outliers in data sets. Findings are of practical relevance not only to nuclear energy operators in France, for applications in storm surge hazard analysis and flood management, but also for the optimal planning and design of facilities to withstand extreme environmental conditions, with an appropriate level of risk.

  1. EXTENT AND MAGNITUDE OF CATECHOLAMINE SURGE IN PEDIATRIC BURNED PATIENTS

    PubMed Central

    Kulp, Gabriela A; Herndon, David N.; Lee, Jong O.; Suman, Oscar E.; Jeschke, Marc G

    2009-01-01

    Increased catecholamine (CA) levels after severe burn are associated with stress, inflammation, hypermetabolism and impaired immune function. The CA secretion profiles in burned patients are not well described. Mechanisms, duration and extent of CA surge are unknown. The purpose of this large unicenter study was to evaluate the extent and magnitude of CA surge following severe burn in pediatric patients. Patients admitted between 1996 and 2008 were enrolled in this study. Twenty-four-hour urine collections were performed during acute hospitalization and up to 2 years post burn. Results from the samples collected from 12 normal, healthy volunteers were compared with the data from the burned patients. Relevant demographic and clinical information was obtained from Medical Records. Student’s t-test and one way ANOVA were used to analyze the data where appropriate. Significance was accepted at p<0.05. Four-hundred thirteen patients were enrolled in this study, 17 patients died during acute hospitalization. Burn caused a marked stress and inflammatory response, indicated by massive tachycardia and elevated pro-inflammatory cytokines. In burned patients, CA levels are consistently and significantly modulated after burn when compared to the levels in normal, healthy volunteers. CA levels were significantly higher in males compared to females, correlated with burn size in burns over 40% and were increased in older children. There were differences over time in survivors vs. non-survivors, with CA levels significantly higher in non-survivors at 2 time points. Inflammatory cytokines show a similar profile during the study period. Our study gives clinicians a useful insight into the extent and magnitude of CA elevation to better design treatment strategies. PMID:20407405

  2. Kelvin-Helmholtz instability in solar cool surges

    NASA Astrophysics Data System (ADS)

    Zhelyazkov, I.; Zaqarashvili, T. V.; Chandra, R.; Srivastava, A. K.; Mishonov, T.

    2015-12-01

    We study the conditions for onset of Kelvin-Helmholtz (KH) instability in a cool solar surge observed in NOAA AR 8227 on 1998 May 30. The jet with speeds in the range of 45-50 km s-1, width of 7 Mm, and electron number density of 3.83 ×1010 cm-3 is assumed to be confined in a twisted magnetic flux tube embedded in a magnetic field of 7 G. The temperature of the plasma flow is of the order of 105 K while that of its environment is taken to be 2 ×106 K. The electron number density of surrounding magnetized plasma has a typical value for the TR/lower corona region of 2 ×109 cm-3. Under these conditions, the Alfvén speed inside the jet is equal to 78.3 km s-1. We model the surge as a moving magnetic flux tube for two magnetic field configurations: (i) a twisted tube surrounded by plasma with homogeneous background magnetic field, and (ii) a twisted tube which environment is plasma with also twisted magnetic field. The magnetic field twist in given region is characterized by the ratio of azimuthal to the axial magnetic field components evaluated at the flux tube radius. The numerical studies of appropriate dispersion relations of MHD modes supported by the plasma flow in both magnetic field configurations show that the Kelvin-Helmholtz instability can only occur for MHD waves propagating in axial direction, but with high negative azimuthal mode numbers, and the instability occurs at sub-Alfvénic critical flow velocities in the range of 24-60 km s-1.

  3. Surge Light-Triggered Thyristor for breaker application. Final report

    SciTech Connect

    Temple, V.A.K.; Holroyd, F.W.

    1985-01-01

    The object of the Surge Light-Triggered Thyristor program was to develop a device useful for breaker applications. Because of the small, but still finite, on-state resistance of all semiconductor devices, it is not considered economical to utilize such devices in series with the power lines in such applications. However, it is a distinct possibility that a parallel combination of semiconductor switch and mechanical breaker might well combine the advantages of both and, at the same time, reduce the requirements that either would need if used alone. The essential idea of this hybrid breaker is to detect the fault through normal means, and then to initiate the opening of the mechanical breaker. After a few hundreds of arc volts have been reached, the parallel semiconductor switch can be closed. Current transfers to the semiconductor switch and the mechanical breaker is open fully and clear. The dielectric and mechanical stresses on the mechanical breaker are much reduced. The semiconductor switch is then opened by an appropriate signal (or lack of signal) on its control electrode leaving the hybrid breaker open and clear. The semiconductor requirements are less stringent than in a purely semiconductor breaker because the semiconductor can be rated solely for surge duty. Moreover, the starting temperature of the semiconductor switch is not raised above ambient by the need to conduct the normal system current. It is hoped that a hybrid breaker will allow breakers to be built that are less costly, more reliable, and that have higher power ratings and faster response and reclosure times.

  4. Identifying surging glaciers in the Central Karakoram for improved climate change impact assessment

    NASA Astrophysics Data System (ADS)

    Paul, Frank; Bolch, Tobias; Mölg, Nico; Rastner, Philipp

    2015-04-01

    Several recent studies have investigated glacier changes in the Karakoram mountain range, a region where glaciers behave differently (mass gain and advancing tongues) compared to most other regions in the world. Attribution of this behaviour to climate change is challenging, as many glaciers in the Karakoram are of surge type and have actively surged in the recent past. The measured changes in length, area, volume or velocity in this region are thus depending on the time-period analysed and include non-climatic components. Hence, a proper analysis of climate change impacts on glaciers in this region requires a separation of the surging from the non-surging glaciers. This is challenging as the former often lack the typical surface characteristics such as looped moraines (e.g. when they are steep and small) and/or they merge (during a surge) with a larger non-surging glacier and create looped moraines on its surface. By analysing time series of satellite images that are available since 1961, the heterogeneous behaviour of glaciers in the Karakoram can be revealed. In this study, we have analysed changes in glacier terminus positions in the Karakoram over different time periods from 1961 to 2014 for several hundred glaciers using Corona KH-4 and KH-4B, Hexagon KH-9, Terra ASTER, and Landsat MSS, TM, ETM+ and OLI satellite data. For the last 15 years, high-speed animations of image time-series reveal details of glacier flow and surge dynamics that are otherwise difficult to detect. For example, several of the larger glaciers with surging tributaries (e.g. Panmah, Sarpo Laggo, Skamri, K2 glacier) are stationary and downwasting despite the mass contributions from the surging glaciers. The analysis of the entire time series reveals a complex pattern of changes through time with retreating, advancing, surging and stationary glaciers that are partly regionally clustered. While most of the non-surging glaciers show only small changes in terminus position (±100 m or less

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

    NASA Astrophysics Data System (ADS)

    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

  6. Local amplification of storm surge by Super Typhoon Haiyan in Leyte Gulf

    PubMed Central

    Mori, Nobuhito; Kato, Masaya; Kim, Sooyoul; Mase, Hajime; Shibutani, Yoko; Takemi, Tetsuya; Tsuboki, Kazuhisa; Yasuda, Tomohiro

    2014-01-01

    Typhoon Haiyan, which struck the Philippines in November 2013, was an extremely intense tropical cyclone that had a catastrophic impact. The minimum central pressure of Typhoon Haiyan was 895 hPa, making it the strongest typhoon to make landfall on a major island in the western North Pacific Ocean. The characteristics of Typhoon Haiyan and its related storm surge are estimated by numerical experiments using numerical weather prediction models and a storm surge model. Based on the analysis of best hindcast results, the storm surge level was 5–6 m and local amplification of water surface elevation due to seiche was found to be significant inside Leyte Gulf. The numerical experiments show the coherent structure of the storm surge profile due to the specific bathymetry of Leyte Gulf and the Philippines Trench as a major contributor to the disaster in Tacloban. The numerical results also indicated the sensitivity of storm surge forecast. PMID:25821268

  7. The reduction of storm surge by vegetation canopies: Three-dimensional simulations

    NASA Astrophysics Data System (ADS)

    Sheng, Y. Peter; Lapetina, Andrew; Ma, Gangfeng

    2012-10-01

    Significant buffering of storm surges by vegetation canopies has been suggested by limited observations and simple numerical studies, particularly following recent Hurricanes Katrina, Rita, and Wilma. Here we simulate storm surge and inundation over idealized topographies using a three-dimensional vegetation-resolving storm surge model coupled to a shallow water wave model and show that a sufficiently wide and tall vegetation canopy reduces inundation on land by 5 to 40 percent, depending upon various storm and canopy parameters. Effectiveness of the vegetation in dissipating storm surge and inundation depends on the intensity and forward speed of the hurricane, as well as the density, height, and width of the vegetation canopy. Reducing the threat to coastal vegetation from development, sea level rise, and other anthropogenic factors would help to protect many coastal regions against storm surges.

  8. Bifurcation analysis of surge and rotating stall in the Moore-Greitzer compression system

    NASA Astrophysics Data System (ADS)

    Hos, Csaba; Champneys, Alan; Kullmann, Laszlo

    2003-04-01

    A simple compression system model, described by a set of three ordinary nonlinear differential equations (the Moore-Greitzer model) is studied using bifurcation analysis to give a qualitative understanding of the presence of surge and rotating stall. First, three parameter values are chosen and a reduced planar system is studied to detect the local bifurcations of pure surge modes. The global bifurcation diagrams are then completed with the help of the continuation software AUTO. A special feature of this 2D system is a set of parameter values where two Takens-Bogdanov points merge. As a next step, the interaction of surge and rotating stall modes is analysed using the same branch tracking technique. Several novel bifurcation scenarios are described. Two-parameter bifurcation maps are computed and a satisfactory agreement with experimental results is found. An explanation is given for the onset of deep surge, rotating stall, classic surge and the hysteresis effects experienced in measurements.

  9. Experiments and modelling of surge in small centrifugal compressor for automotive engines

    SciTech Connect

    Galindo, J.; Serrano, J.R.; Climent, H.; Tiseira, A.

    2008-01-15

    In this paper the surge phenomenon in small centrifugal compressors used for turbocharging internal combustion engines is analyzed. The experimental work was focused on the measurement of compressor behaviour within the surge zone by means of a specifically designed facility. The presented model is based on the introduction of a fluid inertia term that accounts for the non quasi steady effects and the use of a compressor map extended to the surge and negative flows zone obtained from experimental tests. The compressor model was implemented in a one-dimensional gas-dynamic model. The comparison of the modelled and measured evolution of instantaneous pressure during deep surge operation shows good agreement. Furthermore, the model is also able to predict the amplitude and frequency of pressure pulses when the compressor operates in surge with different outlet duct lengths. (author)

  10. Local amplification of storm surge by Super Typhoon Haiyan in Leyte Gulf.

    PubMed

    Mori, Nobuhito; Kato, Masaya; Kim, Sooyoul; Mase, Hajime; Shibutani, Yoko; Takemi, Tetsuya; Tsuboki, Kazuhisa; Yasuda, Tomohiro

    2014-07-28

    Typhoon Haiyan, which struck the Philippines in November 2013, was an extremely intense tropical cyclone that had a catastrophic impact. The minimum central pressure of Typhoon Haiyan was 895 hPa, making it the strongest typhoon to make landfall on a major island in the western North Pacific Ocean. The characteristics of Typhoon Haiyan and its related storm surge are estimated by numerical experiments using numerical weather prediction models and a storm surge model. Based on the analysis of best hindcast results, the storm surge level was 5-6 m and local amplification of water surface elevation due to seiche was found to be significant inside Leyte Gulf. The numerical experiments show the coherent structure of the storm surge profile due to the specific bathymetry of Leyte Gulf and the Philippines Trench as a major contributor to the disaster in Tacloban. The numerical results also indicated the sensitivity of storm surge forecast.

  11. Surges of tidewater glaciers initiated at the terminus: observations and mechanisms

    NASA Astrophysics Data System (ADS)

    Sevestre, Heidi; Benn, Douglas; Luckman, Adrian; Nuth, Chris; Kohler, Jack; Lindback, Katrin; Pettersson, Rickard

    2017-04-01

    There have been numerous reports that surges of tidewater glaciers in Svalbard were initiated at the terminus and propagated up-glacier, in contrast with downglacier-propagating surges of land-terminating glaciers. Most of the tidewater glacier surges were poorly documented, however, and the cause of this anomalous behavior was unknown. In this study we present detailed data on the recent surges of Aavatsmarkbreen and Wahlenbergbreen, two tidewater glaciers in western Spitsbergen. High-resolution time-series of glacier velocities and evolution of surface crevasse patterns clearly show that both surges propagated up-glacier in a series of abrupt steps. Prior to the surges, the glaciers underwent strong retreat and significant steepening of their terminal zones, and in the case of Aavatsmarkbreen this can be shown to have caused a doubling of driving stress between 1990 and surge onset in 2013. We conclude that the surges developed in response to two distinct processes. 1) During the late quiescent phase, the terminal zones underwent gradual acceleration due to steepening and increasing driving stress. 2) Acceleration of the glacier termini caused surface crevasses to propagate up-glacier, allowing surface melt- and rain-water to access the bed. Upward migration of the surge velocities coincided with stepwise the expansion of the crevasse field. Despite a short-lived reactivation in the summer of 2015, the surge of Aavatsmarkbreen terminated gradually, which we interpret as the result of gradual leakage of stored water. The behavior of these glaciers can be understood in terms of the enthalpy cycle model.

  12. A new dynamical index for classification of cold surge types over East Asia

    NASA Astrophysics Data System (ADS)

    Park, Tae-Won; Ho, Chang-Hoi; Jeong, Jee-Hoon; Heo, Jin-Woo; Deng, Yi

    2015-11-01

    The cold surges over East Asia can be classified into wave-train type and blocking type according to their dynamic origins. In the present study, two dynamic indices are proposed to objectively identify cold surge types using potential temperature ( θ) on the dynamic tropopause at 2-potential vorticity units (2-PVU) surface. The two indices are designed to represent primary characteristics of the two types of cold surge. The wave-train index ( WI) is defined as a difference of anomalous θ on the 2-PVU surface between the western North Pacific and northeast China, which captures a southward (northward) intrusion of cold (warm) air mass related to the trough-ridge pattern. The blocking index ( BI) is defined as a difference of anomalous θ between the subarctic region and northeast China, which indicates air mass overturning related to a reversal of the usual meridional θ gradient commonly observed in the occurrence of blocking type cold surge. Composite analyses based on the distribution of the WI and BI clearly demonstrate the dynamic evolutions of corresponding cold surge types. The wave-train cold surge is associated with a southeastward expansion of the Siberian High and northerly wind near surface, which is caused by growing baroclinic waves. During the blocking cold surge, a geopotential height dipole indicating the subarctic blocking and deepening of East Asian coastal trough induces a southward expansion of the Siberian High and northeasterly wind. Compared to the wave-train type, the blocking cold surge exhibits a longer duration and stronger intensity. In the new framework of these dynamic indices, we can detect a third type of cold surge when both the wave-train and the blocking occur together. In addition, we can exclude the events that do not have the essential features of the upper tropospheric disturbances or the subarctic anticyclonic circulation, which are responsible for cold surge occurrence, using the new indices.

  13. Tide-storm surge interaction at the apex of the South Atlantic Bight

    NASA Astrophysics Data System (ADS)

    Feng, X.; Olabarrieta, M.

    2016-02-01

    Tide-storm surge interactions can affect the accuracy in predicting the timing and the extreme water levels during storm events. The analysis of 19-years long tidal gauge records along the US east coast has revealed the appearance of semidiurnal perturbations to storm surges in the mid-South Atlantic Bight. A preliminary study based on observations showed that the semidiurnal surges were highest at the apex of the South Atlantic Bight (Georgia's coast), which is featured by the quasi-standing M2 tide and a wide continental shelf. It was found that these semidiurnal surge events were triggered by the passage of tropical storms and nor'easters. As a consequence of the storm-induced forcing, observed tides were delayed and partially damped with respect to the predictions. Moreover, bottom friction and Coriolis force, via numerical simulations, were found the primary mechanisms in altering the tidal motion under the effect of storm surge. The preliminary study served to contextualize this study in exploring the factors that influence the Tide-surge interactions in the nearshore region of the South Atlantic Bight. Process-oriented models were built to investigate meteorological effect (such as storm parameters) and non-meteorological effect (such as coastline shape, continental shelf slope, sea level rise). Semidiurnal surge's amplitude and duration increased with the upgraded hurricane-wind stress, as well as with the expansion of hurricane's size. Whereas, the intense and length of semidiurnal surge reduced as of tropical cyclone's translation speed increased. For parallel-to-shore cyclones, the intense of semidiurnal surge maximized when the cyclone was at a distance of 1.5-2.0 Radius of Maximum Wind off the coast. Compared with straight shoreline, the curved shape of coastline enhanced the modification to tide and tidal current during storm events. Moreover, the tide-surge interaction increased as the shelf slope decreased.

  14. Global reconstructed daily surge levels from the 20th Century Reanalysis (1871-2010)

    NASA Astrophysics Data System (ADS)

    Cid, Alba; Camus, Paula; Castanedo, Sonia; Méndez, Fernando J.; Medina, Raúl

    2017-01-01

    Studying the effect of global patterns of wind and pressure gradients on the sea level variation (storm surge) is a key issue in understanding the recent climate change effect on the dynamical state of the ocean. The analysis of the spatial and temporal variability of storm surges from observations is a difficult task to accomplish since observations are not homogeneous in time, scarce in space, and moreover, their temporal coverage is limited. A recent global surge database developed by AVISO (DAC, Dynamic Atmospheric Correction) fulfilled the lack of data in terms of spatial coverage, but not regarding time extent, since it only includes the last two decades (1992-2014). In this work, we use the 20th Century Reanalysis V2 (20CR), which spans the years 1871 to 2010, to statistically reconstruct daily maximum surge levels at a global scale. A multivariate linear regression model is fitted between daily mean ERA-interim sea level pressure fields and daily maximum surge levels from DAC. Following, the statistical model is used to reconstruct daily surges using mean sea level pressure fields from 20CR. The verification of the statistical model shows good agreements between DAC levels and the reconstructed surge levels from the 20CR. The validation of the reconstructed surge with tide gauges, distributed throughout the domain, shows good accuracy both in terms of high correlations and small errors. A time series comparison is also depicted at specific tide gauges for the beginning of the 20th century, showing a high concordance. Therefore, this work provides to the scientific community, a daily database of maximum surge levels; which correspond to an extension of the DAC database, from 1871 to 2010. This database can be used to improve the knowledge on historical storm surge conditions, allowing the study of their temporal and spatial variability.

  15. Storm surge and wave simulations in the Gulf of Mexico using a consistent drag relation for atmospheric and storm surge models

    NASA Astrophysics Data System (ADS)

    Vatvani, D.; Zweers, N. C.; van Ormondt, M.; Smale, A. J.; de Vries, H.; Makin, V. K.

    2012-07-01

    To simulate winds and water levels, numerical weather prediction (NWP) and storm surge models generally use the traditional bulk relation for wind stress, which is characterized by a wind drag coefficient. A still commonly used drag coefficient in those models, some of them were developed in the past, is based on a relation, according to which the magnitude of the coefficient is either constant or increases monotonically with increasing surface wind speed (Bender, 2007; Kim et al., 2008; Kohno and Higaki, 2006). The NWP and surge models are often tuned independently from each other in order to obtain good results. Observations have indicated that the magnitude of the drag coefficient levels off at a wind speed of about 30 m s-1, and then decreases with further increase of the wind speed. Above a wind speed of approximately 30 m s-1, the stress above the air-sea interface starts to saturate. To represent the reducing and levelling off of the drag coefficient, the original Charnock drag formulation has been extended with a correction term. In line with the above, the Delft3D storm surge model is tested using both Charnock's and improved Makin's wind drag parameterization to evaluate the improvements on the storm surge model results, with and without inclusion of the wave effects. The effect of waves on storm surge is included by simultaneously simulating waves with the SWAN model on identical model grids in a coupled mode. However, the results presented here will focus on the storm surge results that include the wave effects. The runs were carried out in the Gulf of Mexico for Katrina and Ivan hurricane events. The storm surge model was initially forced with H*wind data (Powell et al., 2010) to test the effect of the Makin's wind drag parameterization on the storm surge model separately. The computed wind, water levels and waves are subsequently compared with observation data. Based on the good results obtained, we conclude that, for a good reproduction of the storm

  16. Storm surges in the White and Barents Seas: formation, statistics, analysis

    NASA Astrophysics Data System (ADS)

    Korablina, Anastasia; Arkhipkin, Victor

    2017-04-01

    Arctic seas storm surges investigation are high priority in Russia due to the active development of offshore oil and gas, construction of facilities in the coastal zone, as well as for the navigation safety. It is important to study the surges variability, to predict this phenomena and subsequent economic losses, thus including such information into the Russian Arctic Development Program 2020. White and Barents Seas storm surges are caused mainly by deep cyclones of two types: "diving" from the north (88% of all cyclones) and Atlantic from the west. The surge height was defined as the excess of the level that was obtained as the difference between the observed level and subtracting tide level and low-frequency level. The period of low-frequency level oscillation was determined by spectral analysis of the in-situ data. ADCIRC model is used for calculating the storm surge height. We did the calculations on unstructured grid with variable step from 50 to 5000 m. The ADCIRC model was based on the data on wind field, the sea level pressure, the concentration of ice reanalysis CFSR (1979-2010) in increments 0.3°, CFSv2 (2011-2015) in increments 0.2°. On the boundary conditions harmonic constants from Finite Element Solution tide model 2004 (FES2004) in increments 1/8° were set. The following stations on the coast Varandey, Pechora Bay, Chosha Bay, Severodvinsk, Onega, Solovki and other were selected for the storm surges statistical analysis in the period 1979-2015. The number of storm surges (> 0.3 m) long-term variability was obtained, the number of surges at a height (m) range (0.3-0.6, 0.6-0.9, 0.9-1.2, >1.2) was estimated. It shows that 1980 and 1998 are the years with the fewest number storms. For example, the largest number of storm surge (53) was observed in 1995 in Varandey. The height of the surge, possible only once in 100 years, is counted. This maximum height (m) of the surge was noted in Varandey (4.1), Chosha Bay (3.4), Barents Sea, Onega Bay (2

  17. Development of Dimensionless Surge Response Functions for Hazard Assessment at Panama City, Florida

    NASA Astrophysics Data System (ADS)

    Taylor, N. R.; Irish, J. L.; Hagen, S. C.; Kaihatu, J. M.; McLaughlin, P. W.

    2013-12-01

    Reliable and robust methods of extreme value analysis in hurricane surge forecasting are of high importance in the coastal engineering profession. The Joint Probability Method (JPM) has become the preferred statistical method over the Historical Surge Population (HSP) method, due to its ability to give more accurate surge predictions, as demonstrated by Irish et. al in 2011 (J. Geophys. Res.). One disadvantage to this method is its high computational cost; a single location can require hundreds of simulated storms, each needing one thousand computational hours or more to complete. One way of overcoming this issue is to use an interpolating function, called a surge response function, to reduce the required number of simulations to a manageable number. These sampling methods, which use physical scaling laws, have been shown to significantly reduce the number of simulated storms needed for application of the JPM method. In 2008, Irish et. al. (J. Phys. Oceanogr.) demonstrated that hurricane surge scales primarily as a function of storm size and intensity. Additionally, Song et. al. in 2012 (Nat. Hazards) has shown that surge response functions incorporating bathymetric variations yield highly accurate surge estimates along the Texas coastline. This study applies the Song. et. al. model to 73 stations along the open coast, and 273 stations within the bays, in Panama City, Florida. The model performs well for the open coast and bay areas; surge levels at most stations along the open coast were predicted with RMS errors below 0.40 meters, and R2 values at or above 0.80. The R2 values for surge response functions within bays were consistently at or above 0.75. Surge levels at most stations within the North Bay and East Bay were predicted with RMS errors below 0.40 meters; within the West Bay, surge was predicted with RMS errors below 0.52 meters. Accurately interpolating surge values along the Panama City coast and bays enables efficient use of the JPM model in order to

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

    NASA Astrophysics Data System (ADS)

    Kjaer, K. H.; Schomacker, A.; Korsgaard, N. J.; Benediktsson, I. O.

    2008-12-01

    Multi-temporal DEMs (Digital Elevation Models) of glaciers and ice streams have successfully been used for extraction of changes in ice volume over time. In this study, we analysed DEMs of the Brúarjökull glacier forefield (Iceland) 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. The surge-type glacier Brúarjökull has experienced six surges during the last four centuries; these are the largest surges known to have occurred in Iceland. During the most recent surge in 1963-64, the glacier advanced 8 km over a period of c. 3 months with a maximum ice flow velocity of 5 m/hr, and 700 km3 of ice were moved downglacier. The continued recession of Brúarjökull since the 1963-64 surge reveals a young landscape consisting of widely spaced and elongated bedrock hills interspaced with shallow sedimentary basins. The majority of the forefield is covered with a basal till sheet 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 sequence that was coupled to the glacier. Elevation differences between the terrain surface in 1945 and 2003 confirm this scenario as huge quantities of sediment was eroded, deformed and transported during the last surge event. On the scale of individual landforms, it appears for a drumlin surface that is has been lowered 20 m from 1945-2003. Dead-ice melting can explain roughly 8 m of this lowering. Thus, the drumlin must have experienced 12 m of subglacial erosion during the 1964 surge. The imprint of at least four landform generations is

  19. The simulation of a storm surge and wave due to Typhoon Sarah using an integrally coupled tide-surge-wave model of the Yellow and East China Seas

    NASA Astrophysics Data System (ADS)

    Yuk, Jin-Hee; Kim, Kyeong Ok; Choi, Byung Ho

    2015-12-01

    The Yellow and East China Seas are characterized by shallow shelf seas, seasonal monsoons and typhoons, especially the Korean Peninsula's western coastal area, which features large tides, a complex coastline and many islands. This study implemented an integrally coupled tide-surge-wave model based on an unstructured grid to evaluate the impact of Typhoon Sarah, which occurred in September of 1959, on the Yellow and East China Seas and, specifically, the southern coast of Korea in terms of waves and storm surges. The model results projected a significant wave height of 2-7 m, a mean wave period of 4-14 sec, and positive surge heights that were 0.3-1 m along the southern coast of Korea. Additional model runs included two independent model runs for waves and tides, and one tide-surge model run was conducted to investigate the interactions in the wave, tide and storm surge processes. The coupled tide-surgewave model reasonably reproduced wave properties and storm surges, but uncoupled models, i.e. independent models, slightly overestimated waves and surges. The wave forces associated with the gradient radiation stress resulted in water being elevated into coastal regions, thereby the water elevation increased onshore and the reverse happened offshore. A possible water level change due to a storm equivalent to Typhoon Sarah in the year 2100 was estimated by considering a mean sea level rise of 70 cm and was generally in the range of 70-100 cm in the Yellow and East China Seas and approximately 68 cm along the southern coast of Korea.

  20. Coastal geohazards and storm surges: The Indian context

    NASA Astrophysics Data System (ADS)

    Murty, K. S.

