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Sample records for plast reconstr surg

  1. 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

  2. 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.

  3. 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.

  4. 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

  5. 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

  6. Reinnervation of Paralyzed Muscle by Nerve-Muscle-Endplate Band Grafting

    DTIC Science & Technology

    2015-10-01

    deficits. Plast Reconstr Surg. 2000;105(6):2003- 2009. 49. Goding GS Jr, Cummings CW, Bright DA. Extension of neuromuscular pedicles and direct nerve...Majed AA, Neumann CM, Brushart TM, Gordon T. Brief electrical stimulation promotes the speed and accuracy of motor axonal regeneration. J Neurosci... CT S.A. LeMaire, MD Editor of the Journal of Surgical Research Baylor College of Medicine, Houston, Texas, USA Dear Drs. McFadden and

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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...

  19. 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…

  20. 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.

  1. 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.

  2. 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.

  3. 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?

  4. 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...

  5. 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...

  6. 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

  7. 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).

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. '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.

  14. 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.

  15. 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

  16. 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

  17. 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.

  18. Exercising Tactically for Taming Postmeal Glucose Surges

    PubMed Central

    Chacko, Elsamma

    2016-01-01

    This review seeks to synthesize data on the timing, intensity, and duration of exercise found scattered over some 39 studies spanning 3+ decades into optimal exercise conditions for controlling postmeal glucose surges. The results show that a light aerobic exercise for 60 min or moderate activity for 20–30 min starting 30 min after meal can efficiently blunt the glucose surge, with minimal risk of hypoglycemia. Exercising at other times could lead to glucose elevation caused by counterregulation. Adding a short bout of resistance exercise of moderate intensity (60%–80%  VO2max) to the aerobic activity, 2 or 3 times a week as recommended by the current guidelines, may also help with the lowering of glucose surges. On the other hand, high-intensity exercise (>80%  VO2max) causes wide glucose fluctuations and its feasibility and efficacy for glucose regulation remain to be ascertained. Promoting the kind of physical activity that best counters postmeal hyperglycemia is crucial because hundreds of millions of diabetes patients living in developing countries and in the pockets of poverty in the West must do without medicines, supplies, and special diets. Physical activity is the one tool they may readily utilize to tame postmeal glucose surges. Exercising in this manner does not violate any of the current guidelines, which encourage exercise any time. PMID:27073714

  19. 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)

  20. 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

  1. Industrial Strength Defense: A Disquisition on Manufacturing, Surge and War

    DTIC Science & Technology

    1990-01-01

    Costs iii Specifics of Surge Investments Rocket Motors Microwave Devices Gyroscopes, Accelerometers, and ARAs Target Detection Devices Seekers Test...Force on Industrial Readiness (TFIRE) o An official JCS paper defining production surge and discussing methods for ranking surge projects o A survey of...meet the higher production rates of surge. 19 (Another method , which would have cut costs in half, also could have been used. This would have been to

  2. 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

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. Regional Mass Fatality Management in Pandemic Surge

    DTIC Science & Technology

    2008-12-01

    cremations , and entombments conducted in an average year per funeral director was around 150, with the total number of statewide on-site storage...supplies or pre-identifying temporary mass burial sites and cremation arrangements for death surge, emergency management directors do not believe that...burial sites or alternate cremation operations and another 26% cannot say one way or the other whether this has occurred. Neither are they confident

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. 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.

  18. 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.

  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. 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.

  2. 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

  3. 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.

  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. 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

  6. 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.

  7. 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...

  8. 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...

  9. 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.

  10. 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.

  11. 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

  12. 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

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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

  3. 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

  4. 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

  5. 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

  6. 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 ...

  7. 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 ...

  8. 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.

  9. 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.

  10. 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

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Switching-surge characteristics of high-phase-order lines

    SciTech Connect

    1982-03-01

    High phase order (HPO) is the use of more than the conventional three phases for electric power transmission. A previous study evaluated the general feasibility of the HPO concept and defined the need for design information in specific areas, including the need for switching surge data. This study was undertaken to obtain switching surge characteristics applicable to a broad spectrum of utility system applications, thereby supplying data for practical HPO design, and to obtain detailed data on switching surges to define test parameters for HPO testing and insulation system design. Both objectives were met, and voltage magnitude data for 6- and 12-phase systems are presented and compared with 3-0 systems. (LCL)

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. 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,…

  6. 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

  7. 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

  8. 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

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. 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

  9. 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

  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. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. 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.).

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  3. 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.

  4. 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.

  5. 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.

  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. 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.

  8. 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.

  9. 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.

  10. 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

  11. 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

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Hurricane Sandy storm surges observed by HY-2A satellite altimetry and tide gauges

    NASA Astrophysics Data System (ADS)

    Chen, Nan; Han, Guoqi; Yang, Jingsong; Chen, Dake

    2014-07-01

    Hurricane Sandy made landfall to the northeast of Atlantic City, New Jersey at 23:30 UTC on 29 October 2012 and caused large storm surges and devastating flooding along the New Jersey and New York coasts. Here we combine sea surface height measurements from the HaiYang-2A (HY-2A) satellite altimeter with coastal tide-gauge data to study the features of the Hurricane Sandy storm surges. The HY-2A altimeter captured the cross-shelf profile of surge at the time of Sandy's peak surge, with a surge magnitude of about 1.83 m at the coast and a cross-shelf decaying scale of 68 km. The altimetric surge magnitude agrees approximately with tide-gauge estimate of 1.73 m at nearby Montauk. Further analysis suggests that continental shelf waves were generated during the passage of Sandy. The continental shelf wave observed by altimetry has a propagating speed of 6.5 m/s. The post landfall free shelf wave at Atlantic City observed by tide gauges has a propagating phase speed of 6.8 m/s and cross-shelf e-folding scale of 75 km. In contrast, the post landfall sea level oscillation at Montauk is not associated with a continental shelf wave. The study indicates that satellite altimetry is capable of observing and useful for understanding features of storm surges, complementing existing coastal tide gauges.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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...

  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. 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 ...

  16. 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

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. Coastal Storm Surge Analysis System Digital Elevation Model: Report 1: Intermediate Submission No. 1.1

    DTIC Science & Technology

    2011-03-01

    the development and application of a state - of - the - art storm surge risk assessment capability for the FEMA Region III domain which...within the states of Virginia, Maryland, and Delaware, and the District of Columbia including the Atlantic Ocean, Chesapeake Bay and its tributaries...to calculate the combined effects of surge and wind -induced waves. A seamless modeling grid was developed to support the

  6. 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.

  7. 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.

  8. 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.

  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. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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

  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 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

  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. 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

  4. 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

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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

  13. 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

  14. 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

  15. 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

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. 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

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  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. 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

  17. 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

  18. 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

  19. 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.

  20. 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

  1. 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

  2. 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

  3. 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.

  4. 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,.

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. 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

  11. 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

  12. Phase II Report for SERRI Project No. 80037: Investigation of surge and wave reduction by vegetation (Phase II)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  13. 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 the winter monsoon and cold surges. The purpose of this study is to compile and document the East Asian mean winter circulation, and present the climatology of cold surges and the Siberian high based on the 1979--1995 NCEP/NCAR reanalyses. Of particular interest is the interannual variation of winter monsoon circulation and cold surge events. Given that the cold surge activity and the Indonesian convection are much reduced during the 1982--83 period, one of the goals is to determine whether there exists a statistically significant relationship between ENSO and the interannual variation of winter monsoon and cold surges.

  14. Evaluation of U.S. Navy Tropical Cyclone Storm Surge Requirements in the Western North Pacific and Indian Oceans.

    DTIC Science & Technology

    1983-02-01

    NAVENVPREDRSCHFAC Technical Report TR 77-03, 284 pp. c. Choi , B.H., 1980: Tidal Analysis of Inchon for the Years 1962-1972/1975-1977, KORDI Report 80-01. d. Hwang, C...Seoul, Korea, Hydro- graphic records and storm surge data. g. Chu, K.S., Personal storm surge data and calculations. h. Ahn, Myong- Bok , Personal storm

  15. Development of Outlier detection Algorithm Applicable to a Korean Surge-Gauge

    NASA Astrophysics Data System (ADS)

    Lee, Jun-Whan; Park, Sun-Cheon; Lee, Won-Jin; Lee, Duk Kee

    2016-04-01

    The Korea Meteorological Administration (KMA) is operating a surge-gauge (aerial ultrasonic type) at Ulleung-do to monitor tsunamis. And the National Institute of Meteorological Sciences (NIMS), KMA is developing a tsunami detection and observation system using this surge-gauge. Outliers resulting from a problem with the transmission and extreme events, which change the water level temporarily, are one of the most common discouraging problems in tsunami detection. Unlike a spike, multipoint outliers are difficult to detect clearly. Most of the previous studies used statistic values or signal processing methods such as wavelet transform and filter to detect the multipoint outliers, and used a continuous dataset. However, as the focus moved to a near real-time operation with a dataset that contains gaps, these methods are no longer tenable. In this study, we developed an outlier detection algorithm applicable to the Ulleung-do surge gauge where both multipoint outliers and missing data exist. Although only 9-point data and two arithmetic operations (plus and minus) are used, because of the newly developed keeping method, the algorithm is not only simple and fast but also effective in a non-continuous dataset. We calibrated 17 thresholds and conducted performance tests using the three month data from the Ulleung-do surge gauge. The results show that the newly developed despiking algorithm performs reliably in alleviating the outlier detecting problem.

  16. STEAM PLANT, TRA609. MEZZANINE LAYOUT. PIPE TRENCH AND SURGE TANK ...

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

    STEAM PLANT, TRA-609. MEZZANINE LAYOUT. PIPE TRENCH AND SURGE TANK PIT. BLAW-KNOX 3150-9-3, 6/1950. INL INDEX NO. 531-0609-00-098-100019, REV. 0. - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

  17. Tropical storm tracks in a global tide and storm surge reanalysis

    NASA Astrophysics Data System (ADS)

    Verlaan, Martin; Winsemius, Hessel; Vatvani, Deepak; Muis, Sanne; Ward, Philip

    2016-04-01

    Flooding due to tides and storm surges causes massive societal impacts and the largest economic damage of all flood hazards. To adequately estimate and counteract upon their risk, sound global scientific information on hazards due to storm surges and tides is required. Recently, a first global tide and storm surge reanalysis (GTSR) has been prepared (Muis et al., 2015) that provides a 36 year time series of sea levels, along with extreme value statistics. The GTSR is established using a physically based model, forced by meteorological reanalysis data. Validation of GTSR showed that tropical storms are underrepresented, firstly, due to the fact that they occur rarely and then only affect a limited area, and secondly, because the spatio-temporal resolution of reanalysis wind and pressure fields is too low to accurately represent the strong spatio-temporal variability of tropical storms. In this contribution, we show the GTSR as well as its recent advancements by contributing a large amount of historical tropical storm tracks into the analysis. This advancement is seen as a first step to accommodate tropical storms in the reanalysis. We estimate how the statistics of the meteorological extremes in pressure and wind are changing, and consequently, how this translates into new statistics of storm surge extremes.

  18. Tropical Storm Track representation in a Global Tide and Storm Surge Reanalysis

    NASA Astrophysics Data System (ADS)

    Winsemius, H.; Verlaan, M.; Vatvani, D.; Muis, S.; Ward, P.

    2015-12-01

    Flooding due to tides and storm surges causes massive societal impacts and the largest economic damage of all flood hazards. To adequately estimate and counteract upon their risk, sound global scientific information on hazards due to storm surges and tides is required. Recently, a first global tide and storm surge reanalysis (GTSR) has been prepared (Muis et al., 2015) that provides a 36 year time series of sea levels, along with extreme value statistics. The GTSR is established using a physically based model, forced by meteorological reanalysis data. Validation of GTSR showed that tropical storms are underrepresented, firstly, due to the fact that they occur rarely and then only affect a limited area, and secondly, because the spatio-temporal resolution of reanalysis wind and pressure fields is too low to accurately represent the strong spatio-temporal variability of tropical storms. In this contribution, we are improving GTSR by contributing a large amount of historical tropical storm tracks into the analysis as a first step to accommodate tropical storms in the reanalysis. We estimate how the statistics of the meteorological extremes in pressure and wind are changing, and consequently, how this translates into new statistics of storm surge extremes.

  19. Use of the Colorado SURGE System for Continuing Education for Civil Engineers.

    ERIC Educational Resources Information Center

    Fead, J. W. N.

    The Colorado State University Resources in Graduate Education (SURGE) program is described in this report. Since it is expected that not all the participants in a graduate engineering program will be able to attend university-based lectures, presentations are video-taped and transported to industrial plants, engineering offices, and other…

  20. Observed triggering of tropical convection by a cold surge: Implications for MJO initiation

    NASA Astrophysics Data System (ADS)

    Wang, L.; Kodera, K.; Chen, W.

    2012-04-01

    The extratropical influence is an important mechanism in the initiation of the Madden-Julian Oscillation (MJO). Based on analyses of several datasets, this study demonstrates that the MJO case initiated in late January 2008 was strengthened by a preceding cold surge over West Asia when the MJO was at its initiation phase. The cold surge-related northerlies propagated southward along the east coast of African continent. The associated convergence on its edge enhanced ascending motion in the tropical western Indian Ocean and led to the onset of deep convection to the north of Madagascar. This process helped to amplify the MJO convection rapidly as shown in the development of the moist static energy anomalies. In this way, the cold surge affected the behavior of the MJO and modified the timing of its initiation to some extent. These results support previous studies that the extratropical factors are important for the initiation of the MJO, and imply that the subtropical cold surges are more likely to strengthen and accelerate the buildup of deep MJO convection rather than to initiate it.

  1. Current & future vulnerability of sarasota county Florida to hurricane storm surge & sea level rise

    USGS Publications Warehouse

    Frazier, T.; Wood, N.; Yarnal, B.

    2008-01-01

    Coastal communities in portions of the United States are vulnerable to storm-surge inundation from hurricanes and this vulnerability will likely increase, given predicted rises in sea level from climate change and growing coastal development. In this paper, we provide an overview of research to determine current and future societal vulnerability to hurricane storm-surge inundation and to help public officials and planners integrate these scenarios into their long-range land use plans. Our case study is Sarasota County, Florida, where planners face the challenge of balancing increasing population growth and development with the desire to lower vulnerability to storm surge. Initial results indicate that a large proportion of Sarasota County's residential and employee populations are in areas prone to storm-surge inundation from a Category 5 hurricane. This hazard zone increases when accounting for potential sea-level-rise scenarios, thereby putting additional populations at risk. Subsequent project phases involve the development of future land use and vulnerability scenarios in collaboration with local officials. Copyright ASCE 2008.

  2. An Investigation of Surge in a High-Speed Centrifugal Compressor Using Digital PIV

    NASA Technical Reports Server (NTRS)

    Wernet, Mark P.; Bright, Michelle M.; Skoch, Gary J.

    2001-01-01

    Compressor stall is a catastrophic breakdown of the flow in a compressor, which con lead to a loss of engine power, large pressure transients in the inlet/nacelle, and engine flameout. The implementation of active or passive strategies for controlling rotating stall and surge can significantly extend the stable operating range of a compressor without substantially sacrificing performance. It is crucial to identify the dynamic changes occurring in the flow field prior to rotating stall and surge in order to control these events successfully. Generally, pressure transducer measurements are made to capture the transient response of a compressor prior to rotating stall. In this investigation, Digital Particle Imaging Velocimetry (DPIV) is used in conjunction with dynamic pressure transducers to capture transient velocity and pressure measurements simultaneously in the nonstationary flow field during compressor surge. DPIV is an instantaneous, planar measurement technique that is ideally suited for studying transient flow phenomena in highspeed turbomachinery and has been used previously to map the stable operating point flow field in the diffuser of a high-speed centrifugal compressor. Through the acquisition of both DPIV images and transient pressure data, the time evolution of the unsteady flow during surge is revealed.

  3. An Investigation of Surge in a High-Speed Centrifugal Compressor Using Digital PIV

    NASA Technical Reports Server (NTRS)

    Wernet, Mark P.; Bright, Michelle M.; Skoch, Gary J.

    2002-01-01

    Compressor stall is a catastrophic breakdown of the flow in a compressor, which can lead to a loss of engine power, large pressure transients in the inlet/nacelle and engine flameout. The implementation of active or passive strategies for controlling rotating stall and surge can significantly extend the stable operating range of a compressor without substantially sacrificing performance. It is crucial to identify the dynamic changes occurring in the flow field prior to rotating stall and surge in order to successfully control these events. Generally, pressure transducer measurements are made to capture the transient response of a compressor prior to rotating stall. In this investigation, Digital Particle Imaging Velocimetry (DPIV) is used in conjunction with dynamic pressure transducers to simultaneously capture transient velocity and pressure measurements in the non-stationary flow field during compressor surge. DPIV is an instantaneous, planar measurement technique which is ideally suited for studying transient flow phenomena in high speed turbomachinery and has been used previously to successfully map the stable operating point flow field in the diffuser of a high speed centrifugal compressor. Through the acquisition of both DPIV images and transient pressure data, the time evolution of the unsteady flow during surge is revealed.

  4. Modeling the Origin and Possible Control of the Wealth Inequality Surge

    PubMed Central

    Berman, Yonatan; Shapira, Yoash; Ben-Jacob, Eshel

    2015-01-01

    The rapid increase of wealth inequality in the past few decades is a most disturbing social and economic issue of our time. In order to control, and even reverse that surge, its origin and underlying mechanisms should be revealed. One of the challenges in studying these mechanisms is to incorporate realistic individual dynamics in the population level in a self-consistent manner. Our theoretical approach meets the challenge by using interacting multi-agent master-equations to model the dynamics of wealth inequality. The model is solved using stochastic multi-agent iterated maps. Taking into account growth rate, return on capital, private savings and economic mobility, we were able to capture the historical dynamics of wealth inequality in the United States during the course of the 20th century. We show that the fraction of capital income in the national income and the fraction of private savings are the critical factors that govern the wealth inequality dynamics. In addition, we found that economic mobility plays a crucial role in wealth accumulation. Notably, we found that the major decrease in private savings since the 1980s could be associated primarily with the recent surge in wealth inequality and if nothing changes in this respect we predict further increase in wealth inequality in the future. However, the 2007–08 financial crisis brought an opportunity to restrain the wealth inequality surge by increasing private savings. If this trend continues, it may lead to prevention, and even reversing, of the ongoing inequality surge. PMID:26107388

  5. Observations on Rotating Cavitation and Cavitation Surge From The Development of the Fastrac Engine Turbopump

    NASA Technical Reports Server (NTRS)

    Zoladz, Thomas F.; Turner, James E. (Technical Monitor)

    2000-01-01

    The effects of rotating cavitation and cavitation surges on the Fastrac Engine Turbopump are described in a viewgraph presentation format. The bent inducer blade dilemma and observations of unsteady data and oscillation components are discussed. The pump-feed system stability modeling assessment is outlined. Recommendations are made urging further investigation.

  6. Numerical simulation of MEMS-based blade load distribution control in centrifugal compressor surge suppression

    NASA Astrophysics Data System (ADS)

    Beneda, Károly

    2012-11-01

    The utilization of turbomachines requires up-to-date technologies to ensure safe operation throughout the widest possible range that makes novel ideas necessary to cope with classic problems. One of the most dangerous instability in compression systems is surge that has to be suppressed before its onset to avoid structural damages as well as other adverse consequences in the system. As surge occurs at low delivered mass flow rates the conventional widely spread surge control is based on bypassing the unnecessary airflow back to the atmosphere. This method has been implemented on a large number of aircraft and provides a robust control on suppressing compressor surge while creating a significant efficiency loss. This paper deals with an idea that has been originally designed as a fixed geometry that could be realized using up-to-date MEMS technology resulting in moderate losses but comparable stability enhancement. Previously the author has established the one-dimensional mathematical model of the concept, but it is indispensable - before the real instrument can be developed - to carry out detailed numerical simulation of the device. The aim of the paper is to acquaint the efforts of this CFD simulation.

  7. The Cool Surge Following Flux Emergence in a Radiation-MHD Experiment

    NASA Astrophysics Data System (ADS)

    Nóbrega-Siverio, D.; Moreno-Insertis, F.; Martínez-Sykora, J.

    2016-05-01

    Cool and dense ejections, typically Hα surges, often appear alongside EUV or X-ray coronal jets as a result of the emergence of magnetized plasma from the solar interior. Idealized numerical experiments explain those ejections as being indirectly associated with the magnetic reconnection taking place between the emerging and preexisting systems. However, those experiments miss basic elements that can importantly affect the surge phenomenon. In this paper we study the cool surges using a realistic treatment of the radiation transfer and material plasma properties. To that end, the Bifrost code is used, which has advanced modules for the equation of state of the plasma, photospheric and chromospheric radiation transfer, heat conduction, and optically thin radiative cooling. We carry out a 2.5D experiment of the emergence of magnetized plasma through (meso) granular convection cells and the low atmosphere to the corona. Through detailed Lagrange tracing we study the formation and evolution of the cool ejection and, in particular, the role of the entropy sources; this allows us to discern families of evolutionary patterns for the plasma elements. In the launch phase, many elements suffer accelerations well in excess of gravity; when nearing the apex of their individual trajectories, instead, the plasma elements follow quasi-parabolic trajectories with accelerations close to {g}⊙ . We show how the formation of the cool ejection is mediated by a wedge-like structure composed of two shocks, one of which leads to the detachment of the surge from the original emerged plasma dome.

  8. Surge Block Method for Controlling Well Clogging and Sampling Sediment during Bioremediation

    SciTech Connect

    Wu, Wei-min; Watson, David B; Luo, Jian; Carley, Jack M; Mehlhorn, Tonia L; Kitanidis, Peter K.; Jardine, Philip; Criddle, Craig

    2013-01-01

    A surge block treatment method (i.e. inserting a solid rod plunger with a flat seal that closely fits the casing interior into a well and stocking it up and down) was performed for the rehabilitation of wells clogged with biomass and for the collection of time series sediment samples during in situ bioremediation tests for U(VI) immobilization at a the U.S. Department of Energy site in Oak Ridge, TN. The clogging caused by biomass growth had been controlled by using routine surge block treatment for18 times over a nearly four year test period. The treatment frequency was dependent of the dosage of electron donor injection and microbial community developed in the subsurface. Hydraulic tests showed that the apparent aquifer transmissivity at a clogged well with an inner diameter (ID) of 10.16 cm was increased by 8 13 times after the rehabilitation, indicating the effectiveness of the rehabilitation. Simultaneously with the rehabilitation, the surge block method was successfully used for collecting time series sediment samples composed of fine particles (clay and silt) from wells with ID 1.9 10.16 cm for the analysis of mineralogical and geochemical composition and microbial community during the same period. Our results demonstrated that the surge block method provided a cost-effective approach for both well rehabilitation and frequent solid sampling at the same location.

  9. The effect of density stratification on the prediction of global storm surges

    NASA Astrophysics Data System (ADS)

    Kodaira, Tsubasa; Thompson, Keith R.; Bernier, Natacha B.

    2016-12-01

    With the long-term goal of developing an operational forecast system for total water level, we conduct a hindcast study of global storm surges for Fall 2014 using a baroclinic ocean model based on the NEMO framework. The model has 19 vertical levels, a horizontal resolution of 1/12°, and is forced by hourly forecasts of atmospheric wind and air pressure. Our first objective is to evaluate the model's ability to predict hourly sea levels recorded by a global array of 257 tide gauges. It is shown that the model can provide reasonable predictions of surges for the whole test period at tide gauges with relatively large tidal residuals (i.e., gauges where the standard deviation of observed sea level, after removal of the tide, exceeds 5 cm). Our second objective is to quantify the effect of density stratification on the prediction of global surges. It is found that the inclusion of density stratification increases the overall predictive skill at almost all tide gauges. The increase in skill for the instantaneous peak surge is smaller. The location for which the increase in overall skill is largest (east coast of South Africa) is discussed in detail and physical reasons for the improvement are given.

  10. Modeling the Origin and Possible Control of the Wealth Inequality Surge.

    PubMed

    Berman, Yonatan; Shapira, Yoash; Ben-Jacob, Eshel

    2015-01-01

    The rapid increase of wealth inequality in the past few decades is a most disturbing social and economic issue of our time. In order to control, and even reverse that surge, its origin and underlying mechanisms should be revealed. One of the challenges in studying these mechanisms is to incorporate realistic individual dynamics in the population level in a self-consistent manner. Our theoretical approach meets the challenge by using interacting multi-agent master-equations to model the dynamics of wealth inequality. The model is solved using stochastic multi-agent iterated maps. Taking into account growth rate, return on capital, private savings and economic mobility, we were able to capture the historical dynamics of wealth inequality in the United States during the course of the 20th century. We show that the fraction of capital income in the national income and the fraction of private savings are the critical factors that govern the wealth inequality dynamics. In addition, we found that economic mobility plays a crucial role in wealth accumulation. Notably, we found that the major decrease in private savings since the 1980s could be associated primarily with the recent surge in wealth inequality and if nothing changes in this respect we predict further increase in wealth inequality in the future. However, the 2007-08 financial crisis brought an opportunity to restrain the wealth inequality surge by increasing private savings. If this trend continues, it may lead to prevention, and even reversing, of the ongoing inequality surge.

  11. Storm surge observed by Chinese HY-2A satellite radar altimetry

    NASA Astrophysics Data System (ADS)

    Yang, J.; Li, X.; Han, G.; Chen, N.; Chen, D.

    2017-02-01

    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. For example, a storm surge induced by tropical cyclone Funso in the Southwest Indian Ocean near Mozambique in January 2012 is observed by HY-2A satellite altimetry. The storm surge magnitude is estimated to be 0.49 m and the cross-shelf e-folding decay scale to be 92 km. The present study shows that the HY-2A satellite altimetry is a useful tool for monitoring storm surges and their impacts in the Indian Ocean.

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

    NASA Astrophysics Data System (ADS)

    Xie, Lian; Liu, Huiqing; Peng, Machuan

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

  13. Forecasting of Storm-Surge Floods Using ADCIRC and Optimized DEMs

    NASA Technical Reports Server (NTRS)

    Valenti, Elizabeth; Fitzpatrick, Patrick

    2006-01-01

    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. To keep the computational load manageable, this work was conducted using only the wind stress, calculated by using historical data from Hurricane Camille, as the input condition for the model. Hurricane storm-surge simulations were performed on an

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

  15. Strategic Engagement of Technical Surge Capacity for Intensified Polio Eradication Initiative in Nigeria, 2012–2015

    PubMed Central

    Yehualashet, Yared G.; Mkanda, Pascal; Gasasira, Alex; Erbeto, Tesfaye; Onimisi, Anthony; Horton, Janet; Banda, Richard; Tegegn, Sisay G.; Ahmed, Haruna; Afolabi, Oluwole; Wadda, Alieu; Vaz, Rui G.; Nsubuga, Peter

    2016-01-01

    Background. Following the 65th World Health Assembly (WHA) resolution on intensification of the Global Poliomyelitis Eradication Initiative (GPEI), the Nigerian government, with support from the World Health Organization (WHO) and other partners, implemented a number of innovative strategies to curb the transmission of wild poliovirus (WPV) in the country. One of the innovations successfully implemented since mid 2012 is the WHO's engagement of surge capacity personnel. Methods. The WHO reorganized its functional structure, adopted a transparent recruitment and deployment process, provided focused technical and management training, and applied systematic accountability framework to successfully manage the surge capacity project in close collaboration with the national counterparts and partners. The deployment of the surge capacity personnel was guided by operational and technical requirement analysis. Results. Over 2200 personnel were engaged, of whom 92% were strategically deployed in 11 states classified as high risk on the basis of epidemiological risk analysis and compromised security. These additional personnel were directly engaged in efforts aimed at improving the performance of polio surveillance, vaccination campaigns, increased routine immunization outreach sessions, and strengthening partnership with key stakeholders at the operational level, including community-based organizations. Discussion. Programmatic interventions were sustained in states in which security was compromised and the risk of polio was high, partly owing to the presence of the surge capacity personnel, who are engaged from the local community. Since mid-2012, significant programmatic progress was registered in the areas of polio supplementary immunization activities, acute flaccid paralysis surveillance, and routine immunization with the support of the surge capacity personnel. As of 19 June 2015, the last case of WPV was reported on 24 July 2014. The surge infrastructure has

  16. Europa's opposition surge in the near-infrared: interpreting disk-integrated observations by Cassini VIMS

    NASA Astrophysics Data System (ADS)

    Simonelli, Damon P.; Buratti, Bonnie J.

