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Sample records for hurricane inner-core structure

  1. Inner core structure behind the PKP core phase triplication

    NARCIS (Netherlands)

    Blom, Nienke A.; Deuss, Arwen; Paulssen, Hanneke; Waszek, Lauren

    2015-01-01

    The structure of the Earth's inner core is not well known between depths of ∼100–200 km beneath the inner core boundary. This is a result of the PKP core phase triplication and the existence of strong precursors to PKP phases, which hinder the measurement of inner core compressional PKIKP waves at e

  2. Inner core structure behind the PKP core phase triplication

    NARCIS (Netherlands)

    Blom, Nienke A.; Deuss, Arwen; Paulssen, Hanneke; Waszek, Lauren

    The structure of the Earth's inner core is not well known between depths of ∼100–200 km beneath the inner core boundary. This is a result of the PKP core phase triplication and the existence of strong precursors to PKP phases, which hinder the measurement of inner core compressional PKIKP waves at

  3. Seismic Structures in the Earth's Inner Core Below Southeastern Asia

    Science.gov (United States)

    Krasnoshchekov, Dmitry; Kaazik, Petr; Kozlovskaya, Elena; Ovtchinnikov, Vladimir

    2016-05-01

    Documenting seismic heterogeneities in the Earth's inner core (IC) is important in terms of getting an insight into its history and dynamics. A valuable means for studying properties and spatial structure of such heterogeneities is provided by measurements of body waves refracted in the vicinity of the inner core boundary (ICB). Here, we investigate eastern hemisphere of the solid core by means of PKPBC-PKPDF differential travel times that sample depths from 140 to 360 km below its boundary. We study 292 polar and 133 equatorial residuals measured over the traces that probe roughly the same volume of the IC in both planes. Equatorial residuals show slight spatial variations in the sampled IC volume mostly below the level of 0.5 %, whereas polar residuals are up to three times as big, direction dependent and can exhibit higher local variations. The measurements reveal fast changes in seismic velocity within a restricted volume of the IC. We interpret the observations in terms of anisotropy and check against several anisotropy models few of which have been found capable of fitting the residuals scatter. We particularly quantify the model where a dipping discontinuity separates fully isotropic roof of the IC from its anisotropic body, whereas the depth of isotropy-anisotropy transition increases in southeast direction from 190 km below Southeastern Asia (off the coast of China) to 350 km beneath Australia. Another acceptable model cast in terms of localized anisotropic heterogeneities is valid if 33 largest polar measurements over the rays sampling a small volume below Southeastern Asia and the rest of polar data are treated separately. This model envisages almost isotropic eastern hemisphere of the IC at least down to the depth of 360 km below the ICB and constrains the anisotropic volume only to the ranges of North latitudes from 18° to 23°, East longitudes from 125° to 135° and depths exceeding 170 km. The anisotropy strength in either model is about 2

  4. High-resolution probing of inner core structure with seismic interferometry

    KAUST Repository

    Huang, Hsin-Hua

    2015-12-23

    © 2015. American Geophysical Union. All Rights Reserved. Increasing complexity of Earth\\'s inner core has been revealed in recent decades as the global distribution of seismic stations has improved. The uneven distribution of earthquakes, however, still causes a biased geographical sampling of the inner core. Recent developments in seismic interferometry, which allow for the retrieval of core-sensitive body waves propagating between two receivers, can significantly improve ray path coverage of the inner core. In this study, we apply such earthquake coda interferometry to 1846 USArray stations deployed across the U.S. from 2004 through 2013. Clear inner core phases PKIKP2 and PKIIKP2 are observed across the entire array. Spatial analysis of the differential travel time residuals between the two phases reveals significant short-wavelength variation and implies the existence of strong structural variability in the deep Earth. A linear N-S trending anomaly across the middle of the U.S. may reflect an asymmetric quasi-hemispherical structure deep within the inner core with boundaries of 99°W and 88°E.

  5. Detectability of temporal changes in fine structures near the inner core boundary beneath the eastern hemisphere

    Science.gov (United States)

    Yu, Wen-che

    2016-04-01

    The inner core boundary (ICB), where melting and solidification of the core occur, plays a crucial role in the dynamics of the Earth's interior. To probe temporal changes near the ICB beneath the eastern hemisphere, I analyze differential times of PKiKP (dt(PKiKP)), double differential times of PKiKP-PKPdf, and PKiKP coda waves from repeating earthquakes in the Southwest Pacific subduction zones. Most PKiKP differential times are within ±30 ms, comparable to inherent travel time uncertainties due to inter-event separations, and suggest no systematic changes as a function of calendar time. Double differential times measured between PKiKP codas and PKiKP main phases show promising temporal changes, with absolute values of time shifts of >50 ms for some observations. However, there are discrepancies among results from different seismographs in the same calendar time window. Negligible changes in PKiKP times, combined with changes in PKiKP coda wave times on 5 year timescales, favor a smooth inner core boundary with fine-scale structures present in the upper inner core. Differential times of PKiKP can be interpreted in the context of either melting based on translational convection, or growth based on thermochemical mantle-inner core coupling. Small dt(PKiKP) values with inherent uncertainties do not have sufficient resolution to distinguish the resultant longitudinal (melting) and latitudinal (growth) dependencies predicted on the basis of the two models on 5 year timescales.

  6. Earth's inner core: Innermost inner core or hemispherical variations?

    NARCIS (Netherlands)

    Lythgoe, K. H.; Deuss, A.; Rudge, J. F.; Neufeld, J. A.

    2014-01-01

    The structure of Earth's deep inner core has important implications for core evolution, since it is thought to be related to the early stages of core formation. Previous studies have suggested that there exists an innermost inner core with distinct anisotropy relative to the rest of the inner core.

  7. Earth's inner core: Innermost inner core or hemispherical variations?

    NARCIS (Netherlands)

    Lythgoe, K. H.; Deuss, A.; Rudge, J. F.; Neufeld, J. A.

    2014-01-01

    The structure of Earth's deep inner core has important implications for core evolution, since it is thought to be related to the early stages of core formation. Previous studies have suggested that there exists an innermost inner core with distinct anisotropy relative to the rest of the inner core.

  8. Seismic Structure in the Vicinity of the Inner Core Boundary beneath northeastern Asia

    Science.gov (United States)

    Ibourichene, A. S.; Romanowicz, B. A.

    2016-12-01

    The inner core boundary (ICB) separates the solid inner core from the liquid outer core. The crystallization of iron occurring at this limit induces the expulsion of lighter elements such as H, O, S, Si into the outer core, generating chemically-driven convection, which provides power for the geodynamo. Both the F layer, right above the ICB, and the uppermost inner core, are affected by this process so that their properties provide important constraints for a better understanding of core dynamics and, ultimately, the generation and sustained character of the earth's magnetic field. In this study, we investigate the evolution of model parameters (P-velocity, density and quality factor) with depth in the vicinity of the ICB. For this purpose, we combine observations of two body wave phases sensitive to this region: the PKP(DF) phase refracted in the inner core and the PKiKP reflected on the ICB. Variations in the PKP(DF)/PKiKP amplitude ratio and PKP(DF)-PKiKP differential travel times can be related to structure around the ICB. We use waveform data from earthquakes located in Sumatra and recorded by the dense USArray seismic network, which allows us to sample ICB structure beneath northeastern Asia. Observed waveforms are compared to synthetics computed using the DSM method (e.g., Geller et Takeuchi, 1995) in model AK135 (e.g., Montagner & Kennett, 1996) in order to measure amplitude and travel time anomalies. Previous studies (e.g., Tanaka, 1997 ; Cao and Romanowicz, 2004, Yu and Wen, 2006; Waszek and Deuss, 2011) have observed an hemispherical pattern in the vicinity of the ICB exhibiting a faster and more attenuated eastern hemisphere compared to the western hemisphere. The region studied is located in the eastern hemisphere. We find that, on average, travel time anomalies are consistent with previous studies of the eastern hemisphere, however, amplitude ratios are not. We conduct a parameter search for the 1D model that best fits our data. We also consider

  9. Molecular and Structural Basis of Inner Core Lipopolysaccharide Alterations in Escherichia coli

    Science.gov (United States)

    Klein, Gracjana; Müller-Loennies, Sven; Lindner, Buko; Kobylak, Natalia; Brade, Helmut; Raina, Satish

    2013-01-01

    It is well established that lipopolysaccharide (LPS) often carries nonstoichiometric substitutions in lipid A and in the inner core. In this work, the molecular basis of inner core alterations and their physiological significance are addressed. A new inner core modification of LPS is described, which arises due to the addition of glucuronic acid on the third heptose with a concomitant loss of phosphate on the second heptose. This was shown by chemical and structural analyses. Furthermore, the gene whose product is responsible for the addition of this sugar was identified in all Escherichia coli core types and in Salmonella and was designated waaH. Its deduced amino acid sequence exhibits homology to glycosyltransferase family 2. The transcription of the waaH gene is positively regulated by the PhoB/R two-component system in a growth phase-dependent manner, which is coordinated with the transcription of the ugd gene explaining the genetic basis of this modification. Glucuronic acid modification was observed in E. coli B, K12, R2, and R4 core types and in Salmonella. We also show that the phosphoethanolamine (P-EtN) addition on heptose I in E. coli K12 requires the product of the ORF yijP, a new gene designated as eptC. Incorporation of P-EtN is also positively regulated by PhoB/R, although it can occur at a basal level without a requirement for any regulatory inducible systems. This P-EtN modification is essential for resistance to a variety of factors, which destabilize the outer membrane like the addition of SDS or challenge to sublethal concentrations of Zn2+. PMID:23372159

  10. Three-dimensional structure of the inner core of rice dwarf virus

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Rice dwarf virus (RDV) is a double-shelled icosahedral virus.Using electron cryomicroscopy and computer reconstruction techniques, we have determined a 3.3 nm resolution three-dimensional (3D) structure of the inner shell capsid without the outer shell and viral RNA. The results show that the inner shell is a thin, densely packed, smooth structure, which provides a scaffold for the full virus. A total of 120 copies of the major inner shell capsid protein P3 forms 60 dimers arranged in a T=1 icosahedral lattice. A close examination on the subunit packing of the T=1 inner core P3 with that of the T=13l outer shell P8 indicated that P8 trimers connect with P3 through completely non-equivalent, yet highly specific, intermolecular interactions.

  11. Determination of the effect of initial inner-core structure on tropical cyclone intensification and track on a beta plane

    Science.gov (United States)

    Chen, Guanghua

    2016-08-01

    The sensitivity of TC intensification and track to the initial inner-core structure on a β plane is investigated using a numerical model. The results show that the vortex with large inner-core winds (CVEX-EXP) experiences an earlier intensification than that with small inner-core winds (CCAVE-EXP), but they have nearly the same intensification rate after spin-up. In the early stage, the convective cells associated with surface heat flux are mainly confined within the inner-core region in CVEX-EXP, whereas the vortex in CCAVE-EXP exhibits a considerably asymmetric structure with most of the convective vortices being initiated to the northeast in the outer-core region due to the β effect. The large inner-core inertial stability in CVEX-EXP can prompt a high efficiency in the conversion from convective heating to kinetic energy. In addition, much stronger straining deformation and PBL imbalance in the inner-core region outside the primary eyewall ensue during the initial development stage in CVEX-EXP than in CCAVE-EXP, which is conducive to the rapid axisymmetrization and early intensification in CVEX-EXP. The TC track in CVEX-EXP sustains a northwestward displacement throughout the integration, whereas the TC in CCAVE-EXP undergoes a northeastward recurvature when the asymmetric structure is dominant. Due to the enhanced asymmetric convection to the northeast of the TC center in CCAVE-EXP, a pair of secondary gyres embedded within the large-scale primary β gyres forms, which modulates the ventilation flow and thus steers the TC to move northeastward.

  12. Investigating the translation of Earth's inner core

    DEFF Research Database (Denmark)

    Day, Elizabeth A; Cormier, Vernon F; Geballe, Zachary M;

    2012-01-01

    The Earth’s inner core provides unique insights into processes that are occurring deep within our Earth today, as well as processes that occurred in the past. The seismic structure of the inner core is complex, and is dominated by anisotropic and isotropic differences between the Eastern...... and Western ‘hemispheres’ of the inner core. Recent geodynamical models suggest that this hemispherical dichotomy can be explained by a fast translation of the inner core. In these models one side of the inner core is freezing, while the other side is melting, leading to the development of different seismic...... properties on either side of the inner core. A simple translating model of the inner core, however, does not seem to easily explain all of the seismically observed features, including the innermost inner core; the observed sharp lateral gradient in seismic properties between the two hemispheres...

  13. On the existence and structure of a mush at the inner core boundary of the Earth

    CERN Document Server

    Deguen, Renaud; Brito, Daniel

    2008-01-01

    It has been suggested about 20 years ago that the liquid close to the inner core boundary (ICB) is supercooled and that a sizable mushy layer has developed during the growth of the inner core. The morphological instability of the liquid-solid interface which usually results in the formation of a mushy zone has been intensively studied in metallurgy, but the freezing of the inner core occurs in very unusual conditions: the growth rate is very small, and the pressure gradient has a key role, the newly formed solid being hotter than the adjacent liquid. We investigate the linear stability of a solidification front under such conditions, pointing out the destabilizing role of the thermal and solutal fields, and the stabilizing role of the pressure gradient. The main consequence of the very small solidification rate is the importance of advective transport of solute in liquid, which tends to remove light solute from the vicinity of the ICB and to suppress supercooling, thus acting against the destabilization of th...

  14. Structure of a mushy layer under hypergravity with implications for Earth's inner core

    Science.gov (United States)

    Huguet, Ludovic; Alboussière, Thierry; Bergman, Michael I.; Deguen, Renaud; Labrosse, Stéphane; Lesœur, Germain

    2016-03-01

    Crystallization experiments in the dendritic regime have been carried out in hypergravity conditions (from 1 to 1300 g) from an ammonium chloride solution (NH4Cl and H2O). A commercial centrifuge was equipped with a slip ring so that electric power (needed for a Peltier device and a heating element), temperature and ultrasonic signals could be transmitted between the experimental setup and the laboratory. Ultrasound measurements (2-6 MHz) were used to detect the position of the front of the mushy zone and to determine attenuation in the mush. Temperature measurements were used to control a Peltier element extracting heat from the bottom of the setup and to monitor the evolution of crystallization in the mush and in the liquid. A significant increase of solid fraction and attenuation in the mush is observed as gravity is increased. Kinetic undercooling is significant in our experiments and has been included in a macroscopic mush model. The other ingredients of the model are conservation of energy and chemical species, along with heat/species transfer between the mush and the liquid phase: boundary-layer exchanges at the top of the mush and bulk convection within the mush (formation of chimneys). The outputs of the model compare well with our experiments. We have then run the model in a range of parameters suitable for the Earth's inner core. This has shown the role of bulk mush convection for the inner core and the reason why a solid fraction very close to unity should be expected. We have also run melting experiments: after crystallization of a mush, the liquid has been heated from above until the mush started to melt, while the bottom cold temperature was maintained. These melting experiments were motivated by the possible local melting at the inner core boundary that has been invoked to explain the formation of the anomalously slow F-layer at the bottom of the outer core or inner core hemispherical asymmetry. Oddly, the consequences of melting are an increase in

  15. Dual-Aircraft Investigation of the Inner Core of Hurricane Norbert. Part II: Mesoscale Distribution of Ice Particles.

    Science.gov (United States)

    Houze, Robert A., Jr.; Marks, Frank D., Jr.; Black, Robert A.

    1992-06-01

    Horizontal fields of cloud microphysical parameters, vertical air motion, and horizontal wind at the 6-km level in Hurricane Norbert (1984) were obtained by mapping and interpolating data collected on board a WP-3D aircraft along numerous flight tracks executed within the central region of the storm. Although the storm was characterized by a strong vortex of winds reaching peak values > 50 m s1 all around the storm, the precipitation was concentrated on the southwest side of the storm. A sloping eyewall was located within 20 to 30 km of the eye. Stratiform precipitation dominated the region outside the eyewall. A 25-km-wide band of maximum stratiform precipitation was centered 60-70 km southwest of the storm center.The ice particles at flight level tended to be relatively large both in the eyewall and in the outer band of stratiform precipitation. Particles were smaller and more numerous (100-300 L1) in the zone between the eyewall and outer stratiform band. These particles occurred on the outside edges of the eyewall convective updrafts, indicating that they may have been produced by splintering in association with graupel formation in the updrafts. The large particles in the eyewall tended to be graupel. In the outer stratiform region, characterized by weak, average vertical air motion and an absence of strong convective drafts, the predominant particle type was aggregates.The region of large graupel particles in the eyewall coincided with the radius of maximum tangential wind and was apparently produced by the azimuthal advection of the graupel particles. Since graupel particles fall rapidly, they were not susceptible to advection out of the eyewall region by the weaker radial wind component. On the other hand, some of the more slowly falling, less dense aggregates produced in the eyewall region were evidently advected radially as well as azimuthally, thus accounting for the location of the outer region of maximum stratiform precipitation intensity.

  16. Using PKiKP coda to determine inner core structure: 1. Synthesis of coda envelopes using single-scattering theories

    Science.gov (United States)

    Leyton, Felipe; Koper, Keith D.

    2007-05-01

    Previous seismic studies have reported evidence of scattered seismic energy coming from the inner core (IC). This implies that the IC has lateral variations in structure or composition with a scale length of tens of kilometers. In the present study, we focus on synthesizing the coda following precritical PKiKP and try to determine the location of the heterogeneities that produce this coda, using previously reported observations as a guide. Using a single-scattering approximation and ray theory, we generate synthetic PKiKP coda envelopes from six distinctive places inside the Earth: within the lower mantle on the source and receiver side, along the core-mantle boundary on the source and receiver side, along the inner core boundary, and within the inner core. We use two approaches to generate synthetic coda from topography on a boundary surface and one that is appropriate for volumetric scattering. In our computations we calculate the arrival time, ray parameter, and amplitude of the seismic waves and take into account errors in the back azimuth, as well as source and receiver effects. We find that previously reported "spindle"-shaped or growing coda can only be produced from volumetric heterogeneities located in the shallowest 350 km of the IC; however, strong trade-offs between the different parameters describing the volumetric heterogeneities (i.e., characteristic wavelengths, RMS velocity or impedance contrast, and total volume) preclude the determination of a unique model. Additionally, we find that reasonable models of topography at the core-mantle boundary can produce large variations of the PKiKP amplitude due to focusing and defocusing effects. Therefore complexity at the inner core boundary is not necessarily required to account for dramatic amplitude variations in the direct PKiKP amplitudes.

  17. The effects of the solid inner core and nonhydrostatic structure on the earth's forced nutations and earth tides

    Science.gov (United States)

    De Vries, Dan; Wahr, John M.

    1991-01-01

    This paper computes the effects of the solid inner core (IC) on the forced nutations and earth tides, and on certain of the earth's rotational normal modes. The theoretical results are extended to include the effects of a solid IC and of nonhydrostatic structure. The presence of the IC is responsible for a new, almost diurnal, prograde normal mode which involves a relative rotation between the IC and fluid outer core about an equatorial axis. It is shown that the small size of the IC's effects on both nutations and tides is a consequence of the fact that the IC's moments of inertia are less than 1/1000 of the entire earth's.

  18. Observations of exotic inner core waves

    NARCIS (Netherlands)

    Waszek, Lauren; Deuss, A.F.

    2015-01-01

    The seismic structure of Earth’s inner core is highly complex, displaying strong anisotropy and further regional variations. However, few seismic waves are sensitive to the inner core and fundamental questions regarding the origin of the observed seismic features remain unanswered. Thus, new

  19. Three-dimensional structure of the inner core of rice dwarf virus

    Institute of Scientific and Technical Information of China (English)

    SHAO; Chenghua

    2001-01-01

    [1]Suzuki, N., Sugawara, M., Kusano, T. et al., Immunodetection of rice dwarf phytoreoviral protein in both insect and plant hosts, Virology, 1994, 202: 41.[2]Omura, T., Ishikawa, K., Hirano, H. et al., The outer capid protein of rice dwarf virus is encoded by genome segment S8, J. Gen. Virol., 1989, 70: 2759.[3]Lu, G. Y., Zhou, Z. H., Baker, M. L. et al., Structure of double-shelled rice dwarf virus, J.Virol., 1998, 72: 8541.[4]Reinisch, K. M., Nibert, M. L., Harrison, S. C., Structure of the reovirus core at 3.6 ? resolution, Nature, 2000, 404: 960.[5]Zhang, H., Zhang, J., Yu, X. et al., Visualization of protein-RNA interactions in cytoplasmic polyhedrosis virus, J. Virol., 1999, 73: 1624.[6]Zhou, Z. H., Hardt, S., Wang, B. et al., CTF determination of images of ice-embedded single particles using a graphics inter-face, J. Struct. Biol., 1996, 116: 216.[7]Zhou, Z. H., Chiu, W., Haskell, K. et al., Refinement of herpesvirus B-capsid using parallel supercomputers, Biophys. J., 1998, 74: 576.[8]Zhou, Z. H., He, J., Jakana, J. et al., Assembly of VP26 in HSV-1 inferred from structures of wild-type and recombinant cap-sids, Nature Struct. Biol., 1995, 2: 1026.[9]Grimes, J. M., Burroughs, J. N., Patrice, G. et al., The atomic structure of the bluetongue virus core, Nature, 1998, 395: 470.[10] Lawton, J. A., Estes, M. K., Prasad, B. V. V., Three-dimensional visualization of mRNA release from actively transcribing rotavirus particles, Nat. Struc. Bio., 1997, 4: 118.[11] Ueda, S., Masuta, C., Uyeda, I., Hypothesis on particle structure and assembly of rice dwarf phytoreovirus: interactions among multiple structural proteins, J.Gen.Virol., 1997, 78: 3135.[12] Kano, H., Koizumi, M., Noda, H. et al., Nucleotide sequence of rice dwarf virus(RDV) genome segment S3 coding for 114 K major core protein, Nucleic Acids Res., 1990, 18: 6700.[13] Nakata, M., Fukunaga, K., Suzuki, N., Polypeptide components of rice dwarf virus, Ann

  20. The NASA Cyclone Global Navigation Satellite System (CYGNSS): A Constellation of Bi-static Ocean Scatterometer Microsatellites to Probe the Inner Core of Hurricanes

    Science.gov (United States)

    Ruf, C. S.; Clarizia, M. P.; Ridley, A. J.; Gleason, S.; O'Brien, A.

    2014-12-01

    The Cyclone Global Navigation Satellite System (CYGNSS) is the first NASA Earth Ventures spaceborne mission. CYGNSS consists of a constellation of eight small observatories carried into orbit on a single launch vehicle. The eight satellites comprise a constellation that flies closely together to measure the ocean surface wind field with unprecedented temporal resolution and spatial coverage, under all precipitating conditions, and over the full dynamic range of wind speeds experienced in a TC. The 8 CYGNSS observatories will fly in 500 km circular orbits at a common inclination of ~35°. Each observatory includes a Delay Doppler Mapping Instrument (DDMI) consisting of a modified GPS receiver capable of measuring surface scattering, a low gain zenith antenna for measurement of the direct GPS signal, and two high gain nadir antennas for measurement of the weaker scattered signal. Each DDMI is capable of measuring 4 simultaneous bi-static reflections, resulting in a total of 32 wind measurements per second across the globe by the full constellation. Simulation studies will be presented which examine the sampling as functions of various orbit parameters of the constellation. For comparison purposes, a similar analysis is conducted using the sampling of several past and present conventional spaceborne ocean wind scatterometers. Differences in the ability of the sensors to resolve the evolution of the TC inner core will be examined. The CYGNSS observatories are currently in Phase C development. An update on the current status of the mission will be presented, including the expected precision, accuracy and spatial and temporal sampling properties of the retrieved winds.

  1. Physical Properties of Iron in the Inner Core

    CERN Document Server

    Steinle-Neumann, G; Cohen, R E; Steinle-Neumann, Gerd; Stixrude, Lars

    2002-01-01

    The Earth's inner core plays a vital role in the dynamics of our planet and is itself strongly exposed to dynamic processes as evidenced by a complex pattern of elastic structure. To gain deeper insight into the nature of these processes we rely on a characterization of the physical properties of the inner core which are governed by the material physics of its main constituent, iron. Here we review recent research on structure and dynamics of the inner core, focusing on advances in mineral physics. We will discuss results on core composition, crystalline structure, temperature,and various aspects of elasticity. Based on recent computational results, we will show that aggregate seismic properties of the inner core can be explained by temperature and compression effects on the elasticity of pure iron, and use single crystal anisotropy to develop a speculative textural model of the inner core that can explain major aspects of inner core anisotropy.

  2. The Earth's Inner Core: a Black Box

    Science.gov (United States)

    Tkalčić, Hrvoje

    2016-04-01

    The Earth's inner core continues to provoke interest and interaction among various disciplines within the deep Earth scientific community for many reasons, including the following: i) The phase diagram of iron and its alloys at high pressures and temperatures is still in a state of investigation, and several crystalographic phases of iron and/or their aggregates have been proposed to be stable at inner core conditions. Seismological datasets have increased in size, but there is a serious trade-off between isotropic and anisotropic velocity structure. This is further exacerbated by the non-uniqueness of the inverse problem in which travel time data are modeled by volumetric changes in isotropic/anisotropic structure. These datasets are nevertheless invaluable, and their further growth through receiver installations in remote regions will further constrain this problem. ii) Radial and lateral variations in inner core structure have been intensively studied and confirmed, both in terms of velocity and attenuation. Studying the latter is complicated since another trade-off exists - that between the viscoelastic and scattering origin of attenuation. There is an ongoing debate about the existence of the innermost inner core and the geodynamical mechanism responsible for the seismologically observed east-west dichotomy in isotropic velocity. The growing travel time and waveform datasets, both from individual stations and arrays, hold the key to solving these problems. iii) The growth mechanism of the inner core is in dispute; its age is still unknown, and it is not completely understood how its growing front crystallizes. The seismological datasets are arguably less potent in providing direct answers to this question. Nonetheless, there is some potential in studying the texture present in the outermost inner core, the velocity gradient at the bottom of the outer core, and the nature of the inner core boundary using waveform simulations and the coda of the seismic phases

  3. Molecular and structural basis of inner core lipopolysaccharide alterations in Escherichia coli: incorporation of glucuronic acid and phosphoethanolamine in the heptose region.

    Science.gov (United States)

    Klein, Gracjana; Müller-Loennies, Sven; Lindner, Buko; Kobylak, Natalia; Brade, Helmut; Raina, Satish

    2013-03-22

    It is well established that lipopolysaccharide (LPS) often carries nonstoichiometric substitutions in lipid A and in the inner core. In this work, the molecular basis of inner core alterations and their physiological significance are addressed. A new inner core modification of LPS is described, which arises due to the addition of glucuronic acid on the third heptose with a concomitant loss of phosphate on the second heptose. This was shown by chemical and structural analyses. Furthermore, the gene whose product is responsible for the addition of this sugar was identified in all Escherichia coli core types and in Salmonella and was designated waaH. Its deduced amino acid sequence exhibits homology to glycosyltransferase family 2. The transcription of the waaH gene is positively regulated by the PhoB/R two-component system in a growth phase-dependent manner, which is coordinated with the transcription of the ugd gene explaining the genetic basis of this modification. Glucuronic acid modification was observed in E. coli B, K12, R2, and R4 core types and in Salmonella. We also show that the phosphoethanolamine (P-EtN) addition on heptose I in E. coli K12 requires the product of the ORF yijP, a new gene designated as eptC. Incorporation of P-EtN is also positively regulated by PhoB/R, although it can occur at a basal level without a requirement for any regulatory inducible systems. This P-EtN modification is essential for resistance to a variety of factors, which destabilize the outer membrane like the addition of SDS or challenge to sublethal concentrations of Zn(2+).

  4. Sound Velocity Measurements in Textured hcp-Iron and the Anisotropy and Structure of Earth's Inner Core

    Science.gov (United States)

    Antonangeli, D.; Occelli, F.; Badro, J.; Requardt, H.; Fiquet, G.; Krisch, M.

    2003-12-01

    Seismological studies show that the Earth's inner core is elastically anisotropic. The anisotropy has an axial symmetry and an amplitude of about 3-4%, with the fast direction oriented parallel to the Earth's rotation axis. Several hypotheses have been proposed to explain this feature, but the lack of evidence from mineral physics does not allow to address them. Indeed, the experimental determination of sound velocity anisotropy in hcp-iron, the main constituent of the inner core, is of primary importance. Studies include first-principle calculations [1-5] and x-ray radial diffraction measurements [6], but the results show general disagreement, not only in magnitude, but in direction as well. We will report new inelastic x-ray scattering (IXS) data on polycrystalline hcp-iron as a function of pressure, complementing and extending previous IXS data [7]. The derived longitudinal and transverse sound velocities will be compared with the calculations and the experimental results present in literature. Furthermore, the issue of elastic anisotropy will be addressed. Taking advantage of the texturing developed by uniaxially compressed hcp-metals [8], and making use of a properly designed diamond anvil cell characterized by an angular aperture of more than \\begin{math} 90^{o} , we measured the sound velocity at 22 and 112 GPa in two different geometries with respect to the compression axis, probing the longitudinal sound propagation at \\begin{math} 50^{o} and \\begin{math} 90^{o} with respect to it. A difference in acoustic sound velocity of about 5% has been detected at the highest pressure. This effective anisotropy on a textured polycrystalline sample is comparable with the one observed in the Earth, further relaxing the requirement of a nearly perfect alignment of iron crystal grains sustained by previous theoretical investigations [1,4]. [1] L. Stixrude, R.E. Cohen, Science 267, 1972 (1995). [2] P. Soderlind et al., Phys. Rev. B 53, 14063 (1996). [3] R. E. Cohen et

  5. Effect of different inner core diameters on structural strength of cannulated pedicle screws under various lumbar spine movements.

    Science.gov (United States)

    Chang, Chia-Ming; Lai, Yu-Shu; Cheng, Cheng-Kung

    2017-08-15

    Currently, cannulated pedicle screws have been widely used in minimal invasive or navigation techniques. However, the stress distribution and the strength of different core diameters of cannulated screw are not clear. This study aimed to investigate the mechanical strength of cannulated screws with different inner core diameter under various lumbar spine movements using finite element analysis. The results showed that the von-Mises stress of a cannulated screw was larger than that of a solid screw in all loading conditions, especially above 2 mm in cannulated core diameter. In lateral bending, extension, and flexion, the maximum von-Mises stress was found approximate to the proximal thread for all types of screws. In rotation condition, the maximum von-Mises stress was located at the middle of the screw. Additionally, the difference in stiffness of instrumented levels was not significant among four screws under the same loading condition. Cannulated screws could provide enough stability for the vertebral body fusion comparing to solid screws. The diameter of cannulated core is suggested not to exceed 2.0 mm.

  6. Thermal and compositional stratification of the inner core

    CERN Document Server

    Labrosse, Stéphane

    2014-01-01

    The improvements on the knowledge of the seismic structure of the inner core and the complexities thereby revealed ask for a dynamical origin. Sub-solidus convection was one of the early suggestions to explain the seismic anisotropy but requires an unstable density gradient either from thermal or compositional origin, or both. Temperature and composition profiles in the inner core are computed using a unidimensional model of core evolution including diffusion in the inner core and fractional crystallization at the the inner core boundary (ICB). The thermal conductivity of the core has been recently revised upwardly and, moreover, found increasing with depth. Values of the heat flow across the core mantle boundary (CMB) sufficient to maintain convection in the whole outer core are not sufficient to make the temperature in the inner core super-isentropic and therefore prone to thermal instability. An unreasonably high CMB heat flow is necessary to this end. The compositional stratification results from a compet...

  7. Dependence of Hurricane Intensity and Structures on Vertical Resolution and Time-Step Size

    Institute of Scientific and Technical Information of China (English)

    Da-Lin ZHANG; Xiaoxue WANG

    2003-01-01

    In view of the growing interests in the explicit modeling of clouds and precipitation, the effects of varyingvertical resolution and time-step sizes on the 72-h explicit simulation of Hurricane Andrew (1992) arestudied using the Pennsylvania State University/National Center for Atmospheric Research (PSU/NCAR)mesoscale model (i.e., MMS) with the finest grid size of 6 km. It is shown that changing vertical resolutionand time-step size has significant effects on hurricane intensity and inner-core cloud/precipitation, butlittle impact on the hurricane track. In general, increasing vertical resolution tends to produce a deeperstorm with lower central pressure and stronger three-dimensional winds, and more precipitation. Similareffects, but to a less extent, occur when the time-step size is reduced. It is found that increasing thelow-level vertical resolution is more efficient in intensifying a hurricane, whereas changing the upper-levelvertical resolution has little impact on the hurricane intensity. Moreover, the use of a thicker surface layertends to produce higher maximum surface winds. It is concluded that the use of higher vertical resolution,a thin surface layer, and smaller time-step sizes, along with higher horizontal resolution, is desirable tomodel more realistically the intensity and inner-core structures and evolution of tropical storms as well asthe other convectively driven weather systems.

  8. Heterogeneity and anisotropy of Earth's inner core

    NARCIS (Netherlands)

    Deuss, Arwen

    2014-01-01

    Seismic observations provide strong evidence that Earth's inner core is anisotropic, with larger velocity in the polar than in the equatorial direction. The top 60-80 km of the inner core is isotropic; evidence for an innermost inner core is less compelling. The anisotropy is most likely due to alig

  9. Heterogeneity and anisotropy of Earth's inner core

    NARCIS (Netherlands)

    Deuss, Arwen

    2014-01-01

    Seismic observations provide strong evidence that Earth's inner core is anisotropic, with larger velocity in the polar than in the equatorial direction. The top 60-80 km of the inner core is isotropic; evidence for an innermost inner core is less compelling. The anisotropy is most likely due to

  10. Using pre-critical PKiKP-PcP phases to constrain the regional structures of the inner core boundary beneath East Asia

    Science.gov (United States)

    Shen, Zhongyin; Ai, Yinshuang; He, Yumei; Jiang, Mingming

    2016-03-01

    We collected 177 pre-critical PKiKP-PcP records, assembling a wealth of traveltime and amplitude data. These observations sample the inner core boundary (ICB) beneath East Asia with good spatial coverage. Combined with previous studies, our results demonstrate a 100-km-wide anomaly with positive PKiKP-PcP traveltime residuals surrounded by negatives beneath the Yellow Sea area (123°E, 33°N) (Yellow Sea anomaly). After correcting the elliptic effects and mantle Vp heterogeneities based on the tomography models, the residuals of the Yellow Sea anomaly remain at least 0.6 s faster than those of the surrounding areas, suggesting a thickening of 2-3 km between the ICB and core mantle boundary (CMB). Due to the negative CMB topography along the western Pacific rim, we attribute this anomaly mainly to negative ICB topography. Across the northern border of the Yellow Sea anomaly, PKiKP/PcP amplitude ratios increase by approximately 50% from north to south, which can be explained by an approximately 0.6 g/cm3 raise in ICB density contrast. These traveltime and amplitude features suggest a mosaic structure at the ICB beneath the Yellow Sea areas.

  11. Earth's Inner Core dynamics induced by the Lorentz force

    CERN Document Server

    Lasbleis, M; Cardin, P; Labrosse, S

    2015-01-01

    Seismic studies indicate that the Earth's inner core has a complex structure and exhibits a strong elastic anisotropy with a cylindrical symmetry. Among the various models which have been proposed to explain this anisotropy, one class of models considers the effect of the Lorentz force associated with the magnetic field diffused within the inner core. In this paper we extend previous studies and use analytical calculations and numerical simulations to predict the geometry and strength of the flow induced by the poloidal component of the Lorentz force in a neutrally or stably stratified growing inner core, exploring also the effect of different types of boundary conditions at the inner core boundary (ICB). Unlike previous studies, we show that the boundary condition that is most likely to produce a significant deformation and seismic anisotropy is impermeable, with negligible radial flow through the boundary. Exact analytical solutions are found in the case of a negligible effect of buoyancy forces in the inne...

  12. Rotation and Magnetism of Earth's Inner Core

    Science.gov (United States)

    Glatzmaier; Roberts

    1996-12-13

    Three-dimensional numerical simulations of the geodynamo suggest that a super- rotation of Earth's solid inner core relative to the mantle is maintained by magnetic coupling between the inner core and an eastward thermal wind in the fluid outer core. This mechanism, which is analogous to a synchronous motor, also plays a fundamental role in the generation of Earth's magnetic field.

  13. Melting of the Earth's inner core.

    Science.gov (United States)

    Gubbins, David; Sreenivasan, Binod; Mound, Jon; Rost, Sebastian

    2011-05-19

    The Earth's magnetic field is generated by a dynamo in the liquid iron core, which convects in response to cooling of the overlying rocky mantle. The core freezes from the innermost surface outward, growing the solid inner core and releasing light elements that drive compositional convection. Mantle convection extracts heat from the core at a rate that has enormous lateral variations. Here we use geodynamo simulations to show that these variations are transferred to the inner-core boundary and can be large enough to cause heat to flow into the inner core. If this were to occur in the Earth, it would cause localized melting. Melting releases heavy liquid that could form the variable-composition layer suggested by an anomaly in seismic velocity in the 150 kilometres immediately above the inner-core boundary. This provides a very simple explanation of the existence of this layer, which otherwise requires additional assumptions such as locking of the inner core to the mantle, translation from its geopotential centre or convection with temperature equal to the solidus but with composition varying from the outer to the inner core. The predominantly narrow downwellings associated with freezing and broad upwellings associated with melting mean that the area of melting could be quite large despite the average dominance of freezing necessary to keep the dynamo going. Localized melting and freezing also provides a strong mechanism for creating seismic anomalies in the inner core itself, much stronger than the effects of variations in heat flow so far considered.

  14. Elastic anisotropy of Earth's inner core.

    Science.gov (United States)

    Belonoshko, Anatoly B; Skorodumova, Natalia V; Rosengren, Anders; Johansson, Börje

    2008-02-08

    Earth's solid-iron inner core is elastically anisotropic. Sound waves propagate faster along Earth's spin axis than in the equatorial plane. This anisotropy has previously been explained by a preferred orientation of the iron alloy hexagonal crystals. However, hexagonal iron becomes increasingly isotropic on increasing temperature at pressures of the inner core and is therefore unlikely to cause the anisotropy. An alternative explanation, supported by diamond anvil cell experiments, is that iron adopts a body-centered cubic form in the inner core. We show, by molecular dynamics simulations, that the body-centered cubic iron phase is extremely anisotropic to sound waves despite its high symmetry. Direct simulations of seismic wave propagation reveal an anisotropy of 12%, a value adequate to explain the anisotropy of the inner core.

  15. The signature of inner core nucleation on the geodynamo

    Science.gov (United States)

    Landeau, Maylis; Aubert, Julien; Olson, Peter

    2016-04-01

    Energy considerations indicate that the power delivered to the present-day geodynamo comes mainly from the growth of the solid inner core, through light element and latent heat releases. However, estimates of present-day core heat loss predict that inner core nucleation (ICN) likely occurred within the past 1.5 Gyr, implying that the geodynamo operated over most of its history without the help of inner core growth. We use numerical dynamo simulations linked by thermochemical evolution of the core to identify signatures of ICN in the paleomagnetic field and possible ICN footprints in paleomagnetic data. We select a set of dynamo simulation parameters that generates a magnetic field structure compliant with the present-day geomagnetic field. We then use thermochemical evolution to project this dynamo into the past, backward-evolving the inner core size and the dynamo forcing parameters. We obtain a time average dipole moment prior to ICN comparable to the post-ICN dipole moment, consistent with paleointensity measurements, despite a power reduction of nearly two orders of magnitude. Our results predict that the surface geomagnetic field was dominated by an axial dipole prior to ICN, although it contained an axial octupole component stronger than present-day. This stronger octupole was induced by polar downwellings prior to ICN, which might be resolvable using paleomagnetic directions.

  16. The inner core thermodynamics of the tropical cyclone boundary layer

    Science.gov (United States)

    Williams, Gabriel J.

    2016-10-01

    Although considerable progress has been made in understanding the inner-core dynamics of the tropical cyclone boundary layer (TCBL), our knowledge of the inner-core thermodynamics of the TCBL remains limited. In this study, the inner-core budgets of potential temperature (θ), specific humidity ( q), and reversible equivalent potential temperature (θ _e) are examined using a high-resolution multilevel boundary layer model. The potential temperature budgets show that the heat energy is dominated by latent heat release in the eyewall, evaporative cooling along the outer edge of the eyewall, and upward surface fluxes of sensible and latent heat from the underlying warm ocean. It is shown that the vertical θ advection overcompensates the sum of radial advective warming from the boundary layer outflow jet and latent heating for the development of cooling in the eyewall within the TCBL. The moisture budgets show the dominant upward transport of moisture in the eyewall updrafts, partly by the boundary-layer outflow jet from the bottom eye region, so that the eyewall remains nearly saturated. The θ _e budgets reveal that the TCBL is maintained thermodynamically by the upward surface flux of higher-θ _e air from the underlying warm ocean, the radial transport of low-θ _e air from the outer regions of the TCBL, and the dry adiabatic cooling associated by eyewall updrafts. These results underscore the significance of vertical motion and the location of the boundary layer outflow jet in maintaining the inner core thermal structure of the TCBL.

  17. The feasibility of thermal and compositional convection in Earth’s inner core

    NARCIS (Netherlands)

    Lythgoe, K. H.; Rudge, J. F.; Neufeld, J. A.; Deuss, A.F.

    2015-01-01

    Inner core convection, and the corresponding variations in grain size and alignment, has been proposed to explain the complex seismic structure of the inner core, including its anisotropy, lateral variations and the F-layer at the base of the outer core. We develop a parametrized convection model to

  18. The feasibility of thermal and compositional convection in Earth’s inner core

    NARCIS (Netherlands)

    Lythgoe, K. H.; Rudge, J. F.; Neufeld, J. A.; Deuss, A.F.

    2015-01-01

    Inner core convection, and the corresponding variations in grain size and alignment, has been proposed to explain the complex seismic structure of the inner core, including its anisotropy, lateral variations and the F-layer at the base of the outer core. We develop a parametrized convection model to

  19. The existence of radial anisotropy in Earth's upper inner core revealed from seismic normal mode observations

    NARCIS (Netherlands)

    Lythgoe, Karen H.; Deuss, Arwen

    2015-01-01

    As we strive to understand the most remote region of our planet, one critical area of investigation is the uppermost inner core since its structure is related to solidification of outer core material at the inner core boundary (ICB). Previous seismic studies have used body waves to show that the top

  20. The existence of radial anisotropy in Earth's upper inner core revealed from seismic normal mode observations

    NARCIS (Netherlands)

    Lythgoe, Karen H.; Deuss, Arwen

    2015-01-01

    As we strive to understand the most remote region of our planet, one critical area of investigation is the uppermost inner core since its structure is related to solidification of outer core material at the inner core boundary (ICB). Previous seismic studies have used body waves to show that the top

  1. Earth Inner Core Periodic Motion due to Pressure Difference Induced by Tidal Acceleration

    CERN Document Server

    Wolf, M

    2013-01-01

    The inner structure of the earth is still a topic of discussion. Seismic measurements showed a structure of solid, liquid, solid which describes the mantle, outer core and inner core with the inner core in the center. The analysis of waveform doublets suggests now that the inner core is out of center and even of faster rotation than the mantel and crust. From the sum of Buoyancy and Gravity on the earth inner core, the position energy is plotted and together with the tangential tidal acceleration, it is derived that Earth Inner Core cannot be in a center position without additional force. The Earth Core System is explained as Hydrodynamic Bearing. The Eccentricities out of nutation due to the effects from the sun and moon are calculated as an approximation.

  2. ABSTRACTS Preliminary Study of Strategic Inner Cores

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    When a strategic entity attempts to make a dicision, first the project must be m accoroance wlm its strategic framework as well as make the strategic inner cores prominent. The existing theories of development strategy indicate that the formation of the framework can be divided into the following parts: inside and outside environments, purpose, goal, key points, and countermeasures. The strategic inner cores that put forward by this paper is the intensification and advancement for the theory of strategic framework, strategic orientation, strategic vision and main line are inciuded. Appearance of these ideas have improved the theory and enhanced strategic practice.

  3. Multiscale model of global inner-core anisotropy induced by hcp-alloy plasticity

    Science.gov (United States)

    Cardin, P.; Deguen, R.; Lincot, A.; Merkel, S.

    2016-12-01

    The Earth's solid inner core exhibits a global seismic anisotropy of several percents. It results from a coherent alignment of anisotropic Fe alloy crystals through the inner-core history that can be sampled by present-day seismic observations. By combining self-consistent polycrystal plasticity, inner-core formation models, Monte-Carlo search for elastic moduli, and simulations of seismic measurements, we introduce a multiscale model that can reproduce a global seismic anisotropy of several percents aligned with the Earth's rotation axis. Conditions for a successful model are an hexagonal close packed structure for the inner-core Fe alloy, plastic deformation by pyramidal slip, and large-scale flow induced by a low-degree inner-core formation model. For global anisotropies ranging between 1 and 3%, the elastic anisotropy in the single crystal ranges from 5 to 20% with larger velocities along the c axis.

  4. Is Missing Xenon in the Earth's Inner Core

    CERN Document Server

    Zhu, Li; Zou, Guangtian; Ma, Yanming

    2013-01-01

    Atmospheric studies of Earth have shown that more than 90% of xenon (Xe) is depleted if compared to the abundance of chondritic meteorites1,2. This missing Xe paradox remains a long-standing mystery and has become an extensive debate2-18. Earlier high pressure experimental and theoretical studies3-5 that were unable to find the reaction of Xe with iron (Fe), the main constituent of the Earth's inner core, seemingly excluded the Earth's inner core from the Xe reservoir. Here we report the first evidence on the chemical reaction of Xe with Fe at conditions of Earth's inner core predicted through our developed first-principles structure searching technique unbiased by any known structural knowledge. We find that Xe and Fe form stable inter-metallic compound of XeFe3 stoichiometry by adopting a Cu3Au-type cubic structure. By virtue of an unusual Xe -> Fe charge transfer, Xe loses its chemical inertness by opening up the completed filled 5p electron shell and thereby functions as a 5p-like element, while Fe is neg...

  5. When the Earth's Inner Core Shuffles

    Science.gov (United States)

    Tkalcic, H.; Young, M. K.; Bodin, T.; Ngo, S.; Sambridge, M.

    2011-12-01

    Shuffling is a tribal dance recently adapted by teenagers as a street dance. In one of the most popular moves, the so-called "Running Man", a stomp forward on one foot, shifted without being lifted from the ground, is followed by a change of position backwards on the same foot. Here, we present strong observational evidence from a newly observed collection of earthquake doublets that the Earth's inner core "shuffles" exhibiting both prograde and retrograde rotation in the reference frame of the mantle. This discovery is significant on several levels. First, the observed pattern consists of intermittent intervals of quasi-locked and differentially rotating inner core with respect to the Earth's mantle. This means that the angular alignment of the inner core and mantle oscillates in time over the past five decades. Jolting temporal changes are revealed, indicating that during the excursions from the quasi-locked state, the Earth's inner core can rotate both faster and slower than the rest of the planet, thus exhibiting both eastward and westward rotation. According to our results, a short time interval (on the order of one to two years) is needed for the inner core to accelerate to a differential rotation rate of several degrees per year, and typically a slightly longer time is needed to decelerate down to a negligibly small differential rotation rate. These time scales are in agreement with experimental spin-up times obtained when the magnetic torque alone is used to accelerate the inner core. Second, when we integrate the rotation rate over different time intervals, it is possible to explain discrepancies between the body wave and normal modes results for the rate of the inner core differential rotation found by previous authors. We show that the integrated shift in angular alignment and average rotation rates (previously determined to be constant) in normal mode studies are much smaller that those for the body waves. The repeating earthquakes from the South

  6. Slow differential rotation of the Earth's inner core indicated by temporal changes in scattering

    Science.gov (United States)

    Vidale; Dodge; Earle

    2000-05-25

    The finding that the Earth's inner core might be rotating faster than the mantle has important implications for our understanding of core processes, including the generation of the Earth's magnetic field. But the reported signal is subtle--a change of about 0.01 s per year in the separation of two seismic waves with differing paths through the core. Subsequent studies of such data have generally supported the conclusion that differential rotation exists, but the difficulty of accurately locating historic earthquakes and possible biases induced by strong lateral variations in structure near the core-mantle boundary have raised doubt regarding the proposed inner-core motion. Also, a study of free oscillations constrained the motion to be relatively small compared to previous estimates and it has been proposed that the interaction of inner-core boundary topography and mantle heterogeneity might lock the inner core to the mantle. The recent detection of seismic waves scattered in the inner core suggests a simple test of inner-core motion. Here we compare scattered waves recorded in Montana, USA, from two closely located nuclear tests at Novaya Zemlya, USSR, in 1971 and 1974. The data show small but coherent changes in scattering which point toward an inner-core differential rotation rate of 0.15 degrees per year--consistent with constraints imposed by the free-oscillation data.

  7. Viscosity near Earth's solid inner core

    Science.gov (United States)

    Smylie

    1999-04-16

    Anomalous splitting of the two equatorial translational modes of oscillation of Earth's solid inner core is used to estimate the effective viscosity just outside its boundary. Superconducting gravimeter observations give periods of 3.5822 +/- 0.0012 (retrograde) and 4.0150 +/- 0.0010 (prograde) hours. With the use of Ekman layer theory to estimate viscous drag forces, an inferred single viscosity of 1.22 x 10(11) Pascal seconds gives calculated periods of 3.5839 and 4.0167 hours for the two modes, close to the observed values. The large effective viscosity is consistent with a fluid, solid-liquid mixture surrounding the inner core associated with the "compositional convection" that drives Earth's geodynamo.

  8. Is inner core seismic anisotropy a marker of plastic flow of cubic iron?

    CERN Document Server

    Lincot, A; Cardin, Philippe

    2015-01-01

    This paper investigates whether observations of seismic anisotropy are compatible with a cubic structure of the inner core Fe alloy. We assume that anisotropy is the result of plastic deformation within a large scale flow induced by preferred growth at the inner core equator. Based on elastic moduli from the literature, bcc- or fcc-Fe produce seismic anisotropy well below seismic observations ($\\textless{}0.4\\%$). A Monte-Carlo approach allows us to generalize this result to any form of elastic anisotropy in a cubic system. Within our model, inner core global anisotropy is not compatible with a cubic structure of Fe alloy. Hence, if the inner core material is indeed cubic, large scale coherent anisotropic structures, incompatible with plastic deformation induced by large scale flow, must be present.

  9. Regional variation of inner core anisotropy from seismic normal mode observations.

    Science.gov (United States)

    Deuss, Arwen; Irving, Jessica C E; Woodhouse, John H

    2010-05-21

    Earth's solid inner core is surrounded by a convecting liquid outer core, creating the geodynamo driving the planet's magnetic field. Seismic studies using compressional body waves suggest hemispherical variation in the anisotropic structure of the inner core, but are poorly constrained because of limited earthquake and receiver distribution. Here, using normal mode splitting function measurements from large earthquakes, based on extended cross-coupling theory, we observe both regional variations and eastern versus western hemispherical anisotropy in the inner core. The similarity of this pattern with Earth's magnetic field suggests freezing-in of crystal alignment during solidification or texturing by Maxwell stress as origins of the anisotropy. These observations limit the amount of inner core super rotation, but would be consistent with oscillation.

  10. Hurricane damaged fixed platforms and wellhead structures

    Energy Technology Data Exchange (ETDEWEB)

    Shuttleworth, E.P.; Frieze, P.A.

    1998-03-01

    The objective of this study was to review data on damages to offshore platforms with a view to determining their suitability for further exploitation and analysis through a preliminary assessment of trends in the data when viewed from a risk standpoint. To realise this objective, a database on hurricane and other storm related damages was generated and past design practice, particularly concerning environmental load levels, was established. Information was gathered on extreme wave heights, damages, platform details, pushover analyses and structural frame load tests. The information was obtained through: a literature survey of journals, conference proceedings, design codes and guidelines; approaches to organisations in the offshore industry with significant experience of hurricanes, storm-damaged structures and pushover analyses; and interrogation of three major databases on offshore storm and other damages - PMB, MMS and WOAD. (author)

  11. Multiscale model of global inner-core anisotropy induced by hcp-alloy plasticity

    CERN Document Server

    Lincot, A; Deguen, R; Merkel, Sébastien

    2016-01-01

    $\\bullet$ Multiscale model of inner-core anisotropy produced by hcp alloy deformation$\\bullet$ 5 to 20% single-crystal elastic anisotropy and plastic deformation by pyramidal slip $\\bullet$ Low-degree inner-core formation model with faster crystallization at the equatorThe Earth's solid inner-core exhibits a global seismic anisotropy of several percents. It results from a coherent alignment of anisotropic Fe-alloy crystals through the inner-core history that can be sampled by present-day seismic observations. By combining self-consistent polycrystal plasticity, inner-core formation models, Monte-Carlo search for elastic moduli, and simulations of seismic measurements, we introduce a multiscale model that can reproduce a global seismic anisotropy of several percents aligned with the Earth's rotation axis. Conditions for a successful model are an hexagonal-close-packed structure for the inner-core Fe-alloy, plastic deformation by pyramidal \\textless{}c+a\\textgreater{} slip, and large-scale flow induced by a low...

  12. Imaging the inner core under Africa and Europe

    Science.gov (United States)

    Irving, J. C. E.

    2016-05-01

    The inner core under Africa is thought to be a region where the nature of inner core texture changes: from the strongly anisotropic 'western' part of the inner core to the weakly anisotropic, or isotropic 'eastern' part of the inner core. Additionally, observations of a difference in isotropic velocity between the two hemispheres have been made. A very large new dataset of simultaneous PKPdf and PKPbc observations, on which differential travel times have been measured, is used to examine the upper 360 km of the inner core under Europe, Africa and the surrounding oceans. Inversion of the differential travel time data for laterally varying inner core anisotropy reveals that inner core anisotropy is stronger under central Africa and the Atlantic Ocean than under the western Indian Ocean. No hemispherical pattern is present in Voigt isotropic velocities, indicating that the variation in anisotropy is due to differing degrees of crystal alignment in the inner core, not material differences. When anisotropy is permitted to change with depth, the upper east-most part of the study region shows weaker anisotropy than the central and western regions. When depth dependence in the inner core is neglected the hemisphere boundary is better represented as a line at 40°E than one at 10°E, however, it is apparent that the variation of anisotropy as a function of depth means that one line of longitude cannot truly separate the more and less anisotropic regions of the inner core. The anisotropy observed in the part of the inner core under Africa which lies in the 'western' hemisphere is much weaker than that under central America, showing that the western hemisphere is not uniformly anisotropic. As the region of low anisotropy spans a significant depth extent, it is likely that heterogeneous heat fluxes in the core, which may cause variations in inner core anisotropy, have persisted for several hundred million years.

  13. The forced precession of the Moon's inner core

    Science.gov (United States)

    Dumberry, Mathieu; Wieczorek, Mark A.

    2016-07-01

    The tilt angle of the 18.6 year precession of the Moon's solid inner core is unknown, but it is set by a balance between gravitational and pressure torques acting on its elliptical figure. We show here that to first order, the angle of precession of the inner core of a planetary body is determined by the frequency of the free inner core nutation, ωficn, relative to the precession frequency, Ωp. If |ωficn|≪|Ωp|, the inner core is blind to the gravitational influence of the mantle. If |ωficn|≫|Ωp|, the inner core is gravitationally locked to the mantle and is nearly aligned with it. If ωficn≈Ωp, large inner core tilt angles can result from resonant excitation. Viscous inner core relaxation and electromagnetic coupling can attenuate large tilt angles. For the specific case of the Moon, we show that ωficn is to within a factor of 2 of Ωp = 2π/18.6 yr-1. For a rigid inner core, this implies a tilt of 2 to 5° with respect to the mantle, and larger if ωficn is very close to Ωp. More modest tilt angles between 0 and 0.5° result if viscous relaxation within the inner core occurs on a timescale of one lunar day. Predictions from our model may be used in an attempt to detect the gravity signal resulting from a tilted inner core, to determine the past history of the inner core tilt angle, and to assess models of dynamo generation powered by differential rotation at the core-mantle and inner core boundaries.

  14. The Azimuthally Averaged Boundary Layer Structure of a Numerically Simulated Major Hurricane

    Science.gov (United States)

    2015-08-14

    intensifying primary and forming secondary eyewalls is found to be nonlinear. At large radii, exterior to the eyewalls, Ekman -like balance as traditionally...defined, is found to hold true. Where significant departures from Ekman -like balance are found, the departures are characterized by large vertical...hurricane’s inner core boundary layer is found to be nonlinear There are departures from Ekman -like balance in the hurricane boundary layer Azimuthally

  15. Phosphoethanolamine addition to the Heptose I of the Lipopolysaccharide modifies the inner core structure and has an impact on the binding of Polymyxin B to the Escherichia coli outer membrane.

    Science.gov (United States)

    Salazar, Javier; Alarcón, Mackarenna; Huerta, Jaime; Navarro, Belén; Aguayo, Daniel

    2017-04-15

    Phosphoethanolamine (pEtN) decoration of E. coli Lipopolysaccharide (LPS) provides resistance to the antimicrobial Polymyxin B (PolB). While EptA and EptB enzymes catalyze the addition of pEtN to the Lipid A and Kdo (pEtN-Kdo-Lipid A), EptC catalyzes the pEtN addition to the Heptose I (pEtN-HeptI). In this study, we investigated the contribution of pEtN-HeptI to PolB resistance using eptA/eptB and eptC deficient E. coli K12 and its wild-type parent strains. These mutations were shown to decrease the antimicrobial activity of PolB on cells grown under pEtN-addition inducing conditions. Furthermore, the 1-N-phenylnapthylamine uptake assay revealed that in vivo PolB has a reduced OM-permeabilizing activity on the ΔeptA/eptB strain compared with the ΔeptC strain. In vitro, the changes in size and zeta potential of LPS-vesicles indicate that pEtN-HeptI reduce the PolB binding, but in a minor extent than pEtN-Kdo-Lipid A. Molecular dynamics analysis revealed the structural basis of the PolB resistance promoted by pEtN-HeptI, which generate a new hydrogen-bonding networks and a denser inner core region. Altogether, the experimental and theoretical assays shown herein indicate that pEtN-HeptI addition promote an LPS conformational rearrangement, that could act as a shield by hindering the accession of PolB to inner LPS-targets moieties. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Short wavelength topography on the inner-core boundary.

    Science.gov (United States)

    Cao, Aimin; Masson, Yder; Romanowicz, Barbara

    2007-01-02

    Constraining the topography of the inner-core boundary is important for studies of core-mantle coupling and the generation of the geodynamo. We present evidence for significant temporal variability in the amplitude of the inner core reflected phase PKiKP for an exceptionally high-quality earthquake doublet, observed postcritically at the short-period Yellowknife seismic array (YK), which occurred in the South Sandwich Islands within a 10-year interval (1993/2003). This observation, complemented by data from several other doublets, indicates the presence of topography at the inner-core boundary, with a horizontal wavelength on the order of 10 km. Such topography could be sustained by small-scale convection at the top of the inner core and is compatible with a rate of super rotation of the inner core of approximately 0.1-0.15 degrees per year. In the absence of inner-core rotation, decadal scale temporal changes in the inner-core boundary topography would provide an upper bound on the viscosity at the top of the inner core.