    2009-04-01

    that hit the Orisaa coast killed more than 15,000 people and rendered more than a million people homeless. Shelters have been built in the cyclone-prone areas on the coast and the communication systems have been modernised. After the 2004 tsunami, a storm surge and tsunami warning system as been set up that operates from Hyderabad. This involved strengthening the exisiting seismological network to indicate near real time occurence of a tsunamigenic earthquake. The surge during the 1977 cyclone was one of the most devastating surges in the recent past along the east coast of India. The Indian Meteorological Department instralled cyclone warning centres on the east coast. Detection radars have been installed that can track cyclones within a range of 400 kms from the coast. Beyond this range, satellite imageries are used. The OCEAN SAT-1 AND 2 serve this purpose. Climate change is expected to cause rise of sea levels and countries with vast coastlines have necessarily to take appropriate steps to face the challenge in future and India is among them.

  1. A research on unsteady period of debris flow surges

    NASA Astrophysics Data System (ADS)

    Arai, Muneyuki

    2017-04-01

    Debris flow is sometimes lots of intermittent surge flows. These many surges are generated in flow instability and it is a kind of roll wave. It is possible to generate the roll wave of shallow water on the experimental flume. In case of constant discharge and uniform flow at upstream, period of generated roll wave is not constant at downstream. A cause for unstable period of roll wave is discussed in this research. A wave equation for roll wave on inclined channel is obtained by the perturbation method considered shallow water momentum equation in case for rectangular cross section, wide width channel B compared with mean depth h0 ( B >> h0 ), channel slope θ tanθ < 1 and Froude number Fr ≥ 1. A obtained non-dimensional wave equation is ∂η' '∂η' ∂2η' ∂3η' ∂τ' + a1η ∂ξ' + a2∂ξ'2 + a3∂ξ'3 = 0 (1) where, a1 = (3/2)c0'2, ( '2 ) ' ' a2 = - (1/2{) 1/c0 - 1/2 tan θ(c0}/u0), (2) a = (1/2) (2 + c'4)/(2c '2)- 3/2 , 3 0 0 η' = η/h0 : fluctuation from mean depth h0, η' = η/h0, ξ' = ξ/h0 = ɛ1 2(x'- t'), ξ = ɛ1 2(x-vp0t), x : axis of flow direction, t : time, vp0 : phase velocity, τ' = (vp0/h0)t = ɛ3 2, τ = ɛ32t, t' = (vp0/h0)t, x' = x/h0, c0' = c0/vp0, c0 = √ ---- gh0cosθ, u0' = u0/c0, u0 : mean velocity, ɛ : parameter of perturbative expansion. Equation (1) is a kind of KdV - Burgers equation. For phase velocity vp0 is long wave velocity c0, that is vp0 = c0, equation (1) becomes Burgers equation. In this state, waves with different wave numbers deform to a wave of wave number one and phase velocity is added some. Then the equation of the phenomenon is shifted back to KdV - Burgers equation from Burgers equation. c0' and u0' are assumed as constant coefficient in equation (1), however u0' is fluctuated by depth fluctuation in flow. Using a2' by linear approximation as a2' = a2(1 + b1η'), equation (1) is ∂η' '∂η' ' ∂2η' ∂3η' ∂τ' + a1η ∂ξ' + a2(1 + b1η )∂ξ'2 + a3∂ξ'3 = 0. (3) Some numerical results of

  2. Modelling the 2013 Typhoon Haiyan storm surge: Effect of waves, offshore winds, tide phase, and translation speed

    NASA Astrophysics Data System (ADS)

    Bilgera, P. H. T.

    2015-12-01

    Super Typhoon Haiyan, with wind speeds exceeding 300 km h-1 (160 knots) generated a storm surge in San Pedro Bay reaching heights of more than 6m in Tacloban City. Delft Dashboard (DDB), an open-source standalone Matlab based graphical user interface linked to the FLOW and WAVE modeling software of Deltares, was used to develop a coupled flow and wave storm surge model to understand the Typhoon Haiyan storm surge development and propagation. Various experiments were designed to determine the effect of waves, the occurrence of offshore winds prior to the surge, tidal phase, and typhoon translation speed on the surge height. Wave coupling decreased the surge height by about 0.5m probably due to energy dissipation from white capping, bottom friction, and depth-induced breaking. Offshore-directed winds before the arrival of the storm eye resulted to receding of the water level in San Pedro and Cancabato Bay, corroborated by eyewitness and tide gauge data. The experiment wherein the offshore winds were removed resulted to no water receding and a surge with a smaller and gentler surge front, pointing to the importance of the initial water level drawdown in contributing to the destructive power of the wave front. With regard to tides, the effect in Tacloban was actually neither linear nor additive to the surge, with higher surge coincident to low tides and lower surge coincident to high tides. Lastly, the model run with typhoon having a slower translation speed than Haiyan was found to generate higher surges.

  3. Modelling the 2013 Typhoon Haiyan Storm Surge: Effect of Waves, Offshore Winds, Tide Phase, and Translation Speed

    NASA Astrophysics Data System (ADS)

    Bilgera, P. H. T.; Villanoy, C.; Cabrera, O.

    2016-02-01

    Super Typhoon Haiyan, with wind speeds exceeding 300 km h-1 (160 knots) generated a storm surge in San Pedro Bay reaching heights of more than 6m in Tacloban City. Delft Dashboard (DDB), an open-source standalone Matlab based graphical user interface linked to the FLOW and WAVE modeling software of Deltares, was used to develop a coupled flow and wave storm surge model to understand the Typhoon Haiyan storm surge development and propagation. Various experiments were designed to determine the effect of waves, the occurrence of offshore winds prior to the surge, tidal phase, and typhoon translation speed on the surge height. Wave coupling decreased the surge height by about 0.5m probably due to energy dissipation from white capping, bottom friction, and depth-induced breaking. Offshore-directed winds before the arrival of the storm eye resulted to receding of the water level in San Pedro and Cancabato Bay, corroborated by eyewitness and tide gauge data. The experiment wherein the offshore winds were removed resulted to no water receding and a surge with a smaller and gentler surge front, pointing to the importance of the initial water level drawdown in contributing to the destructive power of the wave front. With regard to tides, the effect in Tacloban was actually neither linear nor additive to the surge, with higher surge coincident to low tides and lower surge coincident to high tides. Lastly, the model run with typhoon having a slower translation speed than Haiyan was found to generate higher surges.

  4. Projections of extreme storm surge levels along Europe

    NASA Astrophysics Data System (ADS)

    Vousdoukas, Michalis I.; Voukouvalas, Evangelos; Annunziato, Alessandro; Giardino, Alessio; Feyen, Luc

    2016-11-01

    Storm surges are an important coastal hazard component and it is unknown how they will evolve along Europe's coastline in view of climate change. In the present contribution, the hydrodynamic model Delft3D-Flow was forced by surface wind and atmospheric pressure fields from a 8-member climate model ensemble in order to evaluate dynamics in storm surge levels (SSL) along the European coastline (1) for the baseline period 1970-2000; and (2) during this century under the Representative Concentration Pathways RCP4.5 and RCP8.5. Validation simulations, spanning from 2008 to 2014 and driven by ERA-Interim atmospheric forcing, indicated good predictive skill (0.06 m < RMSE < 0.29 m and 10 % < RMSE < 29 % for 110 tidal gauge stations across Europe). Peak-over-threshold extreme value analysis was applied to estimate SSL values for different return periods, and changes of future SSL were obtained from all models to obtain the final ensemble. Values for most scenarios and return periods indicate a projected increase in SSL at several locations along the North European coastline, which is more prominent for RCP8.5 and shows an increasing tendency towards the end of the century for both RCP4.5 and RCP8.5. Projected SSL changes along the European coastal areas south of 50°N show minimal change or even a small decrease, with the exception of RCP8.5 under which a moderate increase is projected towards the end of the century. The present findings indicate that the anticipated increase in extreme total water levels due to relative sea level rise (RSLR), can be further enforced by an increase of the extreme SSL, which can exceed 30 % of the RSLR, especially for the high return periods and pathway RCP8.5. This implies that the combined effect could increase even further anticipated impacts of climate change for certain European areas and highlights the necessity for timely coastal adaptation and protection measures. The dataset is publicly available under this link: http://data.jrc.ec.europa.eu/collection/LISCOAST.

  5. Application of regional frequency analysis to the estimation of extreme storm surges

    NASA Astrophysics Data System (ADS)

    Bernardara, Pietro; Andreewsky, Marc; Benoit, Michel

    2011-02-01

    Traditionally, extreme value theory is applied to single-site series of surge observations in order to estimate the probability of occurrence of extreme events at that particular site. However, single-site analyses give uncertain estimation of extreme quantiles, mainly because of the limited duration of observation periods. In order to reduce this uncertainty, regional frequency analysis (RFA) approaches suggest collecting information not only from a single-site series but also from all (statistically) similar available series of observation. The use of RFA is widely increasing in geosciences, but few applications have been attempted yet for surge estimation. The aim of this study is to examine the applicability of RFA to extreme storm surges. The surge data observed at 18 French harbors, located on the Atlantic coast from the Spanish to Belgian borders, were collected. The series span a period of 30 years, on average, with the longest series going back to the 19th century. Stationary and independent samples of extreme surges (peaks over a given threshold) are extracted and their (statistical) homogeneity has been tested via heterogeneity and discordancy measures based on L moments. Homogeneous regions have been identified and, in order to merge information on frequency of occurrence of surges from all the sites, a surge index pooling method is defined. Finally, a regional frequency distribution has been estimated. The hypothesis and the applicability of RFA application are discussed, with some ideas for future developments in the research direction.

  6. The role of basal hydrology in the surging of the Laurentide Ice Sheet

    NASA Astrophysics Data System (ADS)

    Roberts, William H. G.; Payne, Antony J.; Valdes, Paul J.

    2016-08-01

    We use the Glimmer ice sheet model to simulate periodic surges over the Laurentide Ice Sheet during the Last Glacial Maximum. In contrast to previous studies we use the depth of water at the base of the ice sheet as the switch for these surges. We find that the surges are supported within the model and are quite robust across a very wide range of parameter choices, in contrast to many previous studies where surges only occur for rather specific cases. The robustness of the surges is likely due to the use of water as the switch mechanism for sliding. The statistics of the binge-purge cycles resemble observed Heinrich events. The events have a period of between 10 and 15 thousand years and can produce fluxes of ice from the mouth of Hudson Strait of 0.05 Sv - a maximum flux of 0.06 Sv is possible. The events produce an ice volume of 2.50 × 106 km3, with a range of 4.30 × 106-1.90 × 106 km3 possible. We undertake a suite of sensitivity tests varying the sliding parameter, the water drainage scheme, the sliding versus water depth parameterisation and the resolution, all of which support the ice sheet surges. This suggests that internally triggered ice sheet surges were a robust feature of the Laurentide Ice Sheet and are a possible explanation for the observed Heinrich events.

  7. Moisture surges over the Gulf of California and relationships with convective activity

    NASA Astrophysics Data System (ADS)

    Mejia-Valencia, John Fredy

    The North American Monsoon (NAM) is characterized by widespread convective activity and rainfall that is tied to key synoptic and sub-synoptic atmospheric circulation features during summer - from mid-June to September. The core monsoon region, particularly over southwestern United States and around the Gulf of California (GoC), often experiences atmospheric phenomena recognized in the literature as "moisture surges". These moisture surges represent one of the most important sources of rainfall variability in the NAM core region with important implications in the hydroclimate and the water resources management in this semiarid region. Although there are a number of studies relating NAM synoptic-scale conditions with moisture surges and regional rainfall patterns, the interactions between atmospheric phenomena of differing scales still remains under-investigated. The overall objective of this research is to improve the understanding of how smaller-spatial scale atmospheric processes modify the evolution of larger-scale atmospheric conditions over the NAM domain. More specifically, this study aims to determine the relationship between organized mesoscale convective systems (MCSs) and moisture surges, and their associated synoptic forcings in the form of Tropical Easterly Waves (TEW), and eastern Pacific Tropical Storms (TS)/Tropical Cyclones (TC). Similarly, relationships were determined between MCSs and GoC low-level jet (GCLLJ). The present research uses three approaches to determine the links between MCSs and moisture surges. A first component of the research consisted of a detailed analyses of a well-observed moisture surge event that occurred during the North American Monsoon Experiment (NAME-2004). Analyses of aircraft flight-level data, together with other special and routine observations are used to describe the four-dimensional structure of this surge event. Theory and observations indicate that this surge's leading edge resembles a solitary Kelvin wave

  8. Tide-surge interaction off the east coast of Canada and northeastern United States

    NASA Astrophysics Data System (ADS)

    Bernier, N. B.; Thompson, K. R.

    2007-06-01

    Sea level observations and a dynamical model are used to investigate tide-surge interaction in the coastal waters off the east coast of Canada and northern USA. The study is motivated in part by the need to improve operational forecasts of total water level and coastal flooding. Two statistical methods are used to search for evidence of tide-surge interaction in hourly sea level records from 23 coastal locations. The methods are based on comparison of the statistical properties of the sea level residuals (observed sea level minus tide) occurring at different stages of the tidal cycle. While recognizing the limitations of such an approach, it is concluded that tide-surge interaction does occur in the Northumberland Strait which is located in the southern Gulf of St. Lawrence. Results for the Gulf of Maine and Bay of Fundy are less conclusive. A dynamical model is also used to quantify tide-surge interaction in the study region and to identify its physical causes. Tide-surge interaction in the model is strongest in the Northumberland Strait where the amplitude of the effect can reach 20 cm during and following strong storm surge events. This is large enough to be of practical significance in terms of flood forecasting. A series of sensitivity experiments with the model shows that the nonlinear parameterization of bottom stress is the principal contributor to tide-surge interaction.

  9. Study on the storm surges induced by cold waves in the Northern East China Sea

    NASA Astrophysics Data System (ADS)

    Mo, Dongxue; Hou, Yijun; Li, Jian; Liu, Yahao

    2016-08-01

    Cold wave, a kind of severe weather system, can bring strong wind and induce significant sea level rise to the Northern East China Sea. Based on CFSR data, the study shows the monthly distributions of invaded days and the spatiotemporal distributions of cold-wave wind direction and wind speed. A three-dimensional numerical model (ROMS) was developed to study storm surges induced by cold waves. The role of wind direction, wind speed, wind duration, extratropical cyclone and tide-surge interaction is investigated by conducting different sensitivity experiments. The results indicate that storm surges mainly happen at the coasts perpendicular to the wind directions. Surge range and time lag are related to the geometry of the basin and the continental shelf. The response of the sea-level fluctuations to cold wave indicates that there is a positive correlation between crests and wind speed, a negative correlation between troughs and wind speed, but no obvious correlations to wind duration. Coupled weather cold waves, which yield a larger range and a multi-peak structure of surges, can be classified according to cold wave tracks and extratropical cyclones. The tide-surge interaction has an obvious and different effect on the magnitudes and phases of storm surges for different tidal stages.

  10. A preliminary study on the intensity of cold wave storm surges of Laizhou Bay

    NASA Astrophysics Data System (ADS)

    Li, Xue; Dong, Sheng

    2016-12-01

    Dike failure and marine losses are quite prominent in Laizhou Bay during the period of cold wave storm surges because of its open coastline to the north and flat topography. In order to evaluate the intensity of cold wave storm surge, the hindcast of marine elements induced by cold waves in Laizhou Bay from 1985 to 2004 is conducted using a cold wave storm surge-wave coupled model and the joint return period of extreme water level, concomitant wave height, and concomitant wind speed are calculated. A new criterion of cold wave storm surge intensity based on such studies is developed. Considering the frequency of cold wave, this paper introduces a Poisson trivariate compound reconstruction model to calculate the joint return period, which is closer to the reality. By using the newly defined cold wave storm surge intensity, the `cold wave grade' in meteorology can better describe the severity of cold wave storm surges and the warning level is well corresponding to different intensities of cold wave storm surges. Therefore, it provides a proper guidance to marine hydrological analysis, disaster prevention and marine structure design in Laizhou Bay.

  11. Maternal adrenalectomy eliminates a surge of plasma dehydroepiandrosterone in the mother and attenuates the prenatal testosterone surge in the male fetus.

    PubMed

    Sinha, P; Halasz, I; Choi, J F; McGivern, R F; Redei, E

    1997-11-01

    Previous work has established a number of sex-related deficits in immune function, behavior, and endocrine responses to stress in the offspring of dams exposed to ethanol. To examine the potential role of maternal glucocorticoids as a mediator of these sexually dimorphic effects in the fetus, we examined the influence of prenatal alcohol exposure in the presence or absence of maternal glucocorticoids on fetal plasma corticosterone (CORT) production. An additional question to be addressed by these studies was whether maternal adrenalectomy could eliminate the known inhibition by ethanol of the prenatal surge of plasma testosterone in male fetuses. Pregnant dams were adrenalectomized (ADX) or sham-adrenalectomized on gestational day (G) 7 and placed on a liquid diet containing 35% ethanol-derived calories or pair-fed an isocaloric control diet throughout the experiment. On G18, G19, and G21, plasma levels of CORT, testosterone, and dehydroepiandrosterone (DHEA) were measured in male and female fetuses and their mothers. Ethanol administration consistently increased maternal plasma CORT levels but did not significantly alter CORT levels in the fetus. Maternal ADX resulted in compensatory increases in fetal CORT levels that were lower in fetuses of ADX dams on alcohol, suggesting a direct effect of ethanol on fetal pituitary-adrenal activity. There were no significant sex differences in fetal plasma CORT levels in response to any of these manipulations. A novel surge of maternal plasma DHEA was found on G19 that was absent in plasma from ADX dams. In spite of the absence of a surge on G19, plasma DHEA levels of ADX dams rose from very low levels at G18 to levels on G21 that were significantly higher than in Sham dams. A normal testosterone surge was observed in male fetuses on G18 and G19 from sham-adrenalectomized dams administered the pair-fed diet. However, this surge was greatly attenuated in males administered ethanol and also in male fetuses from ADX dams. These

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

    NASA Astrophysics Data System (ADS)

    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

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

    NASA Astrophysics Data System (ADS)

    Tablazon, Judd; Mahar Francisco Lagmay, Alfredo; Francia Mungcal, Ma. Theresa; Gonzalo, Lia Anne; Dasallas, Lea; Briones, Jo Brianne Louise; Santiago, Joy; Suarez, John Kenneth; Lapidez, John Phillip; Caro, Carl Vincent; Ladiero, Christine; Malano, Vicente

    2014-05-01

    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 08 November 2013 where more than 6,000 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 (JMA) 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-minute 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

  14. THE KINEMATICS AND PLASMA PROPERTIES OF A SOLAR SURGE TRIGGERED BY CHROMOSPHERIC ACTIVITY IN AR11271

    SciTech Connect

    Kayshap, P.; Srivastava, Abhishek K.; Murawski, K.

    2013-01-20

    We observe a solar surge in NOAA AR11271 using the Solar Dynamics Observatory (SDO) Atmospheric Imaging Assembly 304 A image data on 2011 August 25. The surge rises vertically from its origin up to a height of Almost-Equal-To 65 Mm with a terminal velocity of Almost-Equal-To 100 km s{sup -1}, and thereafter falls and fades gradually. The total lifetime of the surge was Almost-Equal-To 20 minutes. We also measure the temperature and density distribution of the observed surge during its maximum rise and find an average temperature and a density of 2.0 MK and 4.1 Multiplication-Sign 10{sup 9} cm{sup -3}, respectively. The temperature map shows the expansion and mixing of cool plasma lagging behind the hot coronal plasma along the surge. Because SDO/HMI temporal image data do not show any detectable evidence of significant photospheric magnetic field cancellation for the formation of the observed surge, we infer that it is probably driven by magnetic-reconnection-generated thermal energy in the lower chromosphere. The radiance (and thus the mass density) oscillations near the base of the surge are also evident, which may be the most likely signature of its formation by a reconnection-generated pulse. In support of the present observational baseline of the triggering of the surge due to chromospheric heating, we devise a numerical model with conceivable implementation of the VAL-C atmosphere and a thermal pulse as an initial trigger. We find that the pulse steepens into a slow shock at higher altitudes which triggers plasma perturbations exhibiting the observed features of the surge, e.g., terminal velocity, height, width, lifetime, and heated fine structures near its base.

  15. A numerical study on hurricane-induced storm surge and inundation in Charleston Harbor, South Carolina

    NASA Astrophysics Data System (ADS)

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

    2006-08-01

    A storm surge and inundation model is configured in Charleston Harbor and its adjacent coastal region to study the harbor's response to hurricanes. The hydrodynamic component of the modeling system is based on the Princeton Ocean Model, and a scheme with multiple inundation speed options is imbedded in the model for the inundation calculation. Historic observations (Hurricane Hugo and its related storm surge and inundation) in the Charleston Harbor region indicate that among three possible inundation speeds in the model, taking Ct (gd)1/2 (Ct is a terrain-related parameter) as the inundation speed is the best choice. Choosing a different inundation speed in the model has effects not only on inundation area but also on storm surge height. A nesting technique is necessary for the model system to capture the mesoscale feature of a hurricane and meanwhile to maintain a higher horizontal resolution in the harbor region, where details of the storm surge and inundation are required. Hurricane-induced storm surge and inundation are very sensitive to storm tracks. Twelve hurricanes with different tracks are simulated to investigate how Charleston Harbor might respond to tracks that are parallel or perpendicular to the coastline or landfall at Charleston at different angles. Experiments show that large differences of storm surge and inundation may have occurred if Hurricane Hugo had approached Charleston Harbor with a slightly different angle. A hurricane's central pressure, radius of maximum wind, and translation speed have their own complicated effects on surge and inundation when the hurricane approaches the coast on different tracks. Systematic experiments are performed in order to illustrate how each of such factors, or a combination of them, may affect the storm surge height and inundation area in the Charleston Harbor region. Finally, suggestions are given on how this numerical model system may be used for hurricane-induced storm surge and inundation forecasting.

  16. The influence of domain size on the response characteristics of a hurricane storm surge model

    NASA Astrophysics Data System (ADS)

    Blain, C. A.; Westerink, J. J.; Luettich, R. A.

    1994-09-01

    The influence of domain size on boundary condition specification and on computed storm surge response is investigated. Storm surge response along the Florida shelf in the Gulf of Mexico due to Hurricane Kate is examined over three domains using two different open ocean boundary forcing functions, a still water (or zero elevation) condition and an inverted barometer condition which accounts for the atmospheric pressure component of the meteorological forcing. The first domain is relatively small and is situated primarily on the continental shelf in the region of intense storm surge generation. A second domain includes the entire Gulf of Mexico basin. The final domain covers the Gulf of Mexico, contiguous basins, and extends out into the deep Atlantic Ocean. The computed storm surge response indicates that the small domain is inadequate, since cross-shelf boundaries are in regions of significant storm surge generation where surge and therefore boundary conditions are not known a priori. Also, the behavior of resonant modes that are physically excited within the Gulf of Mexico due to the passage of the hurricane is unknown at the boundaries of this small domain. The domain that includes the entire Gulf of Mexico captures the primary storm surge well but may not correctly model resonant modes. In general, these resonant modes are difficult to accurately set up by boundary condition specification, since they may be dependent on interactions between the Gulf and contiguous basins. The primary storm surge response as well as resonant modes excited by the storm are best represented using a domain which encompasses the western North Atlantic Ocean, the Caribbean Sea, and the Gulf of Mexico. This domain with deep Atlantic Ocean boundaries facilitates simple boundary condition specification and minimizes the influence of boundary conditions on storm surge generation in coastal regions. Basin resonant modes and basin to basin interactions are also captured.

  17. Analyses of a surging outlet glacier of Vatnajökull ice cap, Iceland

    NASA Astrophysics Data System (ADS)

    Ađalgeirsdóttir, Guðfinna; Björnsson, Helgi; Pálsson, Finnur; Magnússon, Eyjólfur

    Many of the large outlet glaciers of Vatnajökull ice cap, Iceland, have a history of regular surges. The mass transport during surges can be up to 25% of the total ice flux. This is a considerable amount that affects the whole ice cap, the location of the ice divides, the flow field and the size and shape of the ice cap. Data from the surging outlet Dyngjujökull, on the northern side of Vatnajökull, which surged during the period 1998-2000, are presented: surface elevation changes, displacement and total mass tr ansport. The total gain in ice volume in the receiving area, due to the surge, is considerably smaller than the loss in the reservoir area. The difference is mainly due to enhanced melting rates on the larger surface area of the crevassed glacier surface, and increased turbulent fluxes above the surface, but also due to increased frictional melting at the bed during the surge. A two-dimensional vertically integrated numerical flow model, of standard shallow-ice approximation type, is used to show that a modeled glacier that is similar in size to Dyngjujökull and subject to the same mass balance has three times higher velocities than the measured velocity during the quiescent phase. Adding surges in the numerical model, by periodically increasing the sliding velocity, causes the glacier to retreat and oscillate around a smaller state when subject to the same mass-balance regime. Lowering the equilibrium line by 50 m lets the modeled surging glacier oscillate around a size similar to that of the present glacier, indicating that surging is an efficient long-term ablation mechanism.

  18. The influence of coastal wetlands on hurricane surge in Corpus Christi, TX

    NASA Astrophysics Data System (ADS)

    Ferreira, C.; Irish, J. L.; Olivera, F.

    2010-12-01

    The State of Texas has historically faced hurricane-related damage episodes, with Ike being the most recent example. It is expected that, in the future, hurricanes will intensify due to climate change causing greater surges, while the attenuating effect of wetlands on storm surges will also be modified due to sea level rise changes in wetland vegetation type and spatial location. Numerical analysis of storm surges is an important instrument to predict and simulate flooding extent and magnitude in coastal areas. Most operational surge models account for the influence of wetlands and other vegetation by momentum loss due to friction at the bottom and by reduction of imposed wind stress. A coupled hydrodynamic model (ADCIRC) and wave model (SWAN) was employed, and wetlands were characterized using Manning’s n, surface canopy, and surface roughness. The wetlands parameters were developed from: 1) the National Land Cover Dataset (NLCD) 1992 and 2001; 2) the National Wetlands Inventory (NWI) 2001. The calibrated coupled model for two historical hurricanes, Bret and Beulah, was used to simulate the storm surge for each scenario. Preliminary results for the sensitivity analyses, for hurricane Bret, comparing the scenarios with parameters developed from NLCD and NWI datasets with four hypothetical scenarios considering very high and low Manning’s n and wind stress (surface canopy) values showed that, for areas inside Nueces Bay, the storm surge high could vary up to four times depending on the parameter selection, for areas inside Corpus Christi Bay, the storm surge high varied around three times and behind the barrier island the storm surge high variation was less than three times. This study is a first step for an evaluation of the impact that sea level rise, climate changed wetlands, wetlands restoration, land use change, and wetlands degradation have on hurricane related surge elevation and extent in the city of Corpus Christi.