    2004-11-01

    Near-infrared observations of Europa's disk-integrated opposition surge by Cassini VIMS, first published in Fig. 4 of Brown et al. (2003, Icarus, 164, 461), have now been modeled with the commonly used Hapke photometric function. The VIMS data set emphasizes observations at 16 solar phase angles from 0.4° to 0.6°—the first time the <1° phase "heart" of Europa's opposition surge has been observed this well in the near-IR. This data set 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 μm, 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° phase is similar at all three wavelengths (to within the error bars) and this common slope is similar to the phase coefficient seen in visible-light observations of Europa. The two components of the opposition surge—involving different models of the physical cause of the surge—are the Shadow Hiding Opposition Effect (SHOE) and the Coherent Backscatter Opposition Effect (CBOE). Because of sparse VIMS phase coverage, it is not possible to constrain all the surge parameters at once in a Hapke function that has both SHOE and CBOE; accordingly, we performed separate Hapke fits for SHOE-only and CBOE-only surges. At 2.25 μm, where VIMS data are somewhat noisy, both types of surges can mimic the slope of the VIMS phase curve at <1° phase. At 0.91 and 1.73 μm, however—where VIMS data are "cleaner"—CBOE does a noticeably poorer job than SHOE of matching the VIMS phase coefficient at <1° phase; in particular, the best CBOE fit insists on having a steeper phase-curve slope than the data. This discrepancy suggests that Europa's near-IR opposition surge cannot be explained by CBOE alone and must have a significant SHOE component, even at wavelengths where Europa is bright.

  17. Winter speed-up of ice flow at quiescent surge-type glaciers in Yukon, Canada

    NASA Astrophysics Data System (ADS)

    Furuya, M.; Abe, T.

    2013-12-01

    Glacier surge exhibits order-of-magnitude faster velocity and km-scale terminus advance during its short active phase after a long quiescent period. The observations of glacier surge are still limited, and the mechanisms of glacier surge cycle remain elusive. Moreover, with the exception of several well-examined glaciers, the glacier dynamics during their quiescent periods remains even more uncertain due to the paucity of surface velocity measurement data. Here we examined spatial-temporal changes in the ice surface velocity of surge-type glaciers in the St. Elias Mountains near the border of Alaska and Yukon during the period from December 2006 to March 2011. We applied the offset-tracking (feature-tracking) technique to the L-band synthetic aperture radar (SAR) images derived from the Japanese Advanced Land Observation Satellite (ALOS). The Chitina, Anderson, Walsh, and Logan Glaciers, the major subpolar surge-type glaciers of the Chitina River valley system, could be examined with the highest temporal resolution because of the overlap of multiple satellite tracks. We have found significant upstream accelerations from fall to winter at a number of glaciers during their quiescence. Moreover, whereas the upstream propagating summer speed-up was observed, the winter speed-up propagated from upstream to downglacier. Although the winter speed-up seems to be at odds with the well-known summer speed-up, these observations are consistent with the fragmentary but well-known fact of glacier surge that often initiates in winter, suggesting that some of the mechanisms would be valid even during quiescent phases. Ice surface velocity at mountain glaciers and ice sheets typically exhibits the greatest acceleration from spring to early summer, followed by deceleration in mid-summer to fall, and is slowest in winter. These short-term velocity changes are attributed to subglacial slip associated with water pressure changes that occur because of the seasonal variability of

  18. Linking storm surge activity and circulation variability along the Spanish coast through a synoptic pattern classification

    NASA Astrophysics Data System (ADS)

    Rasilla Álvarez, Domingo; Garcia Codrón, Juan Carlos

    2010-05-01

    The potentially negative consequences resulting from the estimations of global sea level rising along the current century are a matter of serious concern in many coastal areas worldwide. Most of the negative consequences of the sea level variability, such as flooding or erosion, are linked to episodic events of strong atmospheric forcing represented by deep atmospheric disturbances, especially if they combine with extreme astronomical high tides. Moreover, the interaction between the prevailing flows during such events and the actual orientation of the coast line might accelerate or mitigate such impacts. This contribution analyses sea surge variations measured at five tide-gauge stations located around the Iberian Peninsula and their relationships with regional scale circulation patterns with local-scale winds. Its aim is to improve the knowledge of surge related-coastal-risks by analysing the relationship between surges and their atmospheric forcing factors at different spatial scales. The oceanographic data set consists of hourly data from 5 tide gauge stations (Santander, Vigo, Bonanza, Málaga, Valencia and Barcelona) disseminated along the Spanish coastline, provided by Puertos del Estado. To explore the atmospheric mechanisms responsible for the sign and magnitude of sea surges, a regional Eulerian approach (a synoptic typing) were combined with a larger-scale Lagrangian method, based on the analysis of storm-tracks over the Atlantic and local information (synop reports) obtained from the closest meteorological stations to the tide gauges. The synoptic catalogue was obtained following a procedure that combines Principal Component Analysis (PCA) for reduction purposes and clustering (Ward plus K-means) to define the circulation types. Sea level pressure, surface 10m U and V wind components gridded data were obtained from NCEP Reanalysis, while storm tracks and cyclone statistics were extracted from the CDC Map Room Climate Products Storm Track Data (http

  19. Evolution of surge levels inside of the Seine Bay : application to Johanna and Xynthia storms

    NASA Astrophysics Data System (ADS)

    Laborie, Vanessya; Sergent, Philippe; Hissel, François

    2014-05-01

    Within the Technical Commission for the Study and the Evaluation of Maritime Submersions in the Seine Estuary (CteeSMES), whose aim is to improve the collective knowledge on physical processes related to maritime surge levels, a numerical model of the Seine Estuary based on TELEMAC2D has been constructed to study the evolution of surge levels from the ocean to the harbour area of Le Havre and, in particular, evaluate the amplification of the global signal and the apparition of seiches inside René Coty's basin. The bathymetry of the model were partially provided by Le Havre and Rouen Harbours for the north-east part of the model. The numerical model was calibrated on JOHANNA and XYNTHIA storm events, which respectively occurred in March 2008 and in February 2010. Tide propagation was firstly calibrated through the test of several tide models used at the maritime boundary and a change of the friction coefficient on the bottom. Concerning the tide calibration, numerical results were compared with the predicted tide provided at Le Havre by two softwares : PREDIT and REFMAR (SHOM). To calibrate the global signal (tide + surge levels), measurements available on ten outputs of the Seine Estuary and provided by ports of Le Havre and Rouen were used to optimize the coefficient for wind influence. Winds and pressure fields were CFSR data. Once the numerical model of the Seine Bay 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 inside René Coty's basin. Consistently with measurements, numerical results show the apparition of an oscillating signal which adds to the signal at the entry of the Harbour. At the moment, the amplification is under-estimated, and results have to be improved to represent properly the process of the seiche inside the port, near the François Ier lock.

  20. Towards improved storm surge models in the northern Bay of Bengal

    NASA Astrophysics Data System (ADS)

    Krien, Y.; Testut, L.; Islam, A. K. M. S.; Bertin, X.; Durand, F.; Mayet, C.; Tazkia, A. R.; Becker, M.; Calmant, S.; Papa, F.; Ballu, V.; Shum, C. K.; Khan, Z. H.

    2017-03-01

    The northern Bay of Bengal is home to some of the deadliest cyclones recorded during the last decades. Storm surge models developed for this region significantly improved in recent years, but they still fail to predict patterns of coastal flooding with sufficient accuracy. In the present paper, we make use of a state-of-the art numerical modeling system with improved bathymetric and topographic data to identify the strengths, weaknesses, and to suggest areas for improvement of current storm surge models in this area. The new model is found to perform relatively well in reproducing waves characteristics and maximum water levels for the two extreme cyclones studied here: Phailin (2013) and Sidr (2007). The wave setup turns out to be small compared to the wind-driven surge, although it still plays a significant role for inland flooding. Relatively large tide-surge interactions mainly due to shallow water effects are also evidenced by the model. These findings plead in favor of further efforts to improve the representation of the bathymetry, especially in the nearshore area, and the implementation of models including tides and radiation stresses explicitly. The main limit of the model is its inability to predict the detailed patterns of coastal flooding satisfactorily. The reason lies mainly in the fact that topographic data also need to be further improved. In particular, a good knowledge of embankments characteristics (crest elevation and their condition) is found to be of primary importance to represent inland flooding correctly. Public authorities should take urgent action to ensure that better data are available to the scientific community, so that state-of-the-art storm surge models reaching a sufficiently high level of confidence can be used for emergency preparedness and to implement mitigation strategies in the northern Bay of Bengal.

  1. Storm surges in the Mediterranean Sea: Variability and trends under future climatic conditions

    NASA Astrophysics Data System (ADS)

    Androulidakis, Yannis S.; Kombiadou, Katerina D.; Makris, Christos V.; Baltikas, Vassilis N.; Krestenitis, Yannis N.

    2015-09-01

    The trends of storm surge extremes in the Mediterranean Sea for a period of 150 years (1951-2100) are explored, using a high-resolution storm surge model. Numerical simulations are forced by the output of regional climate simulations with RegCM3, which uses IPCC's historical data on greenhouse gasses emissions for the (past) period 1951-2000, and IPCC's A1B climate scenario for the (future) period 2001-2100. Comparisons between observations and modeling results show good agreement and confirm the ability of our model to estimate the response of the sea surface to future climatic conditions. We investigate the future trends, the variability and frequency of local extremes and the main forcing mechanisms that can induce strong surges in the Mediterranean region. Our results support that there is a general decreasing trend in storminess under the considered climate scenario, mostly related to the frequency of local peaks and the duration and spatial coverage of the storm surges. The northward shift in the location of storm tracks is a possible reason for this storminess attenuation, especially over areas where the main driving factor of extreme events is the inverted barometer effect. However, the magnitudes of sea surface elevation extremes may increase in several Mediterranean sub-regions, i.e., Southern Adriatic, Balearic and Tyrrhenian Seas, during the 21st century. There are clear distinctions in the contributions of winds and pressure fields to the sea level height for various regions of the Mediterranean Sea, as well as on the seasonal variability of extreme values; the Aegean and Adriatic Seas are characteristic examples, where high surges are predicted to be mainly induced by low pressure systems and favorable winds, respectively.

  2. Revealing glacier flow and surge dynamics from animated satellite image sequences: examples from the Karakoram

    NASA Astrophysics Data System (ADS)

    Paul, F.

    2015-11-01

    Although animated images are very popular on the internet, they have so far found only limited use for glaciological applications. With long time series of satellite images becoming increasingly available and glaciers being well recognized for their rapid changes and variable flow dynamics, animated sequences of multiple satellite images reveal glacier dynamics in a time-lapse mode, making the otherwise slow changes of glacier movement visible and understandable to the wider public. For this study, animated image sequences were created for four regions in the central Karakoram mountain range over a 25-year time period (1990-2015) from freely available image quick-looks of orthorectified Landsat scenes. The animations play automatically in a web browser and reveal highly complex patterns of glacier flow and surge dynamics that are difficult to obtain by other methods. In contrast to other regions, surging glaciers in the Karakoram are often small (10 km2 or less), steep, debris-free, and advance for several years to decades at relatively low annual rates (about 100 m a-1). These characteristics overlap with those of non-surge-type glaciers, making a clear identification difficult. However, as in other regions, the surging glaciers in the central Karakoram also show sudden increases of flow velocity and mass waves travelling down glacier. The surges of individual glaciers are generally out of phase, indicating a limited climatic control on their dynamics. On the other hand, nearly all other glaciers in the region are either stable or slightly advancing, indicating balanced or even positive mass budgets over the past few decades.

  3. Hindcast and validation of Hurricane Ike (2008) waves, forerunner, and storm surge

    NASA Astrophysics Data System (ADS)

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

    2013-09-01

    Hurricane Ike (2008) made landfall near Galveston, Texas, as a moderate intensity storm. Its large wind field in conjunction with the Louisiana-Texas coastline's broad shelf and large scale concave geometry generated waves and surge that impacted over 1000 km of coastline. Ike's complex and varied wave and surge response physics included: the capture of surge by the protruding Mississippi River Delta; the strong influence of wave radiation stress gradients on the Delta adjacent to the shelf break; the development of strong wind driven shore-parallel currents and the associated geostrophic setup; the forced early rise of water in coastal bays and lakes facilitating inland surge penetration; the propagation of a free wave along the southern Texas shelf; shore-normal peak wind-driven surge; and resonant and reflected long waves across a wide continental shelf. Preexisting and rapidly deployed instrumentation provided the most comprehensive hurricane response data of any previous hurricane. More than 94 wave parameter time histories, 523 water level time histories, and 206 high water marks were collected throughout the Gulf in deep water, along the nearshore, and up to 65 km inland. Ike's highly varied physics were simulated using SWAN + ADCIRC, a tightly coupled wave and circulation model, on SL18TX33, a new unstructured mesh of the Gulf of Mexico, Caribbean Sea, and western Atlantic Ocean with high resolution of the Gulf's coastal floodplain from Alabama to the Texas-Mexico border. A comprehensive validation was made of the model's ability to capture the varied physics in the system.

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

    USGS Publications Warehouse

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

    2010-01-01

    Isolated wetlands in the Southeastern United States are dynamic habitats subject to fluctuating environmental conditions. Wetlands located near marine environments are subject to alterations in water chemistry due to storm surge during hurricanes. The objective of our study was to evaluate the effect of storm surge overwash on wetland amphibian communities. Thirty-two wetlands in northwestern Florida were sampled over a 45-month period to assess amphibian species richness and water chemistry. During this study, seven wetlands were overwashed by storm surge from Hurricane Dennis which made landfall 10 July 2005 in the Florida panhandle. This event allowed us to evaluate the effect of storm surge overwash on water chemistry and amphibian communities of the wetlands. Specific conductance across all wetlands was low pre-storm (<100 ??S/cm), but increased post-storm at the overwashed wetlands (x?? = 7,613 ??S/cm). Increased specific conductance was strongly correlated with increases in chloride concentrations. Amphibian species richness showed no correlation with specific conductance. One month post-storm we observed slightly fewer species in overwashed compared with non-overwashed wetlands, but this trend did not continue in 2006. More species were detected across all wetlands pre-storm, but there was no difference between overwashed and non-overwashed wetlands when considering all amphibian species or adult anurans and larval anurans separately. Amphibian species richness did not appear to be correlated with pH or presence of fish although the amphibian community composition differed between wetlands with and without fish. Our results suggest that amphibian communities in wetlands in the southeastern United States adjacent to marine habitats are resistant to the effects of storm surge overwash. ?? 2010 Springer Science+Business Media B.V.

  5. Surge Capacity and Capability. A Review of the History and Where the Science is Today Regarding Surge Capacity during a Mass Casualty Disaster

    PubMed Central

    Kearns, Randy D.; Cairns, Bruce A.; Cairns, Charles B.

    2014-01-01

    Disasters which include countless killed and many more injured, have occurred throughout recorded history. Many of the same reports of disaster also include numerous accounts of individuals attempting to rescue those in great peril and render aid to the injured and infirmed. The purpose of this paper is to briefly discuss the transition through several periods of time with managing a surge of many patients. This review will focus on the triggering event, injury and illness, location where the care is provided and specifically discuss where the science is today. PMID:24795873

  6. What is the impact of Harmattan surges on desert dust emission in North Africa?

    NASA Astrophysics Data System (ADS)

    Fiedler, Stephanie; Kaplan, Michael L.; Knippertz, Peter

    2015-04-01

    Desert dust aerosols have important implications in the Earth system, but their emission amount has a large model uncertainty. Improving the most important meteorological processes for dust-emitting winds helps to reduce this uncertainty. However, the dominant meteorological mechanisms for the large dust emission during spring remain unclear. This time of year is characterized by mobile, long-lived cyclones and Harmattan surges which are capable to uplift dust aerosol for long-range atmospheric transport. Emission near to the centre of mobile, long-lived cyclones are associated with a small mass of dust emission over the northern Sahara in spring, despite their most frequent occurrence in this season. Harmattan surges are proposed to be more efficient in emitting dust aerosol in spring. These events manifest themselves as a postfrontal strengthening of near-surface winds with a continental impact on dust emission. The present study shows the first long-term climatology of dust emission associated with Harmattan surges over North Africa. Using a newly-developed automated identification, Harmattan surges are statistically analysed in 32 years of ERA-Interim re-analysis from the European Centre for Medium-Range Weather Forecasts. The results show 34 events per year in the annual mean. Spring is herein the most active season with the largest mean number and duration of Harmattan surges, in contrast to summer with virtually no activity. The offline dust emission model by Tegen et al (2002) is used to calculate emissions with ERA-Interim data. Combining these results with the Harmattan surges allows a first quantitative estimate of the associated emission mass. The results highlight that a fraction of 32 % of the total emission is associated with these events, annually and spatially averaged across North Africa. This amount exceeds the annual mean contribution of nocturnal low-level jets to dust emission, which is known as one of the most important drivers for North

  7. 3D strain measurement in soft tissue: demonstration of a novel inverse finite element model algorithm on MicroCT images of a tissue phantom exposed to negative pressure wound therapy.

    PubMed

    Wilkes, R; Zhao, Y; Cunningham, K; Kieswetter, K; Haridas, B

    2009-07-01

    This study describes a novel system for acquiring the 3D strain field in soft tissue at sub-millimeter spatial resolution during negative pressure wound therapy (NPWT). Recent research in advanced wound treatment modalities theorizes that microdeformations induced by the application of sub-atmospheric (negative) pressure through V.A.C. GranuFoam Dressing, a reticulated open-cell polyurethane foam (ROCF), is instrumental in regulating the mechanobiology of granulation tissue formation [Saxena, V., Hwang, C.W., Huang, S., Eichbaum, Q., Ingber, D., Orgill, D.P., 2004. Vacuum-assisted closure: Microdeformations of wounds and cell proliferation. Plast. Reconstr. Surg. 114, 1086-1096]. While the clinical response is unequivocal, measurement of deformations at the wound-dressing interface has not been possible due to the inaccessibility of the wound tissue beneath the sealed dressing. Here we describe the development of a bench-test wound model for microcomputed tomography (microCT) imaging of deformation induced by NPWT and an algorithm set for quantifying the 3D strain field at sub-millimeter resolution. Microdeformations induced in the tissue phantom revealed average tensile strains of 18%-23% at sub-atmospheric pressures of -50 to -200 mmHg (-6.7 to -26.7 kPa). The compressive strains (22%-24%) and shear strains (20%-23%) correlate with 2D FEM studies of microdeformational wound therapy in the reference cited above. We anticipate that strain signals quantified using this system can then be used in future research aimed at correlating the effects of mechanical loading on the phenotypic expression of dermal fibroblasts in acute and chronic ulcer models. Furthermore, the method developed here can be applied to continuum deformation analysis in other contexts, such as 3D cell culture via confocal microscopy, full scale CT and MRI imaging, and in machine vision.

  8. An example of the association of X-ray and UV emission with H-alpha surges

    NASA Technical Reports Server (NTRS)

    Schmieder, B.; Mein, P.; Simnett, G. M.; Tandberg-Hanssen, E.

    1988-01-01

    From H-alpha UV, and X-ray data, the nature of a well-observed surge on November 12, 1980 has been studied to try to understand the relationships between the mechanical motions and the high-temperature emissions. The cool (H-alpha) and the hot (O v) parts of the surge plasma both show velocities in the range of 100-120 km/s. The kinetic and potential energies of the surge are two orders of magnitude higher than the radiative energy. The observations suggest that the surge occurs in open structures parallel to one leg of a large scale coronal magnetic loop. The energy is released principally in the open structure (surge) and only a small amount heats the coronal loop (X-ray signature). This energy division should probably not be treated as a general characteristic of surge events. Different events are expected to exhibit a different energy balance, and this can account for the lack of a consensus in the previous literature regarding surge/X-ray associations.

  9. Modeling the Effectiveness of a Storm Surge Barrier System for the Houston Ship Channel during Hurricane Events

    NASA Astrophysics Data System (ADS)

    Torres, J.; Fang, N.; Bedient, P. B.; Christian, J.

    2013-12-01

    The Houston Ship Channel (HSC) is home to the second-busiest port in the nation in terms of overall tonnage, and contains one of the largest petrochemical complexes in the world. As such, undisturbed operations of the HSC are vital to ensuring the economic prosperity of local, state, and national interests. History has proven that coastal infrastructure systems and operations at the HSC are easily disrupted by rainfall and storm surge from intense hurricanes (e.g. Hurricane Ike). To quantitatively evaluate flood and storm surge vulnerability, a coupled riverine-coastal hydraulic model is developed for the HSC and Galveston Bay as an initial testbed for simulating extreme flooding scenarios. A numerical investigation is made on the coupled interactions of upstream watershed runoff and downstream surge level occurrences, as well as the effectiveness of a proposed storm surge gate protecting inland HSC infrastructure during a simulated Hurricane Ike event, and associated Ike variations. Sensitivities in peak stage, instantaneous flow, and relative timing of these events are explored for Hurricane Ike rainfall-surge conditions and various perturbations related thereto. Results show that a surge gate system can be effective to reduce flood elevation and floodplain extent in the HSC area, but that net flood protection is largely dependent on the varied timings on the watershed rainfall-runoff and coastal surge dynamics.

  10. The landscape architecture of the forefield of Eyjabakkajökull, a surge-type glacier in Iceland

    NASA Astrophysics Data System (ADS)

    Schomacker, A.; Benediktsson

    2012-12-01

    A new geomorphological map of the forefield of the Eyjabakkajökull surge-type glacier in Iceland is presented. The map is based on field mapping and aerial photography from 2008 that covers c. 58 km2, including the Eyjabakkajökull glacier tongue and its entire forefield. When viewed in the context of glacial landsystems, the map identifies landforms that can be regarded as characteristic of glacier surging; in particular, crevasse-fill ridges, concertina eskers, long flutings, hummocky and ice-cored moraines, pitted outwash plains, and glaciotectonic end moraines. In addition, landforms that are common for many glacial environments but less typical of surging, were also identified and mapped; specifically, kames, sinuous eskers, sandar, braided channels, and outwash fans. Eyjabakkajökull has experienced surges every 21-40 years during the past 2200 years; hence, the large-scale landscape architecture is likely a result of dozens of surges. However, the glacial sediments and landforms presently identified in the forefield result from the most recent and historically known surges of Eyjabakkajökull in 1890, 1931, 1938 and 1972. The association of sediments and landforms in the Eyjabakkajökull forefield is diagnostic of glacier surging and may serve as a modern analogue in palaeoglaciological reconstructions.

  11. Thermodynamic and dynamic structure of atmosphere over the east coast of Peninsular Malaysia during the passage of a cold surge

    NASA Astrophysics Data System (ADS)

    Samah, Azizan Abu; Babu, C. A.; Varikoden, Hamza; Jayakrishnan, P. R.; Hai, Ooi See

    2016-08-01

    An intense field observation was carried out for a better understanding of cold surge features over Peninsular Malaysia during the winter monsoon season. The study utilizes vertical profiles of temperature, humidity and wind at high vertical and temporal resolution over Kota Bharu, situated in the east coast of Peninsular Malaysia. LCL were elevated during the passage of the cold surge as the relative humidity values decreased during the passage of cold surge. Level of Free Convection were below 800 hPa and equilibrium levels were close to the LFC in most of the cases. Convective available potential energy and convection inhibition energy values were small during most of the observations. Absence of local heating and instability mechanism are responsible for the peculiar thermodynamic structure during the passage of the cold surge. The wind in the lower atmosphere became northeasterly and was strong during the entire cold surge period. A slight increase in temperature near the surface and a drop in temperature just above the surface were marked by the passage of the cold surge. A remarkable increase in specific humidity was observed between 970 and 900 hPa during the cold surge period. Further, synoptic scale features were analyzed to identify the mechanism responsible for heavy rainfall. Low level convergence, upper level divergence and cyclonic vorticity prevailed over the region during the heavy rainfall event. Dynamic structure of the atmosphere as part of the organized convection associated with the winter monsoon was responsible for the vertical lifting and subsequent rainfall.

  12. InSAR observations and models of crustal deformation due to a glacial surge in Iceland

    NASA Astrophysics Data System (ADS)

    Auriac, A.; Sigmundsson, F.; Hooper, A.; Spaans, K. H.; Björnsson, H.; Pálsson, F.; Pinel, V.; Feigl, K. L.

    2014-09-01

    Surges are common at all the major ice caps in Iceland. Ice masses of gigatons may shift from the upper part of the outlet glacier towards the terminus in a few months, advancing the glacier front by up to several kilometres. The advancing ice front may be up to 100 m thick, increasing the load on crustal rocks correspondingly. We use the observed change in crustal loading during a surge of the western part of the Vatnajökull ice cap, Iceland, during 1993-1995 and the corresponding elastic crustal deformation, surveyed with interferometric synthetic aperture radar, to investigate the material properties of the solid Earth in this region. Crustal subsidence due to the surge reaches ˜75 mm at the edge of the Síðujökull outlet glacier. This signal is mixed with a broad uplift signal of ˜12 mm yr-1, relative to our reference area, caused by the ongoing retreat of Vatnajökull in response to climate change. We disentangle the two signals by linear inversion. Finite element modelling is used to investigate the elastic Earth response of the surge, as well as to confirm that no significant viscoelastic deformation occurred as a consequence of the surge. The modelling leads to estimates of the Young's modulus and Poisson's ratio of the underlying Earth. Comparison between the observed and modelled deformation fields is made using a Bayesian approach that yields the estimate of a probability distribution for each of the free parameters. Residuals indicate a good agreement between models and observations. One-layer elastic models result in a Young's modulus of 43.2-49.7 GPa (95 per cent confidence) and Poisson's ratio of 0-0.27, after removal of outliers. Our preferred model, with two elastic layers, provides a better fit to the whole surge signal. This model consists of a 1-km-thick upper layer with an average Young's modulus of 12.9-15.3 GPa and Poisson's ratio of 0.17, overlying a layer with an average Young's modulus of 67.3-81.9 GPa and Poisson's ratio of 0.25.