  17. Electromagnetically driven westward drift and inner-core superrotation in Earth’s core

    Science.gov (United States)

    Livermore, Philip W.; Hollerbach, Rainer; Jackson, Andrew

    2013-01-01

    A 3D numerical model of the earth’s core with a viscosity two orders of magnitude lower than the state of the art suggests a link between the observed westward drift of the magnetic field and superrotation of the inner core. In our model, the axial electromagnetic torque has a dominant influence only at the surface and in the deepest reaches of the core, where it respectively drives a broad westward flow rising to an axisymmetric equatorial jet and imparts an eastward-directed torque on the solid inner core. Subtle changes in the structure of the internal magnetic field may alter not just the magnitude but the direction of these torques. This not only suggests that the quasi-oscillatory nature of inner-core superrotation [Tkalčić H, Young M, Bodin T, Ngo S, Sambridge M (2013) The shuffling rotation of the earth’s inner core revealed by earthquake doublets. Nat Geosci 6:497–502.] may be driven by decadal changes in the magnetic field, but further that historical periods in which the field exhibited eastward drift were contemporaneous with a westward inner-core rotation. The model further indicates a strong internal shear layer on the tangent cylinder that may be a source of torsional waves inside the core. PMID:24043841

  18. Electromagnetically driven westward drift and inner-core superrotation in Earth's core.

    Science.gov (United States)

    Livermore, Philip W; Hollerbach, Rainer; Jackson, Andrew

    2013-10-01

    A 3D numerical model of the earth's core with a viscosity two orders of magnitude lower than the state of the art suggests a link between the observed westward drift of the magnetic field and superrotation of the inner core. In our model, the axial electromagnetic torque has a dominant influence only at the surface and in the deepest reaches of the core, where it respectively drives a broad westward flow rising to an axisymmetric equatorial jet and imparts an eastward-directed torque on the solid inner core. Subtle changes in the structure of the internal magnetic field may alter not just the magnitude but the direction of these torques. This not only suggests that the quasi-oscillatory nature of inner-core superrotation [Tkalčić H, Young M, Bodin T, Ngo S, Sambridge M (2013) The shuffling rotation of the earth's inner core revealed by earthquake doublets. Nat Geosci 6:497-502.] may be driven by decadal changes in the magnetic field, but further that historical periods in which the field exhibited eastward drift were contemporaneous with a westward inner-core rotation. The model further indicates a strong internal shear layer on the tangent cylinder that may be a source of torsional waves inside the core.

  19. Inner-Most Inner Core: Distinct Region at the Center of the Earth

    Science.gov (United States)

    Ishii, M.; Dziewoński, A. M.

    2002-12-01

    Although the presence of anisotropy in the inner core is widely accepted, inferences of its strength and depth dependence vary considerably from model to model. We have recently shown that a significant fraction of inner-core sensitive (normal-mode and absolute/differential travel-time) data is reconciled by a model in which anisotropy does not vary with radius. This model predicts an almost linear dependence of travel-time residuals on cos2 ξ , where ξ is the angle between the ray path and the symmetry axis. The simple anisotropy model fits the absolute travel-time data well at all distance ranges except between 173° and 180°, where a strong dependence on (cos2 ξ )2 is observed. This distance range corresponds to the innermost 300~km of the Earth, where mode constraints are weak (because eigenfunctions must vanish at the center of the Earth), and where constraints from differential travel times ({ {PKP}} {AB}}-{ {PKP}}{ {DF}) are likely contaminated due to unmodelled mantle structure. We refer to this new region as the inner-most inner core. The (cos2 ξ )2 signal that indicates the existence of a distinct inner-most inner core is even more evident when effects due to anisotropy in the upper 920~km of the inner core are removed. Furthermore, division of the data into various subsets consistently reveals the anomalous dependence on (cos2 ξ )2, suggesting that it is a robust feature unique to this distance range. When the travel times are inverted for anisotropic parameters, we obtain a model with a slow direction orientered ~45° from the equator, in contrast to the bulk inner core where the slowest wave propagation occurs when the rays are parallel to the equatorial plane. The existence of the inner-most inner core has significant consequences in our understanding of the Earth's evolution. This region may represent fossil evidence of two episodes of inner core development or changes in the pattern of convection in the outer core. Furthermore, if the inner

  20. Influence of an inner core on the long-period forced librations of Mercury

    Science.gov (United States)

    Yseboodt, Marie; Rivoldini, Attilio; Van Hoolst, Tim; Dumberry, Mathieu

    2013-09-01

    The planetary perturbations on Mercury’s orbit lead to long-period forced librations of Mercury’s mantle. These librations have previously been studied for a planet with two layers: a mantle and a liquid core. Here, we calculate how the presence of a solid inner core in the liquid outer core influences the long-period forced librations. Mantle-inner core coupling affects the long-period libration dynamics mainly by changing the free libration: first, it lengthens the period of the free libration of the mantle, and second, it adds a second free libration, closely related to the free gravitational oscillation between the mantle and inner core. The two free librations have periods between 2.5 and 18y depending on the internal structure. We show that large amplitude long-period librations of a few tens of arcsec are generated when the period of a planetary forcing approaches one of the two free libration periods. These amplitudes are sufficiently large to be detectable by spacecraft measurements of the libration of Mercury. The amplitudes of the angular velocity of Mercury’s mantle at planetary forcing periods are also amplified by the resonances, but remain much smaller than the current precision of Earth-based radar observations unless the period is very close to a free libration period. The inclusion of mantle-inner core coupling in the rotation model does not significantly improve the fit to the radar observations. This implies that it is not yet possible to determine the size of the inner core of Mercury on the basis of available observations of Mercury’s rotation rate. Future observations of the long-period librations may be used to constrain the interior structure of Mercury, including the size of its inner core.

  1. Fine-scale heterogeneity in the Earth's inner core

    Science.gov (United States)

    Vidale; Earle

    2000-03-16

    The seismological properties of the Earth's inner core have become of particular interest as we understand more about its composition and thermal state. Observations of anisotropy and velocity heterogeneity in the inner core are beginning to reveal how it has grown and whether it convects. The attenuation of seismic waves in the inner core is strong, and studies of seismic body waves have found that this high attenuation is consistent with either scattering or intrinsic attenuation. The outermost portion of the inner core has been inferred to possess layering and to be less anisotropic than at greater depths. Here we present observations of seismic waves scattered in the inner core which follow the expected arrival time of the body-wave reflection from the inner-core boundary. The amplitude of these scattered waves can be explained by stiffness variations of 1.2% with a scale length of 2 kilometres across the outermost 300 km of the inner core. These variations might be caused by variations in composition, by pods of partial melt in a mostly solid matrix or by variations in the orientation or strength of seismic anisotropy.

  2. Seismic attenuation of the inner core: Viscoelastic or stratigraphic?

    Science.gov (United States)

    Cormier, V.F.; Xu, L.; Choy, G.L.

    1998-01-01

    Broadband velocity waveforms of PKIKP in the distance range 150??to 180??are inverted for inner core attenuation. A mean Q?? of 244 is determined at 1 Hz from 8 polar and 9 equatorial paths. The scatter in measured Q-1 exceeds individual error estimates, suggesting significant variation in attenuation with path. These results are interpreted by (1) viscoelasticity, in which the relaxation spectrum has a low-frequency corner near or slightly above the frequency band of short-period body waves, and by (2) stratigraphic (scattering) attenuation, in which attenuation and pulse broadening are caused by the interference of scattered multiples in a velocity structure having rapid fluctuations along a PKIKP path. In the scattering interpretation, PKIKP attenuation is only weakly affected by the intrinsic shear attenuation measured in the free-oscillation band. Instead, its frequency dependence, path variations, and fluctuations are all explained by scattering attenuation in a heterogeneous fabric resulting from solidification texturing of intrinsically anisotropic iron. The requisite fabric may consist of either single or ordered groups of crystals with P velocity differences of at least 5% and as much as 12% between two crystallographic axes at scale lengths of 0.5 to 2 km in the direction parallel to the axis of rotation and longer in the cylindrically radial direction, perpendicular to the axis of rotation.Broadband velocity waveforms of PKIKP in the distance range 150?? to 180?? are inverted for inner core attenuation. A mean Q?? of 244 is determined at 1 Hz from 8 polar and 9 equatorial paths. The scatter in the measured Q-1 exceeds individual error estimates, indicating significant variation in attenuation with path. The results are interpreted by viscoelasticity and stratigraphic (scattering) attenuation.

  3. Radial And Lateral Topographic Scales of the Inner-Core Boundary

    Science.gov (United States)

    Zheng, Y.; Cormier, V. F.; Fehler, M. C.

    2012-12-01

    Strong seismic evidence suggests that the inner core boundary region is dynamic. First, the strong PKP-df coda wave train in the previous time-lapse studies using earthquake doublets cannot be explained by simple rotation of the anisotropic inner core. Second, the observed PKiKP reflection amplitude from nuclear tests does not follow the prediction of a simple spherical model such as the PREM or IASP91. Third, observed amplitude and the traveltime of the PKP C-diff arrival favor different but inconsistent models (PREM-like linear gradient and IASP91-like no gradient, respectively) for the lowermost outer core. Fourth, we observed a seismic phase that had not been reported in the literature in the range of 150-153 degrees, which is about 2.0 seconds after the PKP-df and it has slightly positive slowness deviation compared to the PKIKP-df. Seismic migration showed that this arrival is associated with scattering objects above the turning depth of the PKIKP-df, close to the inner-core boundary. Using an elastic boundary element method, which takes into account of the fluid-solid boundary condition, we simulated high frequency (> 1 Hz) wave propagation and scattering in the inner core boundary region. We propose the presence of inner core topography as a plausible mechanism to explain all these observations. Our preliminary results by modeling the PKiKP amplitude showed that the previously proposed "mosaic structure" of the inner core could be well explained by inner core topography, with horizontal scale ~ 10km and vertical scale ~2km. In addition, for a fluid-solid boundary, topography can generate a strong Scholte wave, which is an interface wave (like the Rayleigh wave) whose amplitude decays exponentially away from the boundary. The Scholte wave can leak energy out of the C-diff wave therefore reducing the C-diff amplitude. Modeling the PKiKP, PKP-df coda and PKP C-diff allows us to place vertical and horizontal topographic bounds for the inner-core boundary.

  4. How Inge Lehmann Discovered the Inner Core of the Earth

    Science.gov (United States)

    Rousseau, Christiane

    2013-01-01

    The mathematics behind Inge Lehmann's discovery that the inner core of the Earth is solid is explained using data collected around the Earth on seismic waves and their travel time through the Earth.

  5. Rotation and magnetism of Earth`s inner core

    Energy Technology Data Exchange (ETDEWEB)

    Glatzmaier, G.A. [Los Alamos National Lab., NM (United States); Roberts, P.H. [Univ. of California, Los Angeles, CA (United States)

    1996-12-13

    Three-dimensional numerical simulations of the geodynamo suggest that a super-rotation of Earth`s solid inner core relative to the mantle is maintained by magnetic coupling between the inner core and an eastward thermal wind in the fluid outer core. This mechanism, which is analogous to a synchronous motor, also plays a fundamental role in the generation of Earth`s magnetic field. 18 refs., 6 figs.

  6. Precision-seismology studies of inner core rotation and seismotectonics using correlated earthquake signals

    Science.gov (United States)

    Zhang, Jian

    2007-12-01

    directions of ray path, lateral velocity gradient, and particle motion due to inner core super-rotation. For the Bucaramanga nest earthquakes, in the third chapter I have also achieved teleseismic high-precision relocation of the nest by applying a double-difference (DD) algorithm to phase picks from EHB bulletin of Engdahl et al. [1998] and waveform cross-correlation (WCC) measurements. The DD relocation of all Bucaramanga nest events reveals that about 700 events (˜ 70% of all events in the past 40 years) focus on a small fault-like volume that has dimensions of 20 km x 10 km x 10 km. A map view of the relocated seismicity shows an elongated structure striking at ˜ 135°. An on-fault view indicates an approximately 10 km thick band of seismicity, tilted at ˜ 40° to the SE. Further improvement of the pick-based DD relocation using WCC measurements on a set of 33 similar events images a complex near-vertical weak zone with a width of ˜ 5 km. Focal mechanisms of the nest earthquakes are highly variable. It may be that an intrinsic cause of the repeated (nest-type) activity, is indicated by the variability of focal mechanisms. However, the P axes generally align with the orientation of the relative plate movement between Nazca and Caribbean. I have proposed a slab-slab interaction model, in which the nest may represent a contact zone where two subducted slabs, belonging to the Nazca plate and the Caribbean plate respectively, collide and slide past each other.

  7. Detection of inner core solidification from observations of antipodal PKIIKP

    Science.gov (United States)

    Cormier, Vernon F.

    2015-09-01

    PKIIKP waves, reflected from the underside of the inner core boundary, are very sensitive to the S velocity in the uppermost 80 km of the inner core at antipodal distances, undergoing a phase change and a factor of 4 amplification as the distance approaches 180°. Modeled PKIIKP waveforms are consistent with a near-zero shear modulus in the uppermost inner core in a 20-40 km thick patch beneath the eastern equatorial hemisphere. This bright spot of PKIIKP reflection correlates with a thin zone of low P velocity inferred from the complexity of PKIKP waveforms sampling this patch. Estimates of grain sizes from seismic attenuation, the absence of backscattered PKiKP coda in this region, and a prediction for enhanced heat flow through this patch suggest that it is a region of solidification rather than melting.

  8. A convection model to explain anisotropy of the inner core

    Energy Technology Data Exchange (ETDEWEB)

    Wenk, H.-R. [Department of Geology and Geophysics, University of California, Berkeley (United States); Baumgardner, J. R. [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico (United States); Lebensohn, R. A. [CONICET, Consejo Nacional de Investigaciones Cientificas y Tecnicas, University of Rosario, Rosario, (Argentina); Tome, C. N. [Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, New Mexico (United States)

    2000-03-10

    Seismic evidence suggests that the solid inner core of the Earth may be anisotropic. Several models have been proposed to explain this anisotropy as the result of preferred orientation of crystals. They range from a large annealed single crystal, growth at the melt interface, to deformation-induced texture. In this study texture development by deformation during inner core convection is explored for {epsilon}-iron (hcp) and {gamma}-iron (fcc). Convection patterns for harmonic degree two were investigated in detail. In the model it is assumed that traces of potassium are uniformly dispersed in the inner core and act as a heat source. Both for fcc and hcp iron, crystal rotations associated with intracrystalline slip during deformation can plausibly explain a 1-3% anisotropy in P waves with faster velocities along the N-S axis and slower ones in the equatorial plane. The effect of single crystal elastic constants is explored. (c) 2000 American Geophysical Union.

  9. High-P,T Elasticity of Hcp Iron: Reinvestigation of the Applicability of Hcp Iron to the Earth's Inner Core

    Science.gov (United States)

    Tsuchiya, T.; Kawai, K.; Kuwayama, Y.; Ohsumi, M.; Ishii, M.

    2015-12-01

    Earth's inner core (329~364 GPa and 5000~6000 K) is thought to be composed of hexagonal closed pack (hcp) structured solid Fe-Ni alloy (e.g., Mao et al., 1998; Kuwayama et al., 2008; Sha & Cohen, 2010). Thermoelasticity of hcp (ɛ) iron is therefore a key to interpreting seismological information of the inner core: density, seismic wave velocities, and their anisotropy. However, several studies reported that hcp iron has a shear modulus distinctly larger than that of the inner core (e.g., Mao et al., 1998; Vocadlo et al., 2009). This large Poisson ratio of the inner core is one of the remaining inexplicable features of the deep Earth, and it suggests the presence of mechanisms to lower the S-wave velocity in the inner core, such as a low-velocity component (Prescher et al., 2015), pre-melting effect (Martorell et al., 2013), anelasticity, and so on. In this study, we perform ab initio molecular dynamics simulations employing a supercell larger than in previous calculations (Vocadlo et al., 2009; Martorell et al., 2013). Also computations are conducted in a wide P,T range including, but not limited to, the inner core conditions to clarify the P,T effects on the elasticity of the hcp iron more comprehensively, and to provide an internally-consistent thermoelastic model. In addition to checking the validity of the Birch's law, the obtained Poisson ratio and aggregate anisotropy, with and without the pre-melting effect, are compared against seismological constraints to reinvestigate the viability of hcp iron in the inner core. Research supported by KAKENHI (JSPS) and the X-ray Free Electron Laser Priority Strategy Program (MEXT).

  10. Spatial structure of directional wave spectra in hurricanes

    Science.gov (United States)

    Esquivel-Trava, Bernardo; Ocampo-Torres, Francisco J.; Osuna, Pedro

    2015-01-01

    The spatial structure of the wave field during hurricane conditions is studied using the National Data Buoy Center directional wave buoy data set from the Caribbean Sea and the Gulf of Mexico. The buoy information, comprising the directional wave spectra during the passage of several hurricanes, was referenced to the center of the hurricane using the path of the hurricane, the propagation velocity, and the radius of the maximum winds. The directional wave spectra were partitioned into their main components to quantify the energy corresponding to the observed wave systems and to distinguish between wind-sea and swell. The findings are consistent with those found using remote sensing data (e.g., Scanning Radar Altimeter data). Based on the previous work, the highest waves are found in the right forward quadrant of the hurricane, where the spectral shape tends to become uni-modal, in the vicinity of the region of maximum winds. More complex spectral shapes are observed in distant regions at the front of and in the rear quadrants of the hurricane, where there is a tendency of the spectra to become bi- and tri-modal. The dominant waves generally propagate at significant angles to the wind direction, except in the regions next to the maximum winds of the right quadrants. Evidence of waves generated by concentric eyewalls associated with secondary maximum winds was also found. The frequency spectra display some of the characteristics of the JONSWAP spectrum adjusted by Young (J Geophys Res 111:8020, 2006); however, at the spectral peak, the similarity with the Pierson-Moskowitz spectrum is clear. These results establish the basis for the use in assessing the ability of numerical models to simulate the wave field in hurricanes.

  11. Stability of body-centered cubic iron-magnesium alloys in the Earth's inner core.

    Science.gov (United States)

    Kádas, Krisztina; Vitos, Levente; Johansson, Börje; Ahuja, Rajeev

    2009-09-15

    The composition and the structure of the Earth's solid inner core are still unknown. Iron is accepted to be the main component of the core. Lately, the body-centered cubic (bcc) phase of iron was suggested to be present in the inner core, although its stability at core conditions is still in discussion. The higher density of pure iron compared with that of the Earth's core indicates the presence of light element(s) in this region, which could be responsible for the stability of the bcc phase. However, so far, none of the proposed composition models were in full agreement with seismic observations. The solubility of magnesium in hexagonal Fe has been found to increase significantly with increasing pressure, suggesting that Mg can also be an important element in the core. Here, we report a first-principles density functional study of bcc Fe-Mg alloys at core pressures and temperatures. We show that at core conditions, 5-10 atomic percent Mg stabilizes the bcc Fe both dynamically and thermodynamically. Our calculated density, elastic moduli, and sound velocities of bcc Fe-Mg alloys are consistent with those obtained from seismology, indicating that the bcc-structured Fe-Mg alloy is a possible model for the Earth's inner core.

  12. Influence of an inner core on the long-period forced librations of Mercury

    CERN Document Server

    Yseboodt, Marie; Van Hoolst, Tim; Dumberry, Mathieu

    2013-01-01

    The planetary perturbations on Mercury's orbit lead to long-period forced librations of Mercury's mantle. These librations have previously been studied for a planet with two layers: a mantle and a liquid core. Here, we calculate how the presence of a solid inner core in the liquid outer core influences the long-period forced librations. Mantle-inner core coupling affects the long-period libration dynamics mainly by changing the free libration: first, it lengthens the period of the free libration of the mantle, and second, it adds a second free libration, closely related to the free gravitational oscillation between the mantle and inner core. The two free librations have periods between 2.5 and 18 y depending on the internal structure. We show that large amplitude long-period librations of 10's of arcsec are generated when the period of a planetary forcing approaches one of the two free libration periods. These amplitudes are sufficiently large to be detectable by spacecraft measurements of the libration of Me...

  13. Hurricane impacts on a pair of coastal forested watersheds: implications of selective hurricane damage to forest structure and streamflow dynamics

    Directory of Open Access Journals (Sweden)

    A. D. Jayakaran

    2013-09-01

    Full Text Available Hurricanes are infrequent but influential disruptors of ecosystem processes in the southeastern Atlantic and Gulf coasts. Every southeastern forested wetland has the potential to be struck by a tropical cyclone. We examined the impact of Hurricane Hugo on two paired coastal watersheds in South Carolina in terms of stream flow and vegetation dynamics, both before and after the hurricane's passage in 1989. The study objectives were to quantify the magnitude and timing of changes including a reversal in relative streamflow-difference between two paired watersheds, and to examine the selective impacts of a hurricane on the vegetative composition of the forest. We related these impacts to their potential contribution to change watershed hydrology through altered evapotranspiration processes. Using over thirty years of monthly rainfall and streamflow data we showed that there was a significant transformation in the hydrologic character of the two watersheds – a transformation that occurred soon after the hurricane's passage. We linked the change in the rainfall-runoff relationship to a catastrophic shift in forest vegetation due to selective hurricane damage. While both watersheds were located in the path of the hurricane, extant forest structure varied between the two watersheds as a function of experimental forest management techniques on the treatment watershed. We showed that the primary damage was to older pines, and to some extent larger hardwood trees. We believe that lowered vegetative water use impacted both watersheds with increased outflows on both watersheds due to loss of trees following hurricane impact. However, one watershed was able to recover to pre hurricane levels of canopy transpiration at a quicker rate due to the greater abundance of pine seedlings and saplings in that watershed.

  14. Planet Within a Planet: Rotation of the Inner Core of Earth

    Science.gov (United States)

    Su; Dziewonski; Jeanloz

    1996-12-13

    The time dependence of the orientation of Earth's inner core relative to the mantle was determined using a recently discovered 10-degree tilt in the axis of symmetry of the inner core's seismic-velocity anisotropy. Two methods of analyzing travel-time variations for rays traversing the inner core, on the basis of 29 years of data from the International Seismological Centre (1964-1992), reveal that the inner core appears to rotate about 3 degrees per year faster than the mantle. An anomalous variation in inner-core orientation from 1969 to 1973 coincides in time with a sudden change ("jerk") in the geomagnetic field.

  15. Palaeointensity, core thermal conductivity and the unknown age of the inner core

    Science.gov (United States)

    Smirnov, Aleksey V.; Tarduno, John A.; Kulakov, Evgeniy V.; McEnroe, Suzanne A.; Bono, Richard K.

    2016-05-01

    Data on the evolution of Earth's magnetic field intensity are important for understanding the geodynamo and planetary evolution. However, the paleomagnetic record in rocks may be adversely affected by many physical processes, which must be taken into account when analysing the palaeointensity database. This is especially important in the light of an ongoing debate regarding core thermal conductivity values, and how these relate to the Precambrian geodynamo. Here, we demonstrate that several data sets in the Precambrian palaeointensity database overestimate the true paleofield strength due to the presence of non-ideal carriers of palaeointensity signals and/or viscous re-magnetizations. When the palaeointensity overestimates are removed, the Precambrian database does not indicate a robust change in geomagnetic field intensity during the Mesoproterozoic. These findings call into question the recent claim that the solid inner core formed in the Mesoproterozoic, hence constraining the thermal conductivity in the core to `moderate' values. Instead, our analyses indicate that the presently available palaeointensity data are insufficient in number and quality to constrain the timing of solid inner core formation, or the outstanding problem of core thermal conductivity. Very young or very old inner core ages (and attendant high or low core thermal conductivity values) are consistent with the presently known history of Earth's field strength. More promising available data sets that reflect long-term core structure are geomagnetic reversal rate and field morphology. The latter suggests changes that may reflect differences in Archean to Proterozoic core stratification, whereas the former suggest an interval of geodynamo hyperactivity at ca. 550 Ma.

  16. On observation of local strong heterogeneity in the Earth's inner core below southeastern Asia

    Science.gov (United States)

    Krasnoshchekov, D. N.; Kaazik, P. B.; Ovtchinnikov, V. M.

    2016-12-01

    The dimensions and nature of multi-scale structural heterogeneities in the Earth's inner core (IC) provide important constraints on its mineralogy and formation history. Teleseismic body waves with turn points close to the inner core boundary (ICB) provide a unique tool for imaging the fine structure of the upper IC. In this study, we invoke differential travel times and amplitudes of PKPBC and PKPDF waveforms observed in crossing polar and equatorial paths to provide more constraints on the heterogeneity previously located in the quasi-eastern hemisphere of the IC (Kaazik et al., 2015; Krasnoshchekov et al., 2016). A more refined analysis of quasi-polar PKPBC/PKPDF amplitude ratios measured within the heterogeneity indicates that seismic attenuation is both frequency and depth dependent, and its relatively low Q-factor at 1 Hz of approximately 118 tends to grow with depth. Outside the heterogeneity, no pronounced polar-equatorial differences are observed; the estimated Q factor is about twice as large and not directionally dependent. We also analyse new differential travel times of rays that enable sampling of the anomaly at greater depths. The analysis exhibits the polar - equatorial contrasts observed in the heterogeneity terminate at approximately 520 km below the ICB, which we interpret to be its bottom. The earlier interpretation of the heterogeneity in terms of strong anisotropic volume amidst the almost isotropic eastern hemisphere of the IC can be retained, and the lower bound of anisotropy strength within the anomaly is determined to be 2%.

  17. Shear softening of Earth's inner core indicated by its high Poisson's ratio and elastic anisotropy

    CERN Document Server

    Wu, Zhongqing

    2016-01-01

    Earth's inner core exhibits an unusually high Poisson's ratio and noticeable elastic anisotropy. The mechanisms responsible for these features are critical for understanding the evolution of the Earth but remain unclear. This study indicates that once the correct formula for the shear modulus is used, shear softening can simultaneously explain the high Poisson's ratio and strong anisotropy of the inner core. Body-centred-cubic (bcc) iron shows shear instability at the pressures found in the inner-core and can be dynamically stabilized by temperature and light elements. It is very likely that some combinations of light elements stabilize the bcc iron alloy under inner-core conditions. Such a bcc phase would exhibit significant shear softening and match the geophysical constraints of the inner core. Identifying which light elements and what concentrations of these elements stabilize the bcc phase will provide critical information on the light elements of the inner core.

  18. Estimated Drag Coefficients and Wind Structure of Hurricane Frances

    Science.gov (United States)

    Zedler, S. E.; Niiler, P. P.; Stammer, D.; Terrill, E.

    2006-12-01

    As part of the Coupled Boundary Layers Air Sea Transfer (CBLAST) experiment, an array of drifters and floats was deployed from an aircraft just ahead of Hurricane Frances during it's passage to the northwest side of the Caribbean Island chain in August, 2004. The ocean and surface air conditions prior to, during, and after Hurricane Frances were documented by multiple sensors. Two independent estimates of the surface wind field suggest different storm structures. NOAA H*WINDS, an objectively analyzed product using a combination of data collected at the reconnaissance flight level, GPS profilers (dropwindsondes), satellites, and other data, suggest a 40km radius of maximum wind. A product based on the radial momentum equation balance using \\ital{in-situ} surface pressure data and wind direction measurements from the CBLAST drifter array suggests that the radius of maximum winds was 15km. We used a regional version of the MITGCM model with closed boundaries and realistic temperature and salinity fields which was forced with these wind field products to determine which wind field leads to circulation and SST structures that are most consistent with observed sea surface temperature fields and float profile data. Best estimates of the surface wind structure are then used to estimate the appropriate drag coefficient corresponding to the maximum velocity. Our results are compared with those obtained previously.

  19. Reactions of xenon with iron and nickel are predicted in the Earth's inner core.

    Science.gov (United States)

    Zhu, Li; Liu, Hanyu; Pickard, Chris J; Zou, Guangtian; Ma, Yanming

    2014-07-01

    Studies of the Earth's atmosphere have shown that more than 90% of the expected amount of Xe is depleted, a finding often referred to as the 'missing Xe paradox'. Although several models for a Xe reservoir have been proposed, whether the missing Xe could be contained in the Earth's inner core has not yet been answered. The key to addressing this issue lies in the reactivity of Xe with Fe/Ni, the main constituents of the Earth's core. Here, we predict, through first-principles calculations and unbiased structure searching techniques, a chemical reaction of Xe with Fe/Ni at the temperatures and pressures found in the Earth's core. We find that, under these conditions, Xe and Fe/Ni can form intermetallic compounds, of which XeFe3 and XeNi3 are energetically the most stable. This shows that the Earth's inner core is a natural reservoir for Xe storage and provides a solution to the missing Xe paradox.

  20. Family Structures, Relationships, and Housing Recovery Decisions after Hurricane Sandy

    Directory of Open Access Journals (Sweden)

    Ali Nejat

    2016-04-01

    Full Text Available Understanding of the recovery phase of a disaster cycle is still in its infancy. Recent major disasters such as Hurricane Sandy have revealed the inability of existing policies and planning to promptly restore infrastructure, residential properties, and commercial activities in affected communities. In this setting, a thorough grasp of housing recovery decisions can lead to effective post-disaster planning by policyholders and public officials. The objective of this research is to integrate vignette and survey design to study how family bonds affected rebuilding/relocating decisions after Hurricane Sandy. Multinomial logistic regression was used to investigate respondents’ family structures before Sandy and explore whether their relationships with family members changed after Sandy. The study also explores the effect of the aforementioned relationship and its changes on households’ plans to either rebuild/repair their homes or relocate. These results were compared to another multinomial logistic regression which was applied to examine the impact of familial bonds on respondents’ suggestions to a vignette family concerning rebuilding and relocating after a hurricane similar to Sandy. Results indicate that respondents who lived with family members before Sandy were less likely to plan for relocating than those who lived alone. A more detailed examination shows that this effect was driven by those who improved their relationships with family members; those who did not improve their family relationships were not significantly different from those who lived alone, when it came to rebuilding/relocation planning. Those who improved their relationships with family members were also less likely to suggest that the vignette family relocate. This study supports the general hypothesis that family bonds reduce the desire to relocate, and provides empirical evidence that family mechanisms are important for the rebuilding/relocating decision

  1. Irregular topography at the Earth’s inner core boundary

    Science.gov (United States)

    Dai, Zhiyang; Wang, Wei; Wen, Lianxing

    2012-01-01

    Compressional seismic wave reflected off the Earth’s inner core boundary (ICB) from earthquakes occurring in the Banda Sea and recorded at the Hi-net stations in Japan exhibits significant variations in travel time (from -2 to 2.5 s) and amplitude (with a factor of more than 4) across the seismic array. Such variations indicate that Earth’s ICB is irregular, with a combination of at least two scales of topography: a height variation of 14 km changing within a lateral distance of no more than 6 km, and a height variation of 4–8 km with a lateral length scale of 2–4 km. The characteristics of the ICB topography indicate that small-scale variations of temperature and/or core composition exist near the ICB, and/or the ICB topographic surface is being deformed by small-scale forces out of its thermocompositional equilibrium position and is metastable. PMID:22547788

  2. Irregular topography at the Earth's inner core boundary.

    Science.gov (United States)

    Dai, Zhiyang; Wang, Wei; Wen, Lianxing

    2012-05-15

    Compressional seismic wave reflected off the Earth's inner core boundary (ICB) from earthquakes occurring in the Banda Sea and recorded at the Hi-net stations in Japan exhibits significant variations in travel time (from -2 to 2.5 s) and amplitude (with a factor of more than 4) across the seismic array. Such variations indicate that Earth's ICB is irregular, with a combination of at least two scales of topography: a height variation of 14 km changing within a lateral distance of no more than 6 km, and a height variation of 4-8 km with a lateral length scale of 2-4 km. The characteristics of the ICB topography indicate that small-scale variations of temperature and/or core composition exist near the ICB, and/or the ICB topographic surface is being deformed by small-scale forces out of its thermocompositional equilibrium position and is metastable.

  3. Complex inner core of the Earth: The last frontier of global seismology

    Science.gov (United States)

    Tkalčić, Hrvoje

    2015-03-01

    The days when the Earth's inner core (IC) was viewed as a homogeneous solid sphere surrounded by the liquid outer core (OC) are now behind us. Due to a limited number of data sampling the IC and a lack of experimentally controlled conditions in the deep Earth studies, it has been difficult to scrutinize competitive hypotheses in this active area of research. However, a number of new concepts linking IC structure and dynamics has been proposed lately to explain different types of seismological observations. A common denominator of recent observational work on the IC is increased complexity seen in IC physical properties such as its isotropic and anisotropic structure, attenuation, inner core boundary (ICB) topography, and its rotational dynamics. For example, small-scale features have been observed to exist as a widespread phenomenon in the uppermost inner core, probably superimposed on much longer-scale features. The characterization of small-scale features sheds light on the nature of the solidification process and helps in understanding seismologically observed hemispherical dichotomy of the IC. The existence of variations in the rate and level of solidification is a plausible physical outcome in an environment where vigorous compositional convection in the OC and variations in heat exchange across the ICB may control the process of crystal growth. However, further progress is hindered by the fact that the current traveltime data of PKIKP waves traversing the IC do not allow discriminating between variations in isotropic P wave velocity and velocity anisotropy. Future studies of attenuation in the IC might provide crucial information about IC structure, although another trade-off exists—that of the relative contribution of scattering versus viscoelastic attenuation and the connection with the material properties. Future installations of dense arrays, cross paths of waves that sample the IC, and corresponding array studies will be a powerful tool to image and

  4. Seismological evidence for a localized mushy zone at the Earth's inner core boundary.

    Science.gov (United States)

    Tian, Dongdong; Wen, Lianxing

    2017-08-01

    Although existence of a mushy zone in the Earth's inner core has been hypothesized several decades ago, no seismic evidence has ever been reported. Based on waveform modeling of seismic compressional waves that are reflected off the Earth's inner core boundary, here we present seismic evidence for a localized 4-8 km thick zone across the inner core boundary beneath southwest Okhotsk Sea with seismic properties intermediate between those of the inner and outer core and of a mushy zone. Such a localized mushy zone is found to be surrounded by a sharp inner core boundary nearby. These seismic results suggest that, in the current thermo-compositional state of the Earth's core, the outer core composition is close to eutectic in most regions resulting in a sharp inner core boundary, but deviation from the eutectic composition exists in some localized regions resulting in a mushy zone with a thickness of 4-8 km.The existence of a mushy zone in the Earth's inner core has been suggested, but has remained unproven. Here, the authors have discovered a 4-8 km thick mushy zone at the inner core boundary beneath the Okhotsk Sea, indicating that there may be more localized mushy zones at the inner core boundary.

  5. Hypothesis of Piezoelectricity of Inner Core As the Origin of Geomagnetism

    Directory of Open Access Journals (Sweden)

    Y Hayakawa

    2009-06-01

    Full Text Available A novel hypothesis is proposed that assumes piezoelectricity of the inner core as the origin of geomagnetism. By high pressure, electric charge is created on the surface and at the center of the earth. Inner core rotation yields a magnetic field. From the intensity and direction of geomagnetism at the present time, the surface charge density of the inner core is assumed to be -2x10-5C/m2. The rotation axis of the inner core is inclined by 10.4 degrees from that of the mantle. The inner core rotates with the mantle rotation. The reason for this is thought to be the eddy currents induced in the outer core of electrically conductive fluid that rotates with the mantle.

  6. Slow Differential Inner-core Rotation Inferred From Changes In Scattering Over Time

    Science.gov (United States)

    Xu, F.; Vidale, J.; Dodge, D.; Earle, P.

    2001-12-01

    Due to its important implications for our understanding of the core processes, including the generation and reversal of the Earth's magnetic field, the possibility that the inner core may be rotating faster than the mantle has been of wide interest. Attempts to constrain the speed of this differential rotation with differential times of core phases and spatial migration of inner core heterogeneity have yielded various discordant results. The detection of scattering in the inner core has enabled us to conduct a simple test for inner core motion. We compared scattered waves recorded at LASA in Montana from two nuclear tests at Novaya Zemlya in 1971 and 1974. This nearly co-located pair of events offered a rare opportunity of interpreting the variation in the inner core scattered waves in terms of relative inner-core rotation. The coda indeed shows small but coherent changes. The observation of earlier scattered arrivals from the west in 1974 compared to 1971, and later scattered arrivals from the east indicated an inner-core rotation rate of 0.15o per year (Vidale et al, Nature, 2000). This rate falls within the bounds set by other measurements, some of which find an upper limit of 0.1 to 0.2 per year for inner-core differential rotation. This year, we present further details of the comparison of 1971 and 1974 Novaya Zemlya explosions, and compare 1971 and 1973 Aleutian explosions. The latter pair is more difficult to use to constrain inner core rotation because the blasts were 10 km apart, rather than less than 1 km in the former case.

  7. Hurricane-driven alteration in plankton community size structure in the Gulf of Mexico: A modeling study

    Science.gov (United States)

    Gierach, Michelle M.; Subrahmanyam, Bulusu; Samuelsen, Annette; Ueyoshi, Kyozo

    2009-04-01

    This was the first study to analyze phytoplankton and zooplankton community size structure during hurricane passage. A three-dimensional biophysical model was used to assess ecosystem dynamics, plankton biomass, and plankton distribution in the Gulf of Mexico during Hurricane Katrina (2005). Model simulations revealed that large phytoplankton were most responsive to hurricane-induced turbulent mixing and nutrient injection, with increases in biomass along the hurricane track. Small phytoplankton, microzooplankton, and mesozooplankton biomass primarily shifted in location and increased in spatial extent as a result of Hurricane Katrina. Hurricane passage disrupted the distribution of plankton biomass associated with mesoscale eddies. Biomass minimums and maximums that resided in the center of warm- and cold-core eddies and along eddy peripheries prior to hurricane passage were displaced during Hurricane Katrina.

  8. Implication of the lopsided growth for the viscosity of Earth's inner core

    CERN Document Server

    Mizzon, Hugau

    2012-01-01

    Two main seismic features characterize the Earth's inner core: a North-South polar anisotropy and an East-West asymmetry of P-wave velocity and attenuation. Anisotropy is expected if shear deformation is induced by convective motions. Translation has recently been put forward as an important mode of convection of the inner core. Combined with a simple diffusive grain growth model, this mechanism is able to explain the observed seismic asymmetry, but not the bulk anisotropy. The source of anisotropy has therefore to be sought in the shear motions caused by higher modes of convection. Using a hybrid finite-difference spherical harmonics Navier-Stokes solver, we investigate the interplay between translation and convection in a 3D spherical model with permeable boundary conditions at the inner core boundary. Three parameters act independently: viscosity, internal heating and convection velocity in the outer core. Our numerical simulations show the dominance of pure translation for viscosities of the inner core hi...

  9. Infrasonic ray tracing applied to mesoscale atmospheric structures: refraction by hurricanes.

    Science.gov (United States)

    Bedard, Alfred J; Jones, R Michael

    2013-11-01

    A ray-tracing program is used to estimate the refraction of infrasound by the temperature structure of the atmosphere and by hurricanes represented by a Rankine-combined vortex wind plus a temperature perturbation. Refraction by the hurricane winds is significant, giving rise to regions of focusing, defocusing, and virtual sources. The refraction of infrasound by the temperature anomaly associated with a hurricane is small, probably no larger than that from uncertainties in the wind field. The results are pertinent to interpreting ocean wave generated infrasound in the vicinities of tropical cyclones.

  10. Implication of the lopsided growth for the viscosity of Earth's inner core

    OpenAIRE

    Mizzon, Hugau; Monnereau, Marc

    2012-01-01

    Two main seismic features characterize the Earth's inner core: a North-South polar anisotropy and an East-West asymmetry of P-wave velocity and attenuation. Anisotropy is expected if shear deformation is induced by convective motions. Translation has recently been put forward as an important mode of convection of the inner core. Combined with a simple diffusive grain growth model, this mechanism is able to explain the observed seismic asymmetry, but not the bulk anisotropy. The source of anis...

  11. Thermal convection in Earth's inner core with phase change at its boundary

    CERN Document Server

    Deguen, Renaud; Cardin, Philippe

    2013-01-01

    Inner core translation, with solidification on one hemisphere and melting on the other, provides a promising basis for understanding the hemispherical dichotomy of the inner core, as well as the anomalous stable layer observed at the base of the outer core - the F-layer - which might be sustained by continuous melting of inner core material. In this paper, we study in details the dynamics of inner core thermal convection when dynamically induced melting and freezing of the inner core boundary (ICB) are taken into account. If the inner core is unstably stratified, linear stability analysis and numerical simulations consistently show that the translation mode dominates only if the viscosity $\\eta$ is large enough, with a critical viscosity value, of order $3 10^{18}$ Pas, depending on the ability of outer core convection to supply or remove the latent heat of melting or solidification. If $\\eta$ is smaller, the dynamical effect of melting and freezing is small. Convection takes a more classical form, with a one...

  12. First-order theory for Earth’s inner-core anisotropy due to super-rotation and Ramachandran interaction

    Indian Academy of Sciences (India)

    Andrew Das Arulsamy

    2015-06-01

    Solidification mechanism at the Lehmann (inner core) boundary are postulated on the basis of Ramachandran interaction by taking the fluctuating inner core super-rotation into account. The postulates are found to be consistent with compressional or P-wave velocity obtained from seismic data analysis. We justify these postulates to be physically sound and precise, and show that the fluctuating inner core super-rotation causes significant changes to the strength of Fe–Fe Ramachandran interaction, which then leads to the observed asymmetric and anisotropic inner core. Our postulates also reliably explain that the depth-dependent anisotropic P-wave attenuation close to inner core surface (to about 100 km deep) is due to phonon excitation probability and different atomic orientation. We also discuss the consistency of our postulates with respect to asymmetric inner core anisotropy (between western and eastern inner core hemispheres).

  13. Dynamics of axial torsional libration under the mantle-inner core gravitational interaction

    Science.gov (United States)

    Chao, B. F.

    2017-01-01

    The aims of this paper are (i) formulating the dynamics of the mantle-inner core gravitational (MICG) interaction in terms of the spherical-harmonic multipoles of mass density. The modeled MICG system is composed of two concentric rigid bodies (mantle and inner core) of near-spherical but otherwise heterogeneous configuration, with a fluid outer core in between playing a passive role. We derive the general equation of motion for the vector rotation but only focus on the polar component that describes the MICG axial torsional libration. The torsion constant and hence the square of the natural frequency of the libration is proportional to the product of the equatorial ellipticities of the mantle and inner-core geoid embodied in their multipoles (of two different types) of degree 2 and order 2 (such as the Large Low-Shear-Velocity Provinces above the core-mantle boundary) and (ii) studying the geophysical implications upon equating the said MICG libration to the steady 6 year oscillation that are observed in the Earth's spin rate or the length-of-day variation (ΔLOD). In particular, the MICG torsion constant is found to be Γ>˜z = CIC σz2 ≈ 6.5 × 1019 N m, while the inner core's (BIC - AIC) ≈ 1.08 × 1031 kg m2 gives the inner core triaxiality (BIC - AIC)/CIC ≈ 1.8 × 10-4, about 8 times the whole-Earth value. It is also asserted that the required inner-core ellipticity amounts to no more than 140 m in geoid height, much smaller than the sensitivity required for the seismic wave travel time to resolve the variation of the inner core.

  14. Melting-induced stratification above the Earth's inner core due to convective translation.

    Science.gov (United States)

    Alboussière, Thierry; Deguen, Renaud; Melzani, Mickaël

    2010-08-05

    In addition to its global North-South anisotropy, there are two other enigmatic seismological observations related to the Earth's inner core: asymmetry between its eastern and western hemispheres and the presence of a layer of reduced seismic velocity at the base of the outer core. This 250-km-thick layer has been interpreted as a stably stratified region of reduced composition in light elements. Here we show that this layer can be generated by simultaneous crystallization and melting at the surface of the inner core, and that a translational mode of thermal convection in the inner core can produce enough melting and crystallization on each hemisphere respectively for the dense layer to develop. The dynamical model we propose introduces a clear asymmetry between a melting and a crystallizing hemisphere which forms a basis for also explaining the East-West asymmetry. The present translation rate is found to be typically 100 million years for the inner core to be entirely renewed, which is one to two orders of magnitude faster than the growth rate of the inner core's radius. The resulting strong asymmetry of buoyancy flux caused by light elements is anticipated to have an impact on the dynamics of the outer core and on the geodynamo.

  15. Changes in microbial community structure in the wake of Hurricanes Katrina and Rita.

    Science.gov (United States)

    Amaral-Zettler, Linda A; Rocca, Jennifer D; Lamontagne, Michael G; Dennett, Mark R; Gast, Rebecca J

    2008-12-15

    Hurricanes have the potential to alter the structures of coastal ecosystems and generate pathogen-laden floodwaters thatthreaten public health. To examine the impact of hurricanes on urban systems, we compared microbial community structures in samples collected after Hurricane Katrina and before and after Hurricane Rita. We extracted environmental DNA and sequenced small-subunit rRNA (SSU rRNA) gene clone libraries to survey microbial communities in floodwater, water, and sediment samples collected from Lake Charles, Lake Pontchartrain, the 17th Street and Industrial Canals in New Orleans, and raw sewage. Correspondence analysis showed that microbial communities associated with sediments formed one cluster while communities associated with lake and Industrial Canal water formed a second. Communities associated with water from the 17th Street Canal and floodwaters collected in New Orleans showed similarity to communities in raw sewage and contained a number of sequences associated with possible pathogenic microbes. This suggests that a distinct microbial community developed in floodwaters following Hurricane Katrina and that microbial community structures as a whole might be sensitive indicators of ecosystem health and serve as "sentinels" of water quality in the environment.

  16. Inner Core Anisotropy Due to the Magnetic Field--induced Preferred Orientation of Iron.

    Science.gov (United States)

    Karato, S

    1993-12-10

    Anisotropy of the inner core of the Earth is proposed to result from the lattice preferred orientation of anisotropic iron crystals during their solidification in the presence of a magnetic field. The resultant seismic anisotropy is related to the geometry of the magnetic field in the core. This hypothesis implies that the observed anisotropy (fast velocity along the rotation axis) indicates a strong toroidal field in the core, which supports a strong field model for the geodynamo if the inner core is made of hexagonal close-packed iron.

  17. Growth of the inner core in the mean-field dynamo model

    CERN Document Server

    Reshetnyak, M Yu

    2016-01-01

    Application of Parker's dynamo model to the geodynamo with the growing inner core is considered. It is shown that decrease of the inner core size, where intensive magnetic field generation takes place, leads to the multi-polar magnetic field in the past. This effect reflects the decrease of the region of the effective magnetic field generation. The process is accompanied by increase of the reversals number and decrease of intensity of the geomagnetic field. The constraints on the mechanisms of convection in the liquid core are discussed.

  18. Hurricane impacts on a pair of coastal forested watersheds: implications of selective hurricane damage to forest structure and streamflow dynamics

    Science.gov (United States)

    A.D. Jayakaran; T.M. Williams; H. Ssegane; D.M. Amatya; B. Song; C.C. Trettin

    2014-01-01

    Hurricanes are infrequent but influential disruptors of ecosystem processes in the southeastern Atlantic and Gulf coasts. Every southeastern forested wetland has the potential to be struck by a tropical cyclone. We examined the impact of Hurricane Hugo on two paired coastal South Carolina watersheds in terms of streamflow and vegetation dynamics, both before and after...

  19. The elastic properties and stability of fcc-Fe and fcc-FeNi alloys at inner-core conditions

    Science.gov (United States)

    Martorell, Benjamí; Brodholt, John; Wood, Ian G.; Vočadlo, Lidunka

    2015-07-01

    The agreement between shear wave velocities for the Earth's inner core observed from seismology with those derived from mineral physics is considerably worse than for any other region of the Earth. Furthermore, there is still debate as to the phase of iron present in the inner core, particularly when alloying with nickel and light elements is taken into account. To investigate the extent to which the mismatch between seismology and mineral physics is a function of either crystal structure and/or the amount of nickel present, we have used ab initio molecular dynamics simulations to calculate the elastic constants and seismic velocities (Vp and Vs) of face centred cubic (fcc) iron at Earth's inner core pressures (360 GPa) and at temperatures up to ˜7000 K. We find that Vp for fcc iron (fcc-Fe) is very similar to that for hexagonal close packed (hcp) iron at all temperatures. In contrast, Vs for fcc-Fe is significantly higher than in hcp-Fe, with the difference increasing with increasing temperature; the difference between Vs for the core (from seismology) and Vs for fcc-Fe exceeds 40 per cent. These results are consistent with previous work at lower temperatures. We have also investigated the effect of 6.5 and 13 atm% Ni in fcc-Fe. We find that Ni only slightly reduces Vp and Vs (e.g. by 2 per cent in Vs for 13 atm% Ni at 5500 K), and cannot account for the difference between the velocities observed in the core and those of pure fcc-Fe. We also tried to examine pre-melting behaviour in fcc-Fe, as reported in hcp-Fe by extending the study to very high temperatures (at which superheating may occur). However, we find that fcc-Fe spontaneously transforms to other hcp-like structures before melting; two hcp-like structures were found, both of hexagonal symmetry, which may most easily be regarded as being derived from an hcp crystal with stacking faults. That the structure did not transform to a true hcp phase is likely as a consequence of the limited size of the

  20. Melting-induced stratification above the Earth's inner core due to convective translation

    CERN Document Server

    Alboussiere, Thierry; Melzani, Mickael; 10.1038/nature09257

    2012-01-01

    In addition to its global North-South anisotropy(1), there are two other enigmatic seismological observations related to the Earth's inner core: asymmetry between its eastern and western hemispheres(2-6) and the presence of a layer of reduced seismic velocity at the base of the outer core(6-12). This 250-km-thick layer has been interpreted as a stably stratified region of reduced composition in light elements(13). Here we show that this layer can be generated by simultaneous crystallization and melting at the surface of the inner core, and that a translational mode of thermal convection in the inner core can produce enough melting and crystallization on each hemisphere respectively for the dense layer to develop. The dynamical model we propose introduces a clear asymmetry between a melting and a crystallizing hemisphere which forms a basis for also explaining the East-West asymmetry. The present translation rate is found to be typically 100 million years for the inner core to be entirely renewed, which is one...

  1. Anisotropy of Earth's inner core intrinsic attenuation from seismic normal mode models

    NARCIS (Netherlands)

    Mäkinen, Anna M.; Deuss, Arwen; Redfern, Simon A T

    2014-01-01

    The Earth's inner core, the slowly growing sphere of solid iron alloy at the centre of our planet, is known to exhibit seismic anisotropy. Both normal mode and body wave studies have established that, when the global average is taken, compressional waves propagate faster in the North-South direction

  2. Anisotropy of Earth's inner core intrinsic attenuation from seismic normal mode models

    NARCIS (Netherlands)

    Mäkinen, Anna M.; Deuss, Arwen; Redfern, Simon A T

    2014-01-01

    The Earth's inner core, the slowly growing sphere of solid iron alloy at the centre of our planet, is known to exhibit seismic anisotropy. Both normal mode and body wave studies have established that, when the global average is taken, compressional waves propagate faster in the North-South direction

  3. Long-term changes in structure and composition following hurricanes in a primary lower montane rain forest in Puerto Rico

    Science.gov (United States)

    P.L. Weaver

    2013-01-01

    Ridges within the lower montane rain forests (sensu Beard) of the Caribbean Basin are dominated by Dacryodes excelsa, a tree species known as tabonuco in Puerto Rico and gommier in the Lesser Antilles. Periodially, hurricanes traverse the islands causing changes in structure, species composition, and dynamics of forests. The chronology of post-hurricane vegetation...

  4. Thermochemical flows couple the Earth's inner core growth to mantle heterogeneity.

    Science.gov (United States)

    Aubert, Julien; Amit, Hagay; Hulot, Gauthier; Olson, Peter

    2008-08-07

    Seismic waves sampling the top 100 km of the Earth's inner core reveal that the eastern hemisphere (40 degrees E-180 degrees E) is seismically faster, more isotropic and more attenuating than the western hemisphere. The origin of this hemispherical dichotomy is a challenging problem for our understanding of the Earth as a system of dynamically coupled layers. Previously, laboratory experiments have established that thermal control from the lower mantle can drastically affect fluid flow in the outer core, which in turn can induce textural heterogeneity on the inner core solidification front. The resulting texture should be consistent with other expected manifestations of thermal mantle control on the geodynamo, specifically magnetic flux concentrations in the time-average palaeomagnetic field over the past 5 Myr, and preferred eddy locations in flows imaged below the core-mantle boundary by the analysis of historical geomagnetic secular variation. Here we show that a single model of thermochemical convection and dynamo action can account for all these effects by producing a large-scale, long-term outer core flow that couples the heterogeneity of the inner core with that of the lower mantle. The main feature of this thermochemical 'wind' is a cyclonic circulation below Asia, which concentrates magnetic field on the core-mantle boundary at the observed location and locally agrees with core flow images. This wind also causes anomalously high rates of light element release in the eastern hemisphere of the inner core boundary, suggesting that lateral seismic anomalies at the top of the inner core result from mantle-induced variations in its freezing rate.

  5. Influence of hurricane wind field in the structure of directional wave spectra

    Science.gov (United States)

    Esquivel-Trava, Bernardo; Ocampo-Torres, Francisco J.; Osuna, Pedro

    2015-04-01

    Extensive field measurements of wind waves in deep waters in the Gulf of Mexico and Caribbean Sea, have been analyzed to describe the spatial structure of directional wave spectra during hurricane conditions. Following Esquivel-Trava et al. (2015) this analysis was made for minor hurricanes (categories 1 and 2) and major hurricanes (categories 3, 4 and 5). In both cases the directionality of the energy wave spectrum is similar in all quadrants. Some differences are observed however, and they are associated with the presence and the shape of swell energy in each quadrant. Three numerical experiments using the spectral wave prediction model SWAN were carried out to gain insight into the mechanism that controls the directional and frequency distributions of hurricane wave energy. The aim of the experiments is to evaluate the effect of the translation speed of the hurricane and the presence of concentric eye walls, on both the wave growth process and the shape of the directional wave spectrum. The HRD wind field of Hurricane Dean on August 20 at 7:30 was propagated at two different velocities (5 and 10 m/s). An idealized concentric eye wall (a Gaussian function that evolve in time along a path in the form of an Archimedean spiral) was imposed to the wind field. The white-capping formulation of Westhuysen et al. (2007) was selected. The wave model represents fairly well the directionality of the energy and the shape of the directional spectra in the hurricane domain. The model results indicate that the forward movement of the storm influences the development of the waves, consistent with field observations. This work has been supported by CONACYT scholarship 164510 and projects RugDisMar (155793), CB-2011-01-168173 and the Department of Physical Oceanography of CICESE. References Esquivel-Trava, B., Ocampo-Torres, F. J., & Osuna, P. (2015). Spatial structure of directional wave spectra in hurricanes. Ocean Dynam., 65(1), 65-76. doi:10.1007/s10236-014-0791-9 Van der

  6. Hurricane Safety

    Science.gov (United States)

    ... English Hurricane Safety Checklist - Arabic Hurricane Safety Checklist - Chinese Hurricane Safety Checklist - French Hurricane Safety Checklist - Haitian ... Cross serves in the US, its territories and military installations around the world. Please try again. Your ...

  7. The axial ratio of hcp iron at the conditions of the Earth's inner core

    CERN Document Server

    Gannarelli, C M S; Gillian, M J

    2004-01-01

    We present ab initio calculations of the high-temperature axial c/a ratio of hexagonal-close-packed (hcp) iron at Earth's core pressures, in order to help interpret the observed seismic anisotropy of the inner core. The calculations are based on density functional theory, which is known to predict the properties of high-pressure iron with good accuracy. The temperature dependence of c/a is determined by minimising the Helmholtz free energy at fixed volume and temperature, with thermal contributions due to lattice vibrations calculated using harmonic theory. Anharmonic corrections to the harmonic predictions are estimated from calculations of the thermal average stress obtained from ab initio molecular dynamics simulations of hcp iron at the conditions of the inner core. We find a very gradual increase of axial ratio with temperature. This increase is much smaller than found in earlier calculations, but is in reasonable agreement with recent high-pressure, high-temperature diffraction measurements. This result...

  8. Bottom-up control of geomagnetic secular variation by the Earth's inner core.

    Science.gov (United States)

    Aubert, Julien; Finlay, Christopher C; Fournier, Alexandre

    2013-10-10

    Temporal changes in the Earth's magnetic field, known as geomagnetic secular variation, occur most prominently at low latitudes in the Atlantic hemisphere (that is, from -90 degrees east to 90 degrees east), whereas in the Pacific hemisphere there is comparatively little activity. This is a consequence of the geographical localization of intense, westward drifting, equatorial magnetic flux patches at the core surface. Despite successes in explaining the morphology of the geomagnetic field, numerical models of the geodynamo have so far failed to account systematically for this striking pattern of geomagnetic secular variation. Here we show that it can be reproduced provided that two mechanisms relying on the inner core are jointly considered. First, gravitational coupling aligns the inner core with the mantle, forcing the flow of liquid metal in the outer core into a giant, westward drifting, sheet-like gyre. The resulting shear concentrates azimuthal magnetic flux at low latitudes close to the core-mantle boundary, where it is expelled by core convection and subsequently transported westward. Second, differential inner-core growth, fastest below Indonesia, causes an asymmetric buoyancy release in the outer core which in turn distorts the gyre, forcing it to become eccentric, in agreement with recent core flow inversions. This bottom-up heterogeneous driving of core convection dominates top-down driving from mantle thermal heterogeneities, and localizes magnetic variations in a longitudinal sector centred beneath the Atlantic, where the eccentric gyre reaches the core surface. To match the observed pattern of geomagnetic secular variation, the solid material forming the inner core must now be in a state of differential growth rather than one of growth and melting induced by convective translation.

  9. Seismic parameters of hcp-Fe alloyed with Ni and Si in the Earth's inner core

    Science.gov (United States)

    Liu, Jin; Lin, Jung-Fu; Alatas, Ahmet; Hu, Michael Y.; Zhao, Jiyong; Dubrovinsky, Leonid

    2016-02-01

    Iron alloyed with Ni and Si has been suggested to be a major component of the Earth's inner core. High-pressure results on the combined alloying effects of Ni and Si on seismic parameters of iron are thus essential for establishing satisfactory geophysical and geochemical models of the region. Here we have investigated the compressional (VP) and shear (Vs) wave velocity-density (ρ) relations, Poisson's ratio (ν), and seismic heterogeneity ratios (dlnρ/dlnVP, dlnρ/dlnVS, and dlnVP/dlnVS) of hcp-Fe and hcp-Fe86.8Ni8.6Si4.6 alloy up to 206 GPa and 136 GPa, respectively, using multiple complementary techniques. Compared with the literature velocity values for hcp-Fe and Fe-Ni-Si alloys, our results show that the combined addition of 9.0 wt % Ni and 2.3 wt % Si slightly increases the VP but significantly decreases the VS of hcp-Fe at a given density relevant to the inner core. Such distinct alloying effects on velocities of hcp-Fe produce a high ν of about 0.40 for the alloy at inner core densities, which is approximately 20% higher than that for hcp-Fe. Analysis of the literature high P-T results on VP and VS of Fe alloyed with light elements shows that high temperature can further enhance the ν of hcp-Fe alloyed with Ni and Si. Most significantly, the derived seismic heterogeneity ratios of this hcp alloy present a better match with global seismic observations. Our results provide a multifactored geophysical constraint on the compositional model of the inner core which is consistent with silicon being a major light element alloyed with Fe and 5 wt % Ni.

  10. Evidence for inner-core rotation from possible changes with time in PKP coda

    Science.gov (United States)

    Vidale, John E.; Earle, Paul S.

