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Sample records for abnormal storm waves

  1. [Transient abnormal Q-waves].

    PubMed

    Godballe, C; Hoeck, H C; Sørensen, J A

    1990-01-01

    We present a case of transient abnormal Q-waves (TAQ) and a review of the literature. TAQ are defined as abnormal Q-waves, which disappear within ten days. They are most often seen in patients with ischemic heart disease (IHD) but are also seen in other conditions. Brief episodes of myocardial ischemia giving rise to reversible biochemical and ultrastructural myocardial changes, resulting in transient ECG changes, provide an accepted theory for the pathogenesis of TAO. Investigations have shown that the occurrence of exercise-induced TAQ may be a symptom of IHD. It is impossible to distinguish TAQ from Q-waves induced by myocardial infarction. Appearance of TAQ during exercise-testing frequently indicates IHD. PMID:2301045

  2. Electrocardiography series. Electrocardiographic T wave abnormalities.

    PubMed

    Lin, Weiqin; Teo, Swee Guan; Poh, Kian Keong

    2013-11-01

    The causes of abnormal T waves on electrocardiography are multiple and varied. Careful clinical history taking and physical examination are necessary for accurate identification of the cause of such abnormalities. Subsequent targeted specialised cardiac investigations, such as echocardiography or coronary angiography, may be of importance in the diagnosis of the underlying cardiac pathology. We present two cases of T wave inversions with markedly different aetiologies.

  3. Intractable Electrical Storm After Coronary Artery Bypass Grafting Originating in Abnormal Purkinje Fibers.

    PubMed

    Tokunaga, Chiho; Tsukada, Toru; Sakamoto, Hiroaki; Naruse, Yoshihisa; Yoshida, Kentaro; Sekiguchi, Yukio; Imai, Akito; Aonuma, Kazutaka; Hiramatsu, Yuji

    2016-01-01

    Electrical storm is a rare but critical complication following revascularization in patients with ischemic heart disease. We report the case of a 67-year-old man who developed drug refractory intractable electrical storm after emergent coronary artery bypass grafting for ischemic cardiomyopathy. The electrical storm was successfully eliminated by percutaneous endocardial radiofrequency catheter ablation targeting the abnormal Purkinje-related triggering ventricular premature contractions in a low-voltage zone.

  4. Geomagnetic Storms and EMIC waves: Van Allen Probe observations

    NASA Astrophysics Data System (ADS)

    Wang, D.; Yuan, Z.; Yu, X.; Deng, X.; Zhou, M.; Huang, S.; Li, H.

    2015-12-01

    EMIC waves are believed to play an important role in the dynamics of ring current ions and radiation belt electrons, especially during geomagnetic storms. But, in which phase of the storm do the EMIC waves occur more is still under debate. Ground and some low altitude satellite observations demonstrate that EMIC waves are observed more frequently during the recovery phase, rather than during the main phase. Halford et al. 2010 looked at the occurrences of EMIC waves during 119 storms occurring throughout the CRRES mission. They found that 49 of the 119 (41%) storms observed EMIC waves and the majority, 56.25%, of storm time EMIC waves occurring during the main phase, while 35.57% in the recovery phase. One shortcoming of the CRRES mission is that the apogee of it did not covered the dawn to noon sector during its life time. Therefore, some dayside EMIC waves caused by the compression of magnetosphere may not be included in Halford et al 2010, as they mentioned. The apogee of Van Allen Probes covered all the MLT sectors from their launch to April 2014. Utilizing the data from magnetometer instrument on board the Van Allen Probe A, Wang et al. 2015 studied the occurrence rate of H-band and He-band EMIC waves in different MLT sectors, and Yu et al 2015 reported the O-band EMIC wave observations. In this work, we analysis the occurrence of EMIC waves during storms. According to the criteria of storm in Halford et al. 2010, we find 76 storms in our interested period, 8 September 2012 to 30 April 2014, when the apogee of Van Allen Probe A covered all the MLT sectors. To identify the onset of geomagnetic storm more accurately, we corrected the Sym-H index referred to Zhao and Zong (2011), which is helpful to demonstrate the activity of ring current. 50 of the 76 storms (66%) observed 124 EMIC wave events, in which 80 (64.5%) EMIC wave events are found in the recovery phase, more than the EMIC wave events in the main phase (35, 28.2%). The remaining 9 (7.3%) EMIC wave

  5. Are certain storms overestimated in the NORA10 wave hindcast?

    NASA Astrophysics Data System (ADS)

    Furevik, Birgitte; Röhrs, Johannes Johannes; Carrasco, Ana; Engedahl, Harald; Reistad, Magnar

    2015-04-01

    The Norwegian Reanalysis of wind and waves (NORA10) is a downscaling to 10 km of the ERA-40 dataset and ECMWF forecasts for 1958-2014. The significant wave height (Hs) in some storms in 2006 and 2011 are modelled 13-23% higher than observed even if modelled winds seem to be in accordance with observations. The propagation track and speed of these storms and possible swell into the area is investigated compared to similar situations. The wave observations from the storms are analyzed as well as data from experiments using SWAN with different dissipation formulations and two different versions of WAM. One is WAM cycle 4 from 1998 (modified for parallel processing and rotated grid) running operationally at MET and the other is a new version made available through the MyWave project. Preliminary studies show that MyWave WAM gives higher waves than the old version of WAM in the storms mentioned while SWAN with Westhuysen dissipation gives values of Hs closest to the observed. A new operational wave model setup using MyWave WAM on 4km spatial resolution over a domain covering the Nordic Seas is implemented and considered for operational use. The performance of the new wave model setup for the Nordic Seas is validated against the offshore observations and compared to the existing forecasting system.

  6. Modeling Motu Profile Response to Varying Wave and Storm Climate

    NASA Astrophysics Data System (ADS)

    Ortiz, A. C.; Ashton, A. D.; Donnelly, J. P.

    2014-12-01

    The atolls of the Pacific Ocean are low-lying landforms (less than 5m in elevation), typically consisting of reef-building corals often mounted by subaerial islets, or motu, which encircle a central lagoon. These motu, perched atop old coral reefs, typically consist of sand and gravel, and are sometimes anchored by relict geologic features (highstand coral reefs). Despite the vital role these islets play as home to terrestrial ecosystems and human infrastructure, the morphologic processes responsible for their formation and maintenance remain poorly understood. For example, although extreme events are hypothesized as a formation mechanism, motu are found in regions where hurricanes or tropical cyclones rarely occur and across varying storm gradients and frequency tracks. Here we use hydrodynamic and event-based morphodynamic modeling to better understand the role of storm events on the formation and evolution of motu. Using XBeach, a two-dimensional model of infragravity wave propagation and sediment transport, coupled with the coastal wave model, SWAN (Simulating WAves Nearshore), we simulate the hydrodynamic and morphodynamic impacts of storm events on the nearshore, beach, and backbarrier portions of atolls. We investigate the effect of different representative profile morphology, for example motu height or the distance from the reef edge to the motu, on storm response. We further test the effect of storm intensity and inundation scenarios (i.e. difference in elevated water levels of the lagoon and ocean) on storm hydrodynamics and morphologic change. Model scenarios are informed and compared to basin-wide analysis of the variation of atoll and motu characteristics, such as reef width, motu width, and motu spacing across the Pacific Ocean. Atoll morphologies and storm responses are affected by both geographic location and, locally, the shoreline orientation (compared to storm tracks). Combining these different model scenarios with measured morphometrics allows

  7. In-Situ Severe Storm Monitoring Utilizing the Wave Glider

    NASA Astrophysics Data System (ADS)

    Griffith, J.; Thomas, J.

    2013-12-01

    The Wave Glider (WG) is an ocean going Unmanned Surface Vehicle (USV) that harnesses mechanical energy from waves and electrical energy from solar cells to power a configurable panel of scientific instruments. With its ability to transmit sensor data to shore in near real-time via an Iridium satellite connection, the Wave Glider can be used as a remote, mobile data collection platform on the world's oceans for extended periods up to a year. In a series of trials and demonstrations, the vehicle was directed into the path of 2 hurricanes, a cyclone, and a tropical storm while transmitting oceanographic and meteorological data including wind speed, wind direction, barometric pressure, sea surface temperature and wave height. In its transit through Tropical Cyclone Freda, for example, the Wave Glider measured barometric pressure as low as 975 millibar and significant wave heights of up to 9 meters. Data from these 4 events exhibit strong correlation with independent data products such as ASCAT and NOAA's JTWC-WaveWatch III model. In all 4 events, the Wave Glider provided uninterrupted data streams in near-real time despite the extreme conditions. These data collections are solid evidence that the Wave Glider is a suitable and highly efficient platform for the observation of sea surface and lower atmospheric conditions from directly within severe storm events.