  13. Active control of surge in centrifugal compressors using magnetic thrust bearing actuation

    NASA Astrophysics Data System (ADS)

    Sanadgol, Dorsa

    This research presents a new method for active surge control in centrifugal compressors with unshrouded impellers using a magnetic thrust bearing to modulate the impeller tip clearance. Magnetic bearings offer the potential for active control of flow instabilities. This capability is highly dependent on the sensitivity of the compressor characteristics to blade tip clearance. If the position of the shaft can be actuated with sufficient authority and speed, the induced pressure modulation makes control of surge promising. The active nature of the magnetic bearing system makes the real-time static and dynamic positioning of the rotor and therefore modulation of the impeller tip clearance possible. A theoretical model is first established that describes the sensitivity of the centrifugal compressor characteristic curve to tip clearance variations induced by axial motion of the rotor. Results from simulation of the nonlinear model for a single stage high-speed centrifugal compressor show that using the proposed control method, mass flow and pressure oscillations associated with compressor surge are quickly suppressed with acceptable tip clearance excursions, typically less than 20% of the available clearance. It is shown that it is possible to produce adequate axial excursions in the clearance between the impeller blades and the adjacent stationary shroud using a magnetic thrust bearing with practical levels of drive voltage. This surge control method would allow centrifugal compressors to reliably and safely operate with a wider range than is currently done in the field. The principal advantage of the proposed approach over conventional surge control methods lies in that, in machines already equipped with magnetic bearing, the method can potentially be implemented by simply modifying controller software. This dispenses with the need to introduce additional hardware, permitting adaptation of existing machinery at virtually no cost. In addition, since the controller is

  14. Variation of Strom Surge Propagation in a Shallow Estuary with Sea Level Rise

    NASA Astrophysics Data System (ADS)

    Herrington, T. O., Jr.; Blumberg, A. F.

    2014-12-01

    Hurricane Sandy made landfall along the New Jersey coast at 8pm EDT on October 29th, 2012. At landfall wind gusts of between 129 and 145 km/hr were recorded in New York and New Jersey. The large wind field associated with the storm generated an extreme storm surge north of the eye at landfall resulting in high-velocity overland storm surge along the northern barrier Islands of the Barnegat Bay followed 7 hours later by a rapid rise in water level along the bayside of the barrier islands. A high-resolution, hydrodynamic model for the Barnegat Bay estuary; including its vast intertidal areas, has been developed and validated to simulate the observed Sandy storm surge. The Barnegat Bay Inundation Model (BBIMS) has a constant 100m resolution and is nested within the three dimensional Stevens NYHOPS ocean circulation model at its offshore open boundary. Wetting and drying of land features in the model's external time step is as low as 0.1 sec in its 2D barotropic mode. This mode provides for the dynamic prediction of depth integrated flood elevations and velocities across land features during inundation events. The BBIMS was calibrated using the NYHOPS hindcast of Hurricane Sandy. The hindcast utilized Sandy over ocean wind field and atmospheric pressure data, offshore wave and tidal boundary forcing, atmospheric heat fluxes, interior stream flow data and was validated against observed water levels and measured high water marks. A comparison against 6 water level time series measured by USGS tide gauges located in the Barnegat Bay verified that the model is able to capture the spatial and temporal variation of water levels in the Bay observed during Hurricane Sandy. A comparison against the verified high water marks found that the model is capable of hincasting overland water elevation to within 0.63ft (one standard deviation) at 71% of the total water marks measured. The modeling results show that strong northerly winds along the axis of the estuary prior to landfall

  15. Remote-sensing-based analysis of the 1996 surge of Northern Inylchek Glacier, central Tien Shan, Kyrgyzstan

    NASA Astrophysics Data System (ADS)

    Häusler, Hermann; Ng, Felix; Kopecny, Alexander; Leber, Diethard

    2016-11-01

    The evolution of Northern Inylchek Glacier and its proglacial lake - Upper Lake Merzbacher - during its 1996 surge and the surrounding decades is analyzed with remote sensing imagery. Overall retreat of the glacier from 1943 to 1996 enlarged the lake to 4 km long and ≈ 100 m deep. The surge in 1996 initiated between 12 September and 7 October and advanced the glacier by 3.7 km to override most of Upper Lake Merzbacher. The surge phase probably ended in December 1996 and involved mean flow velocities across the lower trunk of the glacier that reached 50 m d- 1 over a 32-day period. Water displaced by the surge from Upper Lake Merzbacher, totalling 1.5 × 108 m3 in volume, accelerated filling of Lower Lake Merzbacher downvalley and helped trigger this marginal ice-dammed lake to outburst in a jökulhlaup around late November/early December. The characteristics and duration of the surge render it as similar to temperate glacier surges elsewhere. It may have been facilitated by low basal friction caused by water-saturated sediments in the upper lake bed. Furthermore, bathymetric measurements show that the surge evacuated much sediment into the upper lake, causing its depth to reduce from 20 to 30 m in 1996 to 8 m by 2005 and 2 m by 2011; the corresponding deposition rates imply glacier-catchment specific mean sediment yields of 1.4 to 3.4 × 103 Mg km- 2 a- 1 in the years after the surge. Our study documents novel interactions within a cascade system of glaciers and lakes that exhibits surging and outburst-flood behavior.

  16. Hydraulic modeling of unsteady debris-flow surges with solid-fluid interactions

    USGS Publications Warehouse

    Iverson, Richard M.

    1997-01-01

    Interactions of solid and fluid constituents produce the unique style of motion that typifies debris flows. To simulate this motion, a new hydraulic model represents debris flows as deforming masses of granular solids variably liquefied by viscous pore fluid. The momentum equation of the model describes how internal and boundary forces change as coarse-grained surge heads dominated by grain-contact friction grade into muddy debris-flow bodies more strongly influenced by fluid viscosity and pressure. Scaling analysis reveals that pore-pressure variations can cause flow resistance in surge heads to surpass that in debris-flow bodies by orders of magnitude. Numerical solutions of the coupled momentum and continuity equations provide good predictions of unsteady, nonuniform motion of experimental debris flows from initiation through deposition.

  17. AN ULTRASONIC PHASED ARRAY EVALUATION OF CAST AUSTENITIC STAINLESS STEEL PRESSURIZER SURGE LINE PIPING WELDS

    SciTech Connect

    Diaz, Aaron A.; Cinson, Anthony D.; Crawford, Susan L.; Moran, Traci L.; Anderson, Michael T.

    2010-07-22

    A set of circumferentially oriented thermal fatigue cracks (TFCs) were implanted into three cast austenitic stainless steel (CASS) pressurizer (PZR) surge-line specimens (pipe-to-elbow welds) that were fabricated using vintage CASS materials formed in the 1970s, and flaw responses from these cracks were used to evaluate detection and sizing performance of the phased-array (PA) ultrasonic testing (UT) methods applied. Four different custom-made PA probes were employed in this study, operating nominally at 800 kHz, 1.0 MHz, 1.5 MHz, and 2.0 MHz center frequencies. The CASS PZR surge-line specimens were polished and chemically etched to bring out the microstructures of both pipe and elbow segments. Additional studies were conducted and documented to address baseline CASS material noise and observe possible ultrasonic beam redirection phenomena.

  18. Some observations of currents in shallow water during a storm surge

    NASA Astrophysics Data System (ADS)

    Heathershaw, A. D.

    1982-06-01

    Observations of currents in a shallow coastal embayment, Swansea Bay in the Bristol Channel, U.K., have indicated that during a storm surge residual flows may be five times higher than during quiescent flow periods. In particular near-bed residuals of the order of 10 cm s -1 were observed during the storm surge of 11 November 1977. While the effect of waves on these measurements cannot be eliminated entirely, correlation analyses and comparisons of wave and current records suggest that the effect is likely, in this case, to have been minimal. The observed flow regime suggests that while the residual circulation in Swansea Bay may be influenced by strong SW. winds blowing onshore, offshore winds from a NW. direction have a more significant effect, possibly as a result of wind induced set down in the Bay head. Calculations show that the observed bottom currents can be predicted by a simple constant eddy viscosity model in which tidal mixing is dominant.

  19. A new method of overbalanced perforating and surging of resin for sand control

    SciTech Connect

    Dees, J.M.; Handren, P.J. )

    1994-05-01

    Gravel packing of perforations is the conventional method for sand control in the petroleum industry. Case histories of 12 well treatments provide details of a new procedure for high-energy resin placement that controls sand in a formation. The new consolidation method uses an extremely over-balanced pressure surge with liquid resin on perforations. This paper presents the problem, theory, process description, job procedure, and results of resin treatments with perforating or surging with a high-energy overbalanced pressure pulse. Highlights include potential applications. Benefits of the technique include accelerating on-line production and reducing completion rig time spent on controlling sand. The method appears to yield equal or better results than previous conventional gravel-packing techniques.

  20. Hydraulic Transients in the Long Diversion-Type Hydropower Station with a Complex Differential Surge Tank

    PubMed Central

    Yu, Xiaodong; Zhang, Jian

    2014-01-01

    Based on the theory of hydraulic transients and the method of characteristics (MOC), a mathematic model of the differential surge tank with pressure-reduction orifices (PROs) and overflow weirs for transient calculation is proposed. The numerical model of hydraulic transients is established using the data of a practical hydropower station; and the probable transients are simulated. The results show that successive load rejection is critical for calculating the maximum pressure in spiral case and the maximum rotating speed of runner when the bifurcated pipe is converging under the surge tank in a diversion-type hydropower station; the pressure difference between two sides of breast wall is large during transient conditions, and it would be more serious when simultaneous load rejections happen after load acceptance; the reasonable arrangement of PROs on breast wall can effectively decrease the pressure difference. PMID:25133213

  1. Hydraulic transients in the long diversion-type hydropower station with a complex differential surge tank.

    PubMed

    Yu, Xiaodong; Zhang, Jian; Zhou, Ling

    2014-01-01

    Based on the theory of hydraulic transients and the method of characteristics (MOC), a mathematic model of the differential surge tank with pressure-reduction orifices (PROs) and overflow weirs for transient calculation is proposed. The numerical model of hydraulic transients is established using the data of a practical hydropower station; and the probable transients are simulated. The results show that successive load rejection is critical for calculating the maximum pressure in spiral case and the maximum rotating speed of runner when the bifurcated pipe is converging under the surge tank in a diversion-type hydropower station; the pressure difference between two sides of breast wall is large during transient conditions, and it would be more serious when simultaneous load rejections happen after load acceptance; the reasonable arrangement of PROs on breast wall can effectively decrease the pressure difference.

  2. Mobility of pyroclastic flows and surges at the Soufriere Hills Volcano, Montserrat

    USGS Publications Warehouse

    Calder, E.S.; Cole, P.D.; Dade, W.B.; Druitt, T.H.; Hoblitt, R.P.; Huppert, H.E.; Ritchie, L.; Sparks, R.S.J.; Young, S.R.

    1999-01-01

    The Soufriere Hills Volcano on Montserrat has produced avalanche-like pyroclastic flows formed by collapse of the unstable lava dome or explosive activity. Pyroclastic flows associated with dome collapse generate overlying dilute surges which detach from and travel beyond their parent flows. The largest surges partially transform by rapid sedimentation into dense secondary pyroclastic flows that pose significant hazards to distal areas. Different kinds of pyroclastic density currents display contrasting mobilities indicated by ratios of total height of fall H, run-out distance L, area inundated A and volume transported V. Dome-collapse flow mobilities (characterised by either L/H or A/V 2/3) resemble those of terrestrial and extraterrestrial cold-rockfalls (Dade and Huppert, 1998). In contrast, fountain-fed pumice flows and fine-grained, secondary pyroclastic flows travel slower but, for comparable initial volumes and heights, can inundate greater areas.

  3. Monitoring Inland Storm Surge and Flooding From Hurricane Gustav in Louisiana, September 2008

    USGS Publications Warehouse

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

    2008-01-01

    On August 29-31, 2008, the U.S. Geological Survey (USGS) deployed a mobile monitoring network consisting of 124 pressure transducers (sensors) (figs. 1, 2) at 80 sites over an area of about 4,200 square miles to record the timing, extent, and magnitude of inland hurricane storm surge and coastal flooding generated by Hurricane Gustav, which made landfall in southeastern Louisiana on September 1. One-hundred twenty-one sensors from 61 sites (fig. 3) were recovered. Thirty-seven sites from which sensors were recovered were in the New Orleans area, and the remaining 24 sites were distributed throughout southeastern Louisiana. Sites were categorized as surge (21), riverine flooding (18), anthropogenic (affected by the operation of gates or pumps) (17), or mixed/uncertain on the basis of field observations and the appearance of the water-level data (5).

  4. Measurements of coastal storm surge by the U.S. Geological Survey

    USGS Publications Warehouse

    DelCharco, Michael J.

    1998-01-01

    In the wake of a storm, local, state, and federal emergency planners needed storm surge elevation data as quickly as possible. These data are used by officials to decide what areas are in the greatest need of assistance and what areas qualify for special designations. To accelerate the pace at which storm surge data can be gathered and released, the US geological survey (USGC) has established a network of coastal water elevation gages that are linked to satellite networks. These data are made available in real-time on the World Wide Web. While Internet access is usually fast and reliable, this process can be augmented by cellular phone, two-way radio, and other data communication techniques.

  5. Optimal Control of a Surge-Mode WEC in Random Waves

    SciTech Connect

    Chertok, Allan; Ceberio, Olivier; Staby, Bill; Previsic, Mirko; Scruggs, Jeffrey; Van de Ven, James

    2016-08-30

    The objective of this project was to develop one or more real-time feedback and feed-forward (MPC) control algorithms for an Oscillating Surge Wave Converter (OSWC) developed by RME called SurgeWEC™ that leverages recent innovations in wave energy converter (WEC) control theory to maximize power production in random wave environments. The control algorithms synthesized innovations in dynamic programming and nonlinear wave dynamics using anticipatory wave sensors and localized sensor measurements; e.g. position and velocity of the WEC Power Take Off (PTO), with predictive wave forecasting data. The result was an advanced control system that uses feedback or feed-forward data from an array of sensor channels comprised of both localized and deployed sensors fused into a single decision process that optimally compensates for uncertainties in the system dynamics, wave forecasts, and sensor measurement errors.

  6. Mangroves as a protection from storm surges in a changing climate.

    PubMed

    Blankespoor, Brian; Dasgupta, Susmita; Lange, Glenn-Marie

    2017-05-01

    Adaptation to climate change includes addressing sea-level rise (SLR) and increased storm surges in many coastal areas. Mangroves can substantially reduce vulnerability of the adjacent coastal land from inundation but SLR poses a threat to the future of mangroves. This paper quantifies coastal protection services of mangroves for 42 developing countries in the current climate, and a future climate change scenario with a 1-m SLR and 10  % intensification of storms. Findings demonstrate that while SLR and increased storm intensity would increase storm surge areas, the greatest impact is from the expected loss of mangroves. Under current climate and mangrove coverage, 3.5 million people and GDP worth roughly US $400 million are at risk. In the future climate change scenario, vulnerable population and GDP at risk would increase by 103 and 233  %. The greatest risk is in East Asia, especially in Indonesia and the Philippines as well as Myanmar.

  7. Large Eddy Simulation for Oscillating Airfoils with Large Pitching and Surging Motions

    NASA Astrophysics Data System (ADS)

    Kocher, Alexander; Cumming, Reed; Tran, Steven; Sahni, Onkar

    2016-11-01

    Many applications of interest involve unsteady aerodynamics due to time varying flow conditions (e.g. in the case of flapping wings, rotorcrafts and wind turbines). In this study, we formulate and apply large eddy simulation (LES) to investigate flow over airfoils at a moderate mean angle of attack with large pitching and surging motions. Current LES methodology entails three features: i) a combined subgrid scale model in the context of stabilized finite element methods, ii) local variational Germano identity (VGI) along with Lagrangian averaging, and iii) arbitrary Lagrangian-Eulerian (ALE) description over deforming unstructured meshes. Several cases are considered with different types of motions including surge only, pitch only and a combination of the two. The flow structures from these cases are analyzed and the numerical results are compared to experimental data when available.

  8. Use of Lean Response to Improve Pandemic Influenza Surge in Public Health Laboratories

    PubMed Central

    Chang, Yin; Prystajecky, Natalie; Petric, Martin; Mak, Annie; Abbott, Brendan; Paris, Benjamin; Decker, K.C.; Pittenger, Lauren; Guercio, Steven; Stott, Jeff; Miller, Joseph D.

    2012-01-01

    A novel influenza A (H1N1) virus detected in April 2009 rapidly spread around the world. North American provincial and state laboratories have well-defined roles and responsibilities, including providing accurate, timely test results for patients and information for regional public health and other decision makers. We used the multidisciplinary response and rapid implementation of process changes based on Lean methods at the provincial public health laboratory in British Columbia, Canada, to improve laboratory surge capacity in the 2009 influenza pandemic. Observed and computer simulating evaluation results from rapid processes changes showed that use of Lean tools successfully expanded surge capacity, which enabled response to the 10-fold increase in testing demands. PMID:22257385

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

    USGS Publications Warehouse

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

    2007-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  11. Lunar Phasing of the Thyroxine Surge Preparatory to Seaward Migration of Salmonid Fish

    NASA Astrophysics Data System (ADS)

    Grau, E. Gordon; Dickhoff, Walton W.; Nishioka, Richard S.; Bern, Howard A.; Folmar, Leroy C.

    1981-02-01

    Anadromous salmonid fish show a distinct surge in plasma thyroxine during the smoltification period prior to their migration to the sea. Analysis of 27 groups of hatchery-reared salmon and anadromous trout indicates that thyroxine levels peak coincident with the new moon. The ability to predict migratory readiness by lunar calendar would have substantial implications for the efficient culture of this economically important protein resource.

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

    DTIC Science & Technology

    2012-01-01

    module can be run in 3D mode, for modeling the storm surge in this study we choose to run the model in horizontal 2D mode. Wave effects are included in...we validate the DELFT3D modeling suite comprised of FLOW and WAVE modules to model inundation caused by Hurricane Ike (2008) using reanalyzed data... Model results are compared to the data collected by the SURA coastal inundation testbed. Comparing the effects of coupling waves show that there

  13. Uncertainty and feasibility of dynamical downscaling for modeling tropical cyclones for storm surge simulation

    SciTech Connect

    Yang, Zhaoqing; Taraphdar, Sourav; Wang, Taiping; Ruby Leung, L.; Grear, Molly

    2016-08-22

    This paper presents a modeling study conducted to evaluate the uncertainty of a regional model in simulating hurricane wind and pressure fields, and the feasibility of driving coastal storm surge simulation using an ensemble of region model outputs produced by 18 combinations of three convection schemes and six microphysics parameterizations, using Hurricane Katrina as a test case. Simulated wind and pressure fields were compared to observed H*Wind data for Hurricane Katrina and simulated storm surge was compared to observed high-water marks on the northern coast of the Gulf of Mexico. The ensemble modeling analysis demonstrated that the regional model was able to reproduce the characteristics of Hurricane Katrina with reasonable accuracy and can be used to drive the coastal ocean model for simulating coastal storm surge. Results indicated that the regional model is sensitive to both convection and microphysics parameterizations that simulate moist processes closely linked to the tropical cyclone dynamics that influence hurricane development and intensification. The Zhang and McFarlane (ZM) convection scheme and the Lim and Hong (WDM6) microphysics parameterization are the most skillful in simulating Hurricane Katrina maximum wind speed and central pressure, among the three convection and the six microphysics parameterizations. Error statistics of simulated maximum water levels were calculated for a baseline simulation with H*Wind forcing and the 18 ensemble simulations driven by the regional model outputs. The storm surge model produced the overall best results in simulating the maximum water levels using wind and pressure fields generated with the ZM convection scheme and the WDM6 microphysics parameterization.

  14. Hurricane Storm Surge Risk Analysis for the Development of Structures of Coastal Resilience

    NASA Astrophysics Data System (ADS)

    Mayo, T.; Lin, N.

    2014-12-01

    In this work, we use a physically based assessment to estimate the risk of hurricane storm surge at four sites along the U.S. North Atlantic coast. The sites are Narragansett Bay, RI, Jamaica Bay, NY, Atlantic City, NJ, and Norfolk, VA. These sites have all been identified as urban, coastal areas that are particularly vulnerable to storm surge. In consideration of the changing climate, we seek to assess the risk at these sites for both current and projected climate conditions. Using a novel approach to risk analysis, we estimate storm surge recurrence intervals by forcing a hydrodynamic model with thousands of hurricanes. Rather than relying on the limited historical records, we force the hydrodynamic model with the wind and pressure field data of synthetic hurricanes, which are generated from a statistical-deterministic model. This hurricane model uses large-scale atmospheric and oceanic data as input, which can be generated from global climate models (GCMs). To assess the risk of storm surge in the current climate, i.e. the 20th century, we use large-scale data of the observed climate as estimated by the NCEP/NCAR reanalysis. To assess the risk for projected climate scenarios, i.e. the 21st century, we use large-scale data modeled by four GCMs informed by the RCP8.5 emissions scenario from the Intergovernmental Panel on Climate Change fifth assessment report. In addition to the generation of these ``21st century" storms, we account for climate change by incorporating the rising mean sea level. We have also recently investigated strategies to best estimate recurrence intervals for the 21st century from the distinct recurrence intervals that result from each GCM. Our results have been used to inform a multi-institutional, interdisciplinary research effort to develop ``Structures of Coastal Resilience."

  15. KNDy Neurons Modulate the Magnitude of the Steroid-Induced Luteinizing Hormone Surges in Ovariectomized Rats.

    PubMed

    Helena, Cleyde V; Toporikova, Natalia; Kalil, Bruna; Stathopoulos, Andrea M; Pogrebna, Veronika V; Carolino, Ruither O; Anselmo-Franci, Janete A; Bertram, Richard

    2015-11-01

    Kisspeptin is the most potent stimulator of LH release. There are two kisspeptin neuronal populations in the rodent brain: in the anteroventral periventricular nucleus (AVPV) and in the arcuate nucleus. The arcuate neurons coexpress kisspeptin, neurokinin B, and dynorphin and are called KNDy neurons. Because estradiol increases kisspeptin expression in the AVPV whereas it inhibits KNDy neurons, AVPV and KNDy neurons have been postulated to mediate the positive and negative feedback effects of estradiol on LH secretion, respectively. Yet the role of KNDy neurons during the positive feedback is not clear. In this study, ovariectomized rats were microinjected bilaterally into the arcuate nucleus with a saporin-conjugated neurokinin B receptor agonist for targeted ablation of approximately 70% of KNDy neurons. In oil-treated animals, ablation of KNDy neurons impaired the rise in LH after ovariectomy and kisspeptin content in both populations. In estradiol-treated animals, KNDy ablation did not influence the negative feedback of steroids during the morning. Surprisingly, KNDy ablation increased the steroid-induced LH surges, accompanied by an increase of kisspeptin content in the AVPV. This increase seems to be due to lack of dynorphin input from KNDy neurons to the AVPV as the following: 1) microinjections of a dynorphin antagonist into the AVPV significantly increased the LH surge in estradiol-treated rats, similar to KNDy ablation, and 2) intra-AVPV microinjections of dynorphin in KNDy-ablated rats restored LH surge levels. Our results suggest that KNDy neurons provide inhibition to AVPV kisspeptin neurons through dynorphin and thus regulate the amplitude of the steroid-induced LH surges.

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

    USGS Publications Warehouse

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

    2006-01-01

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

  17. Parameters Optimization for Operational Storm Surge/Tide Forecast Model using a Genetic Algorithm

    NASA Astrophysics Data System (ADS)

    Lee, W.; You, S.; Ryoo, S.; Global Environment System Research Laboratory

    2010-12-01

    Typhoons generated in northwestern Pacific Ocean annually affect the Korean Peninsula and storm surges generated by strong low pressure and sea winds often cause serious damage to property in the coastal region. To predict storm surges, a lot of researches have been conducted by using numerical models for many years. Various parameters used for calculation of physics process are used in numerical models based on laws of physics, but they are not accurate values. Because those parameters affect to the model performance, these uncertain values can sensitively operate results of the model. Therefore, optimization of these parameters used in numerical model is essential for accurate storm surge predictions. A genetic algorithm (GA) is recently used to estimate optimized values of these parameters. The GA is a stochastic exploration modeling natural phenomenon named genetic heritance and competition for survival. To realize breeding of species and selection, the groups which may be harmed are kept and use genetic operators such as inheritance, mutation, selection and crossover. In this study, we have improved operational storm surge/tide forecast model(STORM) of NIMR/KMA (National Institute of Meteorological Research/Korea Meteorological Administration) that covers 115E - 150E, 20N - 52N based on POM (Princeton Ocean Model) with 8km horizontal resolutions using the GA. Optimized values have been estimated about main 4 parameters which are bottom drag coefficient, background horizontal diffusivity coefficient, Smagoranski’s horizontal viscosity coefficient and sea level pressure scaling coefficient within STORM. These optimized parameters were estimated on typhoon MAEMI in 2003 and 9 typhoons which have affected to Korea peninsula from 2005 to 2007. The 4 estimated parameters were also used to compare one-month predictions in February and August 2008. During the 48h forecast time, the mean and median model accuracies improved by 25 and 51%, respectively.

  18. Surge-like Oscillations above Sunspot Light Bridges Driven by Magnetoacoustic Shocks

    NASA Astrophysics Data System (ADS)

    Zhang, Jingwen; Tian, Hui; He, Jiansen; Wang, Linghua

    2017-03-01

    High-resolution observations of the solar chromosphere and transition region often reveal surge-like oscillatory activities above sunspot light bridges (LBs). These oscillations are often interpreted as intermittent plasma jets produced by quasi-periodic magnetic reconnection. We have analyzed the oscillations above an LB in a sunspot using data taken by the Interface Region Imaging Spectrograph. The chromospheric 2796 Å images show surge-like activities above the entire LB at any time, forming an oscillating wall. Within the wall we often see that the core of the Mg ii k 2796.35 Å line first experiences a large blueshift, and then gradually decreases to zero shift before increasing to a redshift of comparable magnitude. Such a behavior suggests that the oscillations are highly nonlinear and likely related to shocks. In the 1400 Å passband, which samples emission mainly from the Si iv ion, the most prominent feature is a bright oscillatory front ahead of the surges. We find a positive correlation between the acceleration and maximum velocity of the moving front, which is consistent with numerical simulations of upward propagating slow-mode shock waves. The Si iv 1402.77 Å line profile is generally enhanced and broadened in the bright front, which might be caused by turbulence generated through compression or by the shocks. These results, together with the fact that the oscillation period stays almost unchanged over a long duration, lead us to propose that the surge-like oscillations above LBs are caused by shocked p-mode waves leaked from the underlying photosphere.

  19. Human survival in volcanic eruptions: Thermal injuries in pyroclastic surges, their causes, prognosis and emergency management.

    PubMed

    Baxter, Peter J; Jenkins, Susanna; Seswandhana, Rosadi; Komorowski, Jean-Christophe; Dunn, Ken; Purser, David; Voight, Barry; Shelley, Ian

    2017-02-21

    This study of burns patients from two eruptions of Merapi volcano, Java, in 1994 and 2010, is the first detailed analysis to be reported of thermal injuries in a large series of hospitalised victims of pyroclastic surges, one of the most devastating phenomena in explosive eruptions. Emergency planners in volcanic crises in populated areas have to integrate the health sector into disaster management and be aware of the nature of the surge impacts and the types of burns victims to be expected in a worst scenario, potentially in numbers and in severity that would overwhelm normal treatment facilities. In our series, 106 patients from the two eruptions were treated in the same major hospital in Yogyakarta and a third of these survived. Seventy-eight per cent were admitted with over 40% TBSA (total body surface area) burns and around 80% of patients were suspected of having at least some degree of inhalation injury as well. Thirty five patients suffered over 80% TBSA burns and only one of these survived. Crucially, 45% of patients were in the 40-79% TBSA range, with most suspected of suffering from inhalation injury, for whom survival was most dependent on the hospital treatment they received. After reviewing the evidence from recent major eruptions and outlining the thermal hazards of surges, we relate the type and severity of the injuries of these patients to the temperatures and dynamics of the pyroclastic surges, as derived from the environmental impacts and associated eruption processes evaluated in our field surveys and interviews conducted by our multi-disciplinary team. Effective warnings, adequate evacuation measures, and political will are all essential in volcanic crises in populated areas to prevent future catastrophes on this scale.