  19. A global record of large storm surges and loss of life

    NASA Astrophysics Data System (ADS)

    Bouwer, Laurens; Jonkman, Sebastiaan

    2017-04-01

    Storm surges can cause very high numbers of loss of life (fatalities) in single events, and these events are expected to increase due to sea-level rise and increasing population in coastal zones. However, compared to fatalities from fresh water flooding, for storm surges these fatality numbers are not consistently recorded, and often neglected in scientific assessments. In order to assess the impacts of major coastal storm surge events at the global level, we have developed a record of these events and associated loss of life. Information was compiled from the EM-DAT database for the period 1900-2013, using the two key categories of "Tropical cyclone" and "Storm surge/coastal flood", complemented with other databases and sources of information, and records of observed surge levels. We find that globally, each year on average about 8,500 people are killed and 1.3 million people are affected by storm surges. The occurrence of very substantial loss of life (>10,000 persons) from single events has decreased over time, which is in contrast with the slight increasing trends in fatalities observed for fresh water flooding. Also, there is a consistent and strong decrease in event mortality, which is the fraction of the people exposed to surges that lose their life, for all global regions, except South-East Asia. Thus, reduction in vulnerability to loss of life over time plays a significant role in storm surge impacts. We also find that for the same coastal surge water level, mortality appears to have decreased over time, showing the robustness of this finding. This quantified decline can be attributed to risk reduction efforts over the last decades, including improved forecasting, early warning and evacuation, but also improved coastal protection. These results have important implications for assessment studies on current and projected future coastal flood risk, as historical mortality fractions may not be valid to assess impacts from future events.

  20. Experimental and Theoretical Studies of Surging in Continuous-Flow Compressors

    NASA Technical Reports Server (NTRS)

    Bullock, Robert O; Wilcox, Ward W; Moses, Jason J

    1946-01-01

    Experiments have been conducted to determine the conditions that cause surging in compressors and to determine the effect of various installations and operating conditions on the character of the velocity and pressure variations occurring during surging. These investigations were made on three compressor units and the variation of static, total, and velocity pressure with time was recorded. In addition to the experimental studies, a simplified analysis was made to determine how instability of flow may occur in a compressor. Based on this analysis, an examination was made of several possible methods of inhibiting the occurrence of surging.

  1. Protection against lightning surge voltages on communication lines and power lines

    SciTech Connect

    Haseborg, J.L.t.; Trinks, H.

    1983-01-01

    Sensitive electronic systems are shielded against electromagnetic interferences (lightning, EMP). The shielding efficiency is reduced by field coupling through apertures and particularly by feeding of interfering currents through cable entries. In case these cables are connected to the inputs of electronic devices, the surge voltages may disturb or even destroy these devices or single electronic components, particularly semiconductors. Special passive protection circuits for communication and power lines against lightning- and EMP-induced surge voltages are developed. The edge steepnesses of the applying surge voltages show values of 2kV/us (lightning) up to 2kV/ns (EMP).

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

    NASA Astrophysics Data System (ADS)

    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

  3. The Danger of Deja Vu: Why the Iraq Surge is Not a Lesson for Afghanistan

    DTIC Science & Technology

    2010-01-01

    JAN 2010 2. REPORT TYPE 3. DATES COVERED 00-12-2009 to 00-01-2010 4. TITLE AND SUBTITLE The danger of deja vu . Why the Iraq surge is not a lesson...of five brigade combat teams — eerily mim- icked the surge number for Iraq. And there was more déjà vu when our senior civilian and military leaders...Department. PERSPECTIVES The danger of déjà vu Why the Iraq surge is not a lesson for Afghanistan BY COL. CHARLES D. ALLEN (RET.) The thing we take hold of

  4. A Practical Method for Assessing the Effectiveness of Vector Surge Relays for Distributed Generation Applications

    SciTech Connect

    Freitas, Walmir; Huang, Zhenyu; Xu, Wilsun

    2005-01-01

    This paper presents simple and reliable method for predicting the islanding detection performance of vector surge relays. The relay performance is characterized by a tripping-time versus power-imbalance curve. With the curve, one can determine the time taken by a vector surge relay to detect islanding for any generation-load mismatch level. The main contribution of this paper is the development of analytical formulas for directly determining the behavior of vector surge relays. As a result, efforts needed to asses the relay performance for a given distributed generation scheme can be simplified significantly. The accuracy of the formulas has been verified by extensive simulation study results.

  5. Smart Ultrasound Remote Guidance Experiment (SURGE) Preliminary Findings

    NASA Technical Reports Server (NTRS)

    Hurst, Victor; Dulchavsky, Scott; Garcia, Kathleen; Sargsyan, Ashot; Ebert, Doug

    2009-01-01

    To date, diagnostic quality ultrasound images were obtained aboard the International Space Station (ISS) using the ultrasound of the Human Research Facility (HRF) rack in the Laboratory module. Through the Advanced Diagnostic Ultrasound in Microgravity (ADUM) and the Braslet-M Occlusion Cuffs (BRASLET SDTO) studies, non-expert ultrasound operators aboard the ISS have performed cardiac, thoracic, abdominal, vascular, ocular, and musculoskeletal ultrasound assessments using remote guidance from ground-based ultrasound experts. With exploration class missions to the lunar and Martian surfaces on the horizon, crew medical officers will necessarily need to operate with greater autonomy given communication delays (round trip times of up to 5 seconds for the Moon and 90 minutes for Mars) and longer periods of communication blackouts (due to orbital constraints of communication assets). The SURGE project explored the feasibility and training requirements of having non-expert ultrasound operators perform autonomous ultrasound assessments in a simulated exploration mission outpost. The project aimed to identify experience, training, and human factors requirements for crew medical officers to perform autonomous ultrasonography. All of these aims pertained to the following risks from the NASA Bioastronautics Road Map: 1) Risk 18: Major Illness and Trauna; 2) Risk 20) Ambulatory Care; 3) Risk 22: Medical Informatics, Technologies, and Support Systems; and 4) Risk 23: Medical Skill Training and Maintenance.

  6. Observation impact analysis methods for storm surge forecasting systems

    NASA Astrophysics Data System (ADS)

    Verlaan, Martin; Sumihar, Julius

    2016-02-01

    This paper presents a simple method for estimating the impact of assimilating individual or group of observations on forecast accuracy improvement. This method is derived from the nsemble-based observation impact analysis method of Liu and Kalnay (Q J R Meteorol Soc 134:1327-1335, 2008). The method described here is different in two ways from their method. Firstly, it uses a quadratic function of model-minus-observation residuals as a measure of forecast accuracy, instead of model-minus-analysis. Secondly, it simply makes use of time series of observations and the corresponding model output generated without data assimilation. These time series are usually available in an operational database. Hence, it is simple to implement. It can be used before any data assimilation is implemented. Therefore, it is useful as a design tool of a data assimilation system, namely for selecting which observations to assimilate. The method can also be used as a diagnostic tool, for example, to assess if all observation contributes positively to the accuracy improvement. The method is applicable for systems with stationary error process and fixed observing network. Using twin experiments with a simple one-dimensional advection model, the method is shown to work perfectly in an idealized situation. The method is used to evaluate the observation impact in the operational storm surge forecasting system based on the Dutch Continental Shelf Model version 5 (DCSMv5).

  7. Lightning and surge protection of large ground facilities

    NASA Astrophysics Data System (ADS)

    Stringfellow, Michael F.

    1988-04-01

    The vulnerability of large ground facilities to direct lightning strikes and to lightning-induced overvoltages on the power distribution, telephone and data communication lines are discussed. Advanced electrogeometric modeling is used for the calculation of direct strikes to overhead power lines, buildings, vehicles and objects within the facility. Possible modes of damage, injury and loss are discussed. Some appropriate protection methods for overhead power lines, structures, vehicles and aircraft are suggested. Methods to mitigate the effects of transients on overhead and underground power systems as well as within buildings and other structures are recommended. The specification and location of low-voltage surge suppressors for the protection of vulnerable hardware such as computers, telecommunication equipment and radar installations are considered. The advantages and disadvantages of commonly used grounding techniques, such as single point, multiple and isolated grounds are compared. An example is given of the expected distribution of lightning flashes to a large airport, its buildings, structures and facilities, as well as to vehicles on the ground.

  8. Projected Atlantic hurricane surge threat from rising temperatures.

    PubMed

    Grinsted, Aslak; Moore, John C; Jevrejeva, Svetlana

    2013-04-02

    Detection and attribution of past changes in cyclone activity are hampered by biased cyclone records due to changes in observational capabilities. Here, we relate a homogeneous record of Atlantic tropical cyclone activity based on storm surge statistics from tide gauges to changes in global temperature patterns. We examine 10 competing hypotheses using nonstationary generalized extreme value analysis with different predictors (North Atlantic Oscillation, Southern Oscillation, Pacific Decadal Oscillation, Sahel rainfall, Quasi-Biennial Oscillation, radiative forcing, Main Development Region temperatures and its anomaly, global temperatures, and gridded temperatures). We find that gridded temperatures, Main Development Region, and global average temperature explain the observations best. The most extreme events are especially sensitive to temperature changes, and we estimate a doubling of Katrina magnitude events associated with the warming over the 20th century. The increased risk depends on the spatial distribution of the temperature rise with highest sensitivity from tropical Atlantic, Central America, and the Indian Ocean. Statistically downscaling 21st century warming patterns from six climate models results in a twofold to sevenfold increase in the frequency of Katrina magnitude events for a 1 °C rise in global temperature (using BNU-ESM, BCC-CSM-1.1, CanESM2, HadGEM2-ES, INM-CM4, and NorESM1-M).

  9. Projected Atlantic hurricane surge threat from rising temperatures

    PubMed Central

    Grinsted, Aslak; Moore, John C.; Jevrejeva, Svetlana

    2013-01-01

    Detection and attribution of past changes in cyclone activity are hampered by biased cyclone records due to changes in observational capabilities. Here, we relate a homogeneous record of Atlantic tropical cyclone activity based on storm surge statistics from tide gauges to changes in global temperature patterns. We examine 10 competing hypotheses using nonstationary generalized extreme value analysis with different predictors (North Atlantic Oscillation, Southern Oscillation, Pacific Decadal Oscillation, Sahel rainfall, Quasi-Biennial Oscillation, radiative forcing, Main Development Region temperatures and its anomaly, global temperatures, and gridded temperatures). We find that gridded temperatures, Main Development Region, and global average temperature explain the observations best. The most extreme events are especially sensitive to temperature changes, and we estimate a doubling of Katrina magnitude events associated with the warming over the 20th century. The increased risk depends on the spatial distribution of the temperature rise with highest sensitivity from tropical Atlantic, Central America, and the Indian Ocean. Statistically downscaling 21st century warming patterns from six climate models results in a twofold to sevenfold increase in the frequency of Katrina magnitude events for a 1 °C rise in global temperature (using BNU-ESM, BCC-CSM-1.1, CanESM2, HadGEM2-ES, INM-CM4, and NorESM1-M). PMID:23509254

  10. Monitoring pavement condition using Smart Dust under surge time synchronization

    NASA Astrophysics Data System (ADS)

    Pei, Jin-Song; Ivey, Richard A.; Lin, Hungjr; Landrum, Aaron; Sandburg, Colby J.; King, Timothy; Zaman, Musharraf M.; Refai, Hazem H.; Mai, Eric C.; Oshlake, Olatunda; Heriba, Adam; Hurt, Erin

    2007-04-01

    This paper is a continuation of the authors' previous effort (presented at SPIE 2006) of developing a "Smart Dust" (Mica2 Motes)-based wireless sensor network to detect hazardous roadway surface conditions. New developments reported herein focus on a series of investigations into the performance of "Smart Dust" wireless network. A series of pseudo-outdoor and road tests are conducted in this study. The network is fairly small with a large transmitting range between each Mote, compared with the published work on applying the same product. Surge Time Synchronization is explored in the specific application to allow each Mote to "wake up" periodically at a predefined time interval. In addition, a fairly simplistic pattern classification algorithm is embedded into the Motes to create the smart wireless sensing application. Many performance metrics of the adopted "Smart Dust" wireless sensor network with a small size and large transmitting range are revealed in this study through a series of data processing efforts. Results are presented to examine (1) network connectivity, (2) packet delivery performance, (3) initial connection time, (4) error rate, (5) battery life, and (6) other network routing properties such as the parent time histories for each Mote. These results and analysis form a database for future efforts to better understand the performance of and the collected results from "Smart Dust".

  11. Mapping dependence between extreme rainfall and storm surge across the Australian coastline using ROMS

    NASA Astrophysics Data System (ADS)

    Wu, Wenyan; Westra, Seth; Lenord, Michael; McInnes, Kathleen

    2017-04-01

    Storm surge caused by a combination of wind action and low pressure acting on the ocean's surface is a significant contributor to flooding in coastal and estuarine regions. When coincided with other flood-producing mechanisms such as extreme rainfall, the consequences can be devastating. Therefore it is important to understand the interaction between extreme storm surge and extreme rainfall. Previously, the dependence between extreme storm surge and extreme rainfall in Australia has been investigated using observed data from 49 tide gauges along the Australian coastline and statistically significant dependence has been observed for the majority of the locations (Zheng et al. 2013). However, in order to assess the flood risk due to coincident extreme surge and rainfall along coastal regions, more detailed mapping (e.g. including locations where there is no tide gauge) of the dependence between the two flood producing factors is required. There is also a need to quantify changes in dependence under climate change in order to understand future flood risk. Therefore, it is important to be able to quantify the dependence between extreme storm surge and extreme rainfall using modelled data. In this study, we investigated the dependence between extreme storm surge and extreme rainfall using modelled storm surge data from the Regional Ocean Modeling System (ROMS) (Shchepetkin and McWilliams 2005). Storm surge data from 551 locations along the Australian coastline (at 30 km intervals) between the 1st of January 1981 and the 7th of May 2013 were used. These locations were paired with daily rainfall from gauges within a 30 km radius. A bivariate logistic threshold-excess model was employed to quantify the dependence between extreme daily storm surge and extreme daily rainfall. The results were compared with dependence values calculated using observed storm surge at 79 tide gauges around Australia. Promising results were obtained. The dependence calculated using modelled storm

  12. Identification of Storm Surge Vulnerable Areas in the Philippines Through Simulations of Typhoon Haiyan-Induced Storm Surge Using Tracks of Historical Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    Lapidez, John Phillip; Suarez, John Kenneth; Tablazon, Judd; Dasallas, Lea; Gonzalo, Lia Anne; Santiago, Joy; Cabacaba, Krichi May; Ramos, Michael Marie Angelo; Mahar Francisco Lagmay, Alfredo; Malano, Vicente

    2014-05-01

    Super Typhoon Haiyan entered the Philippine Area of Responsibility (PAR) 07 November 2013, causing tremendous damage to infrastructure and loss of lives mainly due to the typhoon's storm surge and strong winds. Storm surges up to a height of 7 meters were reported in the hardest hit areas. The threat imposed by this kind of natural calamity compelled researchers of the Nationwide Operational Assessment of Hazards, the flagship disaster mitigation program of the Department of Science and Technology, Government of the Philippines, to undertake a study to determine the vulnerability of all Philippine coastal communities to storm surges of the same magnitude as those generated by Haiyan. This study calculates the maximum probable storm surge height for every coastal locality by running simulations of Haiyan-type conditions but with tracks of tropical cyclones that entered PAR from 1948-2013. DOST-Project NOAH used the Japan Meteorological Agency (JMA) Storm Surge Model, a numerical code that simulates and predicts storm surges spawned by tropical cyclones. Input parameters for the storm surge model include bathymetric data, storm track, central atmospheric pressure, and maximum wind speed. The simulations were made using Haiyan's pressure and wind speed as the forcing parameters. The simulated storm surge height values were added to the maximum tide level obtained from WXTide, software that contains a catalogue of worldwide astronomical tides, to come up with storm tide levels. The resulting water level was used as input to FLO-2D to generate the storm tide inundation maps. One product of this study is a list of the most vulnerable coastal areas that can be used as basis for choosing priority sites for further studies to implement appropriate site-specific solutions. Another product is the storm tide inundation maps that the local government units can use to develop a Risk-Sensitive Land Use Plan for identifying appropriate areas to build residential buildings

  13. More Research Shows Big Surge in U.S. Opioid Use, Addictions

    MedlinePlus

    ... Research Shows Big Surge in U.S. Opioid Use, Addictions Report from major insurer shows more than 20 ... Health News on Health Disparities Opioid Abuse and Addiction Recent Health News Related MedlinePlus Health Topics Health ...

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

    SciTech Connect

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

    2014-07-20

    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.

  15. Storm-induced semidiurnal perturbations to surges on the US Eastern Seaboard

    NASA Astrophysics Data System (ADS)

    Feng, Xi; Olabarrieta, Maitane; Valle-Levinson, Arnoldo

    2016-02-01

    Analysis of 19-year-long tidal gauge records along the US East Coast has revealed the appearance of semidiurnal perturbations to storm surges in the South Atlantic Bight. A total of 85 events with semidiurnal-surge amplitudes higher than 20% of the astronomic tidal amplitude and durations longer than two days were identified. These semidiurnal surge events were triggered by the passage of tropical storms and cold fronts. As a consequence of the storm-induced forcing, observed tides were delayed and partially damped with respect to the predictions. Such delay and damping resulted in a semidiurnal signal on the surge. Parallel-to-shore winds in the shelf region between Cape Hatteras and the South Atlantic Bight were highly correlated with the generation of the semidiurnal perturbations. Increased bottom friction combined with Coriolis acceleration, resulting from enhanced wind-driven alongshore currents, are proposed to be the primary factors delaying and attenuating astronomic tides.

  16. Effectiveness of zinc oxide surge arresters on substation equipment probabilities of flashover

    SciTech Connect

    Lambert, S.R. )

    1988-10-01

    Application of zinc oxide surge arresters has been increasingly considered as an effective means of limiting overvoltages. This paper addresses the effectiveness of such devices relative to the three phase probability of flashover of insulation systems.

  17. Departmental report on program EMTP-machine windings surge transients: Travelling wave method

    NASA Astrophysics Data System (ADS)

    Abdelrahman, M. H.

    The program may be used for the calculation of transient voltage distributions in machine windings caused by steep-fronted surges impinging upon the machine windings. The program uses a multi-conductor transmission line model to represent machine windings and is based on the traveling wave equations of a transmission line being an extension of the Lattice-Diagram Method due to Bewley. Whereas in two conductor transmission line calculations, the reflection and refraction coefficients at discontinuities are calculated from the simple line surge impedance of the sections on either side of the discontinuity for multi-conductor calculations, these individual surge impedances are replaced by surge impedance matrices which include the mutual effects between the conductors which make up the coil side.

  18. On the Storm Surge and Sea Level Rise Projections for Infrastructure Risk Analysis and Adaptation

    EPA Science Inventory

    Storm surge can cause coastal hydrology changes, flooding, water quality changes, and even inundation of low-lying terrain. Strong wave actions and disruptive winds can damage water infrastructure and other environmental assets (hazardous and solid waste management facilities, w...

  19. Development of Operational Wave-Tide-Storm surges Coupling Prediction System

    NASA Astrophysics Data System (ADS)

    You, S. H.; Park, S. W.; Kim, J. S.; Kim, K. L.

    2009-04-01

    The Korean Peninsula is surrounded by the Yellow Sea, East China Sea, and East Sea. This complex oceanographic system includes large tides in the Yellow Sea and seasonally varying monsoon and typhoon events. For Korea's coastal regions, floods caused by wave and storm surges are among the most serious threats. To predict more accurate wave and storm surges, the development of coupling wave-tide-storm surges prediction system is essential. For the time being, wave and storm surges predictions are still made separately in KMA (Korea Meteorological Administration) and most operational institute. However, many researchers have emphasized the effects of tides and storm surges on wind waves and recommended further investigations into the effects of wave-tide-storm surges interactions and coupling module. In Korea, especially, tidal height and current give a great effect on the wave prediction in the Yellow sea where is very high tide and related research is not enough. At present, KMA has operated the wave (RWAM : Regional Wave Model) and storm surges/tide prediction system (STORM : Storm Surges/Tide Operational Model) for ocean forecasting. The RWAM is WAVEWATCH III which is a third generation wave model developed by Tolman (1989). The STORM is based on POM (Princeton Ocean Model, Blumberg and Mellor, 1987). The RWAM and STORM cover the northwestern Pacific Ocean from 115°E to 150°E and from 20°N to 52°N. The horizontal grid intervals are 1/12° in both latitudinal and longitudinal directions. These two operational models are coupled to simulate wave heights for typhoon case. The sea level and current simulated by storm surge model are used for the input of wave model with 3 hour interval. The coupling simulation between wave and storm surge model carried out for Typhoon Nabi (0514), Shanshan(0613) and Nari (0711) which were effected on Korea directly. We simulated significant wave height simulated by wave model and coupling model and compared difference between

  20. Evaluation of Ferrite Chip Beads as Surge Current Limiters in Circuits with Tantalum Capacitors

    NASA Technical Reports Server (NTRS)

    Teverovsky, Alexander

    2014-01-01

    Limiting resistors are currently required to be connected in series with tantalum capacitors to reduce the risk of surge current failures. However, application of limiting resistors decreases substantially the efficiency of the power supply systems. An ideal surge current limiting device should have a negligible resistance for DC currents and high resistance at frequencies corresponding to transients in tantalum capacitors. This work evaluates the possibility of using chip ferrite beads (FB) as such devices. Twelve types of small size FBs from three manufacturers were used to evaluate their robustness under soldering stresses and at high surge current spikes associated with transients in tantalum capacitors. Results show that FBs are capable to withstand current pulses that are substantially greater than the specified current limits. However, due to a sharp decrease of impedance with current, FBs do not reduce surge currents to the required level that can be achieved with regular resistors.

  1. U.S. Pedestrian Deaths Surged to Record Levels in 2016

    MedlinePlus

    ... medlineplus.gov/news/fullstory_164371.html U.S. Pedestrian Deaths Surged to Record Levels in 2016 Experts point ... News) -- For the second straight year, U.S. pedestrian deaths are setting alarming new records. The number of ...

  2. On the Storm Surge and Sea Level Rise Projections for Infrastructure Risk Analysis and Adaptation

    EPA Science Inventory

    Storm surge can cause coastal hydrology changes, flooding, water quality changes, and even inundation of low-lying terrain. Strong wave actions and disruptive winds can damage water infrastructure and other environmental assets (hazardous and solid waste management facilities, w...

  3. On the 'real' mass loss of some surging glaciers in the central Karakoram

    NASA Astrophysics Data System (ADS)

    Paul, Frank

    2016-04-01

    Several assessments of the mass changes of surging glaciers in the central Karakoram (and elsewhere) have shown near-zero changes over the typically decadal-long observation periods. This is in line with the theory that during a surge mass from a reservoir area is moved down-glacier to a receiving area with limited overall change. The resulting elevation changes of the glacier surface as determined by differencing DEMs from two points in time show a typical pattern (decreasing at higher, increasing at lower elevations) with a possible strong frontal advance (km scale) of the terminus. However, this is only half of the story as the observed mass gain at lower elevations is ultimately also a loss. This loss can only be determined when it is calculated separately and when sufficiently precise DEMs from the beginning and the end of a surge are available for each individual glacier. As the latter are hard to obtain, this study presents a simplified geomorphometric approach to approximate a potential maximum surge volume for 20 glaciers with a channel-like glacier fore field. By assuming a semi-elliptical cross-section of the channels, simple measurements of their average width, height and length in Google Earth provide the volume. Further glacier-specific parameters are taken from a recently compiled glacier inventory (area, slope) and Google Earth (minimum length and highest/lowest elevations) to obtain characteristics such as elevation ranges and volume. The average annual specific volume loss for each glacier is then determined by dividing the calculated surge volumes by the respective glacier area and the duration of a full surge cycle (obtained in a previous study). Which glacier area (minimum?) and surge duration (only the active phase?) have to be taken for this calculation is likely a matter of debate. With surge distances between about 1 and 5 km and channel widths (heights) between 300 and 700 (50 and 125) m, the surge volumes vary between 15 and 250 (mean 80

  4. Global reconstructed daily storm surge levels from the 20th century reanalysis (1871-2010)

    NASA Astrophysics Data System (ADS)

    Cid, Alba; Camus, Paula; Castanedo, Sonia; Mendez, Fernando; Medina, Raul

    2015-04-01

    The study of global patterns of wind and pressure gradients, and more specifically, their effect on the sea level variation (storm surge), is a key issue in the understanding of recent climate changes. The local effect of storm surges on coastal areas (zones particularly vulnerable to climate variability and changes in sea level), is also of great interest in, for instance, flooding risk assessment. Studying the spatial and temporal variability of storm surges from observations is a difficult task to accomplish since observations are not homogeneous in time and scarce in space, and moreover, their temporal coverage is limited. The development of a global storm surge database (DAC, Dynamic Atmospheric Correction by Aviso, Carrère and Lyard, 2003) fulfils the lack of data in terms of spatial coverage, but not regarding time extent since it only includes last couple of decades (1992-2014). In this work, we propose the use of the 20CR ensemble (Compo et al., 2011) which spans from 1871 to 2010 to statistically reconstruct storm surge at a global scale and for a long period of time. Therefore, the temporal and spatial variability of storm surges can be fully studied and with much less effort than performing a dynamical downscaling. The statistical method chosen to carry out the reconstruction is based on multiple linear regression between an atmospheric predictor and the storm surge level at daily scale (Camus et al., 2014). The linear regression model is calibrated and validated using daily mean sea level pressure fields (and gradients) from the ERA-interim reanalysis and daily maxima surges from DAC. The obtained daily database of maximum daily surges has allowed us to estimate global trends at a centennial scale and analyse the effect of the changing climate on storm surges during the 20th century. Hence, this work improves the knowledge on historical storm-surge conditions and provides helpful information to the community concern on marine climate evolution and

  5. Determining the Return Period of Storm Surge Events in the Philippines

    NASA Astrophysics Data System (ADS)

    Santiago, Joy; Suarez, John Kenneth; Lapidez, John Phillip; Mendoza, Jerico; Caro, Carl Vincent; Tablazon, Judd; Ladiero, Christine; Mahar Francisco Lagmay, Alfredo

    2015-04-01

    The devastating damages generated by the Tropical Cyclone Haiyan storm surges in Eastern Samar, Philippines prompted the Department of Science and Technology-Project NOAH (Nationwide Operational Assessment of Hazards) to calculate the return period and storm surge exceedance probability of these events. The recurrence interval or the period of return of a storm surge event is the estimated likelihood that that event would occur again. Return periods are measured through historical data denoting the interval of recurrence in average over a period of time. The exceedance probability however, is a graphical representation that describes the probability that some various levels of loss will be exceeded over a future time period or will be surpassed over a given time. DOST-Project NOAH simulates storm surge height time series using JMA storm surge model which is a numerical model based on shallow water equations. To determine the period of recurrence of storm surges with this type of intensity, the agency intends to compute the estimation of storm surge heights generated by tropical cyclones for 2-year, 5-year, 10-year, 25-year, 50-year and 100-year return periods for the Philippine coast. The storm surge time series generated from JMA combined with WXTide simulation, a software containing archives/catalogues of world-wide astronomical tides, and 5-meter resolution DEM were used as input parameters for the inundation model, which shows probable extent of flooding at a specific storm surge return period. Flo-2D two-dimensional flood routing model, a GIS integrated software tool that facilitates the creation of the flood model grid system, was used for flood hazard model. It is a simple volume conservation model composed of processor program that facilitate graphical editing and mapping of flooding details which uses continuity equation and the dynamic wave momentum equations. The measurements of storm surge return period and probable extent of coastal flooding in the

  6. Comparisons of hurricane-induced storm surge models and their operational use

    NASA Astrophysics Data System (ADS)

    Choi, J.; Gay, P.; Rigney, J. P.; Doody, M.