  8. Movement of boulders and megagravel by storm waves

    NASA Astrophysics Data System (ADS)

    Cox, Rónadh; Jahn, Kalle L.; Watkins, Oona G.

    2016-04-01

    Coastal boulder deposits along Ireland's west coast - which include megagravel with masses in the 100s of tonnes near sea level, and boulders > 1 t at locations up to 50 m above high water (AHW) - record extreme wave events. As their scale and elevation seem inconsistent with our current understanding of storm wave hydrodynamics, and because the deposits have been largely inactive in the last decade or so (the time span over which they have been studied), there has been controversy over whether they are moved by storms or whether they are relict tsunami deposits. Recent data acquisition shows definitively that these rocks are moved during storms. Using repeat photography of sites on the Aran Islands and on the mainland (images taken before and after the severe storms of winter 2013-2014) we documented movement of >1100 clasts, 84 of which were ≥ 20 t, and 16 of which were ≥ 50 t. The highest elevation at which we recorded movement was 25 m AHW, and the largest clast moved at this elevation was ~5.5 t. Larger clasts (up to ~400 t) moved at lower elevations. Horizontal transport distances exceeded 100 m in some instances, including large dislocations of some very large clasts (e.g. a ~210 t block that moved 23 m inland). The large dataset allows us to investigate relationships between clast movements and topography. For each site, the largest clast moved represents an upper limit on the transport capacity at that site (for that set of storms). We find an inverse correlation between mass transported and height above high water, as well as a (counter-intuitive) positive correlation between boulder mass and distance inland. The strongest correlation, however, is an exponential relationship between mass and average coastal slope: the largest clasts moved over the most gently sloping terrain. We use the term "waves" quite loosely. The clasts were transported by overland flow of ocean waters activated by storm systems, but we cannot determine whether the flow was due

  9. Rapid Response Measurements of Hurricane Waves and Storm Surge

    NASA Astrophysics Data System (ADS)

    Gravois, U.

    2010-12-01

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

  10. Effects of abnormal excitation on the dynamics of spiral waves

    NASA Astrophysics Data System (ADS)

    Min-Yi, Deng; Xue-Liang, Zhang; Jing-Yu, Dai

    2016-01-01

    The effect of physiological and pathological abnormal excitation of a myocyte on the spiral waves is investigated based on the cellular automaton model. When the excitability of the medium is high enough, the physiological abnormal excitation causes the spiral wave to meander irregularly and slowly. When the excitability of the medium is low enough, the physiological abnormal excitation leads to a new stable spiral wave. On the other hand, the pathological abnormal excitation destroys the spiral wave and results in the spatiotemporal chaos, which agrees with the clinical conclusion that the early after depolarization is the pro-arrhythmic mechanism of some anti-arrhythmic drugs. The mechanisms underlying these phenomena are analyzed. Project supported by the National Natural Science Foundation of China (Grant Nos. 11365003 and 11165004).

  11. Abnormal fb Es enhancements in equatorial Es layers during magnetic storms of solar cycle 23

    NASA Astrophysics Data System (ADS)

    Resende, L. C. A.; Denardini, C. M.; Batista, I. S.

    2013-09-01

    We have analyzed the behavior of blanketing frequency of the Es layer (fb Es) occurring at an equatorial station covering the days before, during and subsequent to 24 intense and very intense magnetic storms (Dst≤-100 nT) that occurred during the solar cycle 23. The fb Es was measured by digital ionosonde over São Luís, Brazil (2.33° S, 44.2° W, dip: -4.5°). Our analysis shows that there are significant changes in the fb Es, mainly during the recovery phase of magnetic storms, characterized by occurrence of peaks that exceed the ambient background values. Also, these peaks are associated to other types of sporadic E layer than the Esq (a non-blanketing layer detected due the plasma irregularities in the equatorial electrojet), which in turn means competing mechanisms. The results are discussed in terms of the statistics of the abnormal enhancement taking into account the phase of the magnetic storm.

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

    NASA Astrophysics Data System (ADS)

    Feng, X.

    2015-12-01

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

  13. Review Article: Storm Britta in 2006: offshore damage and large waves in the North Sea

    NASA Astrophysics Data System (ADS)

    Kettle, A. J.

    2015-09-01

    The Britta storm of 31 October-1 November 2006 was a severe autumn storm that was particularly damaging for shipping and coastal flooding from storm surge effects along the southern North Sea. The main low pressure of the storm propagated from Scotland to southern Norway on 31 October, leading to a system of strong north winds that moved southward across North Sea over an 18 h period. A progression of ship and offshore platform difficulties were registered from the northern part of the North Sea from late on 31 October and culminated near the coasts of Germany and the Netherlands early on 1 November with a series of ship emergencies linked with large waves. In two separate incidents, unusually high waves broke the bridge windows of ships and necessitated emergency rescues, and a Dutch motor lifeboat experienced a triple capsize. In the southern North Sea, several gas production and research platforms experienced wave impact damage. The FINO1 offshore research platform, near the Dutch-German border, experienced some of the worst storm conditions with some structural damage. Its meteorological and oceanographic instrumentation give a unique profile of the severe met-ocean conditions during the storm. Two Waverider buoys at FINO1 and the nearby Dutch coastal site of Schiermonnikoog recorded groups of large waves at different times during the storm. These reports give insight into a little-reported rogue wave phenomenon that sometimes accompanies the "ground sea" conditions of the worst storms of the area.

  14. Extreme storm wave influence on sandy beach macrofauna with distinct human pressures.

    PubMed

    Machado, Phillipe M; Costa, Leonardo L; Suciu, Marjorie C; Tavares, Davi C; Zalmon, Ilana R

    2016-06-15

    We evaluated the influence of storm waves on the intertidal community structure of urbanized and non-urbanized areas of a sandy beach on the northern coast of Rio de Janeiro, Brazil. The macrofauna was sampled before (PREV) and after two storm wave events (POEV I; POEV II) in 2013 and 2014. Significant differences in community structure between PREV and POEV I in the urbanized sector demonstrate higher macrofauna vulnerability, and the community recovery within 41days on this scenario of less frequent events in 2013. On the other hand, significant differences in the macrofauna only in the urbanized sector between PREV and POEV II also highlight macrofauna vulnerability and community recovery failure within 42days on this scenario of more frequent storm in 2014. Urbanization and wave height were the variables that most influenced species, indicating that high storm wave events and increasing urbanization synergism are a threat to the macrofauna. PMID:27103425

  15. Extreme storm wave influence on sandy beach macrofauna with distinct human pressures.

    PubMed

    Machado, Phillipe M; Costa, Leonardo L; Suciu, Marjorie C; Tavares, Davi C; Zalmon, Ilana R

    2016-06-15

    We evaluated the influence of storm waves on the intertidal community structure of urbanized and non-urbanized areas of a sandy beach on the northern coast of Rio de Janeiro, Brazil. The macrofauna was sampled before (PREV) and after two storm wave events (POEV I; POEV II) in 2013 and 2014. Significant differences in community structure between PREV and POEV I in the urbanized sector demonstrate higher macrofauna vulnerability, and the community recovery within 41days on this scenario of less frequent events in 2013. On the other hand, significant differences in the macrofauna only in the urbanized sector between PREV and POEV II also highlight macrofauna vulnerability and community recovery failure within 42days on this scenario of more frequent storm in 2014. Urbanization and wave height were the variables that most influenced species, indicating that high storm wave events and increasing urbanization synergism are a threat to the macrofauna.

  16. Planetary wave vacillations and storms in the Southern Hemisphere

    NASA Astrophysics Data System (ADS)

    Baldi, M.; Dalu, G. A.