  20. Bridging complexity theory and resilience to develop surge capacity in health systems.

    PubMed

    Therrien, Marie-Christine; Normandin, Julie-Maude; Denis, Jean-Louis

    2017-03-20

    Purpose Health systems are periodically confronted by crises - think of Severe Acute Respiratory Syndrome, H1N1, and Ebola - during which they are called upon to manage exceptional situations without interrupting essential services to the population. The ability to accomplish this dual mandate is at the heart of resilience strategies, which in healthcare systems involve developing surge capacity to manage a sudden influx of patients. The paper aims to discuss these issues. Design/methodology/approach This paper relates insights from resilience research to the four "S" of surge capacity (staff, stuff, structures and systems) and proposes a framework based on complexity theory to better understand and assess resilience factors that enable the development of surge capacity in complex health systems. Findings Detailed and dynamic complexities manifest in different challenges during a crisis. Resilience factors are classified according to these types of complexity and along their temporal dimensions: proactive factors that improve preparedness to confront both usual and exceptional requirements, and passive factors that enable response to unexpected demands as they arise during a crisis. The framework is completed by further categorizing resilience factors according to their stabilizing or destabilizing impact, drawing on feedback processes described in complexity theory. Favorable order resilience factors create consistency and act as stabilizing forces in systems, while favorable disorder factors such as diversity and complementarity act as destabilizing forces. Originality/value The framework suggests a balanced and innovative process to integrate these factors in a pragmatic approach built around the fours "S" of surge capacity to increase health system resilience.

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

    NASA Astrophysics Data System (ADS)

    Kulp, S. A.; Strauss, B.

    2015-12-01

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

  2. Implementing Extreme Value Analysis in a Geospatial Workflow for Storm Surge Hazard Assessment

    NASA Astrophysics Data System (ADS)

    Catelli, J.; Nong, S.

    2014-12-01

    Gridded data of 100-yr (1%) and 500-yr (0.2%) storm surge flood elevations for the United States, Gulf of Mexico, and East Coast are critical to understanding this natural hazard. Storm surge heights were calculated across the study area utilizing SLOSH (Sea, Lake, and Overland Surges from Hurricanes) model data for thousands of synthetic US landfalling hurricanes. Based on the results derived from SLOSH, a series of interpolations were performed using spatial analysis in a geographic information system (GIS) at both the SLOSH basin and the synthetic event levels. The result was a single grid of maximum flood elevations for each synthetic event. This project addresses the need to utilize extreme value theory in a geospatial environment to analyze coincident cells across multiple synthetic events. The results are 100-yr (1%) and 500-yr (0.2%) values for each grid cell in the study area. This talk details a geospatial approach to move raster data to SciPy's NumPy Array structure using the Python programming language. The data are then connected through a Python library to an outside statistical package like R to fit cell values to extreme value theory distributions and return values for specified recurrence intervals. While this is not a new process, the value behind this work is the ability to keep this process in a single geospatial environment and be able to easily replicate this process for other natural hazard applications and extreme event modeling.

  3. Effect of Surge Current Testing on Reliability of Solid Tantalum Capacitors

    NASA Technical Reports Server (NTRS)

    Teverovsky, Alexander

    2008-01-01

    Tantalum capacitors manufactured per military specifications are established reliability components and have less than 0.001% of failures per 1000 hours 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. To reduce this risk, further development of a screening and qualification system with special attention to the possible deficiencies in the existing procedures is necessary. The purpose of this work is evaluation of the effect of surge current stress testing on reliability of the parts at both steady-state and multiple surge current stress conditions. In order to reveal possible degradation and precipitate more failures, various part types were tested and stressed in the range of voltage and temperature conditions exceeding the specified limits. A model to estimate the probability of post-surge current testing-screening failures and measures to improve the effectiveness of the screening process has been suggested.

  4. Monitoring Inland Storm Surge and Flooding from Hurricane Ike in Texas and Louisiana, September 2008

    USGS Publications Warehouse

    East, Jeffery W.; Turco, Michael J.; Mason, Jr., Robert R.

    2008-01-01

    The U.S. Geological Survey (USGS) deployed a temporary monitoring network of 117 pressure transducers (sensors) at 65 sites over an area of about 5,000 square miles to record the timing, areal extent, and magnitude of inland hurricane storm surge and coastal flooding generated by Hurricane Ike, which struck southeastern Texas and southwestern Louisiana September 12-13, 2008. Fifty-six sites were in Texas and nine were in Louisiana. Sites were categorized as surge, riverine, or beach/wave on the basis of proximity to the Gulf Coast. One-hundred five sensors from 59 sites (fig. 1) were recovered; 12 sensors from six sites either were lost during the storm or were not retrieved. All 59 sites (41 surge, 10 riverine, 8 beach/wave) had sensors to record water pressure (fig. 2), which is expressed as water level in feet above North American Vertical Datum of 1988 (NAVD88), and 46 sites had an additional sensor to record barometric pressure, expressed in pounds per square inch. Figure 3 shows an example of water level and barometric pressure over time recorded by sensors during the storm.

  5. Coordinated ground and space measurements of auroral surge over South Pole. Technical report

    SciTech Connect

    Rosenberg, T.J.; Detrick, D.L.; Mizera, P.F.; Gorney, D.J.; Berkey, F.T.

    1988-02-01

    Coincident ground-based and satellite observations are presented of a premidnight auroral surge over Amundsen-Scott South Pole station. The set of near-simultaneous measurements provides an excellent opportunity to gain a more-quantitative understanding of the nature of premidnight substorm activity at high geomagnetic latitudes. The surge produced a rapid onset of cosmic radio noise absorption at the station. On the polar-orbiting DMSP-F6 spacecraft, intense x-ray emissions with E > 2-keV energy were imaged 1 to 2 deg magnetically equatorward of the South Pole approximately 1 min prior to the peak of the absorption event. The precipitating electron spectrum determined from the x-ray measurements could be characterized by an e-folding energy of approx. 11 keV and is found to be adequate to account for the cosmic noise absorption and maximum auroral luminosity recorded at South Pole. Photometer, all-sky camera, riometer, and magnetometer data are used to estimate the velocity of motion and spatial extent of the auroral precipitation and the ionospheric currents associated with the surge.

  6. Coordinated ground and space measurements of an auroral surge over South Pole

    SciTech Connect

    Rosenberg, T.J.; Detrick, D.L.; Mizera, P.F.; Gorney, D.J.; Berkey, F.T.; Eather, R.H.; Lanzerotti, L.J.

    1987-10-01

    Coincident ground-based and satellite observations are presented of a premidnight auroral surge over Amundsen-Scott South Pole station. The set of near-simultaneous measurements provides an excellent opportunity to gain a more quantitative understanding of the nature of premidnight substorm activity at high geomagnetic latitudes. The surge produced a rapid onset of cosmic radio noise absorption at the station. On the polar-orbiting DMSP F6 spacecraft, intense X ray emissions with E>2 keV energy were imaged 1/sup 0/ to 2/sup 0/ magnetically equatorward of South Pole approximately 1 min prior to the peak of the absorption event. The spectrum of precipitating electrons determined from the X ray measurements could be characterized by an e-folding energy of approx.11 keV and is found to be adequate to account for the cosmic noise absorption and maximum auroral luminosity recorded at South Pole. Photometer, all-sky camera, riometer, and magnetometer data are used to estimate the velocity of motion and spatial extent of the auroral precipitation and the ionospheric currents associated with the surge. The electron precipitation region is deduced to have a latitudinal scale size of <100 km and to move poleward with a speed of approx.1--2 km/s coincident with the movement of a westward electrojet.

  7. Specific Considerations on IEC Standardization of Externally Gapped Line Surge Arresters (EGLAs)

    NASA Astrophysics Data System (ADS)

    Ishizaki, Yoshihiro; Tsuge, Kenji; Kobayashi, Misao; Izumi, Kunikazu; Kawamura, Tatsuo

    The application of externally gapped line surge arresters (EGLAs), which have been developed and established in Japan, is now expanding into many countries. Therefore, the maintenance team 4 (MT4) in the international electrotechnical commission (IEC) technical committee 37 (TC37) for surge arresters advances the standardization works to specify the minimum criteria for requirements and testing methods of EGLAs. EGLAs are effective lightning protection of overhead transmission lines, and have unique required performances originated from the external series gap. The unique required performances of EGLA are insulation coordination performance of EGLA sparkover voltage for lightning overvoltage with the insulator assembly to be protected, withstand voltage performance for switching surge overvoltage and TOV, and follow current interruption performance. This paper discusses the specific issues to be considered for the standardization, such as classification of lightning discharge current rating and a test procedure for follow current interruption performance, based on the Japanese technology through more than twenty years of experience with a large numbers of EGLAs in 22kV to 500kV systems.

  8. Dynamics of a surge observed in the C IV and H alpha lines

    NASA Technical Reports Server (NTRS)

    Schmieder, B.; Mein, P.; Vial, J.-C.; Tandberg-Hanssen, E.

    1983-01-01

    Time sequences of a surge have been obtained in Active Region 2701 during a coordinated SMY program, on October 2nd, 1980, while the MSDP spectrograph operated in H-alpha at the Meudon Solar Tower and the UVSP spectrometer on SMM observed in the 1548 A C IV resonance line. The cold (H-alpha) and hot (C IV) material follow the same channel, and the event lasts about 10 min in both lines. A good correlation is found between H-alpha and C IV velocities; radial velocities along the surge are in the range 40-60 km/s in both cases. The observations are consistent with the hypothesis that a pressure gradient drives the surge. The H-alpha data seem to indicate the presence of a shock wave in the chromosphere, while the C IV quantities (velocities, accelerations) vary on a very short time scale. Their maxima occur at some locations which could be interpreted as 'pinched' zones.

  9. Sensitivity of worst-case strom surge considering influence of climate change

    NASA Astrophysics Data System (ADS)

    Takayabu, Izuru; Hibino, Kenshi; Sasaki, Hidetaka; Shiogama, Hideo; Mori, Nobuhito; Shibutani, Yoko; Takemi, Tetsuya

    2016-04-01

    There are two standpoints when assessing risk caused by climate change. One is how to prevent disaster. For this purpose, we get probabilistic information of meteorological elements, from enough number of ensemble simulations. Another one is to consider disaster mitigation. For this purpose, we have to use very high resolution sophisticated model to represent a worst case event in detail. If we could use enough computer resources to drive many ensemble runs with very high resolution model, we can handle these all themes in one time. However resources are unfortunately limited in most cases, and we have to select the resolution or the number of simulations if we design the experiment. Applying PGWD (Pseudo Global Warming Downscaling) method is one solution to analyze a worst case event in detail. Here we introduce an example to find climate change influence on the worst case storm-surge, by applying PGWD to a super typhoon Haiyan (Takayabu et al, 2015). 1 km grid WRF model could represent both the intensity and structure of a super typhoon. By adopting PGWD method, we can only estimate the influence of climate change on the development process of the Typhoon. Instead, the changes in genesis could not be estimated. Finally, we drove SU-WAT model (which includes shallow water equation model) to get the signal of storm surge height. The result indicates that the height of the storm surge increased up to 20% owing to these 150 years climate change.

  10. A hybrid inventory management system respondingto regular demand and surge demand

    SciTech Connect

    Mohammad S. Roni; Mingzhou Jin; Sandra D. Eksioglu

    2014-06-01

    This paper proposes a hybrid policy for a stochastic inventory system facing regular demand and surge demand. The combination of two different demand patterns can be observed in many areas, such as healthcare inventory and humanitarian supply chain management. The surge demand has a lower arrival rate but higher demand volume per arrival. The solution approach proposed in this paper incorporates the level crossing method and mixed integer programming technique to optimize the hybrid inventory policy with both regular orders and emergency orders. The level crossing method is applied to obtain the equilibrium distributions of inventory levels under a given policy. The model is further transformed into a mixed integer program to identify an optimal hybrid policy. A sensitivity analysis is conducted to investigate the impact of parameters on the optimal inventory policy and minimum cost. Numerical results clearly show the benefit of using the proposed hybrid inventory model. The model and solution approach could help healthcare providers or humanitarian logistics providers in managing their emergency supplies in responding to surge demands.

  11. Contrasting NYC Coastal Restoration and Storm Surge Barrier Impacts on Flooding

    NASA Astrophysics Data System (ADS)

    Orton, P. M.; Georgas, N.; Blumberg, A. F.

    2012-12-01

    A detailed and well-validated hydrodynamic model is used to examine the potential effects of storm surge barriers and Jamaica Bay restoration on coastal flooding in New York City (NYC). The most recent flooding episode, the August 2011 tropical cyclone Irene, is utilized as a test case. Two experiments are run: (a) adding three storm surge barriers, and (b) reducing the depths of channels in Jamaica Bay towards their historical levels before extensive dredging took place. Results show that the surge barriers are an effective method for protecting the city center, but have a negative result of raising flood elevations outside the barriers. The rise is ~5% in the Jamaica Bay watershed, where most of NYC's low-lying vulnerable population is located. Shallowing Jamaica Bay reduces Irene's peak storm tide elevation by ~12% in the Bay, reduces normal high tide elevations, but also raises low tides and overall mean water levels. The reduction in storm tide flood elevations is enough to offset decades of anticipated sea level rise. In recent decades, tidal marsh islands in the Bay have been rapidly eroding. Further research should examine how the marshes would adapt to a managed long-term shallowing plan, as well as how their re-growth could provide additional flood protection.

  12. Centrifugal compressor surge detecting method based on wavelet analysis of unsteady pressure fluctuations in typical stages

    NASA Astrophysics Data System (ADS)

    Izmaylov, R.; Lebedev, A.

    2015-08-01

    Centrifugal compressors are complex energy equipment. Automotive control and protection system should meet the requirements: of operation reliability and durability. In turbocompressors there are at least two dangerous areas: surge and rotating stall. Antisurge protecting systems usually use parametric or feature methods. As a rule industrial system are parametric. The main disadvantages of anti-surge parametric systems are difficulties in mass flow measurements in natural gas pipeline compressor. The principal idea of feature method is based on the experimental fact: as a rule just before the onset of surge rotating or precursor stall established in compressor. In this case the problem consists in detecting of unsteady pressure or velocity fluctuations characteristic signals. Wavelet analysis is the best method for detecting onset of rotating stall in spite of high level of spurious signals (rotating wakes, turbulence, etc.). This method is compatible with state of the art DSP systems of industrial control. Examples of wavelet analysis application for detecting onset of rotating stall in typical stages centrifugal compressor are presented. Experimental investigations include unsteady pressure measurement and sophisticated data acquisition system. Wavelet transforms used biorthogonal wavelets in Mathlab systems.

  13. Assessing Flood Risk from Hurricane-induced Precipitation and Storm Surge: A Bayesian Network Approach

    NASA Astrophysics Data System (ADS)

    Sebastian, A.; Dupuits, E. J. C.; Morales-Napoles, O.

    2015-12-01

    Hurricanes pose a major flood hazard to communities on the U.S. Atlantic and Gulf Coasts. Over the past decade, the economic costs associated with hurricane flood damages have escalated and recent studies indicate that a large percentage of flood damages are occurring outside of FEMA-designated flood hazard areas. While FEMA recently upgraded coastal flood hazard maps using the Advanced CIRCulation (ADCIRC) Model, these maps do not consider the flood hazard resulting from the joint occurrence of precipitation over the watershed and storm surge at the coast. Instead, the two individual hazards are mapped separately, ignoring the floodplain resulting from their interaction.In this study, a risk assessment methodology was developed to predict the damages associated with hurricane-induced flooding in the Houston Galveston Bay Area. Historical hurricanes were analyzed to derive probability distributions for storm surge height, cumulative precipitation, hurricane landfall, wind speed, angle of approach, radius to maximum winds, and forward speed. A Bayesian Network was built and used to simulate a large number of synthetic storms. The resulting 1% combinations of storm surge and precipitation were applied as boundary conditions to a hydraulic modeled and the maximum extent of flooding was compared to the FEMA-designated flood hazard areas. A high resolution GIS-based model was used to predict damages.

  14. Using a geographic information system (GIS) to assess pediatric surge potential after an earthquake.

    PubMed

    Curtis, Jacqueline W; Curtis, Andrew; Upperman, Jeffrey S

    2012-06-01

    Geographic information systems (GIS) and geospatial technology (GT) can help hospitals improve plans for postdisaster surge by assessing numbers of potential patients in a catchment area and providing estimates of special needs populations, such as pediatrics. In this study, census-derived variables are computed for blockgroups within a 3-mile radius from Children's Hospital Los Angeles (CHLA) and from Los Angeles County-University of Southern California (LAC-USC) Medical Center. Landslide and liquefaction zones are overlaid on US Census Bureau blockgroups. Units that intersect with the hazard zones are selected for computation of pediatric surge potential in case of an earthquake. In addition, cartographic visualization and cluster analysis are performed on the entire 3-mile study area to identify hot spots of socially vulnerable populations. The results suggest the need for locally specified vulnerability models for pediatric populations. GIS and GT have untapped potential to contribute local specificity to planning for surge potential after a disaster. Although this case focuses on an earthquake hazard, the methodology is appropriate for an all-hazards approach. With the advent of Google Earth, GIS output can now be easily shared with medical personnel for broader application and improvement in planning.

  15. Hurricane-induced waves and storm surge modeling for the Mexican coast

    NASA Astrophysics Data System (ADS)

    Meza-Padilla, Rafael; Appendini, Christian M.; Pedrozo-Acuña, Adrián

    2015-08-01

    This paper describes the application of a third-generation wave model and a hydrodynamic model to determine extreme waves and water levels associated to the incidence of tropical cyclones along the Mexican coast. In addition to historical records and to overcome the limitation associated to data scarcity in Mexico, we employ information from 3100 synthetic events generated from a statistical/deterministic hurricane model. This enables the generation of a more robust database for the characterization of extreme water levels along the Mexican coast. The procedure incorporates a storm track modeling approach where, for each hurricane (historic and synthetic), the entire track is numerically reproduced as it crosses the ocean and makes landfall. Extreme values for both, waves and storm surge, are determined through an extreme value analysis at each mesh element, allowing for the identification of their spatial variability. Results for the Gulf of Mexico show that highest waves are expected along both the Caribbean Sea and the northern coast of the Gulf of Mexico, while extreme water levels due to storm surge are identified in the northern part of the Yucatan Peninsula. On the other hand, along the Pacific coast, extreme values for waves are identified at the central mainland Mexico while storm surge is minimal. The methodology is proved to be a good alternative in the reproduction of continuously varying tropical cyclone climatology along the Mexican coastline, and it provides a rational approach for assessing the hurricane-induced risk in coastal areas.

  16. Milk Leptin Surge and Biological Rhythms of Leptin and Other Regulatory Proteins in Breastmilk.

    PubMed

    Nozhenko, Yuriy; Asnani-Kishnani, Madhu; Rodríguez, Ana M; Palou, Andreu

    2015-01-01

    A significant number of chronic diseases are linked to perinatal nutrition, and prevention may be associated to naturally occurring components of breast milk. One key hormone in breast milk is leptin, related with the protection from obesity in the adulthood, thus knowing its changes through the day or lactation is crucial. We aimed to investigate the daily rhythms in the milk levels of leptin, together with other two related hormones, ghrelin and adiponectin, during lactation (days 5, 10 and 15) in rat dams, and the relation with morphometric parameters (dams and pups). Summarizing the main results, the existence of biological rhythms, but not daily and maybe circasemidian, was confirmed for the three hormones at the earliest period of lactation. The correlations performed generally showed a possible dependence of milk hormone levels on plasma levels at the early phase of lactation, while with the progression of lactation this dependence may fade and the hormone levels are suggested to be more dependent on mammary gland production/maturation. There was also a correlation between milk leptin and adiponectin levels, especially in the first half of lactation, suggesting a possible parallel regulation. Interestingly, we describe a milk leptin surge around the mid of lactation (at day 10) which may be related with pup's growth (males and females) and with the well-known (in the literature) plasma leptin surge in pups. All this knowledge may be crucial for future applications in the development of formula milk and in relation with the role of leptin surge during lactation.

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

    When storm surge and heavy precipitation co-occur, the potential for flooding in low-lying coastal areas is often much greater than from either in isolation. Knowing the probability of these compound events and understanding the processes driving them is essential to mitigate the associated high-impact risks. Here we determine the likelihood of joint occurrence of these two phenomena for the contiguous United States (US) and show that the risk of compound flooding is higher for the Atlantic/Gulf coast relative to the Pacific coast. We also provide evidence that the number of compound events has increased significantly over the past century at many of the major coastal cities. Long-term sea-level rise is the main driver for accelerated flooding along the US coastline; however, under otherwise stationary conditions (no trends in individual records), changes in the joint distributions of storm surge and precipitation associated with climate variability and change also augment flood potential. For New York City (NYC)--as an example--the observed increase in compound events is attributed to a shift towards storm surge weather patterns that also favour high precipitation. Our results demonstrate the importance of assessing compound flooding in a non-stationary framework and its linkages to weather and climate.

  18. Cumulative impacts of hurricanes on Florida mangrove ecosystems: Sediment deposition, storm surges and vegetation

    USGS Publications Warehouse

    Smith, T. J.; Anderson, G.H.; Balentine, K.; Tiling, G.; Ward, G.A.; Whelan, K.R.T.

    2009-01-01

    Hurricanes have shaped the structure of mangrove forests in the Everglades via wind damage, storm surges and sediment deposition. Immediate effects include changes to stem size-frequency distributions and to species relative abundance and density. Long-term impacts to mangroves are poorly understood at present. We examine impacts of Hurricane Wilma on mangroves and compare the results to findings from three previous storms (Labor Day, Donna, Andrew). Surges during Wilma destroyed ??? 1,250 ha of mangroves and set back recovery that started following Andrew. Data from permanent plots affected by Andrew and Wilma showed no differences among species or between hurricanes for stem mortality or basal area lost. Hurricane damage was related to hydro-geomorphic type of forest. Basin mangroves suffered significantly more damage than riverine or island mangroves. The hurricane by forest type interaction was highly significant. Andrew did slightly more damage to island mangroves. Wilma did significantly more damage to basin forests. This is most likely a result of the larger and more spatially extensive storm surge produced by Wilma. Forest damage was not related to amount of sediment deposited. Analyses of reports from Donna and the Labor Day storm indicate that some sites have recovered following catastrophic disturbance. Other sites have been permanently converted into a different ecosystem, namely intertidal mudflats. Our results indicate that mangroves are not in a steady state as has been recently claimed. ?? 2009 The Society of Wetland Scientists.

  19. Impact of topography on groundwater salinization due to ocean surge inundation

    NASA Astrophysics Data System (ADS)

    Yu, Xuan; Yang, Jie; Graf, Thomas; Koneshloo, Mohammad; O'Neal, Michael A.; Michael, Holly A.

    2016-08-01

    Sea-level rise and increases in the frequency and intensity of ocean surges caused by climate change are likely to exacerbate adverse effects on low-lying coastal areas. The landward flow of water during ocean surges introduces salt to surficial coastal aquifers and threatens groundwater resources. Coastal topographic features (e.g., ponds, dunes, barrier islands, and channels) likely have a strong impact on overwash and salinization processes, but are generally highly simplified in modeling studies. To understand topographic impacts on groundwater salinization, we modeled a theoretical overwash event and variable-density groundwater flow and salt transport in 3-D using the fully coupled surface and subsurface numerical simulator, HydroGeoSphere. The model simulates the coastal aquifer as an integrated system considering overland flow, coupled surface and subsurface exchange, variably saturated flow, and variable-density groundwater flow. To represent various coastal landscape types, we simulated both synthetic fields and real-world coastal topography from Delaware, USA. The groundwater salinization assessment suggested that the topographic connectivity promoting overland flow controls the volume of aquifer that is salinized. In contrast, the amount of water that can be stored in surface depressions determines the amount of seawater that infiltrates the subsurface and the time for seawater to flush from the aquifer. Our study suggests that topography has a significant impact on groundwater salinization due to ocean surge overwash, with important implications for coastal land management and groundwater vulnerability assessment.

  20. The effect of channel deepening on tides and storm surge: A case study of Wilmington, NC

    NASA Astrophysics Data System (ADS)

    Familkhalili, R.; Talke, S. A.

    2016-09-01

    In this study we investigate the hypothesis that increasing channel depth in estuaries can amplify both tides and storm surge by developing an idealized numerical model representing the 1888, 1975, and 2015 bathymetric conditions of the Cape Fear River Estuary, NC. Archival tide gauge data recovered from the U.S. National Archives indicates that mean tidal range in Wilmington has doubled to 1.55 m since the 1880s, with a much smaller increase of 0.07 m observed near the ocean boundary. These tidal changes are reproduced by simulating channel depths of 7 m (1888 condition) and 15.5 m (modern condition). Similarly, model sensitivity studies using idealized, parametric tropical cyclones suggest that the storm surge in the worst-case, CAT-5 event may have increased from 3.8 ± 0.25 m to 5.6 ± 0.6 m since the nineteenth century. The amplification in both tides and storm surge is influenced by reduced hydraulic drag caused by greater mean depths.

  1. Effect of Overhead Ground Wire Installing under Distribution Lines on Surge Arrester Failures

    NASA Astrophysics Data System (ADS)

    Sugimoto, Hitoshi

    Distribution surge arresters are often damaged by lightning strokes, in particular, winter lightning. An overhead ground wire (OGW) is one of effective measures against surge arrester failures. However, adding the conventional OGW to existing overhead power distribution lines needs the power interruption for construction as well as high costs because of installing them above phase conductors. Experimental results show that a covered conductor for distribution lines is more difficult to attract lightning than a bare conductor. Moreover, lightning strokes to distribution pole heads occupied over 90% of all lightning strokes in the observation result of lightning strokes to actual distribution lines without the conventional OGW, and lightning strokes to power lines were hardly observed. These results indicate that the pole heads shield the power lines from direct lightning strokes. Therefore the author studies the application of an OGW under the distribution lines (UGW) for reducing surge arrester failures. The lightning performance of the UGW is estimated by the Electro-Magnetic Transients Program (EMTP) and its effectiveness is demonstrated. The measure is expected to cut costs of construction and maintenance for lightning protection.

  2. Using Wind Setdown and Storm Surge on Lake Erie to Calibrate the Air-Sea Drag Coefficient

    PubMed Central

    Drews, Carl

    2013-01-01

    The air-sea drag coefficient controls the transfer of momentum from wind to water. In modeling storm surge, this coefficient is a crucial parameter for estimating the surge height. This study uses two strong wind events on Lake Erie to calibrate the drag coefficient using the Coupled Ocean Atmosphere Wave Sediment Transport (COAWST) modeling system and the the Regional Ocean Modeling System (ROMS). Simulated waves are generated on the lake with Simulating WAves Nearshore (SWAN). Wind setdown provides the opportunity to eliminate wave setup as a contributing factor, since waves are minimal at the upwind shore. The study finds that model results significantly underestimate wind setdown and storm surge when a typical open-ocean formulation without waves is used for the drag coefficient. The contribution of waves to wind setdown and storm surge is 34.7%. Scattered lake ice also increases the effective drag coefficient by a factor of 1.1. PMID:23977309

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

    PubMed

    Drews, Carl

    2013-01-01

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

  4. Climate downscaling: Local mean sea-level rise, surge and wave modelling

    NASA Astrophysics Data System (ADS)

    Wolf, J.; Lowe, J.; Howard, T.