    2010-12-01

    The most devastating hazard to human life, habitat and property associated with hurricanes is due to storm surge. The US Navy is often called upon to render humanitarian assistance and aid in disaster recovery in the wake of storm surge events. It is imperative, therefore, that the US Navy, as well as other agencies responsible for national security and safeguarding life and property, evaluate the options available for improvements to operational modeling capabilities. Improvement of storm surge forecast skill has advanced significantly during the past couple of decades as a result of finer resolution, more robust physics, and the inclusion of wave setup and wave-current interaction. Current storm surge models used by United States government agencies, the SLOSH model used by the National Hurricane Center, PCTides by the Naval Oceanographic Office (NAVOCEANO), and ADCIRC by the US Army Corps of Engineers, have several drawbacks such as neglect of tides, wave effects, and insufficient spatial resolution. The purpose of this study is to evaluate and compare available hurricane-induced storm surge models in order to inform the selection of the optimal storm surge model for operational use at NAVOCEANO. This will involve investigation of operational capability and forecast skill of SLOSH, PCTides and ADCIRC, as well as several other storm surge models including CH3D-SSMS, Delft3D and FVCOM. The initial phase, presented in this poster, will entail a literature review to determine and summarize the recent and current state of storm-surge model comparisons in the scientific, industry, and government communities. Consideration will be given to the relative importance of improved inputs to the models (wind-fields and storm track/intensity and associated hurricane prediction models) as compared with model selection.

  7. Development of An Unstructured Storm Surge-waves-tide Coupled Model And Its Application

    NASA Astrophysics Data System (ADS)

    Feng, X.

    2015-12-01

    An unstructured storm surge-waves-tide coupled model, which was coupled through the Model Coupling Toolkit (MCT), was developed based on the ADCIRC (Advanced Circulation model) ocean model and SWAN (Simulating Waves Nearshore) wave model. The developed coupled model has high resolution in the coast area and can be run efficiently. By comparing with the existing ADCIRC and SWAN coupled model, which was coupled directly not through the MCT, the newly developed one can increase the simulation efficiency by 26.4 percent, when the computational grid and coupling processes of the two coupled model were the same. The coupled model was used to simulate the storm surge and waves during the process of typhoon "Usagi" which formed in the western Pacific on September 17, 2013 and made landfall at Shanwei in Guangdong province. Three numerical experiments were done in the simulation to study the effect of wave-current interaction on the storm surge and waves. Results show that the coupled model can simulate the storm surge and waves well when considering the wave induced radiation stress, the wave effect on the wind stress drag coefficient and the modulation of current and water level on the waves. During the process of typhoon "Usagi" the effect of wave radiation stress can result in a maximum of 0.75m increase in the extreme storm surge, and the wave induced wind stress can cause a -0.82~0.49m change of the extreme storm surge near the coastal area. This study is valuable to the study of hurricane storm surge disaster assessment and the development of the operational storm surge prediction technique.

  8. A model of the Glaciar Horcones Inferior surge, Aconcagua region, Argentina

    NASA Astrophysics Data System (ADS)

    Milana, Juan Pablo

    The deformation, resulting from a surge in 1985, of Glaciar Horcones Inferior is analyzed using structural geological models. During the surge, previously continuous debris cover was deformed by the formation of regularly separated and rotated ice blocks, suggesting a system of linked rotational extensional faults. Block tilting was measured from photographs taken shortly after the surge, showing rotation of the debris-covered surface. Fault inclination was assumed to be coincident with the debris-free side of the block. Glacier advance during the surge was obtained by comparing pre-surge aerial photographs with the position of maximum advance after the surge. Glacier thinning was estimated from the debris surface average lowering (relief generated at lateral scarps coincident with shear zones) and ice thickness measurements after surge termination. Three independent sets of information, geometry of the deformation (i.e. depth of detachment, fault traces, fault spacing, block rotation), glacier thinning and net advance, limit possible interpretations. Surface geometry suggests a domino-style or a linked planar rotational extensional fault system. In the observed configuration, however, these models can only explain a 12-13% extension. Glacier thinning suggests 30% local extension, and total glacier advance implies 16% minimum extension, which does not account for some frontal compression, as observed. A linked curved rotational extensional fault model fits the data well, implying a significant degree of internal deformation within each block. This model satisfactorily explains the observed deformation produced by the surge. It may also explain some modes of fast glacier flow, since the observed style of block tilting is present in other glaciers with high relief.

  9. An Analysis of Air Force Systems Command’s Industrial Surge Preparedness Planning.

    DTIC Science & Technology

    1987-09-01

    have you taken related to suroe preparedness planning? Only three participants stated that they had taken the * basic production management courses AFIT...program phase was/(will) surge planning initially (be) put on contract? a. Suroe not applicable b. Concept Exploration c. Demonstration/Validation d...constantly. (2) Bad answers - Surge is problem in avionics only if suroes requires more test equipment to build upon to suroe rate. 7 esl equipment at least

  10. Role of wetlands in attenuation of storm surges using coastal circulation model (ADCIRC), Chesapeake Bay region

    NASA Astrophysics Data System (ADS)

    Deb, Mithun; Ferreira, Celso; Lawler, Seth

    2014-05-01

    The Chesapeake Bay, Virginia is subject to storm surge from extreme weather events nearly year-round; from tropical storms and hurricanes during the summer and fall, (e.g., hurricanes Isabel [2003] and Sandy [2012]), and from nor'easters during the winter (e.g., winter storms Nemo and Saturn [2013]). Coastal wetlands can deliver acute fortification against incoming hurricane storm surges. Coastal wetlands and vegetation shape the hydrodynamics of storm surge events by retaining water and slowing the propagation of storm surge, acting as a natural barrier to flooding. Consequently, a precise scheme to quantify the effect of wetlands on coastal surge levels was also prerequisite. Two wetland sites were chosen in the Chesapeake Bay region for detailed cataloging of vegetation characteristics, including: height, stem diameter, and density. A framework was developed combining these wetlands characterizations with numerical simulations. Storms surges were calculated using Coastal circulation model (ADCIRC) coupled to a wave model (SWAN) forced by an asymmetric hurricane vortex model using an unstructured mesh (comprised of 1.8 million nodes) under a High Performance Computing environment. The Hurricane Boundary Layer (HBL) model was used to compute wind and pressure fields for historical tropical storms and for all of the synthetic storms. Wetlands were characterized in the coupled numerical models by bathymetric and frictional resistance. Multiple model simulations were performed using historical hurricane data and hypothetical storms to compare the predicted storm surge inundation resulting from various levels of wetlands expansion or reduction. The results of these simulations demonstrate the efficacy of wetlands in storm surge attenuation and also the outcome will scientifically support planning of wetlands restoration projects with multi-objective benefits for society.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  13. Europa's Opposition Surge in the Near-Infrared: Interpreting Disk-Integrated Observations by Cassini VIMS

    NASA Astrophysics Data System (ADS)

    Simonelli, D. P.; Buratti, B. J.

    2003-05-01

    Observations of Europa's opposition surge by Cassini VIMS, presented at last year's DPS, have now been modeled with the commonly used Hapke photometric function. The VIMS dataset emphasizes observations at 16 phase angles from 0.4 to 0.6 deg---the first time the < 1 deg phase ``heart" of Europa's opposition surge has been observed in the near-IR. This dataset also provides a unique opportunity to examine how the surge is affected by changes in wavelength and albedo: at VIMS wavelengths of 0.91, 1.73, and 2.25 microns, the geometric albedo of Europa is 0.81, 0.33, and 0.18 respectively. Despite this factor-of-four albedo range, however, the slope of Europa's phase curve at < 1 deg phase is similar at all three wavelengths (to within error bars) and this common slope is similar to the phase coefficient seen in visible observations of Europa. Two competing models for the opposition surge's physical cause are the Shadow Hiding Opposition Effect (SHOE) and Coherent Backscatter Effect (COBE). Because of sparse VIMS phase coverage, it's not possible to constrain all the surge parameters at once in a Hapke function that has both SHOE and COBE; accordingly, we performed separate Hapke fits for SHOE-only and COBE-only surges. At 2.25 microns, where VIMS data are somewhat noisy, both types of surges can mimic the slope of the VIMS phase curve at < 1 deg phase. At 0.91 and 1.73 microns, however---where VIMS data are ``cleaner"---COBE does a noticeably poorer job than SHOE of matching the VIMS phase coefficient at < 1 deg phase; in particular, the best COBE fit insists on having a steeper phase-curve slope than the data. This suggests---without being conclusive---that COBE is less likely than SHOE to be the cause of Europa's near-IR opposition surge.

  14. A time series of TanDEM-X digital elevation models to monitor a glacier surge

    NASA Astrophysics Data System (ADS)

    Wendt, Anja; Mayer, Christoph; Lambrecht, Astrid; Floricioiu, Dana

    2016-04-01

    Bivachny Glacier, a tributary of the more than 70 km long Fedchenko Glacier in the Pamir Mountains, Central Asia, is a surge-type glacier with three known surges during the 20th century. In 2011, the most recent surge started which, in contrast to the previous ones, evolved down the whole glacier and reached the confluence with Fedchenko Glacier. Spatial and temporal glacier volume changes can be derived from high-resolution digital elevation models (DEMs) based on bistatic InSAR data from the TanDEM-X mission. There are nine DEMs available between 2011 and 2015 covering the entire surge period in time steps from few months up to one year. During the surge, the glacier surface elevation increased by up to 130 m in the lower part of the glacier; and change rates of up to 0.6 m per day were observed. The surface height dataset was complemented with glacier surface velocity information from TerraSAR-X/ TanDEM-X data as well as optical Landsat imagery. While the glacier was practically stagnant in 2000 after the end of the previous surge in the 1990s, the velocity increase started in 2011 in the upper reaches of the ablation area and successively moved downwards and intensified, reaching up to 4.0 m per day. The combination of surface elevation changes and glacier velocities, both of high temporal and spatial resolution, provides the unique opportunity to describe and analyse the evolution of the surge in unprecedented detail. Especially the relation between the mobilization front and the local mass transport provides insight into the surge dynamics.

  15. Reference Model 5 (RM5): Oscillating Surge Wave Energy Converter

    SciTech Connect

    Yu, Y. H.; Jenne, D. S.; Thresher, R.; Copping, A.; Geerlofs, S.; Hanna, L. A.

    2015-01-01

    This report is an addendum to SAND2013-9040: Methodology for Design and Economic Analysis of Marine Energy Conversion (MEC) Technologies. This report describes an Oscillating Water Column Wave Energy Converter (OSWEC) reference model design in a complementary manner to Reference Models 1-4 contained in the above report. A conceptual design for a taut moored oscillating surge wave energy converter was developed. The design had an annual electrical power of 108 kilowatts (kW), rated power of 360 kW, and intended deployment at water depths between 50 m and 100 m. The study includes structural analysis, power output estimation, a hydraulic power conversion chain system, and mooring designs. The results were used to estimate device capital cost and annual operation and maintenance costs. The device performance and costs were used for the economic analysis, following the methodology presented in SAND2013-9040 that included costs for designing, manufacturing, deploying, and operating commercial-scale MEC arrays up to 100 devices. The levelized cost of energy estimated for the Reference Model 5 OSWEC, presented in this report, was for a single device and arrays of 10, 50, and 100 units, and it enabled the economic analysis to account for cost reductions associated with economies of scale. The baseline commercial levelized cost of energy estimate for the Reference Model 5 device in an array comprised of 10 units is $1.44/kilowatt-hour (kWh), and the value drops to approximately $0.69/kWh for an array of 100 units.

  16. Discovery of a Remarkable Opposition Surge on Triton

    NASA Astrophysics Data System (ADS)

    Buratti, B. J.; Bauer, J.; Hicks, M.; Herbert, B.; Schmidt, B.; Cobb, B.; Ward, J.

    2006-05-01

    The large Neptunian satellite Triton is one of three moons in the outer Solar System that exhibit volcanism. Triton's volcanoes appear to be driven by solar heating. In addition, significant seasonal volatile is expected to occur on Triton. To understand the nature and extent of activity on Triton, including volcanism and seasonal volatile transport, we have undertaken a program of deriving the surface properties of Triton through time by means of ground- based observations. Another motivation for our work is to closely study a body that may bear a strong resemblance to the planet Pluto and the swarm of icy bodies in the outer Solar System now known as Kuiper Belt Objects. One important measurement is the solar phase curve, or the brightness as a function of the angle between the observer, the object being observed, and the sun. Most significant are observations at large solar phase angles, which probe the roughness of the surface, and small angles, which characterize the fluffiness of the surface and give clues to optical phenomena such as coherent backscatter. For Triton, large phase angles are not observable from Earth, but the 2004 season presented an opportunity in which the solar phase angle reached the exceedingly low value of 0.002 degrees. During the 2004 season, photometric observations of Triton's phase curve were obtained in the astronomical BVRI filters, spanning wavelengths from 0.45 to 0.89 microns. Triton exhibits a large increase in its brightness as the solar phase angle approaches zero. There is a wavelength dependence to this opposition surge, the term commonly used to describe the non-linear increase in brightness observed on almost all airless bodies.

  17. Lightning as a Detector of Convective Surges in Thunderstorms

    NASA Astrophysics Data System (ADS)

    Hamlin, T.; Harlin, J. D.; Krehbiel, P. R.; Rison, W.; Thomas, R. J.

    2001-12-01

    New Mexico Tech's 3-dimensional lightning mapping system (LMA) was operated in support of the Severe Thunderstorm Electrification and Precipitation Study (STEPS) from late May to early August 2000. Previous LMA studies discovered occasions where high-altitude radiation sources were frequently observed above convective thunderstorms. These observations represented a lightning phenomena which had not been observed prior to the advent of the LMA. The events consisted of frequent, localized, short-duration discharges and appeared to occur continuously and independently of other lightning activity in the lower regions of the storm. Indications were that the events happen within (or possibly above) overshooting tops associated with strong convective bursts in thunderstorms. On June 29, 2000 during STEPS, the LMA recorded a storm which produced an F1 tornado. Prior to tornado formation there were three periods where lightning sources rose above the main discharge regions of the storm. During these occasions of enhanced high-altitude activity, lightning free holes formed in the central region of the cell, indicating that the events correlate with overshooting convective tops. Several other convective bursts occurred in rapid succession after the third, and an F1 tornado formed. Following the tornado, the storm continued to show strong convective surges as well as an overall increase in height of lightning activity. In this paper we discuss case studies where a height versus time display, over the active lifetime of a storm, demonstrates similar behavior. When the data is displayed over a large time range the epochs of enhanced high-altitude discharges are very clear, and indicate an increase in storm intensity and severity.

  18. Linkage of Rainfall-Runoff and Hurricane Storm Surge in Galveston Bay

    NASA Astrophysics Data System (ADS)

    Deitz, R.; Christian, J.; Wright, G.; Fang, N.; Bedient, P.

    2012-12-01

    In conjunction with the SSPEED Center, large rainfall events in the upper Gulf of Mexico are being studied in an effort to help design a surge gate to protect the Houston Ship Channel during hurricane events. The ship channel is the world's second largest petrochemical complex and the Coast Guard estimates that a one-month closure would have a $60 billion dollar impact on the national economy. In this effort, statistical design storms, such as the 24-hour PMP, as well as historical storms, like Hurricane Ike, Hurricane Katrina, and Hurricane Rita, are being simulated in a hydrologic/hydraulic model using radar and rain gauge data. VfloTM, a distributed hydrologic model, is being used to quantify the effect that storm size, intensity, and location has on timing and peak flows in the in the upper drainage area. These hydrographs were input to a hydraulic model with various storm surges from Galveston Bay. Results indicate that there is a double peak phenomenon with flows from the west draining days earlier than flows from the north. With storm surge typically lasting 36-48 hours, this indicates the flows from the west are interacting with the storm surge, whereas flows from the north would arrive once the storm surge is receding. Gate operations were optimized in the model to account for the relative timing of upland runoff and hurricane surge, and to quantify the capability of the gate structure to protect the Ship Channel industry.

  19. On using scatterometer and altimeter data to improve storm surge forecasting in the Adriatic Sea

    NASA Astrophysics Data System (ADS)

    Bajo, Marco; Umgiesser, Georg; De Biasio, Francesco; Vignudelli, Stefano; Zecchetto, Stefano

    2017-04-01

    Satellite data are seldom used in storm surge forecasting. Among the most important issues related to the storm surge forecasting are the quality of the model wind forcing and the initial condition of the sea surface elevation. In this work, focused on storm surge forecasting in the Adriatic Sea, satellite scatterometer wind data are used to correct the wind speed and direction biases of the ECMWF global atmospheric model by tuning the spatial fields, as an alternative to data assimilation. The capability of such an unbiased wind is tested against that of a high resolution wind, produced by a regional non-hydrostatic model. On the other hand, altimeter Total Water Level Envelope (TWLE) data, which provide the sea level elevation, are used to improve the accuracy of the initial state of the model simulations. This is done by assimilating into a storm surge model the TWLE obtained by the altimeter observations along ground tracks, after subtraction of the tidal components. In order to test the methodology, eleven storm surge events recorded in Venice, from 2008 to 2012, have been simulated using different configurations of forcing wind and altimeter data assimilation. Results show that the relative error on the estimation of the maximum surge peak, averaged over the cases considered, decreases from 13% to 7% using both the unbiased wind and the altimeter data assimilation, while forcing the hydrodynamic model with the high resolution wind (no tuning), the altimeter data assimilation reduces the error from 9% to 6%.

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

    USGS Publications Warehouse

    Kress, Michael E.; Benimoff, Alan I.; Fritz, William J.; Thatcher, Cindy; 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.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2017-05-01

    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.

  3. DOT tomography of the solar atmosphere. V. Analysis of a surge from AR10486

    NASA Astrophysics Data System (ADS)

    Tziotziou, K.; Tsiropoula, G.; Sütterlin, P.

    2005-12-01

    We present an analysis of high temporal and spatial resolution CaII H chromospheric limb observations obtained with the Dutch Open Telescope (DOT). We focus on a solar surge observed both by the DOT in CaII H and the Transition Region and Coronal Explorer (TRACE) satellite in the 195 Å and 1600 Å passbands. The surge is observed in active region AR10486 located near the solar limb, a region which two hours later produced the largest X-flare ever recorded. It consists of relatively cold gas of about 104-105 K. In TRACE images the surge is followed for almost 2.5 h, shrinking and expanding at the same location several times. From DOT images we find outward propagating intensity disturbances, with velocities higher than 50 km s-1, indicative of upward material motion. The latter is also suggested by the good correlation between the DOT and TRACE surge apparent height curves, their apparent time delay and a phase difference analysis. A spectral wavelet analysis of the brightness variations within and along the surge shows a predominant period of ~6 min, the first ever reported for this kind of structures. Magnetic reconnection at the bottom of the surge as its driving mechanism is suggested by the observed inverted "Y" shape configuration and is further supported by a phase difference analysis.

  4. Surge Pressure Mitigation in the Global Precipitation Measurement Mission Core Propulsion System

    NASA Technical Reports Server (NTRS)

    Scroggins, Ashley R.; Fiebig, Mark D.

    2014-01-01

    The Global Precipitation Measurement (GPM) mission is an international partnership between NASA and JAXA whose Core spacecraft performs cutting-edge measurements of rainfall and snowfall worldwide and unifies data gathered by a network of precipitation measurement satellites. The Core spacecraft's propulsion system is a blowdown monopropellant system with an initial hydrazine load of 545 kg in a single composite overwrapped propellant tank. At launch, the propulsion system contained propellant in the tank and manifold tubes upstream of the latch valves, with low-pressure helium gas in the manifold tubes downstream of the latch valves. The system had a relatively high beginning-of- life pressure and long downstream manifold lines; these factors created conditions that were conducive to high surge pressures. This paper discusses the GPM project's approach to surge mitigation in the propulsion system design. The paper describes the surge testing program and results, with discussions of specific difficulties encountered. Based on the results of surge testing and pressure drop analyses, a unique configuration of cavitating venturis was chosen to mitigate surge while minimizing pressure losses during thruster maneuvers. This paper concludes with a discussion of overall lessons learned with surge pressure testing for NASA Goddard spacecraft programs.

  5. Morning blood pressure surge and arterial stiffness in newly diagnosed hypertensive patients.

    PubMed

    Kıvrak, Ali; Özbiçer, Süleyman; Kalkan, Gülhan Yüksel; Gür, Mustafa

    2017-06-01

    We aimed to investigate the relationship between the morning blood pressure (BP) surge and arterial stiffness in patients with newly diagnosed hypertension. Three hundred and twenty four (mean age 51.7 ± 11.4 years) patients who had newly diagnosed hypertension with 24 h ambulatory BP monitoring were enrolled. Parameters of arterial stiffness, pulse wave velocity and augmentation index (Aix) were measured by applanation tonometry and aortic distensibility was calculated by echocardiography. Compared with the other groups, pulse wave velocity, day-night systolic BP (SBP) difference (p < 0.001, for all) and hs-CRP (p = 0.005) were higher in morning BP surge high group. Aortic distensibility values were significantly lower in morning BP surge high group compared to the other groups (p < 0.05, for all). Morning BP surge was found to be independently associated with pulse wave velocity (β = 0.286, p < 0.001), aortic distensibility (β= -0.384, p < 0.001) and day-night SBP difference (β = 0.229, p < 0.001) in multivariate linear regression analysis. We found independent relationship between morning BP surge and arterial stiffness which is a surrogate endpoint for cardiovascular diseases. The inverse relationship between morning BP surge and aortic distensibility and direct relation found in our study is new to the literature.

  6. Relationships between Gulf of California Moisture Surges and Precipitation in the Southwestern United States.

    NASA Astrophysics Data System (ADS)

    Higgins, R. W.; Shi, W.; Hain, C.

    2004-08-01

    Relationships between Gulf of California moisture surges and precipitation in the southwestern United States are examined. Standard surface observations are used to identify gulf surge events at Yuma, Arizona, for a multiyear (July August of 1977 2001) period, and Climate Prediction Center (CPC) precipitation analyses and NCEP NCAR reanalysis data are used to relate the gulf surge events to the precipitation and atmospheric circulation patterns, respectively. Emphasis is placed on the relative differences in the precipitation and atmospheric circulation patterns for several categories of surge events, including those that are relatively strong (weak) and those that are accompanied by relatively wet (dry) conditions in Arizona and New Mexico after onset. It is shown that rapid surface dewpoint temperature increases are not necessarily a good indicator of increased rainfall in the region.The extent to which the precipitation and atmospheric circulation patterns are influenced by a phasing of tropical easterly and midlatitude westerly waves is also considered. Results indicate that a significant fraction of the events in all categories are related to the passage of westward-propagating tropical easterly waves across western Mexico. However, the occurrence of wet versus dry surges in the southwestern United States is not discriminated by the presence of tropical easterly waves, but rather by the relative location of the upper-level anticyclone in midlatitudes at the time of the gulf surge.


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

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

    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 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 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 to obtain storm surge level maps that can be of major interest for coastal planners and decision makers in terms of risk management.

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

    NASA Astrophysics Data System (ADS)

    Munroe, Robert; Curtis, Scott

    2016-03-01

    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.

  9. The Value of Wetlands in Protecting Southeast Louisiana from Hurricane Storm Surges

    PubMed Central

    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. PMID:23536815

  10. Cortisol interferes with the estradiol-induced surge of luteinizing hormone in the ewe.

    PubMed

    Wagenmaker, Elizabeth R; Breen, Kellie M; Oakley, Amy E; Pierce, Bree N; Tilbrook, Alan J; Turner, Anne I; Karsch, Fred J

    2009-03-01

    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 approximately 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.

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

    NASA Astrophysics Data System (ADS)

    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.

  12. Annual bed statistics give a misleading picture of hospital surge capacity.

    PubMed

    DeLia, Derek

    2006-10-01

    I describe how annual hospital surge capacity is affected by within-year variation in patient volume and bed supply. Surge capacity was measured as the percentage and total number of hospital beds that are not occupied by patients. Administrative data were used to calculate these bed statistics for 78 hospitals in New Jersey--statewide and by emergency planning regions--in 2003. Annual bed statistics were compared to more refined calculations for each day of the year. Calculated numbers of empty beds were compared to federal disaster planning benchmarks. Annual bed statistics showed no major limitations on surge capacity. Statewide occupancy rates were well below 80% (ie, more than 20% of beds were empty), and the number of empty beds that were set up and staffed (ie, maintained) was well above federal disaster planning benchmarks. In contrast, daily bed statistics reveal long periods in 2003 when regional and statewide surge capacity was severely strained. Strained capacity was most likely to occur on Tuesdays through Fridays and least likely to occur on weekends. On 212 days, statewide occupancy of maintained beds met or exceeded 85%. This occupancy rate met or exceeded 90% and 95% on 88 and 4 days, respectively. On 288 days, the statewide number of empty maintained beds fell below the federal planning benchmark. Annual bed statistics give a misleading picture of hospital surge capacity. Analysis of surge capacity should account for daily variation in patient volume and within-year variation in bed supply.

  13. Impact of using scatterometer and altimeter data on storm surge forecasting

    NASA Astrophysics Data System (ADS)

    Bajo, Marco; De Biasio, Francesco; Umgiesser, Georg; Vignudelli, Stefano; Zecchetto, Stefano

    2017-05-01

    Satellite data are rarely used in storm surge models because of the lack of established methodologies. Nevertheless, they can provide useful information on surface wind and sea level, which can potentially improve the forecast. In this paper satellite wind data are used to correct the bias of wind originating from a global atmospheric model, while satellite sea level data are used to improve the initial conditions of the model simulations. In a first step, the capability of global winds (biased and unbiased) to adequately force a storm surge model are assessed against that of a high resolution local wind. Then, the added value of direct assimilation of satellite altimeter data in the storm surge model is tested. Eleven storm surge events, recorded in Venice from 2008 to 2012, are simulated using different configurations of wind forcing and altimeter data assimilation. Focusing on the maximum surge peak, results show that the relative error, averaged over the eleven cases considered, decreases from 13% to 7%, using both the unbiased wind and assimilating the altimeter data, while, if the high resolution local wind is used to force the hydrodynamic model, the altimeter data assimilation reduces the error from 9% to 6%. Yet, the overall capabilities in reproducing the surge in the first day of forecast, measured by the correlation and by the rms error, improve only with the use of the unbiased global wind and not with the use of high resolution local wind and altimeter data assimilation.

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

    PubMed

    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.