    2009-04-01

    The planetary flow in the Southern Hemisphere (SH) is more zonally symmetric than the corresponding flow in the Northern Hemisphere (NH). In the upper troposphere, the wind is largest in the subtropical jet at 30°S stretching across Australia, and in the mid-latitude jet across the South Atlantic and Indian Ocean at 50°S. The sub-tropical jet weakens in the mid-troposphere, and it is absent in the lower troposphere. In the lower troposphere the annual average westerly wind is confined in a relatively narrow latitudinal band around 50°S (Lorenz and Hartmann, 2001). The zonal symmetric mode (ZW0) dominates the seasonal variance. The mode zero is modulated by two standing modes ZW1 and ZW3, which are excited by the continental topographic features and by the heat diabatic fluxes related to the SST gradients and to seasonal sea-land thermal contrast. Even if these modes are relatively weak (van Loon and Jenne, 1972, Hobbs and Raphael, 2007), they are important, since they dominate the seasonal zonal asymmetry of the planetary flow (van Loon and Jenne, 1972), with significant links with El Niño/La Niña southern oscillation (Trenberth, 1980; Renwick and Revell, 1999; Raphael, 2003). Analysis study has shown that mode ZW1 and ZW3 can exhibit chaotic like behaviour (Kidson, 1988, 1999). Vacillations of these modes with a quasi-periodicity of the order of 40 days can occur in regions of strong zonal wind because of non-linear wave-wave interaction (De Gregorio and Dalu, 1984). The onset of these vacillations can be triggered by the arrival of a higher order travelling wave in a region of strong zonal wind. In addition, the presence of these higher order modes shortens the time scale of the vacillations of mode ZW1 and ZW3. Finally an attempt is made to relate these vacillations to the diversion of the Antarctic storms towards the ANZ region.

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  18. Statistics and analysis of storm waves in the Sea of Azov

    NASA Astrophysics Data System (ADS)

    Silvestrova, Ksenia; Arkhipkin, Victor; Surkova, Galina

    2013-04-01

    For the study of storm waves in the Sea of Azov spectral wave model of the third-generation SWAN (Simulating Waves Nearshore) was used. The inputs to the model were the bottom topography in grid (pitch axis x 0,02 ° and the axis y 0,01 °) and wind field of a new high-resolution(~ 0.3°) reanalysis NCEP CFSR from 1978 to 2010 with a time step of 1 hour. This model calculates significant wave height, swell height, direction of wave propagation, its length and the period, and the wave energy transport. The time interval output was 3 hours. Results of calculation of the last 2 days of the year are used as input for the next year. Supercomputers of Lomonosov Moscow State University were used for this research. The physical processes such as quadruplet interactions, whitecapping, triads, bottom friction, depth-induced breaking and diffraction are considered. The simulation results were used to calculate the number of storms, their duration, for the period of settlement, and for each month. Total number of storms with significant wave height greater than 2 m was 165. The highest values of calculated parameters are found in the central part of the sea: significant wave height is 3.5 m, a period of waves is 5 seconds, the length is 25 m. According to model simulation, the distribution of waves with 100 years return period were calculated. As a result, it was found that the heights of "100-year" waves in the Sea of Azov do not exceed 5 m. The study presents climatic variability of storms. Found that there was downward trend of storm activity in the Sea of Azov in the simulating period from 1978 to 2010. Synoptic situations that led to increase of storm waves were analyzed for extreme cases. The work is done in Natural Risk Assessment Laboratory under contract G.34.31.0007.

  19. Influence of Wave Energetics on Nearshore Storms and Adjacent Shoreline Morphology

    NASA Astrophysics Data System (ADS)

    Wadman, H. M.; McNinch, J. E.; Hanson, J.

    2008-12-01

    Large-scale climatic forcings (such as NAO and ENSO) are known to induce fluctuations in regional storm frequency and intensity. Morphology-based studies have traditionally focused on individual storms and their influence on the nearshore coastal wave regime and shoreline response. Few studies have attempted to link long-term observed changes in shoreline position, beach, and nearshore morphology with large-scale climatic forcings that influence regional storm patterns. In order to predict the response of coastlines to future sea level rise and climate change, we need to understand how changes in the frequency of storms affecting nearshore regions (nearshore storms) may influence trends in shoreline position and nearshore morphology. Nearly 30 years of wave data (deep and shallow) collected off of Duck, NC are examined for trends in storm frequency and/or intensity. Changes in shoreline position and shoreface elevation, as observed from monthly beach transects over the same period, are also investigated in light of the observed trends in hydrodynamic forcings. Our preliminary analysis was unable to identify any consistent linear trends (increases or decreases) in frequency or intensity over the ~30-year time period in either the offshore wave heights or the nearshore storm record. These data might suggest that previous observations of recent increases in storm intensity and frequency, speculated to be due to climate change, might be spatially limited. Future analyses will partition the contributions from individual wind sea and swell events in order to better identify long-term trends in wave energetics from the various wave generation regions in the Atlantic. At this location, offshore wave height and the nearshore storm record are dominated by seasonal fluctuations and a strong interdecadal- to decadal periodicity. Previous research in Duck, NC has suggested that changes in shoreline position and shoreface elevations are related both to seasonal trends as well as

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

    NASA Astrophysics Data System (ADS)

    Xie, Lian; Liu, Huiqing; Peng, Machuan

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

  1. Prediction of Significant Wave Heights in Extreme Storms Affecting Far North Alaska

    NASA Astrophysics Data System (ADS)

    Cassano, E. N.; Thornbrugh, C.; Lynch, A.

    2003-12-01

    Barrow, Alaska is located at the northernmost point of the United States on the shore of the Arctic Ocean. The area surrounding Barrow is low lying and is thus vulnerable to coastal flooding via waves and storm surges. Previous modeling of flooding resulting from a storm that affected Barrow and the rest of the North Slope coast region in October 1963 did not reproduce observed flooding, which was substantially greater than modeled. It is hypothesized that because this model only incorporated storm surge and not waves, the model was unable to simulate the total amount of flooding. The current study examines a recent storm that affected the North Slope of Alaska on July 28-30, 2003, and includes prediction of wave height using the SWAN (Simulating WAves Nearshore) model. In addition this study considers the formation and development, climatological context, and community responses for this storm. Results from the wave modeling portion of this study will be incorporated into a coastal flooding model in order to better simulate the coastal environment under extreme conditions in this area.

  2. Ionospsheric observation of enhanced convection-initiated gravity waves during tornadic storms

    NASA Technical Reports Server (NTRS)

    Hung, R. J.

    1981-01-01

    Atmospheric gravity waves associated with tornadoes, with locally severe storms occuring with tornadoes, and with hurricanes were studied through the coupling between the ionosphere and the troposphere. Reverse group ray tracing computations of gravity waves observed by an ionospheric Doppler sounder array were analyzed. The results of ray tracing computations and comparisons between the computed location of the wave sources and with conventional meteorological data indicate that the computed sources of the waves were near the touchdown of the tornadoes, near the eye of the hurricanes, and directly on the squall line of the severe thunderstorms. The signals excited occurred one hour in advance of the tornadoes and three hours in advance of the hurricanes. Satellite photographs show convective overshooting turrets occurring at the same locations and times the gravity waves were being excited. It is suggested that gravity wave observations, conventional meteorological data, and satellite photographs be combined to develop a remote sensing technique for detecting severe storms.

  3. Alfvén wave-driven ionospheric mass outflow and electron precipitation during storms

    NASA Astrophysics Data System (ADS)

    Hatch, S. M.; Chaston, C. C.; LaBelle, J.

    2016-08-01

    We explore the global Alfvénic response of the transition region between the topside ionosphere and magnetosphere to geomagnetic storms. From superposed epoch and storm phase-dependent analyses, it is found that subsequent to storm commencement the occurrence rate of Alfvénic field variations on electron inertial scales through this region increases by as much as a factor of 5 relative to prestorm levels. This increase is accompanied by order-of-magnitude enhancements in coincident energy deposition rates into the ionosphere and ion outflow rates into the magnetosphere, particularly near noon, premidnight, and on the dawn flank. During main phase on the dayside these waves shift to lower invariant latitudes (ILATs), expanding over a large range of ILATs and magnetic local times, where they are associated with significant enhancements in upward ion flux. Nightside storm-enhanced occurrence probability of Alfvén waves and upward ion flux is lower than on the dayside, but the average precipitating electron energy flux is larger. There is also a localized region of intense ion outflow premidnight at low latitudes during storm main phase. Wave occurrence rates subside to prestorm levels about 20 h after storm commencement.

  4. Multi-spacecraft observations of ULF waves during the Halloween storm

    NASA Astrophysics Data System (ADS)

    Daglis, I. A.; Balasis, G.; Zesta, E.; Papadimitriou, C.; Georgiou, M.; Horne, R. B.; Khotyaintsev, Y. V.; Mann, I. R.; Santolik, O.; Turner, D. L.