    2012-04-01

    The investigation of future climate impacts at the coast requires sufficiently detailed projections for the nearshore waves and sea levels in both the present day and a future climate scenario, to provide an offshore boundary condition. Here we discuss the future changes in surge and wave climate forced by winds and pressures from a version of the Met Office Hadley Centre Climate model, for various greenhouse gas emission scenarios and for various climate model parameter choices. The local spatial variation in mean sea level is also taken into account, incorporating deviations from global mean sea level change caused by regional variations in ocean density and circulation. Some parts of the UK are still subject to glacial isostatic readjustment after the last ice age, counter-acting sea level rise, although this will be overwhelmed by the projected effects of sea level rise due to global warming in the 21st century, for most future emission scenarios. Model downscaling from the global coupled atmosphere-ocean model using a regional climate model is needed to provide more realistic and detailed wind simulations over the NW European continental shelf. There is large uncertainty in projected changes in storminess for the NE Atlantic region, with different climate models providing conflicting results for the future. Results from this study show that large increases in mean sea level (even up to 5 metres) have very little effect on the dynamics of extreme surge events, the primary effect being on the speed of propagation of tide and surge (Howard et al., 2010). Increasing storminess is expected to increase surge heights but more direct effects can be attributed directly to increased mean sea level. Based on the wave model results, seasonal mean and annual maximum wave heights are generally expected to increase to the SW of the UK, reduce to the north of the UK and experience little change in the southern North Sea or eastern Irish Sea. This pattern is consistent with a

  5. Development of Inundation Map for Bantayan Island, Cebu Using Delft3D-Flow Storm Surge Simulations of Typhoon Haiyan

    NASA Astrophysics Data System (ADS)

    Cuadra, Camille; Suarez, John Kenneth; Biton, Nophi Ian; Cabacaba, Krichi May; Lapidez, John Phillip; Santiago, Joy; Mahar Francisco Lagmay, Alfredo; Malano, Vicente

    2014-05-01

    On average, 20 typhoons enter the Philippine area of responsibility annually, making it vulnerable to different storm hazards. Apart from the frequency of tropical cyclones, the archipelagic nature of the country makes it particularly prone to storm surges. On 08 November 2013, Haiyan, a Category 5 Typhoon with maximum one-minute sustained wind speed of 315 kph, hit the central region of the Philippines. In its path, the howler devastated Bantayan Island, a popular tourist destination. The island is located north of Cebu City, the second largest metropolis of the Philippines in terms of populace. Having been directly hit by Typhoon Haiyan, Bantayan Island was severely damaged by strong winds and storm surges, with more than 11,000 houses totally destroyed while 5,000 more suffered minor damage. The adverse impacts of possible future storm surge events in the island can only be mitigated if hazard maps that depict inundation of the coastal areas of Bantayan are generated. To create such maps, Delft3D-Flow, a hydrodynamic model was used to simulate storm surges. These simulations were made over a 10-m per pixel resolution Digital Elevation Model (DEM) and the General Bathymetric Chart of the Oceans (GEBCO) bathymetry. The results of the coastal inundation model for Typhoon Haiyan's storm surges were validated using data collected from field work and local government reports. The hydrodynamic model of Bantayan was then calibrated using the field data and further simulations were made with varying typhoon tracks. This was done to generate scenarios on the farthest possible inland incursion of storm surges. The output of the study is a detailed storm surge inundation map that depicts safe zones for development of infrastructure near coastal areas and for construction of coastal protection structures. The storm surge inundation map can also be used as basis for disaster preparedness plans of coastal communities threatened by approaching typhoons.

  6. Purple Pitcher Plant (Sarracenia rosea) Dieback and Partial Community Disassembly following Experimental Storm Surge in a Coastal Pitcher Plant Bog

    PubMed Central

    Abbott, Matthew J.; Battaglia, Loretta L.

    2015-01-01

    Sea-level rise and frequent intense hurricanes associated with climate change will result in recurrent flooding of inland systems such as Gulf Coastal pitcher plant bogs by storm surges. These surges can transport salt water and sediment to freshwater bogs, greatly affecting their biological integrity. Purple pitcher plants (Sarracenia rosea) are Gulf Coast pitcher plant bog inhabitants that could be at a disadvantage under this scenario because their pitcher morphology may leave them prone to collection of saline water and sediment after a surge. We investigated the effects of storm surge water salinity and sediment type on S. rosea vitality, plant community structure, and bog soil-water conductivity. Plots (containing ≥1 ramet of S. rosea) were experimentally flooded with fresh or saline water crossed with one of three sediment types (local, foreign, or no sediment). There were no treatment effects on soil-water conductivity; nevertheless, direct exposure to saline water resulted in significantly lower S. rosea cover until the following season when a prescribed fire and regional drought contributed to the decline of all the S. rosea to near zero percent cover. There were also significant differences in plant community structure between treatments over time, reflecting how numerous species increased in abundance and a few species decreased in abundance. However, in contrast to S. rosea, most of the other species in the community appeared resilient to the effects of storm surge. Thus, although the community may be somewhat affected by storm surge, those few species that are particularly sensitive to the storm surge disturbance will likely drop out of the community and be replaced by more resilient species. Depending on the longevity of these biological legacies, Gulf Coastal pitcher plant bogs may be incapable of fully recovering if they become exposed to storm surge more frequently due to climate change. PMID:25874369

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

    PubMed

    Abbott, Matthew J; Battaglia, Loretta L

    2015-01-01

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

  8. Liftoff of the 18 May 1980 surge of Mount St. Helens (USA) and the deposits left behind

    NASA Astrophysics Data System (ADS)

    Gardner, James E.; Andrews, Benjamin J.; Dennen, Robert

    2017-01-01

    The distance that ground-hugging pyroclastic density currents travel is limited partly by when they reverse buoyancy and liftoff into the atmosphere. It is not clear, however, what deposits are left behind by lofting flows. One current that was seen to liftoff was the surge erupted from Mount St. Helens on the morning of 18 May 1980. Before lofting, it had leveled a large area of thick forest (the blowdown zone). The outer edge of the devastated area—where trees were scorched but left standing (the scorched zone)—is where the surge is thought to have lifted off. Deposits in the outer parts of the blowdown and in the scorched zone were examined at 32 sites. The important finding is that the laterally moving surge traveled through the scorched zone, and hence, the change in tree damage does not mark the runout distance of the surge. Buoyancy reversal and liftoff are thus not preserved in the deposits where the surge lofted upwards. We propose, based on interpretation of eyewitness accounts and the impacts of the surge on trees and vehicles, that the surge consisted of a faster, dilute "overcurrent" and a slower "undercurrent," where most of the mass (and heat) was retained. Reasonable estimates for flow density and velocity show that dynamic pressure of the surge (i.e., its ability to topple trees) peaked near the base of the overcurrent. We propose that where the overcurrent began to liftoff, the height of peak dynamic pressure rose above the trees and stopped toppling them. The slower undercurrent continued forward, however, scorching trees, but lacked the dynamic pressure needed to topple them. Grain-size variations argue that it slowed from ˜30 m s-1 when it entered the scorched zone to ˜3 m s-1 at the far end.

  9. Temporal relationships between minor, preovulatory, or periovulatory FSH surges and the emergence and development of 2-mm follicles of wave 1 in Bos taurus heifers.

    PubMed

    Baldrighi, J M; Siddiqui, M A R; Ginther, O J

    2016-10-01

    The number and day of emergence (first detection) of 2-mm follicles and the number and day when the 2-mm follicles reached 3-, 4-, 5-, and 6-mm during wave 1 were determined every 0.5 d (n = 9 heifers). Emergence of the follicles at each of the indicated diameters was normalized to the beginning and ending nadir and the peak of each of a minor FSH surge, the preovulatory surge, and the periovulatory surge. Relative to the day of ovulation (day 0), the minor FSH surge, preovulatory surge, and periovulatory surge encompassed (nadir to nadir) days -7.0 to -2.5 (peak, day -4.0), days -2.5 to -0.5 (peak, day -1.0), and days -0.5 to 4 (peak, day 0), respectively. Distinct mean nadirs occurred between the minor and preovulatory surges and between the preovulatory and periovulatory surges. A small percentage of 2-mm follicles (12%) and 3-mm follicles (2%) emerged during the minor FSH surge. The 4-mm follicles emerged during the preovulatory surge (24% of follicles) and periovulatory surge (76%). The 5-mm and 6-mm follicles emerged only during the periovulatory surge. The first increase (P < 0.05) in number of 2-, 3-, and 4-mm follicles began at 1.5, 1.0, and 0 d, respectively, before the nadir at the beginning of the preovulatory surge. The first increase (P < 0.05) in number of 5- and 6-mm follicles began at 0.5 and 0 d, respectively, before the intervening nadir between the preovulatory and periovulatory surges. Results demonstrated that each of the 3 surges including the minor surge contributed to the emergence of follicles at various diameters during wave 1. The emergence of 2-mm follicles during the descending portion of the minor surge indicated that smaller follicles (eg, 1 mm) apparently emerged during the major portion of the minor surge. The increasing diameter of the 2 largest follicles was not interrupted during the distinct intervening nadir between the preovulatory and periovulatory FSH surges.

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

    USGS Publications Warehouse

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

    2010-01-01

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

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

    USGS Publications Warehouse

    Frazier, T.G.; Wood, N.; Yarnal, B.; Bauer, D.H.

    2010-01-01

    Although the potential for hurricanes under current climatic conditions continue to threaten coastal communities, there is concern that climate change, specifically potential increases in sea level, could influence the impacts of future hurricanes. To examine the potential effect of sea level rise on community vulnerability to future hurricanes, we assess variations in socioeconomic exposure in Sarasota County, FL, to contemporary hurricane storm-surge hazards and to storm-surge hazards enhanced by sea level rise scenarios. Analysis indicates that significant portions of the population, economic activity, and critical facilities are in contemporary and future hurricane storm-surge hazard zones. The addition of sea level rise to contemporary storm-surge hazard zones effectively causes population and asset (infrastructure, natural resources, etc) exposure to be equal to or greater than what is in the hazard zone of the next higher contemporary Saffir-Simpson hurricane category. There is variability among communities for this increased exposure, with greater increases in socioeconomic exposure due to the addition of sea level rise to storm-surge hazard zones as one progresses south along the shoreline. Analysis of the 2050 comprehensive land use plan suggests efforts to manage future growth in residential, economic and infrastructure development in Sarasota County may increase societal exposure to hurricane storm-surge hazards. ?? 2010 Elsevier Ltd.

  12. Experimental Investigation of Acceleration Characteristics of a Turbojet Engine Including Regions of Surge and Stall for Control Applications

    NASA Technical Reports Server (NTRS)

    Stiglic, Paul M; Schmidt, Ross D; Delio, Gene J

    1954-01-01

    The acceleration characteristics, in the region of maximum acceleration and compressor stall and surge, of an axial-flow turbojet engine with a fixed-area exhaust nozzle were determined by subjecting the engine to fuel flow steps, ramps, and ramps with a sine wave superimposed. From the data obtained, the effectiveness of an optimalizer type of control for this engine was evaluated. At all speeds above 40 percent of rated, a maximum acceleration was not obtained until the engine reached the point of stall or surge. A sharp drop, as high as 80 percent of maximum, in acceleration then occurred as the compressor entered surge of stall. With the maximum acceleration occurring at the point of surge or stall, the optimalizer-type control could not prevent the engine from entering surge or stall. Effective operation of the control may still be possible by sensing the sharp drop in acceleration experienced at the point of stall or surge and using this signal to limit fuel flow. The success of this type of operation would depend on the magnitude of the stall-recovery hysteresis.

  13. Using a High-Resolution Global Climate Model to Simulate Extratropical Cyclones with Large Storm Surge Potential

    NASA Astrophysics Data System (ADS)

    Alpert, A. J.; Broccoli, A. J.; Kapnick, S. B.

    2014-12-01

    The storm surge caused by Hurricane Sandy triggered a need for new research on surge inundation and associated risk. However, observational records of coastal water levels are limited, which increases uncertainty in risk analysis. Global climate models provide a means of simulating a much larger sample of potential surge-producing events, allowing for better resolution of the tail of the frequency distribution. The resolution of current climate models may be sufficient to simulate the structure and intensity of extratropical cyclones. Since 17 of the 20 greatest storm surge events at The Battery in New York City occurred in association with extratropical cyclones, we examine the ability of a coupled atmosphere-ocean general circulation model with 50 km atmospheric resolution (the GFDL CM2.5 model) to realistically simulate extratropical cyclones in the western North Atlantic Ocean that are capable of producing large storm surges. We analyze the similarities between CM2.5 and reanalysis products, including NASA's MERRA (Modern-Era Retrospective analysis for Research and Applications). After considering differences in spatial and temporal resolution, preliminary analyses suggest that indicators of cyclone strength in CM2.5 and MERRA are comparable. We also investigate a simple screening method based on wind speed and direction to identify potential surge-producing events in CM2.5 for determining a subset of events for more detailed analysis.

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

    NASA Astrophysics Data System (ADS)

    Santiago, J. T.

    2015-12-01

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

  15. a 24/7 High Resolution Storm Surge, Inundation and Circulation Forecasting System for Florida Coast

    NASA Astrophysics Data System (ADS)

    Paramygin, V.; Davis, J. R.; Sheng, Y.

    2012-12-01

    A 24/7 forecasting system for Florida is needed because of the high risk of tropical storm surge-induced coastal inundation and damage, and the need to support operational management of water resources, utility infrastructures, and fishery resources. With the anticipated climate change impacts, including sea level rise, coastal areas are facing the challenges of increasing inundation risk and increasing population. Accurate 24/7 forecasting of water level, inundation, and circulation will significantly enhance the sustainability of coastal communities and environments. Supported by the Southeast Coastal Ocean Observing Regional Association (SECOORA) through NOAA IOOS, a 24/7 high-resolution forecasting system for storm surge, coastal inundation, and baroclinic circulation is being developed for Florida using CH3D Storm Surge Modeling System (CH3D-SSMS). CH3D-SSMS is based on the CH3D hydrodynamic model coupled to a coastal wave model SWAN and basin scale surge and wave models. CH3D-SSMS has been verified with surge, wave, and circulation data from several recent hurricanes in the U.S.: Isabel (2003); Charley, Dennis and Ivan (2004); Katrina and Wilma (2005); Ike and Fay (2008); and Irene (2011), as well as typhoons in the Pacific: Fanapi (2010) and Nanmadol (2011). The effects of tropical cyclones on flow and salinity distribution in estuarine and coastal waters has been simulated for Apalachicola Bay as well as Guana-Tolomato-Matanzas Estuary using CH3D-SSMS. The system successfully reproduced different physical phenomena including large waves during Ivan that damaged I-10 Bridges, a large alongshore wave and coastal flooding during Wilma, salinity drop during Fay, and flooding in Taiwan as a result of combined surge and rain effect during Fanapi. The system uses 4 domains that cover entire Florida coastline: West, which covers the Florida panhandle and Tampa Bay; Southwest spans from Florida Keys to Charlotte Harbor; Southeast, covering Biscayne Bay and Miami and

  16. The Dorsomedial Suprachiasmatic Nucleus Times Circadian Expression of Kiss1 and the Luteinizing Hormone Surge

    PubMed Central

    Smarr, Benjamin L.; Morris, Emma

    2012-01-01

    Ovulation in mammals is gated by a master circadian clock in the suprachiasmatic nucleus (SCN). GnRH neurons represent the converging pathway through which the brain triggers ovulation, but precisely how the SCN times GnRH neurons is unknown. We tested the hypothesis that neurons expressing kisspeptin, a neuropeptide coded by the Kiss1 gene and necessary for the activation of GnRH cells during ovulation, represent a relay station for circadian information that times ovulation. We first show that the circadian increase of Kiss1 expression, as well as the activation of GnRH cells, relies on intact ipsilateral neural input from the SCN. Second, by desynchronizing the dorsomedial (dm) and ventrolateral (vl) subregions of the SCN, we show that a clock residing in the dmSCN acts independently of the light-dark cycle, and the vlSCN, to time Kiss1 expression in the anteroventral periventricular nucleus of the hypothalamus and that this rhythm is always in phase with the LH surge. In addition, we show that although the timing of the LH surge is governed by the dmSCN, its amplitude likely depends on the phase coherence between the vlSCN and dmSCN. Our results suggest that whereas dmSCN neuronal oscillators are sufficient to time the LH surge through input to kisspeptin cells in the anteroventral periventricular nucleus of the hypothalamus, the phase coherence among dmSCN, vlSCN, and extra-SCN oscillators is critical for shaping it. They also suggest that female reproductive disorders associated with nocturnal shift work could emerge from the desynchronization between subregional oscillators within the master circadian clock. PMID:22454148

  17. Heinrich-type glacial surges in a low-order dynamical climate model

    SciTech Connect

    Verbitsky, M.; Saltzman, B.

    1994-07-01

    Recent studies suggest the occurrence of sporadic episodes during which the ice streams that discharge ice sheets become enormously active, producing large numbers of icebergs (reflected in North Atlantic sea cores as {open_quotes}Heinrich events{close_quotes}) and possibly causing the partial collapse of the ice sheets. To simulate the mechanism of implied internal thermo-hydrodynamical instability in the context of a more general paleoclimate dynamics model (PDM), a new sliding-catastrophe function that can account for ice-sheet surges in terms of the thickness, density, viscosity, heat-capacity. and heat-conductivity of ice is introduced. Analysis suggests these events might be of three possible kinds: the first occurs in periods of glacial maximum when temperature conditions on the ice surface are extremely cold, but internal friction within bottom boundary layer is also at its maximum and is strong enough to melt ice and cause its surge. The second may happen during an interglacial, when the ice thickness is small but relatively warm climate conditions on the upper surface of ice can be easily advected with the flow of ice to the bottom where even a small additional heating due to friction may cause melting. The third and, perhaps, most interesting type is one that may occur during ice sheet growth: in this period particles of ice reaching the bottom {open_quotes}remember{close_quotes} the warm temperature conditions of the previous interglacial and additional heating due to increasing friction associated with the growing ice sheet may again cause melting. This third introduces the interesting possibility that earlier CO{sub 2} concentrations may be as important for the present-day climate as its current value. According to our model the climate system seems more vulnerable to surges during the penultimate interglacial period than in present one contributing to an explanation of the recent results of the Greenland Ice Core Project. 18 refs., 3 figs., 1 tab.

  18. Chaotic Behaviuor of the Navier-Stokes Solutions, Gyroscopes and Storm Surging

    NASA Astrophysics Data System (ADS)

    Tchiguirinskaia, Ioulia; Schertzer, Daniel

    2015-04-01

    Storm surges are phenomena inflicting wide damages all over the planet. Unfortunately they are badly represented in classical forecast model schemes because their multiscale nature is at odd with the scale truncation of these models. For similar reasons, classical data analysis often compelled to considered them as 'outliers' of the normal atmospheric activity, whereas as in fact they result from the same physical mechanisms that create less extreme behavior. A better representation of storm surges requires a multicale understanding of how a cascade of seemingly harmless instabilities can generate major ones. This correspond to the conjectured, outstanding intermittency.of the chaotic behaviour of the Navier-Stokes solutions. However, our limited, mathematical understanding of the Navier-Stokes equations prevent us to directly use them to investigate this question. We therefore use the most relevant cascade model to theoretically tackle this question of intermittency, i.e. the Scaling Gyroscopes Cascade (SGC). Indeed, this model is obtained with the help of a non trivial tree-decomposition of the Lie structure of the Navier-Stokes equations. the SGC model is deduced from these equations by preserving only a certain type of direct interactions, while the resulting indirect interactions are built dynamically along the tree-structure of the cascade. Because its fundamental element corresponds to a 'top' -i.e., an object with which almost anyone began to discover the puzzling nonlinear properties of rotation!- the SGC model remains rather simple, yet not simplistic! In particular, the SGC model enables us to investigate in details the occurrence of the critical singularity of a first order multifractal phase transition, which theoretically define storm surges. Overall, these theoretical findings could significantly reduce numerous uncertainties of environmental risk assessments.

  19. Research Resource: Preovulatory LH Surge Effects on Follicular Theca and Granulosa Transcriptomes

    PubMed Central

    Gunewardena, Sumedha; Hong, Xiaoman; Spitschak, Marion; Baufeld, Anja

    2013-01-01

    The molecular mechanisms that regulate the pivotal transformation processes observed in the follicular wall following the preovulatory LH surge, are still not established, particularly for cells of the thecal layer. To elucidate thecal cell (TC) and granulosa cell (GC) type-specific biologic functions and signaling pathways, large dominant bovine follicles were collected before and 21 hours after an exogenous GnRH-induced LH surge. Antral GCs (aGCs; aspirated by follicular puncture) and membrane-associated GCs (mGCs; scraped from the follicular wall) were compared with TC expression profiles determined by mRNA microarrays. Of the approximately 11 000 total genes expressed in the periovulatory follicle, only 2% of thecal vs 25% of the granulosa genes changed in response to the LH surge. The majority of the 203 LH-regulated thecal genes were also LH regulated in GCs, leaving a total of 57 genes as LH-regulated TC-specific genes. Of the 57 thecal-specific LH-regulated genes, 74% were down-regulated including CYP17A1 and NR5A1, whereas most other genes are being identified for the first time within theca. Many of the newly identified up-regulated thecal genes (eg, PTX3, RND3, PPP4R4) were also up-regulated in granulosa. Minimal expression differences were observed between aGCs and mGCs; however, transcripts encoding extracellular proteins (NID2) and matrix modulators (ADAMTS1, SASH1) dominated these differences. We also identified large numbers of unknown LH-regulated GC genes and discuss their putative roles in ovarian function. This Research Resource provides an easy-to-access global evaluation of LH regulation in TCs and GCs that implicates numerous molecular pathways heretofore unknown within the follicle. PMID:23716604

  20. The dorsomedial suprachiasmatic nucleus times circadian expression of Kiss1 and the luteinizing hormone surge.

    PubMed

    Smarr, Benjamin L; Morris, Emma; de la Iglesia, Horacio O

    2012-06-01

    Ovulation in mammals is gated by a master circadian clock in the suprachiasmatic nucleus (SCN). GnRH neurons represent the converging pathway through which the brain triggers ovulation, but precisely how the SCN times GnRH neurons is unknown. We tested the hypothesis that neurons expressing kisspeptin, a neuropeptide coded by the Kiss1 gene and necessary for the activation of GnRH cells during ovulation, represent a relay station for circadian information that times ovulation. We first show that the circadian increase of Kiss1 expression, as well as the activation of GnRH cells, relies on intact ipsilateral neural input from the SCN. Second, by desynchronizing the dorsomedial (dm) and ventrolateral (vl) subregions of the SCN, we show that a clock residing in the dmSCN acts independently of the light-dark cycle, and the vlSCN, to time Kiss1 expression in the anteroventral periventricular nucleus of the hypothalamus and that this rhythm is always in phase with the LH surge. In addition, we show that although the timing of the LH surge is governed by the dmSCN, its amplitude likely depends on the phase coherence between the vlSCN and dmSCN. Our results suggest that whereas dmSCN neuronal oscillators are sufficient to time the LH surge through input to kisspeptin cells in the anteroventral periventricular nucleus of the hypothalamus, the phase coherence among dmSCN, vlSCN, and extra-SCN oscillators is critical for shaping it. They also suggest that female reproductive disorders associated with nocturnal shift work could emerge from the desynchronization between subregional oscillators within the master circadian clock.

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

    NASA Astrophysics Data System (ADS)

    Bowman, M. J.

    2015-12-01

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

  2. Development of a HTSMA-Actuated Surge Control Rod for High-Temperature Turbomachinery Applications

    NASA Technical Reports Server (NTRS)

    Padula, Santo, II; Noebe, Ronald; Bigelow, Glen; Culley, Dennis; Stevens, Mark; Penney, Nicholas; Gaydosh, Darrell; Quackenbush, Todd; Carpenter, Bernie

    2007-01-01

    In recent years, a demand for compact, lightweight, solid-state actuation systems has emerged, driven in part by the needs of the aeronautics industry. However, most actuation systems used in turbomachinery require not only elevated temperature but high-force capability. As a result, shape memory alloy (SMA) based systems have worked their way to the forefront of a short list of viable options to meet such a technological challenge. Most of the effort centered on shape memory systems to date has involved binary NiTi alloys but the working temperatures required in many aeronautics applications dictate significantly higher transformation temperatures than the binary systems can provide. Hence, a high temperature shape memory alloy (HTSMA) based on NiTiPdPt, having a transformation temperature near 300 C, was developed. Various thermo-mechanical processing schemes were utilized to further improve the dimensional stability of the alloy and it was later extruded/drawn into wire form to be more compatible with envisioned applications. Mechanical testing on the finished wire form showed reasonable work output capability with excellent dimensional stability. Subsequently, the wire form of the alloy was incorporated into a benchtop system, which was shown to provide the necessary stroke requirements of approx.0.125 inches for the targeted surge-control application. Cycle times for the actuator were limited to 4 seconds due to control and cooling constraints but this cycle time was determined to be adequate for the surge control application targeted as the primary requirement was initial actuation of a surge control rod, which could be completed in approximately one second.

  3. Projections of storm surges over Sunda Shelf for the future climate

    NASA Astrophysics Data System (ADS)

    Tkalich, Pavel; Luu, Quang-Hung; Kolomiets, Pavlo; Zheleznyak, Mark

    2014-05-01

    Sunda Shelf is a southeast extension of the continental shelf of Southeast Asia. Large part of the Sunda Shelf geographically belongs to the South-China Sea (SCS). Our focus is on Gulf of Thailand and Eastern coast of Malay Peninsula, where sea level extremes up to 80 cm are predominantly generated by storm surges being driven by strong winds over SCS. According to Intergovernmental Panel on Climate Change Fourth Assessment Report (IPCC AR4) the future climate extremes are projected to increase on a back of mean sea level rise, that may lead to increase of sea level extremes in the domain. In this study, a spherical shallow water equation model is applied to estimate sea level extremes due to a combined effect of tides and storm surges over the Sunda Shelf. After calibration using observational data for the past periods 1961-1990 and 1981-2010, the model is applied for the 21st century projections using selected IPCC AR4 scenarios. The model is driven by the downscaled wind and pressure from three different general circulation models (CCSM, ECHAM and MIROC) under three different climate change scenarios (A1FI, A2 and A1B), totalling in 7 runs. Statistical parameters are computed individually for subsequent 30-year eras. It is found that for all considered models, scenarios and eras, the differences between 100 and 10-year return values are within the range 25-50cm. They are higher than the corresponding difference of 20-30cm in 1961-1990 period, which we interpret as higher variability of extreme sea levels in 21st century than in 1961-1990 years. Over majority of the region, results indicate small increasing trend of storm surge intensity during northeast monsoons at initial period and decreasing trend at the end of 21st century.

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

    NASA Astrophysics Data System (ADS)

    Wahl, T.; Jain, S.; Bender, J.; Meyers, S. D.; Luther, M. E.