  15. Distribution Surge Arrester Failures due to Winter Lightning and Measurement of Energy Absorption Capability of Arresters

    NASA Astrophysics Data System (ADS)

    Sugimoto, Hitoshi; Shimasaki, Katsuhiko; Kado, Hiroyuki

    Surge arresters and distribution equipments with zinc-oxide elements are used for lightning protection of overhead power distribution lines in Japan. However, these surge arresters are sometimes damaged by direct lightning strokes, especially in winter. Increasing of surge arrester failures in winter is attributed to a very large electric charge of winter lightning than that of summer lightning. For improvement of surge arresters, we have measured the energy absorption capability of surge arresters using a half cycle of alternating current with a frequency of 50Hz for simulating a winter lightning current. The mean values of arrester failure energy increased in proportion to the volume of zinc-oxide element, however the values of arrester failure energy were quite uneven. We also have observed the aspects of damaged zinc-oxide elements, and have investigated the relationship between the arrester failure energy and the failure types of zinc-oxide elements. From these results, we suggest the improvement of the energy absorption capability of distribution surge arresters, especially for the uniform energy absorption capability.

  16. The Influence of Hurricane Parameters on Hurricane Surge and Waves in Complex Coastal Zones

    NASA Astrophysics Data System (ADS)

    Udoh, I. E.; Taylor, A.; Irish, J. L.; Kaihatu, J. M.

    2012-12-01

    Studies on the impact of potential flooding in complex coastal regions, such as coastal bays, require efficient models for the estimation of surge and waves under various hurricane meteorological scenarios. Recently, surrogate models for high resolution numerical models have been successfully applied in extreme value flood studies (e.g. Resio et al. 2009; Niedoroda et al. 2008). Adequate identification of the primary parameters that drive the surge and wave trends, and physical understanding of the expected trends are important in developing non-dimensional equations which replicate the processes of surge and wave generation. Identified parameters can thus be used in developing scaling laws for the estimation of hurricane surge and wave response. In this study, we discuss surge and wave trends in Corpus Christi Bay, Texas as a function of meteorological and spatial parameters, and we isolate their influences on surge response. Changes in surge with hurricane forward speed in the bay is found to be primarily dependent on time available for surge development and re-distribution within the bay. The hurricane angle of approach affects surge generation based on the orientation of onshore-directed winds and the proximity of the storm track to the entrance of the bay and locations of interest. A positive linear trend is observed between sea level rise and storm surge in the bay - this is due to overtopping of the barrier island, and the fact that the irregular bay boundaries support surge accumulation. As a basis for investigating wave responses, hurricane parameters of central pressure and size were identified as main factors in characterizing the wave field. Results showed that with variation in the hurricane's central pressure and size, changes in wave heights are more pronounced in the nearshore and onshore environment at the open coast, than they are within the bay. Likewise, a similar spatial trend is observed in the variation of these hurricane parameters to

  17. Cold basal conditions during surges control flow of fringing Arctic ice caps in Greenland

    NASA Astrophysics Data System (ADS)

    Cook, Samuel; Christoffersen, Poul; Todd, Joe; Palmer, Steven

    2017-04-01

    Fringing ice caps separated from larger ice sheets are rarely studied, yet they are an important part of earth's cryosphere, which has become the largest source of global sea-level rise. Understanding marginal ice caps is crucial for being able to predict sea-level change as they are responsible for up to 20% of Greenland's mass loss for 2003-2008. Studies of fringing ice caps can furthermore provide useful insights into processes operating on glaciers that surge. Surging has been the focus of much recent glaciological work, especially with reference to thermal evolution of polythermal glaciers in High Mountain Asia and the High Arctic. This has shown that the classic divide between hydrologically-controlled surges ('hard-bed') in Alaska and thermally-regulated ('soft-bed') surges elsewhere is less stark than previously assumed. Studying marginal ice caps can therefore be valuable in several ways. The largest fringing ice cap in Greenland is Flade Isblink. Previous work has established that this ice cap is showing a range of dynamic behaviour, including subglacial lake drainage and varied patterns of mass-balance change. In particular, a substantial surge, assumed to be caused by a version of the thermally-regulated mechanism, occurred between 1996 and 2000, making the ice cap a useful case study for investigating this process. Here we investigate the surge on Flade Isblink using the open-source, Full-Stokes model Elmer/Ice to invert for basal conditions and englacial temperatures using the adjoint method. We specifically study steady-state conditions representative of the active surge phase in 2000, and the subsequent quiescent phase, using patterns of surface velocity observed in 2000, 2005, 2008 and 2015. Under constant geometry, temperature and geothermal heat, it is shown that surging increases basal freezing rates by over 60% across an area that is twice as large as the area over which the bed freezes in the quiescent phase. The process responsible for this

  18. Identification of storm surge vulnerable areas in the Philippines through the simulation of Typhoon Haiyan-induced storm surge levels over historical storm tracks

    NASA Astrophysics Data System (ADS)

    Lapidez, J. P.; Tablazon, J.; Dasallas, L.; Gonzalo, L. A.; Cabacaba, K. M.; Ramos, M. M. A.; Suarez, J. K.; Santiago, J.; Lagmay, A. M. F.; Malano, V.

    2015-07-01

    Super Typhoon Haiyan entered the Philippine Area of Responsibility (PAR) on 7 November 2013, causing tremendous damage to infrastructure and loss of lives mainly due to the storm surge and strong winds. Storm surges up to a height of 7 m were reported in the hardest hit areas. The threat imposed by this kind of natural calamity compelled researchers of the Nationwide Operational Assessment of Hazards (Project NOAH) which is the flagship disaster mitigation program of the Department of Science and Technology (DOST) of the Philippine government to undertake a study to determine the vulnerability of all Philippine coastal communities to storm surges of the same magnitude as those generated by Haiyan. This study calculates the maximum probable storm surge height for every coastal locality by running simulations of Haiyan-type conditions but with tracks of tropical cyclones that entered PAR from 1948-2013. One product of this study is a list of the 30 most vulnerable coastal areas that can be used as a basis for choosing priority sites for further studies to implement appropriate site-specific solutions for flood risk management. Another product is the storm tide inundation maps that the local government units can use to develop a risk-sensitive land use plan for identifying appropriate areas to build residential buildings, evacuation sites, and other critical facilities and lifelines. The maps can also be used to develop a disaster response plan and evacuation scheme.

  19. Identification of storm surge vulnerable areas in the Philippines through the simulation of Typhoon Haiyan-induced storm surge levels over historical storm tracks

    NASA Astrophysics Data System (ADS)

    Lapidez, J. P.; Tablazon, J.; Dasallas, L.; Gonzalo, L. A.; Cabacaba, K. M.; Ramos, M. M. A.; Suarez, J. K.; Santiago, J.; Lagmay, A. M. F.; Malano, V.

    2015-02-01

    Super Typhoon Haiyan entered the Philippine Area of Responsibility (PAR) 7 November 2013, causing tremendous damage to infrastructure and loss of lives mainly due to the storm surge and strong winds. Storm surges up to a height of 7 m were reported in the hardest hit areas. The threat imposed by this kind of natural calamity compelled researchers of the Nationwide Operational Assessment of Hazards (Project NOAH), the flagship disaster mitigation program of the Department of Science and Technology (DOST), Government of the Philippines, to undertake a study to determine the vulnerability of all Philippine coastal communities to storm surges of the same magnitude as those generated by Haiyan. This study calculates the maximum probable storm surge height for every coastal locality by running simulations of Haiyan-type conditions but with tracks of tropical cyclones that entered PAR from 1948-2013. One product of this study is a list of the 30 most vulnerable coastal areas that can be used as basis for choosing priority sites for further studies to implement appropriate site-specific solutions for flood risk management. Another product is the storm tide inundation maps that the local government units can use to develop a risk-sensitive land use plan for identifying appropriate areas to build residential buildings, evacuation sites, and other critical facilities and lifelines. The maps can also be used to develop a disaster response plan and evacuation scheme.

  20. Simulated storm surge effects on freshwater coastal wetland soil porewater salinity and extractable ammonium levels: Implications for marsh recovery after storm surge

    NASA Astrophysics Data System (ADS)

    McKee, M.; White, J. R.; Putnam-Duhon, L. A.

    2016-11-01

    Coastal wetland systems experience both short-term changes in salinity, such as those caused by wind-driven tides and storm surge, and long-term shifts caused by sea level rise. Salinity increases associated with storm surge are known to have significant effects on soil porewater chemistry, but there is little research on the effect of flooding length on salt penetration depth into coastal marsh soils. A simulated storm surge was imposed on intact soil columns collected from a non-vegetated mudflat and a vegetated marsh site in the Wax Lake Delta, LA. Triplicate intact cores were continuously exposed to a 35 salinity water column (practical salinity scale) for 1, 2, and 4 weeks and destructively sampled in order to measure porewater salinity and extractable NH4sbnd N at two cm depth intervals. Salinity was significantly higher in the top 8 cm for both the marsh and mudflat cores after one week of flooding. After four weeks of flooding, salinity was significantly higher in marsh and mudflat cores compared to the control (no salinity) cores throughout the profile for both sites. Extractable ammonium levels increased significantly in the marsh cores throughout the experiment, but there was only a marginally (p < 0.1) significant increase seen in the mudflat cores. Results indicate that porewater salinity levels can become significantly elevated within a coastal marsh soil in just one week. This vertical intrusion of salt can potentially negatively impact macrophytes and associated microbial communities for significantly longer term post-storm surge.

  1. The In Vivo Pericapsular Tissue Response to Modern Polyurethane Breast Implants.

    PubMed

    Frame, James; Kamel, Dia; Olivan, Marcelo; Cintra, Henrique

    2015-10-01

    Polyurethane breast implants were first introduced by Ashley (Plast Reconstr Surg 45:421-424, 1970), with the intention of trying to reduce the high incidence of capsular contracture associated with smooth shelled, high gel bleed, silicone breast implants. The sterilization of the polyurethane foam in the early days was questionable. More recently, ethylene oxide (ETO)-sterilized polyurethane has been used in the manufacturing process and this has been shown to reduce the incidence of biofilm. The improved method of attachment of polyurethane onto the underlying high cohesive gel, barrier shell layered, silicone breast implants also encourages bio-integration. Polyurethane covered, cohesive gel, silicone implants have also been shown to reduce the incidence of other problems commonly associated with smooth or textured silicone implants, especially with reference to displacement, capsular contracture, seroma, reoperation, biofilm and implant rupture. Since the introduction of the conical polyurethane implant (Silimed, Brazil) into the United Kingdom in 2009 (Eurosurgical, UK), we have had the opportunity to review histology taken from the capsules of polyurethane implants in three women ranging from a few months to over 3 years after implantation. All implants had been inserted into virgin subfascial, extra-pectoral planes. The results add to the important previously described histological findings of Bassetto et al. (Aesthet Plast Surg 34:481-485, 2010). Five distinct layers are identified and reasons for the development of each layer are discussed. Breast capsule around polyurethane implants, in situ for fifteen and 20 years, has recently been obtained and analysed in Brazil, and the histology has been incorporated into this study. After 20 years, the polyurethane is almost undetectable and capsular contracture may appear. These findings contribute to our understanding of polyurethane implant safety, and give reasoning for a significant reduction in clinical

  2. Heightened hurricane surge risk in northwest Florida revealed from climatological-hydrodynamic modeling and paleorecord reconstruction

    NASA Astrophysics Data System (ADS)

    Lin, Ning; Lane, Philip; Emanuel, Kerry A.; Sullivan, Richard M.; Donnelly, Jeffrey P.

    2014-07-01

    Historical tropical cyclone (TC) and storm surge records are often too limited to quantify the risk to local populations. Paleohurricane sediment records uncover long-term TC activity, but interpreting these records can be difficult and can introduce significant uncertainties. Here we compare and combine climatological-hydrodynamic modeling (including a method to account for storm size uncertainty), historical observations, and paleohurricane records to investigate local surge risk, using Apalachee Bay in northwest Florida as an example. The modeling reveals relatively high risk, with 100 year, 500 year, and "worst case" surges estimated to be about 6.3 m, 8.3 m, and 11.3 m, respectively, at Bald Point (a paleorecord site) and about 7.4 m, 9.7 m, and 13.3 m, respectively, at St. Marks (the head of the Bay), supporting the inference from paleorecords that Apalachee Bay has frequently suffered severe inundation for thousands of years. Both the synthetic database and paleorecords contain a much higher frequency of extreme events than the historical record; the mean return period of surges greater than 5 m is about 40 years based on synthetic modeling and paleoreconstruction, whereas it is about 400 years based on historical storm analysis. Apalachee Bay surge risk is determined by storms of broad characteristics, varies spatially over the area, and is affected by coastally trapped Kelvin waves, all of which are important features to consider when accessing the risk and interpreting paleohurricane records. In particular, neglecting size uncertainty may induce great underestimation in surge risk, as the size distribution is positively skewed. While the most extreme surges were generated by the uppermost storm intensities, medium intensity storms (categories 1-3) can produce large to extreme surges, due to their larger inner core sizes. For Apalachee Bay, the storms that induced localized barrier breaching and limited sediment transport (overwash regime; surge between 3

  3. Investigating Typhoon Induced River-Surge Interactions in the Tamsui Estuary, Taiwan.

    NASA Astrophysics Data System (ADS)

    Maskell; J. H.; Grieser, J.; Rodney, J.; Howe, N. J.

    2016-02-01

    It is increasingly important to understand the combined influence of the main drivers of coastal risk due to sea level rise and the potential increase in extreme weather events. An Asian Basin stochastic typhoon set was used to force a storm surge model of Taiwan to investigate the interaction between storm surge and high river discharges (50, 100 and 200 year return period discharges) in the Tamsui River. Taiwan is a mountainous country leading to the combined risk of surge and high river discharge occurring simultaneously in estuary regions. The typhoon tracks were selected using a Hurricane Surge Index (Kantha, 2006) and cross the northern tip of Taiwan with maximum sustained winds (Vmax) between 51 m/s and 75 m/s (Cat 3-5). Peak surge elevations in the Tamsui River range from 5.7 m to 10.3 m. The surge interacts with the river flow to induce changes in the water elevation between -8 m and 4 m depending on the surge elevation and river discharge and increases the inundated area in the range 37 km to 204 km. Significant positive interactions occur in the Tamsui Estuary (Fig. 1a) but do not have implications for increased inundation and occur at the start of the flood phase and the end of the ebb phase as previously shown in idealized test cases (Maskell et al., 2013). Current vectors in the estuary show that at the time leading up to high water the river outflow starts to become dominant in the mid-channel reducing maximum water levels by up to 10% in the combined surge and river solution. However, surge inhibits downstream propagation of the flood wave in the upper river channels increasing water levels by up to 2 m. The maximum inundated area (1330 km2) is caused by the combination of defence overflow due to the maximum surge (10.27 m) and increased river levels (RP100) in the upper channels leading to significant inundation either side of the Keelung River (Fig. 1b). The Erchung floodway is effective in diverting some of the flow (up to 10,443 m3/s) reducing

  4. Preliminary Study on Coupling Wave-Tide-Storm Surges Prediction System

    NASA Astrophysics Data System (ADS)

    You, S.; Park, S.; Seo, J.; Kim, K.

    2008-12-01

    The Korean Peninsula is surrounded by the Yellow Sea, East China Sea, and East Sea. This complex oceanographic system includes large tides in the Yellow Sea and seasonally varying monsoon and typhoon events. For Korea's coastal regions, floods caused by wave and storm surges are among the most serious threats. To predict more accurate wave and storm surge, the development of coupling wave-tide-storm surges prediction system is essential. For the time being, wave and storm surges predictions are still made separately in KMA (Korea Meteorological Administration) and most operational institute. However, many researchers have emphasized the effects of tides and storm surges on wind waves and recommended further investigations into the effects of wave-tide-storm surges interactions and coupling module on wave heights. However, tidal height and current give a great effect on the wave prediction in the Yellow sea where is very high tide and related research is not enough. At present, KMA has operated the wave (RWAM : Regional Wave Model) and storm surges/tide prediction system (RTSM : Regional Tide/Storm Surges Model) for ocean forecasting. The RWAM is WAVEWATCH III which is a third generation wave model developed by Tolman (1989). The RTSM is based on POM (Princeton Ocean Model, Blumberg and Mellor, 1987). The RWAM and RTSM cover the northwestern Pacific Ocean from 115°E to 150°E and from 20°N to 52°N. The horizontal grid intervals are 1/12° in both latitudinal and longitudinal directions. The development, testing and application of a coupling module in which wave-tide-storm surges are incorporated within the frame of KMA Ocean prediction system, has been considered as a step forward in respect of ocean forecasting. In addition, advanced wave prediction model will be applicable to the effect of ocean in the weather forecasting system. The main purpose of this study is to show how the coupling module developed and to report on a series of experiments dealing with the

  5. OBSERVATIONS OF MULTIPLE SURGES ASSOCIATED WITH MAGNETIC ACTIVITIES IN AR 10484 ON 2003 OCTOBER 25

    SciTech Connect

    Uddin, Wahab; Srivastava, Abhishek K.; Schmieder, B.; Chandra, R.; Bisht, S.; Kumar, Pankaj

    2012-06-10

    We present a multi-wavelength study of recurrent surges observed in H{alpha}, UV (Solar and Heliospheric Observatory (SOHO)/EIT), and Radio (Learmonth, Australia) from the super-active region NOAA 10484 on 2003 October 25. Several bright structures visible in H{alpha} and UV corresponding to subflares are also observed at the base of each surge. Type III bursts are triggered and RHESSI X-ray sources are evident with surge activity. The major surge consists of bunches of ejective paths forming a fan-shaped region with an angular size of ( Almost-Equal-To 65 Degree-Sign ) during its maximum phase. The ejection speed reaches up to {approx}200 km s{sup -1}. The SOHO/Michelson Doppler Imager magnetograms reveal that a large dipole emerges from the east side of the active region on 2003 October 18-20, a few days before the surges. On 2003 October 25, the major sunspots were surrounded by 'moat regions' with moving magnetic features (MMFs). Parasitic fragmented positive polarities were pushed by the ambient dispersion motion of the MMFs and annihilated with negative polarities at the borders of the moat region of the following spot to produce flares and surges. A topology analysis of the global Sun using Potential Field Source Surface shows that the fan structures visible in the EIT 171 A images follow magnetic field lines connecting the present active region to a preceding active region in the southeast. Radio observations of Type III bursts indicate that they are coincident with the surges, suggesting that magnetic reconnection is the driver mechanism. The magnetic energy released by the reconnection is transformed into plasma heating and provides the kinetic energy for the ejections. A lack of a radio signature in the high corona suggests that the surges are confined to follow the closed field lines in the fans. We conclude that these cool surges may have some local heating effects in the closed loops, but probably play a minor role in global coronal heating and the

  6. The eSurge-Venice project: altimeter and scatterometer satellite data to improve the storm surge forecasting in the city of Venice

    NASA Astrophysics Data System (ADS)

    Zecchetto, Stefano; De Biasio, Francesco; Umgiesser, Georg; Bajo, Marco; Vignudelli, Stefano; Papa, Alvise; Donlon, Craig; Bellafiore, Debora

    2013-04-01

    On the framework of the Data User Element (DUE) program, the European Space Agency is funding a project to use altimeter Total Water Level Envelope (TWLE) and scatterometer wind data to improve the storm surge forecasting in the Adriatic Sea and in the city of Venice. The project will: a) Select a number of Storm Surge Events occurred in the Venice lagoon in the period 1999-present day b) Provide the available satellite Earth Observation (EO) data related to the Storm Surge Events, mainly satellite winds and altimeter data, as well as all the available in-situ data and model forecasts c) Provide a demonstration Near Real Time service of EO data products and services in support of operational and experimental forecasting and warning services d) Run a number of re-analysis cases, both for historical and contemporary storm surge events, to demonstrate the usefulness of EO data The re-analysis experiments, based on hindcasts performed by the finite element 2-D oceanographic model SHYFEM (https://sites.google.com/site/shyfem/), will 1. use different forcing wind fields (calibrated and not calibrated with satellite wind data) 2. use Storm Surge Model initial conditions determined from altimeter TWLE data. The experience gained working with scatterometer and Numerical Weather Prediction (NWP) winds in the Adriatic Sea tells us that the bias NWP-Scatt wind is negative and spatially and temporally not uniform. In particular, a well established point is that the bias is higher close to coasts then offshore. Therefore, NWP wind speed calibration will be carried out on each single grid point in the Adriatic Sea domain over the period of a Storm Surge Event, taking into account of existing published methods. Point #2 considers two different methodologies to be used in re-analysis tests. One is based on the use of the TWLE values from altimeter data in the Storm Surge Model (SSM), applying data assimilation methodologies and trying to optimize the initial conditions of the

  7. The surge of great earthquakes from 2004 to 2014

    NASA Astrophysics Data System (ADS)

    Lay, Thorne

    2015-01-01

    During the decade from mid-2004 to mid-2014 18 great (Mw ≥ 8.0) earthquakes occurred globally (∼1.8 per year), compared to 71 from 1900 to mid-2004 (∼0.68 per year), yielding a short-term rate increase of 265%. Six events had Mw ≥ 8.5, larger than any prior event since the 1965 Rat Islands earthquake. The December 26, 2004 Mw 9.2 Sumatra earthquake had the longest recorded rupture length of 1300+ km and a rupture duration exceeding 450 s. The largest recorded strike-slip earthquake (Mw 8.7) occurred in the Indo-Australian plate on April 11, 2012. The largest recorded deep focus earthquake (Mw 8.3) occurred under the Sea of Okhotsk on May 24, 2013. While this overall surge of activity has not been demonstrated to be causally linked, regional spatio-temporal clustering is clearly evident for great events along the Sumatra, Kuril and Tonga subduction zones, and longer-range interactions have been established for global seismicity and seismic tremor at lower magnitudes following some of the events. This recent decade of intense great earthquake activity coincided with vastly expanded global networks of seismometers, GPS stations, tsunami gauges, and new satellite imaging capabilities such as InSAR and LandSAT interferometry and gravity measurements by GRACE and GOCE, enabling unprecedented analyses of precursory, co-seismic and post-seismic processes around the subduction zone environments where most of the events occurred. Individual events such as the March 11, 2011, Tohoku, Japan Mw 9.0 earthquake produced more ground motion and tsunami recordings than available for all great earthquakes of the last century collectively. Joint inversion and modeling of the diverse data sets exploit complementary sensitivity of the signals to different aspects of the earthquake processes. Major advances have been achieved in quantifying frictional locking and strain accumulation prior to some great events and in relating it to co-seismic slip heterogeneity. Many surprising

  8. Morning blood pressure surge: the reliability of different definitions.

    PubMed

    Stergiou, George S; Mastorantonakis, Stylianos E; Roussias, Leonidas G

    2008-08-01

    Preliminary evidence suggests that the morning surge (MS) in blood pressure (BP) is an independent predictor of cerebrovascular disease. However, the optimal definition of MS is uncertain. To compare the reproducibility of several MS definitions used in the literature, 132 untreated hypertensives were assessed with ambulatory BP monitoring twice, 2 weeks apart. Five MS definitions were compared. MS-1: the average BP of the first hour after rising minus the average BP of the first hour before rising; MS-2: BP 2 h after rising minus that of 2 h before rising; MS-3: BP 3 h after rising minus that of 3 h before rising; MS-4: BP 2 h after rising minus the average BP during sleep; MS-5: BP 2 h after rising minus the average BP of 3 consecutive readings, centered on the lowest reading during sleep. The reproducibility of each MS definition was assessed using the concordance correlation coefficient (CCC), the standard deviation of differences (SDD) and the coefficient of variation (CV) between repeated MS assessments, and the agreement in detecting "surgers," defined as subjects at the top quartile (Q4) of the MS distribution. CCCs were 0.20/0.30, 0.43/0.45, 0.53/0.51, 0.51/0.47, and 0.46/0.48 (systolic/diastolic) for MS-1 to MS-5 respectively; SDDs were 14.3/11.4, 12.1/9.9, 11.2/9.5, 10.3/8.2, and 11.9/9.8, respectively; CVs were 0.49/0.57, 0.44/0.39, 0.37/0.35, 0.36/0.31, and 0.27/0.24, respectively; and the agreement in detecting "surgers" was 69%/70%, 71%/76%, 75%/75%, 81%/83%, and 74%/75%, with kappa of 0.18/0.20, 0.23/0.36, 0.33/0.33, 0.49/0.53 and 0.29/0.31, respectively. There are important differences in the reproducibility of MS calculated by different methods. MS4 appears to provide the most reproducible definition of MS.

  9. Tsivat Basin conduit system persists through two surges, Bering Piedmont Glacier, Alaska

    USGS Publications Warehouse

    Fleisher, P.J.; Cadwell, D.H.; Muller, E.H.

    1998-01-01

    The 1993-1995 surge of Bering Glacier, Alaska, occurred in two distinct phases. Phase 1 of the surge began on the eastern sector in July, 1993 and ended in July, 1994 after a powerful outburst of subglacial meltwater into Tsivat Lake basin on the north side of Weeping Peat Island. Within days, jokulhlaup discharge built a 1.5 km2 delta of ice blocks (25-30 m) buried in outwash. By late October 1994, discharge temporarily shifted to a vent on Weeping Peat Island, where a second smaller outburst dissected the island and built two new sandar. During phase 2, which began in spring 1995 and ended within five months, continuous discharge issued from several vents along the ice front on Weeping Peat Island before returining to the Tsivat Basin. Surge related changes include a five- to six-fold increase in meltwater turbidity; the redirection of supercooled water in two ice-contact lakes; and an increase in the rate of glaciolacustrine sedimentation. US Geological Survey aerial photos by Austin Post show large ice blocks in braided channels indicating excessive subglacial discharge in a similar position adjacent to Weeping Peat Island during the 1966-1967 surge. During the subsequent three decades of retreat, the location of ice-marginal, subglacial discharge vents remained aligned on a linear trend that describes the position of a persistent subglacial conduit system. The presence of a major conduit system, possibly stabilized by subglacial bedrock topography, is suggested by: 1) high-level subglacial meltwater venting along the northern side of Weeping Peat Island during the 1966-1967 surge, 2) persistent low-level discharge between surges, and 3) the recurrence of localizing meltwater outbursts associated with both phases of the 1993-1005 surge.

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

    USGS Publications Warehouse

    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.