    2012-12-01

    The "Halloween" storm (on 29 - 31 October 2003) has attracted considerable interest as it offers a great opportunity of understanding the response of the magnetosphere-ionosphere system to strong and continuous solar wind driving through the analysis of combined ground and space data. In this paper, we first present the overall ULF wave activity throughout the three-day interval as observed by Cluster, Geotail, and CHAMP in the variations of the observed magnetic field. We also look at three specific intervals during different phases of the storm when at least two of the spacecraft are in good local time conjunction. We examine separately the Pc3 and Pc4-5 ULF wave activity and its concurrence in the different regions of the magnetosphere and down to the topside ionosphere. We find that the wave content in the magnetosphere is higher due to the storm. The wave power in the topside ionosphere, which is sensitive to ionospheric currents, is directly correlated with Dst. In the magnetosphere, on the other hand, Pc5 wave power exhibits a stronger correlation to Dst, while the Pc3 power exhibits more of an overall linear increase with time from storm onset. At the topside ionosphere the Pc3 wave power - Dst correlation is more prominent than it is in the magnetosphere. Geotail is in the upstream solar wind at the initial main phase of the storm and observes significantly enhanced ULF wave power with the approach of the CME and storm-time conditions. It appears that much of the wave power dynamics observed inside the magnetosphere and ionosphere may be directly driven by wave dynamics inside the solar wind. Local time conjunctions of any satellite combination demonstrate that the dynamic development of the wave power of either Pc3 or Pc4-5 waves is well correlated between the different regions of the magnetosphere and from the magnetosphere to the ionosphere. Correlations between spacecraft in different local time sectors are more generic in terms of the occurrence of

  5. Tidal and storm wave deposition in Lower Silurian shelf sequences, east Tennessee

    SciTech Connect

    Driese, S.G.; Fischer, M.W.; Easthouse, K.A.; Schoner, A.E.

    1986-05-01

    Lower Silurian sequences exposed across east Tennessee consist of an easterly quartzarenite (Clinch Sandstone) that grades westward into heterolithic sandstone, siltstone, and shale (Rockwood Formation). Farther west, the sequence intertongues with a cratonic carbonate-shale succession (Brassfield Formation). The Clinch Sandstone represents deposition in shoreface and inner shelf environments. Inferred depositional processes include (1) ebb-dominated tidal currents, (2) wave-induced currents (longshore and shore-oblique), and (3) wave-orbital currents. Strong tidal influence is indicated by abundant medium to large-scale, variably stacked sets of ebb-oriented (west-northwest) cross-strata. These strata exhibit tidal bundling, double clay drapes, reactivation/pause surfaces containing concentrations of shale intraclasts and/or biogenic structures, and shale intraclasts lining deep scours. The cross-strata were produced by migration of large-scale, low-amplitude bed forms (class II, III, and IV sand wave of Allen), and densely bioturbated sequences are interbedded with the cross-strata dominated by Skolithos-assemblage traces. The Rockwood Formation represents deposition in middle to outer shelf environments where storm-induced currents dominated. Possible depositional mechanisms include (1) storm-surge-ebb (relaxation) flows associated with coastal set-up conditions, which may have evolved into geostrophic flows; and (2) turbidity flows initiated by storm-induced liquefaction of shoreface sand. Features suggest deposition above fair-weather wave base (high-angle cross-strata), below fair-weather wave base but within storm wave base (hummocky cross-stratification, microhummocky cross-stratification and wave ripples), and below storm wave base (Bouma bce turbidites). Westerly sand transport was most prevalent, and bioturbation is extensive and dominated by Cruziana-assemblage traces.

  6. Effect of wave-enhanced bottom friction on storm-driven circulation in Massachusetts Bay

    USGS Publications Warehouse

    Signell, R.P.; List, J.H.

    1997-01-01

    Massachusetts Bay is a shallow (35 m average depth) semienclosed embayment, roughly 100 ?? 50 km, which opens into the Gulf of Maine at its eastern boundary. Surface waves associated with winter storm winds from the northeast cause large sediment resuspension events, and wave and circulation fields during these events have a quasi-steady response to the wind stress. Coupled wave, circulation, and boundary layer models indicate that wave-enhanced bottom friction has a significant damping effect on storm-driven circulation in Massachusetts Bay. The simulated response exhibits significant three-dimensional structure, but still can be fundamentally understood using idealized models. The depth-integrated momentum balance is dominated by along-bay stress, pressure gradient, and bottom stress. The effective bottom drag coefficient during typical storm conditions is increased by a factor of 2-5 when wave effects are included, but the mean bottom stress is relatively unaffected by wave effects due to a reduction in bottom currents by 30-50%. The vertical mixing is also relatively unaffected by the waves, and the result is that the increased drag causes a nearly depth-independent offset of the vertical current profiles. The alongshore transport in the bay is reduced 10-50%, depending on wind direction. ?? ASCE.

  7. Wave-current interaction in the bottom boundary layer during storm and non-storm conditions: observations and model predictions

    USGS Publications Warehouse

    Drake, D.E.; Cacchione, D.A.

    1992-01-01

    Bottom boundary layer measurements of current velocity profiles and bed response under combined wave and current conditions were obtained at a water depth of 145 m on the shelf off central California during December 1988. High quality logarithmic current profiles, excellent time-series bottom photographs, and a large variation in the relative strengths of the wave-induced oscillatory currents and the quasi-steady low frequency currents provided a dataset that is ideal for examining the effects of wave-current interaction near a rough boundary. During one period of 3 days that included a brief storm event, the wave-induced bottom currents (Ub 1 10) ranged from 2.3 to 22 cm s-1 and the steady currents (Ur) ranged from 1.8 to 28.1 cm s-1 at 0.18 m above the bottom; the ratio Ub U18 varied from below 0.2 to more than 7. Velocity profiles were highly logarithmic (R2 > 0.95) 60% of the time and 27 profiles collected at 2-h intervals had R2 {slanted equal to or greater-than} 0.994 which allowed reliable estimates of the current shear velocity (U*c) and roughness length (zoc). Mean U*c values had magnitudes of 0.3-2.4 cm s-1 and zoc, which ranged from 0.04 to 3.5 cm, was strongly correlated to the Ub U18 ratio. Drag coefficients (CD = ??c/??U1002) ranged from about 2.5 ?? 10-3-12 ?? 10-3 in direct response to the wave-current variation; the use of a constant CD of 3 ?? 10-3 for steady flow over a rough bed would have underpredicted the shear stress by up to four times during the storm event. The large zoc and U*c values cannot be explained by changes in the carefully-observed, small (<1 cm) physical bed roughness elements that covered the mud-rich study site. A side-scan sonar site survey also eliminated the possibility of flow disturbance by larger upstream topography. The observations clearly demonstrate the importance of wave-current interaction near a rough boundary. Comparison of the observations with results of the combined flow models of Grant and Madsen and Glenn

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

    NASA Astrophysics Data System (ADS)

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

    2016-08-01

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

  9. Northeast storms ranked by wind stress and wave-generated bottom stress observed in Massachusetts Bay, 1990-2006

    USGS Publications Warehouse

    Butman, B.; Sherwood, C.R.; Dalyander, P.S.

    2008-01-01

    Along the coast of the northeastern United States, strong winds blowing from the northeast are often associated with storms called northeasters, coastal storms that strongly influence weather. In addition to effects caused by wind stress, the sea floor is affected by bottom stress associated with these storms. Bottom stress caused by orbital velocities associated with surface waves integrated over the duration of a storm is a metric of storm strength at the sea floor. Near-bottom wave-orbital velocities calculated by using measurements of significant wave height and dominant wave period and the parametric spectral method described in Wiberg and Sherwood [Wiberg, P.L., Sherwood, C.R. Calculating wave-generated bottom orbital velocities from surface wave parameters. Computers in Geosciences, in press] compared well with observations in Massachusetts Bay. Integrated bottom-wave stress (called IWAVES), calculated at 30 m water depth, and a companion storm-strength metric, integrated surface wind stress at 10 m (called IWINDS), are used to provide an overview of the strength, frequency, and timing of large storms in Massachusetts Bay over a 17-year period from January 1990 through December 2006. These new metrics reflect both storm duration and intensity. Northeast storms were the major cause of large waves in Massachusetts Bay because of the long fetch to the east: of the strongest 10% of storms (n=38) ranked by IWAVES, 22 had vector-averaged wind stress from the northeast quadrant. The Blizzard of December 1992, the Perfect Storm of October 1991, and a December 2003 storm were the strongest three storms ranked by IWAVES and IWINDS, and all were northeasters. IWAVES integrated over the winter season (defined as October-May) ranged by about a factor of 11; the winters with the highest integrated IWAVES were 1992-1993 and 2004-2005 and the winter with the lowest integrated IWAVES was 2001-2002. May 2005 was the only month in the 17-year record that two of the nine

  10. Wave-driven sediment mobilization on a storm-controlled continental shelf (Northwest Iberia)

    USGS Publications Warehouse

    Oberle, Ferdinand; Storlazzi, Curt D.; Hanebuth, Till

    2014-01-01

    Seafloor sediment mobilization on the inner Northwest Iberian continental shelf is caused largely by ocean surface waves. The temporal and spatial variability in the wave height, wave period, and wave direction has a profound effect on local sediment mobilization, leading to distinct sediment mobilization scenarios. Six grain-size specific sediment mobilization scenarios, representing seasonal average and storm conditions, were simulated with a physics-based numerical model. Model inputs included meteorological and oceanographic data in conjunction with seafloor grain-size and the shelf bathymetric data. The results show distinct seasonal variations, most importantly in wave height, leading to sediment mobilization, specifically on the inner shelf shallower than 30 m water depth where up to 49% of the shelf area is mobilized. Medium to severe storm events are modeled to mobilize up to 89% of the shelf area above 150 m water depth. The frequency of each of these seasonal and storm-related sediment mobilization scenarios is addressed using a decade of meteorological and oceanographic data. The temporal and spatial patterns of the modeled sediment mobilization scenarios are discussed in the context of existing geological and environmental processes and conditions to assist scientific, industrial and environmental efforts that are directly affected by sediment mobilization. Examples, where sediment mobilization plays a vital role, include seafloor nutrient advection, recurrent arrival of oil from oil-spill-laden seafloor sediment, and bottom trawling impacts.