    2015-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

  6. Surge capacity for response to bioterrorism in hospital clinical microbiology laboratories.

    PubMed

    Shapiro, Daniel S

    2003-12-01

    Surge capacity is the ability to rapidly mobilize to meet an increased demand. While large amounts of federal funding have been allocated to public health laboratories, little federal funding has been allocated to hospital microbiology laboratories. There are concerns that hospital laboratories may have inadequate surge capacities to deal with a significant bioterrorism incident. A workflow analysis of a clinical microbiology laboratory that serves an urban medical center was performed to identify barriers to surge capacity in the setting of a bioterrorism event and to identify solutions to these problems. Barriers include a national shortage of trained medical technologists, the inability of clinical laboratories to deal with a dramatic increase in the number of blood cultures, a delay while manufacturers increase production of critical products and then transport and deliver these products to clinical laboratories, and a shortage of class II biological safety cabinets. Federal funding could remedy staffing shortages by making the salaries of medical technologists comparable to those of similarly educated health care professionals and by providing financial incentives for students to enroll in clinical laboratory science programs. Blood culture bottles, and possibly continuous-monitoring blood culture instruments, should be added to the national antibiotic stockpile. Federal support must ensure that companies that manufacture essential laboratory supplies are capable of rapidly scaling up production. Hospitals must provide increased numbers of biological safety cabinets and amounts of space dedicated to clinical microbiology laboratories. Laboratories should undertake limited cross-training of technologists, ensure that adequate packaging supplies are available, and be able to move to a 4-day blood culture protocol.

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

    USGS Publications Warehouse

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

    2014-01-01

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

  8. Estimating tsunami inundation from hurricane storm surge predictions along the U.S. gulf coast

    NASA Astrophysics Data System (ADS)

    Pampell-Manis, Alyssa; Horrillo, Juan; Figlus, Jens

    2016-08-01

    Gulf of Mexico (GOM) coasts have been included in the U.S. Tsunami Warning System since 2005. While the tsunami risk for the GOM is low, tsunamis generated by local submarine landslides pose the greatest potential threat, as evidenced by several large ancient submarine mass failures identified in the northern GOM basin. Given the lack of significant historical tsunami evidence in the GOM, the potential threat of landslide tsunamis in this region is assessed from a worst-case scenario perspective based on a set of events including the large ancient failures and most likely extreme events determined by a probabilistic approach. Since tsunamis are not well-understood along the Gulf Coast, we investigate tsunami inundation referenced to category-specific hurricane storm surge levels, which are relatively well established along the Gulf Coast, in order to provide information for assessing the potential threat of tsunamis which is more understandable and accessible to emergency managers. Based on tsunami inundation studies prepared for the communities of South Padre Island, TX, Galveston, TX, Mobile, AL, Panama City, FL, and Tampa, FL, we identify regional trends of tsunami inundation in terms of modeled storm surge inundation. The general trends indicate that tsunami inundation can well exceed the level of storm surge from major hurricanes in open beachfront and barrier island regions, while more interior areas are less threatened. Such information can be used to better prepare for tsunami events as well as provide a preliminary estimate of tsunami hazard in locations where detailed tsunami inundation studies have not been completed.

  9. Storm surge simulation along the U.S. East and Gulf Coasts using a multi-scale numerical model approach

    NASA Astrophysics Data System (ADS)

    Xu, Hongzhou; Zhang, Keqi; Shen, Jian; Li, Yuepeng

    2010-12-01

    The effectiveness of simulating surge inundation using the Eulerian-Lagrangian circulation (ELCIRC) model over multi-scale unstructured grids was examined in this study. The large domain model grid encompasses the western North Atlantic Ocean, the Gulf of Mexico, and the Caribbean Sea to appropriately account for remote and resonance effects during hurricane events and simplify the specification of the open boundary condition. The U.S. East and Gulf Coasts were divided into 12 overlapping basins with fine-resolution (up to 30 × 30 m) grids to model overland surge flooding. These overlapping basins have different fine-resolution grids near the coastal region, but have an identical coarse-resolution grid in the offshore region within the large model domain. Thus, the storm surge prediction can be conducted without reducing computation efficiency by executing multiple model runs with local fine-resolution grids where potential hurricane landfalls may occur. The capability of the multi-scale approach was examined by simulating storm surge caused by Hurricanes Andrew (1992) and Isabel (2003) along the South Florida coast and in the Chesapeake Bay. Comparisons between simulated and observed results suggest that multi-scale models proficiently simulated storm surges in the Biscayne Bay and the Chesapeake Bay during two hurricanes. A series of sensitivity tests demonstrated that the simulation of surge flooding was improved when LiDAR topographic data and special bottom drag coefficient values for mangrove forests were employed. The tests also showed that appropriate representation of linear hydrologic features is important for computing surge inundation in an urban area.

  10. Identification of Critical Vulnerable Areas During a Typhoon Haiyan Event in the Metro Manila Area Using Storm Surge Hazard Maps

    NASA Astrophysics Data System (ADS)

    Briones, J. B. L. T.; Puno, J. V.; Lapidez, J. P. B.; Muldong, T. M. M.; Ramos, M. M.; Caro, C. V.; Ladiero, C.; Bahala, M. A.; Suarez, J. K. B.; Santiago, J. T.

    2014-12-01

    Sudden rises in sea water over and above astronomical tides due to an approaching storm are known as storm surges. The development of an early warning system for storm surges is imperative, due to the high threat level of these events; Typhoon Haiyan in 08 November 2013 generated storm surges that caused casualties of over 6,000. Under the Department of Science and Technology, the Nationwide Operational Assessment of Hazards (DOST - Project NOAH) was tasked to generate storm surge hazard maps for all the coastal areas in the Philippines. The objective of this paper is to create guidelines on how to utilize the storm surge hazard map as a tool for planning and disaster mitigation. This study uses the case of the hypothetical situation in which a tropical storm with an intensity similar to Typhoon Haiyan hits Metro Manila. This site was chosen for various reasons, among them the economic, political, and cultural importance of Metro Manila as the location of the capital of the Philippines and the coastal bay length of the area. The concentration of residential areas and other establishments were also taken into account. Using the Japan Meteorology Association (JMA) Storm Surge Model, FLO-2D flood modelling software and the application of other GIS technology, the impact of Haiyan-strength typhoon passing through Manila was analysed. We were able to identify the population affected, number of affected critical facilities under each storm surge hazard level, and possible evacuation sites. The results of the study can be used as the basis of policies involving disaster response and mitigation by city authorities. The methods used by the study can be used as a replicable framework for the analysis of other sites in the Philippines.

  11. Experimental study on cyclic steps formed by surge-type turbidity currents

    NASA Astrophysics Data System (ADS)

    Yokokawa, M.; Shozakai, D.; Higuchi, H.; Hughes Clarke, J. E.; Izumi, N.

    2015-12-01

    Field observations of turbidity currents and seabed topography on the Squamish delta in Howe Sound, British Columbia, Canada have been undertaken which found bedwaves actively migrating in the upstream direction in channels formed on the prodelta slope (Hughes Clarke et al., 2012a; 2012b; 2014; Figure 1). Their topography and behaviour suggest that they are cyclic steps formed by the surge-type turbidity currents. There has been no experimental study to investigate the formative conditions of cyclic steps by the surge-type turbidity currents. We did preliminary experiments on the formation of cyclic steps due to the multiple surge-type density currents, and compare the morphology of the steps with those of Squamish delta. The experiments had been performed at Osaka Institute of Technology. A flume, which is 3.6 m long, 0.3 m deep and 2 cm wide, was submerged into a larger flume, which is 4 m long, 0.4 m deep and 8 cm wide, filled with water. Mixture of salt water (1.18 g/cm3) and plastic particles (1.5 g/cm3, 0.1-0.18 mm in diameter) poured into the upstream end of the inner flume by hand using a funnel. For the example introduced here, the slope of the outer flume was 1.5 degrees, and the mixtures' whole weight and volumetric concentration ranged from 310 g (3.23 vol.%) to 510 g (8.16 vol.%). These mixtures were poured 105 times, and the thickness of the deposits was measured every 50 cm by photographs. As a result, two mounds (steps) were formed ultimately, which are moving toward upstream direction. Wavelengths are 80 cm and 120 cm respectively. The two kinds of flow depth were measured from photograph, such as the whole thickness of the flow, and the thickness of the lower high-density layer. Calculating the wave steepness and non-dimensional wave number, it turns out that those values using the thickness of the lower high-density layer fall into the region very close to the Squamish data that assuming the flow depth as 0.5 m. This could lead the following

  12. Analysis and Prediction of Rainfall and Storm Surge Interactions in the Clear Creek Watershed using Unsteady-State HEC-RAS Hydraulic Modeling

    NASA Astrophysics Data System (ADS)

    Winter, Heather

    This study presents an unsteady-state hydraulic model analysis of hurricane storm surge and rainfall-runoff interactions in the Clear Creek Watershed, a basin draining into Galveston Bay and vulnerable to flooding from both intense local rainfalls and storm surge. Storm surge and rainfall-runoff have historically been modeled separately, and thus the linkage and interactions between the two during a hurricane are not completely understood. This study simulates the two processes simultaneously by using storm surge stage hydrographs as boundary conditions in the Hydrologic Engineering Center’s - River Analysis System (HEC-RAS) hydraulic model. Storm surge hydrographs for a severe hurricane were generated in the Advanced Circulation Model for Oceanic, Coastal, and Estuarine Waters (ADCIRC) model to predict the flooding that could be caused by a worst-case scenario. Using this scenario, zones have been identified to represent areas in the Clear Creek Watershed vulnerable to flooding from storm surge, rainfall, or both.

  13. Application of computer-assisted mapping to volcanic hazard evaluation of surge eruptions: Vulcano, lipari, and vesuvius

    NASA Astrophysics Data System (ADS)

    Sheridan, Michael F.; Malin, Michael C.

    1983-09-01

    A previously developed computer-assisted model has been applied to several pyroclastic-surge eruptions at three active volcanoes in Italy. Model hazard maps created for various vent locations, eruption types, and mass production rates reasonably reproduced pyroclastic-surge deposits from several recent eruptions on Vulcano, Lipari, and Vesuvius. Small-scale phreatic eruptions on the island of Vulcano (e.g. the 1727 explosion of Forgia Vecchia) pose a limited but serious threat to the village of Porto. The most dangerous zone affected by this type of eruption follows a NNW fissure system between Fossa and Vulcanello. Moderate-sized eruptions on Vulcano, such as those associated with the present Fossa Crater are a much more serious threat to Porto as well as the entire area within the caldera surrounding the cone. The less frequent surge eruptions on Lipari have been even more violent. The extreme mobility of surges like those produced from Monte Guardia (approx. 20,000 y.b.p.) and Monte Pilato would not only threaten the entire island of Lipari, but also the northern part of neighboring Vulcano. Eruptions at Vesuvius with energy and efficiency similar to that of the May 18, 1980 blast of Mount St. Helens would be still more destructive because of the great initial elevation of the summit vent. In addition, surge eruptions at Vesuvius are generally part of more complex eruption cycles that involve several other types of volcanic phenomena including Plinian fall and pyroclastic flows.

  14. Directional Analysis of the Storm Surge from Hurricane Sandy 2012, with Applications to Charleston, New Orleans, and the Philippines

    PubMed Central

    Drews, Carl; Galarneau, Thomas J.

    2015-01-01

    Hurricane Sandy in late October 2012 drove before it a storm surge that rose to 4.28 meters above mean lower low water at The Battery in lower Manhattan, and flooded the Hugh L. Carey automobile tunnel between Brooklyn and The Battery. This study examines the surge event in New York Harbor using the Weather Research and Forecasting (WRF) atmospheric model and the Coupled-Ocean-Atmosphere-Wave- Sediment Transport / Regional Ocean Modeling System (COAWST/ROMS). We present a new technique using directional analysis to calculate and display maps of a coastline's potential for storm surge; these maps are constructed from wind fields blowing from eight fixed compass directions. This analysis approximates the surge observed during Hurricane Sandy. The directional analysis is then applied to surge events at Charleston, South Carolina, New Orleans, Louisiana, and Tacloban City, the Philippines. Emergency managers could use these directional maps to prepare their cities for an approaching storm, on planning horizons from days to years. PMID:25822480

  15. A numerical study of vegetation impact on reducing storm surge by wetlands in a semi-enclosed estuary

    USGS Publications Warehouse

    Kelin, Hu; Qin, Chen; Wang, Hongqing

    2014-01-01

    Coastal wetlands play a unique role in extreme hurricane events. The impact of wetlands on storm surge depends on multiple factors including vegetation, landscape, and storm characteristics. The Delft3D model, in which vegetation effects on flow and turbulence are explicitly incorporated, was applied to the semi-enclosed Breton Sound (BS) estuary in coastal Louisiana to investigate the wetland impact. Guided by extensive field observations, a series of numerical experiments were conducted based on variations of actual vegetation properties and storm parameters from Hurricane Isaac in 2012. Both the vegetation-induced maximum surge reduction (MSR) and maximum surge reduction rate (MSRR) increased with stem height and stem density, and were more sensitive to stem height. The MSR and MSRR decreased significantly with increasing wind intensity. The MSRR was the highest with a fast-moving weak storm. It was also found that the MSRR varied proportionally to the expression involving the maximum bulk velocity and surge over the area of interest, and was more dependent on the maximum bulk surge. Both MSR and MSRR appeared to increase when the area of interest decreased from the whole BS estuary to the upper estuary. Within the range of the numerical experiments, the maximum simulated MSR and MSRR over the upper estuary were 0.7 m and 37%, respectively.

  16. Voltage Distribution of Internal Windings of Pole-Mounted Distribution Transformer by Lightning Surge and Measures for Voltage Reduction

    NASA Astrophysics Data System (ADS)

    Honda, Hideki; Asakawa, Akira; Yokoyama, Shigeru

    When steep lightning surge enters a pole-mounted distribution transformer, the voltage distribution of the internal windings is unbalanced. It is known that a layer-to-layer short or a turn-to-turn short occurs where the voltage distribution of windings is high. In this paper, the voltage distribution of the windings was measured at the primary and secondary sides of the transformer using a testing transformer. The point of the windings where the highest voltage occurred was clarified. At the primary windings, large voltage occurs at the layer nearest the primary bushing, and the possibility of breakdown at this point is high. By field test using several types of surge arrestor, it is found that the lower the operating voltage of the surge arrestor installed in the primary side, the lower the voltage occurring at the primary windings. At the secondary windings, large voltage occurs at the layer closer to the neutral terminal, and the possibility of breakdown at this point is high. The lower the operating voltage of the surge arrestor installed in the primary side, the lower the voltage occurring at the secondary windings, too. Adding the surge arrestor in the secondary side, although effectively reduce line-to-line voltage, does not effectively reduce the voltage of the secondary windings.

  17. The drumlin field and the geomorphology of the Múlajökull surge-type glacier, central Iceland

    NASA Astrophysics Data System (ADS)

    Jónsson, Sverrir Aðalsteinn; Schomacker, Anders; Benediktsson, Ívar Örn; Ingólfsson, Ólafur; Johnson, Mark D.

    2014-02-01

    Here we present a new geomorphological map of the active drumlin field and the forefield of Múlajökull, a surge-type outlet glacier, Iceland. The map is based on aerial photographs taken in 1995 and LiDAR data recorded in 2008. Mapping was done using ArcGIS 10 software on orthorectified imagery, LiDAR data and digital elevation models. The mapped landforms were initially identified on the aerial imagery and LiDAR and then ground-checked in the field. We mapped subglacial, supraglacial, ice-marginal, periglacial, and glaciofluvial landforms. The geomorphology of the Múlajökull forefield is similar to that of the forefields of other surge-type glaciers in Iceland: with a highly streamlined forefield, crevasse-fill ridges, and series of glaciotectonic end moraines. However, the large number (i.e., 110) of drumlins forming the drumlin field is unique for modern Icelandic surge-type glaciers and, as yet, unique for contemporary glaciers in general. Also apparent is that the drumlins are wider and shorter in the distal part of the drumlin field and narrower and longer in the proximal part. Hence, the mapping reveals a development of the drumlins toward a more streamlined shape of the proximal landforms that have experienced more surges. The drumlins in the drumlin field are active, i.e., they form during the modern surges of Múlajökull.

  18. Storm surge induced by hurricane Omar on the Caribbean coasts, example of the port of Deshaies in Guadeloupe

    NASA Astrophysics Data System (ADS)

    Dorville, J.-F.; Zahibo, N.

    2009-04-01

    In October, the hurricane Omar, that was in category four (SSHS) moved in the Caribbean to the south west of the Atlantic. During the night between the15th and the 16th, it runs near Guadeloupe coasts, at less than 300km. In the same time an increasing surge occurred on all the Caribbean coasts. In Guadeloupe the waves increased by 3 m of height, that is 6 or 8 times higher than normal conditions. The surge of Omar caused damaged of millions of euros in Guadeloupe. We made an observation on the exposes spots, and have pictures before and after the disaster. We determined the size and consequences of the surge of the hurricane Omar on this coasts. The measure of the sea elevation on the coast and neighboring coasts helped us to characterize the levels of the sea elevation during this surge. Measures on different points gave the characterization of the swell product by this hurricane. With a numerical model of wave propagation (SWAN), we improve our observation in the Port of Deshaies. We propose in our presentation to give a synoptic and the description of the surge of the hurricane Omar on the Guadeloupean coasts, and particularly in the town of Deshaies, that was ravaged by the flood of Omar.

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

    PubMed

    Drews, Carl; Galarneau, Thomas J

    2015-01-01

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

  20. Suspension-Driven Gravity Surges on Horizontal Surfaces: Effect of the Initial Shape

    NASA Astrophysics Data System (ADS)

    Zgheib, Nadim; Bonometti, Thomas; Balachandar, S.

    2016-11-01

    We present results from fully-resolved direct numerical simulations of canonical (axisymmetric and planar) and non-canonical (rectangular) configurations of horizontal suspension-driven gravity surges. We show that the dynamics along the initial minor and major axis of a rectangular release are roughly similar to that of a planar and axisymmetric current, respectively. However, contrary to expectation, we observe under certain conditions the final extent of the deposit from finite releases to surpass that from an equivalent planar current. This is attributed to a converging flow of the particle-laden mixture towards the initial minor axis, a behaviour that was previously reported for scalar-driven currents on uniform slopes. This flow is observed to be correlated with the travelling of a perturbation wave generated at the extremity of the longest side that reaches the front of the shortest side in a finite time. A semi-empirical explicit expression (based on established relations for planar and axisymmetric currents) is proposed to predict the extent of the deposit in the entire x-y plane. Finally we observe that for the same initial volume of a suspension-driven gravity surge, a release of larger initial horizontal aspect-ratio is able to retain particles in suspension for longer periods of time. ExxonMobil Upstream Research (EM 09296); NSF (OISE-0968313); CALMIP (P1525).

  1. Calculation of Local Stress and Fatigue Resistance due to Thermal Stratification on Pressurized Surge Line Pipe

    NASA Astrophysics Data System (ADS)

    Bandriyana, B.; Utaja

    2010-06-01

    Thermal stratification introduces thermal shock effect which results in local stress and fatique problems that must be considered in the design of nuclear power plant components. Local stress and fatique calculation were performed on the Pressurize Surge Line piping system of the Pressurize Water Reactor of the Nuclear Power Plant. Analysis was done on the operating temperature between 177 to 343° C and the operating pressure of 16 MPa (160 Bar). The stagnant and transient condition with two kinds of stratification model has been evaluated by the two dimensional finite elements method using the ANSYS program. Evaluation of fatigue resistance is developed based on the maximum local stress using the ASME standard Code formula. Maximum stress of 427 MPa occurred at the upper side of the top half of hot fluid pipe stratification model in the transient case condition. The evaluation of the fatigue resistance is performed on 500 operating cycles in the life time of 40 years and giving the usage value of 0,64 which met to the design requirement for class 1 of nuclear component. The out surge transient were the most significant case in the localized effects due to thermal stratification.

  2. Calculation of Local Stress and Fatigue Resistance due to Thermal Stratification on Pressurized Surge Line Pipe

    SciTech Connect

    Bandriyana, B.; Utaja

    2010-06-22

    Thermal stratification introduces thermal shock effect which results in local stress and fatigue problems that must be considered in the design of nuclear power plant components. Local stress and fatigue calculation were performed on the Pressurize Surge Line piping system of the Pressurize Water Reactor of the Nuclear Power Plant. Analysis was done on the operating temperature between 177 to 343 deg. C and the operating pressure of 16 MPa (160 Bar). The stagnant and transient condition with two kinds of stratification model has been evaluated by the two dimensional finite elements method using the ANSYS program. Evaluation of fatigue resistance is developed based on the maximum local stress using the ASME standard Code formula. Maximum stress of 427 MPa occurred at the upper side of the top half of hot fluid pipe stratification model in the transient case condition. The evaluation of the fatigue resistance is performed on 500 operating cycles in the life time of 40 years and giving the usage value of 0,64 which met to the design requirement for class 1 of nuclear component. The out surge transient were the most significant case in the localized effects due to thermal stratification.

  3. Lethal Thermal Impact at Periphery of Pyroclastic Surges: Evidences at Pompeii

    PubMed Central

    Mastrolorenzo, Giuseppe; Petrone, Pierpaolo; Pappalardo, Lucia; Guarino, Fabio M.

    2010-01-01

    Background The evaluation of mortality of pyroclastic surges and flows (PDCs) produced by explosive eruptions is a major goal in risk assessment and mitigation, particularly in distal reaches of flows that are often heavily urbanized. Pompeii and the nearby archaeological sites preserve the most complete set of evidence of the 79 AD catastrophic eruption recording its effects on structures and people. Methodology/Principal Findings Here we investigate the causes of mortality in PDCs at Pompeii and surroundings on the bases of a multidisciplinary volcanological and bio-anthropological study. Field and laboratory study of the eruption products and victims merged with numerical simulations and experiments indicate that heat was the main cause of death of people, heretofore supposed to have died by ash suffocation. Our results show that exposure to at least 250°C hot surges at a distance of 10 kilometres from the vent was sufficient to cause instant death, even if people were sheltered within buildings. Despite the fact that impact force and exposure time to dusty gas declined toward PDCs periphery up to the survival conditions, lethal temperatures were maintained up to the PDCs extreme depositional limits. Conclusions/Significance This evidence indicates that the risk in flow marginal zones could be underestimated by simply assuming that very thin distal deposits, resulting from PDCs with poor total particle load, correspond to negligible effects. Therefore our findings are essential for hazard plans development and for actions aimed to risk mitigation at Vesuvius and other explosive volcanoes. PMID:20559555

  4. Building destruction from waves and surge on the bolivar peninsula during hurricane ike

    USGS Publications Warehouse

    Kennedy, A.; Rogers, S.; Sallenger, A.; Gravois, U.; Zachry, B.; Dosa, M.; Zarama, F.

    2011-01-01

    The Bolivar Peninsula in Texas was severely impacted by Hurricane Ike with strong winds, large waves, widespread inundation, and severe damage. This paper examines the wave and surge climate on Bolivar during the storm and the consequent survival and destruction of buildings. Emphasis is placed on differences between buildings that survived (with varying degrees of damage) and buildings that were completely destroyed. Building elevations are found to be the primary indicator of survival for areas with large waves. Here, buildings that were sufficiently elevated above waves and surge suffered relatively little structural damage, while houses at lower elevations were impacted by large waves and generally completely destroyed. In many areas, the transition from destruction to survival was over a very small elevation range of around 0.5 m. In areas where waves were smaller, survival was possible at much lower elevations. Higher houses that were not inundated still survived, but well-built houses at lower elevations could also survive as the waves were not large enough to cause structural damage. However, the transition height where waves became damaging could not be determined from this study. ?? 2011 American Society of Civil Engineers.

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

    EPA Pesticide Factsheets

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

  6. Design and Analysis for a Floating Oscillating Surge Wave Energy Converter: Preprint

    SciTech Connect

    Yu, Y. H.; Li, Y.; Hallett, K.; Hotimsky, C.

    2014-03-01

    This paper presents a recent study on the design and analysis of an oscillating surge wave energy converter. A successful wave energy conversion design requires the balance between the design performance and cost. The cost of energy is often used as the metric to judge the design of the wave energy conversion system. It is often determined based on the device power performance, the cost for manufacturing, deployment, operation and maintenance, as well as the effort to ensure the environmental compliance. The objective of this study is to demonstrate the importance of a cost driven design strategy and how it can affect a WEC design. Three oscillating surge wave energy converter (OSWEC) designs were used as the example. The power generation performance of the design was modeled using a time-domain numerical simulation tool, and the mass properties of the design were determined based on a simple structure analysis. The results of those power performance simulations, the structure analysis and a simple economic assessment were then used to determine the cost-efficiency of selected OSWEC designs. Finally, a discussion on the environmental barrier, integrated design strategy and the key areas that need further investigation is also presented.

  7. Superhydrophobic SAM Modified Electrodes for Enhanced Current Limiting Properties in Intrinsic Conducting Polymer Surge Protection Devices.

    PubMed

    Jabarullah, Noor H; Verrelli, Emanuele; Mauldin, Clayton; Navarro, Luis A; Golden, Josh H; Madianos, Leonidas M; Kemp, Neil T

    2015-06-09

    Surface interface engineering using superhydrophobic gold electrodes made with 1-dodecanethiol self-assembled monolayer (SAM) has been used to enhance the current limiting properties of novel surge protection devices based on the intrinsic conducting polymer, polyaniline doped with methanesulfonic acid. The resulting devices show significantly enhanced current limiting characteristics, including current saturation, foldback, and negative differential effects. We show how SAM modification changes the morphology of the polymer film directly adjacent to the electrodes, leading to the formation of an interfacial compact thin film that lowers the contact resistance at the Au-polymer interface. We attribute the enhanced current limiting properties of the devices to a combination of lower contact resistance and increased Joule heating within this interface region which during a current surge produces a current blocking resistive barrier due to a thermally induced dedoping effect caused by the rapid diffusion of moisture away from this region. The effect is exacerbated at higher applied voltages as the higher temperature leads to stronger depletion of charge carriers in this region, resulting in a negative differential resistance effect.

  8. Revealing glacier flow and surge dynamics from animated satellite image sequences: examples from the Karakoram

    NASA Astrophysics Data System (ADS)

    Paul, F.

    2015-04-01

    Although animated images are very popular on the Internet, they have so far found only limited use for glaciological applications. With long time-series of satellite images becoming increasingly available and glaciers being well recognized for their rapid changes and variable flow dynamics, animated sequences of multiple satellite images reveal glacier dynamics in a time-lapse mode, making the otherwise slow changes of glacier movement visible and understandable for a wide public. For this study animated image sequences were created from freely available image quick-looks of orthorectified Landsat scenes for four regions in the central Karakoram mountain range. The animations play automatically in a web-browser and might help to demonstrate glacier flow dynamics for educational purposes. The animations revealed highly complex patterns of glacier flow and surge dynamics over a 15-year time period (1998-2013). In contrast to other regions, surging glaciers in the Karakoram are often small (around 10 km2), steep, debris free, and advance for several years at comparably low annual rates (a few hundred m a-1). The advance periods of individual glaciers are generally out of phase, indicating a limited climatic control on their dynamics. On the other hand, nearly all other glaciers in the region are either stable or slightly advancing, indicating balanced or even positive mass budgets over the past few years to decades.

  9. Intrinsic Negative Feedback Governs Activation Surge in Two-Component Regulatory Systems

    PubMed Central

    Yeo, Won-Sik; Zwir, Igor; Huang, Henry V.; Shin, Dongwoo; Kato, Akinori; Groisman, Eduardo A.