    2005-01-01

    Inner-core-grazing PKP waves from seven French nuclear tests on Mururoa Island recorded at NORSAR appear to change over a decade. We compared filtered and stacked signals from the explosions, which took place from 1977 to 1987 and were separated by less than 10 km. The PKP energy 3 to 10 s after the first arrivals differs greatly between the NORSAR subarrays, and evolves over time. The small time shifts of coda arrivals, a few tenths of a second, are qualitatively consistent with shifts predicted for point scatterers in an inner core that rotates in the range 0.05° to 0.10° per year. There are also visible changes in the envelope of the PKP energy. Although the alternative of systematic shifts in source location cannot be ruled out, the apparent time evolution of PKP supports claims of slow inner core rotation [Song and Richards, 1996; Creager, 1997; Laske and Masters, 1999; Vidale et al., 2000] and offers a powerful new tool for its assessment.

  11. Core history from paleomagnetic data: Potential changes in stratification but no evidence for a Mesoproterozoic inner core age

    Science.gov (United States)

    Smirnov, Aleksey; Tarduno, John; Kulakov, Evgeniy; McEnroe, Suzanne; Bono, Richard

    2016-04-01

    Data on the long-term evolution of Earth's magnetic field intensity are crucial for understanding the mechanisms of the geodynamo and planetary evolution. However, the paleointensity record in rocks may be adversely affected by a plethora of physical processes which must be taken into account when analyzing the paleointensity database. Recently, a statistical analysis of the Precambrian paleointensity database was used to claim that the solid inner core formed in the Mesoproterozoic, and that this onset time constrains the thermal conductivity in the core to "moderate" values. Here, we demonstrate that the data selection criteria used in this analysis failed to filter out data that significantly overestimate the true paleofield strength due to the presence of non-ideal carriers of paleointensity signals and/or viscous re-magnetizations. Moreover, the use of site-mean data led to an additional statistical bias by giving equal weight to time-averaged and non-time-averaged data. When the paleointensity overestimates are removed, and the study-mean data are used instead of site-mean data, the Precambrian database does not indicate a robust change in geomagnetic field intensity during the Mesoproterozoic. Our analyses indicate that the presently available paleointensity data of Mesoproterozoic age are insufficient in number and quality to constrain the timing of solid inner core formation, or the outstanding problem of core thermal conductivity. More promising available data sets that reflect long-term core structure are geomagnetic reversal rate and field morphology. The latter suggests changes that may reflect differences in Archean to Proterozoic core stratification, whereas the former suggest an interval of geodynamo hyperactivity at ca 550 Ma.

  12. Role of Density Gradient Driven Trapped Electron Modes in the H-Mode Inner Core with Electron Heating

    Science.gov (United States)

    Ernst, D.

    2015-11-01

    We present new experiments and nonlinear gyrokinetic simulations showing that density gradient driven TEM (DGTEM) turbulence dominates the inner core of H-Mode plasmas during strong electron heating. Thus α-heating may degrade inner core confinement in H-Mode plasmas with moderate density peaking. These DIII-D low torque quiescent H-mode experiments were designed to study DGTEM turbulence. Gyrokinetic simulations using GYRO (and GENE) closely match not only particle, energy, and momentum fluxes, but also density fluctuation spectra, with and without ECH. Adding 3.4 MW ECH doubles Te /Ti from 0.5 to 1.0, which halves the linear TEM critical density gradient, locally flattening the density profile. Density fluctuations from Doppler backscattering (DBS) intensify near ρ = 0.3 during ECH, displaying a band of coherent fluctuations with adjacent toroidal mode numbers. GYRO closely reproduces the DBS spectrum and its change in shape and intensity with ECH, identifying these as coherent TEMs. Prior to ECH, parallel flow shear lowers the effective nonlinear DGTEM critical density gradient 50%, but is negligible during ECH, when transport displays extreme stiffness in the density gradient. GS2 predictions show the DGTEM can be suppressed, to avoid degradation with electron heating, by broadening the current density profile to attain q0 >qmin > 1 . A related experiment in the same regime varied the electron temperature gradient in the outer half-radius (ρ ~ 0 . 65) using ECH, revealing spatially coherent 2D mode structures in the Te fluctuations measured by ECE imaging. Fourier analysis with modulated ECH finds a threshold in Te profile stiffness. Supported by the US DOE under DE-FC02-08ER54966 and DE-FC02-04ER54698.

  13. Wide-scale detection of earthquake waveform doublets and further evidence for inner core super-rotation

    Science.gov (United States)

    Zhang, Jian; Richards, Paul G.; Schaff, David P.

    2008-09-01

    We report on more than 100 earthquake waveform doublets in five subduction zones, including an earthquake nest in Bucaramanga, Colombia. Each doublet is presumed to be a pair of earthquakes that repeat at essentially the same location. These doublets are important for studying earthquake physics, as well as temporal changes of the inner core. Particularly, our observation from one South Sandwich Islands (SSI) doublet recorded at station INK in Canada shows an inner core traveltime change of ~0.1 s over ~6 yr, confirming the inner-core differential motion occurring beneath Central America. Observations from one Aleutian Islands doublet, recorded at station BOSA in South Africa, and from one Kuril Islands doublet, recorded at station BDFB in Brazil, show an apparent inner core traveltime change of ~0.1 s over ~7 yr and ~6 yr, respectively, providing evidence for the temporal change of inner core properties beneath Central Asia and Canada, respectively. On the other hand, observations from one Tonga-Fiji-Solomon Islands doublet, recorded at station PTGA in Brazil, and from one Bucaramanga doublet, recorded at station WRAB in Australia and station CHTO in Thailand, show no/little temporal change (no more than 0.005 s yr-1, if any) of inner core traveltimes for the three corresponding ray paths for which the path in the inner core is nearly parallel to the equatorial plane. Such a pattern of observations showing both presence and possible absence of inner-core traveltime change can be explained by the geometry and relative directions of ray path, lateral velocity gradient and inner-core particle motion due to an eastward super-rotation of a few tenths of a degree per year.

  14. The Wavenumber-One Instability and Trochoidal Motion of Hurricane-like Vortices.

    Science.gov (United States)

    Nolan, David S.; Montgomery, Michael T.; Grasso, Lewis D.

    2001-11-01

    In a previous paper, the authors discussed the dynamics of an instability that occurs in inviscid, axisymmetric, two-dimensional vortices possessing a low-vorticity core surrounded by a high-vorticity annulus. Hurricanes, with their low-vorticity cores (the eye of the storm), are naturally occurring examples of such vortices. The instability is for asymmetric perturbations of azimuthal wavenumber-one about the vortex, and grows in amplitude as t1/2 for long times, despite the fact that there can be no exponentially growing wavenumber-one instabilities in inviscid, two-dimensional vortices. This instability is further studied in three fluid flow models: with high-resolution numerical simulations of two-dimensional flow, for linearized perturbations in an equivalent shallow-water vortex, and in a three-dimensional, baroclinic, hurricane-like vortex simulated with a high-resolution mesoscale numerical model.The instability is found to be robust in all of these physical models. Interestingly, the algebraic instability becomes an exponential instability in the shallow-water vortex, though the structures of the algebraic and exponential modes are nearly identical. In the three-dimensional baroclinic vortex, the instability quickly leads to substantial inner-core vorticity redistribution and mixing. The instability is associated with a displacement of the vortex center (as defined by either minimum pressure or streamfunction) that rotates around the vortex core, and thus offers a physical mechanism for the persistent, small-amplitude trochoidal wobble often observed in hurricane tracks. The instability also indicates that inner-core vorticity mixing will always occur in such vortices, even when the more familiar higher-wavenumber barotropic instabilities are not supported.

  15. Hurricanes Karl and Tropical Storm Matthew Structure Observed by HIWRAP During GRIP

    Science.gov (United States)

    Heymsfield, G. M.; Guimond, S. R.; Tian, L.

    2012-12-01

    The dual-wavelength (Ku and Ka band) High-Altitude Imaging Wind and Rain Airborne Profiler (HIWRAP) flew for the first time on the Global Hawk during the 2010 Genesis and Rapid Intensification Processes (GRIP). HIWRAP is conical scanning and Doppler, and winds and reflectivity can be mapped within the swath below the Global Hawk. Two interesting cases from the HIWRAP flights were the rapid intensification of Hurricane Karl and the intensification of Tropical Storm Matthew. This presentation will highlight the precipitation and wind structure of these storms during their intensification as derived from the HIWRAP observations. If time permits and if available, highlights from HIWRAP observations from the Hurricane Severe Storm Sentinel (HS3) field campaign in September 2012 will be presented.

  16. Formation of a solid inner core during the accretion of Earth

    Science.gov (United States)

    Arkani-Hamed, Jafar

    2017-05-01

    The formation of an inner core during the accretion of Earth is investigated by using self-gravitating and compressible Earth models formed by accreting a total of 25 or 50 Moon to Mars-sized planetary embryos. The impact of an embryo heats the proto-Earth's interior differentially, more below the impact site than elsewhere. The rotating core dynamically overturns and stratifies shortly after each impact, creating a spherically symmetric and radially increasing temperature distribution relative to an adiabatic profile. Merging of an embryo to the proto-Earth increases the lithostatic pressure that results in compressional temperature increase while further enhances the melting temperature of the core causing solidification. A total of 36 thermal evolution models of the growing proto-Earth's core are calculated to investigate effects of major physical parameters. No solidification is considered in the first 21 models where modified two-body escape velocities are used as the impact velocities of the embryos. At the end of accretion, temperatures in the upper part of the core are significantly different among these models, whereas temperatures in the deeper parts are similar. The core solidification considered in the remaining 15 models, where impact velocities higher than the modified two-body escape velocities are adopted, drastically changes the temperature distribution in the deeper parts of the core. All of the models produce partially solidified stiff inner cores, 1000-2100 km in radius, at the end of accretion, where the solid fraction is larger than 50%. The innermost of the stiff inner cores is completely solidified to radii 250-1500 km.

  17. Melting-induced stratification above the Earth's inner core due to convective translation

    OpenAIRE

    Alboussiere, Thierry; Deguen, Renaud; Melzani, Mickael

    2010-01-01

    International audience; In addition to its global North-South anisotropy(1), there are two other enigmatic seismological observations related to the Earth's inner core: asymmetry between its eastern and western hemispheres(2-6) and the presence of a layer of reduced seismic velocity at the base of the outer core(6-12). This 250-km-thick layer has been interpreted as a stably stratified region of reduced composition in light elements(13). Here we show that this layer can be generated by simult...

  18. Radiative emission of neutrino pair from nucleus and inner core electrons in heavy atoms

    CERN Document Server

    Yoshimura, M

    2013-01-01

    Radiative emission of neutrino pair (RENP) from atomic states is a new tool to experimentally investigate undetermined neutrino parameters such as the smallest neutrino mass, the nature of neutrino masses (Majorana vs Dirac), and their CP properties. We study effects of neutrino pair emission either from nucleus or from inner core electrons in which the zero-th component of quark or electron vector current gives rise to large coupling. Both the overall rate and the spectral shape of photon energy are given for a few cases of interesting target atoms. Calculated rates exceed those of previously considered target atoms by many orders of magnitudes.

  19. Aeroelastic Modeling of Offshore Turbines and Support Structures in Hurricane-Prone Regions (Poster)

    Energy Technology Data Exchange (ETDEWEB)

    Damiani, R.

    2014-03-01

    US offshore wind turbines (OWTs) will likely have to contend with hurricanes and the associated loading conditions. Current industry standards do not account for these design load cases (DLCs), thus a new approach is required to guarantee that the OWTs achieve an appropriate level of reliability. In this study, a sequentially coupled aero-hydro-servo-elastic modeling technique was used to address two design approaches: 1.) The ABS (American Bureau of Shipping) approach; and 2.) The Hazard Curve or API (American Petroleum Institute) approach. The former employs IEC partial load factors (PSFs) and 100-yr return-period (RP) metocean events. The latter allows setting PSFs and RP to a prescribed level of system reliability. The 500-yr RP robustness check (appearing in [2] and [3] upcoming editions) is a good indicator of the target reliability for L2 structures. CAE tools such as NREL's FAST and Bentley's' SACS (offshore analysis and design software) can be efficiently coupled to simulate system loads under hurricane DLCs. For this task, we augmented the latest FAST version (v. 8) to include tower aerodynamic drag that cannot be ignored in hurricane DLCs. In this project, a 6 MW turbine was simulated on a typical 4-legged jacket for a mid-Atlantic site. FAST-calculated tower base loads were fed to SACS at the interface level (transition piece); SACS added hydrodynamic and wind loads on the exposed substructure, and calculated mudline overturning moments, and member and joint utilization. Results show that CAE tools can be effectively used to compare design approaches for the design of OWTs in hurricane regions and to achieve a well-balanced design, where reliability levels and costs are optimized.

  20. Combining nutation and surface gravity observations to estimate the Earth's core and inner core resonant frequencies

    Science.gov (United States)

    Ziegler, Yann; Lambert, Sébastien; Rosat, Séverine; Nurul Huda, Ibnu; Bizouard, Christian

    2017-04-01

    Nutation time series derived from very long baseline interferometry (VLBI) and time varying surface gravity data recorded by superconducting gravimeters (SG) have long been used separately to assess the Earth's interior via the estimation of the free core and inner core resonance effects on nutation or tidal gravity. The results obtained from these two techniques have been shown recently to be consistent, making relevant the combination of VLBI and SG observables and the estimation of Earth's interior parameters in a single inversion. We present here the intermediate results of the ongoing project of combining nutation and surface gravity time series to improve estimates of the Earth's core and inner core resonant frequencies. We use VLBI nutation time series spanning 1984-2016 derived by the International VLBI Service for geodesy and astrometry (IVS) as the result of a combination of inputs from various IVS analysis centers, and surface gravity data from about 15 SG stations. We address here the resonance model used for describing the Earth's interior response to tidal excitation, the data preparation consisting of the error recalibration and amplitude fitting for nutation data, and processing of SG time-varying gravity to remove any gaps, spikes, steps and other disturbances, followed by the tidal analysis with the ETERNA 3.4 software package, the preliminary estimates of the resonant periods, and the correlations between parameters.

  1. Earth's core and inner-core resonances from analysis of VLBI nutation and superconducting gravimeter data

    Science.gov (United States)

    Rosat, S.; Lambert, S. B.; Gattano, C.; Calvo, M.

    2017-01-01

    Geophysical parameters of the deep Earth's interior can be evaluated through the resonance effects associated with the core and inner-core wobbles on the forced nutations of the Earth's figure axis, as observed by very long baseline interferometry (VLBI), or on the diurnal tidal waves, retrieved from the time-varying surface gravity recorded by superconducting gravimeters (SGs). In this paper, we inverse for the rotational mode parameters from both techniques to retrieve geophysical parameters of the deep Earth. We analyse surface gravity data from 15 SG stations and VLBI delays accumulated over the last 35 yr. We show existing correlations between several basic Earth parameters and then decide to inverse for the rotational modes parameters. We employ a Bayesian inversion based on the Metropolis-Hastings algorithm with a Markov-chain Monte Carlo method. We obtain estimates of the free core nutation resonant period and quality factor that are consistent for both techniques. We also attempt an inversion for the free inner-core nutation (FICN) resonant period from gravity data. The most probable solution gives a period close to the annual prograde term (or S1 tide). However the 95 per cent confidence interval extends the possible values between roughly 28 and 725 d for gravity, and from 362 to 414 d from nutation data, depending on the prior bounds. The precisions of the estimated long-period nutation and respective small diurnal tidal constituents are hence not accurate enough for a correct determination of the FICN complex frequency.

  2. Inner Core Rotation from Geomagnetic Westward Drift and a Stationary Spherical Vortex in Earth's Core

    Science.gov (United States)

    Voorhies, C. V.

    1999-01-01

    The idea that geomagnetic westward drift indicates convective leveling of the planetary momentum gradient within Earth's core is pursued in search of a differentially rotating mean state, upon which various oscillations and secular effects might be superimposed. The desired state conforms to roughly spherical boundary conditions, minimizes dissipative interference with convective cooling in the bulk of the core, yet may aide core cooling by depositing heat in the uppermost core and lower mantle. The variational calculus of stationary dissipation applied to a spherical vortex within the core yields an interesting differential rotation profile akin to spherical Couette flow bounded by thin Hartmann layers. Four boundary conditions are required. To concentrate shear induced dissipation near the core-mantle boundary, these are taken to be: (i) no-slip at the core-mantle interface; (ii) geomagnetically estimated bulk westward flow at the base of the core-mantle boundary layer; (iii) no-slip at the inner-outer core interface; and, to describe magnetic locking of the inner core to the deep outer core, (iv) hydrodynamically stress-free at the inner-outer core boundary. By boldly assuming the axial core angular momentum anomaly to be zero, the super-rotation of the inner core is calculated to be at most 1.5 degrees per year.

  3. An in-fiber integrated optofluidic device based on an optical fiber with an inner core.

    Science.gov (United States)

    Yang, Xinghua; Yuan, Tingting; Teng, Pingping; Kong, Depeng; Liu, Chunlan; Li, Entao; Zhao, Enming; Tong, Chengguo; Yuan, Libo

    2014-06-21

    A new kind of optofluidic in-fiber integrated device based on a specially designed hollow optical fiber with an inner core is designed. The inlets and outlets are built by etching the surface of the optical fiber without damaging the inner core. A reaction region between the end of the fiber and a solid point obtained after melting is constructed. By injecting samples into the fiber, the liquids can form steady microflows and react in the region. Simultaneously, the emission from the chemiluminescence reaction can be detected from the remote end of the optical fiber through evanescent field coupling. The concentration of ascorbic acid (AA or vitamin C, Vc) is determined by the emission intensity of the reaction of Vc, H2O2, luminol, and K3Fe(CN)6 in the optical fiber. A linear sensing range of 0.1-3.0 mmol L(-1) for Vc is obtained. The emission intensity can be determined within 2 s at a total flow rate of 150 μL min(-1). Significantly, this work presents information for the in-fiber integrated optofluidic devices without spatial optical coupling.

  4. Influence of surface displacement on solid state flow induced by horizontally heterogeneous Joule heating in the inner core of the Earth

    Science.gov (United States)

    Takehiro, Shin-ichi

    2015-04-01

    We investigate the influence of surface displacement on fluid motions induced by horizontally heterogeneous Joule heating in the inner core. The difference between the governing equations and those of Takehiro (2011) is the boundary conditions at the inner core boundary (ICB). The temperature disturbance at the ICB coincides with the melting temperature, which varies depending on the surface displacement. The normal component of stress equalizes with the buoyancy induced by the surface displacement. The toroidal magnetic field and surface displacement with the horizontal structure of Y20 spherical harmonics is given. The flow fields are calculated numerically for various amplitudes of surface displacement with the expected values of the parameters of the core. Further, by considering the heat balance at the ICB, the surface displacement amplitude is related to the turbulent velocity amplitude in the outer core, near the ICB. The results show that when the turbulent velocity is on the order of 10-1 -10-2 m/s, the flow and stress fields are similar to those of Takehiro (2011), where the surface displacement vanishes. As the amplitude of the turbulent velocity decreases, the amplitude of the surface displacement increases, and counter flows from the polar to equatorial regions emerge around the ICB, while flow in the inner regions is directed from the equatorial to polar regions, and the non-zero radial component of velocity at the ICB remains. When the turbulent velocity is on the order of 10-4 -10-5 m/s, the radial component of velocity at the ICB vanishes, the surface counter flows become stronger than the flow in the inner region, and the amplitude of the stress field near the ICB dominates the inner region, which might be unsuitable for explaining the elastic anisotropy in the inner core.

  5. The elastic properties of hcp-Fe1 - xSix at Earth's inner-core conditions

    Science.gov (United States)

    Martorell, Benjamí; Wood, Ian G.; Brodholt, John; Vočadlo, Lidunka

    2016-10-01

    The density of the Earth's inner core is less than that of pure iron and the P-wave velocities and, particularly, the S-wave velocities in the inner core observed from seismology are lower than those generally obtained from mineral physics. On the basis of measurements of compressional sound velocities to ∼100 GPa in diamond-anvil cells, extrapolated to inner-core pressures, it has been suggested that both the inner-core density and P-wave velocity can be matched simultaneously by the properties of a hexagonal-close-packed (hcp) Fe-Si or Fe-Ni-Si alloy. In this paper we present the results of ab initio molecular dynamics simulations of hcp-Fe-Si alloys at 360 GPa and at temperatures up to melting. We find that although the inner-core density can be readily matched by an Fe-Si alloy, the same is not true for the wave velocities. At inner-core temperatures, the P-wave velocity in hcp-Fe-Si remains equal to, or slightly above, that of hcp-Fe and shows little change with silicon content. The S-wave velocity is reduced with respect to that of pure hcp-iron, except for temperatures immediately prior to melting, where the velocities are almost equal; this is a consequence of the fact that the strong temperature dependence of the shear modulus that was seen in similar simulations of hcp-Fe just prior to melting was not found in hcp-Fe-Si, and so in this temperature range the reduced S-wave velocity of pure iron closely matches that of the alloy. Our results show that for an hcp-Fe-Si alloy matching the inner-core density, both the P-wave and the S-wave velocities will be higher than those observed by seismology and we conclude, therefore, that our calculations indicate that inner core velocities cannot be explained by an hcp-Fe-Si alloy. The opposite conclusion, obtained previously from experimental data measured at lower pressures, is a consequence of: (i) the necessarily large extrapolation in pressure and temperature required to extend the experimental results to

  6. Hurricane Science

    Science.gov (United States)

    Emanuel, Kerry

    2012-10-01

    Hurricanes provide beautiful examples of many of the key physical processes important in geophysical systems. They are rare natural examples of nearly perfect Carnot heat engines with an interesting wrinkle: They recycle much of their waste heat into the front end of the engine, thereby achieving greater wind speeds than would otherwise be possible. They are driven by surface enthalpy fluxes made possible by the thermodynamic disequilibrium between the earth's surface and atmosphere, a characteristic of radiative equilibrium in the presence of greenhouse gases. Their evolution, structure, and intensity all depend on turbulence near the ocean surface and in the outflow layer of the storm, high up in the atmosphere. In the course of this banquet, I will briefly describe these and other interesting aspects of hurricane physics, and also describe the role these storms have played in human history.

  7. Surface atmospheric pressure excitation of the translational mode of the inner core

    CERN Document Server

    Rosat, Séverine; Rogister, Yves

    2014-01-01

    Using hourly atmospheric surface pressure field from ECMWF (European Centre for Medium-Range Weather Forecasts) and from NCEP (National Centers for Environmental Prediction) Climate Forecast System Reanalysis (CFSR) models, we show that atmospheric pressure fluctuations excite the translational oscillation of the inner core, the so-called Slichter mode, to the sub-nanogal level at the Earth surface. The computation is performed using a normal-mode formalism for a spherical, self-gravitating anelastic PREM-like Earth model. We determine the statistical response in the form of power spectral densities of the degree-one spherical harmonic components of the observed pressure field. Both hypotheses of inverted and non-inverted barometer for the ocean response to pressure forcing are considered. Based on previously computed noise levels, we show that the surface excitation amplitude is below the limit of detection of the superconducting gravimeters, making the Slichter mode detection a challenging instrumental task...

  8. The Impact of Microphysics on Intensity and Structure of Hurricanes and Mesoscale Convective Systems

    Science.gov (United States)

    Tao, Wei-Kuo; Shi, Jainn J.; Jou, Ben Jong-Dao; Lee, Wen-Chau; Lin, Pay-Liam; Chang, Mei-Yu

    2007-01-01

    During the past decade, both research and operational numerical weather prediction models, e.g. Weather Research and Forecast (WRF) model, have started using more complex microphysical schemes originally developed for high-resolution cloud resolving models (CRMs) with a 1-2 km or less horizontal resolutions. WRF is a next-generation mesoscale forecast model and assimilation system that has incorporated modern software framework, advanced dynamics, numeric and data assimilation techniques, a multiple moveable nesting capability, and improved physical packages. WRF model can be used for a wide range of applications, from idealized research to operational forecasting, with an emphasis on horizontal grid sizes in the range of 1-10 km. The current WRF includes several different microphysics options such as Purdue Lin et al. (1983), WSM 6-class and Thompson microphysics schemes. We have recently implemented three sophisticated cloud microphysics schemes into WRF. The cloud microphysics schemes have been extensively tested and applied for different mesoscale systems in different geographical locations. The performances of these schemes have been compared to those from other WRF microphysics options. We are performing sensitivity tests in using WRF to examine the impact of six different cloud microphysical schemes on precipitation processes associated hurricanes and mesoscale convective systems developed at different geographic locations [Oklahoma (IHOP), Louisiana (Hurricane Katrina), Canada (C3VP - snow events), Washington (fire storm), India (Monsoon), Taiwan (TiMREX - terrain)]. We will determine the microphysical schemes for good simulated convective systems in these geographic locations. We are also performing the inline tracer calculation to comprehend the physical processes (i.e., boundary layer and each quadrant in the boundary layer) related to the development and structure of hurricanes and mesoscale convective systems.

  9. Grain growth of ε-iron: Implications to grain size and its evolution in the Earth's inner core

    Science.gov (United States)

    Yamazaki, Daisuke; Tsujino, Noriyoshi; Yoneda, Akira; Ito, Eiji; Yoshino, Takashi; Tange, Yoshinori; Higo, Yuji

    2017-02-01

    Knowledge of grain growth rate of ε-iron can put constraint on estimation of the grain size in the inner core. We determined grain growth rate of ε-iron at ∼55 GPa and 1200-1500 K by means of in-situ X-ray diffraction observation to be Gn - G0n = kt, where G (m) is the grain size at time t (s), G0 (m) is the initial grain size, n is growth exponent (fixed to 2) and k is the growth constant expressed as k =k0 exp ⁡ (-H* / RT) with log k0 (mn /s) = - 5.8 (± 2.4) and activation enthalpy H* = 221 (± 61) kJ /mol, and R is the gas constant and T is the absolute temperature. Extrapolation of the grain growth law of ε-iron to the inner core conditions suggests that the grain size in the inner core is in a range from several hundred meters to several kilometers, which is intermediate among the previous estimations, and hence the dominant deformation mechanism is considered to be Harper-Dorn creep rather than diffusion creep as pointed out by the previous work. This indicates the relatively uniform viscosity in the entire inner core.

  10. Constraints on Earth's inner core composition inferred from measurements of the sound velocity of hcp-iron in extreme conditions.

    Science.gov (United States)

    Sakamaki, Tatsuya; Ohtani, Eiji; Fukui, Hiroshi; Kamada, Seiji; Takahashi, Suguru; Sakairi, Takanori; Takahata, Akihiro; Sakai, Takeshi; Tsutsui, Satoshi; Ishikawa, Daisuke; Shiraishi, Rei; Seto, Yusuke; Tsuchiya, Taku; Baron, Alfred Q R

    2016-02-01

    Hexagonal close-packed iron (hcp-Fe) is a main component of Earth's inner core. The difference in density between hcp-Fe and the inner core in the Preliminary Reference Earth Model (PREM) shows a density deficit, which implies an existence of light elements in the core. Sound velocities then provide an important constraint on the amount and kind of light elements in the core. Although seismological observations provide density-sound velocity data of Earth's core, there are few measurements in controlled laboratory conditions for comparison. We report the compressional sound velocity (V P) of hcp-Fe up to 163 GPa and 3000 K using inelastic x-ray scattering from a laser-heated sample in a diamond anvil cell. We propose a new high-temperature Birch's law for hcp-Fe, which gives us the V P of pure hcp-Fe up to core conditions. We find that Earth's inner core has a 4 to 5% smaller density and a 4 to 10% smaller V P than hcp-Fe. Our results demonstrate that components other than Fe in Earth's core are required to explain Earth's core density and velocity deficits compared to hcp-Fe. Assuming that the temperature effects on iron alloys are the same as those on hcp-Fe, we narrow down light elements in the inner core in terms of the velocity deficit. Hydrogen is a good candidate; thus, Earth's core may be a hidden hydrogen reservoir. Silicon and sulfur are also possible candidates and could show good agreement with PREM if we consider the presence of some melt in the inner core, anelasticity, and/or a premelting effect.

  11. Melting of iron close to Earth's inner core boundary conditions and beyond

    CERN Document Server

    Harmand, M; Mazevet, S; Bouchet, J; Denoeud, A; Dorchies, F; Feng, Y; Fourment, C; Galtier, E; Gaudin, J; Guyot, F; Kodama, R; Koenig, M; Lee, H J; Miyanishi, K; Morard, G; Musella, R; Nagler, B; Nakatsutsumi, M; Ozaki, N; Recoules, V; Toleikis, S; Vinci, T; Zastrau, U; Zhu, D; Benuzzi-Mounaix, A

    2014-01-01

    Several important geophysical features such as heat flux at the Core-Mantle Boundary or geodynamo production are intimately related with the temperature profile in the Earth's core. However, measuring the melting curve of iron at conditions corresponding to the Earth inner core boundary under pressure of 330 GPa has eluded scientists for several decades. Significant discrepancies in previously reported iron melting temperatures at high pressure have called into question the validity of dynamic measurements. We report measurements made with a novel approach using X-ray absorption spectroscopy using an X-ray free electron laser source coupled to a laser shock experiment. We determine the state of iron along the shock Hugoniot up to 420 GPa (+/- 50) and 10800 K (+/- 1390) and find an upper boundary for the melting curve of iron by detecting solid iron at 130 GPa and molten at 260, 380 and 420 GPa along the shock Hugoniot. Our result establishes unambiguous agreement between dynamic measurement and recent extrapo...

  12. FY05 LDRD Final Report The Innermost Inner Core: Fact or Artifact?

    Energy Technology Data Exchange (ETDEWEB)

    Tkalcic, H; Flanagan, M P; Mogri, H

    2006-01-09

    P'P' (PKPPKP) are P waves that travel from a hypocenter through the Earth's core, reflect from the free surface and travel back through the core to a recording station on the surface. Here we report the observations of hitherto unobserved near-podal P'P' waves (at epicentral distance < 10{sup o}) and very prominent precursors preceding the main energy by as much as 60 s. We interpret these precursors as a back-scattered energy from previously undocumented horizontally connected small-scale heterogeneity in the upper mantle beneath the oceans in a zone between 150 and 220 km depth beneath the Earth's surface. From these observations, we identify a frequency dependence of attenuation quality factor Q in the lithosphere through forward modeling of the observed amplitude spectra of the main and back-scattered P'P' waves. In addition, we did not find that travel times corresponding to very polar paths through the centermost inner core with respect to the rotation axis of Earth are anomalously advanced, which argues for isotropic or at best --weakly-anisotropic center of Earth in the direction parallel with the rotation axis. More systematic sampling near Earth's center and characterization of anisotropy in Earth's center will be a subject of future research efforts.

  13. Possible generation of heat from nuclear fusion in Earth’s inner core

    Science.gov (United States)

    Fukuhara, Mikio

    2016-11-01

    The cause and source of the heat released from Earth’s interior have not yet been determined. Some research groups have proposed that the heat is supplied by radioactive decay or by a nuclear georeactor. Here we postulate that the generation of heat is the result of three-body nuclear fusion of deuterons confined in hexagonal FeDx core-centre crystals; the reaction rate is enhanced by the combined attraction effects of high-pressure (~364 GPa) and high-temperature (~5700 K) and by the physical catalysis of neutral pions: 2D + 2D + 2D → 21H + 4He + 2  + 20.85 MeV. The possible heat generation rate can be calculated as 8.12 × 1012 J/m3, based on the assumption that Earth’s primitive heat supply has already been exhausted. The H and He atoms produced and the anti-neutrino are incorporated as Fe-H based alloys in the H-rich portion of inner core, are released from Earth’s interior to the universe, and pass through Earth, respectively.

  14. Possible generation of heat from nuclear fusion in Earth's inner core.

    Science.gov (United States)

    Fukuhara, Mikio

    2016-11-23

    The cause and source of the heat released from Earth's interior have not yet been determined. Some research groups have proposed that the heat is supplied by radioactive decay or by a nuclear georeactor. Here we postulate that the generation of heat is the result of three-body nuclear fusion of deuterons confined in hexagonal FeDx core-centre crystals; the reaction rate is enhanced by the combined attraction effects of high-pressure (~364 GPa) and high-temperature (~5700 K) and by the physical catalysis of neutral pions: (2)D + (2)D + (2)D → 2(1)H + (4)He + 2  + 20.85 MeV. The possible heat generation rate can be calculated as 8.12 × 10(12) J/m(3), based on the assumption that Earth's primitive heat supply has already been exhausted. The H and He atoms produced and the anti-neutrino are incorporated as Fe-H based alloys in the H-rich portion of inner core, are released from Earth's interior to the universe, and pass through Earth, respectively.

  15. Bottom-up control of geomagnetic secular variation by the Earth's inner core

    DEFF Research Database (Denmark)

    Aubert, Julien; Finlay, Chris; Fournier, Alexandre

    2013-01-01

    Temporal changes in the Earth’s magnetic field, known as geomagnetic secular variation, occur most prominently at low latitudes in the Atlantic hemisphere1, 2 (that is, from −90 degrees east to 90 degrees east), whereas in the Pacific hemisphere there is comparatively little activity. This is a c......Temporal changes in the Earth’s magnetic field, known as geomagnetic secular variation, occur most prominently at low latitudes in the Atlantic hemisphere1, 2 (that is, from −90 degrees east to 90 degrees east), whereas in the Pacific hemisphere there is comparatively little activity....... This is a consequence of the geographical localization of intense, westward drifting, equatorial magnetic flux patches at the core surface3. Despite successes in explaining the morphology of the geomagnetic field4, numerical models of the geodynamo have so far failed to account systematically for this striking pattern......-like gyre6. The resulting shear concentrates azimuthal magnetic flux at low latitudes close to the core–mantle boundary, where it is expelled by core convection and subsequently transported westward. Second, differential inner-core growth7, 8, fastest below Indonesia6, 9, causes an asymmetric buoyancy...

  16. Geologic effects of hurricanes

    Science.gov (United States)

    Coch, Nicholas K.

    1994-08-01

    Hurricanes are intense low pressure systems of tropical origin. Hurricane damage results from storm surge, wind, and inland flooding from heavy rainfall. Field observations and remote sensing of recent major hurricanes such as Hugo (1989), Andrew (1992) and Iniki (1992) are providing new insights into the mechanisms producing damage in these major storms. Velocities associated with hurricanes include the counterclockwise vortex winds flowing around the eye and the much slower regional winds that steer hurricane and move it forward. Vectorial addition of theseof these two winds on the higher effective wind speed than on the left side. Coast-parallel hurricane tracks keep the weaker left side of the storm against the coast, whereas coast-normal tracks produce a wide swath of destruction as the more powerful right side of the storm cuts a swath of destruction hundreds of kilometers inland. Storm surge is a function of the wind speed, central pressure, shelf slope, shoreline configuration, and anthropogenic alterations to the shoreline. Maximum surge heights are not under the eye of the hurricane, where the pressure is lowest, but on the right side of the eye at the radius of maximum winds, where the winds are strongest. Flood surge occurs as the hurricane approaches land and drives coastal waters, and superimposed waves, across the shore. Ebb surge occurs when impounded surface water flows seaward as the storm moves inland. Flood and ebb surge damage have been greatly increased in recent hurricanes as a result of anthropogenic changes along the shoreline. Hurricane wind damage occurs on three scales — megascale, mesoscale and microscale. Local wind damage is a function of wind speed, exposure and structural resistance to velocity pressure, wind drag and flying debris. Localized extreme damage is caused by gusts that can locally exceed sustained winds by a factor of two in areas where there is strong convective activity. Geologic changes occuring in hurricanes

  17. Numerical models of the Earth’s thermal history: Effects of inner-core solidification and core potassium

    Science.gov (United States)

    Butler, S. L.; Peltier, W. R.; Costin, S. O.

    2005-09-01

    Recently there has been renewed interest in the evolution of the inner core and in the possibility that radioactive potassium might be found in significant quantities in the core. The arguments for core potassium come from considerations of the age of the inner core and the energy required to sustain the geodynamo [Nimmo, F., Price, G.D., Brodholt, J., Gubbins, D., 2004. The influence of potassium on core and geodynamo evolution. Geophys. J. Int. 156, 363-376; Labrosse, S., Poirier, J.-P., Le Mouël, J.-L., 2001. The age of the inner core. Earth Planet Sci. Lett. 190, 111-123; Labrosse, S., 2003. Thermal and magnetic evolution of the Earth's core. Phys. Earth Planet Int. 140, 127-143; Buffett, B.A., 2003. The thermal state of Earth's core. Science 299, 1675-1677] and from new high pressure physics analyses [Lee, K., Jeanloz, R., 2003. High-pressure alloying of potassium and iron: radioactivity in the Earth's core? Geophys. Res. Lett. 30 (23); Murthy, V.M., van Westrenen, W., Fei, Y.W., 2003. Experimental evidence that potassium is a substantial radioactive heat source in planetary cores. Nature 423, 163-165; Gessmann, C.K., Wood, B.J., 2002. Potassium in the Earth's core? Earth Planet Sci. Lett. 200, 63-78]. The Earth's core is also located at the lower boundary of the convecting mantle and the presence of radioactive heat sources in the core will affect the flux of heat between these two regions and will, as a result, have a significant impact on the Earth's thermal history. In this paper, we present Earth thermal history simulations in which we calculate fluid flow in a spherical shell representing the mantle, coupled with a core of a given heat capacity with varying degrees of internal heating in the form of K40 and varying initial core temperatures. The mantle model includes the effects of the temperature dependence of viscosity, decaying radioactive heat sources, and mantle phase transitions. The core model includes the thermal effects of inner core

  18. The particle-in-cell model for ab initio thermodynamics: implications for the elastic anisotropy of the Earth's inner core

    CERN Document Server

    Gannarelli, C M S; Gillan, M J

    2003-01-01

    We assess the quantitative accuracy of the particle-in-cell (PIC) approximation used in recent ab initio predictions of the thermodynamic properties of hexagonal-close-packed iron at the conditions of the Earth's inner core. The assessment is made by comparing PIC predictions for a range of thermodynamic properties with the results of more exact calculations that avoid the PIC approximation. It is shown that PIC gives very accurate results for some properties, but that it gives an incorrect treatment of anharmonic lattice vibrations. In addition, our assessment does not support recent PIC-based predictions that the hexagonal c/a ratio increases strongly with increasing temperature, and we point out that this casts doubt on a proposed re-interpretation of the elastic anisotropy of the inner core.

  19. First-principles prediction of Si-doped Fe carbide as one of the possible constituents of Earth's inner core

    Science.gov (United States)

    Das, Tilak; Chatterjee, Swastika; Ghosh, Sujoy; Saha-Dasgupta, Tanusri

    2017-09-01

    We perform a computational study based on first-principles calculations to investigate the relative stability and elastic properties of the doped and undoped Fe carbide compounds at 200-364 GPa. We find that upon doping a few weight percent of Si impurities at the carbon sites in Fe7C3 carbide phases, the values of Poisson's ratio and density increase while VP, and VS decrease compared to their undoped counterparts. This leads to marked improvement in the agreement of seismic parameters such as P wave and S wave velocity, Poisson's ratio, and density with the Preliminary Reference Earth Model (PREM) data. The agreement with PREM data is found to be better for the orthorhombic phase of iron carbide (o-Fe7C3) compared to hexagonal phase (h-Fe7C3). Our theoretical analysis indicates that Fe carbide containing Si impurities can be a possible constituent of the Earth's inner core. Since the density of undoped Fe7C3 is low compared to that of inner core, as discussed in a recent theoretical study, our proposal of Si-doped Fe7C3 can provide an alternative solution as an important component of the Earth's inner core.

  20. Role of density gradient driven trapped electron mode turbulence in the H-mode inner core with electron heating

    Science.gov (United States)

    Ernst, D. R.; Burrell, K. H.; Guttenfelder, W.; Rhodes, T. L.; Dimits, A. M.; Bravenec, R.; Grierson, B. A.; Holland, C.; Lohr, J.; Marinoni, A.; McKee, G. R.; Petty, C. C.; Rost, J. C.; Schmitz, L.; Wang, G.; Zemedkun, S.; Zeng, L.

    2016-05-01

    A series of DIII-D [J. L. Luxon, Nucl. Fusion 42, 614 (2002)] low torque quiescent H-mode experiments show that density gradient driven trapped electron mode (DGTEM) turbulence dominates the inner core of H-mode plasmas during strong electron cyclotron heating (ECH). Adding 3.4 MW ECH doubles Te/Ti from 0.5 to 1.0, which halves the linear DGTEM critical density gradient, locally reducing density peaking, while transport in all channels displays extreme stiffness in the density gradient. This suggests that fusion α-heating may degrade inner core confinement in H-mode plasmas with moderate density peaking and low collisionality, with equal electron and ion temperatures, key conditions expected in burning plasmas. Gyrokinetic simulations using GYRO [J. Candy and R. E. Waltz, J. Comput. Phys. 186, 545 (2003)] (and GENE [Jenko et al., Phys. Plasmas 7, 1904 (2000)]) closely match not only particle, energy, and momentum fluxes but also density fluctuation spectra from Doppler backscattering (DBS), with and without ECH. Inner core DBS density fluctuations display discrete frequencies with adjacent toroidal mode numbers, which we identify as DGTEMs. GS2 [Dorland et al., Phys. Rev. Lett. 85, 5579 (2000)] predictions show the DGTEM can be suppressed, to avoid degradation with electron heating, by broadening the current density profile to attain q0>qmin>1 .

  1. Uppermost Inner Core Heterogeneity from Differential Travel Times of PKIKP vs. PKP-Bdiff and PKP-Cdiff Phases

    Science.gov (United States)

    Ivan, Marian; He, Xiaobo

    2017-01-01

    We evaluate the average P-wave velocity perturbations of the Earth's uppermost inner core (IC) by analyzing two pairs of core phases: PKIKP-PKP-Bdiff (456 observations in the distance range of 138.5°-142°) and PKIKP-PKP-Cdiff (1215 observations at 155°-162°). The former is most sensitive to inner core velocities in the depth range of 350-590 km and the latter from 0 to 100 km below the inner core boundary. The differential travel-time residuals exhibit the roughly "east-west" hemispheric pattern especially beneath the Pacific Ocean. Here, the separation between the two quasi-hemispheres is near the 150°W meridian (from PKP-Bdiff observations), but possibly rotated toward a NW-SE orientation, from PKP-Cdiff. Alternately, a velocity heterogeneity could be present here, in agreement with the previously reported PKIKP vs. PKPBC observations. Assuming the conventional definition for the IC quasi-hemispheres (i.e., the QEH between 0° and 180°E, and the QWH between 0° and 180°W), the quasi-Eastern hemisphere exhibits perturbations of (+1.17 ± 0.04) % (from PKIKP-PKP-Bdiff) and (+0.19 ± 0.01) % (from PKIKP-PKP-Cdiff). The corresponding perturbations in the quasi-Western hemisphere are of (-0.06 ± 0.06) % and (-0.19 ± 0.02) %, respectively. An anomalous IC zone beneath the Indian Ocean is not conspicuous in our PKIKP-PKP-Cdiff observations. Beneath the North Atlantic, the separation between the IC quasi-hemispheres appears to be located between 60°W and 30°W from the PKP-Bdiff observations, but it remains unresolved from the PKP-Cdiff data, due to scarce observations here.

  2. Uppermost Inner Core Heterogeneity from Differential Travel Times of PKIKP vs. PKP-Bdiff and PKP-Cdiff Phases

    Science.gov (United States)

    Ivan, Marian; He, Xiaobo

    2016-09-01

    We evaluate the average P-wave velocity perturbations of the Earth's uppermost inner core (IC) by analyzing two pairs of core phases: PKIKP-PKP-Bdiff (456 observations in the distance range of 138.5°-142°) and PKIKP-PKP-Cdiff (1215 observations at 155°-162°). The former is most sensitive to inner core velocities in the depth range of 350-590 km and the latter from 0 to 100 km below the inner core boundary. The differential travel-time residuals exhibit the roughly "east-west" hemispheric pattern especially beneath the Pacific Ocean. Here, the separation between the two quasi-hemispheres is near the 150°W meridian (from PKP-Bdiff observations), but possibly rotated toward a NW-SE orientation, from PKP-Cdiff. Alternately, a velocity heterogeneity could be present here, in agreement with the previously reported PKIKP vs. PKPBC observations. Assuming the conventional definition for the IC quasi-hemispheres (i.e., the QEH between 0° and 180°E, and the QWH between 0° and 180°W), the quasi-Eastern hemisphere exhibits perturbations of (+1.17 ± 0.04) % (from PKIKP-PKP-Bdiff) and (+0.19 ± 0.01) % (from PKIKP-PKP-Cdiff). The corresponding perturbations in the quasi-Western hemisphere are of (-0.06 ± 0.06) % and (-0.19 ± 0.02) %, respectively. An anomalous IC zone beneath the Indian Ocean is not conspicuous in our PKIKP-PKP-Cdiff observations. Beneath the North Atlantic, the separation between the IC quasi-hemispheres appears to be located between 60°W and 30°W from the PKP-Bdiff observations, but it remains unresolved from the PKP-Cdiff data, due to scarce observations here.

  3. Hurricane Season

    Institute of Scientific and Technical Information of China (English)

    JENNIFER; JETT

    2008-01-01

    Three years after Katrina,the United States isdetermined not to repeatits mistakes This year has seen an unusually activeand deadly hurricane season, asstorms line up in the Atlantic Oceanto pummel the Caribbean and UnitedStates coastline.

  4. Effects of Hurricane Katrina on the forest structure of taxodium distichum swamps of the Gulf Coast, USA

    Science.gov (United States)

    Middleton, B.A.

    2009-01-01

    Hurricane Katrina pushed mixed Taxodium distichum forests toward a dominance of Taxodium distichum (baldcypress) and Nyssa aquatica (water tupelo) because these species had lower levels of susceptibility to wind damage than other woody species. This study documents the volume of dead versus live material of woody trees and shrubs of T. distichum swamps following Hurricane Katrina along the Gulf Coast of Mississippi and Louisiana. Pearl River Wildlife Management Area near Canton, Mississippi had the highest winds of the study areas, and these forests were located in the northeast quadrant of Hurricane Katrina (sustained wind 151 kph (94 mph)). Jean Lafitte National Historical Park and Preserve south of New Orleans had medium to high winds (sustained winds 111 kph (69 mph) at the New Orleans lakefront). Cat Island National Wildlife Refuge had a lower level of winds and was positioned on the western edge of the storm. The forests at Pearl River and to a lesser extent at Jean Lafitte had the highest amount of structural damage in the study. For Cat Island, Jean Lafitte, and Pearl River, the total volume of dead material (debris) was 50, 80, and 370 m3 ha-1, respectively. The ratio of dead to live volume was 0.010, 0.082, and 0.039, respectively. For both of the dominant species, T. distichum and N. aquatica, the percentage of dead to live volume was less than 1. Subdominant species including Acer rubrum, Liquidambar styraciflua, Quercus lyrata, and Quercus nigra were more damaged by the storm at both Pearl River and Jean Lafitte. Only branches were damaged by Hurricane Katrina at Cat Island. Shrubs such as Morella cerifera, Euonymous sp., and Vaccinium sp. were often killed by the storm, while other species such as Cephalanthus occidentalis, Forestiera acuminata, and Cornus florida were not killed. Despite the fact that Hurricane Katrina was a Category 3 storm and struck Pearl River and Jean Lafitte fairly directly, dominant species of the T. distichum swamps were

  5. 三维变分同化机载雷达资料对飓风预报的影响研究--2012年Isaac试验%A Study of the Impact of Airborne Radar Data Assimilated by 3DVar on the Prediction of Hurricane-Isaac 2012

    Institute of Scientific and Technical Information of China (English)

    陆续; 马旭林; 王旭光

    2015-01-01

    随着气旋内部资料(Inner core data)在热带气旋预报中的使用,其重要性逐渐受到人们越来越多的关注。为了研究该资料中尾部机载雷达(Tail Doppler Radar,TDR)资料在业务系统中的应用效果,本文利用2012年飓风等级热带气旋Isaac期间的TDR资料,采用业务HWRF(Weather Research and Forecasting model for Hurricane)数值模式与业务GSI(Grid-point Statistical Interpolation system)三维变分同化(Three-Dimensional Variational Data Assimilation,3DVar)系统对TDR资料进行了同化,展开了一系列预报试验,并对其效果进行了分析和研究。结果表明与HWRF的业务预报相比,GSI系统同化TDR资料后对热带气旋的路径和强度预报有明显改进;但其同化效果同时也表明业务三维变分中的静态背景误差协方差在TDR资料的应用中仍需要进一步的改进。%Given the increasingly important role of inner-core data in tropical cyclone (TC) forecasting, the present paper investigates the impact of assimilating Tail Doppler Radar (TDR) data on the prediction of hurricanes. A series of experiments are conducted using the operational Weather Research and Forecasting model for Hurricane (HWRF) and grid-point statistical interpolation (GSI) 3D variational (3DVar) system for Hurricane Isaac (2012). It is found that the assimilation of TDR data can correct the storm center to a better position compared to without TDR assimilation. Furthermore, the better inner-core structures in the results of the experiments that assimilated the TDR data have a positive impact on the intensity forecasts. In general, the TDR data improve the TC track and intensity forecast compared to the official forecasts from the operational HWRF, and the forecasts without assimilating the TDR data. The study also suggests that further reducing the background error covariances to be consistent with the dynamical and thermodynamical structures of the

  6. Thermal Equation of State of Fe7C3 by Single Crystal X-ray Diffraction with Implications for Carbon in the Inner Core

    Science.gov (United States)

    Lai, X.; Chen, B.; Zhu, F.; Liu, J.; Hu, Y.; Dera, P.; Zhang, D.

    2016-12-01

    Carbon is one of the principle candidates for the light elements in Earth's core partly due to its high cosmic abundance and high solubility in Fe-Ni alloy [1,2]. Its alloys with iron (Fe), iron carbides, are also found in reducing environment in the Earth's mantle [3]. Eckstrom-Adcock carbide Fe7C3 is likely to be the first phase to solidify from Fe-C melt under core conditions, and has thus been proposed to be an inner core candidate [4]. The crystal structure of Fe7C3, however, remains controversial and its thermoelastic properties, crucial for extrapolating the room-temperature mineral physics data to high temperature conditions, were rarely investigated approaching core pressures. In this study, we performed synchrotron single-crystal X-ray diffraction (XRD) measurements using externally-heated diamond anvil cells and determined the crystal structure, lattice parameters and atomic positions of Fe7C3 up to 75 GPa and 800 K. The ambient pressure unit cell volume (V0), bulk modulus (K0) and its first derivative (K0') at 300 K were determined by fitting the third-order Birch-Murnaghan equation of state. The pressure-volume-temperature data set for Fe7C3 could be well represented by a Mie-Grüneisen-Debye thermal equation of state. We found that the c/a ratio of Fe7C3 decreases continuously up to 45 GPa and increases abruptly at around 55 GPa at 300K, probably due to the high-spin to low-spin transition. The thermal expansion of c axis is notably larger than other axes. The determined thermoelastic property of Fe7C3 will permit stringent test of a Fe-C inner core compositional model. References: [1] Wood, Bernard J. Earth Planet. Sci. Lett. 117.3 (1993): 593-607. [2] Wood, Bernard J., Jie Li, and Anat Shahar. Rev. Mineral. Geochem. 75 (2013): 231-250. [3] Kaminsky, Felix V., and Richard Wirth. Can. Mineral. 49.2 (2011): 555-572. [4] Fei, Yingwei, and Eli Brosh. Earth Planet. Sci. Lett. 408 (2014): 155-162.

  7. Influence of hurricane wind field in the structure of directional wave spectra.

    Science.gov (United States)

    Esquivel-Trava, Bernardo; García-Nava, Hector; Osuna, Pedro; Ocampo-Torres, Francisco J.

    2017-04-01

    Three numerical experiments using the spectral wave prediction model SWAN were carried out to gain insight into the mechanism that controls the directional and frequency distributions of hurricane wave energy. One particular objective is to evaluate the effect of the translation speed of the hurricane and the presence of concentric eye walls, on both the wave growth process and the shape of the directional wave spectrum. The HRD wind field of Hurricane Dean on August 20 at 7:30 was propagated at two different velocities (5 and 10 m/s). An idealized concentric eye wall (a Gaussian function that evolve in time along a path in the form of an Archimedean spiral) was imposed to the wind field. The white-capping formulation of Westhuysen et al. (2007) was selected. The wave model represents fairly well the directionality of the energy and the shape of the directional spectra in the hurricane domain. The model results indicate that the forward movement of the storm influences the development of the waves, consistent with field observations. Additionally the same experiments were carried out using the Wave Watch III model with the source terms formulation proposed by Ardhuin et al., 2010, with the aim of making comparisons between the physical processes that represent each formulation, and the latest results will be addressed. References Ardhuin, F., Rogers, E., Babanin, A. V., Filipot, J.-F., Magne, R., Roland, A., van der Westhuysen, A., et al. (2010). Semiempirical Dissipation Source Functions for Ocean Waves. Part I: Definition, Calibration, and Validation. Journal of Physical Oceanography, 40(9), 1917-1941. doi:10.1175/2010JPO4324.1 Van der Westhuysen, A. J., Zijlema, M., & Battjes, J. A. (2007). Nonlinear saturation-based whitecapping dissipation in SWAN for deep and shallow water. Coast. Eng., 54(2), 151-170. doi:10.1016/j.coastaleng.2006.08.006

  8. The influence of an inner core, tides, and precession of the pericenter on the orientation of the rotation axis of Mercury

    Science.gov (United States)

    Baland, Rose-Marie; Yseboodt, Marie; Van Hoolst, Tim; Rivoldini, Attilio

    2016-10-01

    Mercury's spin axis occupies the Cassini state 1, in which the orbit normal and spin axis precess together with a long period of about 300 000 years. An accurate model of the Cassini state is needed to get a reliable estimate of its polar moment of inertia from the measured orientation of its spin axis. The polar moment of inertia provides a strong constraint on the interior structure. For long, it has been assumed that Mercury precesses as a solid body, meaning that the estimate of the polar moment of inertia may be inaccurate. Recently, there has been renewed interest for the topic, because of the recent determination of Mercury's rotation state (Earth-based radar observations, MESSENGER data), as well as the possibility of future more accurate measurements with the BepiColombo mission.Here, we revisit the influence of the liquid outer core, solid inner core, and precession of the pericenter (period of about 127 000 years). Previous studies have concluded that those effects may have an influence above or up to about an order of magnitude below the present uncertainty on the obliquity. We consider three-layer interior models with a mantle (including the crust), a liquid outer core and a solid inner core. Those models are constrained by the mass, radius, second-degree gravity field coefficients and libration amplitude. We adapt to Mercury a Cassini state model previously developed for synchronous satellites, in which we express the spin axis motion in a frame based on the Laplace plane. We take into account the solar gravitational torque exerted on each layer, the internal gravitational torques between the internal layers and the pressure torques as well as the dissipative viscous torques exerted at the interfaces. We reassess the effect of tidal periodic deformations on the torques, currently thought to be two orders of magnitude below the present uncertainty on the spin orientation determination. Finally, we use the current rotation data to constrain Mercury

  9. The Gravity Field Variation Caused by Inner Core Super Rotation%内核超速旋转引起的重力场变化

    Institute of Scientific and Technical Information of China (English)

    陈巍; 申文斌; 韩建成

    2008-01-01

    Due to the super rotation of the Earth's inner core,the tilted figure axis of the inner core would progress with re-spect to the mantle and thus cause the variation of the Earth's external gravity field.This paper improves the present model of the gravity field variation caused by the inner core super rotation.Under the assumption that the inner core is a stratifying ellipsoid whose density function is fitted out from PREM and the super rotation rate is 0.27~0.53°/yr,calculations show that the global temporal variations on the Earth's surface have a maximum value of about 0.79~1.54×103 μGal and a global av-erage intensity of about 0.45~0.89×103 μGal in the whole year of 2007,which is beyond the accuracy of the present gra-vimetry and even the super conducting gravimeter data.However,both the gravity variations at Beijing and Wuhan vary like sine variables with maximal variations around 0.33 μGal and 0.29 μGal,respectively,in one cycle.Thus,continuous gravity measurements for one or two decades might be able to detect the differential motion of the inner core.

  10. Hurricane damage assessment for residential construction considering the non-stationarity in hurricane intensity and frequency

    Institute of Scientific and Technical Information of China (English)

    WANG Cao; LI Quanwang; PANG Long; ZOU Aming; ZHANG Long

    2016-01-01

    Natural hazards such as hurricanes may cause extensive economic losses and social disruption for civil structures and infrastructures in coastal areas, implying the importance of understanding the construction performance subjected to hurricanes and assessing the hurricane damages properly. The intensity and frequency of hurricanes have been reported to change with time due to the potential impact of climate change. In this paper, a probability-based model of hurricane damage assessment for coastal constructions is proposed taking into account the non-stationarity in hurricane intensity and frequency. The non-homogeneous Poisson process is employed to model the non-stationarity in hurricane occurrence while the non-stationarity in hurricane intensity is reflected by the time-variant statistical parameters (e.g., mean value and/or standard deviation), with which the mean value and variation of the cumulative hurricane damage are evaluated explicitly. The Miami-Dade County, Florida, USA, is chosen to illustrate the hurricane damage assessment method proposed in this paper. The role of non-stationarity in hurricane intensity and occurrence rate due to climate change in hurricane damage is investigated using some representative changing patterns of hurricane parameters.

  11. Detection of the translational oscillations of the Earth's solid inner core based on the international superconducting gravimeter observations

    Institute of Scientific and Technical Information of China (English)

    SUN Heping; XU Jianqiao; B.Ducarme

    2004-01-01

    Based on the 21 series of the high precision tidal gravity observations recorded using superconducting gravimeters (SG) at 14 stations distributed globally (in totally about 86 years), the translational oscillations of the Earth's solid inner core (ESIC) is detected in this paper. All observations are divided into two groups with G-Ⅰ group (8 relatively longer observational series) and G-Ⅱ group (13 relatively shorter observational series). The detailed corrections to minute original observations for each station are carried out, the error data due to the earthquakes, power supply impulses and some perturbations as change in atmospheric pressure and so on are carefully deleted for the first step, the gravity residuals are obtained after removing further synthetic tidal gravity signals. The Fast Fourier Transform analysis is carried out for each residual series, the estimations of the product spectral densities in the sub-tidal band are obtained by using a multi-station staking technique. The 8 common peaks are found after further removing the remaining frequency dependent pressure signals. The eigenperiods, quality factors and resonant strengths for these peaks are simulated. The numerical results show that the discrepancies of the eigenperiods for 3 of 8 peaks, compared to those of theoretical computation given by Smith, are only 0.4%, -0.4% and 1.0%. This coincidence signifies that the dynamical phenomenon of the Earth's solid inner core can be detected by using high precision ground gravity observations. The reliability of the numerical computation is also checked, the spectral peak splitting phenomenon induced by Earth's rotation and ellipticity is preliminary discussed in this paper.

  12. Female hurricanes are deadlier than male hurricanes.

    Science.gov (United States)

    Jung, Kiju; Shavitt, Sharon; Viswanathan, Madhu; Hilbe, Joseph M

    2014-06-17

    Do people judge hurricane risks in the context of gender-based expectations? We use more than six decades of death rates from US hurricanes to show that feminine-named hurricanes cause significantly more deaths than do masculine-named hurricanes. Laboratory experiments indicate that this is because hurricane names lead to gender-based expectations about severity and this, in turn, guides respondents' preparedness to take protective action. This finding indicates an unfortunate and unintended consequence of the gendered naming of hurricanes, with important implications for policymakers, media practitioners, and the general public concerning hurricane communication and preparedness.