  11. Wave-driven sediment mobilization on a storm-controlled continental shelf (Northwest Iberia)

    NASA Astrophysics Data System (ADS)

    Oberle, Ferdinand K. J.; Storlazzi, Curt D.; Hanebuth, Till J. J.

    2014-11-01

    Seafloor sediment mobilization on the inner Northwest Iberian continental shelf is caused largely by ocean surface waves. The temporal and spatial variability in the wave height, wave period, and wave direction has a profound effect on local sediment mobilization, leading to distinct sediment mobilization scenarios. Six grain-size specific sediment mobilization scenarios, representing seasonal average and storm conditions, were simulated with a physics-based numerical model. Model inputs included meteorological and oceanographic data in conjunction with seafloor grain-size and the shelf bathymetric data. The results show distinct seasonal variations, most importantly in wave height, leading to sediment mobilization, specifically on the inner shelf shallower than 30 m water depth where up to 49% of the shelf area is mobilized. Medium to severe storm events are modeled to mobilize up to 89% of the shelf area above 150 m water depth. The frequency of each of these seasonal and storm-related sediment mobilization scenarios is addressed using a decade of meteorological and oceanographic data. The temporal and spatial patterns of the modeled sediment mobilization scenarios are discussed in the context of existing geological and environmental processes and conditions to assist scientific, industrial and environmental efforts that are directly affected by sediment mobilization. Examples, where sediment mobilization plays a vital role, include seafloor nutrient advection, recurrent arrival of oil from oil-spill-laden seafloor sediment, and bottom trawling impacts.

  12. Storm Time EMIC Waves and Their Relationship to Plasmaspheric Density, Plasma Plumes and Radiation Belt Particle Loss

    NASA Astrophysics Data System (ADS)

    Halford, A. J.; Fraser, B. J.; Morley, S.; Koller, J.; Friedel, R. H.

    2011-12-01

    Electromagnetic ion cyclotron (EMIC) waves have been observed to have a higher occurrence rate during geomagnetic storms than during quiet magnetospheric conditions and are thought to contribute to the loss processes of the ring current and radiation belts. In particular, CRRES EMIC wave activity shows a maximum occurrence rate during the storm main phase, when the storm time ring current particle injection is most likely to over lap with the plasmasphere and plasmaspheric plumes. In this study we will report on the relationship between the plasmasphere, plasmaspheric plumes and the occurrence of EMIC waves seen during the storm main and recovery phases. We will also look at the pitch angle diffusion coefficients found for EMIC waves occurring during the main and recovery phases of a geomagnetic storm. The EMIC wave dataset used in this study comes from the CRRES mission that includes over 900 EMIC wave events and over 100 geomagnetic storms over 1990-1991. By comparing the like phases between storms we are able to improve our understanding of the magnetospheric and plasma conditions that are observed in association with EMIC waves, and how these relate to loss processes in the radiation belts.

  13. Particles, waves and storms in geospace: Recent advances and persistent gaps in our comprehension

    NASA Astrophysics Data System (ADS)

    Daglis, Ioannis A.

    2016-07-01

    The terrestrial magnetosphere features plasma populations with a wide dynamic range of energies, spanning more than 8 orders of magnitude -- from ≃V in the plasmasphere to tens of MeV in the outer Van Allen belt and hundreds of MeV in the inner Van Allen belt. A wealth of in-situ measurements of particles and waves, and ground-based measurements of waves, has shaped a comprehensive understanding of the interactions of the various plasma populations with electromagnetic waves during geospace magnetic storms and magnetospheric substorms. We shall discuss recent advances and persistent gaps in our comprehension of inner magnetosphere dynamics.

  14. Myocardial ischemic hyperacute T-wave oversensing leading to a defibrillator shock storm

    PubMed Central

    Khalid, Nauman; Kluger, Jeffrey

    2015-01-01

    Appropriate sensing is essential for the normal functioning of an implantable cardioverter defibrillator (ICD). T-wave oversensing is a potential clinical problem in ICD patients that may result in inappropriate shocks. Oversensing may have various underlying causes and can be treated with noninvasive or invasive means. We present the case of a 45-year-old man presenting with shock storm as a result of T-wave oversensing. Workup revealed a hemodynamically significant stenosis of the left anterior descending artery treated with percutaneous coronary intervention and drug-eluting stent placement. This resulted in the resolution of T-wave missensing and restoration of normal ICD functioning. PMID:25829654

  15. Prey localization by surface wave ray-tracing: fish track bugs like oceanographers track storms.

    PubMed

    Käse, R H; Bleckmann, H

    1987-03-15

    Surface-feeding fish accurately determine direction and distance to the center of a concentric wave stimulus, even if only a single, short lasting wave train is presented. It has been suggested that one cue used by these fish to localize the wave center is the distance dependent frequency modulation of the initial part of a wave stimulus. Here we show how the distance information contained in the fractional frequency change of a capillary wave group can be decoded. We suggest that wave source localization in surface-feeding fish in part is based on a principal similar to that used by oceanographers to track storms by the frequency change of forerunners of swell.

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

    NASA Astrophysics Data System (ADS)

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

    2012-07-01

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

  17. Gravity shear waves atop the cirrus layer of intense convective storms

    NASA Technical Reports Server (NTRS)

    Stobie, J. G.

    1975-01-01

    Recent visual satellite photographs of certain intense convective storms have revealed concentric wave patterns. A model for the generation and growth of these waves is proposed. The proposed initial generating mechanism is similar to the effect noticed when a pebble is dropped into a calm pond. The penetration of the tropopause by overshooting convection is analogous to the pebble's penetration of the water's surface. The model for wave growth involves instability due to the wind shear resulting from the cirrus outflow. This model is based on an equation for the waves' phase speed which is similar to the Helmholtz equation. It, however, does not assume an incompressible atmosphere, but rather assumes density is a logarithmic function of height. Finally, the model is evaluated on the two mid-latitude and three tropical cases. The data indicate that shearing instability may be a significant factor in the appearance of these waves.

  18. EMIC waves observed by the low-altitude satellite DEMETER during the November 2004 magnetic storm

    NASA Astrophysics Data System (ADS)

    Píša, D.; Parrot, M.; Santolík, O.; Menietti, J. D.

    2015-07-01

    This paper presents an analysis of ULF (0-20 Hz) waves observed by the low-altitude satellite Detection of Electro-Magnetic Emissions Transmitted from Earthquake Regions (DEMETER) during the magnetic storm of November 2004. Since these ULF waves are measured by both electric and magnetic antennas, they may be identified as electromagnetic ion cyclotron (EMIC) waves. While EMIC waves have been previously observed in the low-altitude ionosphere, this is the first time that they are observed for such extensive time periods and at such high frequencies. A common feature of these emissions is that their observation region in the low-altitude ionosphere extends continuously from the high-latitude southern trough in one side up to the high-latitude northern trough. The analysis of wave propagation points to the possible source region placed in the inner magnetosphere (L ˜ 2-3). Observed wave frequencies indicate that waves must be generated much farther from the Earth compared to the satellite orbit. Exceptionally high frequencies of about 10 Hz can be explained by the source region placed in the deep inner magnetosphere at L ˜ 2.5. We hypothesize that these waves are generated below the local helium gyrofrequency and propagate over a large range of wave normal angles to reach low altitudes at L ˜ 1.11. In order to investigate this scenario, a future study based on ray tracing simulations will be necessary.

  19. Observation of acoustic-gravity waves in the upper atmosphere during severe storm activity

    NASA Technical Reports Server (NTRS)

    Hung, R. J.