    2013-01-01

    SUMMARY PhoP and PhoQ comprise a two-component system in the bacterium Salmonella enterica. PhoQ is the sensor kinase/phosphatase that modifies the phosphorylation state of the regulator PhoP in response to stimuli. The amount of phosphorylated PhoP surges after activation, then declines to reach a steady-state level. We now recapitulate this surge in vitro by incubating PhoP and PhoQ with ATP and ADP. Mathematical modeling identified PhoQ’s affinity for ADP as the key parameter dictating phosphorylated PhoP levels, as ADP promotes PhoQ’s phosphatase activity toward phosphorylated PhoP. The lid covering the nucleotide-binding pocket of PhoQ governs the kinase to phosphatase switch because a lid mutation that decreased ADP binding compromised PhoQ’s phosphatase activity in vitro and resulted in sustained expression of PhoP-dependent mRNAs in vivo. This feedback mechanism may curtail futile ATP consumption because ADP not only stimulates PhoQ’s phosphatase activity but also inhibits ATP binding necessary for the kinase reaction. PMID:22325356

  10. The effect of changing topography on coastal tides and storm surge: a historical perspective

    NASA Astrophysics Data System (ADS)

    Talke, Stefan; Jay, David; Helaire, Lumas; Familkhalili, Ramin

    2016-11-01

    Over decadal and century time scales, the topography of coastal harbors changes due to natural and anthropogenic factors. These changes alter the mass and momentum balances of incoming waves, producing measureable changes to tides and surge. Here we use recently recovered archival data, historic bathymetric charts, and numerical models to assess changes in multiple estuaries. In the Columbia River estuary, Ems estuary, and Cape Fear Estuary, channel deepening has increased the M2 tide between 10 to 100% since the 19th century, due to both reduced frictional effects and altered resonance. The bathymetric perturbations also affect the propagation of other long-period waves: in Wilmington (NC), the worst-case scenario CAT-5 storm surge is modeled to increase by 50% since 19th century conditions. Similarly, in New York harbor, the 10 year storm-tide level has outpaced sea-level rise by nearly 30 cm since 1850. In the Columbia River, reduced friction has decreased the river slope (reducing water levels), but also led to amplification of both tides and flood waves. Going forward, historical bathymetric change may provide a clue to the future effects of climate change and continued anthropogenic development. National Science Foundation; US Army Corp of Engineers.

  11. Recent changes in surge-associated meteorological events in the Northern Adriatic Sea

    NASA Astrophysics Data System (ADS)

    Pirazzoli, P. A.; Tomasin, A.

    2001-05-01

    The recent increase in the frequency of coastal flooding in Venice (Italy) mainly depends on loss of soil elevation (land subsidence and eustasy) and on man-induced hydrodynamic changes in the lagoon area, but can also be strengthened in the near future by changes in climate. In this paper, after a short review of recent changes in the relative mean and maximal levels of the sea and their causes, the main meteorological factors (atmospheric pressure and winds of bora or sirocco) which produce sea surges in the Gulf of Venice are identified statistically. The recent evolution of these meteorological factors in the Adriatic area shows some favorable trends (the atmospheric pressure is increasing, thus masking provisionally eustatic sea-level rise, and bora is sharply lessening). However, the effects of sirocco, which is increasing in frequency in the central Adriatic, seem to be prevailing. On the whole, the frequency of sea surges greater or equal to 10 to 30 cm is increasing in the North Adriatic and this implies more frequent "moderately high tide levels", which are however liable to flood the lowest parts of the city of Venice.

  12. Breakdown voltage reliability improvement in gas-discharge tube surge protectors employing graphite field emitters

    NASA Astrophysics Data System (ADS)

    Žumer, Marko; Zajec, Bojan; Rozman, Robert; Nemanič, Vincenc

    2012-04-01

    Gas-discharge tube (GDT) surge protectors are known for many decades as passive units used in low-voltage telecom networks for protection of electrical components from transient over-voltages (discharging) such as lightning. Unreliability of the mean turn-on DC breakdown voltage and the run-to-run variability has been overcome successfully in the past by adding, for example, a radioactive source inside the tube. Radioisotopes provide a constant low level of free electrons, which trigger the breakdown. In the last decades, any concept using environmentally harmful compounds is not acceptable anymore and new solutions were searched. In our application, a cold field electron emitter source is used as the trigger for the gas discharge but with no activating compound on the two main electrodes. The patent literature describes in details the implementation of the so-called trigger wires (auxiliary electrodes) made of graphite, placed in between the two main electrodes, but no physical explanation has been given yet. We present experimental results, which show that stable cold field electron emission current in the high vacuum range originating from the nano-structured edge of the graphite layer is well correlated to the stable breakdown voltage of the GDT surge protector filled with a mixture of clean gases.

  13. Balancing Power Absorption and Fatigue Loads in Irregular Waves for an Oscillating Surge Wave Energy Converter

    SciTech Connect

    Tom, Nathan M.; Yu, Yi-Hsiang; Wright, Alan D.; Lawson, Michael

    2016-06-24

    The aim of this paper is to describe how to control the power-to-load ratio of a novel wave energy converter (WEC) in irregular waves. The novel WEC that is being developed at the National Renewable Energy Laboratory combines an oscillating surge wave energy converter (OSWEC) with control surfaces as part of the structure; however, this work only considers one fixed geometric configuration. This work extends the optimal control problem so as to not solely maximize the time-averaged power, but to also consider the power-take-off (PTO) torque and foundation forces that arise because of WEC motion. The objective function of the controller will include competing terms that force the controller to balance power capture with structural loading. Separate penalty weights were placed on the surge-foundation force and PTO torque magnitude, which allows the controller to be tuned to emphasize either power absorption or load shedding. Results of this study found that, with proper selection of penalty weights, gains in time-averaged power would exceed the gains in structural loading while minimizing the reactive power requirement.

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

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

    PubMed

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

    2013-12-01

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

  16. Parallel Computation of Ocean-Atmosphere-Wave Coupled Storm Surge Model

    NASA Astrophysics Data System (ADS)

    Kim, K.; Yamashita, T.

    2003-12-01

    Ocean-atmosphere interactions are very important in the formation and development of tropical storms. These interactions are dominant in exchanging heat, momentum, and moisture fluxes. Heat flux is usually computed using a bulk equation. In this equation air-sea interface supplies heat energy to the atmosphere and to the storm. Dynamical interaction is most often one way in which it is the atmosphere that drives the ocean. The winds transfer momentum to both ocean surface waves and ocean current. The wind wave makes an important role in the exchange of the quantities of motion, heat and a substance between the atmosphere and the ocean. Storm surges can be considered as the phenomena of mean sea-level changes, which are the result of the frictional stresses of strong winds blowing toward the land and causing the set level and the low atmospheric pressure at the centre of the cyclone can additionally raise the sea level. In addition to the rise in water level itself, another wave factor must be considered. A rise of mean sea level due to white-cap wave dissipation should be considered. In bounded bodies of water, such as small seas, wind driven sea level set up is much serious than inverted barometer effects, in which the effects of wind waves on wind-driven current play an important role. It is necessary to develop the coupled system of the full spectral third-generation wind-wave model (WAM or WAVEWATCH III), the meso-scale atmosphere model (MM5) and the coastal ocean model (POM) for simulating these physical interactions. As the component of coupled system is so heavy for personal usage, the parallel computing system should be developed. In this study, first, we developed the coupling system of the atmosphere model, ocean wave model and the coastal ocean model, in the Beowulf System, for the simulation of the storm surge. It was applied to the storm surge simulation caused by Typhoon Bart (T9918) in the Yatsushiro Sea. The atmosphere model and the ocean model have

  17. Observations of the surge-type Black Rapids Glacier, Alaska, during a quiescent period, 1970-92

    USGS Publications Warehouse

    Heinrichs, Thomas A.; Mayo, L.R.; Trabant, D.C.; March, R.S.

    1995-01-01

    This report presents 23 years (1970 to 1992) of observations of Black Rapids Glacier, Alaska. Black Rapids Glacier is a surge-type glacier which most recently surged in 1936-37, and is currently in its quiescent phase. This glacier is of special interest because it is a potential hazard to the trans-Alaska oil pipeline. Ten sites on the glacier were monitored from 1972 to 1987, and three sites were monitored from 1988 to 1992. The measurement program presented here includes observations of surface mass balance, ice velocity, and surface altitude made twice each year. Additional one-time data include observations of ice thickness, previously unreported observations of the 1936-37 surge, establishment of the geodetic control monuments, and a new map of Black Rapids Glacier.

  18. Plasma and ovarian oestradiol and the variability in the LH surge induced in ewes by the ram effect.

    PubMed

    Fabre-Nys, Claude; Chanvallon, Audrey; Debus, Nathalie; François, Dominique; Bouvier, Frédéric; Dupont, Joelle; Lardic, Lionel; Lomet, Didier; Ramé, Christelle; Scaramuzzi, Rex J

    2015-05-01

    The proportion of anoestrous ewes ovulating after exposure to a sexually active ram is variable mainly due to whether an LH surge is induced. The aim of this study was to determine the role of oestradiol (E2) in the ram-induced LH surge. In one study, we measured the plasma concentrations of E2 in ewes of different breeds before and after the 'ram effect' and related these patterns to the presence and latency of the LH surge, while another compared ovarian responses with the 'ram effect' following exposure to rams for 2 or 12 h. In all ewes, the concentration of E2 increased 2-4 h after rams were introduced and remained elevated for 14.5 ± 0.86 h. The quantity of E2 secreted before the LH surge varied among breeds as did the mean concentration of E2. The granulosa cells of IF ewes collected after 12 h exposure to rams secreted more E2 and progesterone and had higher levels of StAR than the 2 h group but in MV ewes there was no differences between these groups for any of these parameters. These results demonstrate that the LH surge induced by the rams is a result of increased E2 secretion associated with increased levels of STAR in granulosa cells and that these responses varied among breeds. The results suggest that the variable occurrence of a LH surge and ovulation may be the result of variable ovarian responses to the 'ram effect' and insensitivity of the hypothalamus to the E2-positive feedback signal.

  19. Analysis of a Storm-induced Surge Anomaly Under Climate Change with Focus on Sea Level Rise

    NASA Astrophysics Data System (ADS)

    Hagen, S. C.; Bilskie, M. V.

    2014-12-01

    The impact of sea level rise (SLR) on hurricane storm surge and wind-waves is a non-linear process (Bilskie et al., 2014). Using a high-resolution physics-based numerical model, we examine shelf wave dynamics in general and a shelf anomaly in particular under global climate change scenarios, which include SLR and potential hurricane intensification. To begin it is noted that Hurricane Dennis (2005) produced local storm surge in Apalachee Bay of six to ten feet, but the National Hurricane Center advisory for the region forecast only four to six feet of storm surge. This forecast was based on the relatively weak wind forcing along the west Florida shelf, but the additional storm-induced surge was caused by a remotely forced shelf wave that propagated along the Florida shelf as a topographic Rossby wave (Morey et al.,2006).These mesoscale processed are studied under climate change scenarios using a state-of-the-art wind-waved hurricane storm surge model (SWAN+ADCIRC) of the northern Gulf of Mexico that encompasses the off-shore regions including the western North Atlantic Ocean, Caribbean Sea, and Gulf of Mexico. The finitie element model penetrates the shoreline along Florida's "Big Bend" region, the Florida panhandle, Alabama, and the Mississippi coast with high resolution that is sufficient to describe the Gulf Intracoastal Waterway, for example. The large domain and fine mesh resolution included in the model permits the description, and non-linear interaction, of the physics associated with wind-generated waves and hurricane storm surge that produce storm-induced anomalies such as the Rossby wave generated during Hurricane Dennis. Examination of various wave statistics such as significant wave height, mean wave period and direction, and wave radiation stress gradients provide insight into future behavior of storm-induced shelf wave dynamics under global climate change scenarios. This study may impact future statistics and probability distributions for analysis of

  20. Objective rapid delineation of areas at risk from block-and-ash pyroclastic flows and surges

    USGS Publications Warehouse

    Widiwijayanti, C.; Voight, B.; Hidayat, D.; Schilling, S.P.

    2009-01-01

    Assessments of pyroclastic flow (PF) hazards are commonly based on mapping of PF and surge deposits and estimations of inundation limits, and/or computer models of varying degrees of sophistication. In volcanic crises a PF hazard map may be sorely needed, but limited time, exposures, or safety aspects may preclude fieldwork, and insufficient time or baseline data may be available for reliable dynamic simulations. We have developed a statistically constrained simulation model for block-and-ash type PFs to estimate potential areas of inundation by adapting methodology from Iverson et al. (Geol Soc America Bull 110:972-984, (1998) for lahars. The predictive equations for block-and-ash PFs are calibrated with data from several volcanoes and given by A = (0.05 to 0.1) V2/3, B = (35 to 40) V2/3, where A is cross-sectional area of inundation, B is planimetric area and V is deposit volume. The proportionality coefficients were obtained from regression analyses and comparison of simulations to mapped deposits. The method embeds the predictive equations in a GIS program coupled with DEM topography, using the LAHARZ program of Schilling (1998). Although the method is objective and reproducible, any PF hazard zone so computed should be considered as an approximate guide only, due to uncertainties on the coefficients applicable to individual PFs, the authenticity of DEM details, and the volume of future collapses. The statistical uncertainty of the predictive equations, which imply a factor of two or more in predicting A or B for a specified V, is superposed on the uncertainty of forecasting V for the next PF to descend a particular valley. Multiple inundation zones, produced by simulations using a selected range of volumes, partly accommodate these uncertainties. The resulting maps show graphically that PF inundation potentials are highest nearest volcano sources and along valley thalwegs, and diminish with distance from source and lateral distance from thalweg. The model does

  1. FLARE FOOTPOINT REGIONS AND A SURGE OBSERVED BY HINODE/EIS, RHESSI, AND SDO/AIA

    SciTech Connect

    Doschek, G. A.; Warren, H. P.; Dennis, B. R.; Reep, J. W.; Caspi, A.

    2015-11-01

    The Extreme-ultraviolet Imaging Spectrometer (EIS) on the Hinode spacecraft observed flare footpoint regions coincident with a surge for an M3.7 flare observed on 2011 September 25 at N12 E33 in active region 11302. The flare was observed in spectral lines of O vi, Fe x, Fe xii, Fe xiv, Fe xv, Fe xvi, Fe xvii, Fe xxiii, and Fe xxiv. The EIS observations were made coincident with hard X-ray bursts observed by RHESSI. Overlays of the RHESSI images on the EIS raster images at different wavelengths show a spatial coincidence of features in the RHESSI images with the EIS upflow and downflow regions, as well as loop-top or near-loop-top regions. A complex array of phenomena were observed, including multiple evaporation regions and the surge, which was also observed by the Solar Dynamics Observatory/Atmospheric Imaging Assembly telescopes. The slit of the EIS spectrometer covered several flare footpoint regions from which evaporative upflows in Fe xxiii and Fe xxiv lines were observed with Doppler speeds greater than 500 km s{sup −1}. For ions such as Fe xv both evaporative outflows (∼200 km s{sup −1}) and downflows (∼30–50 km s{sup −1}) were observed. Nonthermal motions from 120 to 300 km s{sup −1} were measured in flare lines. In the surge, Doppler speeds are found from about 0 to over 250 km s{sup −1} in lines from ions such as Fe xiv. The nonthermal motions could be due to multiple sources slightly Doppler-shifted from each other or turbulence in the evaporating plasma. We estimate the energetics of the hard X-ray burst and obtain a total flare energy in accelerated electrons of ≥7 × 10{sup 28} erg. This is a lower limit because only an upper limit can be determined for the low-energy cutoff to the electron spectrum. We find that detailed modeling of this event would require a multithreaded model owing to its complexity.

  2. Operational forecasting for the Rhine-Meuse Estuary - Modelling and Operating Storm Surge Barriers

    NASA Astrophysics Data System (ADS)

    Bogaard, Tom; van Dam, Theo; Twigt, Daniel; de Goederen, Sacha

    2016-04-01

    Large parts of the Netherlands are very vulnerable to extreme storm surges, due to its low lying, highly populated and economically valuable coastal areas. In this project the focus is on the low-lying Rhine-Meuse estuary in the south-western part of the Netherlands. The area is protected by a complex defence system, including dunes, dikes, large barriers and a retention basin. Hydrodynamics in this complex delta area are influenced by tide, storm surge, discharges of the rivers Rhine and Meuse and the operation of barriers. A forecasting system based on the generic operational platform software Delft-FEWS has been developed in order to produce timely and accurate water level forecasts for the Rhine-Meuse estuary. Barriers as well as their complex closing procedures are included in this operational system. A high resolution 1D hydrodynamic model, forced by Numerical Weather Prediction (NWP) product from the Dutch national weather service (KNMI) and hydrodynamic conditions from the Dutch Water Authority (Rijkswaterstaat), runs every six-hours with a forecast horizon of seven days. The system is operated at Rijkswaterstaat, who is responsible for hydrodynamic forecasting and the operation of the main storm surge barriers of the Netherlands. By running the hydrodynamic model in an automated way the system is able to provide accurate forecasts at all times: during calm weather conditions or when severe storm situations might require closing of the barriers. Especially when storm and peak discharge events coincide, careful operation of the barriers is required. Within the Delft-FEWS platform tools have been developed to test different closing procedures instantly, in case of an event. Expert forecasters will be able to examine effects of multiple closing procedures as well as (partial) failure of the barriers on water levels in the estuary. Apart from forecasting, the system can be used offline to mimic storm events for training purposes. Forecasters at Dutch Water

  3. Flare Footpoint Regions and a Surge Observed by Hindode/EIS, RHESSI, and SDO/AIA

    NASA Astrophysics Data System (ADS)

    Doschek, G. A.; Warren, H. P.; Dennis, B. R.; Reep, J. W.; Caspi, A.

    2015-11-01

    The Extreme-ultraviolet Imaging Spectrometer (EIS) on the Hinode spacecraft observed flare footpoint regions coincident with a surge for an M3.7 flare observed on 2011 September 25 at N12 E33 in active region 11302. The flare was observed in spectral lines of O vi, Fe x, Fe xii, Fe xiv, Fe xv, Fe xvi, Fe xvii, Fe xxiii, and Fe xxiv. The EIS observations were made coincident with hard X-ray bursts observed by RHESSI. Overlays of the RHESSI images on the EIS raster images at different wavelengths show a spatial coincidence of features in the RHESSI images with the EIS upflow and downflow regions, as well as loop-top or near-loop-top regions. A complex array of phenomena were observed, including multiple evaporation regions and the surge, which was also observed by the Solar Dynamics Observatory/Atmospheric Imaging Assembly telescopes. The slit of the EIS spectrometer covered several flare footpoint regions from which evaporative upflows in Fe xxiii and Fe xxiv lines were observed with Doppler speeds greater than 500 km s-1. For ions such as Fe xv both evaporative outflows (˜200 km s-1) and downflows (˜30-50 km s-1) were observed. Nonthermal motions from 120 to 300 km s-1 were measured in flare lines. In the surge, Doppler speeds are found from about 0 to over 250 km s-1 in lines from ions such as Fe xiv. The nonthermal motions could be due to multiple sources slightly Doppler-shifted from each other or turbulence in the evaporating plasma. We estimate the energetics of the hard X-ray burst and obtain a total flare energy in accelerated electrons of ≥7 × 1028 erg. This is a lower limit because only an upper limit can be determined for the low-energy cutoff to the electron spectrum. We find that detailed modeling of this event would require a multithreaded model owing to its complexity.

  4. The Early-Warning System for incoming storm surge and tide in the Republic of Mauritius

    NASA Astrophysics Data System (ADS)

    Bogaard, Tom; de Lima Rego, Joao; Vatvani, Deepak; Virasami, Renganaden; Verlaan, Martin

    2016-04-01

    The Republic of Mauritius (ROM) is a group of islands in the South West of the Indian Ocean, consisting of the main islands of Mauritius, Rodrigues and Agalega and the archipelago of Saint Brandon. The ROM is particularly vulnerable to the adverse effects of climate change, especially in the coastal zone, where a convergence of accelerating sea level rise and increasing intensity of tropical cyclones is expected to result in considerable economic loss, humanitarian stresses, and environmental degradation. Storm surges and swell waves are expected to be aggravated through sea level rise and climate change effects on weather patterns. Adaptation to increased vulnerability requires a re-evaluation of existing preparedness measures. The focus of this project is on more effective preparedness and issuing of alerts developing a fully-automated Early-Warning System for incoming storm surge and tide, together with the Mauritius Meteorological Services and the National Disaster Risk Reduction and Management Centre (NDRRMC), such that coastal communities in Mauritius, Rodrigues and Agalega Islands are able to evacuate timely and safely in case of predicted extreme water levels. The Mauritius Early-Warning System for storm surge and tide was implemented using software from Deltares' Open-Source and free software Community. A set of five depth-averaged Delft3D-FLOW hydrodynamic models are run every six-hours with a forecast horizon of three days, simulating water levels along the coast of the three main islands. Two regional models of horizontal resolution 5km force the three detailed models of 500m resolution; all models are forced at the surface by the 0.25° NOAA/GFS meteorological forecasts. In addition, our Wind-Enhancement Scheme is used to blend detailed cyclone track bulletin's info with the larger-scale Numerical Weather Predictions. Measured data is retrieved near real-time from available Automatic Weather Stations. All these workflows are managed by the operational

  5. Objective rapid delineation of areas at risk from block-and-ash pyroclastic flows and surges

    NASA Astrophysics Data System (ADS)

    Widiwijayanti, C.; Voight, B.; Hidayat, D.; Schilling, S. P.

    2009-08-01

    Assessments of pyroclastic flow (PF) hazards are commonly based on mapping of PF and surge deposits and estimations of inundation limits, and/or computer models of varying degrees of sophistication. In volcanic crises a PF hazard map may be sorely needed, but limited time, exposures, or safety aspects may preclude fieldwork, and insufficient time or baseline data may be available for reliable dynamic simulations. We have developed a statistically constrained simulation model for block-and-ash type PFs to estimate potential areas of inundation by adapting methodology from Iverson et al. (Geol Soc America Bull 110:972-984, 1998) for lahars. The predictive equations for block-and-ash PFs are calibrated with data from several volcanoes and given by A = (0.05 to 0.1) V 2/3, B = (35 to 40) V 2/3, where A is cross-sectional area of inundation, B is planimetric area and V is deposit volume. The proportionality coefficients were obtained from regression analyses and comparison of simulations to mapped deposits. The method embeds the predictive equations in a GIS program coupled with DEM topography, using the LAHARZ program of Schilling (1998). Although the method is objective and reproducible, any PF hazard zone so computed should be considered as an approximate guide only, due to uncertainties on the coefficients applicable to individual PFs, the authenticity of DEM details, and the volume of future collapses. The statistical uncertainty of the predictive equations, which imply a factor of two or more in predicting A or B for a specified V, is superposed on the uncertainty of forecasting V for the next PF to descend a particular valley. Multiple inundation zones, produced by simulations using a selected range of volumes, partly accommodate these uncertainties. The resulting maps show graphically that PF inundation potentials are highest nearest volcano sources and along valley thalwegs, and diminish with distance from source and lateral distance from thalweg. The model

  6. Deriving spatial and temporal patterns of coastal marsh aggradation from hurricane storm surge marker beds

    NASA Astrophysics Data System (ADS)

    Hodge, Joshua; Williams, Harry

    2016-12-01

    This study uses storm surge sediment beds deposited by Hurricanes Audrey (1957), Carla (1961), Rita (2005) and Ike (2008) to investigate spatial and temporal changes in marsh sedimentation on the McFaddin National Wildlife Refuge in Southeastern Texas. Fourteen sediment cores were collected along a transect extending 1230 m inland from the Gulf coast. Storm-surge-deposited sediment beds were identified by texture, organic content, carbonate content, the presence of marine microfossils and 137Cs dating. The hurricane-derived sediment beds facilitate assessment of changes in marsh sedimentation from nearshore to inland locations and over decadal to annual timescales. Spatial variation along the transect reflects varying contributions from three prevailing sediment sources: flooding, overwash and organic sedimentation from marsh plants. Over about the last decade, hurricane overwash has been the predominant sediment source for nearshore locations because of large sediment inputs from Hurricanes Rita and Ike. Farther inland, hurricane inputs diminish and sedimentation is dominated by deposition from flood waters and a larger organic component. Temporal variations in sedimentation reflect hurricane activity, changes in marsh surface elevation and degree of compaction of marsh sediments, which is time-dependent. There was little to no marsh sedimentation in the period 2008-2014, firstly because no hurricanes impacted the study area and secondly because overwash sedimentation prior to 2008 had increased nearshore marsh surface elevations by up to 0.68 m, reducing subsequent inputs from flooding. Marsh sedimentation rates were relatively high in the period 2005-2008, averaging 2.13 cm/year and possibly reflecting sediment contributions from Hurricanes Humberto and Gustav. However, these marsh sediments are highly organic and largely uncompacted. Older, deeper marsh deposits formed between 1961 and 2005 are less organic-rich, more compacted and have an average annual

  7. Solar pacing of storm surges, coastal flooding and agricultural losses in the Central Mediterranean.

    PubMed

    Kaniewski, David; Marriner, Nick; Morhange, Christophe; Faivre, Sanja; Otto, Thierry; Van Campo, Elise

    2016-04-29

    Storm surges, leading to catastrophic coastal flooding, are amongst the most feared natural hazards due to the high population densities and economic importance of littoral areas. Using the Central Mediterranean Sea as a model system, we provide strong evidence for enhanced periods of storminess leading to coastal flooding during the last 4500 years. We show that long-term correlations can be drawn between storminess and solar activity, acting on cycles of around 2200-yr and 230-yr. We also find that phases of increased storms and coastal flooding have impacted upon mid- to late Holocene agricultural activity on the Adriatic coast. Based on the general trend observed during the second half of the 20(th) century, climate models are predicting a weakening of Mediterranean storminess. By contrast, our new data suggest that a decrease in solar activity will increase and intensify the risk of frequent flooding in coastal areas.

  8. Solar pacing of storm surges, coastal flooding and agricultural losses in the Central Mediterranean

    PubMed Central

    Kaniewski, David; Marriner, Nick; Morhange, Christophe; Faivre, Sanja; Otto, Thierry; Van Campo, Elise

    2016-01-01

    Storm surges, leading to catastrophic coastal flooding, are amongst the most feared natural hazards due to the high population densities and economic importance of littoral areas. Using the Central Mediterranean Sea as a model system, we provide strong evidence for enhanced periods of storminess leading to coastal flooding during the last 4500 years. We show that long-term correlations can be drawn between storminess and solar activity, acting on cycles of around 2200-yr and 230-yr. We also find that phases of increased storms and coastal flooding have impacted upon mid- to late Holocene agricultural activity on the Adriatic coast. Based on the general trend observed during the second half of the 20th century, climate models are predicting a weakening of Mediterranean storminess. By contrast, our new data suggest that a decrease in solar activity will increase and intensify the risk of frequent flooding in coastal areas. PMID:27126207

  9. Debris flows: geologic process and hazard; illustrated by a surge sequence at Jiangjia Ravine, Yunnan, China

    USGS Publications Warehouse

    Scott, Kevin M.; Yuyi, Wang

    2004-01-01

    Debris flows are slurries of sediment and water that are both an important geologic process and a major hazard. They present large risks to those living in mountainous areas, as well as downstream from volcanoes in the case of the flows known as lahars that may travel 100200 kilometers (62-124 miles). The accompanying video records a series of debris flow surges at Jiangjia Ravine, in Yunnan Province in southern China. This rugged and remote site is famous for the annual occurrence of debris flows triggered each summer by monsoonal rains. The video illustrates the unique characteristics of debris flows, how they behave, and why they cause large losses of life and property in China and many other parts of the world. This report is a summary for those wishing more information than is presented in the video, and for the specialist we include dynamical data on the flows and textural data on their deposits.