  13. Development and evolution of convective bursts in WRF simulations of hurricanes Dean (2007) and Bill (2009)

    Science.gov (United States)

    Hazelton, Andrew Todd

    Understanding and predicting the inner-core structure and intensity change of tropical cyclones (TCs) remains one of the biggest challenges in tropical meteorology. This study addresses this challenge by investigating the formation, structure, and intensity changes resulting from localized strong updrafts in TCs known as convective bursts (CBs). The evolution of CBs are analyzed in high-resolution simulations of two hurricanes (Dean 2007 and Bill 2009) using the Weather Research and Forecasting (WRF) model. The simulations are able to capture the observed track and peak intensity of the TCs. With Dean, there is a slight lag between the simulated intensification and actual intensification, and the extreme rate of RI is not fully captured. However, the cycle of intensification, weakening, and re-intensification observed in both TCs is captured in the simulations, and appears to be due to a combination of internal dynamics and the surrounding environmental conditions. CBs are identified based on the 99th percentile of eyewall vertical velocity (over the layer from z = 6-12 km) in each simulation (8.4 m s-1 for Dean, 5.4 m s-1 for Bill). The highest density of CBs is found in the downshear-left quadrant, consistent with prior studies. The structure of the CBs is analyzed by comparing r-z composites of azimuths with CBs and azimuths without CBs, using composite figures and statistical comparisons. The CB composites show stronger radial inflow in the lowest 0-2 km, and stronger radial outflow from the eye to the eyewall in the 2-4 km layer. The CB composites also have stronger low-level vorticity than the non-CBs, potentially due to eyewall mesovortices. The analysis of individual CBs also confirms the importance of the eye-eyewall exchange in CB development, potentially by providing buoyancy, as parcel trajectories show that many parcels are flung outward from the eye and rapidly ascend in the CBs, with as much as 500 J/kg of CAPE along the parcel path. In addition, the

  14. Examination of Hurricane Sandy's (2012 structure and intensity evolution from full-field and anomaly-field analyses

    Directory of Open Access Journals (Sweden)

    Wei-Hong Qian

    2016-08-01

    Full Text Available An anomaly-based field analysis approach and a set of simple beta-advection models (BAMs have been used to examine the structure evolution and unusual left turn of Hurricane Sandy (2012 before it made the landfall and caused severe damage along the eastern US coast. Results show that the anomaly-based analysis approach can clearly reveal Sandy's structure evolution, including its interaction with other synoptic-scale systems as well as the intensification and extratropical transition (ET processes. During its lifetime, Sandy experienced two consecutive periods of intensification caused by the merging of anomalous vortices on 27 and 29 October. The unusual left turn and the ET process prior to the landfall are respectively influenced by an anomalous anticyclone to the northeast and an anomalous cold vortex at the 300–850 hPa layer to the northwest, which is confirmed by the experiments using the generalised BAM.

  15. Seismic anisotropy; a window on how the Earth works: multiple mechanisms and sites, from shallow mantle to inner core

    Science.gov (United States)

    Osmaston, Miles

    2013-04-01

    Since the seismic anisotropy (SA) in the uppermost oceanic mantle was discovered [1] and attributed to the shearing of olivine by an MOR-divergent flow velocity gradient, rheological mobility interpretations of this type have dominated studies of SA there and elsewhere in the Earth. Here I describe two other SA-generating mechanisms. I will reason that one of these, the anisotropic crystallization from melt, bids fair largely to replace the shearing one and be present in even larger volumes of the Earth, both within its outer 100km and in the Inner Core. The other, the layered deposition of disparate substances, offers to explain the ULVZs and SA in D''. We start with the Upper Mantle. New constraints on its rheological properties and dynamical behaviour have come from two directions. Firstly, contrary to the seismologists' rule-book, the oceanic LVZ is no longer to be thought of as mobile because the presence of interstitial melt strips out the water-weakening of the mineral structure [2, 3]. So we require a substitute for the divergent-flow model for MORs. In fact it also has three other, apparently unrecognized, dynamical inconsistencies. One of these [4] is that there are in the record many rapid changes of spreading rate and direction, and ridge jumps. This cannot happen with a process driven by slow-to-change body forces. Secondly, during the past decade, my work on the global dynamics for the past 150Ma (I will show examples) has shown [4 - 7] that the tectospheres of cratons must extend to very close to the bottom of the upper mantle. And that East Antarctica's 'keel' must actually reach it, because its CW rotation [7] suggests it has been picking up an electromagnetic torque from the CMB via the lower mantle. Xenoliths suggest that the reason for this downwards extent of 'keels' is the same as [3]. To meet these two sets of constraints I will demonstrate my now not-so-new MOR model, which has a narrow, wall-accreting subaxial crack. Among its many features

  16. Hurricane Resource Reel

    Data.gov (United States)

    National Aeronautics and Space Administration — This Reel Includes the Following Sections TRT 50:10 Hurricane Overviews 1:02; Hurricane Arthur 15:07; Cyclone Pam 19:48; Typhoon Hagupit 21:27; Hurricane Bertha...

  17. Hurricane Evacuation Routes

    Data.gov (United States)

    Department of Homeland Security — Hurricane Evacuation Routes in the United States A hurricane evacuation route is a designated route used to direct traffic inland in case of a hurricane threat. This...

  18. Constraints on Earth’s inner core composition inferred from measurements of the sound velocity of hcp-iron in extreme conditions

    Science.gov (United States)

    Sakamaki, Tatsuya; Ohtani, Eiji; Fukui, Hiroshi; Kamada, Seiji; Takahashi, Suguru; Sakairi, Takanori; Takahata, Akihiro; Sakai, Takeshi; Tsutsui, Satoshi; Ishikawa, Daisuke; Shiraishi, Rei; Seto, Yusuke; Tsuchiya, Taku; Baron, Alfred Q. R.

    2016-01-01

    Hexagonal close-packed iron (hcp-Fe) is a main component of Earth’s inner core. The difference in density between hcp-Fe and the inner core in the Preliminary Reference Earth Model (PREM) shows a density deficit, which implies an existence of light elements in the core. Sound velocities then provide an important constraint on the amount and kind of light elements in the core. Although seismological observations provide density–sound velocity data of Earth’s core, there are few measurements in controlled laboratory conditions for comparison. We report the compressional sound velocity (VP) of hcp-Fe up to 163 GPa and 3000 K using inelastic x-ray scattering from a laser-heated sample in a diamond anvil cell. We propose a new high-temperature Birch’s law for hcp-Fe, which gives us the VP of pure hcp-Fe up to core conditions. We find that Earth’s inner core has a 4 to 5% smaller density and a 4 to 10% smaller VP than hcp-Fe. Our results demonstrate that components other than Fe in Earth’s core are required to explain Earth’s core density and velocity deficits compared to hcp-Fe. Assuming that the temperature effects on iron alloys are the same as those on hcp-Fe, we narrow down light elements in the inner core in terms of the velocity deficit. Hydrogen is a good candidate; thus, Earth’s core may be a hidden hydrogen reservoir. Silicon and sulfur are also possible candidates and could show good agreement with PREM if we consider the presence of some melt in the inner core, anelasticity, and/or a premelting effect. PMID:26933678

  19. Hurricane Imaging Radiometer (HIRAD) Wind Speed Retrieval Assessment with Dropsondes

    Science.gov (United States)

    Cecil, Daniel J.; Biswas, Sayak K.

    2017-01-01

    Map surface wind speed over wide swath (approximately 50-60 km, for aircraft greater than FL600) in hurricanes. Provide research data for understanding hurricane structure, and intensity change. Enable improved forecasts, warnings, and decision support.

  20. Can We Tell the Inner Core Size and the Heat Flow Pattern inside a Planet from the Observed Magnetic Field?

    Science.gov (United States)

    Cao, H.; Russell, C. T.; Wicht, J.; Christensen, U. R.

    2012-09-01

    Several distinct features of Saturn's magnetic field have been revealed in a recent study based on in-situ magnetic field measurements made by the Cassini spacecraft [1]. The field at the dynamo surface is found to be strongly concentrated near the spin-poles with little hemispherical asymmetry. This field geometry corresponds to a zig-zag shape magnetic spectrum with pronounced odd degree terms and all odd degree magnetic moments possess the same sign ( , and all be positive in this case). This is in contrast to the field properties at the outer core surface of the Earth, where the field near the spinpoles is at a relative minimum compared to field at mid-latitude (see Fig. 1). An anticyclonic polar vortex with upwelling flow inside the tangent cylinder (the tangent cylinder is an imaginary cylinder parallel to the spin axis and tangent to the inner core surface at the equator) has been inferred at the Earth's core surface from geomagnetic secular variation analyses [2]. The associated advective transport of magnetic field is like responsible for the typical minimum or inverse geomagnetic field at high latitudes and the pronounced flux patches at midlatitudes. This feature is also frequently found in convectively driven geodynamo models [3].

  1. The Hurricane and Its Impact

    Science.gov (United States)

    Burpee, Robert W.

    Recent population increases in coastal regions of the tropics and subtropics have greatly enhanced man's vulnerability to tropical cyclones. Thus, this book on hurricanes by Robert H. Simpson and Herbert Riehl, two of the leading contributors to hurricane research during the last 35 years, comes along when people of differing backgrounds want to learn more about hurricanes. In the 20 years since Dunn and Miller published Atlantic Hurricanes, technical advances in weather satellites, computer modeling and data processing, and research aircraft have substantially increased the tropical meteorologist's understanding of hurricane structure and dynamics. During this same time, field experiments have led to detailed knowledge of the atmospheric environment within which tropical cyclones are initiated. The authors have attempted to describe many aspects of hurricanes for readers that range from students of meteorology to those concerned with planning for natural hazards in the coastal zone. Because Simpson and Riehl have addressed such a wide audience, many readers with a knowledge of atmospheric science will find that the book is overly descriptive, while readers without some background in physics will find it is too technical.

  2. The paleomagnetism of single silicate crystals: Recording geomagnetic field strength during mixed polarity intervals, superchrons, and inner core growth

    Science.gov (United States)

    Tarduno, J. A.; Cottrell, R. D.; Smirnov, A. V.

    2006-03-01

    during times of moderate (10 reversals/million years) reversal occurrence suggest a weaker and more variable field. These paleointensity data, together with a consideration of paleomagnetic directions, suggest that geomagnetic reversals, field morphology, secular variation, and intensity are related. The linkages over tens of millions of years imply a lower mantle control on the geodynamo. On even longer timescales the magnetization held by plagioclase and other silicate crystals can be used to investigate the Proterozoic and Archean geomagnetic field during the onset of growth of the solid inner core. Data from plagioclase crystals separated from mafic dikes, together with directional data from whole rocks, indicate a dipole-dominated field similar to that of the modern, 2.5-2.7 billion years ago. Older Archean rocks are of great interest for paleomagnetic and paleointensity investigations because they may record a time when the compositionally driven convection of the modern dynamo may not have been operating and a solid inner core did not play its current role in controlling the geometry of outer core flow. Most rocks of this age have been affected by low-grade metamorphism; investigations using single silicate grains provide arguably our best hope of seeing through secondary geologic events and reading the early history of the geodynamo. Absolute paleointensity measurements of the oldest rocks on the planet will require the further development of methods to investigate silicate crystals with exsolved magnetic minerals that address the uncertainties posed by thermocrystallization remanent magnetization, anisotropy, and slow cooling. Fortunately, prior work in rock magnetism, together with advances in analytical equipment and techniques, provides a solid foundation from which these frontier issues can be approached.

  3. 77 FR 74341 - Establishing the Hurricane Sandy Rebuilding Task Force

    Science.gov (United States)

    2012-12-14

    ... the Hurricane Sandy Rebuilding Task Force By the authority vested in me as President by the.... Hurricane Sandy made landfall on October 29, 2012, resulting in major flooding, extensive structural damage... assist the affected region. A disaster of Hurricane Sandy's magnitude merits a comprehensive...

  4. Constraints on grain size and stable iron phases in the uppermost Inner Core from multiple scattering modeling of seismic velocity and attenuation

    CERN Document Server

    Calvet, Marie

    2008-01-01

    We propose to model the uppermost inner core as an aggregate of randomly oriented anisotropic ``patches''. A patch is defined as an assemblage of a possibly large number of crystals with identically oriented crystallographic axes. This simple model accounts for the observed velocity isotropy of short period body waves, and offers a reasonable physical interpretation for the scatterers detected at the top of the inner core. From rigorous multiple scattering modeling of seismic wave propagation through the aggregate, we obtain strong constraints on both the size and the elastic constants of iron patches. We perform a systematic search for iron models compatible with measured seismic velocities and attenuations. An iron model is characterized by its symmetry (cubic or hexagonal), elastic constants, and patch size. Independent of the crystal symmetry, we infer a most likely size of patch of the order of 400 m. Recent {\\it bcc} iron models from the literature are in very good agreement with the most probable elast...

  5. Satellite sar detection of hurricane helene (2006)

    DEFF Research Database (Denmark)

    Ju, Lian; Cheng, Yongcun; Xu, Qing;

    2013-01-01

    In this paper, the wind structure of hurricane Helene (2006) over the Atlantic Ocean is investigated from a C-band RADARSAT-1 synthetic aperture radar (SAR) image acquired on 20 September 2006. First, the characteristics, e.g., the center, scale and area of the hurricane eye (HE) are determined...

  6. Planetary Lithosphere-Outer Core-Inner Core-Mantle Coupled Evolution Over the Entire Age of the Solar System

    Science.gov (United States)

    Tackley, P. J.; Nakagawa, T.; Louro Lourenço, D. J.; Rozel, A.

    2016-12-01

    the start of long-term evolution to be particularly high. Considering this as well as the difficulties mentioned earlier it is difficult to drive the geodynamo prior to inner core appearance by purely thermal means, making alternative paradigms appealing.

  7. 2005 Atlantic Hurricanes Poster

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The 2005 Atlantic Hurricanes poster features high quality satellite images of 15 hurricanes which formed in the Atlantic Basin (includes Gulf of Mexico and Caribbean...

  8. Hurricane Gustav Poster

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Hurricane Gustav poster. Multi-spectral image from NOAA-17 shows Hurricane Gustav having made landfall along the Louisiana coastline. Poster size is 36"x27"

  9. Hurricane Ike Poster

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Hurricane Ike poster. Multi-spectral image from NOAA-15 shows Hurricane Ike in the Gulf of Mexico heading toward Galveston Island, Texas. Poster size is 36"x27".

  10. 2004 Landfalling Hurricanes Poster

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The 2004 U.S. Landfalling Hurricanes poster is a special edition poster which contains two sets of images of Hurricanes Charley, Frances, Ivan, and Jeanne, created...

  11. Hurricane Sandy and earthquakes

    OpenAIRE

    MAVASHEV BORIS; MAVASHEV IGOR

    2013-01-01

    Submit for consideration the connection between formation of a hurricane Sandy and earthquakes. As a rule, weather anomalies precede and accompany earthquakes. The hurricane Sandy emerged 2 days prior to strong earthquakes that occurred in the area. And the trajectory of the hurricane Sandy matched the epicenter of the earthquakes. Possibility of early prediction of natural disasters will minimize the moral and material damage.

  12. Alternative designs for hurricane protection systems and building structures in New Orleans

    NARCIS (Netherlands)

    Bijlsma, E.; Rolvink, A.; Veenendaal, D.; Van de Waal, R.J.

    2006-01-01

    First the demands and the boundary conditions are set for the complete protection system; after that the protection system will be split in the three subsections (primary: peripheral levees, secondary: canal levees and watermanagement and tertiary: structural integrety housing). For each of these

  13. Factor Structure of the Acute Stress Disorder Scale in a Sample of Hurricane Katrina Evacuees

    Science.gov (United States)

    Edmondson, Donald; Mills, Mary Alice; Park, Crystal L.

    2010-01-01

    Acute stress disorder (ASD) is a poorly understood and controversial diagnosis (A. G. Harvey & R. A. Bryant, 2002). The present study used confirmatory factor analysis (CFA) to test the factor structure of the most widely used self-report measure of ASD, the Acute Stress Disorder Scale (R. A. Bryant, M. L. Moulds, & R. M. Guthrie, 2000),…

  14. Comments on Symmetric and Asymmetric Structures of Hurricane Boundary Layer in Coupled Atmosphere-Wave-Ocean Models and Observations

    Science.gov (United States)

    2014-07-01

    author address: Dr. Jun Zhang, NOAA/AOML/ Hurricane Research Division with University of Miami/ CIMAS , 4301 Rickenbacker Causeway, Miami, FL 33149. E...suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis...S) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Naval Postgraduate School

  15. Satellite sar detection of hurricane helene (2006)

    DEFF Research Database (Denmark)

    Ju, Lian; Cheng, Yongcun; Xu, Qing

    2013-01-01

    In this paper, the wind structure of hurricane Helene (2006) over the Atlantic Ocean is investigated from a C-band RADARSAT-1 synthetic aperture radar (SAR) image acquired on 20 September 2006. First, the characteristics, e.g., the center, scale and area of the hurricane eye (HE) are determined....... There is a good agreement between the SAR-estimated HE center location and the best track data from the National Hurricane Center. The wind speeds at 10 m above the ocean surface are also retrieved from the SAR data using the geophysical model function (GMF), CMOD5, and compared with in situ wind speed...... observations from the stepped frequency microwave radiometer (SFMR) on NOAA P3 aircraft. All the results show the capability of hurricane monitoring by satellite SAR. Copyright © 2013 by the International Society of Offshore and Polar Engineers (ISOPE)....

  16. Simulation of hurricane response to suppression of warm rain by sub-micron aerosols

    National Research Council Canada - National Science Library

    Rosenfeld, D; Khain, A; Lynn, B; Woodley, W. L

    2007-01-01

    ...). The possible impact of seeding of clouds with submicron cloud condensation nuclei (CCN) on hurricane structure and intensity as measured by nearly halving of the area covered by hurricane force winds was simulated by "turning...

  17. Forced nutations of the earth: Influence of inner core dynamics. I - Theory. II - Numerical results and comparisons. III - Very long interferometry data analysis

    Science.gov (United States)

    Mathews, P. M.; Buffett, Bruce A.; Herring, Thomas A.; Shapiro, Irwin I.

    1991-01-01

    A treatment is presented of the nutation problem for an oceanless, elastic, spheroidally stratified earth, with the dynamical role of the inner core explicitly included in the formulation. Solving the enlarged system of equations shows that a new almost diurnal eigenfrequency emerges. A rough estimate places it not far from the prograde annual tidal excitation frequency, so that possible resonance effects on nutation amplitudes need careful consideration. Tables are provided that exhibit the sensitivities of various relevant quantities, the eigenfrequencies and the coefficients which appear in the resonance expansion, as well as the nutation amplitudes at important tidal frequencies, to possible errors in the earth parameters which enter the theory set forth. Finally, the analysis of 798 VLBI experiments performed between July 1980 and February 1989 and the determination from this analysis of corrections to selected coefficients in the International Astronomical Union 1980 theory of the nutations of the earth are discussed.

  18. Recovering from Hurricane Katrina

    Science.gov (United States)

    Coleman, Nadine

    2006-01-01

    The Gulf Coast region suffered an unusually severe hurricane season in 2005: Hurricane Katrina (August 28-29, 2005) devastated much of southern Mississippi and Louisiana. Approximately 2,700 licensed early care and education facilities in those states and in Alabama were affected by Katrina, in addition to an unknown number of family child care…

  19. Forecasting hurricane impact on coastal topography: Hurricane Ike

    Science.gov (United States)

    Plant, Nathaniel G.; Stockdon, Hilary F.; Sallenger,, Asbury H.; Turco, Michael J.; East, Jeffery W.; Taylor, Arthur A.; Shaffer, Wilson A.

    2010-01-01

    Extreme storms can have a profound impact on coastal topography and thus on ecosystems and human-built structures within coastal regions. For instance, landfalls of several recent major hurricanes have caused significant changes to the U.S. coastline, particularly along the Gulf of Mexico. Some of these hurricanes (e.g., Ivan in 2004, Katrina and Rita in 2005, and Gustav and Ike in 2008) led to shoreline position changes of about 100 meters. Sand dunes, which protect the coast from waves and surge, eroded, losing several meters of elevation in the course of a single storm. Observations during these events raise the question of how storm-related changes affect the future vulnerability of a coast.

  20. Hurricane Katrina Wind Investigation Report

    Energy Technology Data Exchange (ETDEWEB)

    Desjarlais, A. O.

    2007-08-15

    ; (2) Updated and improved application guidelines and manuals from associations and manufacturers; (3) Launched certified product installer programs; and (4) Submitted building code changes to improve product installation. Estimated wind speeds at the damage locations came from simulated hurricane models prepared by Applied Research Associates of Raleigh, North Carolina. A dynamic hurricane wind field model was calibrated to actual wind speeds measured at 12 inland and offshore stations. The maximum estimated peak gust wind speeds in Katrina were in the 120-130 mph range. Hurricane Katrina made landfall near Grand Isle, Louisiana, and traveled almost due north across the city of New Orleans. Hurricane winds hammered the coastline from Houma, Louisiana, to Pensacola, Florida. The severe flooding problems in New Orleans made it almost impossible for the investigating teams to function inside the city. Thus the WIP investigations were all conducted in areas east of the city. The six teams covered the coastal areas from Bay Saint Louis, Mississippi, on the west to Pascagoula, Mississippi, on the east. Six teams involving a total of 25 persons documented damage to both low slope and steep slope roofing systems. The teams collected specific information on each building examined, including type of structure (use or occupancy), wall construction, roof type, roof slope, building dimensions, roof deck, insulation, construction, and method of roof attachment. In addition, the teams noted terrain exposure and the estimated wind speeds at the building site from the Katrina wind speed map. With each team member assigned a specific duty, they described the damage in detail and illustrated important features with numerous color photos. Where possible, the points of damage initiation were identified and damage propagation described. Because the wind speeds in Katrina at landfall, where the investigations took place, were less than code-specified design speeds, one would expect roof

  1. Hurricane Katrina Wind Investigation Report

    Energy Technology Data Exchange (ETDEWEB)

    Desjarlais, A. O.

    2007-08-15

    ; (2) Updated and improved application guidelines and manuals from associations and manufacturers; (3) Launched certified product installer programs; and (4) Submitted building code changes to improve product installation. Estimated wind speeds at the damage locations came from simulated hurricane models prepared by Applied Research Associates of Raleigh, North Carolina. A dynamic hurricane wind field model was calibrated to actual wind speeds measured at 12 inland and offshore stations. The maximum estimated peak gust wind speeds in Katrina were in the 120-130 mph range. Hurricane Katrina made landfall near Grand Isle, Louisiana, and traveled almost due north across the city of New Orleans. Hurricane winds hammered the coastline from Houma, Louisiana, to Pensacola, Florida. The severe flooding problems in New Orleans made it almost impossible for the investigating teams to function inside the city. Thus the WIP investigations were all conducted in areas east of the city. The six teams covered the coastal areas from Bay Saint Louis, Mississippi, on the west to Pascagoula, Mississippi, on the east. Six teams involving a total of 25 persons documented damage to both low slope and steep slope roofing systems. The teams collected specific information on each building examined, including type of structure (use or occupancy), wall construction, roof type, roof slope, building dimensions, roof deck, insulation, construction, and method of roof attachment. In addition, the teams noted terrain exposure and the estimated wind speeds at the building site from the Katrina wind speed map. With each team member assigned a specific duty, they described the damage in detail and illustrated important features with numerous color photos. Where possible, the points of damage initiation were identified and damage propagation described. Because the wind speeds in Katrina at landfall, where the investigations took place, were less than code-specified design speeds, one would expect roof

  2. Hurricane Imaging Radiometer

    Science.gov (United States)

    Cecil, Daniel J.; Biswas, Sayak K.; James, Mark W.; Roberts, J. Brent; Jones, W. Linwood; Johnson, James; Farrar, Spencer; Sahawneh, Saleem; Ruf, Christopher S.; Morris, Mary; hide

    2014-01-01

    The Hurricane Imaging Radiometer (HIRAD) is a synthetic thinned array passive microwave radiometer designed to allow retrieval of surface wind speed in hurricanes, up through category five intensity. The retrieval technology follows the Stepped Frequency Microwave Radiometer (SFMR), which measures surface wind speed in hurricanes along a narrow strip beneath the aircraft. HIRAD maps wind speeds in a swath below the aircraft, about 50-60 km wide when flown in the lower stratosphere. HIRAD has flown in the NASA Genesis and Rapid Intensification Processes (GRIP) experiment in 2010 on a WB-57 aircraft, and on a Global Hawk unmanned aircraft system (UAS) in 2012 and 2013 as part of NASA's Hurricane and Severe Storms Sentinel (HS3) program. The GRIP program included flights over Hurricanes Earl and Karl (2010). The 2012 HS3 deployment did not include any hurricane flights for the UAS carrying HIRAD. The 2013 HS3 flights included one flight over the predecessor to TS Gabrielle, and one flight over Hurricane Ingrid. This presentation will describe the HIRAD instrument, its results from the 2010 and 2013 flights, and potential future developments.

  3. Hurricane! Coping With Disaster

    Science.gov (United States)

    Lifland, Jonathan

    A new AGU book, Hurricane! Coping With Disaster, analyzes the progress made in hurricane science and recounts how advances in the field have affected the public's and the scientific community's understanding of these storms. The book explores the evolution of hurricane study, from the catastrophic strike in Galveston, Texas in 1900—still the worst natural disaster in United States history—to today's satellite and aircraft observations that track a storm's progress and monitor its strength. In this issue, Eos talks with Robert Simpson, the books' senior editor.Simpson has studied severe storms for more than 60 years, including conducting one of the first research flights through a hurricane in 1945. He was the founding director of the (U.S.) National Hurricane Research Project and has served as director of the National Hurricane Center. In collaboration with Herbert Saffir, Simpson helped design and implement the Saffir/Simpson damage potential scale that is widely used to identify potential damage from hurricanes.

  4. Thermal equation of state of hcp-iron: Constraint on the density deficit of Earth's solid inner core: THERMAL EQUATION OF STATE OF HCP-IRON

    Energy Technology Data Exchange (ETDEWEB)

    Fei, Yingwei [Geophysical Laboratory, Carnegie Institution of Washington, Washington District of Columbia USA; Murphy, Caitlin [Geophysical Laboratory, Carnegie Institution of Washington, Washington District of Columbia USA; Shibazaki, Yuki [Geophysical Laboratory, Carnegie Institution of Washington, Washington District of Columbia USA; Now at Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai Japan; Shahar, Anat [Geophysical Laboratory, Carnegie Institution of Washington, Washington District of Columbia USA; Huang, Haijun [School of Sciences, Wuhan University of Technology, Wuhan China

    2016-07-04

    We conducted high-pressure experiments on hexagonal close packed iron (hcp-Fe) in MgO, NaCl, and Ne pressure-transmitting media and found general agreement among the experimental data at 300 K that yield the best fitted values of the bulk modulus K0 = 172.7(±1.4) GPa and its pressure derivative K0'= 4.79(±0.05) for hcp-Fe, using the third-order Birch-Murnaghan equation of state. Using the derived thermal pressures for hcp-Fe up to 100 GPa and 1800 K and previous shockwave Hugoniot data, we developed a thermal equation of state of hcp-Fe. The thermal equation of state of hcp-Fe is further used to calculate the densities of iron along adiabatic geotherms to define the density deficit of the inner core, which serves as the basis for developing quantitative composition models of the Earth's inner core. We determine the density deficit at the inner core boundary to be 3.6%, assuming an inner core boundary temperature of 6000 K.

  5. Analyzing Hurricane Sandy

    Science.gov (United States)

    Convertino, Angelyn; Meyer, Stephan; Edwards, Becca

    2015-03-01

    Post-tropical Storm Sandy underwent extratropical transition shortly before making landfall in southern New Jersey October 29 2012. Data from this system was compared with data from Hurricane Ike (2008) which represents a classic hurricane with a clear eye wall and symmetry after landfall. Storm Sandy collided with a low pressure system coming in from the north as the hurricane made landfall on the US East coast. This contributed to Storm Sandy acting as a non-typical hurricane when it made landfall. Time histories of wind speed and wind direction were generated from data provided by Texas Tech's StickNet probes for both storms. The NOAA Weather and Climate program were used to generate radar loops of reflectivity during the landfall for both storms; these loops were compared with time histories for both Ike and Sandy to identify a relationship between time series data and storm-scale features identified on radar.

  6. Cooperative Hurricane Network Obs

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Observations from the Cooperative Hurricane Reporting Network (CHURN), a special network of stations that provided observations when tropical cyclones approached the...

  7. Hurricane Katrina disaster diplomacy.

    Science.gov (United States)

    Kelman, Ilan

    2007-09-01

    Hurricane Katrina struck the United States at the end of August 2005. The consequent devastation appeared to be beyond the US government's ability to cope with and aid was offered by several states in varying degrees of conflict with the US. Hurricane Katrina therefore became a potential case study for 'disaster diplomacy', which examines how disaster-related activities do and do not yield diplomatic gains. A review of past disaster diplomacy work is provided. The literature's case studies are then categorised using a new typology: propinquity, aid relationship, level and purpose. Hurricane Katrina and its aftermath are then placed in the context of the US government's foreign policy, the international response to the disaster and the US government's reaction to these responses. The evidence presented is used to discuss the potential implications of Hurricane Katrina disaster diplomacy, indicating that factors other than disaster-related activities generally dominate diplomatic relations and foreign policy.

  8. Hurricane Matthew overwash extents

    Science.gov (United States)

    Doran, Kara; Long, Joseph W.; Birchler, Justin; Range, Ginger

    2017-01-01

    The National Assessment of Coastal Change Hazards project exists to understand and predict storm impacts to our nation's coastlines. This data defines the alongshore extent of overwash deposits attributed to coastal processes during Hurricane Matthew.

  9. Hurricane Katrina Water Sampling

    Science.gov (United States)

    Hurricane Katrina made landfall in August 2005, causing widespread devastation along the Gulf Coast of the United States. EPA emergency response personnel worked with FEMA and state and local agencies to respond to the emergencies throughout the Gulf.

  10. Hurricane Katrina Sediment Sampling

    Science.gov (United States)

    Hurricane Katrina made landfall in August 2005, causing widespread devastation along the Gulf Coast of the United States. EPA emergency response personnel worked with FEMA and state and local agencies to respond to the emergencies throughout the Gulf.

  11. Hurricane Katrina Soil Sampling

    Science.gov (United States)

    Hurricane Katrina made landfall in August 2005, causing widespread devastation along the Gulf Coast of the United States. EPA emergency response personnel worked with FEMA and state and local agencies to respond to the emergencies throughout the Gulf.

  12. Hurricane Katrina Water Sampling

    Data.gov (United States)

    U.S. Environmental Protection Agency — Hurricane Katrina made landfall in August 2005, causing widespread devastation along the Gulf Coast of the United States. EPA emergency response personnel worked...

  13. Hurricane Katrina Soil Sampling

    Data.gov (United States)

    U.S. Environmental Protection Agency — Hurricane Katrina made landfall in August 2005, causing widespread devastation along the Gulf Coast of the United States. EPA emergency response personnel worked...

  14. Hurricane Katrina Sediment Sampling

    Data.gov (United States)

    U.S. Environmental Protection Agency — Hurricane Katrina made landfall in August 2005, causing widespread devastation along the Gulf Coast of the United States. EPA emergency response personnel worked...

  15. Continental United States Hurricane Strikes

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Continental U.S. Hurricane Strikes Poster is our most popular poster which is updated annually. The poster includes all hurricanes that affected the U.S. since...

  16. Mechanisms for Secondary Eyewall Formation in Tropical Cyclones: A Case Study of Hurricane Katrina (2005)

    Science.gov (United States)

    Garcia-Rivera, J. M.; Lin, Y.

    2013-05-01

    The Weather Research and Forecast (WRF) model is used to simulate the last eyewall replacement cycle (ERC) of Hurricane Katrina (2005) just before it's landfall in the Louisiana coastline. In this study, we pursue a complete understanding of the physics behind the secondary eyewall formation (SEF) in tropical cyclones. The simulation results show the occurrence of the early stages of an ERC in the simulated storm just before landfall. This confirms that with the appropriate set of physics parameterization schemes, grid spacing and initial conditions, the numerical model is able to reproduce ERCs on certain tropical cyclones with no data assimilation or extra data inputs. Strong updrafts are observed to converge in a ring outside the primary eyewall of Hurricane Katrina (2005) suggesting SEF during that period. The increase of divergence outside the primary eyewall with an outer-ring of convergence forming above the boundary layer can be part of the mechanisms that lead to SEF. Also, potential vorticity (PV) field is analyzed for its possible relationship with the development of the secondary eyewall. This detailed study of the pre-ERC events in the inner-core of Hurricane Katrina can build the foundations for testing some of the existing hypotheses for the development of secondary eyewalls leading to new ideas behind their formation.

  17. Hurricane Katrina: A Teachable Moment

    Science.gov (United States)

    Bertrand, Peggy

    2009-01-01

    This article presents suggestions for integrating the phenomenon of hurricanes into the teaching of high school fluid mechanics. Students come to understand core science concepts in the context of their impact upon both the environment and human populations. Suggestions for using information about hurricanes, particularly Hurricane Katrina, in a…

  18. Hurricane Katrina: A Teachable Moment

    Science.gov (United States)

    Bertrand, Peggy

    2009-01-01

    This article presents suggestions for integrating the phenomenon of hurricanes into the teaching of high school fluid mechanics. Students come to understand core science concepts in the context of their impact upon both the environment and human populations. Suggestions for using information about hurricanes, particularly Hurricane Katrina, in a…

  19. On the relationship between hurricane cost and the integrated wind profile

    Science.gov (United States)

    Wang, S.; Toumi, R.

    2016-11-01

    It is challenging to identify metrics that best capture hurricane destructive potential and costs. Although it has been found that the sea surface temperature and vertical wind shear can both make considerable changes to the hurricane destructive potential metrics, it is still unknown which plays a more important role. Here we present a new method to reconstruct the historical wind structure of hurricanes that allows us, for the first time, to calculate the correlation of damage with integrated power dissipation and integrated kinetic energy of all hurricanes at landfall since 1988. We find that those metrics, which include the horizontal wind structure, rather than just maximum intensity, are much better correlated with the hurricane cost. The vertical wind shear over the main development region of hurricanes plays a more dominant role than the sea surface temperature in controlling these metrics and therefore also ultimately the cost of hurricanes.

  20. Mercury's interior structure constrained by geodesy and present-day thermal state

    Science.gov (United States)

    Rivoldini, Attilio; Van Hoolst, Tim; Beuthe, Mikael; Deproost, Marie-Hélène

    2016-10-01

    Recent measurements of Mercury's spin state and gravitational field strongly constrain Mercury's core radius and core density, but provide little information on the size of its inner core. Both a fully molten liquid core and a core differentiated into a large solid inner core and a liquid outer part are consistent with the observations, although the observed tides seem to exclude an extremely large inner core. The observed global magnetic field could be generated even without a growing inner core, since remelting of iron snow inside the core might produce a sufficiently large buoyancy flux to drive magnetic field generation by compositional convection.Further constraints on Mercury's internal structure can be obtained by studying its thermal state. The inner core radius depends mainly on the thermal state and on the light elements present in the core. Secular cooling and subsequent formation of an inner core lead to the global contraction of the planet, estimated to be about 7 km.In this study we combine geodesy data (88 day libration amplitude, polar moment of inertia, and tidal Love number) with the recent estimate of the radial contraction of Mercury and thermal evolution calculations in order to constrain its interior structure and in particular its inner core. We consider bulk compositions that are in agreement with the reducing formation conditions suggested by remote sensing data of Mercury's surface.

  1. Extracting hurricane eye morphology from spaceborne SAR images using morphological analysis

    Science.gov (United States)

    Lee, Isabella K.; Shamsoddini, Ali; Li, Xiaofeng; Trinder, John C.; Li, Zeyu

    2016-07-01

    Hurricanes are among the most destructive global natural disasters. Thus recognizing and extracting their morphology is important for understanding their dynamics. Conventional optical sensors, due to cloud cover associated with hurricanes, cannot reveal the intense air-sea interaction occurring at the sea surface. In contrast, the unique capabilities of spaceborne synthetic aperture radar (SAR) data for cloud penetration, and its backscattering signal characteristics enable the extraction of the sea surface roughness. Therefore, SAR images enable the measurement of the size and shape of hurricane eyes, which reveal their evolution and strength. In this study, using six SAR hurricane images, we have developed a mathematical morphology method for automatically extracting the hurricane eyes from C-band SAR data. Skeleton pruning based on discrete skeleton evolution (DSE) was used to ensure global and local preservation of the hurricane eye shape. This distance weighted algorithm applied in a hierarchical structure for extraction of the edges of the hurricane eyes, can effectively avoid segmentation errors by reducing redundant skeletons attributed to speckle noise along the edges of the hurricane eye. As a consequence, the skeleton pruning has been accomplished without deficiencies in the key hurricane eye skeletons. A morphology-based analyses of the subsequent reconstructions of the hurricane eyes shows a high degree of agreement with the hurricane eye areas derived from reference data based on NOAA manual work.

  2. Hurricane Ike: Field Investigation Survey (Invited)

    Science.gov (United States)

    Ewing, L.

    2009-12-01

    Hurricane Ike made landfall at 2:10 a.m. on September 13, 2008, as a Category 2 hurricane. The eye of the hurricane crossed over the eastern end of Galveston Island and a large region of the Texas and Louisiana coast experienced extreme winds, waves and water levels, resulting in large impacts from overtopping, overwash, wind and wave forces and flooding. Major damage stretched from Freeport to the southwest and to Port Arthur to the northeast. The effects of the hurricane force winds were felt well inland in Texas and Louisiana and the storm continued to the interior of the US, causing more damage and loss of life. Through the support of the Coasts, Oceans, Ports and Rivers Institute (COPRI) of the American Society of Civil Engineers (ASCE) a team of 14 coastal scientists and engineers inspected the upper Texas coast in early October 2008. The COPRI team surveyed Hurricane Ike’s effects on coastal landforms, structures, marinas, shore protection systems, and other infrastructure. Damages ranges from very minor to complete destruction, depending upon location and elevation. Bolivar Peninsula, to the right of the hurricane path, experienced severe damage and three peninsula communities were completely destroyed. Significant flood and wave damage also was observed in Galveston Island and Brazoria County that were both on the left side of the hurricane path. Beach erosion and prominent overwash fans were observed throughout much of the field investigation area. The post-storm damage survey served to confirm expected performance under extreme conditions, as well as to evaluate recent development trends and conditions unique to each storm. Hurricane Ike confirmed many previously reported observations. One of the main conclusions from the inspection of buildings was that elevation was a key determinant for survival. Elevation is also a major factor in the stability and effectiveness of shore protection. The Galveston Seawall was high enough to provide protection from

  3. Lipopolysaccharide (LPS) inner-core phosphates are required for complete LPS synthesis and transport to the outer membrane in Pseudomonas aeruginosa PAO1.

    Science.gov (United States)

    Delucia, Angela M; Six, David A; Caughlan, Ruth E; Gee, Patricia; Hunt, Ian; Lam, Joseph S; Dean, Charles R

    2011-01-01

    Gram-negative outer membrane (OM) integrity is maintained in part by Mg(2+) cross-links between phosphates on lipid A and on core sugars of adjacent lipopolysaccharide (LPS) molecules. In contrast to other Gram-negative bacteria, waaP, encoding an inner-core kinase, could not be inactivated in Pseudomonas aeruginosa. To examine this further, expression of the kinases WaaP or WapP/WapQ/PA5006 was placed under the control of the arabinose-regulated pBAD promoter. Growth of these strains was arabinose dependent, confirming that core phosphorylation is essential in P. aeruginosa. Transmission electron micrographs of kinase-depleted cells revealed marked invaginations of the inner membrane. SDS-PAGE of total LPS from WaaP-depleted cells showed accumulation of a fast-migrating band. Mass spectrometry (MS) analysis revealed that LPS from these cells exhibits a unique truncated core consisting of two 3-deoxy-d-manno-octulosonic acids (Kdo), two l-glycero-d-manno-heptoses (Hep), and one hexose but completely devoid of phosphates, indicating that phosphorylation by WaaP is necessary for subsequent core phosphorylations. MS analysis of lipid A from WaaP-depleted cells revealed extensive 4-amino-4-deoxy-l-arabinose modification. OM prepared from these cells by Sarkosyl extraction of total membranes or by sucrose density gradient centrifugation lacked truncated LPS. Instead, truncated LPS was detected in the inner membrane fractions, consistent with impaired transport/assembly of this species into the OM. IMPORTANCE Gram-negative bacteria have an outer membrane (OM) comprised of a phospholipid inner leaflet and a lipopolysaccharide (LPS) outer leaflet. The OM protects cells from toxic molecules and is important for survival during infection. The LPS core kinase gene waaP can be deleted in several Gram-negative bacteria but not in Pseudomonas aeruginosa. We used a controlled-expression system to deplete WaaP directly in P. aeruginosa cells, which halted growth. WaaP depletion

  4. Hurricane Rita Poster (September 22, 2005)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Hurricane Rita poster. Multi-spectral image from NOAA-16 shows Hurricane Rita as a category-4 hurricane in the Gulf of Mexico on September 22, 2005. Poster size is...

  5. Hurricane Katrina Poster (August 28, 2005)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Hurricane Katrina poster. Multi-spectral image from NOAA-18 shows a very large Hurricane Katrina as a category 5 hurricane in the Gulf of Mexico on August 28, 2005....

  6. Case study on visualizing hurricanes using illustration-inspired techniques.

    Science.gov (United States)

    Joshi, Alark; Caban, Jesus; Rheingans, Penny; Sparling, Lynn

    2009-01-01

    The devastating power of hurricanes was evident during the 2005 hurricane season, the most active season on record. This has prompted increased efforts by researchers to understand the physical processes that underlie the genesis, intensification, and tracks of hurricanes. This research aims at facilitating an improved understanding into the structure of hurricanes with the aid of visualization techniques. Our approach was developed by a mixed team of visualization and domain experts. To better understand these systems, and to explore their representation in NWP models, we use a variety of illustration-inspired techniques to visualize their structure and time evolution. Illustration-inspired techniques aid in the identification of the amount of vertical wind shear in a hurricane, which can help meteorologists predict dissipation. Illustration-style visualization, in combination with standard visualization techniques, helped explore the vortex rollup phenomena and the mesovortices contained within. We evaluated the effectiveness of our visualization with the help of six hurricane experts. The expert evaluation showed that the illustration-inspired techniques were preferred over existing tools. Visualization of the evolution of structural features is a prelude to a deeper visual analysis of the underlying dynamics.

  7. Impacts of Hurricane Katrina on floodplain forests of the Pearl River: Chapter 6A in Science and the storms-the USGS response to the hurricanes of 2005

    Science.gov (United States)

    Faulkner, Stephen; Barrow, Wylie; Couvillion, Brady R.; Conner, William; Randall, Lori; Baldwin, Michael

    2007-01-01

    Floodplain forests are an important habitat for Neotropical migratory birds. Hurricane Katrina passed through the Pearl River flood plain shortly after making landfall. Field measurements on historical plots and remotely sensed data were used to assess the impact of Hurricane Katrina on the structure of floodplain forests of the Pearl River.

  8. How Hurricanes Get Their Names

    Institute of Scientific and Technical Information of China (English)

    张梅荐

    2000-01-01

    The first people who gave names to hurricanes were those who knew them best the people of Puerto Rico. The small island of Puerto Rico is in the West Indies, off the coast of Florida. This is where all the hurricanes begin that strike the east coast of the United States.

  9. 76 FR 63541 - Design-Basis Hurricane and Hurricane Missiles for Nuclear Power Plants

    Science.gov (United States)

    2011-10-13

    ...-2010-0288] Design-Basis Hurricane and Hurricane Missiles for Nuclear Power Plants AGENCY: Nuclear... Hurricane Missiles for Nuclear Power Plants.'' This regulatory guide provides licensees and applicants with... hurricane and design-basis hurricane-generated missiles that a nuclear power plant should be designed...

  10. Simulations of Hurricane Nadine (2012) during HS3 Using the NASA Unified WRF with Aerosol-Cloud Microphysics-Radiation Coupling

    Science.gov (United States)

    Shi, J. J.; Braun, S. A.; Sippel, J. A.; Tao, W. K.; Tao, Z.

    2014-12-01

    The impact of the SAL on the development and intensification of hurricanes has garnered significant attention in recent years. Many past studies have shown that synoptic outbreaks of Saharan dust, which usually occur from late spring to early fall and can extend from western Africa across the Atlantic Ocean into the Caribbean, can have impacts on hurricane genesis and subsequent intensity change. The Hurricane and Severe Storm Sentinel (HS3) mission is a multiyear NASA field campaign with the goal of improving understanding of hurricane formation and intensity change. One of HS3's primary science goals is to obtain measurements to help determine the extent to which the Saharan air layer impacts storm intensification. HS3 uses two of NASA's unmanned Global Hawk aircrafts equipped with three instruments each to measure characteristics of the storm environment and inner core. The Goddard microphysics and longwave/shortwave schemes in the NASA Unified Weather Research and Forecasting (NU-WRF) model have been coupled in real-time with the Goddard Chemistry Aerosol Radiation and Transport (GOCART) model in WRF-Chem to account for the direct (radiation) and indirect (microphysics) impact. NU-WRF with interactive aerosol-cloud-radiation physics is used to generate 30-member ensemble simulations of Nadine (2012) with and without the aerosol interactions. Preliminary conclusions related to the impact of the SAL on the evolution of Nadine from the HS3 observations and model output will be described.

  11. A Look Inside Hurricane Alma

    Science.gov (United States)

    2002-01-01

    Hurricane season in the eastern Pacific started off with a whimper late last month as Alma, a Category 2 hurricane, slowly made its way up the coast of Baja California, packing sustained winds of 110 miles per hour and gusts of 135 miles per hour. The above image of the hurricane was acquired on May 29, 2002, and displays the rainfall rates occurring within the storm. Click the image above to see an animated data visualization (3.8 MB) of the interior of Hurricane Alma. The images of the clouds seen at the beginning of the movie were retrieved from the National Oceanic and Atmospheric Association's (NOAA's) Geostationary Orbiting Environmental Satellite (GOES) network. As the movie continues, the clouds are peeled away to reveal an image of rainfall levels in the hurricane. The rainfall data were obtained by the Precipitation Radar aboard NASA's Tropical Rainfall Measuring Mission (TRMM) satellite. The Precipitation Radar bounces radio waves off of clouds to retrieve a reading of the number of large, rain-sized droplets within the clouds. Using these data, scientists can tell how much precipitation is occurring within and beneath a hurricane. In the movie, yellow denotes areas where 0.5 inches of rain is falling per hour, green denotes 1 inch per hour, and red denotes over 2 inches per hour. (Please note that high resolution still images of Hurricane Alma are available in the NASA Visible Earth in TIFF format.) Image and animation courtesy Lori Perkins, NASA Goddard Space Flight Center Scientific Visualization Studio

  12. Potential of MODIS EVI in Identifying Hurricane Disturbance to Coastal Vegetation in the Northern Gulf of Mexico

    Directory of Open Access Journals (Sweden)

    Fugui Wang

    2009-12-01

    Full Text Available Frequent hurricane landfalls along the northern Gulf of Mexico, in addition to causing immediate damage to vegetation, also have long term effects on coastal ecosystem structure and function. This study investigated the utility of using time series enhanced vegetation index (EVI imagery composited in MODIS product MOD13Q1 for assessing hurricane damage to vegetation and its recovery. Vegetation in four US coastal states disturbed by five hurricanes between 2002 and 2008 were explored by change imagery derived from pre- and post-hurricane EVI data. Interpretation of the EVI changes within months and between years distinguished a clear disturbance pattern caused by Hurricanes Katrina and Rita in 2005, and a recovering trend of the vegetation between 2005 and 2008, particularly within the 100 km coastal zone. However, for Hurricanes Gustav, Ike, and Lili, the disturbance pattern which varied by the change imagery were not noticeable in some images due to lighter vegetation damage. The EVI pre- and post-hurricane differences between two adjacent years and around one month after hurricane disturbance provided the most likely damage area and patterns. The study also revealed that as hurricanes damaged vegetation in some coastal areas, strong precipitation associated with these storms may benefit growth of vegetation in other areas. Overall, the study illustrated that the MODIS product could be employed to detect severe hurricane damage to vegetation, monitor vegetation recovery dynamics, and assess benefits of hurricanes to vegetation.

  13. Hurricane recovery at Cabezas de San Juan, Puerto Rico, and research opportunities at Conservation Trust Reserves

    Science.gov (United States)

    Peter L. Weaver; Elizabeth Padilla Rodriguez

    2009-01-01

    The Cabezas de San Juan Natural Reserve (El Faro), an exposed peninsular area located in the Subtropical dry forest of northeastern Puerto Rico, was impacted by hurricanes Hugo (1989) and Georges (1998). From 1998 to 2008, a 0.10 ha plot was used to assess forest structure, species composition, and stem growth. During post-hurricane recovery, stem density, tree height...

  14. 33 CFR 203.49 - Rehabilitation of Hurricane and Shore Protection Projects.

    Science.gov (United States)

    2010-07-01

    ... Shore Protection Projects. 203.49 Section 203.49 Navigation and Navigable Waters CORPS OF ENGINEERS... authorized hurricane or shore protection structure damaged or destroyed by wind, wave, or water action of an... of damage to a Hurricane/Shore Protection Project. “Prolongation or severity” means a Category 3...

  15. The Dynamical Characteristics and Wave Structure of Typhoon Rananim (2004)

    Institute of Scientific and Technical Information of China (English)

    MING Jie; NI Yunqi; SHEN Xinyong

    2009-01-01

    Typhoon Rananim (2004) was one of the severest typhoons landfalling the Chinese mainland from 1996 to 2004. It brought serious damage and induced prodigious economical loss. Using a new generation of mesoscale model, named the Weather Research and Forecasting (WRF) modeling system, with 1.667 km grid horizontal spacing on the finest nested mesh, Rananim was successfully simulated in terms of track, intensity, eye, eyewall, and spiral rainbands. We compared the structures of Rananim to those of hurricanes in previous studies and observations to assess the validity of simulation. The three-dimensional (3D) dynamic and thermal structures of eye and eyewall were studied based on the simulated results. The focus was investigation of the characteristics of the vortex Rossby waves in the inner-core region. We found that the Rossby vortex waves propagate azimuthally upwind against the azimuthal mean tangential flow around the eyewall, and their period was longer than that of an air parcel moving within the azimuthal mean tangential flow. They also propagated outward against the boundary layer inflow of the azimuthal mean vortex. Futhermore, we studied the connection between the spiral potential vorticity (PV) bands and spiral rainbands, and found that the vortex Rossby waves played an important role in the formation process of spiral rainbands.

  16. Household Adjustments to Hurricane Katrina

    National Research Council Canada - National Science Library

    Meri Davlasheridze; Qin Fan

    2017-01-01

    This paper examines household adjustments to Hurricane Katrina by estimating the effects of Katrina-induced damages on changes in household demographics and income distributions in the Orleans Parish...

  17. Climate change: Unattributed hurricane damage

    Science.gov (United States)

    Hallegatte, Stéphane

    2015-11-01

    In the United States, hurricanes have been causing more and more economic damage. A reanalysis of the disaster database using a statistical method that accounts for improvements in resilience opens the possibility that climate change has played a role.

  18. Monitoring Hurricane Effects on Aquifer Salinity Using ALSM

    Science.gov (United States)

    Sedighi, A.; Starek, M. J.

    2005-12-01

    During the Atlantic hurricane season of 2004, the Florida Pan Handle, Gulf Coast region, was impacted directly by three major hurricanes within approximately a one-month time period. The short temporal span between impacts coupled with the severity of the storms resulted in drastic changes to the littoral zone geomorphology including extensive shoreline erosion and accretion that directly affected the subsurface hydrogeologic environment. The most important direct physical effects of a hurricane are the following: coastal erosion, shoreline inundation owing to higher than normal tide levels plus increased temporary surge levels during storms, and saltwater intrusion primarily into estuaries and groundwater aquifers. Erosion and deposition during the hurricane change the elevation, which causes change in the position of shoreline. The purpose of this study was to investigate the effects of sea level inundation due to the hurricanes on the near shore subsurface freshwater-saltwater interface. By utilizing high-resolution Airborne Laser Swath Mapping (ALSM) altimetry data acquired shortly before and after the three major hurricane landfalls, the change in shoreline topography was estimated to determine both small-scale and large-scale horizontal encroachment and volumetric change in shoreline. This information was used to develop a before and after variable density groundwater flow model to determine the impact of the hurricanes on the subsurface saltwater-freshwater interface. SEAWAT (Langevin 2001; Guo and Langevin 2002), which simulates three-dimensional, variable-density groundwater flow following a modular structure similar to MODFLOW (McDonald and Harbaugh 1988), was selected to represent the saltwater-freshwater interface in this investigation.

  19. Hurricane Data Analysis Tool

    Science.gov (United States)

    Liu, Zhong; Ostrenga, Dana; Leptoukh, Gregory

    2011-01-01

    In order to facilitate Earth science data access, the NASA Goddard Earth Sciences Data Information Services Center (GES DISC) has developed a web prototype, the Hurricane Data Analysis Tool (HDAT; URL: http://disc.gsfc.nasa.gov/HDAT), to allow users to conduct online visualization and analysis of several remote sensing and model datasets for educational activities and studies of tropical cyclones and other weather phenomena. With a web browser and few mouse clicks, users can have a full access to terabytes of data and generate 2-D or time-series plots and animation without downloading any software and data. HDAT includes data from the NASA Tropical Rainfall Measuring Mission (TRMM), the NASA Quick Scatterometer(QuikSCAT) and NECP Reanalysis, and the NCEP/CPC half-hourly, 4-km Global (60 N - 60 S) IR Dataset. The GES DISC archives TRMM data. The daily global rainfall product derived from the 3-hourly multi-satellite precipitation product (3B42 V6) is available in HDAT. The TRMM Microwave Imager (TMI) sea surface temperature from the Remote Sensing Systems is in HDAT as well. The NASA QuikSCAT ocean surface wind and the NCEP Reanalysis provide ocean surface and atmospheric conditions, respectively. The global merged IR product, also known as, the NCEP/CPC half-hourly, 4-km Global (60 N -60 S) IR Dataset, is one of TRMM ancillary datasets. They are globally-merged pixel-resolution IR brightness temperature data (equivalent blackbody temperatures), merged from all available geostationary satellites (GOES-8/10, METEOSAT-7/5 & GMS). The GES DISC has collected over 10 years of the data beginning from February of 2000. This high temporal resolution (every 30 minutes) dataset not only provides additional background information to TRMM and other satellite missions, but also allows observing a wide range of meteorological phenomena from space, such as, hurricanes, typhoons, tropical cyclones, mesoscale convection system, etc. Basic functions include selection of area of

  20. Hurricane Loss Analysis Based on the Population-Weighted Index

    Directory of Open Access Journals (Sweden)

    Grzegorz Kakareko

    2017-08-01

    Full Text Available This paper discusses different measures for quantifying regional hurricane loss. The main measures used in the past are normalized percentage loss and dollar value loss. In this research, we show that these measures are useful but may not properly reflect the size of the population influenced by hurricanes. A new loss measure is proposed that reflects the hurricane impact on people occupying the structure. For demonstrating the differences among these metrics, regional loss analysis was conducted for Florida. The regional analysis was composed of three modules: the hazard module stochastically modeled the wind occurrence in the region; the vulnerability module utilized vulnerability functions developed in this research to calculate the loss; and the financial module quantified the hurricane loss. In the financial module, we calculated three loss metrics for certain region. The first metric is the average annual loss (AAL which represents the expected loss per year in percentage. The second is the average annual dollar loss which represents the expected dollar amount loss per year. The third is the average annual population-weighted loss (AAPL—a new measure proposed in this research. Compared with the AAL, the AAPL reflects the number of people influenced by the hurricane. The advantages of the AAPL are illustrated using three different analysis examples: (1 conventional regional loss analysis, (2 mitigation potential analysis, and (3 forecasted future loss analysis due to the change in population.

  1. Ocean Surface Wind Speed of Hurricane Helene Observed by SAR

    DEFF Research Database (Denmark)

    Xu, Qing; Cheng, Yongcun; Li, Xiaofeng

    2011-01-01

    The hurricanes can be detected by many remote sensors, but synthetic aperture radar (SAR) can yield high-resolution (sub-kilometer) and low-level wind information that cannot be seen below the cloud by other sensors. In this paper, an assessment of SAR capability of monitoring high-resolution hur......The hurricanes can be detected by many remote sensors, but synthetic aperture radar (SAR) can yield high-resolution (sub-kilometer) and low-level wind information that cannot be seen below the cloud by other sensors. In this paper, an assessment of SAR capability of monitoring high......-resolution hurricane was conducted. A case study was carried out to retrieve ocean surface wind field from C-band RADARSAT-1 SAR image which captured the structure of hurricane Helene over the Atlantic Ocean on 20 September, 2006. With wind direction from the outputs of U.S. Navy Operational Global Atmospheric...... CIWRAP models have been tested to extract wind speed from SAR data. The SAR retrieved ocean surface winds were compared to the aircraft wind speed observations from stepped frequency microwave radiometer (SFMR). The results show the capability of hurricane wind monitoring by SAR....

  2. Hurricane Wilma Poster (October 24, 2005)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Hurricane Wilma poster. Multi-spectral image from NOAA-18 shows Hurricane Wilma exiting Florida off the east Florida coast on October 24, 2005. Poster size is 34"x30".

  3. Hurricane Hugo Poster (September 21, 1989)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Hurricane Hugo poster. Multi-spectral image from NOAA-11 captures Hurricane Hugo slamming into South Carolina coast on September 21, 1989. Poster size is 36"x36".

  4. Hurricane Sandy Poster (October 29, 2012)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Hurricane Sandy poster. Multi-spectral image from Suomi-NPP shows Hurricane Sandy approaching the New Jersey Coast on October 29, 2012. Poster size is approximately...

  5. Hurricane Jeanne Poster (September 25, 2004)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Hurricane Jeanne poster. Multi-spectral image from NOAA-16 shows Hurricane Jeanne near Grand Bahama Island on September 25, 2004. Poster size is 34"x30".

  6. Hurricane Charley Poster (August 13, 2004)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Hurricane Charley poster. Multi-spectral image from NOAA-17 shows a small but powerful hurricane heading toward southern Florida on August 13, 2004. Poster dimension...

  7. Hurricane Isabel Poster (September 18, 2003)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Hurricane Isabel poster. Multi-spectral image from NOAA-17 shows Hurricane Isabel making landfall on the North Carolina Outer Banks on September 18, 2003. Poster...

  8. Hurricane Frances Poster (September 5, 2004)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Hurricane Frances poster. Multi-spectral image from NOAA-17 shows Hurricane Frances over central Florida on September 5, 2004. Poster dimension is approximately...

  9. Hurricane Ivan Poster (September 15, 2004)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Hurricane Ivan poster. Multi-spectral image from NOAA-16 shows Hurricane Ivan in the Gulf of Mexico on September 15, 2004. Poster size is 34"x30".

  10. Hurricane disturbance and recovery of energy balance, CO2 fluxes and canopy structure in a mangrove forest of the Florida Everglades

    Science.gov (United States)

    Barr, Jordan G.; Engel, Vic; Smith, Thomas J.; Fuentes, Jose D.