    1975-01-01

    A nine-element continuum wave spectrum, high-frequency, Doppler sounder array has been used to detect upper atmospheric wave-like disturbances during periods with severe weather activity, particularly severe thunderstorms and tornadoes. Five events of severe weather activity, including extreme tornado outbreak of April 3, 1974, were chosen for the present study. The analysis of Doppler records shows that both infrasonic waves and gravity waves were excited when severe storms appeared in the north Alabama area. Primarily, in the case of tornado activity, S-shaped Doppler fluctuations or Doppler fold-backs are observed, while quasi-sinusoidal fluctuations are more common in the case of thunderstorm activity. A criterion for the production of Doppler fold-backs is derived and compared with possible tornado conditions.

  20. GCM response of northern winter stationary waves and storm tracks to increasing amounts of carbon dioxide

    SciTech Connect

    Stephenson, D.B.; Held, I.M. )

    1993-10-01

    The response of the Geophysical Fluid Dynamics Laboratory (GFDL) coupled ocean-atmosphere R15, 9-level GCM to gradually increasing CO[sub 2] amounts is analyzed with emphasis on the changes in the stationary waves and storm tracks in the Northern Hemisphere wintertime troposphere. A large part of the change is described by an equivalent-barotropic stationary wave with a high over eastern Canada and a low over southern Alaska. Consistent with this, the Atlantic jet weakens near the North American coast. Perpetual winter runs of an R15, nine-level atmospheric GCM with sea surface temperature, sea ice thickness, and soil moisture values prescribed from the coupled GCM results are able to reproduce the coupled model's response qualitatively. Consistent with the weakened baroclinicity associated with the stationary wave change, the Atlantic storm track weakens with increasing CO[sub 2] concentrations while the Pacific storm track does not change in strength substantially. An R15, nine-level atmospheric model linearized about the zonal time-mean state is used to analyze the contributions to the stationary wave response. With mountains, diabatic heating, and transient forcings the linear model gives a stationary wave change in qualitative agreement with the change seen in the coupled and perpetual models. Transients and diabatic heating appear to be the major forcing terms, while changes in zonal-mean basic state and topographic forcing play only a small role. A substantial part of the diabatic response is due to changes in tropical latent heating. 25 refs., 36 figs.

  1. Invasive grasses, climate change, and exposure to storm-wave overtopping in coastal dune ecosystems.

    PubMed

    Seabloom, Eric W; Ruggiero, Peter; Hacker, Sally D; Mull, Jeremy; Zarnetske, Phoebe

    2013-03-01

    The world's coastal habitats are critical to human well-being, but are also highly sensitive to human habitat alterations and climate change. In particular, global climate is increasing sea levels and potentially altering storm intensities, which may result in increased risk of flooding in coastal areas. In the Pacific Northwest (USA), coastal dunes that protect the coast from flooding are largely the product of a grass introduced from Europe over a century ago (Ammophila arenaria). An introduced congener (A. breviligulata) is displacing A. arenaria and reducing dune height. Here we quantify the relative exposure to storm-wave induced dune overtopping posed by the A. breviligulata invasion in the face of projected multi-decadal changes in sea level and storm intensity. In our models, altered storm intensity was the largest driver of overtopping extent, however the invasion by A. breviligulata tripled the number of areas vulnerable to overtopping and posed a fourfold larger exposure than sea-level rise over multi-decadal time scales. Our work demonstrates the importance of a transdisciplinary approach that draws on insights from ecology, geomorphology, and civil engineering to assess the vulnerability of ecosystem services in light of global change. PMID:23504839

  2. Invasive grasses, climate change, and exposure to storm-wave overtopping in coastal dune ecosystems.

    PubMed

    Seabloom, Eric W; Ruggiero, Peter; Hacker, Sally D; Mull, Jeremy; Zarnetske, Phoebe

    2013-03-01

    The world's coastal habitats are critical to human well-being, but are also highly sensitive to human habitat alterations and climate change. In particular, global climate is increasing sea levels and potentially altering storm intensities, which may result in increased risk of flooding in coastal areas. In the Pacific Northwest (USA), coastal dunes that protect the coast from flooding are largely the product of a grass introduced from Europe over a century ago (Ammophila arenaria). An introduced congener (A. breviligulata) is displacing A. arenaria and reducing dune height. Here we quantify the relative exposure to storm-wave induced dune overtopping posed by the A. breviligulata invasion in the face of projected multi-decadal changes in sea level and storm intensity. In our models, altered storm intensity was the largest driver of overtopping extent, however the invasion by A. breviligulata tripled the number of areas vulnerable to overtopping and posed a fourfold larger exposure than sea-level rise over multi-decadal time scales. Our work demonstrates the importance of a transdisciplinary approach that draws on insights from ecology, geomorphology, and civil engineering to assess the vulnerability of ecosystem services in light of global change.

  3. Characteristics of storms driving wave-induced seafloor mobility on the U.S. East Coast continental shelf

    USGS Publications Warehouse

    Dalyander, P. Soupy; Butman, Bradford

    2015-01-01

    This study investigates the relationship between spatial and temporal patterns of wave-driven sediment mobility events on the U.S. East Coast continental shelf and the characteristics of the storms responsible for them. Mobility events, defined as seafloor wave stress exceedance of the critical stress of 0.35 mm diameter sand (0.2160 Pa) for 12 or more hours, were identified from surface wave observations at National Data Buoy Center buoys in the Middle Atlantic Bight (MAB) and South Atlantic Bight (SAB) over the period of 1997-2007. In water depths ranging from 36-48 m, there were 4-9 mobility events/year of 1-2 days duration. Integrated wave stress during events (IWAVES) was used as a combined metric of wave-driven mobility intensity and duration. In the MAB, over 67% of IWAVES was caused by extratropical storms, while in the SAB, greater than 66% of IWAVES was caused by tropical storms. On average, mobility events were caused by waves generated by storms located 800+ km away. Far-field hurricanes generated swell 2-4 days before the waves caused mobility on the shelf. Throughout most of the SAB, mobility events were driven by storms to the south, east, and west. In the MAB and near Cape Hatteras, winds from more northerly storms and low-pressure extratropical systems in the mid-western U.S. also drove mobility events. Waves generated by storms off the SAB generated mobility events along the entire U.S. East Coast shelf north to Cape Cod, while Cape Hatteras shielded the SAB area from swell originating to the north offshore of the MAB.

  4. A Proton-Cyclotron Wave Storm Generated by Unstable Proton Distribution Functions in the Solar Wind

    NASA Technical Reports Server (NTRS)

    Wicks, R. T.; Alexander, R. L.; Stevens, M.; Wilson, L. B., III; Moya, P. S.; Vinas, A.; Jian, L. K.; Roberts, D. A.; O’Modhrain, S.; Gilbert, J. A.; Zurbuchen, T. H.

    2016-01-01

    We use audification of 0.092 seconds cadence magnetometer data from the Wind spacecraft to identify waves with amplitudes greater than 0.1 nanoteslas near the ion gyrofrequency (approximately 0.1 hertz) with duration longer than 1 hour during 2008. We present one of the most common types of event for a case study and find it to be a proton-cyclotron wave storm, coinciding with highly radial magnetic field and a suprathermal proton beam close in density to the core distribution itself. Using linear Vlasov analysis, we conclude that the long-duration, large-amplitude waves are generated by the instability of the proton distribution function. The origin of the beam is unknown, but the radial field period is found in the trailing edge of a fast solar wind stream and resembles other events thought to be caused by magnetic field footpoint motion or interchange reconnection between coronal holes and closed field lines in the corona.

  5. A multivariate extreme wave and storm surge climate emulator based on weather patterns

    NASA Astrophysics Data System (ADS)

    Rueda, A.; Camus, P.; Tomás, A.; Vitousek, S.; Méndez, F. J.

    2016-08-01

    Coastal floods often coincide with large waves, storm surge and tides. Thus, joint probability methods are needed to properly characterize extreme sea levels. This work introduces a statistical downscaling framework for multivariate extremes that relates the non-stationary behavior of coastal flooding events to the occurrence probability of daily weather patterns. The proposed method is based on recently-developed weather-type methods to predict extreme events (e.g., significant wave height, mean wave period, surge level) from large-scale sea-level pressure fields. For each weather type, variables of interest are modeled using Generalized Extreme Value (GEV) distributions and a Gaussian copula for modelling the interdependence between variables. The statistical dependence between consecutive days is addressed by defining a climate-based extremal index for each weather type. This work allows attribution of extreme events to specific weather conditions, enhancing the knowledge of climate-driven coastal flooding.