  11. Mitigation of hurricane storm surge impacts: Modeling scenarios over wide continental shelves

    NASA Astrophysics Data System (ADS)

    Lima Rego, Joao; Li, Chunyan

    2010-05-01

    The improvement of present understanding of surge dynamics over wide and shallow shelves is vital for the improvement of our ability to forecast storm surge impacts to coastal regions, particularly the low-lying land areas that are most vulnerable to hurricane flooding (e.g. the Northern Gulf of Mexico, coastal Bangladesh, the Southeast China sea). Given the increase of global sea-surface temperature, both the total number and proportion of intense tropical cyclones have increased notably since 1970 (Emanuel, 2005; Nature). Therefore, more intense hurricanes may hit densely populated coastal regions, and this problem may be aggravated by the prospect of accelerated sea-level rise in the 21st century. This presentation offers a review of recent work on hurricane-induced storm surge. The finite-volume coastal ocean model ("FVCOM", by Chen et al., 2003; J. Atmos. Ocean Tech.) was applied to the storm surge induced by Hurricanes Rita and Ike along the coasts of Louisiana and Texas in 2005 and 2008, respectively, to study coastal storm surge dynamics. The sensitivity analysis of Rego and Li (2009; Geophys. Res. Lett.) demonstrated how stronger, wider or faster tropical cyclones would affect coastal flooding. Li, Weeks and Rego (2009; Geophys. Res. Lett) looked into how hurricane flooding and receding dynamics differ, concluding that the overland flow in the latter stage is of considerable importance. Rego and Li (2010; J. Geophys. Res.) showed how extreme events may result of a combination of non-extreme factors, by studying the nonlinear interaction of tide and hurricane surge. The ability of models to reproduce these extreme events and to proactive plan for damage reduction is covered in Rego and Li's (2010; J. Marine Syst.) study of how barrier island systems protect coastal bays from offshore surge propagation. Here we combine these results for a wider perspective on how hurricane flooding could be mitigated under changing conditions.

  12. Corticosterone Blocks Ovarian Cyclicity and the LH Surge via Decreased Kisspeptin Neuron Activation in Female Mice

    PubMed Central

    Luo, Elena; Stephens, Shannon B. Z.; Chaing, Sharon; Munaganuru, Nagambika; Kauffman, Alexander S.

    2016-01-01

    Stress elicits activation of the hypothalamic-pituitary-adrenal axis, which leads to enhanced circulating glucocorticoids, as well as impaired gonadotropin secretion and ovarian cyclicity. Here, we tested the hypothesis that elevated, stress-levels of glucocorticoids disrupt ovarian cyclicity by interfering with the preovulatory sequence of endocrine events necessary for the LH surge. Ovarian cyclicity was monitored in female mice implanted with a cholesterol or corticosterone (Cort) pellet. Cort, but not cholesterol, arrested cyclicity in diestrus. Subsequent studies focused on the mechanism whereby Cort stalled the preovulatory sequence by assessing responsiveness to the positive feedback estradiol signal. Ovariectomized mice were treated with an LH surge-inducing estradiol implant, as well as Cort or cholesterol, and assessed several days later for LH levels on the evening of the anticipated surge. All cholesterol females showed a clear LH surge. At the time of the anticipated surge, LH levels were undetectable in Cort-treated females. In situ hybridization analyses the anteroventral periventricular nucleus revealed that Cort robustly suppressed the percentage of Kiss1 cells coexpressing cfos, as well as reduced the number of Kiss1 cells and amount of Kiss1 mRNA per cell, compared with expression in control brains. In addition, Cort blunted pituitary expression of the genes encoding the GnRH receptor and LHβ, indicating inhibition of gonadotropes during the blockage of the LH surge. Collectively, our findings support the hypothesis that physiological stress-levels of Cort disrupts ovarian cyclicity, in part, through disruption of positive feedback mechanisms at both the hypothalamic and pituitary levels which are necessary for generation of the preovulatory LH surge. PMID:26697722

  13. Health systems' "surge capacity": state of the art and priorities for future research.

    PubMed

    Watson, Samantha K; Rudge, James W; Coker, Richard

    2013-03-01

    Over the past decade, a number of high-impact natural hazard events, together with the increased recognition of pandemic risks, have intensified interest in health systems' ability to prepare for, and cope with, "surges" (sudden large-scale escalations) in treatment needs. In this article, we identify key concepts and components associated with this emerging research theme. We consider the requirements for a standardized conceptual framework for future research capable of informing policy to reduce the morbidity and mortality impacts of such incidents. Here our objective is to appraise the consistency and utility of existing conceptualizations of health systems' surge capacity and their components, with a view to standardizing concepts and measurements to enable future research to generate a cumulative knowledge base for policy and practice. A systematic review of the literature on concepts of health systems' surge capacity, with a narrative summary of key concepts relevant to public health. The academic literature on surge capacity demonstrates considerable variation in its conceptualization, terms, definitions, and applications. This, together with an absence of detailed and comparable data, has hampered efforts to develop standardized conceptual models, measurements, and metrics. Some degree of consensus is evident for the components of surge capacity, but more work is needed to integrate them. The overwhelming concentration in the United States complicates the generalizability of existing approaches and findings. The concept of surge capacity is a useful addition to the study of health systems' disaster and/or pandemic planning, mitigation, and response, and it has far-reaching policy implications. Even though research in this area has grown quickly, it has yet to fulfill its potential to generate knowledge to inform policy. Work is needed to generate robust conceptual and analytical frameworks, along with innovations in data collection and methodological

  14. Storm Surge Modelling of Super Typhoon Haiyan Event in Tacloban City, Leyte using MIKE 21 Model

    NASA Astrophysics Data System (ADS)

    Prelligera, Flor Angel; Caro, Carl Vincent; Ladiero, Christine; Mahar Francisco Lagmay, Alfredo; Lapidez, John Phillip; Malano, Vicente; Agaton, Rojelee; Santiago, Joy; Suarez, John Kenneth

    2014-05-01

    Super Typhoon Haiyan hit the Philippines on 08 November 2013 causing massive destruction to the central part of the country. Arguably the strongest tropical cyclone to make landfall in recorded history, Haiyan caused 6,201 deaths and damages amounting to PhP 36,690,882,497.27 (USD 824,390,091.77). The typhoon also brought about destructive storm surges reaching up to 7 meters in height. A better understanding of storm surge is essential to the development of mechanisms to mitigate the effects of similar events. Thus, a computer simulation of Haiyan with the resulting wave heights and storm surge levels was made using MIKE 21 model -- a software used for many different coastal and marine engineering projects worldwide. Simulations were made using the Hydrodynamic Flexible Mesh (HD FM) model coupled with the Spectral Wave (SW) model of the software. This coupled approach allows accurate calculations of both surge water levels and wave crest heights for overtopping of coastal structures. The maximum mesh flexibility of MIKE 21 allows mesh refinement for the coastal areas of Tacloban City within coarser mesh elements resulting to higher grid accuracy. Input parameters for the simulations of the coastline of Tacloban City, a densely populated coastal community heaviest hit by the storm surges of Haiyan, were obtained from the Philippine Atmospheric, Geophysical, and Astronomical Services Administration (PAGASA) and Japan Meteorological Agency (JMA). Atmospheric conditions such as wind and pressure values were input to a set of regional and local hydrodynamic and spectral wave models. Simulation results were compared with available tidal gauge records and the comparison showed good correlation. Coastal regional inundation maps were then created from the results of the storm surge simulations. These maps or its equivalent should be used to develop and further improve disaster risk management plans for future surge events. These plans include, but are not limited to

  15. Simulating complex storm surge dynamics: Three-dimensionality, vegetation effect, and onshore sediment transport

    NASA Astrophysics Data System (ADS)

    Lapetina, Andrew; Sheng, Y. Peter

    2015-11-01

    The 3-D hydrodynamics of storm surge events, including the effects of vegetation and impact on onshore transport of marine sediment, have important consequences for coastal communities. Here, complex storm surge dynamics during Hurricane Ike are investigated using a three-dimensional (3-D), vegetation-resolving storm surge-wave model (CH3D-SWAN) which includes such effects of vegetation as profile drag, skin friction, and production, dissipation, and transport of turbulence. This vegetation-resolving 3-D model features a turbulent kinetic energy (TKE) closure model, which uses momentum equations with vegetation-induced profile and skin friction drags, a dynamic q2 equation including turbulence production and dissipation by vegetation, as well as vegetation-dependent algebraic length-scale equations, and a Smagorinsky-type horizontal turbulence model. This vegetation model has been verified using extensive laboratory tests, but this study is a comparison of 2-D and 3-D simulations of complex storm surge dynamics during Hurricane Ike. We examine the value of 3-D storm surge models relative to 2-D models for simulating coastal currents, effects of vegetation on surge, and sediment transport during storm events. Comparisons are made between results obtained using simple 2-D formulations for bottom friction, the Manning coefficient (MC) approach, and physics-based 3-D vegetation-modeling (VM) approach. Last, the role that the 3-D hydrodynamics on onshore transport and deposition of marine sediments during the storm is investigated. While both the 3-D and 2-D results simulated the water level dynamics, results of the physics-based 3-D VM approach, as compared to the 2-D MC approach, more accurately captures the complex storm surge dynamics.

  16. Runoff-generated debris flows: Observations and modeling of surge initiation, magnitude, and frequency

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    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.

  17. Influence of resonance on tide and storm surge in the Gulf of Thailand

    NASA Astrophysics Data System (ADS)

    Tomkratoke, Saifhon; Sirisup, Sirod; Udomchoke, Veerasak; Kanasut, Jirawat

    2015-10-01

    A numerical simulation is used to determine the effective resonance period, quality factor Q and linear friction coefficient and mechanism of tide and storm surge in the Gulf of Thailand. The results indicated that the resonance response is triggered by the forced wave with the period of 20.25 hours. The Q factor and linear friction coefficient are approximately 3.15 and 2.76×10-5 ms-1, respectively. The gulf is regarded as a moderately dissipative system, which may yield small amplification for the oscillating forced wave. The resonance structure of the basin can play an important role in spatial distribution and amplification of tidal waves in the Gulf of Thailand and nearby area. Distance from the effective resonance period and the corresponding Q factor can be employed in characterizing of tidal amplification in the gulf. The study found that phase difference in the incoming tidal waves can induce the distortion of a nodal band to the normal mode analysis results. The resonance in the north-south direction is the principal mechanism to control tidal waves, specifically for the upper part of the gulf (the Gulf of Thailand). However, significant effect of resonance in the west-east direction on the amplification of tidal waves near the southern part of the gulf (Vietnam, Malaysia and Singapore coast) may be pronounced. From the reproduced historic storm surge and hypothetical results, the spatial distribution of storm surge elevation and the response ratio are in good agreement with the resonance mode and Q factor of the basin. Individually, the contribution of resonance factor to induce severe storm surge (positive surge) tends to be insignificant. Conversely, the interaction process between the disturbance system and the propagating surge wave in the gulf can induce large positive surge near the landfall location significantly.

  18. A probabilistic storm surge risk model for the German North Sea and Baltic Sea coast

    NASA Astrophysics Data System (ADS)

    Grabbert, Jan-Henrik; Reiner, Andreas; Deepen, Jan; Rodda, Harvey; Mai, Stephan; Pfeifer, Dietmar

    2010-05-01

    The German North Sea coast is highly exposed to storm surges. Due to its concave bay-like shape mainly orientated to the North-West, cyclones from Western, North-Western and Northern directions together with astronomical tide cause storm surges accumulating the water in the German bight. Due to the existence of widespread low-lying areas (below 5m above mean sea level) behind the defenses, large areas including large economic values are exposed to coastal flooding including cities like Hamburg or Bremen. The occurrence of extreme storm surges in the past like e.g. in 1962 taking about 300 lives and causing widespread flooding and 1976 raised the awareness and led to a redesign of the coastal defenses which provide a good level of protection for today's conditions. Never the less the risk of flooding exists. Moreover an amplification of storm surge risk can be expected under the influence of climate change. The Baltic Sea coast is also exposed to storm surges, which are caused by other meteorological patterns. The influence of the astronomical tide is quite low instead high water levels are induced by strong winds only. Since the exceptional extreme event in 1872 storm surge hazard has been more or less forgotten. Although such an event is very unlikely to happen, it is not impossible. Storm surge risk is currently (almost) non-insurable in Germany. The potential risk is difficult to quantify as there are almost no historical losses available. Also premiums are difficult to assess. Therefore a new storm surge risk model is being developed to provide a basis for a probabilistic quantification of potential losses from coastal inundation. The model is funded by the GDV (German Insurance Association) and is planned to be used within the German insurance sector. Results might be used for a discussion of insurance cover for storm surge. The model consists of a probabilistic event driven hazard and a vulnerability module, furthermore an exposure interface and a financial

  19. InSAR Observations and Finite Element Modeling of Crustal Deformation Around a Surging Glacier, Iceland

    NASA Astrophysics Data System (ADS)

    Spaans, K.; Auriac, A.; Sigmundsson, F.; Hooper, A. J.; Bjornsson, H.; Pálsson, F.; Pinel, V.; Feigl, K. L.

    2014-12-01

    Icelandic ice caps, covering ~11% of the country, are known to be surging glaciers. Such process implies an important local crustal subsidence due to the large ice mass being transported to the ice edge during the surge in a few months only. In 1993-1995, a glacial surge occurred at four neighboring outlet glaciers in the southwestern part of Vatnajökull ice cap, the largest ice cap in Iceland. We estimated that ~16±1 km3 of ice have been moved during this event while the fronts of some of the outlet glaciers advanced by ~1 km.Surface deformation associated with this surge has been surveyed using Interferometric Synthetic Aperture Radar (InSAR) acquisitions from 1992-2002, providing high resolution ground observations of the study area. The data show about 75 mm subsidence at the ice edge of the outlet glaciers following the transport of the large volume of ice during the surge (Fig. 1). The long time span covered by the InSAR images enabled us to remove ~12 mm/yr of uplift occurring in this area due to glacial isostatic adjustment from the retreat of Vatnajökull ice cap since the end of the Little Ice Age in Iceland. We then used finite element modeling to investigate the elastic Earth response to the surge, as well as confirm that no significant viscoelastic deformation occurred as a consequence of the surge. A statistical approach based on Bayes' rule was used to compare the models to the observations and obtain an estimate of the Young's modulus (E) and Poisson's ratio (v) in Iceland. The best-fitting models are those using a one-kilometer thick top layer with v=0.17 and E between 12.9-15.3 GPa underlain by a layer with v=0.25 and E from 67.3 to 81.9 GPa. Results demonstrate that InSAR data and finite element models can be used successfully to reproduce crustal deformation induced by ice mass variations at Icelandic ice caps.Fig. 1: Interferograms spanning 1993 July 31 to 1995 June 19, showing the surge at Tungnaárjökull (Tu.), Skaftárjökull (Sk.) and S

  20. Probabilistic storm surge inundation maps for Metro Manila based on Philippine public storm warning signals

    NASA Astrophysics Data System (ADS)

    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.

    2015-03-01

    A storm surge is the sudden rise of sea water over the astronomical tides, generated by an approaching storm. This event poses a major threat to the Philippine coastal areas, as manifested by Typhoon Haiyan on 8 November 2013. This hydro-meteorological hazard is one of the main reasons for the high number of casualties due to the typhoon, with 6300 deaths. It became evident that the need to develop a storm surge inundation map is of utmost importance. To develop these maps, 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. The Japan Meteorological Agency storm surge model was used to simulate storm surge heights. The frequency distribution of the maximum storm surge heights was calculated using simulation results of tropical cyclones 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 inundation for a specific PSWS using the probability of exceedance derived from the frequency distribution. Buildings and other structures were assigned a probability of exceedance depending on their occupancy category, i.e., 1% probability of exceedance for critical facilities, 10% probability of exceedance for special occupancy structures, and 25% for standard occupancy and miscellaneous structures. The maps produced show the storm-surge-vulnerable areas in Metro Manila, illustrated by the flood depth of up to 4 m and extent of up to 6.5 km from the coastline. This information can help local government units in developing early warning systems, disaster preparedness and mitigation plans, vulnerability assessments, risk-sensitive land use plans, shoreline

  1. Centrifugal Compressor Surge Margin Improved With Diffuser Hub Surface Air Injection

    NASA Technical Reports Server (NTRS)

    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

  2. Impacts of land cover changes on hurricane storm surge in the lower Chesapeake Bay

    NASA Astrophysics Data System (ADS)

    Denton, M.; Lawler, S.; Ferreira, C.

    2013-12-01

    The Chesapeake Bay is the largest estuary in the United States with more than 150 rivers draining into the bay's tidal wetlands. Coastal wetlands and vegetation play an important role in shaping the hydrodynamics of storm surge events by retaining water and slowing the propagation of storm surge. In this way coastal wetlands act as a natural barrier to inland flooding, particularly against less intense storms. Threats to wetlands come from both land development (residential or commercial/industrial) and sea level rise. The lower region of the Chesapeake Bay near its outlet is especially vulnerable to flooding from Atlantic storm surge brought in by hurricanes, tropical storms and nor'easters (e.g., hurricanes Isabel [2003] and Sandy [2012]). This region is also intensely developed with nearly 1.7 million residents within the greater Hampton Roads metropolitan area. Anthropogenic changes to land cover in the lower bay can directly impact basin drainage and storm surge propagation with impacts reaching beyond the immediate coastal zone to affect flooding in inland areas. While construction of seawall barriers around population centers may provide storm surge protection to a specifically defined area, these barriers deflect storm surge rather than attenuate it, underscoring the importance of wetlands. To analyze these impacts a framework was developed combining numerical simulations with a detailed hydrodynamic characterization of flow through coastal wetland areas. Storm surges were calculated using a hydrodynamic model (ADCIRC) coupled to a wave model (SWAN) forced by an asymmetric hurricane vortex model using the FEMA region 3 unstructured mesh (2.3 million nodes) under a High Performance Computing (HPC) environment. Multiple model simulations were performed using historical hurricanes data and hypothetical storms to compare the predicted storm surge inundation with various levels of wetland reduction and/or beach hardening. These data were combined and overlaid

  3. Optical dating of late Holocene storm surges from Schokland (Noordoostpolder, the Netherlands)

    NASA Astrophysics Data System (ADS)

    van den Biggelaar, Don; Kluiving, Sjoerd; van Balen, Roland; Kasse, Cronelils; Troelstra, Simon; Prins, Maarten; Wallinga, Jakob; Versendaal, Alice

    2015-04-01

    Storm surges have a major impact on land use and human habitation in coastal regions. Our understanding of this impact can be improved by correlating long-term historical storm records with sedimentary evidence of storm surges, but so far few studies use such an approach. Here we present detailed geological and historical data on late Holocene storm surges from the former island Schokland, located in the northern part of Flevoland (central Netherlands). During the late Holocene, Schokland transformed from a peat area that gradually inundated (~1200 yr ago) via an island in a marine environment (~400 yr ago) to a land-locked island in the reclaimed Province of Flevoland (~70 yr ago). Deposits formed between 1200 and 70 year ago on lower parts of the island, consist of a stacked sequence of clay and sand layers, with the latter being deposited during storm surges. We dated the sandy laminae of late Holocene storm surges in the clay deposit on Schokland to improve the age model of the island's flooding history during the last 1200 years. Samples for dating were obtained from a mechanical core at Schokland. The top of the peat underlying the clay and sand deposits was dated using 14C accelerator mass spectrometry (AMS) of terrestrial plant and seed material. Sandy intervals of the flood deposits were dated using a series of ten quartz OSL ages, which were obtained using state-of-the-art methods to deal with incomplete resetting of the OSL signal. These new dates, together with laboratory analyses on the clay deposit (thermogravimetric analysis, grain-size analyses, foraminifera, bivalves and ostracods) and a literature study show that storm surges had a major impact on both the sedimentary and the anthropogenic history of Schokland. The results show that the stacked clay sequence is younger than expected, indicating either an increasing sedimentation rate or reworking of the clay by storm surges. Furthermore, the results indicate that a correlation can be made between

  4. Shoreline Tracing Using Medium to High-Resolution Satellite Images for Storm Surge Modelling

    NASA Astrophysics Data System (ADS)

    Ladiero, C.; Lagmay, A. M. A.; Santiago, J. T.; Suarez, J. K. B.; Puno, J. V.; Bahala, M. A.

    2014-12-01

    In a developing country like Philippines, which ranks fourth in the longest coastline in the world at 36 289 kilometers, acquiring an updated and finer shoreline at the municipal level is mostly scarce. Previous studies have emphasized the importance of accurately delineating shoreline in coastal management, engineering design, sea-level rise research, coastal hazard map development, boundary definition, coastal change research and monitoring and numerical models. In the context of storm surge modelling, shoreline boundary serves as basis for tidal conditions and requires to be well-defined to generate an accurate simulation result. This paper presents the cost-effective way of shoreline tracing employed by the Storm Surge component under the Department of Science and Technology-Nationwide Operational Assessment of Hazards (DOST-Project NOAH) for use in modelling storm surge hazards in the country, particularly in San Pedro Bay during the Typhoon Haiyan. Project NOAH was tasked to conduct disaster science research and development and recommend innovative information services in government's disaster prevention and mitigation efforts through cutting edge technologies. The Storm Surge component commenced in September 2013 and was mandated by the Philippine government to identify storm surge vulnerable areas and provide high-resolution maps of storm surge inundation in the localities. In the absence of LIDAR data at the time, the Project utilized the freely available medium to high resolution satellite images of Google Earth and digitized the shoreline. To minimize subjectivity, set of digitizing standards were developed for classifying common shoreline features in the country, differentiating image textures and colors and tabulating identified shoreline features. After which, the digitized shoreline were quality checked and corrected for topology using ArcGIS Desktop 10 software. The final output is a vector data that served as boundary for topo-bathy extraction

  5. The distribution of storm surge scale along east coast of China and its response to climate change

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Li, G.

    2016-12-01

    Under global climate change, Storm surge resulted in more severe damages along the coastal areas of China. Consideration of how climate change impacts on storm surge is important to ensure readiness for disaster response. Relations among climate change, landfall features of tropical cyclone, and distribution pattern of storm surge in different phases have not yet been reliably quantified. In previous works to analyze the storm surge changing features under climate change commonly used simplified statistics to calculate the number, numerical modeling to simulate the range of influence of a specific tropical cyclone or calculate the return period which are not consider spatial temporal continuity in storm surge scale feature. This study proposed a distribution of storm surge scale combines the spatial distribution and tidal elevations which presents the inherent rules and long-term trends of storm surge. An improved spatial grid and statistical analysis have been used to describe the distribution of storm surge scale and to explain how climate change work on it. Climate change has most important effect on long-term evolution of tropical cyclone landfall along the east coast of China. Because of the regularities of tropical cyclone distribution in a period is the result of comprehensive work of all climate change factors. The distribution features of tropical cyclone in different phases are used to be the proxy data of climate status at the same time which called climate substitute model in this study. Tropical cyclone generated storm surge scale will follow the change of landfall tropical cyclone long-term distribution. Hereby build a corresponding tropical storm surge scale distribution pattern along the coastal area is a spatial-temporal consistency method connect evolution processes of storm surge scale and the climate substitute modal. These results is a reference for the future storm surge simulation and useful for emergency management.

  6. Swift snowmelt and floods (lahars) caused by great pyroclastic surge at Mount St Helens volcano, Washington, 18 May 1980

    USGS Publications Warehouse

    Waitt, R.B.

    1989-01-01

    The initial explosions at Mount St. Helens, Washington, on the moring of 18 May 1980 developed into a huge pyroclastic surge that generated catastrophic floods off the east and west flanks of the volcano. Near-source surge deposits on the east and west were lithic, sorted, lacking in accretionary lapilli and vesiculated ash, not plastered against upright obstacles, and hot enough to char wood - all attributes of dry pyroclastic surge. Material deposited at the surge base on steep slopes near the volcano transformed into high-concentration lithic pyroclastic flows whose deposits contain charred wood and other features indicating that these flows were hot and dry. Stratigraphy shows that even the tail of the surge had passed the east and west volcano flanks before the geomorphically distinct floods (lahars) arrived. This field evidence undermines hypotheses that the turbulent surge was itself wet and that its heavy components segregated out to transform directly into lahars. Nor is there evidence that meters-thick snow-slab avalanches intimately mixed with the surge to form the floods. The floods must have instead originated by swift snowmelt at the base of a hot and relatively dry turbulent surge. Impacting hot pyroclasts probably transferred downslope momentum to the snow surface and churned snow grains into the surge base. Melting snow and accumulating hot surge debris may have moved initially as thousands of small thin slushflows. As these flows removed the surface snow and pyroclasts, newly uncovered snow was partly melted by the turbulent surge base; this and accumulating hot surge debris in turn began flowing, a self-sustaining process feeding the initial flows. The flows thus grew swiftly over tens of seconds and united downslope into great slushy ejecta-laden sheetfloods. Gravity accelerated the floods to more than 100 km/h as they swept down and off the volcano flanks while the snow component melted to form great debris-rich floods (lahars) channeled into

  7. INCREASED FLEXIBILITY OF TURBO-COMPRESSORS IN NATURAL GAS TRANSMISSION THROUGH DIRECT SURGE CONTROL

    SciTech Connect

    Robert J. McKee; Shane P. Siebenaler; Danny M. Deffenbaugh

    2005-02-25

    The objective of this Direct Surge Control project was to develop a new internal method to avoid surge of pipeline compressors. This method will safely expand the range and flexibility of compressor operations, while minimizing wasteful recycle flow at the lower end of the operating envelope. The approach is to sense the onset of surge with a probe that directly measures re-circulation at the impeller inlet. The signals from the probe are used by a controller to allow operation at low flow conditions without resorting to a predictive method requiring excessive margin to activate a recycle valve. The sensor developed and demonstrated during this project was a simple, rugged, and sensitive drag probe. Experiments conducted in a laboratory compressor clearly showed the effectiveness of the technique. Subsequent field demonstrations indicated that the increase in range without the need to recycle flow was on the order of 19% to 25%. The cost benefit of applying the direct surge control technology appears to be as much as $120 per hour per compressor for operation without the current level of recycle flow. This could amount to approximately $85 million per year for the U.S. Natural Gas Transmission industry, if direct surge control systems are applied to most pipeline centrifugal compressors.

  8. Storm Surge and Non-Tidal Ocean Loading Effects on Geodetic GPS Observations

    NASA Astrophysics Data System (ADS)

    Williams, S. D.; Penna, N. T.; Teferle, F. N.; Geng, J.

    2009-12-01

    GPS observations used in geodetic and geophysical studies are not usually corrected for non-tidal ocean loading displacement, such as caused by storm surges. Using the POLSSM high resolution model that provides non-tidal hourly sea levels covering the North Sea region with approximately 12 km grid cells, we demonstrate that such non-tidal ocean loading height displacements can reach up to 30 mm at the time of a storm surge. By correcting for this displacement at the observation level, we show that GIPSY precise point positioning daily height estimates (using reprocessed JPL orbital products) for continuous GPS sites around the North Sea are sensitive to non-tidal ocean loading both during and outside of times of storm surges. We consider 5 years of CGPS data and demonstrate that GPS height estimates should be corrected for non-tidal ocean loading if the highest precisions are to be obtained in regions susceptible to storm surges such as the North Sea, the Bay of Bengal and the Gulf of Mexico. For example, for a 30 day window in November 2007 centred about a surge arising from storm Tilo, we obtain improvements in height precision of nearly 50% at some sites. We also assess whether global non-tidal models such as ECCO are sufficient, or whether the higher resolution models such as POLSSM are required, including their effect on the time series noise characteristics.