    2012-01-01

    Eddy covariance (EC) estimates of carbon dioxide (CO2) fluxes and energy balance are examined to investigate the functional responses of a mature mangrove forest to a disturbance generated by Hurricane Wilma on October 24, 2005 in the Florida Everglades. At the EC site, high winds from the hurricane caused nearly 100% defoliation in the upper canopy and widespread tree mortality. Soil temperatures down to -50 cm increased, and air temperature lapse rates within the forest canopy switched from statically stable to statically unstable conditions following the disturbance. Unstable conditions allowed more efficient transport of water vapor and CO2 from the surface up to the upper canopy layer. Significant increases in latent heat fluxes (LE) and nighttime net ecosystem exchange (NEE) were also observed and sensible heat fluxes (H) as a proportion of net radiation decreased significantly in response to the disturbance. Many of these impacts persisted through much of the study period through 2009. However, local albedo and MODIS (Moderate Resolution Imaging Spectro-radiometer) data (the Enhanced Vegetation Index) indicated a substantial proportion of active leaf area recovered before the EC measurements began 1 year after the storm. Observed changes in the vertical distribution and the degree of clumping in newly emerged leaves may have affected the energy balance. Direct comparisons of daytime NEE values from before the storm and after our measurements resumed did not show substantial or consistent differences that could be attributed to the disturbance. Regression analyses on seasonal time scales were required to differentiate the storm's impact on monthly average daytime NEE from the changes caused by interannual variability in other environmental drivers. The effects of the storm were apparent on annual time scales, and CO2 uptake remained approximately 250 g C m-2 yr-1 lower in 2009 compared to the average annual values measured in 2004–2005. Dry season CO2

  11. Mangroves, hurricanes, and lightning strikes: Assessment of Hurricane Andrew suggests an interaction across two differing scales of disturbance

    Science.gov (United States)

    Smith, Thomas J.; Robblee, Michael B.; Wanless, Harold R.; Doyle, Thomas W.

    1994-01-01

    The track of Hurricane Andrew carried it across one of the most extensive mangrove for ests in the New World. Although it is well known that hurricanes affect mangrove forests, surprisingly little quantitative information exists concerning hurricane impact on forest structure, succession, species composition, and dynamics of mangrove-dependent fauna or on rates of eco-system recovery (see Craighead and Gilbert 1962, Roth 1992, Smith 1992, Smith and Duke 1987, Stoddart 1969).After Hurricane Andrew's passage across south Florida, we assessed the environmental damage to the natural resources of the Everglades and Biscayne National Parks. Quantitative data collected during subsequent field trips (October 1992 to July 1993) are also provided. We present measurements of initial tree mortality by species and size class, estimates of delayed (or continuing) tree mortality, and observations of geomorphological changes along the coast and in the forests that could influence the course of forest recovery. We discuss a potential interaction across two differing scales of disturbance within mangrove forest systems: hurricanes and lightning strikes.

  12. Forecasting Hurricane by Satellite Image

    Science.gov (United States)

    Liu, M. Y.

    Earth is an endanger planet. Severe weather, especially hurricanes, results in great disaster all the world. World Meteorology Organization and United Nations Environment Program established intergovernment Panel on Climate Change (IPCC) to offer warnings about the present and future disasters of the Earth. It is the mission for scientists to design warning system to predict the severe weather system and to reduce the damage of the Earth. Hurricanes invade all the world every year and made millions damage to all the people. Scientists in weather service applied satellite images and synoptic data to forecast the information for the next hours for warning purposes. Regularly, hurricane hits on Taiwan island directly will pass through her domain and neighbor within 10 hours. In this study, we are going to demonstrate a tricky hurricane NARI invaded Taiwan on September 16, 2000. She wandered in the neighborhood of the island more than 72 hours and brought heavy rainfall over the island. Her track is so tricky that scientists can not forecast her path using the regular method. Fortunately, all scientists in the Central Weather Bureau paid their best effort to fight against the tricky hurricane. Applying the new developed technique to analysis the satellite images with synoptic data and radar echo, scientists forecasted the track, intensity and rainfall excellently. Thus the damage of the severe weather reduced significantly.

  13. Atlantic hurricane response to geoengineering

    Science.gov (United States)

    Moore, John; Grinsted, Aslak; Ji, Duoying; Yu, Xiaoyong; Guo, Xiaoran

    2015-04-01

    Devastating Atlantic hurricanes are relatively rare events. However their intensity and frequency in a warming world may rapidly increase - perhaps by a factor of 5 for a 2°C mean global warming. Geoengineering by sulphate aerosol injection preferentially 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 6 Earth System Model simulations of climate under the GeoMIP G3 and G4 schemes that use aerosols to reduce the radiative forcing under the RCP4.5 scenario. We find that although temperatures are ameliorated by geoengineering, the numbers of storm surge events as big as that caused the 2005 Katrina hurricane are only slightly reduced compared with no geoengineering. As higher levels of sulphate aerosol injection produce diminishing returns in terms of cooling, but cause undesirable effects in various regions, it seems that stratospheric aerosol geoengineering is not an effective method of controlling hurricane damage.

  14. The observed analysis on the wave spectra of Hurricane Juan (2003)

    Institute of Scientific and Technical Information of China (English)

    XU Fumin; BUI THI Thuy Duyen; PERRIE Will

    2014-01-01

    Hurricane Juan provides an excellent opportunity to probe into the detailed wave spectral patterns and spectral parameters of a hurricane system, with enough wave spectral observations around Juan’s track in the deep ocean and shallow coastal water. In this study, Hurricane Juan and wave observation stations around Juan’s track are introduced. Variations of wave composition are discussed and analyzed based on time series of one-dimensional frequency spectra, as well as wave steepness around Juan’s track:before, dur-ing, and after Juan’s passing. Wave spectral involvement is studied based on the observed one-dimensional spectra and two-dimensional spectra during the hurricane. The standardization method of the observed wave spectra during Hurricane Juan is discussed, and the standardized spectra show relatively conservative behavior, in spite of the huge variation in wave spectral energy, spectral peak, and peak frequency during this hurricane. Spectral widths’ variation during Hurricane Juan are calculated and analyzed. A two-layer nesting WW3 model simulation is applied to simulate the one-dimensional and two-dimensional wave spectra, in order to examine WW3’s ability in simulating detailed wave structure during Hurricane Juan.

  15. Year-ahead prediction of US landfalling hurricane numbers: intense hurricanes

    OpenAIRE

    Khare, Shree; Jewson, Stephen

    2005-01-01

    We continue with our program to derive simple practical methods that can be used to predict the number of US landfalling hurricanes a year in advance. We repeat an earlier study, but for a slightly different definition landfalling hurricanes, and for intense hurricanes only. We find that the averaging lengths needed for optimal predictions of numbers of intense hurricanes are longer than those needed for optimal predictions of numbers of hurricanes of all strengths.

  16. 7 CFR 701.50 - 2005 hurricanes.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 7 2010-01-01 2010-01-01 false 2005 hurricanes. 701.50 Section 701.50 Agriculture... ADMINISTERED UNDER THIS PART § 701.50 2005 hurricanes. In addition benefits elsewhere allowed by this part, claims related to calendar year 2005 hurricane losses may be allowed to the extent provided for in §§ 701...

  17. Hurricane Katrina impacts on Mississippi forests

    Science.gov (United States)

    Sonja N. Oswalt; Christopher Oswalt; Jeffery Turner

    2008-01-01

    Hurricane Katrina triggered public interest and concern for forests in Mississippi that required rapid responses from the scientific community. A uniform systematic sample of 3,590 ground plots were established and measured in 687 days immediately after the impact of Hurricane Katrina on the Gulf Coast. The hurricane damaged an estimated 521 million trees with more...

  18. Hurricane Hazel: Canada's storm of the century

    National Research Council Canada - National Science Library

    Gifford, Jim

    2004-01-01

    ... For EleanorHurricane_Hazel_Interior.qxd 6/22/04 3:35 PM Page 3 HURRICANE HAZEL Canada's Storm of the Century Jim Gifford The dundurn Group Toronto * OxfordHurricane_Hazel_Interior.qxd 6/22/04 3:35...

  19. Ocean surface waves in Hurricane Ike (2008) and Superstorm Sandy (2012): Coupled model predictions and observations

    Science.gov (United States)

    Chen, Shuyi S.; Curcic, Milan

    2016-07-01

    Forecasting hurricane impacts of extreme winds and flooding requires accurate prediction of hurricane structure and storm-induced ocean surface waves days in advance. The waves are complex, especially near landfall when the hurricane winds and water depth varies significantly and the surface waves refract, shoal and dissipate. In this study, we examine the spatial structure, magnitude, and directional spectrum of hurricane-induced ocean waves using a high resolution, fully coupled atmosphere-wave-ocean model and observations. The coupled model predictions of ocean surface waves in Hurricane Ike (2008) over the Gulf of Mexico and Superstorm Sandy (2012) in the northeastern Atlantic and coastal region are evaluated with the NDBC buoy and satellite altimeter observations. Although there are characteristics that are general to ocean waves in both hurricanes as documented in previous studies, wave fields in Ike and Sandy possess unique properties due mostly to the distinct wind fields and coastal bathymetry in the two storms. Several processes are found to significantly modulate hurricane surface waves near landfall. First, the phase speed and group velocities decrease as the waves become shorter and steeper in shallow water, effectively increasing surface roughness and wind stress. Second, the bottom-induced refraction acts to turn the waves toward the coast, increasing the misalignment between the wind and waves. Third, as the hurricane translates over land, the left side of the storm center is characterized by offshore winds over very short fetch, which opposes incoming swell. Landfalling hurricanes produce broader wave spectra overall than that of the open ocean. The front-left quadrant is most complex, where the combination of windsea, swell propagating against the wind, increasing wind-wave stress, and interaction with the coastal topography requires a fully coupled model to meet these challenges in hurricane wave and surge prediction.

  20. Socioecological disparities in New Orleans following Hurricane Katrina

    Science.gov (United States)

    Joshua A. Lewis; Wayne C. Zipperer; Henrik Ernstson; Brittany Bernik; Rebecca Hazen; Thomas Elmqvist; Michael J. Blum

    2017-01-01

    Despite growing interest in urban resilience, remarkably little is known about vegetation dynamics in the aftermath of disasters. In this study, we examined the composition and structure of plant communities across New Orleans (Louisiana, USA) following catastrophic flooding triggered by levee failures during Hurricane Katrina in 2005. Focusing on eight...

  1. A Universal Hurricane Frequency Function

    CERN Document Server

    Ehrlich, Robert

    2010-01-01

    Evidence is provided that the global distribution of tropical hurricanes is principally determined by a universal function H of a single variable z that in turn is expressible in terms of the local sea surface temperature and latitude. The data-driven model presented here carries stark implications for the large increased numbers of hurricanes which it predicts for a warmer world. Moreover, the rise in recent decades in the numbers of hurricanes in the Atlantic, but not the Pacific basin, is shown to have a simple explanation in terms of the specific form of H(z), which yields larger percentage increases when a fixed increase in sea surface temperature occurs at higher latitudes and lower temperatures.

  2. Generic Hurricane Extreme Seas State

    DEFF Research Database (Denmark)

    Wehmeyer, Christof; Skourup, Jesper; Frigaard, Peter

    2012-01-01

    Extreme sea states, which the IEC 61400-3 (2008) standard requires for the ultimate limit state (ULS) analysis of offshore wind turbines are derived to establish the design basis for the conceptual layout of deep water floating offshore wind turbine foundations in hurricane affected areas...... data is required for a type specific conceptual design. ULS conditions for different return periods are developed, which can subsequently be applied in siteindependent analysis and conceptual design. Recordings provided by National Oceanic and Atmospheric Administration (NOAA), of hurricanes along...... for hurricane generates seas by Young (1998, 2003, and 2006), requiring maximum wind speeds, forward velocity and radius to maximum wind speed. An averaged radius to maximum sustained wind speeds, according to Hsu et al. (1998) and averaged forward speed of cyclonic storms are applied in the initial state...

  3. The dynamics of hurricane balls

    Science.gov (United States)

    Andersen, W. L.; Werner, Steven

    2015-09-01

    We examine the theory of the hurricane balls toy. This toy consists of two steel balls, welded together that are sent spinning on a horizontal surface somewhat like a top. Unlike a top, at high frequency the symmetry axis approaches a limiting inclination that is not perpendicular to the surface. We calculate (and experimentally verify) the limiting inclinations for three toy geometries. We find that at high frequencies, hurricane balls provide an easily realized and testable example of the Poinsot theory of freely rotating symmetrical bodies.

  4. Hurricane Season: Are You Ready?

    Centers for Disease Control (CDC) Podcasts

    2012-09-24

    Hurricanes are one of Mother Nature’s most powerful forces. Host Bret Atkins talks with CDC’s National Center for Environmental Health Director Dr. Chris Portier about the main threats of a hurricane and how you can prepare.  Created: 9/24/2012 by Office of Public Health Preparedness and Response (OPHPR), National Center for Environmental Health (NCEH), and the Agency for Toxic Substances and Disease Registry (ATSDR).   Date Released: 9/24/2012.

  5. Using a Geographic Information System to Assess the Risk of Hurricane Hazards on the Maya Civilization

    Science.gov (United States)

    Weigel, A. M.; Griffin, R.; Sever, T.

    2014-12-01

    The extent of the Maya civilization spanned across portions of modern day Mexico, Belize, Guatemala, El Salvador and Honduras. Paleoclimatic studies suggest this region has been affected by strong hurricanes for the past six thousand years, reinforced by archeological evidence from Mayan records indicating they experienced strong storms. It is theorized hurricanes aided in the collapse of the Maya, damaging building structures, agriculture, and ceasing industry activities. Today, this region is known for its active tropical climatology, being hit by numerous strong storms including Hurricane Dean, Iris, Keith, and Mitch. This research uses a geographic information system (GIS) to model hurricane hazards, and assess the risk posed on the Maya civilization. GIS has the ability to handle various layer components making it optimal for combining parameters necessary for assessing the risk of experiencing hurricane related hazards. For this analysis, high winds, storm surge flooding, non-storm surge related flooding, and rainfall triggered landslides were selected as the primary hurricane hazards. Data sets used in this analysis include the National Climatic Data Center International Best Track Archive for Climate Stewardships (IBTrACS) hurricane tracks, Shuttle Radar Topography Mission Digital Elevation Model, WorldClim monthly accumulated precipitation, USGS HydroSHEDS river locations, Harmonized World Soil Database soil types, and known Maya site locations from the Electronic Atlas of Ancient Maya Sites. ArcGIS and ENVI software were utilized to process data and model hurricane hazards. To assess locations at risk of experiencing high winds, a model was created using ArcGIS Model Builder to map each storm's temporal wind profile, and adapted to simulate forward storm velocity, and storm frequency. Modeled results were then combined with physical land characteristics, meteorological, and hydrologic data to identify areas likely affected. Certain areas along the eastern

  6. Hurricane interaction with the upper ocean in the Amazon-Orinoco plume region

    Science.gov (United States)

    Androulidakis, Yannis; Kourafalou, Vassiliki; Halliwell, George; Le Hénaff, Matthieu; Kang, Heesook; Mehari, Michael; Atlas, Robert

    2016-12-01

    The evolution of three successive hurricanes (Katia, Maria, and Ophelia) is investigated over the river plume area formed by the Amazon and Orinoco river outflows during September of 2011. The study focuses on hurricane impacts on the ocean structure and the ocean feedback influencing hurricane intensification. High-resolution (1/25° × 1/25° horizontal grid) numerical simulations of the circulation in the extended Atlantic Hurricane Region (Caribbean Sea, Gulf of Mexico, and Northwest Atlantic Ocean) were used to investigate the upper ocean response during the three hurricane-plume interaction cases. The three hurricanes revealed different evolution and intensification characteristics over an area covered by brackish surface waters. The upper ocean response to the hurricane passages over the plume affected region showed high variability due to the interaction of oceanic and atmospheric processes. The existence of a barrier layer (BL), formed by the offshore spreading of brackish waters, probably facilitated intensification of the first storm (Hurricane Katia) because the river-induced BL enhanced the resistance of the upper ocean to cooling. This effect was missing in the subsequent two hurricanes (Maria and Ophelia) as the eroded BL (due to Katia passage) allowed the upper ocean cooling to be increased. As a consequence, the amount of ocean thermal energy provided to these storms was greatly reduced, which acted to limit intensification. Numerical experiments and analyses, in tandem with observational support, lead to the conclusion that the presence of a river plume-induced BL is a strong factor in the ocean conditions influencing hurricane intensification.

  7. Simulation of hurricane response to suppression of warm rain by sub-micron aerosols

    Directory of Open Access Journals (Sweden)

    D. Rosenfeld

    2007-07-01

    Full Text Available The feasibility of hurricane modification was investigated for hurricane Katrina using the Weather Research and Forecasting Model (WRF. The possible impact of seeding of clouds with submicron cloud condensation nuclei (CCN on hurricane structure and intensity as measured by nearly halving of the area covered by hurricane force winds was simulated by "turning–off" warm rain formation in the clouds at Katrina's periphery (where wind speeds were less than 22 m s−1. This simplification of the simulation of aerosol effects is aimed at evaluating the largest possible response. This resulted in the weakening of the hurricane surface winds compared to the "non-seeded" simulated storm during the first 24 h within the entire tropical cyclone (TC area compared to a control simulation without warm rain suppression. Later, the seeding-induced evaporative cooling at the TC periphery led to a shrinking of the eye and hence to some increase in the wind within the small central area of the TC. Yet, the overall strength of the hurricane, as defined by the area covered by hurricane force winds, decreased in response to the suppressed warm rain at the periphery, as measured by a 25% reduction in the radius of hurricane force winds. In a simulation with warm rain suppression throughout the hurricane, the radius of the hurricane force winds was reduced by more than 42%, and although the diameter of the eye shrunk even further the maximum winds weakened. This shows that the main mechanism by which suppressing warm rain weakens the TC is the low level evaporative cooling of the un-precipitated cloud drops and the added cooling due to melting of precipitation that falls from above.

  8. EarthLabs - Investigating Hurricanes: Earth's Meteorological Monsters

    Science.gov (United States)

    McDaris, J. R.; Dahlman, L.; Barstow, D.

    2007-12-01

    which students investigate the different interactions involved in hurricane generation, steering, and intensification. Students analyze a variety of visualization resources looking for patterns in occurrence and to develop an understanding of hurricane structure. They download archived data about past hurricanes and produce temporal and spatial plots to discover patterns in hurricane life cycles. They investigate the relationship between hurricane wind speed and factors such as barometric pressure and sea surface temperature by conducting spreadsheet analyses on archived data. They also conduct hands-on laboratory experiments in order to understand the physical processes that underpin energy transfer in convection, condensation, and latent heat. These activities highlight Earth science as a vital, rich, invigorating course, employing state-of-the-art technologies and in-depth labs with high relevance for our daily lives and the future.

  9. Hurricane Sandy Washover Deposits on Southern Long Beach Island, NJ

    Science.gov (United States)

    Bishop, J. M.; Richmond, B. M.; Kane, H. H.; Lunghino, B.

    2015-12-01

    Hurricane Sandy washover deposits were investigated at Forsyth National Wildlife Refuge (FNWR) on Southern Long Beach Island, New Jersey in order to map deposit thickness and characterize the sedimentary deposits. FNWR was chosen as a field area because there has been relatively little anthropogenic shoreline modification since washover deposition from Hurricane Sandy. Sediment, elevation, and geophysical data were collected during the April 2015 field campaign, approximately two and a half years after the storm. Sediment deposit data included trenches, stratigraphic descriptions, bulk sediment samples, push cores, Russian cores, and photos. Computed tomography (CT) scanning was conducted on push cores in order to acquire high resolution imaging of density, grain size, and sedimentary structure. Profiles of washover elevation were measured using Differential GPS with Real Time Kinematic processing. Ground Penetrating Radar data was collected to image the depth of the deposit and identify sedimentary structures. These data sets are compared to pre- and post -Sandy lidar surveys in order to determine post-Sandy modification in the two and a half years following the hurricane. We compare sediment thickness and sedimentary characteristics to hurricane Sandy deposits elsewhere along the U.S. eastern seaboard and to tsunami deposits.

  10. Hurricane intensification along United States coast suppressed during active hurricane periods.

    Science.gov (United States)

    Kossin, James P

    2017-01-19

    The North Atlantic ocean/atmosphere environment exhibits pronounced interdecadal variability that is known to strongly modulate Atlantic hurricane activity. Variability in sea surface temperature (SST) is correlated with hurricane variability through its relationship with the genesis and thermodynamic potential intensity of hurricanes. Another key factor that governs the genesis and intensity of hurricanes is ambient environmental vertical wind shear (VWS). Warmer SSTs generally correlate with more frequent genesis and greater potential intensity, while VWS inhibits genesis and prevents any hurricanes that do form from reaching their potential intensity. When averaged over the main hurricane-development region in the Atlantic, SST and VWS co-vary inversely, so that the two factors act in concert to either enhance or inhibit basin-wide hurricane activity. Here I show, however, that conditions conducive to greater basin-wide Atlantic hurricane activity occur together with conditions for more probable weakening of hurricanes near the United States coast. Thus, the VWS and SST form a protective barrier along the United States coast during periods of heightened basin-wide hurricane activity. Conversely, during the most-recent period of basin-wide quiescence, hurricanes (and particularly major hurricanes) near the United States coast, although substantially less frequent, exhibited much greater variability in their rate of intensification, and were much more likely to intensify rapidly. Such heightened variability poses greater challenges to operational forecasting and, consequently, greater coastal risk during hurricane events.

  11. Hurricane intensification along United States coast suppressed during active hurricane periods

    Science.gov (United States)

    Kossin, James P.

    2017-01-01

    The North Atlantic ocean/atmosphere environment exhibits pronounced interdecadal variability that is known to strongly modulate Atlantic hurricane activity. Variability in sea surface temperature (SST) is correlated with hurricane variability through its relationship with the genesis and thermodynamic potential intensity of hurricanes. Another key factor that governs the genesis and intensity of hurricanes is ambient environmental vertical wind shear (VWS). Warmer SSTs generally correlate with more frequent genesis and greater potential intensity, while VWS inhibits genesis and prevents any hurricanes that do form from reaching their potential intensity. When averaged over the main hurricane-development region in the Atlantic, SST and VWS co-vary inversely, so that the two factors act in concert to either enhance or inhibit basin-wide hurricane activity. Here I show, however, that conditions conducive to greater basin-wide Atlantic hurricane activity occur together with conditions for more probable weakening of hurricanes near the United States coast. Thus, the VWS and SST form a protective barrier along the United States coast during periods of heightened basin-wide hurricane activity. Conversely, during the most-recent period of basin-wide quiescence, hurricanes (and particularly major hurricanes) near the United States coast, although substantially less frequent, exhibited much greater variability in their rate of intensification, and were much more likely to intensify rapidly. Such heightened variability poses greater challenges to operational forecasting and, consequently, greater coastal risk during hurricane events.

  12. 飓风作用下某大跨体育馆屋盖的结构选型分析%ANALYSES OF STRUCTURAL TYPE SELECTION FOR THE LONG-SPAN ROOF OF A GYMNASIUM CONSIDERING HURRICANE

    Institute of Scientific and Technical Information of China (English)

    李布辉; 张大长; 包涛

    2012-01-01

    Analyses of structural form selection of a gymnasium in the Philippines were carried out. The maximum wind speed for design is 215 km/h, the wind force is 17 level and it belongs to hurricane. Therefore, the designs of long-span roof become especially difficult. The lower natatorium roof was used to be the top roof' s supports and stand. The top roof was a long-span space steel truss structure which had a span dimension of 130. 0 m ×31.0 m. Considering the characteristics such as roof being large span and its overall structure being stiper-long, the plane pipe truss was used in top roof and the spatial triangle pipe truss structure was used in the lower roof and stands. Due to comparison and selection of different structure schemes, pipe truss structure, space truss structure set with pulling up and down prestressed cable, space truss structure with pulling up prestressed cable and self-balance steel-tube filled with concrete were selected. Analyses models were built and the nonlinear analyses were performed. Structural deflection, members dimension, structural materials, and construction difficuhies were investigated, it was found that scheme 3 had a good economy and structural performance, which was suitable for long-span structures under hurricane. The research results can be referel3ced by designing other similar long-span structures.%菲律宾某地最大设计风速达到215 km/h,风力17级,属于飓风,因此大跨屋盖的结构设计异常困难。该地的某大跨体育馆的下层屋盖为游泳馆屋盖,并作为上层屋盖的支承点和看台;上层屋盖为大跨度空间钢桁架结构,屋盖东西长为130.0 m,南北宽为31.0 m。考虑屋盖跨度大、整体结构超长的特点,上层屋盖采用平面管桁架形式,下侧游泳馆屋面及看台采用空间三角管桁架结构。基于屋盖结构方案的可行性比选,选取普通框架管桁架结构、斜拉空间桁架、斜拉空间桁架加配重3种方案,进行结构整体建

  13. 77 FR 64564 - Implementation of Regulatory Guide 1.221 on Design-Basis Hurricane and Hurricane Missiles

    Science.gov (United States)

    2012-10-22

    ... COMMISSION Implementation of Regulatory Guide 1.221 on Design-Basis Hurricane and Hurricane Missiles AGENCY....221 on Design-Basis Hurricane and Hurricane Missiles.'' The purpose of this ISG is to supplement the guidance regarding the application of Regulatory Guide 1.221, ``Design-Basis Hurricane and...

  14. Effects and outcomes of Caribbean hurricanes in a climate change scenario.

    Science.gov (United States)

    Lugo, A E

    2000-11-15

    Hurricanes are complex disturbance systems with significant effects on vegetation and built-up land. This paper summarizes research on the effects and outcomes of hurricanes on Caribbean forests. Twelve effects and outcome topics are presented: sudden and massive tree mortality; delayed patterns of tree mortality; alternative methods of forest regeneration; opportunities for a change in successional direction; high species turnover and opportunities for species change in forests; diversity of age classes; faster biomass and nutrient turnover; species substitutions and changes in turnover time of biomass and nutrients; lower aboveground biomass in mature vegetation; carbon sinks; selective pressure on organisms; and convergence of community structure and organization. Effects of hurricanes on urban systems are also discussed. While there is scientific uncertainty as to whether hurricane frequencies and intensity will change as a result of global climate change, available understanding on the effects and outcomes of hurricanes can be used to anticipate possible effects of either increasing or decreasing hurricane frequency and intensity. Proposed mitigation actions and research priorities can be effective and desirable even if the frequency and intensity of hurricanes remains unchanged.

  15. Hurricane Footprints in Global Climate Models

    Directory of Open Access Journals (Sweden)

    Francisco J. Tapiador

    2008-11-01

    Full Text Available This paper addresses the identification of hurricanes in low-resolution global climate models (GCM. As hurricanes are not fully resolvable at the coarse resolution of the GCMs (typically 2.5 × 2.5 deg, indirect methods such as analyzing the environmental conditions favoring hurricane formation have to be sought. Nonetheless, the dynamical cores of the models have limitations in simulating hurricane formation, which is a far from fully understood process. Here, it is shown that variations in the specific entropy rather than in dynamical variables can be used as a proxy of the hurricane intensity as estimated by the Accumulated Cyclone Energy (ACE. The main application of this research is to ascertain the changes in the hurricane frequency and intensity in future climates.

  16. The great Louisiana hurricane of August 1812

    OpenAIRE

    Mock, Cary J.; Chenoweth, Michael; Altamirano, Isabel; Rodgers, Matthew D.; García Herrera, Ricardo

    2010-01-01

    Major hurricanes are prominent meteorological hazards of the U.S. Atlantic and Gulf coasts. However, the official modern record of Atlantic basin tropical cyclones starts at 1851, and it does not provide a comprehensive measure of the frequency and magnitude of major hurricanes. Vast amounts of documentary weather data extend back several centuries, but many of these have not yet been fully utilized for hurricane reconstruction. These sources include weather diaries, ship logbooks, ship prote...

  17. Dynamics and Predictability of Hurricane Dolly (2008)

    Science.gov (United States)

    Fang, J.; Zhang, F.; Weng, Y.

    2008-12-01

    Through several cloud-resolving simulations with the Weather Research and Forecast (WRF-ARW) model, this study examines the dynamics and predictability of Hurricane Dolly (2008) with an emphasis on its initial development (around the time being declared as a tropical storm) and subsequent rapid intensification entering into the Gulf of Mexico. These WRF simulations include three that are directly initialized with the operational NCEP GFS analyses at 06, 12 and 18Z 20 July 2008, respectively (EXP06, EXP12, EXP18) and another the same as EXP06 except that the airborne Doppler velocity observations by a NOAA P3 aircraft during 12-15Z are assimilated with an ensemble-Kalman filter (ENKF06). Among the four experiments, only EXP06 fails to capture the rapid intensification and fails to develop the tropical storm into a mature hurricane. Preliminary comparison between the simulated fields of EXP06 and the GFS analysis at 12Z (e.g., IC of EXP12) indicates that large scale features favorable to the tropical cyclogenesis cannot be properly simulated in EXP06. The initial disturbance is rather weak positioned too far south-west that is far away from the primary convective. However, after the airborne radar data during 12-15Z are assimilated into the model, (from EXP06 into ENKF06), the ENKF06 simulation is greatly improved in that a well-organized warm-core vortex appears at the low level right after radar assimilation, which subsequently developed into a hurricane consistent with timing, track and intensity of observations. Interestingly, there are significant differences in the initial vortex position, structure and evolution among the three simulations (EXP12, EXP18, ENKF06) that all eventually develop a mature hurricane along the observed track (before landfall) with right timing after enters into the Gulf of Mexico. At 18Z 20 July, there is no apparent initial low-level cyclonic vortex in EXP12 and EXP18 (that is assimilated into ENKF06 due to radar observations

  18. Hurricane Excitation of Earth Eigenmodes

    OpenAIRE

    Peters, Randall D.

    2005-01-01

    A non-conventional vertical seismometer, with good low-frequency sensitivity, was used to study earth motions in Macon, Georgia USA during the time of hurricane Charley, August 2004. During its transitions between water and land, the powerful storm showed an interesting history of microseisms and also generated more than half-a-dozen surprisingly coherent oscillations, whose frequencies ranged from 0.9 to 3 mHz.

  19. Hurricane Boundary-Layer Theory

    Science.gov (United States)

    2010-01-01

    2501. Kundu PK. 1990. Fluid Mechanics . Academic Press: San Diego, USA. Kuo HL. 1982. Vortex boundary layer under quadratic surface stress. Boundary...identification of two mechanisms for the spin-up of the mean tangential circulation of a hurricane. The first involves convergence of absolute angular...momentum above the boundary layer, where this quantity is approximately conserved. This mechanism acts to spin up the outer circulation at radii

  20. Lessons Learnt From Hurricane Katrina.

    Science.gov (United States)

    Akundi, Murty

    2008-03-01

    Hurricane Katrina devastated New Orleans and its suburbs on Monday August 29^th, 2005. The previous Friday morning, August 26, the National Hurricane Center indicated that Katrina was a Category One Hurricane, which was expected to hit Florida. By Friday afternoon, it had changed its course, and neither the city nor Xavier University was prepared for this unexpected turn in the hurricane's path. The university had 6 to 7 ft of water in every building and Xavier was closed for four months. Students and university personnel that were unable to evacuate were trapped on campus and transportation out of the city became a logistical nightmare. Email and all electronic systems were unavailable for at least a month, and all cell phones with a 504 area code stopped working. For the Department, the most immediate problem was locating faculty and students. Xavier created a list of faculty and their new email addresses and began coordinating with faculty. Xavier created a web page with advice for students, and the chair of the department created a separate blog with contact information for students. The early lack of a clear method of communication made worse the confusion and dismay among the faculty on such issues as when the university would reopen, whether the faculty would be retained, whether they should seek temporary (or permanent) employment elsewhere, etc. With the vision and determination of President Dr. Francis, Xavier was able to reopen the university in January and ran a full academic year from January through August. Since Katrina, the university has asked every department and unit to prepare emergency preparedness plans. Each department has been asked to collect e-mail addresses (non-Xavier), cell phone numbers and out of town contact information. The University also established an emergency website to communicate. All faculty have been asked to prepare to teach classes electronically via Black board or the web. Questions remain about the longer term issues of

  1. Dynamic Hurricane Data Analysis Tool

    Science.gov (United States)

    Knosp, Brian W.; Li, Peggy; Vu, Quoc A.

    2009-01-01

    A dynamic hurricane data analysis tool allows users of the JPL Tropical Cyclone Information System (TCIS) to analyze data over a Web medium. The TCIS software is described in the previous article, Tropical Cyclone Information System (TCIS) (NPO-45748). This tool interfaces with the TCIS database to pull in data from several different atmospheric and oceanic data sets, both observed by instruments. Users can use this information to generate histograms, maps, and profile plots for specific storms. The tool also displays statistical values for the user-selected parameter for the mean, standard deviation, median, minimum, and maximum values. There is little wait time, allowing for fast data plots over date and spatial ranges. Users may also zoom-in for a closer look at a particular spatial range. This is version 1 of the software. Researchers will use the data and tools on the TCIS to understand hurricane processes, improve hurricane forecast models and identify what types of measurements the next generation of instruments will need to collect.

  2. Shifts in biomass and productivity for a subtropical dry forest in response to simulated elevated hurricane disturbances

    Science.gov (United States)

    Holm, Jennifer A.; Van Bloem, Skip J.; Larocque, Guy R.; Shugart, Herman H.

    2017-02-01

    Caribbean tropical forests are subject to hurricane disturbances of great variability. In addition to natural storm incongruity, climate change can alter storm formation, duration, frequency, and intensity. This model-based investigation assessed the impacts of multiple storms of different intensities and occurrence frequencies on the long-term dynamics of subtropical dry forests in Puerto Rico. Using the previously validated individual-based gap model ZELIG-TROP, we developed a new hurricane damage routine and parameterized it with site- and species-specific hurricane effects. A baseline case with the reconstructed historical hurricane regime represented the control condition. Ten treatment cases, reflecting plausible shifts in hurricane regimes, manipulated both hurricane return time (i.e. frequency) and hurricane intensity. The treatment-related change in carbon storage and fluxes were reported as changes in aboveground forest biomass (AGB), net primary productivity (NPP), and in the aboveground carbon partitioning components, or annual carbon accumulation (ACA). Increasing the frequency of hurricanes decreased aboveground biomass by between 5% and 39%, and increased NPP between 32% and 50%. Decadal-scale biomass fluctuations were damped relative to the control. In contrast, increasing hurricane intensity did not create a large shift in the long-term average forest structure, NPP, or ACA from that of historical hurricane regimes, but produced large fluctuations in biomass. Decreasing both the hurricane intensity and frequency by 50% produced the highest values of biomass and NPP. For the control scenario and with increased hurricane intensity, ACA was negative, which indicated that the aboveground forest components acted as a carbon source. However, with an increase in the frequency of storms or decreased storms, the total ACA was positive due to shifts in leaf production, annual litterfall, and coarse woody debris inputs, indicating a carbon sink into the

  3. African Dust Influence on Atlantic Hurricane Activity and the Peculiar Behaviour of Category 5 Hurricanes

    CERN Document Server

    Herrera, Victor M Velasco; H., Graciela Velasco; Gonzalez, Laura Luna

    2010-01-01

    We study the specific influence of African dust on each one of the categories of Atlantic hurricanes. By applying wavelet analysis, we find a strong decadal modulation of African dust on Category 5 hurricanes and an annual modulation on all other categories of hurricanes. We identify the formation of Category 5 hurricanes occurring mainly around the decadal minimum variation of African dust and in deep water areas of the Atlantic Ocean, where hurricane eyes have the lowest pressure. According to our results, future tropical cyclones will not evolve to Category 5 until the next decadal minimum that is, by the year 2015 +/- 2.

  4. Genesis and maintenance of "Mediterranean hurricanes"

    Directory of Open Access Journals (Sweden)

    K. Emanuel

    2005-01-01

    Full Text Available Cyclonic storms that closely resemble tropical cyclones in satellite images occasionally form over the Mediterranean Sea. Synoptic and mesoscale analyses of such storms show small, warm-core structure and surface winds sometimes exceeding 25ms-1 over small areas. These analyses, together with numerical simulations, reveal that in their mature stages, such storms intensify and are maintained by a feedback between surface enthalpy fluxes and wind, and as such are isomorphic with tropical cyclones. In this paper, I demonstrate that a cold, upper low over the Mediterranean can produce strong cyclogenesis in an axisymmetric model, thereby showing that baroclinic instability is not necessary during the mature stages of Mediterranean hurricanes.

  5. Increased Accuracy in Statistical Seasonal Hurricane Forecasting

    Science.gov (United States)

    Nateghi, R.; Quiring, S. M.; Guikema, S. D.

    2012-12-01

    Hurricanes are among the costliest and most destructive natural hazards in the U.S. Accurate hurricane forecasts are crucial to optimal preparedness and mitigation decisions in the U.S. where 50 percent of the population lives within 50 miles of the coast. We developed a flexible statistical approach to forecast annual number of hurricanes in the Atlantic region during the hurricane season. Our model is based on the method of Random Forest and captures the complex relationship between hurricane activity and climatic conditions through careful variable selection, model testing and validation. We used the National Hurricane Center's Best Track hurricane data from 1949-2011 and sixty-one candidate climate descriptors to develop our model. The model includes information prior to the hurricane season, i.e., from the last three months of the previous year (Oct. through Dec.) and the first five months of the current year (January through May). Our forecast errors are substantially lower than other leading forecasts such as that of the National Oceanic and Atmospheric Administration (NOAA).

  6. Gulf Coast Hurricanes Situation Report #39

    Energy Technology Data Exchange (ETDEWEB)

    None

    2005-11-09

    There are 49,300 customers without power in Florida as of 7:00 AM EST 11/9 due to Hurricane Wilma, down from a peak of about 3.6 million customers. Currently, less than 1 percent of the customers are without power in the state. This is the last report we will due on outages due to Hurricane Wilma.

  7. Hurricane impacts on US forest carbon sequestration

    Science.gov (United States)

    Steven G. McNulty

    2002-01-01

    Recent focus has been given to US forests as a sink for increases in atmospheric carbon dioxide. Current estimates of US Forest carbon sequestration average approximately 20 Tg (i.e. 1012 g) year. However, predictions of forest carbon sequestration often do not include the influence of hurricanes on forest carbon storage. Intense hurricanes...

  8. Genesis of tornadoes associated with hurricanes

    Science.gov (United States)

    Gentry, R. C.

    1983-01-01

    The climatological history of hurricane-tornadoes is brought up to date through 1982. Most of the tornadoes either form near the center of the hurricane, from the outer edge of the eyewall outward, or in an area between north and east-southeast of the hurricane center. The blackbody temperatures of the cloud tops which were analyzed for several hurricane-tornadoes that formed in the years 1974, 1975, and 1979, did not furnish strong precursor signals of tornado formation, but followed one of two patterns: either the temperatures were very low, or the tornado formed in areas of strong temperature gradients. Tornadoes with tropical cyclones most frequently occur at 1200-1800 LST, and although most are relatively weak, they can reach the F3 intensity level. Most form in association with the outer rainbands of the hurricane.

  9. The Ocean Boundary Layer beneath Hurricane Frances

    Science.gov (United States)

    Dasaro, E. A.; Sanford, T. B.; Terrill, E.; Price, J.

    2006-12-01

    The upper ocean beneath the peak winds of Hurricane Frances (57 m/s) was measured using several varieties of air-deployed floats as part of CBLAST. A multilayer structure was observed as the boundary layer deepened from 20m to 120m in about 12 hours. Bubbles generated by breaking waves create a 10m thick surface layer with a density anomaly, due to the bubbles, of about 1 kg/m3. This acts to lubricate the near surface layer. A turbulent boundary layer extends beneath this to about 40 m depth. This is characterized by large turbulent eddies spanning the boundary layer. A stratified boundary layer grows beneath this reaching 120m depth. This is characterized by a gradient Richardson number of 1/4, which is maintained by strong inertial currents generated by the hurricane, and smaller turbulent eddies driven by the shear instead of the wind and waves. There is little evidence of mixing beneath this layer. Heat budgets reveal the boundary layer to be nearly one dimensional through much of the deepening, with horizontal and vertical heat advection becoming important only after the storm had passed. Turbulent kinetic energy measurements support the idea of reduced surface drag at high wind speeds. The PWP model correctly predicts the degree of mixed layer deepening if the surface drag is reduced at high wind speed. Overall, the greatest uncertainty in understanding the ocean boundary layer at these extreme wind speeds is a characterization of the near- surface processes which govern the air-sea fluxes and surface wave properties.

  10. Hurricane Katrina deaths, Louisiana, 2005.

    Science.gov (United States)

    Brunkard, Joan; Namulanda, Gonza; Ratard, Raoult

    2008-12-01

    Hurricane Katrina struck the US Gulf Coast on August 29, 2005, causing unprecedented damage to numerous communities in Louisiana and Mississippi. Our objectives were to verify, document, and characterize Katrina-related mortality in Louisiana and help identify strategies to reduce mortality in future disasters. We assessed Hurricane Katrina mortality data sources received in 2007, including Louisiana and out-of-state death certificates for deaths occurring from August 27 to October 31, 2005, and the Disaster Mortuary Operational Response Team's confirmed victims' database. We calculated age-, race-, and sex-specific mortality rates for Orleans, St Bernard, and Jefferson Parishes, where 95% of Katrina victims resided and conducted stratified analyses by parish of residence to compare differences between observed proportions of victim demographic characteristics and expected values based on 2000 US Census data, using Pearson chi square and Fisher exact tests. We identified 971 Katrina-related deaths in Louisiana and 15 deaths among Katrina evacuees in other states. Drowning (40%), injury and trauma (25%), and heart conditions (11%) were the major causes of death among Louisiana victims. Forty-nine percent of victims were people 75 years old and older. Fifty-three percent of victims were men; 51% were black; and 42% were white. In Orleans Parish, the mortality rate among blacks was 1.7 to 4 times higher than that among whites for all people 18 years old and older. People 75 years old and older were significantly more likely to be storm victims (P Hurricane Katrina was the deadliest hurricane to strike the US Gulf Coast since 1928. Drowning was the major cause of death and people 75 years old and older were the most affected population cohort. Future disaster preparedness efforts must focus on evacuating and caring for vulnerable populations, including those in hospitals, long-term care facilities, and personal residences. Improving mortality reporting timeliness will

  11. Simulation of hurricane response to suppression of warm rain by sub-micron aerosols

    Directory of Open Access Journals (Sweden)

    D. Rosenfeld

    2007-04-01

    Full Text Available The feasibility of hurricane modification was investigated for hurricane Katrina using the Weather Research and Forecasting Model (WRF. The possible impact of seeding of clouds with submicron cloud condensation nuclei (CCN on hurricane structure and intensity as measured by nearly halving of the area covered by hurricane force winds was simulated by "turning–off" warm rain formation in the clouds at Katrina's periphery (where wind speeds were less than 22 m s−1. This simplification of the simulation of aerosol effects is aimed at evaluating the largest possible response. This resulted in the weakening of the hurricane surface winds compared to the "non-seeded" simulated storm during the first 24 h within the entire tropical cyclone (TC area compared to a control simulation without warm rain suppression. Later, the seeding-induced evaporative cooling at the TC periphery led to a shrinking of the eye and hence to some increase in the wind within the small central area of the TC. Yet, the overall strength of the hurricane decreased in response to the suppressed warm rain at the periphery, as measured by a 25% reduction in the radius of hurricane force winds. In a simulation with warm rain suppression throughout the hurricane, the relative weakening compared to the control continued throughout the simulations and the eye shrunk even further. This shows that the main mechanism by which suppressing warm rain weakens the TC is the low level evaporative cooling of the un-precipitated cloud drops and the added cooling due to melting of precipitation that falls from above.

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

    Science.gov (United States)

    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

  13. An Examination of Hurricane Emergency Preparedness Planning at Institutions of Higher Learning of the Gulf South Region Post Hurricane Katrina

    Science.gov (United States)

    Ventura, Caterina Gulli

    2010-01-01

    The purpose of the study was to examine hurricane emergency preparedness planning at institutions of higher learning of the Gulf South region following Hurricane Katrina. The problem addressed the impact of Hurricane Katrina on decision-making and policy planning processes. The focus was on individuals that administer the hurricane emergency…

  14. An Examination of Hurricane Emergency Preparedness Planning at Institutions of Higher Learning of the Gulf South Region Post Hurricane Katrina

    Science.gov (United States)

    Ventura, Caterina Gulli

    2010-01-01

    The purpose of the study was to examine hurricane emergency preparedness planning at institutions of higher learning of the Gulf South region following Hurricane Katrina. The problem addressed the impact of Hurricane Katrina on decision-making and policy planning processes. The focus was on individuals that administer the hurricane emergency…

  15. 78 FR 31614 - Implementation of Regulatory Guide 1.221 on Design-Basis Hurricane and Hurricane Missiles

    Science.gov (United States)

    2013-05-24

    ....221 on Design-Basis Hurricane and Hurricane Missiles AGENCY: Nuclear Regulatory Commission. ACTION... guidance regarding the application of Regulatory Guide (RG) 1.221, ``Design-Basis Hurricane and Hurricane... ML13015A688 Interim Staff Guidance-024 on Implementation of Regulatory Guide 1.221 on Design-Basis...

  16. Hurricane Katrina and perinatal health.

    Science.gov (United States)

    Harville, Emily W; Xiong, Xu; Buekens, Pierre

    2009-12-01

    We review the literature on the effects of Hurricane Katrina on perinatal health, and providing data from our own research on pregnant and postpartum women. After Katrina, obstetric, prenatal, and neonatal care was compromised in the short term, but increases in adverse birth outcomes such as preterm birth, low birthweight, and maternal complications were mostly limited to highly exposed women. Both pregnant and postpartum women had rates of post-traumatic stress disorder similar to, or lower than, others exposed to Katrina, and rates of depression similar to other pregnant and postpartum populations. Health behaviors, such as smoking and breastfeeding, may have been somewhat negatively affected by the disaster, whereas effects on nutrition were likely associated with limited time, money, and food choices, and indicated by both weight gain and loss. We conclude that, with a few specific exceptions, postdisaster concerns and health outcomes for pregnant and postpartum women were similar to those of other people exposed to Hurricane Katrina. In such situations, disaster planners and researchers should focus on providing care and support for the normal concerns of the peripartum period, such as breastfeeding, depression, and smoking cessation. Contraception needs to be available for those who do not want to become pregnant. Although additional physical and mental health care needs to be provided for the most severely exposed women and their babies, many women are capable of surviving and thriving in postdisaster environments.

  17. Recovery from PTSD following Hurricane Katrina.

    Science.gov (United States)

    McLaughlin, Katie A; Berglund, Patricia; Gruber, Michael J; Kessler, Ronald C; Sampson, Nancy A; Zaslavsky, Alan M

    2011-06-01

    We examined patterns and correlates of speed of recovery of estimated posttraumatic stress disorder (PTSD) among people who developed PTSD in the wake of Hurricane Katrina. A probability sample of prehurricane residents of areas affected by Hurricane Katrina was administered a telephone survey 7-19 months following the hurricane and again 24-27 months posthurricane. The baseline survey assessed PTSD using a validated screening scale and assessed a number of hypothesized predictors of PTSD recovery that included sociodemographics, prehurricane history of psychopathology, hurricane-related stressors, social support, and social competence. Exposure to posthurricane stressors and course of estimated PTSD were assessed in a follow-up interview. An estimated 17.1% of respondents had a history of estimated hurricane-related PTSD at baseline and 29.2% by the follow-up survey. Of the respondents who developed estimated hurricane-related PTSD, 39.0% recovered by the time of the follow-up survey with a mean duration of 16.5 months. Predictors of slow recovery included exposure to a life-threatening situation, hurricane-related housing adversity, and high income. Other sociodemographics, history of psychopathology, social support, social competence, and posthurricane stressors were unrelated to recovery from estimated PTSD. The majority of adults who developed estimated PTSD after Hurricane Katrina did not recover within 18-27 months. Delayed onset was common. Findings document the importance of initial trauma exposure severity in predicting course of illness and suggest that pre- and posttrauma factors typically associated with course of estimated PTSD did not influence recovery following Hurricane Katrina. © 2011 Wiley-Liss, Inc.

  18. The effect of proximity to hurricanes Katrina and Rita on subsequent hurricane outlook and optimistic bias.

    Science.gov (United States)

    Trumbo, Craig; Lueck, Michelle; Marlatt, Holly; Peek, Lori

    2011-12-01

    This study evaluated how individuals living on the Gulf Coast perceived hurricane risk after Hurricanes Katrina and Rita. It was hypothesized that hurricane outlook and optimistic bias for hurricane risk would be associated positively with distance from the Katrina-Rita landfall (more optimism at greater distance), controlling for historically based hurricane risk and county population density, demographics, individual hurricane experience, and dispositional optimism. Data were collected in January 2006 through a mail survey sent to 1,375 households in 41 counties on the coast (n = 824, 60% response). The analysis used hierarchal regression to test hypotheses. Hurricane history and population density had no effect on outlook; individuals who were male, older, and with higher household incomes were associated with lower risk perception; individual hurricane experience and personal impacts from Katrina and Rita predicted greater risk perception; greater dispositional optimism predicted more optimistic outlook; distance had a small effect but predicted less optimistic outlook at greater distance (model R(2) = 0.21). The model for optimistic bias had fewer effects: age and community tenure were significant; dispositional optimism had a positive effect on optimistic bias; distance variables were not significant (model R(2) = 0.05). The study shows that an existing measure of hurricane outlook has utility, hurricane outlook appears to be a unique concept from hurricane optimistic bias, and proximity has at most small effects. Future extension of this research will include improved conceptualization and measurement of hurricane risk perception and will bring to focus several concepts involving risk communication. © 2011 Society for Risk Analysis.

  19. Using Large-Eddy Simulations to Define Spectral and Coherence Characteristics of the Hurricane Boundary Layer for Wind-Energy Applications

    Science.gov (United States)

    Worsnop, Rochelle P.; Bryan, George H.; Lundquist, Julie K.; Zhang, Jun A.

    2017-06-01

    Offshore wind-energy development is planned for regions where hurricanes commonly occur, such as the USA Atlantic Coast. Even the most robust wind-turbine design (IEC Class I) may be unable to withstand a Category-2 hurricane (hub-height wind speeds >50 m s^{-1} ). Characteristics of the hurricane boundary layer that affect the structural integrity of turbines, especially in major hurricanes, are poorly understood, primarily due to a lack of adequate observations that span typical turbine heights (hurricane at high spatial (10 m) and temporal (0.1 s) resolution. By comparison with unique flight-level observations from a field project, we find that a relatively simple configuration of the Cloud Model I model accurately represents the properties of Hurricane Isabel (2003) in terms of mean wind speeds, wind-speed variances, and power spectra. Comparisons of power spectra and coherence curves derived from our hurricane simulations to those used in current turbine design standards suggest that adjustments to these standards may be needed to capture characteristics of turbulence seen within the simulated hurricane boundary layer. To enable improved design standards for wind turbines to withstand hurricanes, we suggest modifications to account for shifts in peak power to higher frequencies and greater spectral coherence at large separations.

  20. Gaussian and Lognormal Models of Hurricane Gust Factors

    Science.gov (United States)

    Merceret, Frank

    2009-01-01

    A document describes a tool that predicts the likelihood of land-falling tropical storms and hurricanes exceeding specified peak speeds, given the mean wind speed at various heights of up to 500 feet (150 meters) above ground level. Empirical models to calculate mean and standard deviation of the gust factor as a function of height and mean wind speed were developed in Excel based on data from previous hurricanes. Separate models were developed for Gaussian and offset lognormal distributions for the gust factor. Rather than forecasting a single, specific peak wind speed, this tool provides a probability of exceeding a specified value. This probability is provided as a function of height, allowing it to be applied at a height appropriate for tall structures. The user inputs the mean wind speed, height, and operational threshold. The tool produces the probability from each model that the given threshold will be exceeded. This application does have its limits. They were tested only in tropical storm conditions associated with the periphery of hurricanes. Winds of similar speed produced by non-tropical system may have different turbulence dynamics and stability, which may change those winds statistical characteristics. These models were developed along the Central Florida seacoast, and their results may not accurately extrapolate to inland areas, or even to coastal sites that are different from those used to build the models. Although this tool cannot be generalized for use in different environments, its methodology could be applied to those locations to develop a similar tool tuned to local conditions.

  1. Hurricanes

    Science.gov (United States)

    ... spawn tornadoes and lead to flooding. The high winds and heavy rains can destroy buildings, roads and bridges, and knock down power lines and trees. In coastal areas, very high tides called storm ...

  2. Hurricanes

    Science.gov (United States)

    ... Awareness Human Trafficking Awareness Month Holiday Stress Homeless Youth Awareness Month Bullying Prevention Domestic Violence Awareness Month Suicide Prevention Month/World Suicide Day Sept. 11th National ...

  3. Hurricane Katrina - Murphy Oil Spill Boundary

    Data.gov (United States)

    U.S. Environmental Protection Agency — Hurricane Katrina made landfall in August 2005, causing widespread devastation along the Gulf Coast of the United States. EPA emergency response personnel worked...

  4. Hurricane Sandy science plan: New York

    Science.gov (United States)

    Ransom, Clarice N.

    2013-01-01

    Hurricane Sandy is a stark reminder of why the Nation must become more resilient to coastal hazards. More than one-half of the U.S. population lives within 50 miles of a coast, and this number is increasing. The U.S. Geological Survey (USGS) is one of the largest providers of geologic and hydrologic information in the world. Federal, State, and local partners depend on the USGS science to know how to prepare for hurricane hazards and reduce losses from future hurricanes. The USGS works closely with other bureaus within the Department of the Interior, the Federal Emergency Management Agency, the National Oceanic Atmospheric Administration, the U.S. Army Corps of Engineers, the Environmental Protection Agency, and many State and local agencies to identify their information needs before, during, and after hurricanes.

  5. Evacuation Shelters - MDC_HurricaneShelter

    Data.gov (United States)

    NSGIC Local Govt | GIS Inventory — A label feature class of Miami-Dade County Hurricane Evacuation Shelters (HEC) including Special Need Evacuation Centers (SNEC) and Medical Management Facilities...

  6. Tsunamis and Hurricanes A Mathematical Approach

    CERN Document Server

    Cap, Ferdinand

    2006-01-01

    Tsunamis and hurricanes have had a devastating impact on the population living near the coast during the year 2005. The calculation of the power and intensity of tsunamis and hurricanes are of great importance not only for engineers and meteorologists but also for governments and insurance companies. This book presents new research on the mathematical description of tsunamis and hurricanes. A combination of old and new approaches allows to derive a nonlinear partial differential equation of fifth order describing the steepening up and the propagation of tsunamis. The description includes dissipative terms and does not contain singularities or two valued functions. The equivalence principle of solutions of nonlinear large gas dynamics waves and of solutions of water wave equations will be used. An extension of the continuity equation by a source term due to evaporation rates of salt seawater will help to understand hurricanes. Detailed formula, tables and results of the calculations are given.

  7. Final Gulf Coast Hurricanes Situation Report #46

    Energy Technology Data Exchange (ETDEWEB)

    None

    2006-01-26

    According to Entergy New Orleans, electricity has been restored to the vast majority of residents and businesses in the city, except in a few isolated areas that sustained severe devastation from Hurricane Katrina.

  8. Hurricane Irene Poster (August 27, 2011)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Hurricane Irene poster. Color composite GOES image shows Irene moving through the North Carolina Outer Banks on August 27, 2011. Poster size is 36"x27"

  9. Forecasting OctoberNovember Caribbean hurricane days

    National Research Council Canada - National Science Library

    Philip J. Klotzbach

    2011-01-01

      Late season Caribbean hurricane activity is predictable ENSO and the AWP show skill as predictors for OctNov Caribbean activity OctoberNovember Caribbean activity can significantly impact the US...

  10. Hurricane Katrina - Murphy Oil Spill Boundary

    Science.gov (United States)

    Hurricane Katrina made landfall in August 2005, causing widespread devastation along the Gulf Coast of the United States. EPA emergency response personnel worked with FEMA and state and local agencies to respond to the emergencies throughout the Gulf.

  11. Hurricane Matthew Takes Aim At Florida

    Science.gov (United States)

    ... plan for adequate supplies in case you lose power and water for several days and you are not able to leave due to flooding or blocked roads. Hurricane winds can cause trees and branches to fall, so trim or remove ...

  12. Evacuation Shelters - MDC_HurricaneShelter

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — A label feature class of Miami-Dade County Hurricane Evacuation Shelters (HEC) including Special Need Evacuation Centers (SNEC) and Medical Management Facilities...

  13. Drag Coefficient and Foam in Hurricane Conditions.

    Science.gov (United States)

    Golbraikh, E.; Shtemler, Y.

    2016-12-01

    he present study is motivated by recent findings of saturation and even decrease in the drag coefficient (capping) in hurricane conditions, which is accompanied by the production of a foam layer on the ocean surface. As it is difficult to expect at present a comprehensive numerical modeling of the drag coefficient saturation that is followed by wave breaking and foam production, there is no complete confidence and understanding of the saturation phenomenon. Our semi-empirical model is proposed for the estimation of the foam impact on the variation of the effective drag coefficient, Cd , with the reference wind speed U10 in stormy and hurricane conditions. The proposed model treats the efficient air-sea aerodynamic roughness length as a sum of two weighted aerodynamic roughness lengths for the foam-free and foam-covered conditions. On the available optical and radiometric measurements of the fractional foam coverage,αf, combined with direct wind speed measurements in hurricane conditions, which provide the minimum of the effective drag coefficient, Cd for the sea covered with foam. The present model yields Cd10 versus U10 in fair agreement with that evaluated from both open-ocean and laboratory measurements of the vertical variation of mean wind speed in the range of U10 from low to hurricane speeds. The present approach opens opportunities for drag coefficient modeling in hurricane conditions and hurricane intensity estimation by the foam-coverage value using optical and radiometric measurements.

  14. Improved understanding of near-ground winds in hurricanes and tornadoes

    Science.gov (United States)

    Karstens, Christopher Daniel

    Hurricanes and tornadoes contain the most destructive and life threatening winds on the planet. Combined, they are responsible for approximately $11 billion in damage in the U.S. annually. To compose a set of effective mitigation techniques, a comprehensive understanding of hurricane and tornado winds is needed. However, our understanding of these winds in the lowest 30 meters AGL, particularly their interaction with complex terrain, is lacking. This thesis includes two studies that address this issue. In the first study, a representative wind profile extracted from WRF simulations of hurricanes is used to initialize CFD modeled flow interaction with built structures using Fluent. The magnitude of structurally-induced modifications to the wind profile is presented. In the second study, recent tornado pressure and wind measurements are compared to laboratory and numerical simulations of tornado-like vortices. In addition, a comparative range of minimum pressures from a wide variety of tornadoes with different size and intensities is presented.

  15. An assessment of change in risk perception and optimistic bias for hurricanes among Gulf Coast residents.

    Science.gov (United States)

    Trumbo, Craig; Meyer, Michelle A; Marlatt, Holly; Peek, Lori; Morrissey, Bridget

    2014-06-01

    This study focuses on levels of concern for hurricanes among individuals living along the Gulf Coast during the quiescent two-year period following the exceptionally destructive 2005 hurricane season. A small study of risk perception and optimistic bias was conducted immediately following Hurricanes Katrina and Rita. Two years later, a follow-up was done in which respondents were recontacted. This provided an opportunity to examine changes, and potential causal ordering, in risk perception and optimistic bias. The analysis uses 201 panel respondents who were matched across the two mail surveys. Measures included hurricane risk perception, optimistic bias for hurricane evacuation, past hurricane experience, and a small set of demographic variables (age, sex, income, and education). Paired t-tests were used to compare scores across time. Hurricane risk perception declined and optimistic bias increased. Cross-lagged correlations were used to test the potential causal ordering between risk perception and optimistic bias, with a weak effect suggesting the former affects the latter. Additional cross-lagged analysis using structural equation modeling was used to look more closely at the components of optimistic bias (risk to self vs. risk to others). A significant and stronger potentially causal effect from risk perception to optimistic bias was found. Analysis of the experience and demographic variables' effects on risk perception and optimistic bias, and their change, provided mixed results. The lessening of risk perception and increase in optimistic bias over the period of quiescence suggest that risk communicators and emergency managers should direct attention toward reversing these trends to increase disaster preparedness. © 2013 Society for Risk Analysis.