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

  7. Stochastic analysis and modeling of abnormally large waves

    NASA Astrophysics Data System (ADS)

    Kuznetsov, Konstantin; Shamin, Roman; Yudin, Aleksandr

    2016-04-01

    In this work stochastics of amplitude characteristics of waves during the freak waves formation was estimated. Also amplitude characteristics of freak wave was modeling with the help of the developed Markov model on the basis of in-situ and numerical experiments. Simulation using the Markov model showed a great similarity of results of in-situ wave measurements[1], results of directly calculating the Euler equations[2] and stochastic modeling data. This work is supported by grant of Russian Foundation for Basic Research (RFBR) n°16-35-00526. 1. K. I. Kuznetsov, A. A. Kurkin, E. N. Pelinovsky and P. D. Kovalev Features of Wind Waves at the Southeastern Coast of Sakhalin according to Bottom Pressure Measurements //Izvestiya, Atmospheric and Oceanic Physics, 2014, Vol. 50, No. 2, pp. 213-220. DOI: 10.1134/S0001433814020066. 2. R.V. Shamin, V.E. Zakharov, A.I. Dyachenko. How probability for freak wave formation can be found // THE EUROPEAN PHYSICAL JOURNAL - SPECIAL TOPICS Volume 185, Number 1, 113-124, DOI: 10.1140/epjst/e2010-01242-y 3.E. N. Pelinovsky, K. I. Kuznetsov, J. Touboul, A. A. Kurkin Bottom pressure caused by passage of a solitary wave within the strongly nonlinear Green-Naghdi model //Doklady Physics, April 2015, Volume 60, Issue 4, pp 171-174. DOI: 10.1134/S1028335815040035

  8. Characterizing the Long-Period ULF Wave Response to Magnetic Storms

    NASA Astrophysics Data System (ADS)

    Engebretson, M. J.; Simms, L. E.; Posch, J. L.; Hughes, W. J.

    2002-05-01

    This study presents an analysis of amplitude and bandwidth of long-period ULF wave power observed at several networks of ground magnetometer stations in the western hemisphere, at latitudes from the subauroral zone to the polar caps, during the magnetic storm intervals of September and October 1999, April and October 2000, and March-April 2001 identified by the GEM research community. The magnetometer stations in this study include the polar cap / cusp latitude arrays of MACCS and the U.S. Automated Geophysical Observatories (AGOs), and the auroral / subauroral latitude arrays of CANOPUS and the British Antarctic Survey (BAS) AGOs. Comparison of the long-period pulsations (in the Pc5 frequency range) observed on the ground to the solar wind velocity and solar wind pressure confirms previous results that high solar wind velocity correlates well with increased Pc5-band power. Each storm exhibited narrow-band Pc5 wave activity during the recovery phase, but only in the dawn-noon sector at each site. During the main phase, and at all other local times during the recovery phase, wave activity was broadband.

  9. Self-Consistent Model of Magnetospheric Ring Current and Electromagnetic Ion Cyclotron Waves: The 2-7 May 1998 Storm

    NASA Technical Reports Server (NTRS)

    Khazanov, G. V.; Gamayunov, K. V.; Jordanova, V. K.

    2003-01-01

    A complete description of a self-consistent model of magnetospheric ring current interacting with electromagnetic ion cyclotron waves is presented. The model is based on the system of two kinetic equations; one equation describes the ring current ion dynamics, and another equation describes the wave evolution. The effects on ring current ions interacting with electromagnetic ion cyclotron waves and back on waves are considered self-consistently by solving both equations on a global magnetospheric scale under nonsteady state conditions. The developed model is employed to simulate the entire 2-7 May 1998 storm period. First, the trapped number fluxes of the ring current protons are calculated and presented along with comparison with the data measured by the three- dimensional hot plasma instrument Polar/HYDRA. Incorporating in the model the wave-particle interaction leads to much better agreement between the experimental data and the model results. Second, examining of the wave (MLT, L shell) distributions produced by the model during the storm progress reveals an essential intensification of the wave emission about 2 days after the main phase of the storm. This result is well consistent with the earlier ground-based observations. Finally, the theoretical shapes and the occurrence rates of the wave power spectral densities are studied. It is found that about 2 days after the storm s main phase on 4 May, mainly non-Gaussian shapes of power spectral densities are produced.

  10. A linear relationship between wave power and erosion determines salt-marsh resilience to violent storms and hurricanes.

    PubMed

    Leonardi, Nicoletta; Ganju, Neil K; Fagherazzi, Sergio

    2016-01-01

    Salt marsh losses have been documented worldwide because of land use change, wave erosion, and sea-level rise. It is still unclear how resistant salt marshes are to extreme storms and whether they can survive multiple events without collapsing. Based on a large dataset of salt marsh lateral erosion rates collected around the world, here, we determine the general response of salt marsh boundaries to wave action under normal and extreme weather conditions. As wave energy increases, salt marsh response to wind waves remains linear, and there is not a critical threshold in wave energy above which salt marsh erosion drastically accelerates. We apply our general formulation for salt marsh erosion to historical wave climates at eight salt marsh locations affected by hurricanes in the United States. Based on the analysis of two decades of data, we find that violent storms and hurricanes contribute less than 1% to long-term salt marsh erosion rates. In contrast, moderate storms with a return period of 2.5 mo are those causing the most salt marsh deterioration. Therefore, salt marshes seem more susceptible to variations in mean wave energy rather than changes in the extremes. The intrinsic resistance of salt marshes to violent storms and their predictable erosion rates during moderate events should be taken into account by coastal managers in restoration projects and risk management plans. PMID:26699461

  11. A linear relationship between wave power and erosion determines salt-marsh resilience to violent storms and hurricanes

    PubMed Central

    Leonardi, Nicoletta; Ganju, Neil K.; Fagherazzi, Sergio

    2016-01-01

    Salt marsh losses have been documented worldwide because of land use change, wave erosion, and sea-level rise. It is still unclear how resistant salt marshes are to extreme storms and whether they can survive multiple events without collapsing. Based on a large dataset of salt marsh lateral erosion rates collected around the world, here, we determine the general response of salt marsh boundaries to wave action under normal and extreme weather conditions. As wave energy increases, salt marsh response to wind waves remains linear, and there is not a critical threshold in wave energy above which salt marsh erosion drastically accelerates. We apply our general formulation for salt marsh erosion to historical wave climates at eight salt marsh locations affected by hurricanes in the United States. Based on the analysis of two decades of data, we find that violent storms and hurricanes contribute less than 1% to long-term salt marsh erosion rates. In contrast, moderate storms with a return period of 2.5 mo are those causing the most salt marsh deterioration. Therefore, salt marshes seem more susceptible to variations in mean wave energy rather than changes in the extremes. The intrinsic resistance of salt marshes to violent storms and their predictable erosion rates during moderate events should be taken into account by coastal managers in restoration projects and risk management plans. PMID:26699461

  12. A linear relationship between wave power and erosion determines salt-marsh resilience to violent storms and hurricanes.

    PubMed

    Leonardi, Nicoletta; Ganju, Neil K; Fagherazzi, Sergio

    2016-01-01

    Salt marsh losses have been documented worldwide because of land use change, wave erosion, and sea-level rise. It is still unclear how resistant salt marshes are to extreme storms and whether they can survive multiple events without collapsing. Based on a large dataset of salt marsh lateral erosion rates collected around the world, here, we determine the general response of salt marsh boundaries to wave action under normal and extreme weather conditions. As wave energy increases, salt marsh response to wind waves remains linear, and there is not a critical threshold in wave energy above which salt marsh erosion drastically accelerates. We apply our general formulation for salt marsh erosion to historical wave climates at eight salt marsh locations affected by hurricanes in the United States. Based on the analysis of two decades of data, we find that violent storms and hurricanes contribute less than 1% to long-term salt marsh erosion rates. In contrast, moderate storms with a return period of 2.5 mo are those causing the most salt marsh deterioration. Therefore, salt marshes seem more susceptible to variations in mean wave energy rather than changes in the extremes. The intrinsic resistance of salt marshes to violent storms and their predictable erosion rates during moderate events should be taken into account by coastal managers in restoration projects and risk management plans.