  9. The Eyjabakkajökull glacial landsystem, Iceland: Geomorphic impact of multiple surges

    NASA Astrophysics Data System (ADS)

    Schomacker, Anders; Benediktsson, Ívar Örn; Ingólfsson, Ólafur

    2014-08-01

    A new glacial geomorphological map of the Eyjabakkajökull forefield in Iceland is presented. The map covers c. 60 km2 and is based on high-resolution aerial photographs recorded in August 2008 as well as field checking. Landforms are manually registered in a geographical information system (ArcGIS) based on inspection of orthorectified imagery and digital elevation models of the area. We mapped subglacially streamlined landforms such as flutes and drumlins on the till plain, supraglacial landforms such as ice-cored moraine, pitted outwash, and concertina eskers, and ice-marginal landforms such as the large, multi-crested 1890 surge end moraine and smaller single-crested end moraines. The glaciofluvial landforms are represented by outwash plains, minor outwash fans, and sinuous eskers. Extramarginal sediments were also registered and consist mainly of old sediments in wetlands or locally weathered bedrock. Eyjabakkajökull has behaved as a surge-type glacier for 2200 years; hence, the mapped landforms originate from multiple surges. Landforms such as large glaciotectonic end moraines, hummocky moraine, long flutes, crevasse-fill ridges, and concertina eskers are characteristic for surge-type glaciers. The surging glacier landsystem of Eyjabakkajökull serves as a modern analog to the landsystems of terrestrial paleo-ice streams.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    Bastidas, L. A.; Knighton, J.; Kline, S. W.

    2015-10-01

    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 eleven 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 amount of interactions between parameters and a non-linear 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.

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

    NASA Astrophysics Data System (ADS)

    Bastidas, Luis A.; Knighton, James; Kline, Shaun W.

    2016-09-01

    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.

  13. Introduction on the operational storm surge forecasting system in Korea Operational Oceanographic System (KOOS)

    NASA Astrophysics Data System (ADS)

    Kwon, Jae-Il; Park, Kwang-Soon; Choi, Jung-Woon; Lee, Jong-Chan; Heo, Ki-Young; Kim, Sang-Ik

    2017-04-01

    During last more than 50 years, 258 typhoons passed and affected the Korean peninsula in terms of high winds, storm surges and extreme waves. In this study we explored the performance of the operational storm surge forecasting system in the Korea Operational Oceanographic System (KOOS) with 8 typhoons from 2010 to 2016. The operation storm surge forecasting system for the typhoon in KOOS is based on 2D depth averaged model with tides and CE (U.S. Army Corps of Engineers) wind model. Two key parameters of CE wind model, the locations of typhoon center and its central atmospheric pressure are based from Korea Meteorological administrative (KMA)'s typhoon information provided from 1 day to 3 hour intervals with the approach of typhoon through the KMA's web-site. For 8 typhoons cases, the overall errors, other performances and analysis such as peak time and surge duration are presented in each case. The most important factor in the storm surge errors in the operational forecasting system is the accuracy of typhoon passage prediction.

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

    PubMed

    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.

  15. Typhoon storm surges observed by Chinese HY-2a satellite radar altimetry

    NASA Astrophysics Data System (ADS)

    Yang, Jingsong; Li, Xiaohui; Han, Guoqi; Chen, Dake

    2017-04-01

    Storm surge induced by an tropical cyclone (or typhoon/hurricane) is often the greatest threat to life and property of coastal areas. HY-2A is the first Chinese ocean dynamic environment monitoring satellite, which was launched in August 2011. The satellite repeats its ground track every 14 days. It plays an important role in global monitoring of sea surface winds (especially extreme winds like typhoons and hurricanes), ocean waves, currents, eddies, and extreme events like storm surges by using its four major payloads, i.e. radar altimetry, microwave scatterometer, scanning microwave radiometer and calibration microwave radiometer. The HY-2A data are obtained from China's National Satellite Ocean Application Service (NSOAS). We use 1 s along-track data with a nominal spatial resolution of about 7 km. The altimetry data are corrected for wet tropospheric (based on the onboard calibration microwave radiometer) and ionospheric path delays, and for ocean, solid earth and pole tides. Several typhoon storm surges were observed by HY-2A satellite altimetry. The storm surge magnitude and the cross-shelf e-folding decay scale are given. The present study shows that the HY-2A satellite altimetry is a useful tool for monitoring typhoon storm surges.

  16. Comparison of storm surges in eastern and western Louisiana lake estuaries

    NASA Astrophysics Data System (ADS)

    Huang, W.; Li, C.; Milan, B.; Weeks, E.

    2016-02-01

    Coastal Louisiana experiences hurricane storm surges, mostly in summer, on an irregular inter-annual basis and winter storm surges on a quasi-regular seasonal basis every late fall to the following spring. Some of the important fish habitats in southern Louisiana are shallow lake estuaries with seasonally variable river discharges. They are surrounded by wetlands and with very limited connections with the coastal ocean through narrow channels ( 100 m wide). The storm surge related flushing of these systems are of importance to the sediment transport, wetland and ecosystem health, and the surrounding community. In the present work, we present a comparison between two such semi-enclosed lake-estuarine systems, one in the west and one in the east of the southern Louisiana coast - the Calcasieu Lake Estuary and Lake Pontchartrain Estuary. Data for several storm surges have been collected by our team. These data are analyzed for both systems, focusing on the basin scale oscillation and flushing of the systems in response to the atmospheric forcing. We have applied a Weather Research Forecast (WRF) model to provide insight to how the atmospheric forcing evolves. Using the WRF model output as forcing, we applied a hydrodynamic model for the response of these lake estuaries. With the extensive data and model experiments, we are able to compare the storm surges and flushing of the two lake estuarine systems in the western and eastern Louisiana.

  17. Impact of Hurricane Rita storm surge on sugarcane borer (Lepidoptera: Crambidae) management in Louisiana.

    PubMed

    Beuzelin, J M; Reagan, T E; Akbar, W; Cormier, H J; Flanagan, J W; Blouin, D C

    2009-06-01

    Twelve thousand to 16,000 ha of Louisiana sugarcane (Saccharum spp.) fields were flooded by saltwater from the Hurricane Rita storm surge in September 2005. A four treatment, 12-replication study comparing storm surge flooded and nonflooded plant and ratoon sugarcane fields was conducted during summer 2006 to assess sugarcane borer, Diatraea saccharalis (F.), pest severity, pest control actions, and soil-associated arthropod abundance and diversity. Even with a significant 2.4-fold increase in the average number of insecticide applications used for D. saccharalis management in flooded fields, growers still incurred higher injury. A significant 2.8-fold reduction in the predaceous red imported fire ant, Solenopsis invicta Buren, was associated with the storm surge, whereas no reduction in abundance of other soil-associated arthropods was recorded. Arthropod diversity measured by the Shannon diversity index significantly increased by a factor of 1.3 in sugarcane fields flooded by the storm surge. Increase in D. saccharalis pest severity associated with the storm surge caused an estimated loss in revenue between $1.9 and $2.6 million to the Louisiana sugarcane industry for the 2006 production season.

  18. A storm surge intensity classification based on extreme water level and concomitant wave height

    NASA Astrophysics Data System (ADS)

    Dong, Sheng; Gao, Junguo; Li, Xue; Wei, Yong; Wang, Liang

    2015-04-01

    Storm surge is one of the predominant natural threats to coastal communities. Qingdao is located on the southern coast of the Shandong Peninsula in China. The storm surge disaster in Qingdao depends on various influencing factors such as the intensity, duration, and route of the passing typhoon, and thus a comprehensive understanding of natural coastal hazards is essential. In order to make up the defects of merely using the warning water level, this paper presents two statistical distribution models (Poisson Bi-variable Gumbel Logistic Distribution and Poisson Bi-variable Log-normal Distribution) to classify the intensity of storm surge. We emphasize the joint return period of typhoon-induced water levels and wave heights measured in the coastal area of Qingdao since 1949. The present study establishes a new criterion to classify the intensity grade of catastrophic storms using the typhoon surge estimated by the two models. A case study demonstrates that the new criterion is well defined in terms of probability concept, is easy to implement, and fits well the calculation of storm surge intensity. The procedures with the proposed statistical models would be useful for the disaster mitigation in other coastal areas influenced by typhoons.

  19. The optimization of design parameters for surge relief valve for pipeline systems

    NASA Astrophysics Data System (ADS)

    Kim, Hyunjun; Hur, Jisung; Kim, Sanghyun

    2017-06-01

    Surge is an abnormal pressure which induced by rapid changes of flow rate in pipeline systems. In order to protect pipeline system from the surge pressure, various hydraulic devices have been developed. Surge-relief valve(SRV) is one of the widely applied devices to control surge due to its feasibility in application, efficiency and cost-effectiveness. SRV is designed to automatically open under abnormal pressure and discharge the flow and makes pressure of the system drop to the allowable level. The performance of the SRV is influenced by hydraulics. According to previous studies, there are several affecting factors which determine performance of the PRV such as design parameters (e.g. size of the valve), system parameters (e.g. number of the valves and location of the valve), and operation parameters (e.g. set point and operation time). Therefore, the systematic consideration for factors affecting performance of SRV is required for the proper installation of SRV in the system. In this study, methodology for finding optimum parameters of the SRV is explored through the integration of Genetic Algorithm(GA) into surge analysis.

  20. The dynamics of flow and sediment transport during Karakoram surge cycles

    NASA Astrophysics Data System (ADS)

    Quincey, D. J.; Bishop, M. P.; Sevestre, H.; Glasser, N. F.

    2010-12-01

    An increasing number of glaciers have been reported to be advancing and thickening in the Karakoram, which is anomalous in the wider context of Himalayan mountain glacier recession. There has been a coincident increase in the number and magnitude of glacier surges, events that greatly accelerate surface erosional and depositional processes, with an associated impact on tectonic uplift rates. Despite their importance for landscape evolution on a variety of timescales, there remains a paucity of quantitative data relating to glacier surge dynamics, or any rigorous assessment of their impact on landscape geomorphology. In this study, optical matching of Landsat satellite image pairs is used to derive glacier velocity data for three glaciers before, during and after recent surge events. These data show that glacier flow can increase by up to two orders of magnitude during surge events when compared with quiescent velocities, and allow for first order determination of the importance of basal sliding vs internal deformation in glacier motion in the region. Multi-temporal geomorphological mapping highlights the rapid modification of glacier surface features that reflect a progressive re-arrangement of glacier flow within individual flow units and demonstrate that surface debris can be transported several kilometers down-glacier within a single surge cycle. Combined, these data provide a critical first step in understanding the short-term erosional capability of glaciers, which has important implications for understanding landscape evolution within a complex, tectonically active environment.

  1. Tide-surge and wave interaction in the Gulf of Maine during an extratropical storm

    NASA Astrophysics Data System (ADS)

    Zou, Qingping; Xie, Dongmei

    2016-12-01

    The fully coupled spectral wave and circulation model SWAN + ADCIRC was applied to investigate tide-surge and wave interaction in the Gulf of Maine during the extratropical storm on Patriot's Day of 2007. Significant tide-surge and wave interaction was found over Georges Bank and in the coastal areas. Over Georges Bank, the wave-induced current reached 0.2 m/s at the storm peak, accounting for 17 % of the total depth-averaged current. In Saco Bay, the current was dominated by wave-induced current with a magnitude up to 1.0 m/s during the storm. Two clockwise circulation gyres were found to form and sustain over a period of 26 hours during the storm in the bay. They were driven by spatial variations of wave height, direction and the resulting wave radiation stress gradient. Wave setup reached 0.2 m at the storm peak along the coast of Saco Bay. In Saco Bay, wave energy dissipation was reduced and wave height increased due to the increased water depth at high tide and surge. Therefore, wave height was modulated by tide and surge accordingly along the coast. As a result, wave setup and wave-induced current in the bay were also modulated by tide and surge. During the tidal cycle at the storm peak, wave setup increased with tidal level and the maximum wave setup coincided with high tide.

  2. Changes of storm surges in the Bohai Sea derived from a numerical model simulation, 1961-2006

    NASA Astrophysics Data System (ADS)

    Feng, Jianlong; von Storch, Hans; Weisse, Ralf; Jiang, Wensheng

    2016-10-01

    Using the tide-surge circulation model ADCIRC, the storm surges in the Bohai Sea were hindcasted from 1961 to 2006 after a regional model-based reconstruction of wind conditions. Through comparison with four storm surge cases that happened in the Bohai Sea and long-time observations at four tide gauges in the Yellow Sea, it is concluded that the model is capable of reproducing the conditions of storm surges in the past few decades in this area. The spatial distribution, the seasonal variation, the interdecadal variability, and the long-time trend were analyzed using the model results. Results show that the storm surges in the three bays of the Bohai Sea are more serious than those in other areas. The storm surges exhibit obvious seasonal variations—they are more serious in spring and autumn. Obvious interdecadal variations and long-time decreasing trends take place in the Bohai Sea. Storm surge indices show statistically significant negative correlations to the Arctic Oscillation (AO) and a statistically significant positive correlation to the Siberian High (SH). Linear regression analysis was used to determine a robust link between the indices of the storm surges and the AO and SH. Using this link, conditions of the storm surges from 1900 to 2006 were estimated from the long-time AO and SH.

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

    PubMed Central

    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

  4. Sedimentological features of the surge emitted during the August, 2006 pyroclastic eruption at Tungurahua volcano (Ecuador)

    NASA Astrophysics Data System (ADS)

    Douillet, G.; Goldstein, F.; Lavallee, Y.; Hanson, J. B.; Kueppers, U.; Robin, C.; Ramon, P.

    2009-12-01

    Tungurahua volcano, Ecuador, is a stratovolcano, which began a new eruptive phase in 1999. Notable pyroclastic Density Currents (PDC) were generated in July (VEI 2) and August (VEI 3) 2006 and covered its N and W flanks. PDCs and associated lahars represent a major hazard for 20,000 inhabitants and an hydrological dam. The volcano has been monitored by the Instituto Geofisico of the Escuela Politécnica Nacional of Quito, since 1988. Field work carried out in 2009 provide information on the behavior of the fine-grained fraction of the PDC (i.e., surge) during transport and deposition. We mapped out the sedimentological characteristics of the deposits and distinguished three depositional environments: 1- The core of the deposit, up to several m in thickness, is confined to valleys and consists of poorly-sorted lapilli scoria and blocks (cm to m scale) and a small fraction of ash matrix. Ongoing analysis of the ash matrix will help to understand the link between the main PDC and the associated surge. 2- On ridges and outer margins of valleys, the deposits total a thickness of 10s to 100s cm and consist of fine- to coarse-grain ashes organized in cm-scale beds. Horizontal to cross bed laminations with 10-cm long wavelength prevail. They are typical of deposition under sustained high-energy current, which we associate with the flow of a surge. 3- In the distal part of surge deposits, we observe fine grained surge deposits with a thickness up to ca. 5 m. The characteristic structures are curved crested dunes, 10s of cm high and up to 10s of m long, with dip angles ranging from 15 to 35° and a strongly asymmetric shape. The steepest side tends to be the upslope face. Dunes show mainly a climbing structure, with beds cm in thickness, but some are more complicated, containing cut and fill structures, interpreted as late-stage pulses of energetic turbulence. No displacement dunes were observed in this area. Using the flow direction given by 100s of dunes, we provide

  5. Operational storm surge forecasting in the Netherlands: developments in the last decade.

    PubMed

    Verlaan, Martin; Zijderveld, Annette; de Vries, Hans; Kroos, Jan

    2005-06-15

    The accurate forecasting of storm surges is an important issue in the Netherlands. With the emergence of the first numerical hydrodynamic models for surge forecasting at the beginning of the 1980s, new demands and possibilities were raised. This article describes the main phases of the development and the present operational set-up of the Dutch continental shelf model, which is the main hydrodynamic model for storm surges in the Netherlands. It includes a brief discussion of applied data-assimilation techniques, such as Kalman filtering, the model calibration process and some thoughts on quality assurance in an operational environment. After further describing some select recent investigations, the paper concludes with some remarks on future developments in a European context.

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

    PubMed

    Peng, Shiqiu; Li, Yineng

    2015-10-26

    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.

  7. Testing of high voltage surge protection devices for use in liquid argon TPC detectors

    NASA Astrophysics Data System (ADS)

    Asaadi, J.; Conrad, J. M.; Gollapinni, S.; Jones, B. J. P.; Jostlein, H.; St. John, J. M.; Strauss, T.; Wolbers, S.; Zennamo, J.

    2014-09-01

    In this paper we demonstrate the capability of high voltage varistors and gas discharge tube arrestors for use as surge protection devices in liquid argon time projection chamber detectors. The insulating and clamping behavior of each type of device is characterized in air (room temperature), and liquid argon (90 K), and their robustness under high voltage and high energy surges in cryogenic conditions is verified. The protection of vulnerable components in liquid argon during a 150 kV high voltage discharge is also demonstrated. Each device is tested for argon contamination and light emission effects, and both are constrained to levels where no significant impact upon liquid argon time projection chamber functionality is expected. Both devices investigated are shown to be suitable for HV surge protection applications in cryogenic detectors.

  8. STORM SURGE INUNDATION SIMULATION OF CYCLON NARGIS WITH A RAINFALL-RUNOFF-INUNDATION MODEL

    NASA Astrophysics Data System (ADS)

    Sayama, Takahiro; Myo Lin, Nay; Fukami, Kazuhiko; Tanaka, Shigenobu; Takeuchi, Kuniyoshi

    Flood inundation caused by cyclone Nargis is simulated on the Irrawaddy delta with a newly developed two-dimensional rainfall-runoff-inundation model. The primary objective of the model is to provide useful information for emergency responses during or at immediately after flood disasters. This study applies the model to simulate the storm surge flooding with the boundary condition of surge water level at the coastal line. The simulated result was compared with an inundation map produced by remote sensing. The reasonable agreement between the simulated and the remotely sensed inundation map confirmed the model reproducibility for storm surge inundations at the large areas. The simulation shows also the importance for considering rainfall-runoff processes for adequate inundation simulations.

  9. Spatio-temporal variations in storm surges along the North Atlantic coasts

    NASA Astrophysics Data System (ADS)

    Marcos, Marta; Woodworth, Philip

    2017-04-01

    Extreme sea levels along the coasts of the North Atlantic Ocean and the Gulf of Mexico have been investigated using hourly tide gauge records compiled in the recently released GESLA-2 data set (www.gesla.org). These regions are among the most densely monitored coasts worldwide, with more than 300 high frequency quality-controlled tide gauge time series available. Here we estimate the storm surge component of extreme sea levels using both tidal residuals and skew surges, for which we explore the spatial and temporal coherency of their intensities, duration and frequency. We quantify the relationship of extremes with dominant large scale climate patterns and discuss the impact of mean sea level changes. Finally, we test the assumption of stationarity of the probability of extreme occurrence and to which extent it holds when mean sea level changes are considered in combination with storm surges.

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

    NASA Astrophysics Data System (ADS)

    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

  11. Simulation of the westward traveling surge and Pi 2 pulsations during substorms

    NASA Technical Reports Server (NTRS)

    Kan, J. R.; Sun, W.

    1985-01-01

    The westward traveling surge and the Pi2 pulsations are simulated as a consequence of an enhanced magnetospheric convection in a model of magnetosphere coupling. The coupling is characterized by the bouncing of Alfven waves launched by the enhanced convection. The reflection of Alfven waves from the ionosphere is treated in which the height-integrated conductivity is allowed to be highly nonuniform and fully anisotropic. The reflection of Alfven waves from the magnetosphere is characterized by the coefficient Rm, depending on whether the field lines are open or closed. The conductivity in the model is self-consistently enhanced with increasing upward field-aligned current density. The results of the simulation, including the convection pattern, the electrojets, the field-aligned current, the conductivity enhancement, the oscillation of the westward electrojet, and the average speed of the westward surge are in reasonable agreement with the features of the westward traveling surge and the Pi 2 pulsations observed during substorms.

  12. Generation of macroscopic magnetic-field-aligned electric fields by the convection surge ion acceleration mechanism

    NASA Technical Reports Server (NTRS)

    Mauk, B. H.

    1989-01-01

    The 'convection surge' model for ion acceleration, designed by Mauk (1986) to explain the observed ion distributions and the field-aligned character of middle magnetospheric ion distributions during the expansion phase of a substorm, was extended to include the self-consistent generation of magnetic-field-aligned electric fields. Results from the modified model show that the convection surge mechanism leads to the generation of dynamical macroscopic magnetic field-aligned electric fields that begin their strongest developments very near the magnetic equator and then propagate to higher latitudes. Potential drops as high as 1 to 10 kV might be expected, depending on the mass species of the ions and on the electron temperatures. It is speculated that the convection surge mechanism could be a key player in the transient field-aligned electromagnetic processes observed to operate within the middle magnetosphere.

  13. The Propagation of a Surge Front on Bering Glacier, Alaska, 2001-2011

    NASA Technical Reports Server (NTRS)

    Turrin, James; Forster, Richard R.; Larsen, Chris; Sauber, Jeanne

    2013-01-01

    Bering Glacier, Alaska, USA, has a 20 year surge cycle, with its most recent surge reaching the terminus in 2011. To study this most recent activity a time series of ice velocity maps was produced by applying optical feature-tracking methods to Landsat-7 ETM+ imagery spanning 2001-11. The velocity maps show a yearly increase in ice surface velocity associated with the down-glacier movement of a surge front. In 2008/09 the maximum ice surface velocity was 1.5 plus or minus 0.017 kilometers per a in the mid-ablation zone, which decreased to 1.2 plus or minus 0.015 kilometers per a in 2009/10 in the lower ablation zone, and then increased to nearly 4.4 plus or minus 0.03 kilometers per a in summer 2011 when the surge front reached the glacier terminus. The surge front propagated down-glacier as a kinematic wave at an average rate of 4.4 plus or minus 2.0 kilometers per a between September 2002 and April 2009, then accelerated to 13.9 plus or minus 2.0 kilometers per a as it entered the piedmont lobe between April 2009 and September 2010. Thewave seems to have initiated near the confluence of Bering Glacier and Bagley Ice Valley as early as 2001, and the surge was triggered in 2008 further down-glacier in the mid-ablation zone after the wave passed an ice reservoir area.

  14. Applicability of Statistical Models of Storm Surge along the U.S. East Coast

    NASA Astrophysics Data System (ADS)

    King, C. A.; Wisniewska, K.; Salmun, H.

    2011-12-01

    Storm surge associated with extratropical storm systems is one of the main factors contributing to inundation of coastal areas along the eastern United States. Both dynamical and statistical models have been used to predict storm surge to provide advance warning of potential for property damage and loss of life. A study presenting a statistical method to determine "storm maximum storm surge" at The Battery, NY, using measurements collected at nearby offshore NOAA buoy concluded that the best predictor of maximum storm surge at The Battery is the storm-composite significant wave height. The present study aims to assess the applicability of this statistical relationship at other locations along the East Coast of the United States. To this end, the statistical method was applied to 15 additional water gauge and buoy pairings along the East Coast of the United States from Portland, ME to Charlotte, SC. In addition to storm-composite significant wave height, several other predictors derived from raw data measured at nearby offshore buoys were examined in the regression analysis. Results confirm the validity of the method for storm surge prediction at other locations. In addition, we investigated the applicability of a specific local model to all other locations along the coast (universal) or to subsets of other locations (regional). Results showed that a universal statistical model is not viable, and that a regional statistical model has some, but limited viability. Factors such as coastline shape and the spatial relationship between water gauges that measure the surge and nearby buoys may play a role in the limitations.

  15. A high resolution study of a hurricane storm surge and inundation in Veracruz, Mexico

    NASA Astrophysics Data System (ADS)

    Díaz García, Ovel; Zavala Hidalgo, Jorge; Douillet, Pascal

    2014-05-01

    Veracruz is the most populated city along the Mexican shoreline of the Gulf of Mexico and also is the country's largest commercial port. In recent years the city has been affected by hurricanes of medium intensity that have provoked human casualties, property damaged and economic loss. Two of the most recent events were hurricane Karl (2010), which caused a storm surge and severe flooding, and hurricane Ernesto (2012). The purpose of this work is to study, based on high-resolution numerical simulations, scenarios of storm surge flooding using state-of-the-art open source numerical models: the Weather, Research and Forecasting (WRF), and the coupled models ADvanced CIRCulation (ADCIRC) and Simulating WAves Nearshore (SWAN) for weather and storm surge hindcast, respectively. We also use topography high resolution data from LIDAR and bathymetry from GEBCO 30", the Mexican Navy and nautical charts from Electrical Federal Commission. We present the validation of the models evaluating several statistical parameters against measurements from Acoustic Data Current Profilers, pressure sensors, tide gauge and meteorological stations for these events. In the case of hurricane Karl, it made landfall 15 km north of Veracruz City, reducing the maximum surge along the city shoreline. The hurricane Ernesto made landfall 200 km southeast of the city, too far to have a significant impact. We did some numerical experiments slightly changing the trajectory, reported by the best track data, for these two hurricanes with the purpose of evaluating storm surge scenarios. The results shows that the worst storm surge cases were when the tracks of this hurricanes made landfall south of the city in the range of 30 to 60 km.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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

  18. Quantification of Storm Surge Using A Python-based ArcGIS Toolbox

    NASA Astrophysics Data System (ADS)

    Gao, S.; Siverd, C. G.; Bilskie, M. V.; Hagen, S. C.; Alizad, K.

    2016-12-01

    Geographic Information System (GIS) technology allows the organization, manipulation, analysis, and visualization of spatial data (Fischer, 2010). Although GIS provides some operations for spatial analysis, the methods are often only partially implemented and can be difficult to find and use effectively (Rigol-Sanchez et al., 2015). For coastal researchers, development of automated GIS tools is essential to efficiently analyze coastal flood risk from hurricanes. An adaptive GIS toolbox, Quantitative Surge Analysis Tool (QSAT), was developed and implements ArcGIS software and Python scripts to quantify attributes of hurricane storm surge (e.g., average water surface elevation). The python script provides a way to allow researchers to reduce the amount of time spent developing common solutions (Etherington, 2010) and repeating manual operations. The QSAT contains tools that run in the ArcGIS program. These tools compute average water surface elevation, average inundation depth, inundated area, total surge volume, percent of land inundated, and retention time for a given polygonal area. A new shapefile is created with a detail attribute table containing the various surge quantities. The toolbox is designed to directly read data files produced by an ADCIRC storm surge simulation as well as a polygon shapefile defining the areas of interest. The functionality of the QSAT toolbox was tested using Hydrologic Unit Code 12 (HUC 12) polygons of coastal Louisiana and ADCIRC model results from a simulation of Hurricane Gustav. The QSAT aids a streamlined transition of surge quantities across a local medium (i.e. HUC 12s) to better inform stakeholders and lead to improved regional and local decisions.