  16. Hurricanes vs. Humans: Their Comparative Long-Term Effects on Tropical Landscapes.

    Science.gov (United States)

    Lugo, A. E.

    2002-12-01

    Puerto Rico experiences about 50 hurricanes per century. These large-scale events last for hours, but have significant short, medium, and long-term effects on vegetation and landscape processes as shown in studies in the Long-Term Ecological Research program. Forest canopy characteristics, tree mortality rates, life history characteristics of both plants and animals, successional rates, landslide occurrence, and sediment erosion and transport are examples of ecological and landscape attributes that exhibit strong responses to hurricane frequency and intensity. However, Puerto Rico has also undergone dramatic land cover change due to human activity. The island as a whole has experienced a cycle of deforestation, agricultural use, land abandonment, forest recovery, and urbanization. These anthropogenic events leave a long-term legacy on both individual ecosystems and the landscape as a whole. Species composition, structure, and age of forests are significantly influenced by human activity, as are rates of sediment erosion and transport, and frequency and size of landslides. I will present comparative data on the effects of hurricanes and human activity on Puerto Rico's forests and landscape. I address the following questions: which of these two forces that jointly shape the island's biota and landscape has a greater influence on functioning at the ecosystem level and what are the management implications? It appears that human impact on sediment erosion and transport events is greater than that of hurricanes and that humans change species composition of forests more than do hurricanes. However, regardless of the nature of the new ecosystems formed due to human activity, these systems must cope with the forces (rain and winds) of hurricanes in order to persist on the landscape. Regardless of the power of hurricanes, they don't appear to reset the human legacy on the island's landscape.

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

    Science.gov (United States)

    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.

  18. Validation of a probabilistic model for hurricane insurance loss projections in Florida

    Energy Technology Data Exchange (ETDEWEB)

    Pinelli, J.-P. [Florida Tech, Melbourne, Florida (United States)], E-mail: pinelli@fit.edu; Gurley, K.R. [University of Florida, Gainesville, Florida (United States); Subramanian, C.S. [Florida Tech, Melbourne, Florida (United States); Hamid, S.S. [Florida International University, Miami, Florida (United States); Pita, G.L. [Florida Tech, Melbourne, Florida (United States)

    2008-12-15

    The Florida Public Hurricane Loss Model is one of the first public models accessible for scrutiny to the scientific community, incorporating state of the art techniques in hurricane and vulnerability modeling. The model was developed for Florida, and is applicable to other hurricane-prone regions where construction practice is similar. The 2004 hurricane season produced substantial losses in Florida, and provided the means to validate and calibrate this model against actual claim data. This paper presents the predicted losses for several insurance portfolios corresponding to hurricanes Andrew, Charley, and Frances. The predictions are validated against the actual claim data. Physical damage predictions for external building components are also compared to observed damage. The analyses show that the predictive capabilities of the model were substantially improved after the calibration against the 2004 data. The methodology also shows that the predictive capabilities of the model could be enhanced if insurance companies report more detailed information about the structures they insure and the types of damage they suffer. This model can be a powerful tool for the study of risk reduction strategies.

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

    Science.gov (United States)

    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.

  20. Hurricanes in an Aquaplanet World: Implications of the Impacts of External Forcing and Model Horizontal Resolution

    Energy Technology Data Exchange (ETDEWEB)

    Li, Fuyu; Collins, William D.; Wehner, Michael F.; Leung, Lai-Yung R.

    2013-06-02

    High-resolution climate models have been shown to improve the statistics of tropical storms and hurricanes compared to low-resolution models. The impact of increasing horizontal resolution in the tropical storm simulation is investigated exclusively using a series of Atmospheric Global Climate Model (AGCM) runs with idealized aquaplanet steady-state boundary conditions and a fixed operational storm-tracking algorithm. The results show that increasing horizontal resolution helps to detect more hurricanes, simulate stronger extreme rainfall, and emulate better storm structures in the models. However, increasing model resolution does not necessarily produce stronger hurricanes in terms of maximum wind speed, minimum sea level pressure, and mean precipitation, as the increased number of storms simulated by high-resolution models is mainly associated with weaker storms. The spatial scale at which the analyses are conducted appears to have more important control on these meteorological statistics compared to horizontal resolution of the model grid. When the simulations are analyzed on common low-resolution grids, the statistics of the hurricanes, particularly the hurricane counts, show reduced sensitivity to the horizontal grid resolution and signs of scale invariant.

  1. Disaster prevention design criteria for the estuarine cities:New Orleans and Shanghai The lesson from Hurricane Katrina

    Institute of Scientific and Technical Information of China (English)

    LIU Defu; SHI Hongda; PANG Liang

    2006-01-01

    The accurate prediction of the typhoon (hurricane) induced extreme sea environments is very important for the coastal structure design in areas influenced by typhoon (hurricane). In 2005 Hurricane Katrina brought a severe catastrophe in New Orleans by combined effects of hurricane induced extreme sea environments and upper flood of the Mississippi River. Like the New Orleans City, Shanghai is located at the estuarine area of the Changjiang River and the combined effect of typhoon induced extreme sea environments, flood peak runoff from the Changjiang River coupled with the spring tide is the dominate factor for disaster prevention design criteria. The Poisson-nested logistic trivariate compound extreme value distribution (PNLTCEVD) is a new type of joint probability model which is proposed by compounding a discrete distribution (typhoon occurring frequency) into a continuous multivariate joint distribution (typhoon induced extreme events). The new model gives more reasonable predicted results for New Orleans and Shanghai disaster prevention design criteria.

  2. 2005 Significant U.S. Hurricane Strikes Poster

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The 2005 Significant U.S. Hurricane Strikes poster is one of two special edition posters for the Atlantic Hurricanes. This beautiful poster contains two sets of...

  3. Tracks of Major Hurricanes of the Western Hemisphere

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This 36"x24" National Hurricane Center poster depicts the complete tracks of all major hurricanes in the north Atlantic and eastern north Pacific basins since as...

  4. Identification of Caribbean basin hurricanes from Spanish documentary sources

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Herrera, R. [Depto. Fisica de la Tierra II, Facultad de Ciencias Fisicas, Universidad Complutense de Madrid, Ciudad Universitaria, 28040 Madrid (Spain); Gimeno, L. [Universidad de Vigo, Ourense (Spain); Ribera, P.; Gonzalez, E.; Fernandez, G. [Universidad Pablo de Olavide, Sevilla (Spain); Hernandez, E. [Universidad Complutense de Madrid, Madrid (Spain)

    2007-07-15

    This paper analyses five hurricanes that occurred in the period 1600 to 1800. These examples were identified during a systematic search in the General Archive of the Indies (AGI) in Seville. The research combined the expertise of climatologists and historians in order to optimise the search and analysis strategies. Results demonstrate the potential of this archive for the assessment of hurricanes in this period and show some of the difficulties involved in the collection of evidence of hurricane activity. The documents provide detailed descriptions of a hurricane's impacts and allow us to identify previously unreported hurricanes, obtain more precise dates for hurricanes previously identified, better define the area affected by a given hurricane and, finally, better assess a hurricane's intensity.

  5. Continental United States Hurricane Strikes 1950-2012

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Continental U.S. Hurricane Strikes Poster is our most popular poster which is updated annually. The poster includes all hurricanes that affected the U.S. since...

  6. Child mortality after Hurricane Katrina.

    Science.gov (United States)

    Kanter, Robert K

    2010-03-01

    Age-specific pediatric health consequences of community disruption after Hurricane Katrina have not been analyzed. Post-Katrina vital statistics are unavailable. The objectives of this study were to validate an alternative method to estimate child mortality rates in the greater New Orleans area and compare pre-Katrina and post-Katrina mortality rates. Pre-Katrina 2004 child mortality was estimated from death reports in the local daily newspaper and validated by comparison with pre-Katrina data from the Louisiana Department of Health. Post-Katrina child mortality rates were analyzed as a measure of health consequences. Newspaper-derived estimates of mortality rates appear to be valid except for possible underreporting of neonatal rates. Pre-Katrina and post-Katrina mortality rates were similar for all age groups except infants. Post-Katrina, a 92% decline in mortality rate occurred for neonates (Katrina decline in infant mortality rate exceeds the pre-Katrina discrepancy between newspaper-derived and Department of Health-reported rates. A declining infant mortality rate raises questions about persistent displacement of high-risk infants out of the region. Otherwise, there is no evidence of long-lasting post-Katrina excess child mortality. Further investigation of demographic changes would be of interest to local decision makers and planners for recovery after public health emergencies in other regions.

  7. Cold wake of Hurricane Frances

    Science.gov (United States)

    D'Asaro, Eric A.; Sanford, Thomas B.; Niiler, P. Peter; Terrill, Eric J.

    2007-08-01

    An array of instruments air-deployed ahead of Hurricane Frances measured the three-dimensional, time dependent response of the ocean to this strong (60 ms-1) storm. Sea surface temperature cooled by up to 2.2°C with the greatest cooling occurring in a 50-km-wide band centered 60-85 km to the right of the track. The cooling was almost entirely due to vertical mixing, not air-sea heat fluxes. Currents of up to 1.6 ms-1 and thermocline displacements of up to 50 m dispersed as near-inertial internal waves. The heat in excess of 26°C, decreased behind the storm due primarily to horizontal advection of heat away from the storm track, with a small contribution from mixing across the 26°C isotherm. SST cooling under the storm core (0.4°C) produced a 16% decrease in air-sea heat flux implying an approximately 5 ms-1 reduction in peak winds

  8. A prospective study of religiousness and psychological distress among female survivors of Hurricanes Katrina and Rita.

    Science.gov (United States)

    Chan, Christian S; Rhodes, Jean E; Pérez, John E

    2012-03-01

    This prospective study examined the pathways by which religious involvement affected the post-disaster psychological functioning of women who survived Hurricanes Katrina and Rita. The participants were 386 low-income, predominantly Black, single mothers. The women were enrolled in the study before the hurricane, providing a rare opportunity to document changes in mental health from before to after the storm, and to assess the protective role of religious involvement over time. Results of structural equation modeling indicated that, controlling for level of exposure to the hurricanes, pre-disaster physical health, age, and number of children, pre-disaster religiousness predicted higher levels of post-disaster (1) social resources and (2) optimism and sense of purpose. The latter, but not the former, was associated with better post-disaster psychological outcome. Mediation analysis confirmed the mediating role of optimism and sense of purpose.

  9. Determining Key Model Parameters of Rapidly Intensifying Hurricane Guillermo(1997) using the Ensemble Kalman Filter

    CERN Document Server

    Godinez, Humberto C; Fierro, Alexandre O; Guimond, Stephen R; Kao, Jim

    2011-01-01

    In this work we present the assimilation of dual-Doppler radar observations for rapidly intensifying hurricane Guillermo (1997) using the Ensemble Kalman Filter (EnKF) to determine key model parameters. A unique aspect of Guillermo was that during the period of radar observations strong convective bursts, attributable to wind shear, formed primarily within the eastern semicircle of the eyewall. To reproduce this observed structure within a hurricane model, background wind shear of some magnitude must be specified; as well as turbulence and surface parameters appropriately specified so that the impact of the shear on the simulated hurricane vortex can be realized. To first illustrate the complex nonlinear interactions induced by changes in these parameters, an ensemble of 120 simulations have been conducted in which individual members were formulated by sampling the parameters within a certain range via a Latin hypercube approach. Next, data from the 120 simulations and two distinct derived fields of observati...

  10. Mediating the Morals of Disasters: Hurricane Katrina in Norwegian News Media

    Directory of Open Access Journals (Sweden)

    Kyrre Kverndokk

    2014-06-01

    Full Text Available The Norwegian media responses to Hurricane Katrina were structured around three well-established sets of motifs in a globalized late modern disaster discourse: 1 The collapse of civil society, 2 Social vulnerability 2 Extreme weather and global warming. These sets of motifs portray relationships or non-relationships between natural evil and moral evil. Starting with Voltaire’s description of Candide’s arrival in Lisbon after the earthquake I discuss how an 18th century disaster discourse is echoed in contemporary media narratives. This paper explores a folkloristic and narratological approach to writing nature. I use Hurricane Katrina as a case for studying Norwegian media disaster narratives. In these narratives I am concerned with how such narratives transform disasters from being acts of nature to become issues of morale. Modern disaster narratives have more complex historical roots then often claimed. This complexity is mirrored in the media representations of Hurricane Katrina.

  11. The impact of Hurricanes Gustav and Ike on offshore oil and gas production in the Gulf of Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Kaiser, Mark J.; Yu, Yunke [Center for Energy Studies, Louisiana State University, Energy Coast and Environment Building, Nicholson Extension Drive, Baton Rouge, LA 70803 (United States)

    2010-01-15

    During August and September 2008, Hurricanes Gustav and Ike passed through the Gulf of Mexico and damaged and destroyed a number of offshore oil and gas structures. In the final official government assessment, a total of 60 platforms were destroyed and 31 structures were identified as having extensive damage. The destroyed platforms were responsible for about 1.6% of the oil and 2.5% of the gas produced daily in the Gulf of Mexico and represented approximately 234 million BOE of reserves valued between 4.6 and 10.9 billion. Although the number of structures destroyed by Hurricanes Gustav and Ike was half the total destruction from the 2004-2005 hurricane seasons, we estimate that the reserves at risk are approximately three times more valuable. Each destroyed structure is unique in its production capacity and damages incurred and are a candidate for redevelopment. We review pre-hurricane production and revenue characteristics for the collection of destroyed structures and estimate production at risk. Gas structures are expected to present better economics and redevelopment potential than oil structures, and we predict that 198 million BOE, or nearly 95% of reserves-in-place, are likely to be redeveloped. Shut-in production statistics are compared against recent hurricane events and general comments on the factors involved in decision making are presented. (author)

  12. Prototype of an Integrated Hurricane Information System for Research: Design and Implementation of the Database and Web Portal

    Science.gov (United States)

    Li, P. P.; Knosp, B.; Vu, Q. A.; Hristova-Veleva, S.; Chao, Y.; Vane, D.; Lambrigtsen, B.; Su, H.; Dang, V.; Fovell, R.; Willis, J.; Tanelli, S.; Fishbein, E.; Ao, C. O.; Poulsen, W. L.; Park, K. J.; Fetzer, E.; Vazquez, J.; Callahan, P. S.; Marcus, S.; Garay, M.; Kahn, R.; Haddad, Z.

    2007-12-01

    Many hurricane websites provide historical hurricane information and real-time storm tracking. These sites often include images from various remote-sensing satellite sensors with such atmospheric and oceanic quantities as wind, temperature, rain, and water vapor. However, it has been determined that the hurricane analysis community is lacking a web portal that provides researchers a comprehensive set of observed hurricane parameters (both graphics and data) together with large-scale and convection-resolving model output. We have developed a prototype of an integrated hurricane information system of high-resolution satellite and in- situ observations along with model outputs pertaining to: i) the thermodynamic and microphysical structure of storms; ii) the air-sea interaction processes; iii) the larger-scale environment as depicted by quantities such as SST, ocean heat content and the aerosol loading of the environment. Our goal is to provide a one-stop place to access all the available information of a specific hurricane for researchers to advance the understanding, modeling and predication of hurricane genesis and intensity changes. Our hurricane information system prototype consists of high-resolution satellite data measuring three- dimensional atmospheric and oceanic parameters that includes observations from AIRS, MISR, MODIS, CloudSAT, AMSR-E, TRMM, GOES, MLS, QuikSCAT, SeaWiFS, and COSMIC GPS, in-situ observations such as ARGO floats, large scale data assimilation products from NCEP, and high resolution hurricane model output from WRF. High-resolution satellite data are sub-setted within 2000-kilometer-square area centered at the closest storm location and large-scale environmental datasets are divided into 6 predefined geographical regions. When accessing this hurricane portal, users may browse through data by year, region, category, and hurricane. At the front page, we show the hurricane track using Google Map. Users may pan and zoom, or click on the track

  13. Increase in West Nile neuroinvasive disease after Hurricane Katrina.

    Science.gov (United States)

    Caillouët, Kevin A; Michaels, Sarah R; Xiong, Xu; Foppa, Ivo; Wesson, Dawn M

    2008-05-01

    After Hurricane Katrina, the number of reported cases of West Nile neuroinvasive disease (WNND) sharply increased in the hurricane-affected regions of Louisiana and Mississippi. In 2006, a >2-fold increase in WNND incidence was observed in the hurricane-affected areas than in previous years.

  14. Increase in West Nile Neuroinvasive Disease after Hurricane Katrina

    OpenAIRE

    Caillou?t, Kevin A.; Michaels, Sarah R.; Xiong, Xu; Foppa, Ivo; Wesson, Dawn M.

    2008-01-01

    After Hurricane Katrina, the number of reported cases of West Nile neuroinvasive disease (WNND) sharply increased in the hurricane-affected regions of Louisiana and Mississippi. In 2006, a >2-fold increase in WNND incidence was observed in the hurricane-affected areas than in previous years.

  15. Community College Re-Enrollment after Hurricane Katrina

    Science.gov (United States)

    Lowe, Sarah R.; Rhodes, Jean E.

    2013-01-01

    In this study, we explored predictors of community college re-enrollment after Hurricane Katrina among a sample of low-income women (N = 221). It was predicted that participants' pre-hurricane educational optimism would predict community college re-enrollment a year after the hurricane. The influence of various demographic and additional resources…

  16. Secondary Eyewall Formation in Two Idealized, Full-Physics Modeled Hurricanes

    Science.gov (United States)

    2008-06-26

    28C. The upper boundary is closed, but includes a Rayleigh ‘‘ sponge ’’ layer exclusively in the stratosphere (uppermost six levels) to strongly damp...A. (2002), A cloud-resolving simulation of Hurricane Bob (1991): Storm structure and eyewall buoyancy, Mon. Weather Rev., 130, 1573–1592. Braun, S

  17. Hurricanes, coral reefs and rainforests: resistance, ruin and recovery in the Caribbean

    Science.gov (United States)

    2000-01-01

    The coexistence of hurricanes, coral reefs, and rainforests in the Caribbean demonstrates that highly structured ecosystems with great diversity can flourish in spite of recurring exposure to intense destructive energy. Coral reefs develop in response to wave energy and resist hurricanes largely by virtue of their structural strength. Limited fetch also protects some reefs from fully developed hurricane waves. While storms may produce dramatic local reef damage, they appear to have little impact on the ability of coral reefs to provide food or habitat for fish and other animals. Rainforests experience an enormous increase in wind energy during hurricanes with dramatic structural changes in the vegetation. The resulting changes in forest microclimate are larger than those on reefs and the loss of fruit, leaves, cover, and microclimate has a great impact on animal populations. Recovery of many aspects of rainforest structure and function is rapid, though there may be long-term changes in species composition. While resistance and repair have maintained reefs and rainforests in the past, human impacts may threaten their ability to survive.

  18. The Department of Defense and Homeland Security relationship: Hurricane Katrina through Hurricane Irene.

    Science.gov (United States)

    Weaver, John Michael

    2015-01-01

    This research explored federal intervention with the particular emphasis on examining how a collaborative relationship between Department of Defense (DOD) and Homeland Security (DHS) led to greater effectiveness between these two federal departments and their subordinates (United States Northern Command and Federal Emergency Management Agency, respectively) during the preparation and response phases of the disaster cycle regarding US continental-based hurricanes. Through the application of a two-phased, sequential mixed methods approach, this study determined how their relationship has led to longitudinal improvements in the years following Hurricane Katrina, focusing on hurricanes as the primary unit of analysis.

  19. Hurricane Katrina: addictive behavior trends and predictors.

    Science.gov (United States)

    Beaudoin, Christopher E

    2011-01-01

    Post-disaster trends in alcohol consumption and cigarette smoking, as well as their predictors, were identified. Methods. Data from cross-sectional and panel surveys of African American adults in New Orleans, Louisiana, were used from before (2004: n = 1,867; 2005: n = 879) and after (2006a: n = 500; 2006b: n = 500) Hurricane Katrina. Alcohol consumption increased significantly from pre- to post-Hurricane Katrina, while cigarette smoking remained constant. In 2006, posttraumatic stress disorder (PTSD) was associated with cigarette smoking, whereas "news attention" and "provided social support" were inversely associated with cigarette smoking. "News attention" was also inversely associated with cigarette smoking frequency, while "neighborliness" was associated with alcohol consumption. In addition, the effects of PTSD on alcohol consumption were moderated by "neighborliness." In the wake of Hurricane Katrina, there were complex predictive processes of addictive behaviors involving PTSD, news information, and social capital-related measures.

  20. Worldwide historical hurricane tracks from 1848 through the previous hurricane season

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This Historical Hurricane Tracks web site provides visualizations of storm tracks derived from the 6-hourly (0000, 0600, 1200, 1800 UTC) center locations and...

  1. Hurricane Charley Exposure and Hazard of Preterm Delivery, Florida 2004.

    Science.gov (United States)

    Grabich, Shannon C; Robinson, Whitney R; Engel, Stephanie M; Konrad, Charles E; Richardson, David B; Horney, Jennifer A

    2016-12-01

    Objective Hurricanes are powerful tropical storm systems with high winds which influence many health effects. Few studies have examined whether hurricane exposure is associated with preterm delivery. We aimed to estimate associations between maternal hurricane exposure and hazard of preterm delivery. Methods We used data on 342,942 singleton births from Florida Vital Statistics Records 2004-2005 to capture pregnancies at risk of delivery during the 2004 hurricane season. Maternal exposure to Hurricane Charley was assigned based on maximum wind speed in maternal county of residence. We estimated hazards of overall preterm delivery (<37 gestational weeks) and extremely preterm delivery (<32 gestational weeks) in Cox regression models, adjusting for maternal/pregnancy characteristics. To evaluate heterogeneity among racial/ethnic subgroups, we performed analyses stratified by race/ethnicity. Additional models investigated whether exposure to multiples hurricanes increased hazard relative to exposure to one hurricane. Results Exposure to wind speeds ≥39 mph from Hurricane Charley was associated with a 9 % (95 % CI 3, 16 %) increase in hazard of extremely preterm delivery, while exposure to wind speed ≥74 mph was associated with a 21 % (95 % CI 6, 38 %) increase. Associations appeared greater for Hispanic mothers compared to non-Hispanic white mothers. Hurricane exposure did not appear to be associated with hazard of overall preterm delivery. Exposure to multiple hurricanes did not appear more harmful than exposure to a single hurricane. Conclusions Hurricane exposure may increase hazard of extremely preterm delivery. As US coastal populations and hurricane severity increase, the associations between hurricane and preterm delivery should be further studied.

  2. Geologic hazards in the region of the Hurricane fault

    Science.gov (United States)

    Lund, W.R.

    1997-01-01

    common in southwestern Utah where it has damaged roads, canal embankments, and water-retention structures. Several unexplained sinkholes near the town of Hurricane possibly are the result of collapse of subsurface volcanic features. Geologic formations associated with slope failures along or near the Hurricane fault include rocks of both Mesozoic and Tertiary age. Numerous landslides are present in these materials along the Hurricane Cliffs, and the Petrified Forest Member of the Chinle Formation is commonly associated with slope failures where it crops out in the St. George Basin. Steep slopes and numerous areas of exposed bedrock make rock fall a hazard in the St. George Basin. Debris flows and debris floods in narrow canyons and on alluvial fans often accompany intense summer cloudburst thunderstorms. Flooded basements and foundation problems associated with shallow ground water are common on benches north of the Santa Clara River in the city of Santa Clara. Stream flooding is the most frequently occurring and destructive geologic hazard in southwestern Utah. Since the 1850s, there have been three major riverine (regional) floods and more than 300 damaging flash floods. Although a variety of flood control measures have been implemented, continued rapid growth in the region is again increasing vulnerability to flood hazards. Site-specific studies to evaluate geologic hazards and identify hazard-reduction measures are recommended prior to construction to reduce the need for costly repair, maintenance, or replacement of improperly placed or protected facilities.

  3. Hurricane names: A bunch of hot air?

    Directory of Open Access Journals (Sweden)

    Gary Smith

    2016-06-01

    Full Text Available It has been argued that female-named hurricanes are deadlier because people do not take them seriously. However, this conclusion is based on a questionable statistical analysis of a narrowly defined data set. The reported relationship is not robust in that it is not confirmed by a straightforward analysis of more inclusive data or different data.

  4. Wind and waves in extreme hurricanes

    NARCIS (Netherlands)

    Holthuijsen, L.H.; Powell, M.D.; Pietrzak, J.D.

    2012-01-01

    Waves breaking at the ocean surface are important to the dynamical, chemical and biological processes at the air-sea interface. The traditional view is that the white capping and aero-dynamical surface roughness increase with wind speed up to a limiting value. This view is fundamental to hurricane

  5. Economic impacts of hurricanes on forest owners

    Science.gov (United States)

    Jeffrey P. Prestemon; Thomas P. Holmes

    2010-01-01

    We present a conceptual model of the economic impacts of hurricanes on timber producers and consumers, offer a framework indicating how welfare impacts can be estimated using econometric estimates of timber price dynamics, and illustrate the advantages of using a welfare theoretic model, which includes (1) welfare estimates that are consistent with neo-classical...

  6. Investigation of long-term hurricane activity

    NARCIS (Netherlands)

    Nguyen, B.M.; Van Gelder, P.H.A.J.M.

    2012-01-01

    This paper presents a new approach of applying numerical methods to model storm processes. A storm empirical track technique is utilized to simulate the full tracks of hurricanes, starting with their initial points over the sea and ending with their landfall locations or final dissipations. The

  7. Hurricane Ike versus an Atomic Bomb

    Science.gov (United States)

    Pearson, Earl F.

    2013-01-01

    The destructive potential of one of nature's most destructive forces, the hurricane, is compared to one of human's most destructive devices, an atomic bomb. Both can create near absolute devastation at "ground zero". However, how do they really compare in terms of destructive energy? This discussion compares the energy, the…

  8. Rapid mapping of hurricane damage to forests

    Science.gov (United States)

    Erik M. Nielsen

    2009-01-01

    The prospects for producing rapid, accurate delineations of the spatial extent of forest wind damage were evaluated using Hurricane Katrina as a test case. A damage map covering the full spatial extent of Katrina?s impact was produced from Moderate Resolution Imaging Spectroradiometer (MODIS) satellite imagery using higher resolution training data. Forest damage...

  9. The economics and ethics of Hurricane Katrina.

    Science.gov (United States)

    Rockwell, Llewellyn H; Block, Walter E

    2010-01-01

    How might free enterprise have dealt with Hurricane Katrina and her aftermath. This article probes this question at increasing levels of radicalization, starting with the privatization of several government “services” and ending with the privatization of all of them.

  10. Gulf Coast Hurricanes Situation Report #40

    Energy Technology Data Exchange (ETDEWEB)

    None

    2005-11-14

    On 11/12 Florida Power & Light (FPL) announced that crews had essentially completed Hurricane Wilma restoration efforts to all 3.2 million customers in South Florida who had been without power. Electricity restoration efforts are now essentially complete in Florida.

  11. Hurricanes as Heat Engines: Two Undergraduate Problems

    Science.gov (United States)

    Pyykko, Pekka

    2007-01-01

    Hurricanes can be regarded as Carnot heat engines. One reason that they can be so violent is that thermodynamically, they demonstrate large efficiency, [epsilon] = (T[subscript h] - T[subscript c]) / T[subscript h], which is of the order of 0.3. Evaporation of water vapor from the ocean and its subsequent condensation is the main heat transfer…

  12. Evacuating the Area of a Hurricane

    Centers for Disease Control (CDC) Podcasts

    2006-08-10

    If a hurricane warning is issued for your area, or authorities tell you to evacuate, take only essential items. If you have time, turn off gas, electricity, and water and disconnect appliances.  Created: 8/10/2006 by Emergency Communications System.   Date Released: 10/10/2007.

  13. Wind and waves in extreme hurricanes

    NARCIS (Netherlands)

    Holthuijsen, L.H.; Powell, M.D.; Pietrzak, J.D.

    2012-01-01

    Waves breaking at the ocean surface are important to the dynamical, chemical and biological processes at the air-sea interface. The traditional view is that the white capping and aero-dynamical surface roughness increase with wind speed up to a limiting value. This view is fundamental to hurricane f

  14. Wind and waves in extreme hurricanes

    NARCIS (Netherlands)

    Holthuijsen, L.H.; Powell, M.D.; Pietrzak, J.D.

    2012-01-01

    Waves breaking at the ocean surface are important to the dynamical, chemical and biological processes at the air-sea interface. The traditional view is that the white capping and aero-dynamical surface roughness increase with wind speed up to a limiting value. This view is fundamental to hurricane f

  15. Investigation of long-term hurricane activity

    NARCIS (Netherlands)

    Nguyen, B.M.; Van Gelder, P.H.A.J.M.

    2012-01-01

    This paper presents a new approach of applying numerical methods to model storm processes. A storm empirical track technique is utilized to simulate the full tracks of hurricanes, starting with their initial points over the sea and ending with their landfall locations or final dissipations. The theo

  16. Preparing for a Hurricane: Prescription Medications

    Centers for Disease Control (CDC) Podcasts

    2006-08-10

    What you should do to protect yourself and your family from a hurricane. As you evacuate, remember to take your prescription medicines with you.  Created: 8/10/2006 by Emergency Communications System.   Date Released: 7/17/2008.

  17. Hurricane Ike versus an Atomic Bomb

    Science.gov (United States)

    Pearson, Earl F.

    2013-01-01

    The destructive potential of one of nature's most destructive forces, the hurricane, is compared to one of human's most destructive devices, an atomic bomb. Both can create near absolute devastation at "ground zero". However, how do they really compare in terms of destructive energy? This discussion compares the energy, the…

  18. Elements of extreme wind modeling for hurricanes

    DEFF Research Database (Denmark)

    Larsen, Søren Ejling; Ejsing Jørgensen, Hans; Kelly, Mark C.;

    The report summarizes characteristics of the winds associated with Tropical Cyclones (Hurricanes, Typhoons). It has been conducted by the authors across several years, from 2012-2015, to identify the processes and aspects that one should consider when building at useful computer support system...

  19. Atlantic Hurricane Activity: 1851-1900

    Science.gov (United States)

    Landsea, C. W.

    2001-12-01

    This presentation reports on the second year's work of a three year project to re-analyze the North Atlantic hurricane database (or HURDAT). The original database of six-hourly positions and intensities were put together in the 1960s in support of the Apollo space program to help provide statistical track forecast guidance. In the intervening years, this database - which is now freely and easily accessible on the Internet from the National Hurricane Center's (NHC's) Webpage - has been utilized for a wide variety of uses: climatic change studies, seasonal forecasting, risk assessment for county emergency managers, analysis of potential losses for insurance and business interests, intensity forecasting techniques and verification of official and various model predictions of track and intensity. Unfortunately, HURDAT was not designed with all of these uses in mind when it was first put together and not all of them may be appropriate given its original motivation. One problem with HURDAT is that there are numerous systematic as sell as some random errors in the database which need correction. Additionally, analysis techniques have changed over the years at NHC as our understanding of tropical cyclones has developed, leading to biases in the historical database that have not been addressed. Another difficulty in applying the hurricane database to studies concerned with landfalling events is the lack exact location, time and intensity at hurricane landfall. Finally, recent efforts into uncovering undocumented historical hurricanes in the late 1800s and early 1900s led by Jose Fernandez-Partagas have greatly increased our knowledge of these past events, which are not yet incorporated into the HURDAT database. Because of all of these issues, a re-analysis of the Atlantic hurricane database is being attempted that will be completed in three years. As part of the re-analyses, three files will be made available: {* } The revised Atlantic HURDAT (with six hourly intensities

  20. MUNICIPAL ENVIRONMENTAL MANAGEMENT: INSTITUTIONAL SITUATION ANALYSIS IN MUNICIPALITIES AFFECTED BY NATURAL DISASTERS – THE CASE OF THE HURRICANE CATARINA

    Directory of Open Access Journals (Sweden)

    Roberta do Espírito Santo Luzzardi

    2011-06-01

    Full Text Available This article seeks to analyze the current situation and environmental management structure of the municipalities affected by the first hurricane of the South Atlantic, the Hurricane Catarina, five years after its occurrence. In this way, we tried to verify to what extent the awareness of global threats, such as climate changes and the consequent natural disasters, increases the predisposition of institutional improvement related to the environment in municipalities. Therefore, we visited all municipalities affected by the hurricane with impact of damage classified as medium, high or very high. Based on primary and secondary data, we 211 sought to compare the environmental management structure at the time of the occurrence of the disaster and current structure. As conclusion, it is possible to say that little has changed in terms of municipal environmental management, even after 5 years of the phenomenon.

  1. Impact of Hurricane Exposure on Reproductive Health Outcomes, Florida, 2004.

    Science.gov (United States)

    Grabich, Shannon C; Robinson, Whitney R; Konrad, Charles E; Horney, Jennifer A

    2017-08-01

    Prenatal hurricane exposure may be an increasingly important contributor to poor reproductive health outcomes. In the current literature, mixed associations have been suggested between hurricane exposure and reproductive health outcomes. This may be due, in part, to residual confounding. We assessed the association between hurricane exposure and reproductive health outcomes by using a difference-in-difference analysis technique to control for confounding in a cohort of Florida pregnancies. We implemented a difference-in-difference analysis to evaluate hurricane weather and reproductive health outcomes including low birth weight, fetal death, and birth rate. The study population for analysis included all Florida pregnancies conceived before or during the 2003 and 2004 hurricane season. Reproductive health data were extracted from vital statistics records from the Florida Department of Health. In 2004, 4 hurricanes (Charley, Frances, Ivan, and Jeanne) made landfall in rapid succession; whereas in 2003, no hurricanes made landfall in Florida. Overall models using the difference-in-difference analysis showed no association between exposure to hurricane weather and reproductive health. The inconsistency of the literature on hurricane exposure and reproductive health may be in part due to biases inherent in pre-post or regression-based county-level comparisons. We found no associations between hurricane exposure and reproductive health. (Disaster Med Public Health Preparedness. 2017;11:407-411).

  2. Identification and structural characterization of a sialylated lacto-N-neotetraose structure in the lipopolysaccharide of Haemophilus influenzae.

    Science.gov (United States)

    Cox, Andrew D; Hood, Derek W; Martin, Adele; Makepeace, Katherine M; Deadman, Mary E; Li, Jianjun; Brisson, Jean-Robert; Moxon, E Richard; Richards, James C

    2002-08-01

    A sialylated lacto-N-neotetraose (Sial-lNnT) structural unit was identified and structurally characterized in the lipopolysaccharide (LPS) from the genome-sequenced strain Rd [corrected] (RM118) of the human pathogen Haemophilus influenzae grown in the presence of sialic acid. A combination of molecular genetics, MS and NMR spectroscopy techniques showed that this structural unit extended from the proximal heptose residue of the inner core region of the LPS molecule. The structure of the Sial-lNnT unit was identical to that found in meningococcal LPS, but glycoforms containing truncations of the Sial-lNnT unit, comprising fewer residues than the complete oligosaccharide component, were not detected. The finding of sialylated glycoforms that were either fully extended or absent suggests a novel biosynthetic feature for adding the terminal tetrasaccharide unit of the Sial-lNnT to the glycose acceptor at the proximal inner core heptose.

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

    Science.gov (United States)

    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.

  4. Hurricane related flooding monitoring: a method to delineate potentially affected areas by using a GIS model in the Caribbean area

    Science.gov (United States)

    Melelli, L.; Taramelli, A.; Sorichetta, A.; Pasqui, M.

    2007-12-01

    This research integrates the concept that the subject of natural hazards and the use of existing remote sensing systems in the different phases of a disaster management for a specific hurricane hazard, is based on the applicability of GIS model for increasing preparedness and providing early warning. The modelling of an hurricane event in potentially affected areas by GIS has recently become a major topic of research. In this context the disastrous effects of hurricanes on coastal communities and surroundings areas are well known, but there is a need to better understand the causes and the hazards contributions of the different events related to an hurricane, like storm surge, flooding and high winds. This blend formed the basis of a semi- quantitative and promising approach in order to model the spatial distribution of the final hazard along the affected areas. The applied model determines a sudden onset zoning from a set of available parameters starting from topography based on Shuttle Radar Topography Mission (SRTM) data. From the Digital Elevation Model as a first step the river network is derived and then classified based on the Strahler order account as proportional to flooding area. Then we use a hydrologic model that uses the wetness index (a parameter of specific catchment area defined as upslope area per unit contour length) to better quantify the drainage area that contributes to the flooded events. Complementary data for the final model includes remote sensed density rain dataset for the hurricane events taking into account and existing hurricane tracks inventories together with hurricane structure model (different buffers related to wind speed hurricane parameters in a GIS environment). To assess the overall susceptibility, the hazard results were overlaid with population dataset and landcover. The approach, which made use of a number of available global data sets, was then validated on a regional basis using past experience on hurricane frequency

  5. THE IMPACT OF HURRICANE BETA ON THE FORESTS OF PROVIDENCIA ISLAND, COLOMBIA, SOUTHWEST CARIBBEAN

    Directory of Open Access Journals (Sweden)

    Ruiz Jorge

    2010-12-01

    Full Text Available One of the consequences of global warming in the Caribbean is an increase in thefrequency and intensity of hurricanes. Little is known on the impact of this naturalphenomenon on forests, particularly for dry tropical forests. Understanding this impactin terms of structure and species richness is important for forest management. Slowmoving Hurricane Beta, a category 1, struck Old Providence island, Colombia, inOctober 29, 2005. Before Beta woody vegetation was characterized by 88 2 x 50 mplots (0.01 ha established throughout the island following the protocol by Gentry(1982; 59 plots were studied fi ve years earlier and 29 plots four to fi ve monthsearlier. The impact of hurricane Beta was assessed within 11 plots located in the DryTropical Forests of Old Providence, six months after the hurricane. The These plotswere measured in species composition, diameter at breast height (DBH, and heightwere measured within these plots. There was a considerable reduction in the numberof individuals, stems, height, basal areas, and there was no signifi cant differencebetween DBH. Height damage was positively associated with increasing DHB class.Furthermore, based on the results of species richness, even after controlling for thedifferent number of individuals, through rarefaction, there was no major differencebefore and after Beta.

  6. 78 FR 32296 - Second Allocation of Public Transportation Emergency Relief Funds in Response to Hurricane Sandy...

    Science.gov (United States)

    2013-05-29

    ... Response to Hurricane Sandy: Response, Recovery & Resiliency AGENCY: Federal Transit Administration (FTA... recipients most severely affected by Hurricane Sandy: the Metropolitan Transportation Authority, New Jersey... Federal Register notice, bringing the total amount of Hurricane Sandy Emergency Relief funds allocated...

  7. Effect of severe hurricanes on Biorock Coral Reef Restoration Projects in Grand Turk, Turks and Caicos Islands

    Directory of Open Access Journals (Sweden)

    Lucy Wells

    2010-10-01

    Full Text Available Artificial reefs are often discouraged in shallow waters over concerns of storm damage to structures and surrounding habitat. Biorock coral reef restoration projects were initiated in waters around 5m deep in Grand Turk, at Oasis (October 2006 and at Governor’s Beach (November 2007. Hemi-cylindrical steel modules, 6m long were used, four modules at Oasis and six at Governor’s Beach. Each project has over 1200 corals transplanted from sites with high sedimentation damage, and are regularly monitored for coral growth, mortality and fish populations. Corals show immediate growth over wires used to attach corals. Growth has been measured from photographs using a software program and is faster at Governor’s Beach. After hurricanes Hanna and Ike (September 2008 the Governor’s Beach structure was fully standing since the waves passed straight through with little damage, the Oasis structures which were tie-wired rather than welded had one module collapse (since been replaced with a new, welded structure. Hurricane Ike was the strongest hurricane on record to hit Grand Turk. Most cables were replaced following the hurricanes due to damage from debris and high wave action. The projects lost about a third of the corals due to hurricanes. Most of those lost had only been wired a few days before and had not yet attached themselves firmly. These projects have regenerated corals and fish populations in areas of barren sand or bedrock and are now attractive to snorkelers. High coral survival and low structural damage after hurricanes indicate that Biorock reef restoration can be effective in storm-impacted areas. Rev. Biol. Trop. 58 (Suppl. 3: 141-149. Epub 2010 October 01.

  8. Effect of severe hurricanes on biorock coral reef restoration projects in Grand Turk, Turks and Caicos Islands.

    Science.gov (United States)

    Wells, Lucy; Perez, Fernando; Hibbert, Marlon; Clerveaux, Luc; Johnson, Jodi; Goreau, Thomas J

    2010-10-01

    Artificial reefs are often discouraged in shallow waters over concerns of storm damage to structures and surrounding habitat. Biorock coral reef restoration projects were initiated in waters around 5 m deep in Grand Turk, at Oasis (October 2006) and at Governor's Beach (November 2007). Hemi-cylindrical steel modules, 6m long were used, four modules at Oasis and six at Governor's Beach. Each project has over 1200 corals transplanted from sites with high sedimentation damage, and are regularly monitored for coral growth, mortality and fish populations. Corals show immediate growth over wires used to attach corals. Growth has been measured from photographs using a software program and is faster at Governor's Beach. After hurricanes Hanna and Ike (September 2008) the Governor's Beach structure was fully standing since the waves passed straight through with little damage, the Oasis structures which were tie-wired rather than welded had one module collapse (since been replaced with a new, welded structure). Hurricane Ike was the strongest hurricane on record to hit Grand Turk. Most cables were replaced following the hurricanes due to damage from debris and high wave action. The projects lost about a third of the corals due to hurricanes. Most of those lost had only been wired a few days before and had not yet attached themselves firmly. These projects have regenerated corals and fish populations in areas of barren sand or bedrock and are now attractive to snorkelers. High coral survival and low structural damage after hurricanes indicate that Biorock reef restoration can be effective in storm-impacted areas.

  9. Rediscovering community--reflections after Hurricane Sandy.

    Science.gov (United States)

    See, Sharon

    2013-01-01

    Hoboken, New Jersey, is a town of 50,000 residents located across the Hudson River from New York City. Most of Hoboken's infrastructure was compromised during Hurricane Sandy as a result of flooding and power outages that rendered many businesses inoperable, including all of the pharmacies in town. Despite a focus on emergency preparedness since Hurricane Katrina and 9/11, there were no contingencies in place to facilitate and assess the medication needs of the community in the event of a natural disaster. This essay describes how the author rediscovered the meaning of community, and through working with colleagues in other health care disciplines and non-health care volunteers, provided care to patients in suboptimal circumstances.

  10. Lagrangian mixing in an axisymmetric hurricane model

    Directory of Open Access Journals (Sweden)

    B. Rutherford

    2009-09-01

    Full Text Available This paper discusses the extension of established Lagrangian mixing measures to make them applicable to data extracted from a 2-D axisymmetric hurricane simulation. Because of the non-steady and unbounded characteristics of the simulation, the previous measures are extended to a moving frame approach to create time-dependent mixing rates that are dependent upon the initial time of particle integration, and are computed for nonlocal regions. The global measures of mixing derived from finite-time Lyapunov exponents, relative dispersion, and a measured mixing rate are applied to distinct regions representing different characteristic feautures within the model. It is shown that these time-dependent mixing rates exhibit correlations with maximal tangential winds during a quasi-steady state, establishing a connection between mixing and hurricane intensity.

  11. The thermodynamic evolution of the hurricane boundary layer during eyewall replacement cycles

    Science.gov (United States)

    Williams, Gabriel J.

    2016-12-01

    Eyewall replacement cycles (ERCs) are frequently observed during the lifecycle of mature tropical cyclones. Although the kinematic structure and intensity changes during an ERC have been well-documented, comparatively little research has been done to examine the evolution of the tropical cyclone boundary layer (TCBL) during an ERC. This study will examine how the inner core thermal structure of the TCBL is affected by the presence of multiple concentric eyewalls using a high-resolution moist, hydrostatic, multilayer diagnostic boundary layer model. Within the concentric eyewalls above the cloud base, latent heat release and vertical advection (due to the eyewall updrafts) dominate the heat and moisture budgets, whereas vertical advection (due to subsidence) and vertical diffusion dominate the heat and moisture budgets for the moat region. Furthermore, it is shown that the development of a moat region within the TCBL depends sensitively on the moat width in the overlying atmosphere and the relative strength of the gradient wind field in the overlying atmosphere. These results further indicate that the TCBL contributes to outer eyewall formation through a positive feedback process between the vorticity in the nascent outer eyewall, boundary layer convergence, and boundary layer moist convection.

  12. Atlantic hurricane surge response to geoengineering

    Energy Technology Data Exchange (ETDEWEB)

    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.

  13. Atlantic hurricane surge response to geoengineering.

    Science.gov (United States)

    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.

  14. Complicated grief associated with hurricane Katrina.

    Science.gov (United States)

    Shear, M Katherine; McLaughlin, Katie A; Ghesquiere, Angela; Gruber, Michael J; Sampson, Nancy A; Kessler, Ronald C

    2011-08-01

    Although losses are important consequences of disasters, few epidemiological studies of disasters have assessed complicated grief (CG) and none assessed CG associated with losses other than death of loved one. Data come from the baseline survey of the Hurricane Katrina Community Advisory Group, a representative sample of 3,088 residents of the areas directly affected by Hurricane Katrina. A brief screen for CG was included containing four items consistent with the proposed DSM-V criteria for a diagnosis of bereavement-related adjustment disorder. Fifty-eight and half percent of respondents reported a significant hurricane-related loss: Most-severe losses were 29.0% tangible, 9.5% interpersonal, 8.1% intangible, 4.2% work/financial, and 3.7% death of loved one. Twenty-six point one percent respondents with significant loss had possible CG and 7.0% moderate-to-severe CG. Death of loved one was associated with the highest conditional probability of moderate-to-severe CG (18.5%, compared to 1.1-10.5% conditional probabilities for other losses), but accounted for only 16.5% of moderate-to-severe CG due to its comparatively low prevalence. Most moderate-to-severe CG was due to tangible (52.9%) or interpersonal (24.0%) losses. Significant predictors of CG were mostly unique to either bereavement (racial-ethnic minority status, social support) or other losses (prehurricane history of psychopathology, social competence.). Nonbereavement losses accounted for the vast majority of hurricane-related possible CG despite risk of CG being much higher in response to bereavement than to other losses. This result argues for expansion of research on CG beyond bereavement and alerts clinicians to the need to address postdisaster grief associated with a wide range of losses. © 2011 Wiley-Liss, Inc.

  15. Hurricane Katrina as a "teachable moment"

    Science.gov (United States)

    Glantz, M. H.

    2008-04-01

    By American standards, New Orleans is a very old, very popular city in the southern part of the United States. It is located in Louisiana at the mouth of the Mississippi River, a river which drains about 40% of the Continental United States, making New Orleans a major port city. It is also located in an area of major oil reserves onshore, as well as offshore, in the Gulf of Mexico. Most people know New Orleans as a tourist hotspot; especially well-known is the Mardi Gras season at the beginning of Lent. People refer to the city as the "Big Easy". A recent biography of the city refers to it as the place where the emergence of modern tourism began. A multicultural city with a heavy French influence, it was part of the Louisiana Purchase from France in early 1803, when the United States bought it, doubling the size of the United States at that time. Today, in the year 2007, New Orleans is now known for the devastating impacts it withstood during the onslaught of Hurricane Katrina in late August 2005. Eighty percent of the city was submerged under flood waters. Almost two years have passed, and many individuals and government agencies are still coping with the hurricane's consequences. And insurance companies have been withdrawing their coverage for the region. The 2005 hurricane season set a record, in the sense that there were 28 named storms that calendar year. For the first time in hurricane forecast history, hurricane forecasters had to resort to the use of Greek letters to name tropical storms in the Atlantic and Gulf (Fig.~1). Hurricane Katrina was a Category 5 hurricane when it was in the middle of the Gulf of Mexico, after having passed across southern Florida. At landfall, Katrina's winds decreased in speed and it was relabeled as a Category 4. It devolved into a Category 3 hurricane as it passed inland when it did most of its damage. Large expanses of the city were inundated, many parts under water on the order of 20 feet or so. The Ninth Ward, heavily

  16. Coastal Change During Hurricane Isabel 2003

    Science.gov (United States)

    Morgan, Karen

    2009-01-01

    On September 18, 2003, Hurricane Isabel made landfall on the northern Outer Banks of North Carolina. At the U.S. Army Corps of Engineer's Field Research Facility in Duck, 125 km north of where the eyewall cut across Hatteras Island, the Category 2 storm generated record conditions for the 27 years of monitoring. The storm produced an 8.1 m high wave measured at a waverider buoy in 20 m of water and a 1.5 m storm surge. As part of a program to document and better understand the changes in vulnerability of the Nation's coasts to extreme storms, the U.S. Geological Survey (USGS), in collaboration with the National Aeronautics and Space Administration (NASA), surveyed the impact zone of Hurricane Isabel. Methods included pre- and post-storm photography, videography, and lidar. Hurricane Isabel caused extensive erosion and overwash along the Outer Banks near Cape Hatteras, including the destruction of houses, the erosion of protective sand dunes, and the creation of island breaches. The storm eroded beaches and dunes in Frisco and Hatteras Village, southwest of the Cape. Overwash deposits covered roads and filled homes with sand. The most extensive beach changes were associated with the opening of a new breach about 500 m wide that divided into three separate channels that completely severed the island southwest of Cape Hatteras. The main breach, and a smaller one several kilometers to the south (not shown), occurred at minima in both island elevation and island width.

  17. Hurricane Katrina as a "teachable moment"

    Directory of Open Access Journals (Sweden)

    M. H. Glantz

    2008-04-01

    Full Text Available By American standards, New Orleans is a very old, very popular city in the southern part of the United States. It is located in Louisiana at the mouth of the Mississippi River, a river which drains about 40% of the Continental United States, making New Orleans a major port city. It is also located in an area of major oil reserves onshore, as well as offshore, in the Gulf of Mexico. Most people know New Orleans as a tourist hotspot; especially well-known is the Mardi Gras season at the beginning of Lent. People refer to the city as the "Big Easy". A recent biography of the city refers to it as the place where the emergence of modern tourism began. A multicultural city with a heavy French influence, it was part of the Louisiana Purchase from France in early 1803, when the United States bought it, doubling the size of the United States at that time.

    Today, in the year 2007, New Orleans is now known for the devastating impacts it withstood during the onslaught of Hurricane Katrina in late August 2005. Eighty percent of the city was submerged under flood waters. Almost two years have passed, and many individuals and government agencies are still coping with the hurricane's consequences. And insurance companies have been withdrawing their coverage for the region.

    The 2005 hurricane season set a record, in the sense that there were 28 named storms that calendar year. For the first time in hurricane forecast history, hurricane forecasters had to resort to the use of Greek letters to name tropical storms in the Atlantic and Gulf (Fig.~1.

    Hurricane Katrina was a Category 5 hurricane when it was in the middle of the Gulf of Mexico, after having passed across southern Florida. At landfall, Katrina's winds decreased in speed and it was relabeled as a Category 4. It devolved into a Category 3 hurricane as it passed inland when it did most of its damage. Large expanses of the city were inundated, many parts under water on

  18. National assessment of hurricane-induced coastal erosion hazards: Southeast Atlantic Coast

    Science.gov (United States)

    Stockdon, Hilary F.; Doran, Kara S.; Thompson, David M.; Sopkin, Kristin L.; Plant, Nathaniel G.

    2013-01-01

    Beaches serve as a natural barrier between the ocean and inland communities, ecosystems, and natural resources. However, these dynamic environments move and change in response to winds, waves, and currents. During extreme storms, changes to beaches can be large, and the results are sometimes catastrophic. Lives may be lost, communities destroyed, and millions of dollars spent on rebuilding. During storms, large waves may erode beaches, and high storm surge shifts the erosive force of the waves higher on the beach. In some cases, the combined effects of waves and surge may cause overwash or flooding. Building and infrastructure on or near a dune can be undermined during wave attack and subsequent erosion. During Hurricane Ivan in 2004, a five-story condominium in Orange Beach, Alabama, collapsed after the sand dune supporting the foundation eroded. The September 1999 landfall of Hurricane Dennis caused erosion and undermining that destroyed roads, foundations, and septic systems. Waves overtopping a dune can transport sand inland, covering roads and blocking evacuation routes or emergency relief. If storm surge inundates barrier island dunes, currents flowing across the island can create a breach, or new inlet, completely severing evacuation routes. Waves and surge during the 2003 landfall of Hurricane Isabel left a 200-meter (m) wide breach that cut the only road to and from the village of Hatteras, N.C. Extreme coastal changes caused by hurricanes may increase the vulnerability of communities both during a storm and to future storms. For example, when sand dunes on a barrier island are eroded substantially, inland structures are exposed to storm surge and waves. Absent or low dunes also allow water to flow inland across the island, potentially increasing storm surge in the back bay, on the soundside of the barrier, and on the mainland. During Hurricane Isabel the protective sand dunes near the breach were completely eroded, increasing vulnerability to future

  19. Studies on structural stability of thermophilic Sulfolobus acidocaldarius ribosomes.

    Science.gov (United States)

    Yangala, Kalavathi; Suryanarayana, Tangirala

    2007-02-01

    Structural stability of thermophilic archaeon Sulfolobus acidocaldarius ribosomes, with respect their susceptibility to pancreatic RNase A and stability to temperature (deltaTm), on treatment with various stabilizing (polyamines) and destabilizing (sulfhydryl and intercalating) agents were studied and compared with mesophilic E. coli ribosomes, to understand the structural differences between thermophilic and mesophilic ribosomes. Thermophilic archaeal ribosomes and their subunits were 10-times less susceptible to pancreatic RNase A, compared to mesophilic ribosomes, showing the presence of strong and compact structural organization in them. Thermophilic ribosomes treated with destabilizing agents, such as sulfhydryl reagents [5,5'-Dithio-bis-(2-nitrobenzoic acid), N-ethylmaleimide and p-hydroxymercurybenzoate) and intercalating agents (ethidium bromide, EtBr) showed higher stability to RNase A, compared to similarly treated mesophilic ribosomes, indicating the unavailability of thiol-reactive groups and the presence of strong solvent inaccessible inner core. Higher stability of thermophilic ribosomes compared to mesophilic ribosomes to unfolding agents like urea further supported the presence of strong inner core particle. Thermophilic ribosomes treated with intercalating agents, such as EtBr were less susceptible to RNase A, though they bound to more reagent, showing the rigidity or resilience of their macromolecular structure to alterations caused by destabilizing agents. Overall, these results indicated that factors such as presence of strong solvent inaccessible inner core and rigidity of ribosome macromolecular structure contributed stability of thermophilic ribosomes to RNase A and other destabilizing agents, when compared to mesophilic ribosomes.

  20. Nova Scotia Power response to Hurricane Juan

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-10-01

    Hurricane Juan hit the Halifax Regional Municipality on September 28, 2003, creating the largest outage in Nova Scotia Power's history. This detailed report documents the extensive damage that Hurricane Juan caused to the power transmission and distribution system in Nova Scotia. It also reviews the massive power restoration effort, with reference to numerous interviews, computer records and data logs which offer a wide range of observations, statistics and insights into the preparation and performance of Nova Scotia Power Inc. (NSPI) and the efforts of other key organizations following the storm. NSPI organized a recovery effort that matched the intensity of the hurricane. A fire in the Scotia Square Office Tower caused the evacuation of the company's call centre. The Tufts Cove station in Dartmouth, which generates 400 megawatts of power, was forced to shut down. Excess electricity was moved into New Brunswick and other jurisdictions to maintain system stability. The main priority was to restore customers back to service. Within 5 days of the hurricane, 95 per cent of those who lost power had service restored. Hurricane Juan caused the most damage to the transmission and distribution system in NSPI's history. Three out of five high capacity transmission lines were put out of service. Three 120-foot high transmission towers fell, and 17 main transmission lines were damaged and put out of service. Forty-five major substations were affected and 145 distribution feeders were damaged or tripped off, including 106 in the Halifax Regional Municipality. Large portions of 4,500 kilometres of local distribution lines in the Halifax Regional Municipality were damaged, including thousands of kilometers across the Northeast. The power crew, consisting of 2,000 individuals from the region and neighbouring utilities in New Brunswick and Maine, worked for 15 consecutive days to replace 275 transformers, 760 power poles, and 125,000 metres of conductor wire. NSPI

  1. A Numerical Study of the Effect of GOES Sounder Cloud-Cleared Brightness Temperatures on the Prediction of Hurricane Felix.

    Science.gov (United States)

    Zou, Xiaolei; Xiao, Qingnong; Lipton, Alan E.; Modica, George D.

    2001-01-01

    The influence of Geostationary Operational Environmental Satellite (GOES) brightness temperature data on the numerical simulations of Hurricane Felix is investigated. Satellite data are included as an augmentation to a bogus data assimilation (BDA) procedure using a mesoscale adjoint modeling system. The assimilation of satellite data modified not only the environmental flow but also the structure of the initial vortex, which is located over a region devoid of satellite data. This modification resulted in a reduction of the 12-h forecast errors verified by radiosonde data. Despite the fact that the forecast using only the bogus surface low at the initial time was very good, track and intensity forecasts beyond 2 days of model integration were shown to be improved further by including satellite data in the initialization procedure. Differences in the prediction of Hurricane Felix with and without satellite data were also found in the prediction of the upper-level jet, the cold temperature trough ahead of the hurricane, the size of the hurricane eye, and the location of the maximum hydrometeor. Although the focus of this study is to assess the effect of the direct use of satellite brightness temperature data on hurricane prediction, it is also noted that the BDA experiment including only the bogus data shows a positive effect of the BDA vortex on the environmental flow during the forecast period, as verified by satellite observations.

  2. The effect of Hurricane Katrina on nekton communities in the tidal freshwater marshes of Breton Sound, Louisiana, USA

    Science.gov (United States)

    Piazza, Bryan P.; La Peyre, M.K.

    2009-01-01

    Hurricanes are climatically-induced resource pulses that affect community structure through the combination of physical and chemical habitat change. Estuaries are susceptible to hurricane pulses and are thought to be resilient to habitat change, because biotic communities often return quickly to pre-hurricane conditions. Although several examples provide evidence of quick recovery of estuarine nekton communities following a hurricane, few studies take place in tidal freshwater habitat where physical habitat effects can be extensive and may not be readily mitigated. We examined nekton communities (density, biomass, ?? and ?? diversity, % occurrence by residence status) in tidal freshwater marshes in Breton Sound, Louisiana, before and after a direct hit by Hurricane Katrina (2005). Vegetative marsh loss in the study area was extensive, and elevated salinity persisted for almost 6 months. Post-Katrina nekton density and biomass increased significantly, and the nekton community shifted from one of tidal freshwater/resident species to one containing brackish/migrant species, many of which are characterized by pelagic and benthic life history strategies. By spring 2007, the nekton community had shifted back to tidal freshwater/resident species, despite the enduring loss of vegetated marsh habitat. ?? 2009 Elsevier Ltd.

  3. Surveillance for illness and injury after hurricane Katrina--New Orleans, Louisiana, September 8-25, 2005.

    Science.gov (United States)

    2005-10-14

    Hurricane Katrina struck the Gulf Coast on August 29, 2005, resulting in extensive structural damage and severe flooding from breached levees in and around New Orleans, Louisiana. The public health infrastructure of the Louisiana Department of Health and Hospitals (LDHH) was damaged extensively, limiting surveillance for illnesses, injuries, and toxic exposures. On September 9, 2005, LDHH, CDC, and functioning emergency treatment resources (i.e., hospitals, disaster medical assistance teams, and military aid stations) established an active surveillance system to detect outbreaks of disease and characterize post-hurricane injuries and illnesses. As of September 25, the system had monitored 7,508 reports of health-related events at participating facilities. Trends observed in the data prompted investigations of respiratory and rash illnesses, but no major outbreaks of disease or hazardous environmental exposures were detected. These data also were used to identify post-hurricane injury patterns and to guide prevention messages to residents and relief workers. A natural disaster of the magnitude of Hurricane Katrina requires a sustained response and a detailed plan for return to pre-hurricane surveillance activities.