  10. Leaf hydraulic evolution led a surge in leaf photosynthetic capacity during early angiosperm diversification.

    PubMed

    Brodribb, Tim J; Feild, Taylor S

    2010-02-01

    Angiosperm evolution transformed global ecology, and much of this impact derives from the unrivalled vegetative productivity of dominant angiosperm clades. However, the origins of high photosynthetic capacity in angiosperms remain unknown. In this study, we describe the steep trajectory of leaf vein density (D(v)) evolution in angiosperms, and predict that this leaf plumbing innovation enabled a major shift in the capacity of leaves to assimilate CO(2). Reconstructing leaf vein evolution from an examination of 504 angiosperm species we found a rapid three- to fourfold increase in D(v) occurred during the early evolution of angiosperms. We demonstrate how this major shift in leaf vein architecture potentially allowed the maximum photosynthetic capacity in angiosperms to rise above competing groups 140-100 Ma. Our data suggest that early terrestrial angiosperms produced leaves with low photosynthetic rates, but that subsequent angiosperm success is linked to a surge in photosynthetic capacity during their early diversification.

  11. Solar pacing of storm surges, coastal flooding and agricultural losses in the Central Mediterranean

    NASA Astrophysics Data System (ADS)

    Kaniewski, David; Marriner, Nick; Morhange, Christophe; Faivre, Sanja; Otto, Thierry; van Campo, Elise

    2016-04-01

    Storm surges, leading to catastrophic coastal flooding, are amongst the most feared natural hazards due to the high population densities and economic importance of littoral areas. Using the Central Mediterranean Sea as a model system, we provide strong evidence for enhanced periods of storminess leading to coastal flooding during the last 4500 years. We show that long-term correlations can be drawn between storminess and solar activity, acting on cycles of around 2200-yr and 230-yr. We also find that phases of increased storms and coastal flooding have impacted upon mid- to late Holocene agricultural activity on the Adriatic coast. Based on the general trend observed during the second half of the 20th century, climate models are predicting a weakening of Mediterranean storminess. By contrast, our new data suggest that a decrease in solar activity will increase and intensify the risk of frequent flooding in coastal areas.

  12. Design Of An Electrical Flywheel For Surge Power Applications In Mobile Robots

    NASA Astrophysics Data System (ADS)

    Wright, David D.

    1987-01-01

    An energy boost system based on a flywheel has been designed to supply the surge power needs of mobile robots for operating equipment like transmitters, drills, manipulator arms, mobility augmenters, and etc. This flywheel increases the average power available from a battery, fuel cell, generator, RPG or solar array by one or more orders of magnitude for short periods. Flywheels can be charged and discharged for thousands of battery lifetimes. Flywheels can deliver more than ten times the power per unit weight of batteries. The electromechanical details of a reliable, energy efficient and (relatively) low cost flywheel are described. This flywheel is the combination of a highly efficient brushless motor and a laminated steel rotor operating in an hermetically sealed container with only electrical input and output. This design approach overcomes the inefficiencies generally associated with mechanically geared devices. Electrical round trip efficiency is 94% under optimum operating conditions.

  13. Low-impedance cable for parallel-connected surge protective devices

    SciTech Connect

    Bulson, J.M.

    1995-10-01

    A coaxial low-impedance cable is described for surge protective device (SPD) wiring applications. The cable is designed to replace conventional wiring when parallel connecting any SPD which depends on the applied transient voltage to function. The cable is designed to minimize the transmission loss (voltage drop) of lightning and switching transients from the point of protection to the SPD components. This is accomplished primarily by minimizing the cable inductance through a reduced coaxial aspect ratio (major to minor diameter). The resultant cable has a very low characteristic impedance (2--15 {Omega}). The suppression performance of an SPD installed with 10 AWG coaxial cables provides an improvement of a factor of 2--4 over that using conventional wiring. The cable design details are discussed along with sure suppression performance.

  14. Reducing wait times through operations research: optimizing the use of surge capacity.

    PubMed

    Patrick, Jonathan; Puterman, Martin L

    2008-01-01

    Widespread public demand for improved access, political pressure for shorter wait times, a stretched workforce, an aging population and overutilized equipment and facilities challenge healthcare leaders to adopt new management approaches. This paper highlights the significant benefits that can be achieved by applying operations research (OR) methods to healthcare management. It shows how queuing theory provides managers with insights into the causes for excessive wait times and the relationship between wait times and capacity. It provides a case study of the use of several OR methods, including Markov decision processes, linear programming and simulation, to optimize the scheduling of patients with multiple priorities. The study shows that by applying this approach, wait time targets can be attained with the judicious use of surge capacity in the form of overtime. It concludes with some policy insights.

  15. Reducing Wait Times through Operations Research: Optimizing the Use of Surge Capacity.

    PubMed

    Patrick, Jonathan; Puterman, Martin L

    2008-02-01

    Widespread public demand for improved access, political pressure for shorter wait times, a stretched workforce, an aging population and overutilized equipment and facilities challenge healthcare leaders to adopt new management approaches. This paper highlights the significant benefits that can be achieved by applying operations research (OR) methods to healthcare management. It shows how queuing theory provides managers with insights into the causes for excessive wait times and the relationship between wait times and capacity. It provides a case study of the use of several OR methods, including Markov decision processes, linear programming and simulation, to optimize the scheduling of patients with multiple priorities. The study shows that by applying this approach, wait time targets can be attained with the judicious use of surge capacity in the form of overtime. It concludes with some policy insights.

  16. Silencing of PMT expression caused a surge of anatabine accumulation in tobacco.

    PubMed

    Wang, Peng; Zeng, Jia; Liang, Zhifeng; Miao, Zhiqi; Sun, Xiaofen; Tang, Kexuan

    2009-11-01

    Drastic increase of anatabine levels was observed in tobacco plants with markedly reduced nicotine concentrations through RNA silencing approaches. By down-regulation of PMT through three kinds of RNA silencing approaches, the nicotine levels decreased accordingly. In lines with slight and moderate reduction of nicotine levels, no anticipated negative linear correlation was found between anatabine and nicotine content. In lines with nicotine levels lower than 2.7 mg/g, drastic elevation of anatabine levels was found. Transcriptional levels of QPRT were unaffected in tobacco lines with surged anatabine levels. This report of an intriguing mutual relationship of nicotine and anatabine sheds new light on mechanisms between metabolic regulations in plants, and reconfirms complexity of metabolic networks.

  17. Developing the First Gapless ZnO Surge Arrester in the World

    NASA Astrophysics Data System (ADS)

    Hayashi, Masao; Kobayashi, Misao

    Metal Oxide Surge Arrester (MOSA) technology was first developed in Japan and improved. Original discovery was made by Matsushita Electric Industry Co., Ltd by a finding of some diode phenomenon. Meidensha Corporation applied it to high voltage grid system in Japan in 1975 as a reliable lightning protection device. Japanese MOSA manufactures played a leading role in world MOSA innovations and developments. The BIL has been standardized based on arrester protective characteristics. Due to MOSA, the product shift to MOSA occurred from the gapped type arresters (GTA) 35 years ago as GTA had many gap-related problems. The MOSA became a complete IEC standard (IEC60099-4-1991) taking 20 years from starting development. The MOSA now has a solid footprint in the world lightning protection space.

  18. A simple method of observation impact analysis for operational storm surge forecasting systems

    NASA Astrophysics Data System (ADS)

    Sumihar, Julius; Verlaan, Martin

    2016-04-01

    In this work, a simple method is developed for analyzing the impact of assimilating observations in improving forecast accuracy of a model. The method simply makes use of observation time series and the corresponding model output that are generated without data assimilation. These two time series are usually available in an operational database. The method is therefore easy to implement. Moreover, it can be used before actually implementing any data assimilation to the forecasting system. In this respect, it can be used as a tool for designing a data assimilation system, namely for searching for an optimal observing network. The method can also be used as a diagnostic tool, for example, for evaluating an existing operational data assimilation system to check if all observations are contributing positively to the forecast accuracy. The method has been validated with some twin experiments using a simple one-dimensional advection model as well as with an operational storm surge forecasting system based on the Dutch Continental Shelf model version 5 (DCSMv5). It has been applied for evaluating the impact of observations in the operational data assimilation system with DCSMv5 and for designing a data assimilation system for the new model DCSMv6. References: Verlaan, M. and J. Sumihar (2016), Observation impact analysis methods for storm surge forecasting systems, Ocean Dynamics, ODYN-D-15-00061R1 (in press) Zijl, F., J. Sumihar, and M. Verlaan (2015), Application of data assimilation for improved operational water level forecasting of the northwest European shelf and North Sea, Ocean Dynamics, 65, Issue 12, pp 1699-1716.

  19. Simulation of Storm Surge by a Depth-integrated Non-hydrostatic Nested-gird Model

    NASA Astrophysics Data System (ADS)

    Tsai, Yu-Lin; Wu, Tso-Ren; Terng, Chuen-Teyr; Cheung, Mei-Hui

    2015-04-01

    This paper presents COMCOT-SS (COrnell Multi-grid Coupled of Tsunami Model - Storm Surge) operational model, a depth integrated non-hydrostatic storm surge model developed for the Central Weather Bureau (CWB) in Taiwan. This model is based on the widely-validated COMCOT tsunami model. However, the governing equations were modified to be a depth-integrated vertical momentum equation, and the nonlinear shallow water equations including extra terms, such as the non-hydrostatic pressure, weather forcing, and tidal terms. The non-hydrostatic term enables the model to simulate relatively steep waves in the near-shore region. The conventional features in COMCOT, such as the nested-grid system, spherical and Cartesian coordinate systems, and the moving boundary scheme for inundation prediction were preserved. In this study, we carefully validated the model with analytic solutions for wind shear stress and pressure gradient terms. TWRF (Typhoon Weather Research and Forecasting) model was coupled for providing the meteorological forces generated by typhoons. Besides, parametric typhoon models such as Holland model (1980) and CWB model were also coupled with COMCOT-SS in which the drag coefficient was advised by Large and Pond (1981) and Powell (2003). Astronomical tide provided by the TPXO global tidal model was imported from the domain boundaries. As for the model performance, COMCOT-SS spends less than 30 minutes to finish a 48-hrs forecasting with a large computational domain which covers Taiwan Strait and most parts of Western Pacific Ocean and South China Sea and satisfies the requirement of early warning. In this paper, we also presented the results of nine typical typhoon routes defined by CWB in Taiwan for the model verification. The simulation results accompanied with the non-hydrostatic effect presented good agreement with observation data. Detailed results and discussion will be presented in EGU, 2015.

  20. Cold Exposure Can Induce an Exaggerated Early-Morning Blood Pressure Surge in Young Prehypertensives.

    PubMed

    Hong, Cian-Hui; Kuo, Terry B J; Huang, Bo-Chi; Lin, Yu-Cheng; Kuo, Kuan-Liang; Chern, Chang-Ming; Yang, Cheryl C H

    2016-01-01

    Prehypertension is related to a higher risk of cardiovascular events than normotension. Our previous study reported that cold exposure elevates the amplitude of the morning blood pressure surge (MBPS) and is associated with a sympathetic increase during the final sleep transition, which might be critical for sleep-related cardiovascular events in normotensives. However, few studies have explored the effects of cold exposure on autonomic function during sleep transitions and changes of autonomic function among prehypertensives. Therefore, we conducted an experiment for testing the effects of cold exposure on changes of autonomic function during sleep and the MBPS among young prehypertensives are more exaggerate than among young normotensives. The study groups consisted of 12 normotensive and 12 prehypertensive male adults with mean ages of 23.67 ± 0.70 and 25.25 ± 0.76 years, respectively. The subjects underwent cold (16°C) and warm (23°C) conditions randomly. The room temperature was maintained at either 23°C or 16°C by central air conditioning and recorded by a heat-sensitive sensor placed on the forehead and extended into the air. BP was measured every 30 minutes by using an autonomic BP monitor. Electroencephalograms, electrooculograms, electromyograms, electrocardiograms, and near body temperature were recorded by miniature polysomnography. Under cold exposure, a significantly higher amplitude of MBPS than under the warm condition among normotensives; however, this change was more exaggerated in prehypertensives. Furthermore, there was a significant decrease in parasympathetic-related RR and HF during the final sleep transition and a higher early-morning surge in BP and in LF% among prehypertensives, but no such change was found in normotensives. Our study supports that cold exposure might increase the risk of sleep-related cardiovascular events in prehypertensives.

  1. Pharmacological blockade of gap junctions induces repetitive surging of extracellular potassium within the locust CNS.

    PubMed

    Spong, Kristin E; Robertson, R Meldrum

    2013-10-01

    The maintenance of cellular ion homeostasis is crucial for optimal neural function and thus it is of great importance to understand its regulation. Glial cells are extensively coupled by gap junctions forming a network that is suggested to serve as a spatial buffer for potassium (K(+)) ions. We have investigated the role of glial spatial buffering in the regulation of extracellular K(+) concentration ([K(+)]o) within the locust metathoracic ganglion by pharmacologically inhibiting gap junctions. Using K(+)-sensitive microelectrodes, we measured [K(+)]o near the ventilatory neuropile while simultaneously recording the ventilatory rhythm as a model of neural circuit function. We found that blockade of gap junctions with either carbenoxolone (CBX), 18β-glycyrrhetinic acid (18β-GA) or meclofenamic acid (MFA) reliably induced repetitive [K(+)]o surges and caused a progressive impairment in the ability to maintain baseline [K(+)]o levels throughout the treatment period. We also show that a low dose of CBX that did not induce surging activity increased the vulnerability of locust neural tissue to spreading depression (SD) induced by Na(+)/K(+)-ATPase inhibition with ouabain. CBX pre-treatment increased the number of SD events induced by ouabain and hindered the recovery of [K(+)]o back to baseline levels between events. Our results suggest that glial spatial buffering through gap junctions plays an essential role in the regulation of [K(+)]o under normal conditions and also contributes to a component of [K(+)]o clearance following physiologically elevated levels of [K(+)]o.

  2. Acute estrogen surge enhances inflammatory nociception without altering spinal Fos expression.

    PubMed

    Ralya, Andrew; McCarson, Kenneth E

    2014-07-11

    Chronic pain is a major neurological disorder that can manifest differently between genders or sexes. The complex actions of sex hormones may underlie these differences; previous studies have suggested that elevated estrogen levels can enhance pain perception. The purpose of this study was to investigate the hypothesis that acute, activational effects of estradiol (E2) increase persistent inflammatory nociception, and anatomically where this modulation occurs. Spinal expression of Fos is widely used as a marker of nociceptive activation. This study used formalin-evoked nociception in ovariectomized (OVX) adult female rats and measured late-phase hindlimb flinching and Fos expression in the spinal cord, and their modification by acute estrogen supplementation similar to a proestrus surge. Six days after ovariectomy, female rats were injected subcutaneously (s.c.) with 10μg/kg E2 or vehicle. Twenty-four hours later, 50μL of 1.25% or 100μL of 5% formalin was injected into the right hindpaw; hindlimb flinches were counted, and spinal cords removed 2h after formalin injection. The numbers of Fos-expressing neurons in sections of the lumbar spinal cord were analyzed using immunohistochemistry. Formalin-induced inflammation produced a dose-dependent increase in late-phase hindlimb flinching, and E2 pretreatment increased flinching following 5%, but not 1.25% formalin injection. Despite the modification of behavior by E2, the number of spinal Fos-positive neurons was not altered by E2 pretreatment. These findings demonstrate that an acute proestrus-like surge in serum estrogen can produce a stimulus-intensity-dependent increase in inflammation-evoked nociceptive behavior. However, the lack of effect on spinal Fos expression suggests that this enhancement of nociceptive signaling by estrogen is independent of changes in peripheral activation of, expression of the immediate early gene Fos by, or signal throughput of spinal nociceptive neurons.

  3. Prognostic Significance of the Morning Blood Pressure Surge in Clinical Practice: A Systematic Review

    PubMed Central

    Hodgkinson, James; Riley, Richard; Martin, Una; Bayliss, Susan; McManus, Richard J.

    2015-01-01

    BACKGROUND An exaggerated morning blood pressure surge (MBPS) may be associated with stroke and other cardiovascular events, but the threshold at which an MBPS becomes pathological is unclear. This study aimed to systematically review the existing literature and establish the most appropriate definition of pathological MBPS. METHODS A MEDLINE search strategy was adapted for a range of literature databases to identify all prospective studies relating an exaggerated MBPS to cardiovascular endpoints. Hazard ratios (HRs) were extracted and synthesized using random-effects meta-analysis. RESULTS The search strategy identified 2,964 unique articles, of which 17 were eligible for the study. Seven different definitions of MBPS were identified; the most common was a prewaking surge (mean blood pressure for 2 hours after wake-up minus mean blood pressure for 2 hours before wake-up; n = 6 studies). Summary meta-analysis gave no clear evidence that prewaking MBPS (defined by a predetermined threshold: >25–55mm Hg) was associated with all cardiovascular events (n = 2 studies; HR = 0.94, 95% confidence interval (CI) = 0.39–2.28) or stroke (n = 2 studies; HR = 1.26, 95% CI = 0.92–1.71). However, using a continuous scale, which has more power to detect an association, there was evidence that a 10 mm Hg increase in MBPS was related to an increased risk of stroke (n = 3 studies; HR = 1.11, 95% CI = 1.03–1.20). CONCLUSIONS These findings suggest that when measured and analyzed as a continuous variable, increasing levels of MBPS may be associated with increased risk of stroke. Large, protocol-driven individual patient data analyses are needed to accurately define this relationship further. PMID:25315474

  4. State feedback control of surge oscillations of two-point mooring system

    NASA Astrophysics Data System (ADS)

    Mitra, R. K.; Banik, A. K.; Chatterjee, S.

    2017-01-01

    Stability analysis of surge oscillations of two-point mooring system under state feedback control with time-delay is investigated. The two-point mooring system is harmonically excited and essentially represents a strongly nonlinear Duffing oscillator. In this paper, a frequency domain based method viz. incremental harmonic balance method along with arc-length continuation technique (IHBC) is first employed to identify the primary and higher order subharmonic responses which may be present in such system. The IHBC is then reformulated in a manner to treat two-point mooring system under state feedback control with time-delay and is applied to obtain control of responses in an efficient and systematic way. The stability of uncontrolled responses for primary and higher order subharmonic oscillations is obtained by Floquet's theory using Hsu' scheme; whereas the stability of controlled responses is obtained by applying semi-discretization method for delay differential equation. The study focussed on the controlling primary, higher order subharmonics and chaotic responses by considering appropriate feedback gains and delay by way of (i) appreciable reduction of primary, subharmonic responses, (ii) exclusion of all higher order subharmonics 2T, 3T, 5T and 9T (1/n subharmonics or period-n solutions), and (iii) reduction of the extent of domain of all instability phenomena represented by various type of bifurcation of solutions, jump phenomena, chaotic responses etc. In the study, negative velocity feedback is observed to be much effective than state feedback for better controlling of surge oscillation of two-point mooring system. Also, the effect of larger gain values is investigated by an extensive parametric study for vibration control with different delay values.

  5. Comparing hurricane and extratropical storm surge for the Mid-Atlantic and Northeast Coast of the United States for 1979-2013

    NASA Astrophysics Data System (ADS)

    Booth, J. F.; Rieder, H. E.; Kushnir, Y.

    2016-09-01

    This letter examines the magnitude, spatial footprint, and paths of hurricanes and extratropical cyclones (ETCs) that caused strong surge along the east coast of the US between 1979 and 2013. Lagrangian cyclone track information, for hurricanes and ETCs, is used to associate surge events with individual storms. First, hurricane influence is examined using ranked surged events per site. The fraction of hurricanes among storms associated with surge decreases from 20%-60% for the top 10 events to 10%-30% for the top 50 events, and a clear latitudinal gradient of hurricane influence emerges for larger sets of events. Secondly, surges on larger spatial domains are examined by focusing on storms that cause exceedance of the probabilistic 1-year surge return level at multiple stations. Results show that if the strongest events in terms of surge amplitude and spatial extent are considered, then hurricanes are most likely to create the hazards. However, when slightly less strong events that still impact multiple areas during the storm life cycle are considered, the relative importance of hurricanes shrinks as that of ETCs grows. Furthermore we find distinct paths for ETCs causing multi-site surge at individual segments of the US east coast.

  6. The benefits of designing a stratification system for New York City pediatric intensive care units for use in regional surge capacity planning and management.

    PubMed

    Campbell, Christiana

    2010-08-01

    Accurate assessment of New York City (NYC) pediatric intensive care unit (PICU) resources and the ability to surge them during a disaster has been recognized as an important citywide emergency preparedness activity. However, while NYC hospitals with PICUs may be expected to surge in a disaster, few of them have detailed surge capacity plans. This will likely make it difficult for them to realize their full surge capacity both on individual and regional levels. If the pediatric resources that each NYC PICU hospital has can be identified prior to a disaster, this information can be used to both determine appropriate surge capacity goals for each PICU hospital and the additional resources needed to reach those goals. City agencies can then focus citywide planning efforts on making these resources available and more easily anticipate what a hospital will need during a disaster. Communication of this hospital information both prior to and during a surge situation will be aided by a stratification system familiar to both city planners and hospitals. The goal of this project was to design a NYC PICU surge stratification system that would aid physicians, hospitals and city agencies in regional surge capacity planning for critical pediatric patients. This goal was demonstrated through two objectives. The first identified major factors to consider when designing a stratification system. The second devised a preliminary system of PICU stratification based on clinical criteria and resources.

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

    PubMed

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

    2013-06-01

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

  8. Storm Surges in New York During Hurricane Sandy in 2012: A Verification of the Wind-Stress Tide Relation

    NASA Astrophysics Data System (ADS)

    Hsu, S. A.

    2013-09-01

    In October 2012 Hurricane Sandy devastated New York City and its vicinity caused mainly by the storm surge, which is the water height above normal astronomical tide level. The meteorological conditions were as follows: minimum central pressure, 962 hPa, highest sustained wind speed 27.1 m s and maximum gust 37.8 m s. The peak storm surge was at 3.9 m and the peak storm tide at 4.4 m (which is referenced above mean lower low water). The wind-stress tide relation shows that , where is the storm surge, is the wind speed and is the coefficient. It is found that with in units of m, and in m s, with ( is the correlation coefficient) indicating that 91 % of the total variation of the storm surge can be explained by variations in the wind stress, which is proportional to . Similar results were obtained during Hurricane Irene in 2011, which also affected the New York area. Therefore, this simple wind stress-tide relation should be useful in coastal engineering, urban planning, and emergency management.

  9. An investigation of ensemble-based assimilation of satellite altimetry and tide gauge data in storm surge prediction

    NASA Astrophysics Data System (ADS)

    Etala, Paula; Saraceno, Martín; Echevarría, Pablo

    2015-03-01

    Cyclogenesis and long-fetched winds along the southeastern coast of South America may lead to floods in populated areas, as the Buenos Aires Province, with important economic and social impacts. A numerical model (SMARA) has already been implemented in the region to forecast storm surges. The propagation time of the surge in such extensive and shallow area allows the detection of anomalies based on observations from several hours up to the order of a day prior to the event. Here, we investigate the impact and potential benefit of storm surge level data assimilation into the SMARA model, with the objective of improving the forecast. In the experiments, the surface wind stress from an ensemble prediction system drives a storm surge model ensemble, based on the operational 2-D depth-averaged SMARA model. A 4-D Local Ensemble Transform Kalman Filter (4D-LETKF) initializes the ensemble in a 6-h cycle, assimilating the very few tide gauge observations available along the northern coast and satellite altimeter data. The sparse coverage of the altimeters is a challenge to data assimilation; however, the 4D-LETKF evolving covariance of the ensemble perturbations provides realistic cross-track analysis increments. Improvements on the forecast ensemble mean show the potential of an effective use of the sparse satellite altimeter and tidal gauges observations in the data assimilation prototype. Furthermore, the effects of the localization scale and of the observational errors of coastal altimetry and tidal gauges in the data assimilation approach are assessed.

  10. 40 CFR Table 2 to Subpart V of... - Surge Control Vessels and Bottoms Receivers at New Sources

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Receivers at New Sources 2 Table 2 to Subpart V of Part 61 Protection of Environment ENVIRONMENTAL... POLLUTANTS National Emission Standard for Equipment Leaks (Fugitive Emission Sources) Pt. 61, Subpt. V, Table 2 Table 2 to Subpart V of Part 61—Surge Control Vessels and Bottoms Receivers at New Sources...

  11. 40 CFR Table 1 to Subpart V of... - Surge Control Vessels and Bottoms Receivers at Existing Sources

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Receivers at Existing Sources 1 Table 1 to Subpart V of Part 61 Protection of Environment ENVIRONMENTAL... POLLUTANTS National Emission Standard for Equipment Leaks (Fugitive Emission Sources) Pt. 61, Subpt. V, Table 1 Table 1 to Subpart V of Part 61—Surge Control Vessels and Bottoms Receivers at Existing...

  12. The ExploreSurge Trail Guide and Hiking Workshop: discipline-specific education for public health nurses.

    PubMed

    Stanley, Sharon A R; Polivka, Barbara J; Gordon, Deanna; Taulbee, Kelly; Kieffer, Gloria; McCorkle, Sheryl M

    2008-01-01

    Generic preparedness education and training for the public health workforce has increased in availability over the past 5 years. Registered Nurses also have more opportunities available for participation in emergency and disaster preparedness curricula. Discipline- and specialty-specific training and education for public health nurses (PHNs) incorporating their population-based practice, however, remains a largely unexplored area that is not accessible except for sporadic local venues. The Public Health Nursing Surge Curriculum provides 50 hr of nursing continuing education and activity-based aggregate focused learning experiences that are completed within a 12-month period, including an in-classroom seminar. The Public Health Nursing Surge Curriculum was developed on a foundation of 25 competencies linking PHNs and their population-based practice to surge capability. The curriculum was built in partnership with statewide public health directors of nursing over a 12-month period and is evaluated by a 3-level process to include self-rated confidence in performance. The curriculum's use of a blended learning methodology enables staff-level PHNs to master individual competencies toward surge capability within the public health response system.

  13. 40 CFR Table 1 to Subpart V of... - Surge Control Vessels and Bottoms Receivers at Existing Sources

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Receivers at Existing Sources 1 Table 1 to Subpart V of Part 61 Protection of Environment ENVIRONMENTAL... POLLUTANTS National Emission Standard for Equipment Leaks (Fugitive Emission Sources) Pt. 61, Subpt. V, Table 1 Table 1 to Subpart V of Part 61—Surge Control Vessels and Bottoms Receivers at Existing...

  14. 40 CFR Table 1 to Subpart V of... - Surge Control Vessels and Bottoms Receivers at Existing Sources

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Receivers at Existing Sources 1 Table 1 to Subpart V of Part 61 Protection of Environment ENVIRONMENTAL... POLLUTANTS National Emission Standard for Equipment Leaks (Fugitive Emission Sources) Pt. 61, Subpt. V, Table 1 Table 1 to Subpart V of Part 61—