  19. High-resolution Observations of a Large Fan-shaped Surge

    NASA Astrophysics Data System (ADS)

    Li, Zhen; Fang, Cheng; Guo, Yang; Chen, P. F.; Zou, Peng; Cao, Wenda

    2016-08-01

    We present high-resolution observations of a large fan-shaped surge, which was observed on 2013 June 5 with the current largest solar telescope, the 1.6 m New Solar Telescope (NST), at the Big Bear Solar Observatory. The observations are made at TiO, Hα, and 10830 Å wavebands with a spatial resolution better than 0\\buildrel{\\prime\\prime}\\over{.} 1 and a full-run cadence of ˜30 s. The fan-shaped surge consists of many small-scale threads with a typical width of 100 km and a length of up to 200 Mm at the maximum. The threads come from material ejections, which start with a velocity of several km s-1, and then accelerate up to 60-80 km s-1 over six to seven minutes with an acceleration of up to 0.2-0.3 km s-2. The threads can be observed in the Hα band and in SDO/AIA 171 Å images as absorbed objects, implying that they are cool material ejections. The surge is ejected along open magnetic field lines in the extrapolated non-linear force-free field, which might actually be a part of a large-scale magnetic loop stretching back to the solar surface. After 10-20 minutes, the ejections gradually decay and the surge eventually vanishes. The total lifetime is about 35 minutes. The Hα brightening at the root of the fan-shaped surge implies that there is heating in the chromosphere, which could be produced by low-atmosphere interchange magnetic reconnection. Our observation provides evidence of the reconnection model for the fan-shaped surges, which was proposed by Jiang et al.

  20. Changes in winter cold surges over Southeast China: 1961 to 2012

    NASA Astrophysics Data System (ADS)

    Ou, Tinghai; Chen, Deliang; Jeong, Jee-Hoon; Linderholm, Hans W.; Zhou, Tianjun

    2015-02-01

    The present study investigates the overall changes in occurrences of winter cold surges over Southeast China for the period 1961-2012, using instrumental observations, reanalysis and model simulation datasets. Based on objectively defined criteria, cold surges were classified into 3 types according to their dynamical origin as inferred from daily evolution patterns of surface pressure systems with a focus on the Siberian High (SH): type A with an amplification of a quasi-stationary SH associated with high-pressure anomalies over the Ural mountains, type B with a developing SH associated with fast traveling upper-level waves, and type C with a high-pressure originated in the Arctic. Examination of the long-term change in cold surge occurrences shows different interdecadal variations among the 3 types. During 1961-2012, type A events (37.8%) decreased, while type B events, accounting for the majority (52.5%) of total winter cold surges, increased slightly. The contribution by type C to the total occurrence of the cold surges was small (8.8%) compared to that of A and B, but it became more frequent in the latest decade, related to the tendency of the Arctic Oscillation (AO) being more in its negative phase. Overall, we found slightly increased occurrences of cold surges over Southeast China since the early 1980s, despite the weakened SH intensity and warmer mean temperature compared to previous decades. The climate model projections of the phase 5 of the Coupled Model Intercomparison Project (CMIP5) suggests similar trend in the late 21st century under warmer climate.

  1. Health Systems’ “Surge Capacity”: State of the Art and Priorities for Future Research

    PubMed Central

    Watson, Samantha K; Rudge, James W; Coker, Richard

    2013-01-01

    Context Over the past decade, a number of high-impact natural hazard events, together with the increased recognition of pandemic risks, have intensified interest in health systems’ ability to prepare for, and cope with, “surges” (sudden large-scale escalations) in treatment needs. In this article, we identify key concepts and components associated with this emerging research theme. We consider the requirements for a standardized conceptual framework for future research capable of informing policy to reduce the morbidity and mortality impacts of such incidents. Here our objective is to appraise the consistency and utility of existing conceptualizations of health systems’ surge capacity and their components, with a view to standardizing concepts and measurements to enable future research to generate a cumulative knowledge base for policy and practice. Methods A systematic review of the literature on concepts of health systems’ surge capacity, with a narrative summary of key concepts relevant to public health. Findings The academic literature on surge capacity demonstrates considerable variation in its conceptualization, terms, definitions, and applications. This, together with an absence of detailed and comparable data, has hampered efforts to develop standardized conceptual models, measurements, and metrics. Some degree of consensus is evident for the components of surge capacity, but more work is needed to integrate them. The overwhelming concentration in the United States complicates the generalizability of existing approaches and findings. Conclusions The concept of surge capacity is a useful addition to the study of health systems’ disaster and/or pandemic planning, mitigation, and response, and it has far-reaching policy implications. Even though research in this area has grown quickly, it has yet to fulfill its potential to generate knowledge to inform policy. Work is needed to generate robust conceptual and analytical frameworks, along with

  2. Dynamics of wave-current-surge interactions in Lake Michigan: A model comparison

    NASA Astrophysics Data System (ADS)

    Mao, Miaohua; Xia, Meng

    2017-02-01

    Wave, storm surge dynamics, and wave-current-surge interactions (WCSI) were investigated by applying a pair of unstructured-grid-based models to Lake Michigan under two strong wind events. The effects of wind field sources, wind drag coefficient bulk formula, and parameterizations of the bottom friction term were explored to understand lake dynamics. Two wave models were calibrated by using alternative wave physics settings under the 2011 northeasterly wind event. Forced by the southwesterly wind event in 2013, the calibrated models using the atmosphere-ocean fully coupled Climate Forecast System Version 2 wind field were further validated. It is found that the northwesterly winds induced 0.57 m setup near the southwestern coast, whereas the southwesterly winds produced 0.28 m setup and -0.43 m setdown near the northern and southwestern coasts, respectively. The WCSI mostly influence waves and storm surge in shallow-water areas near coasts and islands through depth-induced breaking, current-induced frequency shift and refraction, and wave-induced setup/setdown through wave radiation stress. Owing to the adoption of different discretization algorithms and bottom friction formulations, the modeled storm surge and waves exhibit some variation between the paired models. Even though the storm surge difference with and without WCSI is smaller than that between the two WCSI-coupled models, both circulation models adopt WCSI considering their consistent improvement on model accuracy under both wind events. The analysis of water transport indicates that wind speed, direction, and coastal geometry and bathymetry are also important factors in storm surge.

  3. Availability of a pediatric trauma center in a disaster surge decreases triage time of the pediatric surge population: a population kinetics model

    PubMed Central

    2011-01-01

    Background The concept of disaster surge has arisen in recent years to describe the phenomenon of severely increased demands on healthcare systems resulting from catastrophic mass casualty events (MCEs) such as natural disasters and terrorist attacks. The major challenge in dealing with a disaster surge is the efficient triage and utilization of the healthcare resources appropriate to the magnitude and character of the affected population in terms of its demographics and the types of injuries that have been sustained. Results In this paper a deterministic population kinetics model is used to predict the effect of the availability of a pediatric trauma center (PTC) upon the response to an arbitrary disaster surge as a function of the rates of pediatric patients' admission to adult and pediatric centers and the corresponding discharge rates of these centers. We find that adding a hypothetical pediatric trauma center to the response documented in an historical example (the Israeli Defense Forces field hospital that responded to the Haiti earthquake of 2010) would have allowed for a significant increase in the overall rate of admission of the pediatric surge cohort. This would have reduced the time to treatment in this example by approximately half. The time needed to completely treat all children affected by the disaster would have decreased by slightly more than a third, with the caveat that the PTC would have to have been approximately as fast as the adult center in discharging its patients. Lastly, if disaster death rates from other events reported in the literature are included in the model, availability of a PTC would result in a relative mortality risk reduction of 37%. Conclusions Our model provides a mathematical justification for aggressive inclusion of PTCs in planning for disasters by public health agencies. PMID:21992575

  4. Possible management of near shore nonlinear surging waves through bottom boundary conditions

    NASA Astrophysics Data System (ADS)

    Mukherjee, Abhik; Janaki, M. S.; Kundu, Anjan

    2017-03-01

    We propose an alternative way for managing near shore surging waves, including extreme waves like tsunamis, going beyond the conventional passive measures like the warning system. We study theoretically the possibility of influencing the nonlinear surface waves through a leakage boundary effect at the bottom. It has been found through analytic result, that the controlled leakage at the bottom might regulate the amplitude of the surface solitary waves. This could lead to a possible decay of the surging waves to reduce its hazardous effects near the shore. Our theoretical results are estimated by applying it to a real coastal bathymetry of the Bay of Bengal in India.

  5. Overview of Rotating Cavitation and Cavitation Surge in the Fastrac Engine LOX Turbopump

    NASA Technical Reports Server (NTRS)

    Zoladz, Thomas; Turner, Jim (Technical Monitor)

    2001-01-01

    Observations regarding rotating cavitation and cavitation surge experienced during the development of the Fastrac 60 Klbf engine turbopump are discussed. Detailed observations from the analysis of both water flow and liquid oxygen test data are offered. Scaling and general comparison of rotating cavitation between water flow and liquid oxygen testing are discussed. Complex data features linking the localized rotating cavitation mechanism of the inducer to system surge components are described in detail. Finally a description of a simple lumped-parameter hydraulic system model developed to better understand observed data is given.

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

    NASA Astrophysics Data System (ADS)

    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.

  7. Winter speed-up during a quiescent phase of surge-type glaciers: observations and implications

    NASA Astrophysics Data System (ADS)

    Abe, T.; Furuya, M.

    2014-12-01

    Glacier surface velocity is a combination of the internal deformation of ice and basal slip (including till deformation overlying bedrock) (Cuffey and Paterson, 2010). Short-term velocity changes can be attributed to basal slip associated with water pressure changes because of both the seasonal meltwater input and the evolution of the englacial and subglacial hydrological system. Thus, examining the velocity changes with high spatial and temporal resolution is helpful to understand how subglacial conditions evolve and control the surface velocities. We examined spatial and temporal velocity changes at quiescent surge-type glaciers near the border of Alaska/Yukon by SAR offset tracking and found significant acceleration from fall to winter regardless of surge events. Moreover, whereas the upstream propagating summer speed-up was observed, the winter speed-up propagated from upstream to downstream. Lingle and Fatland (2003) proposed the englacial water storages as the fundamental driver of temperate-glacier surge. Although our observations were performed at the quiescent and rather poly-thermal than temperate surge-type glaciers, our observations also support the englacial water storage hypothesis. Namely, the englacial water storages that do not directly connect to the surface can promote basal sliding through increased water pressure as winter approaches. Glacier surge often initiates in winter (Raymond, 1987), which has been explained by creep closure of efficient drainage system in fall and subsequent higher water pressure in winter. Mini-surges are also known in this area, and have been interpreted in a similar mechanism. However, in order to maintain the higher water pressure for some time period in winter, there should be such sources that can keep supplying the water to the bed. It has been uncertain, however, if, how and where the water can be stored in winter. Also, we should keep in mind that many of the previously known mini-surges were actually occurring

  8. Surge dynamics coupled to pore-pressure evolution in debris flows

    USGS Publications Warehouse

    Savage, S.B.; Iverson, R.M.; ,

    2003-01-01

    Temporally and spatially varying pore-fluid pressures exert strong controls on debris-flow motion by mediating internal and basal friction at grain contacts. We analyze these effects by deriving a one-dimensional model of pore-pressure diffusion explicitly coupled to changes in debris-flow thickness. The new pore-pressure equation is combined with Iverson's (1997) extension of the depth-averaged Savage-Hutter (1989, 1991) granular avalanche equations to predict motion of unsteady debris-flow surges with evolving pore-pressure distributions. Computational results illustrate the profound effects of pore-pressure diffusivities on debris-flow surge depths and velocities. ?? 2003 Millpress,.

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

    NASA Astrophysics Data System (ADS)

    Caro, C. V. C.; Santiago, J. T.; Suarez, J. K. B.; Tablazon, J. P.; Dasallas, L. L.; Lagmay, A. M. F. A.

    2015-12-01

    Being located in north pacific basin which is the most active region of cyclogenesis in the world, the Philippines is frequently visited by tropical cyclones (TC). An average of 20 TC per year enter the Philippine area of responsibility (PAR), around 9 of which make landfall. Tropical cyclone enhances monsoons which cause heavy rainfall, bring in strong winds that are capable of destroying properties. This strong wind also causes storm surges that inundate the coastal portions of the country. Typhoon Haiyan is one of the most recent and devastating events, which left the Philippines with 6,293 deaths and 2 billion USD worth of damages. In this regard, the Department of Science and Technology - Nationwide Operational Assessment of Hazards (DOST - Project NOAH) started a project to quantify, identify and map the storm surge hazards in the country. The Japan Meteorological Agency (JMA) storm surge model is used to simulate 721 TCs that enter PAR. The JMA storm surge model yields time series plots for each observation point that has been defined by the team. Maximum tide levels are identified using the WXtide software, and are added to the resulting storm surge time series for each observation point. The storm tide levels are then categorized into 4 groups which is based on its peak height, this is done to create a storm surge advisory (SSA) based on the probable storm tide height. The 4 groups are SSA 1 (0.01m to 2m), SSA 2 (2.01m to 3m), SSA 3 (3.01m to 4m), and SSA 4 (4m and above). A time series plot for each advisory is used as an input data in Flo2D flood modelling software. This software is a grid developer system software that has maps with topographies and creates models based on the grid topographies, boundaries, and tides. This modelling software can produce the probable extent,depth of inundation and its corresponding hazard level of storm surge. The storm surge advisory improves the capabilities of the country in mitigating disasters. Through this advisory

  10. Importance of wave age and resonance in storm surges: The case Xynthia, Bay of Biscay

    NASA Astrophysics Data System (ADS)

    Bertin, Xavier; Bruneau, Nicolas; Breilh, Jean-François; Fortunato, André B.; Karpytchev, Mikhail

    This study aims to hindcast and analyze the storm surge associated with Xynthia, a mid-latitude depression that severely hit the French central part of the Bay of Biscay on the 27-28th of February 2010. The main losses in human lives and damages were caused by the associated storm surge, which locally exceeded 1.5 m and peaked at the same time as a high spring tide, causing the flooding of low-lying coasts. A new storm surge modeling system was developed, based on the unstructured-grid circulation model SELFE and the spectral wave model WaveWatchIII. The modeling system was implemented over the North-East Atlantic Ocean and resulted in tidal and wave predictions with errors of the order of 3% and 15%, respectively. The storm surge associated with Xynthia was also well predicted along the Bay of Biscay, with only a slight underestimation of the surge peak by 3-8%. Numerical experiments were then performed to analyze the physical processes controlling the development of the storm surge and revealed firstly that the wind caused most of the water level anomaly through an Ekman setup process. The comparison between a wave-dependant and a quadratic parameterization to compute wind stress showed that the storm surge was strongly amplified by the presence of steep and young wind-waves, related to their rapid development in the restricted fetch of the Bay of Biscay. In the central part of the Bay of Biscay, both observed and predicted water level anomalies at landfall displayed ˜6 h oscillations, with amplitudes of up to 0.2 m (10-20% of the surge peak). An analytical shelf resonance model and numerical experiments demonstrated that the period of the observed oscillations corresponds to the resonant mode of the continental shelf in the central part of the Bay of Biscay. It is concluded that these oscillations originate from the interactions between the water level perturbation and the continental shelf and this phenomenon is expected to be relevant at other places along

  11. High intensity surge and seasonal effects in the dark current of the Nimbus-4 BUV experiment

    NASA Technical Reports Server (NTRS)

    Stassinopoulos, E. G.; Goldberg, R. A.; Vette, J. I.; Felton, L. L.

    1981-01-01

    Seasonal global maps of the dark current produced by corpuscular radiation contributing to the background level of the Nimbus-4 Backscattered Ultraviolet (BUV) instrument were developed, using BUV monochrometer nighttime data in the pulse counting mode during solar and magnetically quiet periods. The existence of high intensity surges has been discovered which occur on a sporadic basis and which cause sufficient enhancements of dark current within the subauroral regions to produce background levels similar to those within the South Atlantic anomaly. Examples are provided of the nominal quiet dark current intensity maps, and the variability and implications of the surge data are discussed.

  12. Observations on Rotating Cavitation and Cavitation Surge from the Development of the Fastrac Engine Turbopump

    NASA Technical Reports Server (NTRS)

    Zoladz, Thomas F.

    2000-01-01

    Observations regarding rotating cavitation and cavitation surge experienced during the development of the Fastrac engine turbopump are discussed. Detailed observations acquired from the analysis of both water flow and liquid oxygen test data are offered in this paper. Scaling and general comparison of rotating cavitation between water flow and liquid oxygen testing are discussed. Complex data features linking the localized rotating cavitation mechanism of the inducer to system surge components are described in detail. Finally a description of a lumped-parameter hydraulic system model developed to better understand observed data is given.

  13. Effects of seismic surge waves and implications for moraine-dammed lake outburst

    NASA Astrophysics Data System (ADS)

    Du, Cui; Yao, Lingkan; Huang, Yidan; Yan, Jiahong; Shakya, Subhashsagar

    2016-09-01

    Moraine dams usually collapse due to overtopping by the surge wave in the dammed lake, and the surge wave is most likely caused by an earthquake. The seismic water wave (SWW) is a major factor causing the dam to break in the earthquake zone. This paper focused on the SWW by model experiments with a shaking water tank under conditions of various water depths, seismic waves, and peak ground accelerations. Two empirical equations were obtained for estimating maximal wave height for the low and high frequency, respectively. Finally, we present the application of the empirical equations on Midui Glacier Lake in Tibet plateau.

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

    NASA Astrophysics Data System (ADS)

    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.

  15. The “Ram Effect”: A “Non-Classical” Mechanism for Inducing LH Surges in Sheep

    PubMed Central

    Fabre-Nys, Claude; Chanvallon, Audrey; Dupont, Joëlle; Lardic, Lionel; Lomet, Didier; Martinet, Stéphanie; Scaramuzzi, Rex J.

    2016-01-01

    During spring sheep do not normally ovulate but exposure to a ram can induce ovulation. In some ewes an LH surge is induced immediately after exposure to a ram thus raising questions about the control of this precocious LH surge. Our first aim was to determine the plasma concentrations of oestradiol (E2) E2 in anoestrous ewes before and after the “ram effect” in ewes that had a “precocious” LH surge (starting within 6 hours), a “normal” surge (between 6 and 28h) and “late» surge (not detected by 56h). In another experiment we tested if a small increase in circulating E2 could induce an LH surge in anoestrus ewes. The concentration of E2 significantly was not different at the time of ram introduction among ewes with the three types of LH surge. “Precocious” LH surges were not preceded by a large increase in E2 unlike “normal” surges and small elevations of circulating E2 alone were unable to induce LH surges. These results show that the “precocious” LH surge was not the result of E2 positive feedback. Our second aim was to test if noradrenaline (NA) is involved in the LH response to the “ram effect”. Using double labelling for Fos and tyrosine hydroxylase (TH) we showed that exposure of anoestrous ewes to a ram induced a higher density of cells positive for both in the A1 nucleus and the Locus Coeruleus complex compared to unstimulated controls. Finally, the administration by retrodialysis into the preoptic area, of NA increased the proportion of ewes with an LH response to ram odor whereas treatment with the α1 antagonist Prazosin decreased the LH pulse frequency and amplitude induced by a sexually active ram. Collectively these results suggest that in anoestrous ewes NA is involved in ram-induced LH secretion as observed in other induced ovulators. PMID:27384667

  16. The luteinizing hormone surge is preceded by an estrogen-induced increase of hypothalamic progesterone in ovariectomized and adrenalectomized rats.

    PubMed

    Micevych, Paul; Sinchak, Kevin; Mills, Richard H; Tao, Leslie; LaPolt, Philip; Lu, John K H

    2003-07-01

    As circulating estrogen levels rise on the afternoon of proestrus, they stimulate the hypothalamo-pituitary axis. This estrogen positive feedback is pivotal to stimulate the luteinizing hormone (LH) surge required for ovulation and luteinization of ovarian follicles. In addition to estrogen, pre-LH surge progesterone is critical for an LH surge as was demonstrated by blocking progesterone synthesis. In ovariectomized (OVX) rats treated with trilostane, a blocker of the enzyme 3beta-hydroxysteroid dehydrogenase (3beta-HSD) that catalyzes the conversion of pregnenolone to progesterone, estrogen did not induce an LH surge. Further, estrogen induced an LH surge in OVX and adrenalectomized (ADX) rats, indicating that the source of progesterone was neither the ovary nor adrenal gland. This estrogen-only LH surge was inhibited by pretreatment with trilostane, indicating that although the adrenal gland and ovary were not necessary for positive feedback, progesterone synthesis was critical for estrogen-induced positive feedback in an OVX/ADX rat. This suggested that the LH surge is dependent on the pre-LH surge synthesis of progesterone. Estrogen-induced progesterone receptors in the hypothalamus are vital for the LH surge, so a potential location for progesterone synthesis is the hypothalamus. OVX/ADX female rats were treated with 17beta-estradiol (50 microg) and progesterone levels were assayed by RIA. Progesterone levels were elevated in hypothalamic tissue following estrogen treatment. No increases in tissue progesterone levels were found in parietal cortex, cerebellum, medulla, pituitary or plasma. Additionally, male rats that do not have an estrogen positive feedback-induced LH surge were examined. Castrated/ADX male rats had no increase in hypothalamic progesterone levels after estrogen treatment. Together, these data strongly suggest that estrogen enhances neuroprogesterone synthesis in the hypothalamus that is involved in the positive feedback regulating the LH

  17. Adapting NEMO for use as the UK operational storm surge forecasting model

    NASA Astrophysics Data System (ADS)

    Furner, Rachel; Williams, Jane; Horsburgh, Kevin; Saulter, Andrew

    2016-04-01

    The United Kingdom is an area vulnerable to damage due to storm surges, particularly the East Coast which suffered losses estimated at over £1 billion during the North Sea surge event of the 5th and 6th December 2013. Accurate forecasting of storm surge events for this region is crucial to enable government agencies to assess the risk of overtopping of coastal defences so they can respond appropriately, minimising risk to life and infrastructure. There has been an operational storm surge forecast service for this region since 1978, using a numerical model developed by the National Oceanography Centre (NOC) and run at the UK Met Office. This is also implemented as part of an ensemble prediction system, using perturbed atmospheric forcing to produce an ensemble surge forecast. In order to ensure efficient use of future supercomputer developments and to create synergy with existing operational coastal ocean models the Met Office and NOC have begun a joint project transitioning the storm surge forecast system from the current CS3X code base to a configuration based on the Nucleus for European Modelling of the Ocean (NEMO). This work involves both adapting NEMO to add functionality, such as allowing the drying out of ocean cells and changes allowing NEMO to run efficiently as a two-dimensional, barotropic model. As the ensemble surge forecast system is run with 12 members 4 times a day computational efficiency is of high importance. Upon completion this project will enable interesting scientific comparisons to be made between a NEMO based surge model and the full three-dimensional baroclinic NEMO based models currently run within the Met Office, facilitating assessment of the impact of baroclinic processes, and vertical resolution on sea surface height forecasts. Moving to a NEMO code base will also allow many future developments to be more easily used within the storm surge model due to the wide range of options which currently exist within NEMO or are planned for

  18. Potential Effects of SLR and Land-Cover Changes on Hurricane Surge and Damage

    NASA Astrophysics Data System (ADS)

    Ferreira, C.; Irish, J. L.; Olivera, F.

    2012-12-01

    Hurricanes are one of the most costly natural disasters impacting US coastal areas. Recent studies point towards an increase in damages caused by hurricanes, resulting from sea-level rise (SLR), possible hurricane intensification due to a warmer climate and increasing coastal populations. The SLR is one of the most significant factors of climate change that will impact coastal areas. Besides geometrical changes in coastal bays (i.e., deeper water depth and larger surface area), SLR is also expected to have substantial impacts on the patterns and process of coastal wetlands, thereby affecting surge generation and propagation inside the bays. We analyzed the impacts of SLR on hurricane storm surges, structural building damage, and population and businesses affected for coastal bays located on the Texas central coast. To evaluate the effects of SLR on surges, we considered its impacts on changes in land cover and bay geometry caused by SLR. The analyses were conducted using the hydrodynamic model ADCIRC and a wind and pressure field model (PBL) representing the physical properties of historical hurricane Bret and hypothetical storms. The effects of land cover change were represented within ADCIRC by the changes in the frictional drag at the sea bottom and changes in momentum transfer from the wind to the water column caused by vegetation losses. Simulations were performed using a high-resolution unstructured numerical mesh to study surge response in communities along the coastal bays of Texas. First, we evaluated the impacts of land cover changes due to SLR on the surge response. Second, we evaluated the impacts of neglecting land cover changes due to SLR on the surge response. Finally, we evaluated the overall effect of SLR on the mean maximum surge and the consequent extent of the flooded areas. Although the overall impacts of SLR on surge (water elevation above mean water level) are highly dependent on storm conditions and specific locations within the study area

  19. Phase II Report for SERRI Project No. 80037: Investigation of surge and wave reduction by vegetation (Phase II)

    USDA-ARS?s Scientific Manuscript database

    To better understand and quantify the effectiveness of wetland vegetation in mitigating the impact of hurricane and storm surges, this SERRI project (No. 80037) examined surge and wave attenuation by vegetation through laboratory experiments, field observations and computational modeling. It was a c...

  20. 40 CFR Table 2 to Subpart H of... - Surge Control Vessels and Bottoms Receivers at Existing Sources

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 9 2010-07-01 2010-07-01 false Surge Control Vessels and Bottoms Receivers at Existing Sources 2 Table 2 to Subpart H of Part 63 Protection of Environment ENVIRONMENTAL... Equipment Leaks Pt. 63, Subpt. H, Table 2 Table 2 to Subpart H of Part 63—Surge Control Vessels and Bottoms...

  1. 40 CFR Table 3 to Subpart H of... - Surge Control Vessels and Bottoms Receivers at New Sources

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 9 2010-07-01 2010-07-01 false Surge Control Vessels and Bottoms Receivers at New Sources 3 Table 3 to Subpart H of Part 63 Protection of Environment ENVIRONMENTAL... Equipment Leaks Pt. 63, Subpt. H, Table 3 Table 3 to Subpart H of Part 63—Surge Control Vessels and Bottoms...

  2. 40 CFR Table 2 to Subpart H of... - Surge Control Vessels and Bottoms Receivers at Existing Sources

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 9 2011-07-01 2011-07-01 false Surge Control Vessels and Bottoms Receivers at Existing Sources 2 Table 2 to Subpart H of Part 63 Protection of Environment ENVIRONMENTAL... Equipment Leaks Pt. 63, Subpt. H, Table 2 Table 2 to Subpart H of Part 63—Surge Control Vessels and Bottoms...

  3. 40 CFR Table 3 to Subpart H of... - Surge Control Vessels and Bottoms Receivers at New Sources

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 9 2011-07-01 2011-07-01 false Surge Control Vessels and Bottoms Receivers at New Sources 3 Table 3 to Subpart H of Part 63 Protection of Environment ENVIRONMENTAL... Equipment Leaks Pt. 63, Subpt. H, Table 3 Table 3 to Subpart H of Part 63—Surge Control Vessels and Bottoms...

  4. The climatology of East Asian winter monsoon and cold surges from 1979--1995 NCEP/NCAR reanalyses

    SciTech Connect

    Yi Zhang; Sperber, K.; Boyle, J.

    1996-04-01

    The East Asian winter monsoon, which is associated with the Siberian high and active cold surges, is one of the most energetic monsoon circulation systems. The dramatic shift of northeasterlies and the outbreak of cold surges dominate the winter weather and local climate in the East Asian region, and may exert a strong impact on the extratropical and tropical planetary-scale circulations and influence the SSTs in the tropical western Pacific. General characteristics of the winter monsoon and cold surges and their possible link with tropical disturbances are revealed in many observational studies. Little attention has been given to the climatological aspects of th