  4. The effect of Hurricane Katrina on nekton communities in the tidal freshwater marshes of Breton Sound, Louisiana, USA

    Science.gov (United States)

    Piazza, Bryan P.; La Peyre, Megan K.

    2009-06-01

    Hurricanes are climatically-induced resource pulses that affect community structure through the combination of physical and chemical habitat change. Estuaries are susceptible to hurricane pulses and are thought to be resilient to habitat change, because biotic communities often return quickly to pre-hurricane conditions. Although several examples provide evidence of quick recovery of estuarine nekton communities following a hurricane, few studies take place in tidal freshwater habitat where physical habitat effects can be extensive and may not be readily mitigated. We examined nekton communities (density, biomass, α and β diversity, % occurrence by residence status) in tidal freshwater marshes in Breton Sound, Louisiana, before and after a direct hit by Hurricane Katrina (2005). Vegetative marsh loss in the study area was extensive, and elevated salinity persisted for almost 6 months. Post-Katrina nekton density and biomass increased significantly, and the nekton community shifted from one of tidal freshwater/resident species to one containing brackish/migrant species, many of which are characterized by pelagic and benthic life history strategies. By spring 2007, the nekton community had shifted back to tidal freshwater/resident species, despite the enduring loss of vegetated marsh habitat.

  5. Baseline Design of a Hurricane-Resilient Wind Turbine (Poster)

    Energy Technology Data Exchange (ETDEWEB)

    Damiani, R.; Robertson, A.; Schreck, S.; Maples, B.; Anderson, M.; Finucane, Z.; Raina, A.

    2014-10-01

    Under U.S. Department of Energy-sponsored research FOA 415, the National Renewable Energy Laboratory led a team of research groups to produce a complete design of a large wind turbine system to be deployable in the western Gulf of Mexico region. As such, the turbine and its support structure would be subjected to hurricane-loading conditions. Among the goals of this research was the exploration of advanced and innovative configurations that would help decrease the levelized cost of energy (LCOE) of the design, and the expansion of the basic IEC design load cases (DLCs) to include hurricane environmental conditions. The wind turbine chosen was a three-bladed, downwind, direct-drive, 10-MW rated machine. The rotor blade was optimized based on an IEC load suite analysis. The drivetrain and nacelle components were scaled up from a smaller sized turbine using industry best practices. The tubular steel tower was sized using ultimate load values derived from the rotor optimization analysis. The substructure is an innovative battered and raked jacket structure. The innovative turbine has also been modeled within an aero-servo-hydro-elastic tool, and future papers will discuss results of the dynamic response analysis for select DLCs. Although multiple design iterations could not be performed because of limited resources in this study, and are left to future research, the obtained data will offer a good indication of the expected LCOE for large offshore wind turbines to be deployed in subtropical U.S. waters, and the impact design innovations can have on this value.

  6. Differences in regeneration between hurricane damaged and clear-cut mangrove stands 25 years after clearing

    OpenAIRE

    Ferwerda, J.G.; Ketner, P.; McGuiness, K.A.

    2007-01-01

    The effect of human disturbance on mangrove forest may be substantially different from the effects of natural disturbances. This paper describes differences in vegetation composition and structure of five vegetation types in two mangrove areas near Darwin, Australia, 25 years after disturbance. The vegetation in clear-felled forest showed more adult Avicennia marina than in the hurricane-affected forest, and a virtual absence of A. marina juveniles and saplings. This indicates that A. marina ...

  7. Mediating the Morals of Disasters: Hurricane Katrina in Norwegian News Media

    OpenAIRE

    Kyrre Kverndokk

    2014-01-01

    The Norwegian media responses to Hurricane Katrina were structured around three well-established sets of motifs in a globalized late modern disaster discourse: 1) The collapse of civil society, 2) Social vulnerability 2) Extreme weather and global warming. These sets of motifs portray relationships or non-relationships between natural evil and moral evil. Starting with Voltaire’s description of Candide’s arrival in Lisbon after the earthquake I discuss how an 18th century disaster discourse i...

  8. Avifauna response to hurricanes: regional changes in community similarity

    Science.gov (United States)

    Chadwick D. Rittenhouse; Anna M. Pidgeon; Thomas P. Albright; Patrick D. Culbert; Murray K. Clayton; Curtis H. Flather; Chengquan Huang; Jeffrey G. Masek; Volker C. Radeloff

    2010-01-01

    Global climate models predict increases in the frequency and intensity of extreme climatic events such as hurricanes, which may abruptly alter ecological processes in forests and thus affect avian diversity. Developing appropriate conservation measures necessitates identifying patterns of avifauna response to hurricanes. We sought to answer two questions: (1) does...

  9. Long-term response of Caribbean palm forests to hurricanes

    Science.gov (United States)

    Ariel Lugo; J.L. Frangi

    2016-01-01

    We studied the response of Prestoea montana (Sierra Palm, hereafter Palm) brakes and a Palm floodplain forest to hurricanes in the Luquillo Experimental Forest in Puerto Rico. Over a span of 78 years, 3 hurricanes passed over the study sites for which we have 64 years of measurements for Palm brakes and 20 years for the Palm floodplain forest. For each stand, species...

  10. Resilience of Professional Counselors Following Hurricanes Katrina and Rita

    Science.gov (United States)

    Lambert, Simone F.; Lawson, Gerard

    2013-01-01

    Professional counselors who provided services to those affected by Hurricanes Katrina and Rita completed the K6+ (screen for severe mental illness), the Posttraumatic Growth Inventory, and the Professional Quality of Life Scale. Results indicated that participants who survived the hurricanes had higher levels of posttraumatic growth than…

  11. The Business of Intimacy: Hurricanes and Howling Wolves

    Science.gov (United States)

    Paley, Vivian

    2006-01-01

    The date is September 9, 2005. This article is set in a rural Wisconsin community, a thousand miles north of New Orleans, where Hurricane Katrina is about to make landfall. The four- and five- year- olds in Mrs. Olson's classroom have never experienced a hurricane or seen flood waters rise to cover the farms and houses they know, but they cannot…

  12. Resilience of Professional Counselors Following Hurricanes Katrina and Rita

    Science.gov (United States)

    Lambert, Simone F.; Lawson, Gerard

    2013-01-01

    Professional counselors who provided services to those affected by Hurricanes Katrina and Rita completed the K6+ (screen for severe mental illness), the Posttraumatic Growth Inventory, and the Professional Quality of Life Scale. Results indicated that participants who survived the hurricanes had higher levels of posttraumatic growth than…

  13. Teacher Guidelines for Helping Students after a Hurricane

    Science.gov (United States)

    National Child Traumatic Stress Network, 2013

    2013-01-01

    Being in a hurricane can be very frightening, and the days, weeks, and months following the storm can be very stressful. Most families recover over time, especially with the support of relatives, friends, and their community. But different families may have different experiences during and after a hurricane, and how long it takes them to recover…

  14. Post-hurricane forest damage assessment using satellite remote sensing

    Science.gov (United States)

    W. Wang; J.J. Qu; X. Hao; Y. Liu; J.A. Stanturf

    2010-01-01

    This study developed a rapid assessment algorithm for post-hurricane forest damage estimation using moderate resolution imaging spectroradiometer (MODIS) measurements. The performance of five commonly used vegetation indices as post-hurricane forest damage indicators was investigated through statistical analysis. The Normalized Difference Infrared Index (NDII) was...

  15. Mass Media Use by College Students during Hurricane Threat

    Science.gov (United States)

    Piotrowski, Chris

    2015-01-01

    There is a dearth of studies on how college students prepare for the threat of natural disasters. This study surveyed college students' preferences in mass media use prior to an approaching hurricane. The convenience sample (n = 76) were from a university located in the hurricane-prone area of the central Gulf of Mexico coast. Interestingly,…

  16. Experience of Hurricane Katrina and Reported Intimate Partner Violence

    Science.gov (United States)

    Harville, Emily W.; Taylor, Catherine A.; Tesfai, Helen; Xiong, Xu; Buekens, Pierre

    2011-01-01

    Intimate partner violence (IPV) has been associated with stress, but few studies have examined the effect of natural disaster on IPV. In this study, the authors examine the relationship between experience of Hurricane Katrina and reported relationship aggression and violence in a cohort of 123 postpartum women. Hurricane experience is measured…

  17. Retention of Displaced Students after Hurricanes Katrina and Rita

    Science.gov (United States)

    Coco, Joshua Christian

    2017-01-01

    The purpose of the study was to investigate the strategies that university leaders implemented to improve retention of displaced students in the aftermaths of Hurricanes Katrina and Rita. The universities that participated in this study admitted displaced students after Hurricanes Katrina and Rita. This study utilized a qualitative…

  18. Physical aspects of Hurricane Hugo in Puerto Rico

    Science.gov (United States)

    Scatena, F.N.; Larsen, Matthew C.

    1991-01-01

    On 18 September 1989 the western part ofHurricane Hugo crossed eastern Puerto Rico and the Luquillo Experimental Forest (LEF). Storm-facing slopes on the northeastern part of the island that were within 15 km of the eye and received greater than 200 mm of rain were most affected by the storm. In the LEF and nearby area, recurrence intervals associated with Hurricane Hugo were 50 yr for wind velocity, 10 to 31 yr for stream discharge, and 5 yr for rainfall intensity. To compare the magnitudes of the six hurricanes to pass over PuertoRico since 1899, 3 indices were developed using the standardized values of the product of: the maximum sustained wind speed at San Juan squared and storm duration; the square of the product of the maximum sustained wind velocity at San Juan and the ratio of the distance between the hurricane eye and San Juan to the distance between the eye and percentage of average annual rainfall delivered by the storm. Based on these indices, HurricaneHugo was of moderate intensity. However, because of the path of Hurricane Hugo, only one of these six storms (the 1932 storm) caused more damage to the LEF than Hurricane Hugo. Hurricanes of Hugo's magnitude are estimated to pass over the LEF once every 50-60 yr, on average. 

  19. Teacher Guidelines for Helping Students after a Hurricane

    Science.gov (United States)

    National Child Traumatic Stress Network, 2013

    2013-01-01

    Being in a hurricane can be very frightening, and the days, weeks, and months following the storm can be very stressful. Most families recover over time, especially with the support of relatives, friends, and their community. But different families may have different experiences during and after a hurricane, and how long it takes them to recover…

  20. Experience of Hurricane Katrina and Reported Intimate Partner Violence

    Science.gov (United States)

    Harville, Emily W.; Taylor, Catherine A.; Tesfai, Helen; Xiong, Xu; Buekens, Pierre

    2011-01-01

    Intimate partner violence (IPV) has been associated with stress, but few studies have examined the effect of natural disaster on IPV. In this study, the authors examine the relationship between experience of Hurricane Katrina and reported relationship aggression and violence in a cohort of 123 postpartum women. Hurricane experience is measured…

  1. Predicting hurricane wind damage by claim payout based on Hurricane Ike in Texas

    Directory of Open Access Journals (Sweden)

    Ji-Myong Kim

    2016-09-01

    Full Text Available The increasing occurrence of natural disasters and their related damage have led to a growing demand for models that predict financial loss. Although considerable research on the financial losses related to natural disasters has found significant predictors, there has been a lack of comprehensive study that addresses the relationship among vulnerabilities, natural disasters, and the economic losses of individual buildings. This study identifies the vulnerability indicators for hurricanes to establish a metric to predict the related financial loss. We classify hurricane-prone areas by highlighting the spatial distribution of losses and vulnerabilities. This study used a Geographical Information System (GIS to combine and produce spatial data and a multiple regression method to establish a wind damage prediction model. As the dependent variable, we used the value of the Texas Windstorm Insurance Association (TWIA claim payout divided by the appraised values of the buildings to predict real economic loss. As independent variables, we selected a hurricane indicator and built environment vulnerability indicators. The model we developed can be used by government agencies and insurance companies to predict hurricane wind damage.

  2. On the Impact Angle of Hurricane Sandy's New Jersey Landfall

    Science.gov (United States)

    Hall, Timothy M.; Sobel, Adam H.

    2013-01-01

    Hurricane Sandy's track crossed the New Jersey coastline at an angle closer to perpendicular than any previous hurricane in the historic record, one of the factors contributing to recordsetting peak-water levels in parts of New Jersey and New York. To estimate the occurrence rate of Sandy-like tracks, we use a stochastic model built on historical hurricane data from the entire North Atlantic to generate a large sample of synthetic hurricanes. From this synthetic set we calculate that under long-term average climate conditions, a hurricane of Sandy's intensity or greater (category 1+) makes NJ landfall at an angle at least as close to perpendicular as Sandy's at an average annual rate of 0.0014 yr-1 (95% confidence range 0.0007 to 0.0023); i.e., a return period of 714 years (95% confidence range 435 to 1429).

  3. Hurricane Sandy: Shared Trauma and Therapist Self-Disclosure.

    Science.gov (United States)

    Rao, Nyapati; Mehra, Ashwin

    2015-01-01

    Hurricane Sandy was one of the most devastating storms to hit the United States in history. The impact of the hurricane included power outages, flooding in the New York City subway system and East River tunnels, disrupted communications, acute shortages of gasoline and food, and a death toll of 113 people. In addition, thousands of residences and businesses in New Jersey and New York were destroyed. This article chronicles the first author's personal and professional experiences as a survivor of the hurricane, more specifically in the dual roles of provider and trauma victim, involving informed self-disclosure with a patient who was also a victim of the hurricane. The general analytic framework of therapy is evaluated in the context of the shared trauma faced by patient and provider alike in the face of the hurricane, leading to important implications for future work on resilience and recovery for both the therapist and patient.

  4. Lipopolysaccharides from Serratia marcescens possess one or two 4-amino-4-deoxy-L-arabinopyranose 1-phosphate residues in the lipid A and D-glycero-D-talo-oct-2-ulopyranosonic acid in the inner core region.

    Science.gov (United States)

    Vinogradov, Evgeny; Lindner, Buko; Seltmann, Guntram; Radziejewska-Lebrecht, Joanna; Holst, Otto

    2006-08-25

    The carbohydrate backbones of the core-lipid A region were characterized from the lipopolysaccharides (LPSs) of Serratia marcescens strains 111R (a rough mutant strain of serotype O29) and IFO 3735 (a smooth strain not serologically characterized but possessing the O-chain structure of serotype O19). The LPSs were degraded either by mild hydrazinolysis (de-O-acylation) and hot 4 M KOH (de-N-acylation), or by hydrolysis in 2 % aqueous acetic acid, or by deamination. Oligosaccharide phosphates were isolated by high-performance anion-exchange chromatography. Through the use of compositional analysis, electrospray ionization Fourier transform mass spectrometry, and 1H and 13C NMR spectroscopy applying various one- and two-dimensional experiments, we identified the structures of the carbohydrate backbones that contained D-glycero-D-talo-oct-2-ulopyranosonic acid and 4-amino-4-deoxy-L-arabinose 1-phosphate residues. We also identified some truncated structures for both strains. All sugars were D-configured pyranoses and alpha-linked, except where stated otherwise.

  5. Asymmetric oceanic response to a hurricane: Deep water observations during Hurricane Isaac

    Science.gov (United States)

    Spencer, Laura J.; DiMarco, Steven F.; Wang, Zhankun; Kuehl, Joseph J.; Brooks, David A.

    2016-10-01

    The eye of Hurricane Isaac passed through the center of an array of six deep water water-column current meter moorings deployed in the northern Gulf of Mexico. The trajectory of the hurricane provided for a unique opportunity to quantify differences in the full water-column oceanic response to a hurricane to the left and right of the hurricane trajectory. Prior to the storm passage, relative vorticity on the right side of the hurricane was strongly negative, while on the left, relative vorticity was positive. This resulted in an asymmetry in the near-inertial frequencies oceanic response at depth and horizontally. A shift in the response to a slightly larger inertial frequencies ˜1.11f was observed and verified by theory. Additionally, the storm passage coincided with an asymmetric change in relative vorticity in the upper 1000 m, which persisted for ˜15 inertial periods. Vertical propagation of inertial energy was estimated at 29 m/d, while horizontal propagation at this frequency was approximately 5.7 km/d. Wavelet analysis showed two distinct subinertial responses, one with a period of 2-5 days and another with a period of 5-12 days. Analysis of the subinertial bands reveals that the spatial and temporal scales are shorter and less persistent than the near-inertial variance. As the array is geographically located near the site of the Deep Water Horizon oil spill, the spatial and temporal scales of response have significant implications for the fate, transport, and distribution of hydrocarbons following a deep water spill event.

  6. Shelf sediment transport during hurricanes Katrina and Rita

    Science.gov (United States)

    Xu, Kehui; Mickey, Rangley C.; Chen, Qin; Harris, Courtney K.; Hetland, Robert D.; Hu, Kelin; Wang, Jiaze

    2016-05-01

    Hurricanes can greatly modify the sedimentary record, but our coastal scientific community has rather limited capability to predict hurricane-induced sediment deposition. A three-dimensional sediment transport model was developed in the Regional Ocean Modeling System (ROMS) to study seabed erosion and deposition on the Louisiana shelf in response to Hurricanes Katrina and Rita in the year 2005. Sensitivity tests were performed on both erosional and depositional processes for a wide range of erosional rates and settling velocities, and uncertainty analysis was done on critical shear stresses using the polynomial chaos approximation method. A total of 22 model runs were performed in sensitivity and uncertainty tests. Estimated maximum erosional depths were sensitive to the inputs, but horizontal erosional patterns seemed to be controlled mainly by hurricane tracks, wave-current combined shear stresses, seabed grain sizes, and shelf bathymetry. During the passage of two hurricanes, local resuspension and deposition dominated the sediment transport mechanisms. Hurricane Katrina followed a shelf-perpendicular track before making landfall and its energy dissipated rapidly within about 48 h along the eastern Louisiana coast. In contrast, Hurricane Rita followed a more shelf-oblique track and disturbed the seabed extensively during its 84-h passage from the Alabama-Mississippi border to the Louisiana-Texas border. Conditions to either side of Hurricane Rita's storm track differed substantially, with the region to the east having stronger winds, taller waves and thus deeper erosions. This study indicated that major hurricanes can disturb the shelf at centimeter to meter levels. Each of these two hurricanes suspended seabed sediment mass that far exceeded the annual sediment inputs from the Mississippi and Atchafalaya Rivers, but the net transport from shelves to estuaries is yet to be determined. Future studies should focus on the modeling of sediment exchange between

  7. Gulf of Mexico hurricane wave simulations using SWAN: Bulk formula-based drag coefficient sensitivity for Hurricane Ike

    NARCIS (Netherlands)

    Huang, Y.; Weisberg, R.H.; Zheng, L.; Zijlema, M.

    2013-01-01

    The effects of wind input parameterizations on wave estimations under hurricane conditions are examined using the unstructured grid, third-generation wave model, Simulating WAves Nearshore (SWAN). Experiments using Hurricane Ike wind forcing, which impacted the Gulf of Mexico in 2008, illustrate tha

  8. Gulf of Mexico hurricane wave simulations using SWAN: Bulk formula-based drag coefficient sensitivity for Hurricane Ike

    NARCIS (Netherlands)

    Huang, Y.; Weisberg, R.H.; Zheng, L.; Zijlema, M.

    2013-01-01

    The effects of wind input parameterizations on wave estimations under hurricane conditions are examined using the unstructured grid, third-generation wave model, Simulating WAves Nearshore (SWAN). Experiments using Hurricane Ike wind forcing, which impacted the Gulf of Mexico in 2008, illustrate tha

  9. Gulf of Mexico hurricane wave simulations using SWAN: Bulk formula-based drag coefficient sensitivity for Hurricane Ike

    NARCIS (Netherlands)

    Huang, Y.; Weisberg, R.H.; Zheng, L.; Zijlema, M.

    2013-01-01

    The effects of wind input parameterizations on wave estimations under hurricane conditions are examined using the unstructured grid, third-generation wave model, Simulating WAves Nearshore (SWAN). Experiments using Hurricane Ike wind forcing, which impacted the Gulf of Mexico in 2008, illustrate

  10. The Hurricane Imaging Radiometer: Present and Future

    Science.gov (United States)

    Miller, Timothy L.; James, M. W.; Roberts, J. B.; Biswas, S. K.; Cecil, D.; Jones, W. L.; Johnson, J.; Farrar, S.; Sahawneh, S.; Ruf, C. S.; Morris, M.; Uhlhorn, E. W.; Black, P. G.

    2013-01-01

    The Hurricane Imaging Radiometer (HIRAD) is an airborne passive microwave radiometer designed to provide high resolution, wide swath imagery of surface wind speed in tropical cyclones from a low profile planar antenna with no mechanical scanning. Wind speed and rain rate images from HIRAD's first field campaign (GRIP, 2010) are presented here followed, by a discussion on the performance of the newly installed thermal control system during the 2012 HS3 campaign. The paper ends with a discussion on the next generation dual polarization HIRAD antenna (already designed) for a future system capable of measuring wind direction as well as wind speed.

  11. Insights into Tornadoes and Hurricanes from High-Resolution Numerical Simulations

    Science.gov (United States)

    Bryan, G. H.; Cione, J.; Dahl, N.; Kalina, E.; Lundquist, J. K.; Nolan, D. S.; Rotunno, R.; Stern, D. P.; Worsnop, R.

    2016-12-01

    Comprehensive measurements of wind speed in tornadoes and hurricanes are rare because these phenomena are infrequent, turbulent, and (of course) very hazardous. However, detailed knowledge of the distribution of winds would be useful for a variety of applications such as structural engineering, societal awareness, and weather forecasting. To help fill in gaps in this knowledge, numerical model simulations can play a crucial role. The NCAR Yellowstone supercomputer has been used to conduct idealized simulations of tornadoes and hurricanes with grid spacing as small as 1 m. The simulations provide insight into the maximum wind speeds that may be possible in nature and provide guidance for interpreting present-day and future observational platforms. To this end, we have built code into a numerical model to produce "mock" observational datasets from hypothetical airplanes, dropsondes, and instrumented towers. Results are currently being used to help design offshore wind turbines, evaluate tornado intercept strategies, and develop flight paths for unmanned aerial systems.

  12. Predicting Atlantic seasonal hurricane activity using outgoing longwave radiation over Africa

    Science.gov (United States)

    Karnauskas, Kristopher B.; Li, Laifang

    2016-07-01

    Seasonal hurricane activity is a function of the amount of initial disturbances (e.g., easterly waves) and the background environment in which they develop into tropical storms (i.e., the main development region). Focusing on the former, a set of indices based solely upon the meridional structure of satellite-derived outgoing longwave radiation (OLR) over the African continent are shown to be capable of predicting Atlantic seasonal hurricane activity with very high rates of success. Predictions of named storms based on the July OLR field and trained only on the time period prior to the year being predicted yield a success rate of 87%, compared to the success rate of NOAA's August outlooks of 53% over the same period and with the same average uncertainty range (±2). The resulting OLR indices are statistically robust, highly detectable, physically linked to the predictand, and may account for longer-term observed trends.

  13. Hurricane Sandy science plan: coastal impact assessments

    Science.gov (United States)

    Stronko, Jakob M.

    2013-01-01

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

  14. Estimating hurricane hazards using a GIS system

    Directory of Open Access Journals (Sweden)

    A. Taramelli

    2008-08-01

    Full Text Available This paper develops a GIS-based integrated approach to the Multi-Hazard model method, with reference to hurricanes. This approach has three components: data integration, hazard assessment and score calculation to estimate elements at risk such as affected area and affected population. First, spatial data integration issues within a GIS environment, such as geographical scales and data models, are addressed. Particularly, the integration of physical parameters and population data is achieved linking remotely sensed data with a high resolution population distribution in GIS. In order to assess the number of affected people, involving heterogeneous data sources, the selection of spatial analysis units is basic. Second, specific multi-hazard tasks, such as hazard behaviour simulation and elements at risk assessment, are composed in order to understand complex hazard and provide support for decision making. Finally, the paper concludes that the integrated approach herein presented can be used to assist emergency management of hurricane consequences, in theory and in practice.

  15. A Simulation Tool for Hurricane Evacuation Planning

    Directory of Open Access Journals (Sweden)

    Daniel J. Fonseca

    2009-01-01

    Full Text Available Atlantic hurricanes and severe tropical storms are a serious threat for the communities in the Gulf of Mexico region. Such storms are violent and destructive. In response to these dangers, coastal evacuation may be ordered. This paper describes the development of a simulation model to analyze the movement of vehicles through I-65, a major US Interstate highway that runs north off the coastal City of Mobile, Alabama, towards the State of Tennessee, during a massive evacuation originated by a disastrous event such a hurricane. The constructed simulation platform consists of a primary and two secondary models. The primary model is based on the entry of vehicles from the 20 on-ramps to I-65. The two secondary models assist the primary model with related traffic events such as car breakdowns and accidents, traffic control measures, interarrival signaling, and unforeseen emergency incidents, among others. Statistical testing was performed on the data generated by the simulation model to indentify variation in relevant traffic variables affecting the timely flow of vehicles travelling north. The performed statistical analysis focused on the closing of alternative on-ramps throughout the Interstate.

  16. Weathering the storm: hurricanes and birth outcomes.

    Science.gov (United States)

    Currie, Janet; Rossin-Slater, Maya

    2013-05-01

    A growing literature suggests that stressful events in pregnancy can have negative effects on birth outcomes. Some of the estimates in this literature may be affected by small samples, omitted variables, endogenous mobility in response to disasters, and errors in the measurement of gestation, as well as by a mechanical correlation between longer gestation and the probability of having been exposed. We use millions of individual birth records to examine the effects of exposure to hurricanes during pregnancy, and the sensitivity of the estimates to these econometric problems. We find that exposure to a hurricane during pregnancy increases the probability of abnormal conditions of the newborn such as being on a ventilator more than 30min and meconium aspiration syndrome (MAS). Although we are able to reproduce previous estimates of effects on birth weight and gestation, our results suggest that measured effects of stressful events on these outcomes are sensitive to specification and it is preferable to use more sensitive indicators of newborn health. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. Geologic record of Hurricane impacts on the New Jersey coast

    Science.gov (United States)

    Nikitina, Daria; Horton, Benjamin; Khan, Nicole; Clear, Jennifer; Shaw, Timothy; Enache, Mihaela; Frizzera, Dorina; Procopio, Nick; Potapova, Marina

    2016-04-01

    Hurricanes along the US Atlantic coast have caused significant damage and loss of human life over the last century. Recent studies suggest that intense-hurricane activity is closely related to changes of sea surface temperatures and therefore the risk of hurricane strikes may increase in the future. A clear understanding of the role of recent warming on tropical cyclone activity is limited by the shortness of the instrumental record. However, the sediment preserved beneath coastal wetlands is an archive of when hurricanes impacted the coast. We present two complimenting approaches that help to extend pre-historic record and assess frequency and intensity of hurricane landfalls along the New Jersey cost; dating overwash deposits and hurricane-induced salt-marsh erosion documented at multiple sites. The stratigraphic investigation of estuarine salt marshes in the southern New Jersey documented seven distinctive erosion events that correlate among different sites. Radiocarbon dates suggest the prehistoric events occurred in AD 558-673, AD 429-966, AD 558-673, Ad 1278-1438, AD 1526-1558 or AD 1630-1643 (Nikitina et al., 2014). Younger sequences correspond with historical land-falling hurricanes in AD 1903 and AD 1821 or AD 1788. Four events correlate well with barrier overwash deposits documented along the New Jersey coast (Donnelley et al., 2001 and 2004). The stratigraphic sequence of salt High resolution sedimentary-based reconstructions of past intense-hurricane landfalls indicate that significant variability in the frequency of intense hurricanes occurred over the last 2000 years.

  18. On the validity of representing hurricanes as Carnot heat engine

    Directory of Open Access Journals (Sweden)

    A. M. Makarieva

    2008-09-01

    Full Text Available It is argued, on the basis of detailed critique of published literature, that the existing thermodynamic theory of hurricanes, where it is assumed that the hurricane power is formed due to heat input from the ocean, is not physically consistent, as it comes in conflict with the first and second laws of thermodynamics. A quantitative perspective of describing hurricane energetics as that of an adiabatic atmospheric process occurring at the expense of condensation of water vapor that creates drop of local air pressure, is outlined.

  19. Hurricane Relief Operations in the Caribbean: Is the Use of the Military in Hurricane Relief Operations

    Science.gov (United States)

    2007-11-02

    Caribbean hurricanes are a type of tropical cyclone . They originate in the Atlantic Ocean off the coast of Africa and affect the Caribbean and 2 the...that will prove to be more suitable in disaster relief situations. Matthew Yarrow also shares Dynes’ view. He believes that soldiers are ill-suited... Haiti operations, in part due to the battalion commander’s lack of authority over troops from different countries. However, the performance of the

  20. Numerical simulation of the rapid intensification of Hurricane Katrina (2005): Sensitivity to boundary layer parameterization schemes

    Science.gov (United States)

    Liu, Jianjun; Zhang, Feimin; Pu, Zhaoxia

    2017-04-01

    Accurate forecasting of the intensity changes of hurricanes is an important yet challenging problem in numerical weather prediction. The rapid intensification of Hurricane Katrina (2005) before its landfall in the southern US is studied with the Advanced Research version of the WRF (Weather Research and Forecasting) model. The sensitivity of numerical simulations to two popular planetary boundary layer (PBL) schemes, the Mellor-Yamada-Janjic (MYJ) and the Yonsei University (YSU) schemes, is investigated. It is found that, compared with the YSU simulation, the simulation with the MYJ scheme produces better track and intensity evolution, better vortex structure, and more accurate landfall time and location. Large discrepancies (e.g., over 10 hPa in simulated minimum sea level pressure) are found between the two simulations during the rapid intensification period. Further diagnosis indicates that stronger surface fluxes and vertical mixing in the PBL from the simulation with the MYJ scheme lead to enhanced air-sea interaction, which helps generate more realistic simulations of the rapid intensification process. Overall, the results from this study suggest that improved representation of surface fluxes and vertical mixing in the PBL is essential for accurate prediction of hurricane intensity changes.

  1. Wind Retrieval Algorithms for the IWRAP and HIWRAP Airborne Doppler Radars with Applications to Hurricanes

    Science.gov (United States)

    Guimond, Stephen Richard; Tian, Lin; Heymsfield, Gerald M.; Frasier, Stephen J.

    2013-01-01

    Algorithms for the retrieval of atmospheric winds in precipitating systems from downward-pointing, conically-scanning airborne Doppler radars are presented. The focus in the paper is on two radars: the Imaging Wind and Rain Airborne Profiler(IWRAP) and the High-altitude IWRAP (HIWRAP). The IWRAP is a dual-frequency (Cand Ku band), multi-beam (incidence angles of 30 50) system that flies on the NOAAWP-3D aircraft at altitudes of 2-4 km. The HIWRAP is a dual-frequency (Ku and Kaband), dual-beam (incidence angles of 30 and 40) system that flies on the NASA Global Hawk aircraft at altitudes of 18-20 km. Retrievals of the three Cartesian wind components over the entire radar sampling volume are described, which can be determined using either a traditional least squares or variational solution procedure. The random errors in the retrievals are evaluated using both an error propagation analysis and a numerical simulation of a hurricane. These analyses show that the vertical and along-track wind errors have strong across-track dependence with values of 0.25 m s-1 at nadir to 2.0 m s-1 and 1.0 m s-1 at the swath edges, respectively. The across-track wind errors also have across-track structure and are on average, 3.0 3.5 m s-1 or 10 of the hurricane wind speed. For typical rotated figure four flight patterns through hurricanes, the zonal and meridional wind speed errors are 2 3 m s-1.Examples of measured data retrievals from IWRAP during an eyewall replacement cycle in Hurricane Isabel (2003) and from HIWRAP during the development of Tropical Storm Matthew (2010) are shown.

  2. National Assessment of Hurricane-Induced Coastal Erosion Hazards

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set contains information on the probabilities of hurricane-induced erosion (collision, inundation and overwash) for each 1-km section of the United States...

  3. Hurricane Sandy: Rapid Response Imagery of the Surrounding Regions

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The imagery posted on this site is of Hurricane Sandy. The aerial photography missions were conducted by the NOAA Remote Sensing Division. The images were acquired...

  4. Hurricane Sandy, Disaster Preparedness, and the Recovery Model.

    Science.gov (United States)

    Pizzi, Michael A

    2015-01-01

    Hurricane Sandy was the second largest and costliest hurricane in U.S. history to affect multiple states and communities. This article describes the lived experiences of 24 occupational therapy students who lived through Hurricane Sandy using the Recovery Model to frame the research. Occupational therapy student narratives were collected and analyzed using qualitative methods and framed by the Recovery Model. Directed content and thematic analysis was performed using the 10 components of the Recovery Model. The 10 components of the Recovery Model were experienced by or had an impact on the occupational therapy students as they coped and recovered in the aftermath of the natural disaster. This study provides insight into the lived experiences and recovery perspectives of occupational therapy students who experienced Hurricane Sandy. Further research is indicated in applying the Recovery Model to people who survive disasters. Copyright © 2015 by the American Occupational Therapy Association, Inc.

  5. Hurricane Katrina Air Quality Sampling/Daily Monitoring (AQSDM)

    Science.gov (United States)

    Hurricane Katrina made landfall in August 2005, causing widespread devastation along the Gulf Coast of the United States. EPA emergency response personnel worked with FEMA and state and local agencies to respond to the emergencies throughout the Gulf.

  6. ENVIRONMENTAL SAMPLING AND ANALYSIS IN THE AFTERMATH OF HURRICANE KATRINA

    Science.gov (United States)

    This presentation describes the environmental sampling completed by EPA in southeastern Louisiana after Hurricane Katrina caused major catastrophic damage. Presentation also describes EPA's Environmental Unit activities in Baton Rouge and New Orleans, LA, and Dallas, TX.

  7. EMERGENCY RESPONSE FOR PUBLIC WATER SUPPLIES AFTER HURRICANE KATRINA

    Science.gov (United States)

    Hurricane Katrina resulted in damage and destruction to local water supplies in Mississippi and Louisiana affecting millions of people. Immediately following the devastation, a multidisciplinary team of 30 EPA emergency response, research, and water program personnel joined force...

  8. Hurricane Katrina Air Quality Sampling/Daily Monitoring (AQSDM)

    Data.gov (United States)

    U.S. Environmental Protection Agency — Hurricane Katrina made landfall in August 2005, causing widespread devastation along the Gulf Coast of the United States. EPA emergency response personnel worked...

  9. Landslides triggered by Hurricane Mitch in Tegucigalpa, Honduras

    Science.gov (United States)

    Harp, Edwin L.; Castaneda, Mario; Held, Matthew D.

    2002-01-01

    The arrival of Hurricane Mitch in Honduras in the latter part of the 1998 hurricane season produced effects that were unprecedented in their widespread nature throughout Central America. After winds from the storm had blown down more than 70 percent of the conifer forest on the Bay Island of Guanaja, the hurricane turned inland and stalled over the mainland of Honduras for 3 days. The resulting deluge of rainfall produced devastating flooding and landslides that resulted in more than 9,000 fatalities and 3 million people displaced. Although the eye of Hurricane Mitch passed through the northern part of Honduras, the greatest rainfall totals and intensities occurred in the southern part of the country near Choluteca. For the three days October 29-31, 1998, total rainfall at Choluteca exceeded 900 mm. Not surprisingly, it was in this area that the highest landslide concentrations occurred.

  10. Using new satellite data would improve hurricane forecasts

    National Research Council Canada - National Science Library

    Schultz, Colin

    2013-01-01

    To track and forecast the development of dangerous tropical cyclones, the National Weather Service's National Centers for Environmental Prediction uses a model known as the Hurricane Weather Research and Forecasting (HWRF) system...

  11. Fuel for cyclones: How the water vapor budget of a hurricane depends on its motion

    CERN Document Server

    Makarieva, Anastassia M; Nefiodov, Andrei V; Chikunov, Alexander V; Sheil, Douglas; Nobre, Antonio D; Li, Bai-Lian

    2016-01-01

    Tropical cyclones are fueled by water vapor. Here we estimate the oceanic evaporation within an Atlantic hurricane to be less than one sixth of the total moisture flux precipitating over the same area. So how does the hurricane get the remaining water vapor? Our analysis of TRMM rainfall, MERRA atmospheric moisture and hurricane translation velocities suggests that access to water vapor relies on the hurricane's motion -- as it moves through the atmosphere, the hurricane consumes the water vapor it encounters. This depletion of atmospheric moisture by the hurricane leaves a "dry footprint" of suppressed rainfall in its wake. The thermodynamic efficiency of hurricanes -- defined as kinetic energy production divided by total latent heat release associated with the atmospheric moisture supply -- remains several times lower than Carnot efficiency even in the most intense hurricanes. Thus, maximum observed hurricane power cannot be explained by the thermodynamic Carnot limit.

  12. Seismic and pressure signals when a hurricane moves over an array

    Science.gov (United States)

    Tanimoto, Toshiro

    2017-04-01

    General structure in a tropical cyclone (hurricane/typhoon) in the atmosphere is reasonably well known; it has a very calm central region surrounded by a circular eyewall at a radius of about 50-100 km from the center. Winds are strongest at the eyewall and outside the eyewall, there exists a fairly strong windy region that extends to about 500-1000 km from the center. The main purpose of this study is to understand how seismic waves in the solid Earth are generated by a tropical cyclone. We focus on a low frequency band (below 0.05 Hz) in this study. The basic mechanism of seismic wave excitation in such a low frequency band is relatively straightforward; changes in wind speed generate surface pressure changes and that in turn excite ground motions in the solid Earth. In a rare example of a hurricane (Hurricane Isaac in 2012) that moved through the USARRAY (Earthscope), that had co-located seismometers and barometers, we can directly examine how ground motions and surface pressure are influenced by the passage of a hurricane eye. When a hurricane eye passes over a station, pressure and three-component seismic time series show a gap in amplitude (envelope) for filtered time series below 0.05 Hz. Typically, long envelopes in time series appear to be truncated by a gap that is at the arrival time of the hurricane eye (although it is not a real gap in data). Using a few stations on the track of a hurricane, we can show that this gap moves in time. This feature only occurs for stations that are within about 50 km from the hurricane track. We also point out that pressure and vertical ground motions show very high correlation (the correlation coefficient or CC about 0.8-0.9). On the other hand, horizontal-component seismic data show small correlation with pressure (CC close to zero) even though their amplitudes (envelopes) show gaps that are coincident in time with pressure. What it means is that phase is quite incoherent between pressure and horizontal components

  13. Divine Wind - The History and Science of Hurricanes

    Science.gov (United States)

    Emanuel, Kerry

    2005-09-01

    Imagine standing at the center of a Roman coliseum that is 20 miles across, with walls that soar 10 miles into the sky, towering walls with cascades of ice crystals falling along its brilliantly white surface. That's what it's like to stand in the eye of a hurricane. In Divine Wind , Kerry Emanuel, one of the world's leading authorities on hurricanes, gives us an engaging account of these awe-inspiring meteorological events, revealing how hurricanes and typhoons have literally altered human history, thwarting military incursions and changing the course of explorations. Offering an account of the physics of the tropical atmosphere, the author explains how such benign climates give rise to the most powerful storms in the world and tells what modern science has learned about them. Interwoven with this scientific account are descriptions of some of the most important hurricanes in history and relevant works of art and literature. For instance, he describes the 17th-century hurricane that likely inspired Shakespeare's The Tempest and that led to the British colonization of Bermuda. We also read about the Galveston Hurricane of 1900, by far the worst natural calamity in U.S. history, with a death toll between 8,000 and 12,000 that exceeded the San Francisco earthquake, the Johnstown Flood, and the Okeechobee Hurricane combined. Boasting more than one hundred color illustrations, from ultra-modern Doppler imagery to classic paintings by Winslow Homer, Divine Wind captures the profound effects that hurricanes have had on humanity. Its fascinating blend of history, science, and art will appeal to weather junkies, science buffs, and everyone who read Isaac's Storm .

  14. A team approach to preparing for hurricanes and other disasters.

    Science.gov (United States)

    Kendig, Jim

    2009-01-01

    Applying lessons learned in Hurricane Floyd in 1999, a three-hospital system located on Florida's exposed Space Coast was able to better deal with the devastation caused by hurricanes in 2004 and make changes in its plans to better prepare for the named storms which hit its area in 2008. Each new disaster, the author points out, brings with it new challenges which have to be considered in disaster planning.

  15. Mangrove forest recovery in the Everglades following Hurricane Wilma

    Science.gov (United States)

    Sarmiento, Daniel; Barr, Jordan; Engel, Vic; Fuentes, Jose D.; Smith, Thomas J.; Zieman, Jay C.

    2009-01-01

    On October 24th, 2005, Hurricane Wilma made landfall on the south western shore of the Florida peninsula. This major disturbance destroyed approximately 30 percent of the mangrove forests in the area. However, the damage to the ecosystem following the hurricane provided researchers at the Florida Coastal Everglades (FCE) LTER site with the rare opportunity to track the recovery process of the mangroves as determined by carbon dioxide (CO2) and energy exchanges, measured along daily and seasonal time scales.

  16. Hurricane Katrina: Impact on Cardiac Surgery Case Volume and Outcomes

    OpenAIRE

    Bakaeen, Faisal G.; Huh, Joseph; Chu, Danny; Coselli, Joseph S.; LeMaire, Scott A.; Mattox, Kenneth L.; Wall, Matthew J.; Wang, Xing Li; Shenaq, Salwa A.; Atluri, Prasad V.; Awad, Samir S.; Berger, David H.

    2008-01-01

    Hurricane Katrina produced a surge of patient referrals to our facility for cardiac surgery. We sought to determine the impact of this abrupt volume change on operative outcomes. Using our cardiac surgery database, which is part of the Department of Veterans Affairs' Continuous Improvement in Cardiac Surgery Program, we compared procedural outcomes for all cardiac operations that were performed in the year before the hurricane (Year A, 29 August 2004–28 August 2005) and the year after (Year B...

  17. Hospitalization rates among dialysis patients during Hurricane Katrina.

    Science.gov (United States)

    Howard, David; Zhang, Rebecca; Huang, Yijian; Kutner, Nancy

    2012-08-01

    Dialysis centers struggled to maintain continuity of care for dialysis patients during and immediately following Hurricane Katrina's landfall on the US Gulf Coast in August 2005. However, the impact on patient health and service use is unclear. The impact of Hurricane Katrina on hospitalization rates among dialysis patients was estimated. Data from the United States Renal Data System were used to identify patients receiving dialysis from January 1, 2001 through August 29, 2005 at clinics that experienced service disruptions during Hurricane Katrina. A repeated events duration model was used with a time-varying Hurricane Katrina indicator to estimate trends in hospitalization rates. Trends were estimated separately by cause: surgical hospitalizations, medical, non-renal-related hospitalizations, and renal-related hospitalizations. The rate ratio for all-cause hospitalization associated with the time-varying Hurricane Katrina indicator was 1.16 (95% CI, 1.05-1.29; P = .004). The ratios for cause-specific hospitalization were: surgery, 0.84 (95% CI, 0.68-1.04; P = .11); renal-related admissions, 2.53 (95% CI, 2.09-3.06); P Katrina was 140, representing approximately three percent of dialysis patients at the affected clinics. Hospitalization rates among dialysis patients increased in the month following the Hurricane Katrina landfall, suggesting that providers and patients were not adequately prepared for large-scale disasters.

  18. 2006 United States Army Corps of Engineers (USACE) Post Hurricane Wilma Lidar: Hurricane Pass to Big Hickory Pass, FL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data contained in these files contain hydrographic and topographic data collected by the CHARTS system along the west coast of Florida from Hurricane Pass to Big...

  19. Analyzing after-action reports from Hurricanes Andrew and Katrina: repeated, modified, and newly created recommendations.

    Science.gov (United States)

    Knox, Claire Connolly

    2013-01-01

    Thirteen years after Hurricane Andrew struck Homestead, FL, Hurricane Katrina devastated the Gulf Coast of Mississippi, Alabama, and southeastern Louisiana. Along with all its destruction, the term "catastrophic" was redefined. This article extends the literature on these hurricanes by providing a macrolevel analysis of The Governor's Disaster Planning and Response Review Committee Final Report from Hurricane Andrew and three federal after-action reports from Hurricane Katrina, as well as a cursory review of relevant literature. Results provide evidence that previous lessons have not been learned or institutionalized with many recommendations being repeated or modified. This article concludes with a discussion of these lessons, as well as new issues arising during Hurricane Katrina.

  20. Evaluation of GPM candidate algorithms on hurricane observations

    Science.gov (United States)

    Le, M.; Chandrasekar, C. V.

    2012-12-01

    The observation of precipitation on a global scale by the Tropical Rain Measuring Mission (TRMM) precipitation radar (PR) and has enabled a large scale study of precipitation over ocean, especially tropical storms. The three-dimensional downward-looking observation characteristic of the TRMM-PR makes it possible to study the vertical structure of tropical storms. The global precipitation measuring mission (GPM) will be the second mission following the success of TRMM. The GPM Mission extends tropical storm tracking and forecasting capabilities into the middle and high latitudes, covering the area from 65° S to 65°N. This orbit will provide new insight into how and why some tropical storm intensify and others weaken as they move from tropical to mid-latitude systems. The GPM core satellite will be equipped with a dual-frequency precipitation radar (DPR) operating at K_u (13.6 GHz) and K_a (35.5 GHz) band. DPR on aboard the GPM core satellite is expected to improve our knowledge of precipitation processes relative to the single-frequency (K_u band) radar used in TRMM by providing greater dynamic range, more detailed information on microphysics, and better accuracies in rainfall retrievals. New K_a band channel observation of DPR will help to improve the detection thresholds for light rain and snow relative to TRMM PR [1]. The dual-frequency signals will allow us to better distinguish regions of liquid, frozen, and mixed-phase precipitation. In the GPM era, storms could be better tracked and characterized. In support the NASA GPM mission, NASA JPL (Jet Propulsion Lab) developed the 2nd generation Airborne Precipitation Radar (APR-2) as a prototype of advanced dual-frequency space radar which emulates DPR on board the GPM core satellite before it is launched. GRIP (Genesis and Rapid Intensification Processes) is the most recent campaign of APR-2 conducted in the year 2010 located in Golf of Mexico and Caribbean sea with the major goal to better understand tropical

  1. The effect of DC Joule-heating on magnetic structure of conventional amorphous wires

    Science.gov (United States)

    Aştefănoaei, Iordana; Stancu, Alexandru; Chiriac, Horia

    2007-09-01

    In this paper, we determined the effect of DC Joule-heating on magnetic structure of conventional amorphous wires starting from the stresses that appear during preparation process. For a specified value of applied electrical DC current to some amorphous wires, we have analyzed the thermal stresses that appear during the thermal treatment and we calculated the radius of axial magnetic domain (cylindrical inner core) that results after the preparation and annealing processes. We have obtained that: (a) the total stresses (owing to the successive heating, crystallization and cooling) depend strongly on the applied electrical DC current and the radius of the wires; (b) the axial magnetic domain is bigger for the wire having a bigger radius; (c) the cylindrical inner core enlarges significantly after DC Joule-heating; and (d) smaller internal stresses are obtained at smaller values of the wire's radius.

  2. Controlling a hurricane by altering its internal climate

    Science.gov (United States)

    Mardhekar, D.

    2010-09-01

    Atmospheric hazards, like the fury of a hurricane, can be controlled by altering its internal climate. The hurricane controlling technique suggested is eco-friendly, compatible with hurricane size, has a sound scientific base and is practically possible. The key factor is a large scale dilution of the hurricane fuel, vapour, in the eye wall and spiral rain bands where condensation causing vapor volume reduction (a new concept which can be explained by Avogadro's law) and latent heat release drive the storm. This can be achieved by installing multiple storage tanks containing dry liquefied air on the onshore and offshore coastal regions and islands, preferably underground, in the usual path of a hurricane. Each storage tank is designed to hold and release dry liquefied air of around 100,000 tons. Satellite tracking of hurricanes can locate the eye wall and the spiral rain bands. The installed storage tanks coming under these areas will rapidly inject dry air in huge quantities thereby diluting the vapour content of the vapour-rich air in the eye wall and in the spiral rain bands. This will result in reduced natural input of vapour-rich air, reduced release of latent heat, reduced formation of the low pressure zone due to condensation and volume reduction of the vapor, expansion of the artificially introduced dry air as it goes up occupying a larger space with the diluted fuel, absorption of energy from the system by low temperature of the artificially introduced air. It will effect considerable condensation of the vapor near the sea surface thus further starving the hurricane of its fuel in its engine. Seeding materials, or microscopic dust as suggested by Dr. Daniel Rosenfeld in large quantities may also be introduced via the flow of the injected dry air in order to enhance the hurricane controlling ability. All the above factors are in favour of retarding the hurricane's wind speed and power. The sudden weakening of hurricane Lili was found to be partially caused

  3. Differences in impacts of Hurricane Sandy on freshwater swamps on the Delmarva Peninsula, Mid−Atlantic Coast, USA

    Science.gov (United States)

    Middleton, Beth A.

    2016-01-01

    Hurricane wind and surge may have different influences on the subsequent composition of forests. During Hurricane Sandy, while damaging winds were highest near landfall in New Jersey, inundation occurred along the entire eastern seaboard from Georgia to Maine. In this study, a comparison of damage from salinity intrusion vs. wind/surge was recorded in swamps of the Delmarva Peninsula along the Pocomoke (MD) and Nanticoke (DE) Rivers, south of the most intense wind damage. Hickory Point Cypress Swamp (Hickory) was closest to the Chesapeake Bay and may have been subjected to a salinity surge as evidenced by elevated salinity levels at a gage upstream of this swamp (storm salinity = 13.1 ppt at Nassawango Creek, Snow Hill, Maryland). After Hurricane Sandy, 8% of the standing trees died at Hickory including Acer rubrum, Amelanchier laevis, Ilex spp., and Taxodium distichum. In Plot 2 of Hickory, 25% of the standing trees were dead, and soil salinity levels were the highest recorded in the study. The most important variables related to structural tree damage were soil salinity and proximity to the Atlantic coast as based on Stepwise Regression and NMDS procedures. Wind damage was mostly restricted to broken branches although tipped−up trees were found at Hickory, Whiton and Porter (species: Liquidamabar styraciflua, Pinus taeda, Populus deltoides, Quercus pagoda and Ilex spp.). These trees fell mostly in an east or east−southeast direction (88o−107o) in keeping with the wind direction of Hurricane Sandy on the Delmarva Peninsula. Coastal restoration and management can be informed by the specific differences in hurricane damage to vegetation by salt versus wind.

  4. Hurricane Impacts on Small Island Communities: Case study of Hurricane Matthew on Great Exuma, The Bahamas

    Science.gov (United States)

    Sullivan Sealey, Kathleen; Bowleg, John

    2017-04-01

    Great Exuma has been a UNESCO Eco-hydrology Project Site with a focus on coastal restoration and flood management. Great Exuma and its largest settlement, George Town, support a population of just over 8.000 people on an island dominated by extensive coastal wetlands. The Victoria Pond Eco-Hydrology project restored flow and drainage to highly-altered coastal wetlands to reduce flooding of the built environment as well as regain ecological function. The project was designed to show the value of a protected wetland and coastal environment within a populated settlement; demonstrating that people can live alongside mangroves and value "green" infrastructure for flood protection. The restoration project was initiated after severe storm flooding in 2007 with Tropical Storm Noel. In 2016, the passing of Hurricane Matthew had unprecedented impacts on the coastal communities of Great Exuma, challenging past practices in restoration and flood prevention. This talk reviews the loss of natural capital (for example, fish populations, mangroves, salt water inundation) from Hurricane Matthew based on a rapid response survey of Great Exuma. The surprisingly find was the impact of storm surge on low-lying areas used primarily for personal farms and small-scale agriculture. Although women made up the overwhelming majority of people who attended Coastal Restoration workshops, women were most adversely impacted by the recent hurricane flooding with the loss of their small low-lying farms and gardens. Although increasing culverts in mangrove creeks in two areas did reduce building flood damage, the low-lying areas adjacent to mangroves, mostly ephemeral freshwater wetlands, were inundated with saltwater, and seasonal crops in these areas were destroyed. These ephemeral wetlands were designed as part of the wetland flooding system, it was not known how important these small areas were to artisanal farming on Great Exuma. The size and scope of Hurricane Matthew passing through the

  5. Increases in gonorrhea among high school students following hurricane Katrina.

    Science.gov (United States)

    Nsuami, M J; Taylor, S N; Smith, B S; Martin, D H

    2009-06-01

    To determine the prevalence of Neisseria gonorrhoeae in a student population before hurricane Katrina and after their residential neighbourhoods were devastated in the wake of the hurricane. Students in a New Orleans public high school were offered urine screening for N gonorrhoeae and Chlamydia trachomatis using nucleic acid amplification tests before (n = 346) and after (n = 333) hurricane Katrina. Based on studies showing gonorrhea clustering in physically deteriorated neighbourhoods, it was hypothesised that the post-Katrina gonorrhea prevalence would be higher among students whose neighbourhoods still showed signs of deterioration in the aftermath of the hurricane. Before and after hurricane Katrina, the prevalence of gonorrhea increased from 2.3% (8/346, 95% CI 1.3% to 4.6%) to 5.1% (17/333, 95% CI 3.1% to 8.2%), respectively (one-sided p = 0.027). In logistic regression of gonorrhea controlling for gender, age, chlamydia infection and exposure to hurricane-affected residential neighbourhood conditions, gonorrhea was significantly associated with female gender (odds ratio (OR) 2.6, 95% CI 1.0 to 6.3; p = 0.04) and with chlamydia infection (OR 9.2, 95% CI 3.9 to 21.7; phurricane (OR 2.2, 95% CI 0.9 to 5.4; p = 0.09). The analysis indicates that the odds of testing positive for gonorrhea more than doubled among students after the hurricane, indicating that surveillance activities should be restored to monitor sexually transmitted infections (STIs) among at-risk populations. Redoubled efforts should be put into STI screening programmes as soon as possible following natural disasters to prevent resurgent STI incidence rates.

  6. Aftermath of Hurricane Ike along Texas Coast

    Science.gov (United States)

    2008-01-01

    Three weeks after Hurricane Ike came ashore near Galveston, TX, residents returned to find their houses in ruins. From the coast to over 15 km inland, salt water saturated the soil as a result of the 7m storm surge pushed ashore by the force of the hurricane. The right image was acquired on September 28; the left image was acquired August 15, 2006. Vegetation is displayed in red, and inundated areas are in blue-green. Within the inundated area are several small 'red islands' of high ground where salt domes raised the level of the land, and protected the vegetation. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER images Earth to map and monitor the changing surface of our planet. ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping, and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance. The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate. Size: 37 by 49.5 kilometers (22.8 by 30.6 miles) Location: 29.8 degrees North latitude, 94.4 degrees West longitude Orientation: North at top Image Data: ASTER Bands 3, 2, and

  7. Aftermath of Hurricane Ike along Texas Coast

    Science.gov (United States)

    2008-01-01

    Three weeks after Hurricane Ike came ashore near Galveston, TX, residents returned to find their houses in ruins. From the coast to over 15 km inland, salt water saturated the soil as a result of the 7m storm surge pushed ashore by the force of the hurricane. The right image was acquired on September 28; the left image was acquired August 15, 2006. Vegetation is displayed in red, and inundated areas are in blue-green. Within the inundated area are several small 'red islands' of high ground where salt domes raised the level of the land, and protected the vegetation. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER images Earth to map and monitor the changing surface of our planet. ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping, and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance. The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate. Size: 37 by 49.5 kilometers (22.8 by 30.6 miles) Location: 29.8 degrees North latitude, 94.4 degrees West longitude Orientation: North at top Image Data: ASTER Bands 3, 2, and

  8. EAARL Coastal Topography--Eastern Florida, Post-Hurricane Jeanne, 2004: Bare Earth

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A digital elevation model (DEM) of a portion of the eastern Florida coastline, post-Hurricane Jeanne (September 2004 hurricane), was produced from remotely sensed,...

  9. EAARL Coastal Topography--Eastern Florida, Post-Hurricane Jeanne, 2004: First Surface

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A digital elevation model (DEM) of a portion of the eastern Florida coastline, post-Hurricane Jeanne (September 2004 hurricane), was produced from remotely sensed,...

  10. Coastal Topography--Northeast Atlantic Coast, Post-Hurricane Sandy, 2012

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Derived products of a portion of the New York, Delaware, Maryland, Virginia, and North Carolina coastlines, post-Hurricane Sandy (Sandy was an October 2012 hurricane...

  11. EAARL Coastal Topography--Mississippi and Alabama Barrier Islands, Post-Hurricane Gustav, 2008

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A digital elevation model (DEM) of a portion of the Mississippi and Alabama barrier islands, post-Hurricane Gustav (September 2008 hurricane), was produced from...

  12. 2012-2013 Post-Hurricane Sandy EAARL-B Submerged Topography - Barnegat Bay, New Jersey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Binary point-cloud data for part of Barnegat Bay, New Jersey, post-Hurricane Sandy (October 2012 hurricane), were produced from remotely sensed, geographically...

  13. Comparison of hurricane exposure methods and associations with county fetal death rates, adjusting for environmental quality

    Science.gov (United States)

    Adverse effects of hurricanes are increasing as coastal populations grow and events become more severe. Hurricane exposure during pregnancy can influence fetal death rates through mechanisms related to healthcare, infrastructure disruption, nutrition, and injury. Estimation of hu...

  14. Tropical Storm Frances/ Hurricane Ivan Situation Report, September 10, 2014 (10:00 AM EDT)

    Energy Technology Data Exchange (ETDEWEB)

    None

    2004-09-10

    The report provides highlights related to impacts of Hurricane Frances and Hurricane Ivan in the Florida area. Sections on electric information, oil and gas information, county outage data, and a table for restoration targets/status are provided.

  15. Tropical Storm Frances and Hurricane Ivan Situation Report, September 9, 2004 (10:00 PM EDT)

    Energy Technology Data Exchange (ETDEWEB)

    None

    2004-09-09

    The report provides highlights related to impacts of Hurricane Frances and Hurricane Ivan in the Florida area. Sections on electric information, oil and gas information, and county outage data are provided.

  16. EAARL Coastal Topography--Eastern Louisiana Barrier Islands, Post-Hurricane Gustav, 2008: First Surface

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A digital elevation model (DEM) of a portion of the eastern Louisiana barrier islands, post-Hurricane Gustav (September 2008 hurricane), was produced from remotely...

  17. EAARL Coastal Topography--Eastern Florida, Post-Hurricane Jeanne, 2004: Bare Earth

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A digital elevation model (DEM) of a portion of the eastern Florida coastline, post-Hurricane Jeanne (September 2004 hurricane), was produced from remotely sensed,...

  18. EAARL Coastal Topography--Eastern Florida, Post-Hurricane Jeanne, 2004: First Surface

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A digital elevation model (DEM) of a portion of the eastern Florida coastline, post-Hurricane Jeanne (September 2004 hurricane), was produced from remotely sensed,...

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

    Data.gov (United States)

    U.S. Environmental Protection Agency — 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...

  20. EAARL Coastal Topography--Mississippi and Alabama Barrier Islands, Post-Hurricane Gustav, 2008

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A digital elevation model (DEM) of a portion of the Mississippi and Alabama barrier islands, post-Hurricane Gustav (September 2008 hurricane), was produced from...

  1. EAARL Coastal Topography--Eastern Louisiana Barrier Islands, Post-Hurricane Gustav, 2008: First Surface

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — A digital elevation model (DEM) of a portion of the eastern Louisiana barrier islands, post-Hurricane Gustav (September 2008 hurricane), was produced from remotely...

  2. Mapping Hurricane Rita inland storm tide

    Science.gov (United States)

    Berenbrock, Charles; Mason, Jr., Robert R.; Blanchard, Stephen F.; Simonovic, Slobodan P.

    2009-01-01

    Flood-inundation data are most useful for decision makers when presented in the context of maps of effected communities and (or) areas. But because the data are scarce and rarely cover the full extent of the flooding, interpolation and extrapolation of the information are needed. Many geographic information systems (GIS) provide various interpolation tools, but these tools often ignore the effects of the topographic and hydraulic features that influence flooding. A barrier mapping method was developed to improve maps of storm tide produced by Hurricane Rita. Maps were developed for the maximum storm tide and at 3-hour intervals from midnight (0000 hour) through noon (1200 hour) on September 24, 2005. The improved maps depict storm-tide elevations and the extent of flooding. The extent of storm-tide inundation from the improved maximum storm-tide map was compared to the extent of flood-inundation from a map prepared by the Federal Emergency Management Agency (FEMA). The boundaries from these two maps generally compared quite well especially along the Calcasieu River. Also a cross-section profile that parallels the Louisiana coast was developed from the maximum storm-tide map and included FEMA high-water marks.

  3. Through Hell and High Water: A Librarian’s Autoethnography of Community Resilience after Hurricane Katrina

    Directory of Open Access Journals (Sweden)

    Beth Patin

    2016-02-01

    Full Text Available This autoethnographic essay presents a critical reflection on personal experiences of the process of rebuilding and working in a library in the Lower Ninth Ward in New Orleans, Louisiana following Hurricane Katrina. I examine meaningful moments during this process in the context of information science and community resiliency. The framework of community resilience is used to help structure the reflection and analysis in a systematic way. I share examples of the adaptive capacities of the school library as evidence of how the community adjusted to demonstrate resiliency.

  4. Hurricane Sandy science plan: coastal topographic and bathymetric data to support hurricane impact assessment and response

    Science.gov (United States)

    Stronko, Jakob M.

    2013-01-01

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

  5. The Hurricane-Flood-Landslide Continuum: Forecasting Hurricane Effects at Landfall

    Science.gov (United States)

    Negri, A.; Golden, J. H.; Updike, R.

    2004-01-01

    Hurricanes, typhoons, and cyclones strike Central American, Caribbean, Southeast Asian and Pacific Island nations even more frequently than the U.S. The global losses of life and property from the floods, landslides and debris flows caused by cyclonic storms are staggering. One of the keys to reducing these losses, both in the U.S. and internationally, is to have better forecasts of what is about to happen from several hours to days before the event. Particularly in developing nations where science, technology and communication are limited, advance-warning systems can have great impact. In developing countries, warnings of even a few hours or days can mitigate or reduce catastrophic losses of life. With the foregoing needs in mind, we propose an initial project of three years total duration that will aim to develop and transfer a warning system for a prototype region in the Central Caribbean, specifically the islands of Puerto Rico and Hispanola. The Hurricane-Flood-Landslide Continuum will include satellite observations to track and nowcast dangerous levels of precipitation, atmospheric and hydrological models to predict near-future runoff, and streamflow changes in affected regions, and landslide models to warn when and where landslides and debris flows are imminent. Since surface communications are likely to be interrupted during these crises, the project also includes the capability to communicate disaster information via satellite to vital government officials in Puerto Rico, Haiti, and Dominican Republic.

  6. Hurricane Risk Variability along the Gulf of Mexico Coastline

    Science.gov (United States)

    Trepanier, Jill C.; Ellis, Kelsey N.; Tucker, Clay S.

    2015-01-01

    Hurricane risk characteristics are examined across the U. S. Gulf of Mexico coastline using a hexagonal tessellation. Using an extreme value model, parameters are collected representing the rate or λ (frequency), the scale or σ (range), and the shape or ξ (intensity) of the extreme wind distribution. These latent parameters and the 30-year return level are visualized across the grid. The greatest 30-year return levels are located toward the center of the Gulf of Mexico, and for inland locations, along the borders of Louisiana, Mississippi, and Alabama. Using a geographically weighted regression model, the relationship of these parameters to sea surface temperature (SST) is found to assess sensitivity to change. It is shown that as SSTs increase near the coast, the frequency of hurricanes in these grids decrease significantly. This reinforces the importance of SST in areas of likely tropical cyclogenesis in determining the number of hurricanes near the coast, along with SSTs along the lifespan of the storm, rather than simply local SST. The range of hurricane wind speeds experienced near Florida is shown to increase with increasing SSTs (insignificant), suggesting that increased temperatures may allow hurricanes to maintain their strength as they pass over the Florida peninsula. The modifiable areal unit problem is assessed using multiple grid sizes. Moran’s I and the local statistic G are calculated to examine spatial autocorrelation in the parameters. This research opens up future questions regarding rapid intensification and decay close to the coast and the relationship to changing SSTs. PMID:25767885

  7. Recent Developments of the Florida Public Hurricane Loss Model

    Science.gov (United States)

    Cocke, S.; Shin, D. W.; Annane, B.

    2016-12-01

    Catastrophe models are used extensively by the insurance industry to estimate losses due to natural hazards such as hurricanes and earthquakes. In the state of Florida, primary insurers for hurricane damage to residential properties are required by law to use certified catastrophe models to establish their premiums and capital reserves. The Florida Public Hurricane Loss Model (FPHLM) is one of only five certified catastrophe models in Florida, and the only non-commercial model certified. The FPHLM has been funded through the Florida Legislature and is overseen by the Florida Office of Insurance Regulation (OIR). The model was developed by a consortium of universities and private consultants primary located in Florida, but includes some partners outside of the state. The FPHLM has met Florida requirements since 2006 and has undergone continuous evolution to maintain state-of-the-art capabilities and changes in state requirements established by the Florida Commission on Hurricane Loss Projection Methodology. Recently the model has been undergoing major enhancement to incorporate damage due to flooding, which not only includes hurricane floods but floods due to all potential natural hazards. This work is being done in anticipation of future changes in the National Flood Insurance Program (NFIP) that will bring private insurers to the flood market. The model will incorporate a surge model as well as an inland flood model. We will present progress on these recent enhancements along with additional progress of the model.

  8. Deaths associated with Hurricane Sandy - October-November 2012.

    Science.gov (United States)

    2013-05-24

    On October 29, 2012, Hurricane Sandy hit the northeastern U.S. coastline. Sandy's tropical storm winds stretched over 900 miles (1,440 km), causing storm surges and destruction over a larger area than that affected by hurricanes with more intensity but narrower paths. Based on storm surge predictions, mandatory evacuations were ordered on October 28, including for New York City's Evacuation Zone A, the coastal zone at risk for flooding from any hurricane. By October 31, the region had 6-12 inches (15-30 cm) of precipitation, 7-8 million customers without power, approximately 20,000 persons in shelters, and news reports of numerous fatalities (Robert Neurath, CDC, personal communication, 2013). To characterize deaths related to Sandy, CDC analyzed data on 117 hurricane-related deaths captured by American Red Cross (Red Cross) mortality tracking during October 28-November 30, 2012. This report describes the results of that analysis, which found drowning was the most common cause of death related to Sandy, and 45% of drowning deaths occurred in flooded homes in Evacuation Zone A. Drowning is a leading cause of hurricane death but is preventable with advance warning systems and evacuation plans. Emergency plans should ensure that persons receive and comprehend evacuation messages and have the necessary resources to comply with them.

  9. Thermal Modeling and Analysis of the Hurricane Imaging Radiometer (HIRad)

    Science.gov (United States)

    Mauro, Stephanie

    2013-01-01

    The Hurricane Imaging Radiometer (HIRad) is a payload carried by an unmanned aerial vehicle (UAV) at altitudes up to 60,000 ft with the purpose of measuring ocean surface wind speeds and near ocean surface rain rates in hurricanes. The payload includes several components that must maintain steady temperatures throughout the flight. Minimizing the temperature drift of these components allows for accurate data collection and conclusions to be drawn concerning the behavior of hurricanes. HIRad has flown on several different UAVs over the past two years during the fall hurricane season. Based on the data from the 2011 flight, a Thermal Desktop model was created to simulate the payload and reproduce the temperatures. Using this model, recommendations were made to reduce the temperature drift through the use of heaters controlled by resistance temperature detector (RTD) sensors. The suggestions made were implemented for the 2012 hurricane season and further data was collected. The implementation of the heaters reduced the temperature drift for a portion of the flight, but after a period of time, the temperatures rose. With this new flight data, the thermal model was updated and correlated. Detailed analysis was conducted to determine a more effective way to reduce the temperature drift. The final recommendations made were to adjust the set temperatures of the heaters for 2013 flights and implement hardware changes for flights beyond 2013.

  10. Hurricanes accelerated the Florida-Bahamas lionfish invasion.

    Science.gov (United States)

    Johnston, Matthew W; Purkis, Sam J

    2015-06-01

    In this study, we demonstrate how perturbations to the Florida Current caused by hurricanes are relevant to the spread of invasive lionfish from Florida to the Bahamas. Without such perturbations, this current represents a potential barrier to the transport of planktonic lionfish eggs and larvae across the Straits of Florida. We further show that once lionfish became established in the Bahamas, hurricanes significantly hastened their spread through the island chain. We gain these insights through: (1) an analysis of the direction and velocity of simulated ocean currents during the passage of hurricanes through the Florida Straits and (2) the development of a biophysical model that incorporates the tolerances of lionfish to ocean climate, their reproductive strategy, and duration that the larvae remain viable in the water column. On the basis of this work, we identify 23 occasions between the years 1992 and 2006 in which lionfish were provided the opportunity to breach the Florida Current. We also find that hurricanes during this period increased the rate of spread of lionfish through the Bahamas by more than 45% and magnified its population by at least 15%. Beyond invasive lionfish, we suggest that extreme weather events such as hurricanes likely help to homogenize the gene pool for all Caribbean marine species susceptible to transport. © 2015 John Wiley & Sons Ltd.

  11. Hurricane risk variability along the Gulf of Mexico coastline.

    Directory of Open Access Journals (Sweden)

    Jill C Trepanier

    Full Text Available Hurricane risk characteristics are examined across the U. S. Gulf of Mexico coastline using a hexagonal tessellation. Using an extreme value model, parameters are collected representing the rate or λ (frequency, the scale or σ (range, and the shape or ξ (intensity of the extreme wind distribution. These latent parameters and the 30-year return level are visualized across the grid. The greatest 30-year return levels are located toward the center of the Gulf of Mexico, and for inland locations, along the borders of Louisiana, Mississippi, and Alabama. Using a geographically weighted regression model, the relationship of these parameters to sea surface temperature (SST is found to assess sensitivity to change. It is shown that as SSTs increase near the coast, the frequency of hurricanes in these grids decrease significantly. This reinforces the importance of SST in areas of likely tropical cyclogenesis in determining the number of hurricanes near the coast, along with SSTs along the lifespan of the storm, rather than simply local SST. The range of hurricane wind speeds experienced near Florida is shown to increase with increasing SSTs (insignificant, suggesting that increased temperatures may allow hurricanes to maintain their strength as they pass over the Florida peninsula. The modifiable areal unit problem is assessed using multiple grid sizes. Moran's I and the local statistic G are calculated to examine spatial autocorrelation in the parameters. This research opens up future questions regarding rapid intensification and decay close to the coast and the relationship to changing SSTs.

  12. Hurricane risk variability along the Gulf of Mexico coastline.

    Science.gov (United States)

    Trepanier, Jill C; Ellis, Kelsey N; Tucker, Clay S

    2015-01-01

    Hurricane risk characteristics are examined across the U. S. Gulf of Mexico coastline using a hexagonal tessellation. Using an extreme value model, parameters are collected representing the rate or λ (frequency), the scale or σ (range), and the shape or ξ (intensity) of the extreme wind distribution. These latent parameters and the 30-year return level are visualized across the grid. The greatest 30-year return levels are located toward the center of the Gulf of Mexico, and for inland locations, along the borders of Louisiana, Mississippi, and Alabama. Using a geographically weighted regression model, the relationship of these parameters to sea surface temperature (SST) is found to assess sensitivity to change. It is shown that as SSTs increase near the coast, the frequency of hurricanes in these grids decrease significantly. This reinforces the importance of SST in areas of likely tropical cyclogenesis in determining the number of hurricanes near the coast, along with SSTs along the lifespan of the storm, rather than simply local SST. The range of hurricane wind speeds experienced near Florida is shown to increase with increasing SSTs (insignificant), suggesting that increased temperatures may allow hurricanes to maintain their strength as they pass over the Florida peninsula. The modifiable areal unit problem is assessed using multiple grid sizes. Moran's I and the local statistic G are calculated to examine spatial autocorrelation in the parameters. This research opens up future questions regarding rapid intensification and decay close to the coast and the relationship to changing SSTs.

  13. Changes in trace metals in Thalassia testudinum after hurricane impacts.

    Science.gov (United States)

    Whelan, T; Van Tussenbroek, B I; Santos, M G Barba

    2011-12-01

    Major hurricanes Emily and Wilma hit the Mexican Caribbean in 2005. Changes in trace metals in the seagrass Thalassia testudinum prior to (May 2004, 2005) and following passage of these hurricanes (May, June 2006) were determined at four locations along a ≈ 130 km long stretch of coast. Before the hurricanes, essential metals were likely limiting and concentrations of potentially toxic Pb were high in a contaminated lagoon (27.5 μg g(-1)) and near submarine springs (6.10 μg g(-1)); the likely sources were inland sewage disposal or excessive boat traffic. After the hurricanes, Pb decreased to 2.0 μg g(-1) in the contaminated lagoon probably through flushing. At the northern sites, essential Fe increased >2-fold (from 26.8 to 68.3 μg g(-1) on average), possibly from remobilization of anoxic sediments or upwelling of deep seawater during Wilma. Thus, hurricanes can be beneficial to seagrass beds in flushing toxic metals and replenishing essential elements. Copyright © 2011 Elsevier Ltd. All rights reserved.

  14. 78 FR 46999 - Additional Waivers and Alternative Requirements for Hurricane Sandy Grantees in Receipt of...

    Science.gov (United States)

    2013-08-02

    ... URBAN DEVELOPMENT Additional Waivers and Alternative Requirements for Hurricane Sandy Grantees in... impacted and distressed areas declared a major disaster due to Hurricane Sandy (see 78 FR 14329, published....) (Stafford Act), due to Hurricane Sandy and other eligible events in calendar years 2011, 2012, and 2013....

  15. 77 FR 74891 - Order Granting Exemptions From Certain Rules of Regulation SHO Related to Hurricane Sandy

    Science.gov (United States)

    2012-12-18

    ... COMMISSION Order Granting Exemptions From Certain Rules of Regulation SHO Related to Hurricane Sandy December 12, 2012. I. Introduction Hurricane Sandy made landfall along the mid-Atlantic Coast on October 29... in the Vault at the time Hurricane Sandy made landfall, facilitating DTCC's ability to...

  16. 78 FR 33467 - Second Allocation of Public Transportation Emergency Relief Funds in Response to Hurricane Sandy...

    Science.gov (United States)

    2013-06-04

    ... Response to Hurricane Sandy: Response, Recovery & Resiliency; Correction AGENCY: Federal Transit... by Hurricane Sandy. This amount was in addition to the initial $2 billion allocation announced in the... allocation restoration FTA Section 5324 Emergency Relief Program Allocations for Hurricane Sandy, by...

  17. Spatial Ecology of Puerto Rican Boas (Epicrates inornatus) in a Hurricane Impacted Forest.

    Science.gov (United States)

    Joseph M. Wunderle Jr.; Javier E. Mercado Bernard Parresol Esteban Terranova 2

    2004-01-01

    Spatial ecology of Puerto Rican boas (Epicrates inornatus, Boidae) was studied with radiotelemetry in a subtropical wet forest recovering from a major hurricane (7–9 yr previous) when Hurricane Georges struck. Different boas were studied during three periods relative to Hurricane Georges: before only; before and after; and after only. Mean daily movement per month...

  18. Hurricanes in the Gulf of Mexico and the Caribbean Sea and their relationship with sunspots

    Science.gov (United States)

    Rojo-Garibaldi, Berenice; Salas-de-León, David Alberto; Sánchez, Norma Leticia; Monreal-Gómez, María Adela

    2016-10-01

    We present the results of a time series analysis of hurricanes and sunspots occurring from 1749 to 2010. Exploratory analysis shows that the total number of hurricanes is declining. This decline is related to an increase in sunspot activity. Spectral analysis shows a relationship between hurricane oscillation periods and sunspot activity. Several sunspot cycles were identified from the time series analysis.

  19. Sediment Quality in Near Coastal Waters of the Gulf of Mexico: Influence of Hurricane Katrina

    Science.gov (United States)

    The results from this study represent a synoptic analysis of sediment quality in coastal waters of Lake Pontchartrain and Mississippi Sound two months after the landfall of Hurricane Katrina. Post-hurricane conditions were compared to pre-hurricane (2000-2004) conditions, for se...

  20. Trends in Serious Emotional Disturbance among Youths Exposed to Hurricane Katrina

    Science.gov (United States)

    McLaughlin, Katie A.; Fairbank, John A.; Gruber, Michael J.; Jones, Russell T.; Osofsky, Joy D.; Pfefferbaum, Betty; Sampson, Nancy A.; Kessler, Ronald C.

    2010-01-01

    Objective: To examine patterns and predictors of trends in "DSM-IV" serious emotional disturbance (SED) among youths exposed to Hurricane Katrina. Method: A probability sample of adult pre-hurricane residents of the areas affected by Katrina completed baseline and follow-up telephone surveys 18 to 27 months post-hurricane and 12 to 18…

  1. Serious Emotional Disturbance among Youths Exposed to Hurricane Katrina 2 Years Postdisaster

    Science.gov (United States)

    McLaughlin, Katie A.; Fairbank, John A.; Gruber, Michael J.; Jones, Russell T.; Lakoma, Matthew D.; Pfefferbaum, Betty; Sampson, Nancy A.; Kessler, Ronald C.

    2009-01-01

    Objective: To estimate the prevalence of serious emotional disturbance (SED) among children and adolescents exposed to Hurricane Katrina along with the associations of SED with hurricane-related stressors, sociodemographics, and family factors 18 to 27 months after the hurricane. Method: A probability sample of prehurricane residents of areas…

  2. Assessing a 1500-year record of Atlantic hurricane activity from South Andros Island, the Bahamas, using modeled hurricane climatology

    Science.gov (United States)

    Wallace, E. J.; Donnelly, J. P.; Emanuel, K.; Wiman, C.; van Hengstum, P. J.; Sullivan, R.; Winkler, T. S.

    2016-12-01

    Tropical cyclones can cause substantial loss of life and economic resources in coastal areas. In the current changing climate, it is of critical importance for society to understand any links between hurricane activity and climactic conditions. Unfortunately, historical tropical cyclone records are too short and incomplete to constrain how climate controls cyclone activity or to accurately quantify the risk of such storms to local human populations. Hurricane-induced deposits preserved in sediment cores can offer records of past hurricane activity stretching over thousands of years. Here we present a 1500 year annually resolved record of the frequency of intense hurricane events in a blue hole (AM4) on South Andros Island on the Great Bahama Bank. This carbonate island in the western North Atlantic Ocean is positioned along the trackway of many storms originating in the Caribbean and Atlantic basins. The record is corroborated by cores collected from three other blue holes near AM4. Over the past 1500 years, there have been periods of elevated hurricane activity from 750 to 950 CE, 1150 to 1300 CE and 1550 to 1850 CE. The statistical significance of this sedimentary record is assessed utilizing a set of synthetic storms generated from a previously published statistical deterministic hurricane model. The model simulates climatological conditions from the NCEP/NCAR reanalysis dataset, and the CMIP5 MPI model for the 20th century calibration (1850-2005 CE), and the millennial simulation (850-1849 CE). The average reoccurrence rates of hurricanes passing within 100 km of AM4 under each simulation are 1.06, 0.62, and 0.61 storms per year respectively. Using each climatology, thousands of hurricane induced deposits for the site are generated based on a random draw of these storms, a wind speed threshold for deposit, and a temporal resolution given the sedimentation rate of approximately 1 cm/yr at the site. Overall, the results of this study offer information on changes

  3. Did Hurricane Sandy influence the 2012 US presidential election?

    Science.gov (United States)

    Hart, Joshua

    2014-07-01

    Despite drawing on a common pool of data, observers of the 2012 presidential campaign came to different conclusions about whether, how, and to what extent "October surprise" Hurricane Sandy influenced the election. The present study used a mixed correlational and experimental design to assess the relation between, and effect of, the salience of Hurricane Sandy on attitudes and voting intentions regarding President Barack Obama and Mitt Romney in a large sample of voting-aged adults. Results suggest that immediately following positive news coverage of Obama's handling of the storm's aftermath, Sandy's salience positively influenced attitudes toward Obama, but that by election day, reminders of the hurricane became a drag instead of a boon for the President. In addition to theoretical implications, this study provides an example of how to combine methodological approaches to help answer questions about the impact of unpredictable, large-scale events as they unfold.

  4. Mold exposure and health effects following hurricanes Katrina and Rita.

    Science.gov (United States)

    Barbeau, Deborah N; Grimsley, L Faye; White, LuAnn E; El-Dahr, Jane M; Lichtveld, Maureen

    2010-01-01

    The extensive flooding in the aftermath of Hurricanes Katrina and Rita created conditions ideal for indoor mold growth, raising concerns about the possible adverse health effects associated with indoor mold exposure. Studies evaluating the levels of indoor and outdoor molds in the months following the hurricanes found high levels of mold growth. Homes with greater flood damage, especially those with >3 feet of indoor flooding, demonstrated higher levels of mold growth compared with homes with little or no flooding. Water intrusion due to roof damage was also associated with mold growth. However, no increase in the occurrence of adverse health outcomes has been observed in published reports to date. This article considers reasons why studies of mold exposure after the hurricane do not show a greater health impact.

  5. Nonlinear interaction of axisymmetric circulation and nonaxisymmetric disturbances in hurricanes

    Institute of Scientific and Technical Information of China (English)

    LUO Zhexian

    2004-01-01

    The nonlinear interaction of axisymmetric circulation and nonaxisymmetric disturbances in hurricanes is numerically studied with a quasigeostrophic barotropic model of a higher resolution. It is pointed out that the interaction may be divided into two categories. In the first category, nonaxisymmetric disturbances decay, the coordinate locus of maximum relative vorticity ζmax is seemingly unordered, and the central pressure of hurricane rises; while in the second one, nonaxisymmetric disturbances develop, the locus of ζmax shows an ordered limit cycle pattern, and the central pressure falls remarkably. A succinct criterion is given to judge which category the interaction belongs to, i.e. the vortex beta Rossby number at the initial time Rβ 1 to the developing one. Finally, practical applications of theoretical results of the rotational adaptation process presented by Zeng and numerical results in this paper to the hurricane intensity prediction in China are also discussed.

  6. Pet Ownership and Evacuation Prior to Hurricane Irene

    Directory of Open Access Journals (Sweden)

    Nick Rohrbaugh

    2012-09-01

    Full Text Available Pet ownership has historically been one of the biggest risk factors for evacuation failure prior to natural disasters. The forced abandonment of pets during Hurricane Katrina in 2005 made national headlines and led to the passage of the Pet Evacuation and Transportation Standards Act (PETS, 2006 which mandated local authorities to plan for companion animal evacuation. Hurricane Irene hit the East Coast of the United States in 2011, providing an excellent opportunity to examine the impact of the PETS legislation on frequency and ease of evacuation among pet owners and non-pet owners. Ninety pet owners and 27 non-pet owners who lived in mandatory evacuation zones completed questionnaires assessing their experiences during the hurricane and symptoms of depression, PTSD, dissociative experiences, and acute stress. Pet ownership was not found to be a statistical risk factor for evacuation failure. However, many pet owners who failed to evacuate continue to cite pet related reasons.

  7. Unique Meteorological Data During Hurricane Ike's Passage Over Houston

    Science.gov (United States)

    Schade, Gunnar; Rappenglück, Bernhard

    2009-06-01

    Hurricane Ike passed over the Houston, Tex., metropolitan area during the early morning of 13 September 2008. Although Ike had been rated only a category 2 on the Saffir-Simpson scale at landfall near Galveston, Tex., the storm's widespread damage to urban trees, many lacking proper trimming, knocked out the area's power distribution system; for some customers, power was only restored a month later. The hurricane's path after landfall (Figure 1a) went north through Galveston Bay and Baytown. The city of Houston—with its economically important ship channel—experienced the less severe western eye wall, the tight circulation with maximum wind speeds around the hurricane'ps center. The eye's passage was recorded between 3:00 and 4:30 A.M. Central Standard Time (CST; Figures 1a and 1c). It had maintained its unusually large diameter of 35-40 kilometers in its first hours after landfall.

  8. Anomalous Gulf Heating and Hurricane Katrinas Rapid Intensification

    CERN Document Server

    Kafatos, M; Gautam, R; Sun, Z B D; Cervone, Guido; Gautam, Ritesh; Kafatos, Menas; Sun, Zafer Boybeyi & Donglian

    2005-01-01

    Global warming due to the increasing concentration of greenhouse gases has become a great concern and has been linked to increased hurricane activity associated with higher sea surface temperatures with conflicting views. Our observational results based on long term trends of sea surface temperatures reveal that the anomaly reached a record 0.8 C in the Gulf of Mexico in August 2005 as compared to previous years and may have been responsible for the intensification of the devastating Hurricane Katrina into a category 5 hurricane that hit the Southern coast of United States severely impacting the low lying city of New Orleans and the surrounding areas. In most intensifying storms, air-sea interaction is the major contributing factor and here we show how air-sea interactions might have affected Katrinas rapid intensification in the Gulf.

  9. Two Empirical Models for Land-falling Hurricane Gust Factors

    Science.gov (United States)

    Merceret, Franics J.

    2008-01-01

    Gaussian and lognormal models for gust factors as a function of height and mean windspeed in land-falling hurricanes are presented. The models were empirically derived using data from 2004 hurricanes Frances and Jeanne and independently verified using data from 2005 hurricane Wilma. The data were collected from three wind towers at Kennedy Space Center and Cape Canaveral Air Force Station with instrumentation at multiple levels from 12 to 500 feet above ground level. An additional 200-foot tower was available for the verification. Mean wind speeds from 15 to 60 knots were included in the data. The models provide formulas for the mean and standard deviation of the gust factor given the mean windspeed and height above ground. These statistics may then be used to assess the probability of exceeding a specified peak wind threshold of operational significance given a specified mean wind speed.

  10. Longitudinal Impact of Hurricane Sandy Exposure on Mental Health Symptoms

    Directory of Open Access Journals (Sweden)

    Rebecca M. Schwartz

    2017-08-01

    Full Text Available Hurricane Sandy hit the eastern coast of the United States in October 2012, causing billions of dollars in damage and acute physical and mental health problems. The long-term mental health consequences of the storm and their predictors have not been studied. New York City and Long Island residents completed questionnaires regarding their initial Hurricane Sandy exposure and mental health symptoms at baseline and 1 year later (N = 130. There were statistically significant decreases in anxiety scores (mean difference = −0.33, p < 0.01 and post-traumatic stress disorder (PTSD scores (mean difference = −1.98, p = 0.001 between baseline and follow-up. Experiencing a combination of personal and property damage was positively associated with long-term PTSD symptoms (ORadj 1.2, 95% CI [1.1–1.4] but not with anxiety or depression. Having anxiety, depression, or PTSD at baseline was a significant predictor of persistent anxiety (ORadj 2.8 95% CI [1.1–6.8], depression (ORadj 7.4 95% CI [2.3–24.1 and PTSD (ORadj 4.1 95% CI [1.1–14.6] at follow-up. Exposure to Hurricane Sandy has an impact on PTSD symptoms that persists over time. Given the likelihood of more frequent and intense hurricanes due to climate change, future hurricane recovery efforts must consider the long-term effects of hurricane exposure on mental health, especially on PTSD, when providing appropriate assistance and treatment.

  11. The Hurricane-Flood-Landslide Continuum

    Science.gov (United States)

    Negri, Andrew J.; Burkardt, Nina; Golden, Joseph H.; Halverson, Jeffrey B.; Huffman, George J.; Larsen, Matthew C.; McGinley, John A.; Updike, Randall G.; Verdin, James P.; Wieczorek, Gerald F.

    2005-01-01

    In August 2004, representatives from NOAA, NASA, the USGS, and other government agencies convened in San Juan, Puerto Rim for a workshop to discuss a proposed research project called the Hurricane-Flood-Landslide Continuum (HFLC). The essence of the HFLC is to develop and integrate tools across disciplines to enable the issuance of regional guidance products for floods and landslides associated with major tropical rain systems, with sufficient lead time that local emergency managers can protect vulnerable populations and infrastructure. All three lead agencies are independently developing precipitation-flood-debris flow forecasting technologies, and all have a history of work on natural hazards both domestically and overseas. NOM has the capability to provide tracking and prediction of storm rainfall, trajectory and landfall and is developing flood probability and magnTtude capabilities. The USGS has the capability to evaluate the ambient stability of natural and man-made landforms, to assess landslide susceptibilities for those landforms, and to establish probabilities for initiation of landslides and debris flows. Additionally, the USGS has well-developed operational capacity for real-time monitoring and reporting of streamflow across distributed networks of automated gaging stations (http://water.usgs.gov/waterwatch/). NASA has the capability to provide sophisticated algorithms for satellite remote sensing of precipitation, land use, and in the future, soil moisture. The Workshop sought to initiate discussion among three agencies regarding their specific and highly complimentary capabilities. The fundamental goal of the Workshop was to establish a framework that will leverage the strengths of each agency. Once a prototype system is developed for example, in relatively data-rich Puerto Rim, it could be adapted for use in data-poor, low-infrastructure regions such as the Dominican Republic or Haiti. This paper provides an overview of the Workshop s goals

  12. Contribution of recent hurricanes to wetland sedimentation in coastal Louisiana

    Science.gov (United States)

    Liu, Kam-biu; Bianchette, Thomas; Zou, Lei; Qiang, Yi; Lam, Nina

    2017-04-01

    Hurricanes are important agents of sediment deposition in the wetlands of coastal Louisiana. Since Hurricanes Katrina and Rita of 2005, coastal Louisiana has been impacted by Hurricanes Gustav (2008), Ike (2008), and Isaac (2012). By employing the principles and methods of paleotempestology we have identified the storm deposits attributed to the three most recent hurricanes in several coastal lakes and swamps in Louisiana. However, the spatial distribution and volume of these storm depositions cannot be easily inferred from stratigraphic data derived from a few locations. Here we report on results from a GIS study to analyze the spatial and temporal patterns of storm deposition based on data extracted from the voluminous CRMS (Coastal Reference Monitoring System) database, which contains vertical accretion rate measurements obtained from 390 wetland sites over various time intervals during the past decade. Wetland accretion rates averaged about 2.89 cm/yr from stations sampled before Hurricane Isaac, 4.04 cm/yr during the 7-month period encompassing Isaac, and 2.38 cm/yr from sites established and sampled after Isaac. Generally, the wetland accretion rates attributable to the Isaac effects were 40% and 70% greater than before and after the event, respectively. Accretion rates associated with Isaac were highest at wetland sites along the Mississippi River and its tributaries instead of along the path of the hurricane, suggesting that freshwater flooding from fluvial channels, enhanced by the storm surge from the sea, is the main mechanism responsible for increased accretion in the wetlands. Our GIS work has recently been expanded to include other recent hurricanes. Preliminary results indicate that, for non-storm periods, the average wetland accretion rates between Katrina/Rita and Gustav/Ike was 2.58 cm/yr; that between Gustav/Ike and Isaac was 1.95 cm/yr; and that after Isaac was 2.37 cm/yr. In contrast, the accretion rates attributable to the effects of Gustav

  13. DRUG MARKET RECONSTITUTION AFTER HURRICANE KATRINA: LESSONS FOR LOCAL DRUG ABUSE CONTROL INITIATIVES

    Science.gov (United States)

    Bennett, Alex S.; Golub, Andrew; Dunlap, Eloise

    2011-01-01

    Hurricane Katrina accomplished what no law enforcement initiative could ever achieve: It completely eradicated the New Orleans drug market. However, Katrina did little to eliminate the demand for drugs. This article documents the process of the drug market reconstitution that occurred 2005–2008 based on in-depth interviews and focus groups with predominately low-income drug users and sellers. Before Katrina, the drug market was largely characterized by socially-bonded participants involved with corporate style distribution. After Katrina, a violent freelance market emerged. The conclusion draws recommendations for law enforcement for dealing with drug markets after a major disaster. This article uses New Orleans as a case study to chart the process of drug market reconstitution following an extreme disaster, namely Hurricane Katrina. On August 29, 2005, Hurricane Katrina made landfall and engulfed the New Orleans area, overwhelming levees and causing extensive flooding and destruction across the city. The storm generated 30- to 40-foot waves, which demolished many cities and small towns in Southern Mississippi and Alabama and caused considerable wind damage further inland. Although the hurricane eye missed central New Orleans by about 30 miles, the wave action in Lake Pontchartrain caused several levees to break and flood most of eastern New Orleans, which was under sea level. The storm had an impact on practically all New Orleans residents and almost destroyed New Orleans (Cooper & Block, 2006; Levitt & Whitaker, 2009; Lee, 2006). Our research focused on the impact of this storm on the drug markets in New Orleans. Katrina destroyed the physical environment and organizational structure that sustained the drug trade, yet drug use and sales did not disappear. During and soon after the storm, improvised sales and distribution organizations provided a wide range of illicit drugs to users (see Dunlap, Johnson, Kotarba, & Fackler, 2009; Dunlap & Golub, 2010; Dunlap

  14. DRUG MARKET RECONSTITUTION AFTER HURRICANE KATRINA: LESSONS FOR LOCAL DRUG ABUSE CONTROL INITIATIVES.

    Science.gov (United States)

    Bennett, Alex S; Golub, Andrew; Dunlap, Eloise

    2011-01-01

    Hurricane Katrina accomplished what no law enforcement initiative could ever achieve: It completely eradicated the New Orleans drug market. However, Katrina did little to eliminate the demand for drugs. This article documents the process of the drug market reconstitution that occurred 2005-2008 based on in-depth interviews and focus groups with predominately low-income drug users and sellers. Before Katrina, the drug market was largely characterized by socially-bonded participants involved with corporate style distribution. After Katrina, a violent freelance market emerged. The conclusion draws recommendations for law enforcement for dealing with drug markets after a major disaster.This article uses New Orleans as a case study to chart the process of drug market reconstitution following an extreme disaster, namely Hurricane Katrina. On August 29, 2005, Hurricane Katrina made landfall and engulfed the New Orleans area, overwhelming levees and causing extensive flooding and destruction across the city. The storm generated 30- to 40-foot waves, which demolished many cities and small towns in Southern Mississippi and Alabama and caused considerable wind damage further inland. Although the hurricane eye missed central New Orleans by about 30 miles, the wave action in Lake Pontchartrain caused several levees to break and flood most of eastern New Orleans, which was under sea level. The storm had an impact on practically all New Orleans residents and almost destroyed New Orleans (Cooper & Block, 2006; Levitt & Whitaker, 2009; Lee, 2006).Our research focused on the impact of this storm on the drug markets in New Orleans. Katrina destroyed the physical environment and organizational structure that sustained the drug trade, yet drug use and sales did not disappear. During and soon after the storm, improvised sales and distribution organizations provided a wide range of illicit drugs to users (see Dunlap, Johnson, Kotarba, & Fackler, 2009; Dunlap & Golub, 2010; Dunlap

  15. The Impact of Hurricane Katrina on the United States Tourism Industry

    Directory of Open Access Journals (Sweden)

    Nemanja Tomić

    2013-01-01

    Full Text Available The goal of this paper is to present hurricane Katrina in all its stages, from the beginning to the end and to highlight the economic, environmental and social consequences that occurred in the hurricane aftermath with a focus on the tourism industry. This paper also briefly explains the basic mechanism of tropical cyclones and hurricanes and their occurrences through a detailed explanation of hurricane Katrina and its effects on the United States. Some attention is also given to the immense damage and aftermath which is the largest ever made by any hurricane.

  16. [Hurricane impact on Thalassia testudinum (Hydrocharitaceae) beds in the Mexican Caribbean].

    Science.gov (United States)

    Arellano-Méndez, Leonardo U; Liceaga-Correa, María de los Angeles; Herrera-Silveira, Jorge A; Hernández-Núñez, Héctor

    2011-03-01

    Hurricanes have increased in strength and frequency as a result of global climate change. This research was conducted to study the spatio-temporal distribution and changes of Thalassia testudinum, the dominant species in Bahia de la Ascension (Quintana Roo, Mexico), when affected by heavy weather conditions. To complete this objective, a 2001 Landsat ETM+ image and the information from 525 sampling stations on morpho-functional and coverage of T. testudinum were used, and the seeds generated for the classification of eight benthic habitats. To quantify the changes caused by two hurricanes, we used two images, one of 1988 (Gilberto) and another of 1995 (Roxanne); other three data sets (2003, 2005 and 2007) were also used to describe the study area without major weather effects. Six categorial maps were obtained and subjected to analysis by 8 Landscape Ecology indexes, that describe the spatial characteristics, structure, function, change of the elements (matrix-patch-corridor), effects on ecosystems, connectivity, edges, shape and patch habitat fragmentation. Models indicate that T. testudinum may be classified as a continuum (matrix), since the fragments were not observed intermittently, but as a progression from minimum to maximum areas in reference to their coverage (ecological corridors). The fragments do not have a regular shape, indicating that the impacts are recent and may be due to direct effects (high-intensity hurricanes) or indirect (sediment). Fragments of type "bare soils" have a discontinuous distribution, and are considered to be the sites that have remained stable over a long timescale. While more dense coverage areas ("beds", "medium prairie" and "prairie") have low fragmentation and high connection of fragments. Features have an irregular perimeter and radial growth of formal; suggesting that the impact of meteors has no effect on the resilience of T. testudinum in this ecosystem, indicating good environmental quality to grow in this bay.

  17. Lipopolysaccharide Structure and Biosynthesis in Helicobacter pylori.

    Science.gov (United States)

    Li, Hong; Liao, Tingting; Debowski, Aleksandra W; Tang, Hong; Nilsson, Hans-Olof; Stubbs, Keith A; Marshall, Barry J; Benghezal, Mohammed

    2016-12-01

    This review covers the current knowledge and gaps in Helicobacter pylori lipopolysaccharide (LPS) structure and biosynthesis. H. pylori is a Gram-negative bacterium which colonizes the luminal surface of the human gastric epithelium. Both a constitutive alteration of the lipid A preventing TLR4 elicitation and host mimicry of the Lewis antigen decorated O-antigen of H. pylori LPS promote immune escape and chronic infection. To date, the complete structure of H. pylori LPS is not available, and the proposed model is a linear arrangement composed of the inner core defined as the hexa-saccharide (Kdo-LD-Hep-LD-Hep-DD-Hep-Gal-Glc), the outer core composed of a conserved trisaccharide (-GlcNAc-Fuc-DD-Hep-) linked to the third heptose of the inner core, the glucan, the heptan and a variable O-antigen, generally consisting of a poly-LacNAc decorated with Lewis antigens. Although the glycosyltransferases (GTs) responsible for the biosynthesis of the H. pylori O-antigen chains have been identified and characterized, there are many gaps in regard to the biosynthesis of the core LPS. These limitations warrant additional mutagenesis and structural studies to obtain the complete LPS structure and corresponding biosynthetic pathway of this important gastric bacterium.

  18. Mental health outcomes at the Jersey Shore after Hurricane Sandy.

    Science.gov (United States)

    Boscarino, Joseph A; Hoffman, Stuart N; Kirchner, H Lester; Erlich, Porat M; Adams, Richard E; Figley, Charles R; Solhkhah, Ramon

    2013-01-01

    On October 29, 2012, Hurricane Sandy made landfall in the most densely populated region in the US. In New Jersey, thousands of families were made homeless and entire communities were destroyed in the worst disaster in the history of the state. The economic impact of Sandy was huge, comparable to Hurricane Katrina. The areas that sustained the most damage were the small- to medium-sized beach communities along New Jersey's Atlantic coastline. Six months following the hurricane, we conducted a random telephone survey of 200 adults residing in 18 beach communities located in Monmouth County. We found that 14.5% (95% CI = 9.9-20.2) of these residents screened positive for PTSD and 6.0% (95% CI = 3.1-10.2) met criteria for major depression. Altogether 13.5% (95% CI = 9.1-19.0) received mental health counseling and 20.5% (95% CI = 15.1-26.8) sought some type of mental health support in person or online, rates similar to those reported in New York after the World Trade Center disaster In multivariate analyses, the best predictors of mental health status and service use were having high hurricane exposure levels, having physical health limitations, and having environmental health concerns. Research is needed to assess the mental health status and service use of Jersey Shore residents over time, to evaluate environmental health concerns, and to better understand the storm's impact among those with physical health limitations.

  19. Hurricane Sandy: An Educational Bibliography of Key Research Studies

    Science.gov (United States)

    Piotrowski, Chris

    2013-01-01

    There, undoubtedly, will be a flurry of research activity in the "Superstorm" Sandy impact area on a myriad of disaster-related topics, across academic disciplines. The purpose of this study was to review the disaster research related specifically to hurricanes in the educational and social sciences that would best serve as a compendium…

  20. Tornadoes & Hurricanes. The Natural Disaster Series. Grades 4-8.

    Science.gov (United States)

    Deery, Ruth

    The topics of tornadoes and hurricanes are important to children but are often missing from elementary textbooks. This document is a part of "The Natural Disaster Series" and is an attempt to supplement elementary science and social studies programs with lessons and student activities. Reasoning skills are emphasized throughout the…

  1. Quantifying the hurricane catastrophe risk to offshore wind power.

    Science.gov (United States)

    Rose, Stephen; Jaramillo, Paulina; Small, Mitchell J; Apt, Jay

    2013-12-01

    The U.S. Department of Energy has estimated that over 50 GW of offshore wind power will be required for the United States to generate 20% of its electricity from wind. Developers are actively planning offshore wind farms along the U.S. Atlantic and Gulf coasts and several leases have been signed for offshore sites. These planned projects are in areas that are sometimes struck by hurricanes. We present a method to estimate the catastrophe risk to offshore wind power using simulated hurricanes. Using this method, we estimate the fraction of offshore wind power simultaneously offline and the cumulative damage in a region. In Texas, the most vulnerable region we studied, 10% of offshore wind power could be offline simultaneously because of hurricane damage with a 100-year return period and 6% could be destroyed in any 10-year period. We also estimate the risks to single wind farms in four representative locations; we find the risks are significant but lower than those estimated in previously published results. Much of the hurricane risk to offshore wind turbines can be mitigated by designing turbines for higher maximum wind speeds, ensuring that turbine nacelles can turn quickly to track the wind direction even when grid power is lost, and building in areas with lower risk.

  2. Calibration of Hurricane Imaging Radiometer C-Band Receivers

    Science.gov (United States)

    Biswas, Sayak K.; Cecil, Daniel J.; James, Mark W.

    2017-01-01

    The laboratory calibration of airborne Hurricane Imaging Radiometer's C-Band multi-frequency receivers is described here. The method used to obtain the values of receiver frontend loss, internal cold load brightness temperature and injected noise diode temperature is presented along with the expected RMS uncertainty in the final calibration.

  3. Hurricane-induced failure of low salinity wetlands

    Science.gov (United States)

    Howes, Nick C.; FitzGerald, Duncan M.; Hughes, Zoe J.; Georgiou, Ioannis Y.; Kulp, Mark A.; Miner, Michael D.; Smith, Jane M.; Barras, John A.

    2010-01-01

    During the 2005 hurricane season, the storm surge and wave field associated with Hurricanes Katrina and Rita eroded 527 km2 of wetlands within the Louisiana coastal plain. Low salinity wetlands were preferentially eroded, while higher salinity wetlands remained robust and largely unchanged. Here we highlight geotechnical differences between the soil profiles of high and low salinity regimes, which are controlled by vegetation and result in differential erosion. In low salinity wetlands, a weak zone (shear strength 500–1450 Pa) was observed ∼30 cm below the marsh surface, coinciding with the base of rooting. High salinity wetlands had no such zone (shear strengths > 4500 Pa) and contained deeper rooting. Storm waves during Hurricane Katrina produced shear stresses between 425–3600 Pa, sufficient to cause widespread erosion of the low salinity wetlands. Vegetation in low salinity marshes is subject to shallower rooting and is susceptible to erosion during large magnitude storms; these conditions may be exacerbated by low inorganic sediment content and high nutrient inputs. The dramatic difference in resiliency of fresh versus more saline marshes suggests that the introduction of freshwater to marshes as part of restoration efforts may therefore weaken existing wetlands rendering them vulnerable to hurricanes. PMID:20660777

  4. SIMULATING LAKE PONTCHARTRAIN AND MISSISSIPPI RIVER OUTFLOW AFTER HURRICANE KATRINA

    Science.gov (United States)

    Hurricane Katrina was the direct cause of the flooding of New Orleans in September 2005. Between its passage and the pumping of flood waters back into Lake Pontchartrain and the Mississippi River, the flood waters acquired considerable amounts of contaminants, notably silver, but...

  5. Hurricane Katrina winds damaged longleaf pine less than loblolly pine

    Science.gov (United States)

    Kurt H. Johnsen; John R. Butnor; John S. Kush; Ronald C. Schmidtling; C. Dana. Nelson

    2009-01-01

    Some evidence suggests that longleaf pine might be more tolerant of high winds than either slash pine (Pinus elliotii Englem.) or loblolly pine (Pinus taeda L.). We studied wind damage to these three pine species in a common garden experiment in southeast Mississippi following Hurricane Katrina,...

  6. Gone with the Wind? Integrity and Hurricane Katrina

    Science.gov (United States)

    Lucas, Frances; Katz, Brit

    2011-01-01

    Hurricane Katrina slammed into 80 miles of Mississippi shoreline on August 29, 2005. It was the nation's worst natural disaster, a perfect storm. One hundred sixty miles-per-hour winds sent 55-foot-tall waves and a 30-foot wall of water across the shore and miles inland. It displaced 400,000 residents along the coast of the Mississippi, and…

  7. Stress and Support in Family Relationships after Hurricane Katrina

    Science.gov (United States)

    Reid, Megan; Reczek, Corinne

    2011-01-01

    In this article, the authors merge the study of support, strain, and ambivalence in family relationships with the study of stress to explore the ways family members provide support or contribute to strain in the disaster recovery process. The authors analyze interviews with 71 displaced Hurricane Katrina survivors, and identify three family…

  8. Breakup of New Orleans Households after Hurricane Katrina

    Science.gov (United States)

    Rendall, Michael S.

    2011-01-01

    Theory and evidence on disaster-induced population displacement have focused on individual and population-subgroup characteristics. Less is known about impacts on households. I estimate excess incidence of household breakup resulting from Hurricane Katrina by comparing a probability sample of pre-Katrina New Orleans resident adult household heads…

  9. 48 CFR 1852.236-73 - Hurricane plan.

    Science.gov (United States)

    2010-10-01

    ... event of a hurricane warning, the Contractor shall— (a) Inspect the area and place all materials possible in a protected location; (b) Tie down, or identify and store, all outside equipment and materials; (c) Clear all surrounding areas and roofs of buildings, or tie down loose material, equipment,...

  10. Staying Safe in Your Home During a Hurricane

    Centers for Disease Control (CDC) Podcasts

    2006-08-10

    If you are not ordered to evacuate, and you stay in your home through a hurricane, there are things you can do to protect yourself and your family.  Created: 8/10/2006 by Emergency Communications System.   Date Released: 8/13/2008.

  11. Impact of Targeted Ocean Observations for Improving Ocean Model Initialization for Coupled Hurricane Forecasting

    Science.gov (United States)

    Halliwell, G. R.; Srinivasan, A.; Kourafalou, V. H.; Yang, H.; Le Henaff, M.; Atlas, R. M.

    2012-12-01

    Horizon oil spill. OSSE evaluation and calibration is then performed by repeating these two OSEs with synthetic observations and comparing the resulting observing system impact to determine if it differs from the OSE results. OSSEs are first run to evaluate different airborne sampling strategies with respect to temporal frequency of flights and the horizontal separation of upper-ocean profiles during each flight. They are then run to assess the impact of releasing multiple floats and gliders. Evaluation strategy focuses on error reduction in fields important for hurricane forecasting such as the structure of ocean currents and eddies, upper ocean heat content distribution, and upper-ocean stratification.

  12. On the Use of Coupled Wind, Wave, and Current Fields in the Simulation of Loads on Bottom-Supported Offshore Wind Turbines during Hurricanes: March 2012 - September 2015

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Eungsoo [Univ. of Texas, Austin, TX (United States); Manuel, Lance [Univ. of Texas, Austin, TX (United States); Curcic, Milan [Univ. of Miami, Coral Gables, FL (United States); Chen, Shuyi S. [Univ. of Miami, Coral Gables, FL (United States); Phillips, Caleb [National Renewable Energy Lab. (NREL), Golden, CO (United States); Veers, Paul [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-06-01

    , and soil-structure interaction effects. A detailed framework is presented that explains how coupled inputs can be included in turbine loads studies during a hurricane. This framework can aid in future efforts aimed at developing offshore wind turbine design criteria and load cases related to hurricanes.

  13. Climatology of landfalling hurricanes and tropical storms in Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Jauregui, E. [Centro de Ciencias de la Atmosfera, Universidad Nacional Autonoma de Mexico (UNAM), Mexico, D.F. (Mexico)

    2003-10-01

    The potential for damage from hurricanes landfalling in Mexico is assessed. During the 1951-2000 period, Pacific hurricane hits were more frequent on coastal areas of the northwest of country (e.g., Sinaloa and the southern half of Baja California Peninsula) as well as in southern Mexico (Michoacan). On the Atlantic side, the Yucatan Peninsula and the northern state of Tamaulipas were most exposed to these storms. The hurricane season reaches maximum activity in September for both the Atlantic and Pacific coasts of the country. During the 50 year period, five intense hurricanes (category 5) made landfall on the Gulf/Caribbean coasts, while only one such intense hurricane made a land hit on the Pacific side. While hurricanes affecting Pacific coasts show a marked increase during the last decade, those of the Atlantic side exhibit a marked decrease since the 1970s. However, when considering the frequency of landfalling tropical storms and hurricanes impacting on both littorals of the country, their numbers have considerably increased during the 1990s. [Spanish] Se determino el potencial de dano de los huracanes que entran a tierra en Mexico. Durante el periodo 1951-2000 los impactos de los huracanes del Pacifico fueron mas frecuentes en las areas costeras del noroeste del pais, como Sinaloa y la mitad sur de la peninsula de Baja California, asi como en el sur de Mexico (Michoacan). En el lado del Atlantico la peninsula de Yucatan y el estado norteno de Tamaulipas fueron los mas expuestos a estas tormentas. Para las dos costas del pais, del Pacifico y del Atlantico, la temporada de huracanes alcanza su maxima actividad en septiembre. Durante los 50 anos del periodo de estudio cinco huracanes intensos (categoria 5) tocaron tierra en el lado del Atlantico y uno en el Pacifico. Mientras que los huracanes que afectan las costas del Pacifico muestran un incremento en numero durante la ultima decada, los del Atlantico exhiben una disminucion notable desde la decada de los

  14. Turbulent flow over a house in a simulated hurricane boundary layer

    CERN Document Server

    Taylor, Zachary; Gurka, Roi; Kopp, Gregory

    2009-01-01

    Every year hurricanes and other extreme wind storms cause billions of dollars in damage worldwide. For residential construction, such failures are usually associated with roofs, which see the largest aerodynamic loading. However, determining aerodynamic loads on different portions of North American houses is complicated by the lack of clear load paths and non-linear load sharing in wood frame roofs. This problem of fluid-structure interaction requires both wind tunnel testing and full-scale structural testing. A series of wind tunnel tests have been performed on a house in a simulated atmospheric boundary layer (ABL), with the resulting wind-induced pressures applied to the full-scale structure. The ABL was simulated for flow over open country terrain where both velocity and turbulence intensity profiles, as well as spectra, were matched with available full scale measurements for this type of terrain. The first set of measurements was 600 simultaneous surface pressure measurements over the entire house. A key...

  15. Quantifying human mobility perturbation and resilience in Hurricane Sandy.

    Science.gov (United States)

    Wang, Qi; Taylor, John E

    2014-01-01

    Human mobility is influenced by environmental change and natural disasters. Researchers have used trip distance distribution, radius of gyration of movements, and individuals' visited locations to understand and capture human mobility patterns and trajectories. However, our knowledge of human movements during natural disasters is limited owing to both a lack of empirical data and the low precision of available data. Here, we studied human mobility using high-resolution movement data from individuals in New York City during and for several days after Hurricane Sandy in 2012. We found the human movements followed truncated power-law distributions during and after Hurricane Sandy, although the β value was noticeably larger during the first 24 hours after the storm struck. Also, we examined two parameters: the center of mass and the radius of gyration of each individual's movements. We found that their values during perturbation states and steady states are highly correlated, suggesting human mobility data obtained in steady states can possibly predict the perturbation state. Our results demonstrate that human movement trajectories experienced significant perturbations during hurricanes, but also exhibited high resilience. We expect the study will stimulate future research on the perturbation and inherent resilience of human mobility under the influence of hurricanes. For example, mobility patterns in coastal urban areas could be examined as hurricanes approach, gain or dissipate in strength, and as the path of the storm changes. Understanding nuances of human mobility under the influence of such disasters will enable more effective evacuation, emergency response planning and development of strategies and policies to reduce fatality, injury, and economic loss.

  16. Lightning and radar observations of hurricane Rita landfall

    Energy Technology Data Exchange (ETDEWEB)

    Henderson, Bradley G [Los Alamos National Laboratory; Suszcynsky, David M [Los Alamos National Laboratory; Hamlin, Timothy E [Los Alamos National Laboratory; Jeffery, C A [Los Alamos National Laboratory; Wiens, Kyle C [TEXAS TECH U.; Orville, R E [TEXAS A& M

    2009-01-01

    Los Alamos National Laboratory (LANL) owns and operates an array of Very-Low Frequency (VLF) sensors that measure the Radio-Frequency (RF) waveforms emitted by Cloud-to-Ground (CG) and InCloud (IC) lightning. This array, the Los Alamos Sferic Array (LASA), has approximately 15 sensors concentrated in the Great Plains and Florida, which detect electric field changes in a bandwidth from 200 Hz to 500 kHz (Smith et al., 2002). Recently, LANL has begun development of a new dual-band RF sensor array that includes the Very-High Frequency (VHF) band as well as the VLF. Whereas VLF lightning emissions can be used to deduce physical parameters such as lightning type and peak current, VHF emissions can be used to perform precise 3d mapping of individual radiation sources, which can number in the thousands for a typical CG flash. These new dual-band sensors will be used to monitor lightning activity in hurricanes in an effort to better predict intensification cycles. Although the new LANL dual-band array is not yet operational, we have begun initial work utilizing both VLF and VHF lightning data to monitor hurricane evolution. In this paper, we present the temporal evolution of Rita's landfall using VLF and VHF lightning data, and also WSR-88D radar. At landfall, Rita's northern eyewall experienced strong updrafts and significant lightning activity that appear to mark a transition between oceanic hurricane dynamics and continental thunderstorm dynamics. In section 2, we give a brief overview of Hurricane Rita, including its development as a hurricane and its lightning history. In the following section, we present WSR-88D data of Rita's landfall, including reflectivity images and temporal variation. In section 4, we present both VHF and VLF lightning data, overplotted on radar reflectivity images. Finally, we discuss our observations, including a comparison to previous studies and a brief conclusion.

  17. Quantifying human mobility perturbation and resilience in Hurricane Sandy.

    Directory of Open Access Journals (Sweden)

    Qi Wang

    Full Text Available Human mobility is influenced by environmental change and natural disasters. Researchers have used trip distance distribution, radius of gyration of movements, and individuals' visited locations to understand and capture human mobility patterns and trajectories. However, our knowledge of human movements during natural disasters is limited owing to both a lack of empirical data and the low precision of available data. Here, we studied human mobility using high-resolution movement data from individuals in New York City during and for several days after Hurricane Sandy in 2012. We found the human movements followed truncated power-law distributions during and after Hurricane Sandy, although the β value was noticeably larger during the first 24 hours after the storm struck. Also, we examined two parameters: the center of mass and the radius of gyration of each individual's movements. We found that their values during perturbation states and steady states are highly correlated, suggesting human mobility data obtained in steady states can possibly predict the perturbation state. Our results demonstrate that human movement trajectories experienced significant perturbations during hurricanes, but also exhibited high resilience. We expect the study will stimulate future research on the perturbation and inherent resilience of human mobility under the influence of hurricanes. For example, mobility patterns in coastal urban areas could be examined as hurricanes approach, gain or dissipate in strength, and as the path of the storm changes. Understanding nuances of human mobility under the influence of such disasters will enable more effective evacuation, emergency response planning and development of strategies and policies to reduce fatality, injury, and economic loss.

  18. Linking soils and streams: Response of soil solution chemistry to simulated hurricane disturbance mirrors stream chemistry following a severe hurricane

    Science.gov (United States)

    William H. McDowell; Daniel Liptzin

    2014-01-01

    Understanding the drivers of forest ecosystem response to major disturbance events is an important topic in forest ecology and ecosystem management. Because of the multiple elements included in most major disturbances such as hurricanes, fires, or landslides, it is often difficult to ascribe a specific driver to the observed response. This is particularly true for the...

  19. Mother and Child Reports of Hurricane Related Stressors: Data from a Sample of Families Exposed to Hurricane Katrina

    Science.gov (United States)

    Lai, Betty S.; Beaulieu, Brooke; Ogokeh, Constance E.; Self-Brown, Shannon; Kelley, Mary Lou

    2015-01-01

    Background: Families exposed to disasters such as Hurricane Katrina are at risk for numerous adverse outcomes. While previous literature suggests that the degree of disaster exposure corresponds with experiencing negative outcomes, it is unclear if parents and children report similar levels of disaster exposure. Objective: The purpose of this…

  20. Combined effects of Hurricane Katrina and Hurricane Gustav on the mental health of mothers of small children.

    Science.gov (United States)

    Harville, E W; Xiong, X; Smith, B W; Pridjian, G; Elkind-Hirsch, K; Buekens, P

    2011-05-01

    Few studies have assessed the results of multiple exposures to disaster. Our objective was to examine the effect of experiencing Hurricane Gustav on mental health of women previously exposed to Hurricane Katrina. A total of 102 women from Southern Louisiana were interviewed by telephone. Experience of the hurricanes was assessed with questions about injury, danger and damage, while depression was assessed with the Edinburgh Depression Scale and post-traumatic stress disorder using the Post-Traumatic Checklist. Minor stressors, social support, trait resilience and perceived benefit had been measured previously. Mental health was examined with linear and log-linear models. Women who had a severe experience of both Gustav and Katrina scored higher on the mental health scales, but finding new ways to cope after Katrina or feeling more prepared was not protective. About half the population had better mental health scores after Gustav than at previous measures. Improvement was more likely among those who reported high social support or low levels of minor stressors, or were younger. Trait resilience mitigated the effect of hurricane exposure. Multiple disaster experiences are associated with worse mental health overall, although many women are resilient. Perceiving benefit after the first disaster was not protective. © 2010 Blackwell Publishing.