  13. A linear relationship between wave power and erosion determines salt-marsh resilience to violent storms and hurricanes

    USGS Publications Warehouse

    Leonardi, Nicoletta; Ganju, Neil K.; Fagherazzi, Sergio

    2016-01-01

    Salt marsh losses have been documented worldwide because of land use change, wave erosion, and sea-level rise. It is still unclear how resistant salt marshes are to extreme storms and whether they can survive multiple events without collapsing. Based on a large dataset of salt marsh lateral erosion rates collected around the world, here, we determine the general response of salt marsh boundaries to wave action under normal and extreme weather conditions. As wave energy increases, salt marsh response to wind waves remains linear, and there is not a critical threshold in wave energy above which salt marsh erosion drastically accelerates. We apply our general formulation for salt marsh erosion to historical wave climates at eight salt marsh locations affected by hurricanes in the United States. Based on the analysis of two decades of data, we find that violent storms and hurricanes contribute less than 1% to long-term salt marsh erosion rates. In contrast, moderate storms with a return period of 2.5 mo are those causing the most salt marsh deterioration. Therefore, salt marshes seem more susceptible to variations in mean wave energy rather than changes in the extremes. The intrinsic resistance of salt marshes to violent storms and their predictable erosion rates during moderate events should be taken into account by coastal managers in restoration projects and risk management plans.

  14. Past, present and future of wave climate, storms and morphological impacts on sandy coasts: Spain and Wales coasts examples.

    NASA Astrophysics Data System (ADS)

    Rangel-Buitrago, N. G.; Anfuso, G.; Phillips, M.; Thomas, T.

    2014-12-01

    Coastal response to climate events is very important for both socio-economic and environmental reasons. In order to carry out a correct coastal management program, it is important to provide realistic analysis of the natural variability and trend associated with climatic events (i.e. hurricanes, storms). In a scenario of rising sea level and increasing wave heights, the coastline will suffer huge impacts in terms of erosion and flooding especially with respect to low-lying regions that may partly or entirely disappear. This work deals with the analysis of a 22 year long wave buoy dataset recorded at Cadiz (SW Spain) and Tenby (S Wales, UK) with the objective of find the existing relationships between wave climate and coastal response. The analysis consisted in the characterization of winter wave climate, extreme waves and storms characteristics and distribution and their relationships with regional cycles (Teleconnection Patterns) such as the North Atlantic Oscillation (NAO) Index, the East Atlantic (EA) pattern and the Arctic Oscillation (AO), among others. Wave climate showed clear cyclic variations in average monthly significant wave height (Hs). Winter waves rapidly increased in height, reaching peak values (Hs = 1.2 m, Cadiz, Hs = 2.1 m, Tenby) between December and January. Energy patterns calculated using the equation of wave energy flux, showed average values of 37 kW/m and 155 kW/m respectively, during winter. In the same way, storm characterization in each study area was carried out using the Storm Power Index (Dolan and Davis, 1992) and five classes were obtained, from class I (weak) to V (extreme). Storm occurrence probability was 95% for class I (i.e. almost one event per year) to 5 % for class V. The return period for class V was 25 years and ranged from 5 to 8 years for classes III and IV storms, e.g. significant and severe events. Classes I and II showed a period of recurrence ranging from 1 to 3 years. For both areas high energy wave values were

  15. Modeling fresh water lens damage and recovery on atolls after storm-wave washover.

    PubMed

    Chui, Ting Fong May; Terry, James P

    2012-01-01

    The principal natural source of fresh water on scattered coral atolls throughout the tropical Pacific Ocean is thin unconfined groundwater lenses within islet substrates. Although there are many threats to the viability of atoll fresh water lenses, salinization caused by large storm waves washing over individual atoll islets is poorly understood. In this study, a mathematical modeling approach is used to examine the immediate responses, longer-term behavior, and subsequent (partial) recovery of a Pacific atoll fresh water lens after saline damage caused by cyclone-generated wave washover under different scenarios. Important findings include: (1) the saline plume formed by a washover event mostly migrates downward first through the top coral sand and gravel substrate, but then exits the aquifer to the ocean laterally through the more permeable basement limestone; (2) a lower water table position before the washover event, rather than a longer duration of storm washover, causes more severe damage to the fresh water lens; (3) relatively fresher water can possibly be found as a preserved horizon in the deeper part of an aquifer after disturbance, especially if the fresh water lens extends into the limestone under normal conditions; (4) post-cyclone accumulation of sea water in the central depression (swamp) of an atoll islet prolongs the later stage of fresh water lens recovery. PMID:21883195

  16. Modeling fresh water lens damage and recovery on atolls after storm-wave washover.

    PubMed

    Chui, Ting Fong May; Terry, James P

    2012-01-01

    The principal natural source of fresh water on scattered coral atolls throughout the tropical Pacific Ocean is thin unconfined groundwater lenses within islet substrates. Although there are many threats to the viability of atoll fresh water lenses, salinization caused by large storm waves washing over individual atoll islets is poorly understood. In this study, a mathematical modeling approach is used to examine the immediate responses, longer-term behavior, and subsequent (partial) recovery of a Pacific atoll fresh water lens after saline damage caused by cyclone-generated wave washover under different scenarios. Important findings include: (1) the saline plume formed by a washover event mostly migrates downward first through the top coral sand and gravel substrate, but then exits the aquifer to the ocean laterally through the more permeable basement limestone; (2) a lower water table position before the washover event, rather than a longer duration of storm washover, causes more severe damage to the fresh water lens; (3) relatively fresher water can possibly be found as a preserved horizon in the deeper part of an aquifer after disturbance, especially if the fresh water lens extends into the limestone under normal conditions; (4) post-cyclone accumulation of sea water in the central depression (swamp) of an atoll islet prolongs the later stage of fresh water lens recovery.

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

    NASA Astrophysics Data System (ADS)

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

    2013-09-01

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

  18. An European historical reconstruction of sea surface dynamics (waves and storm surge) for coastal impact studies

    NASA Astrophysics Data System (ADS)

    Menendez, Melisa; Perez, Jorge; Cid, Alba; Castanedo, Sonia; Losada, Inigo; Medina, Raul; Mendez, Fernando

    2015-04-01

    Despite their outstanding relevance in coastal processes, a study of the sea surface dynamics due to atmospheric wind and pressure variations are rather limited in comparison with the mean sea level rise. Data of waves and surges along the European region are scarce and in-homogeneous, not only in terms of spatial coverage but also in terms of temporal coverage. This study presents two databases focused on a historical reconstruction of: (i) the wind-generated waves (GOW) and (ii) the meteorological sea level component (GOS). The GOW and GOS datasets cover the whole European coast (North Atlantic, North Sea, Baltic Sea, Mediterranean Sea and Black Sea) at high-spatial resolution from 1979 to present. The meteorological sea level component (storm surge) has been generated by the Regional Ocean Model System (ROMS). To take into account non-linear interactions between tides and surges, both dynamics were simulated jointly. Final results of meteorological component of sea level were obtained by subtracting the astronomical tide from the simulated sea surface. The model was set-up for Europe using an orthogonal grid, with a horizontal resolution ranging between 3.5 to 11 km. A spatial domain of approximately 5 km was used for the Black Sea. Local coastal waves can be the integrated result of the ocean surface over a large region of influence. GOW-Europe is designed from a multigrid approach based on the overlapping of two-way nested domains. The coarser spatial resolution along the European coast of GOW is 15 km. The generation and propagation of the sea surface waves of GOW-Europe are simulated with the model WAVEWATCH III v4.18. Effects of non-linear wave-wave interactions, whitecapping and depth-induced refraction are considered in the propagation model. In order to validate GOW and GOS over Europe with available observations, an exhaustive comparison with in-situ and remote measurements was developed. In-situ buoys and tide-gauges are used to compare hourly time

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

    NASA Astrophysics Data System (ADS)

    Bilgera, P. H. T.

    2015-12-01

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

  20. Self-Consistent Model of Magnetospheric Ring Current and Electromagnetic Ion Cyclotron Waves: The May 2-7, 1998, Storm

    NASA Technical Reports Server (NTRS)

    Khazanov, G. V.; Gamayunov, K. V.; Jordanova, V. K.

    2003-01-01

    Complete description of a self-consistent model for magnetospheric ring current interacting with electromagnetic ion cyclotron waves is presented. The model is based on the system of two kinetic equations; one equation describes the ring current ion dynamics, and another equation describes the wave evolution. The effects on ring current ions interacting with electromagnetic ion cyclotron waves, and back on waves, are considered self-consistently by solving both equations on a global magnetospheric scale under non steady-state conditions. In the paper by Khazanov et al. [2002] this self-consistent model has only been shortly outlined, and discussions of many the model related details have been omitted. For example, in present study for the first time a new algorithm for numerical finding of the resonant numbers for quasilinear wave-particle interaction is described, or it is demonstrated that in order to describe quasilinear interaction in a multi-ion thermal plasma correctly, both e and He(+) modes of electromagnetic ion cyclotron waves should be employed. The developed model is used to simulate the entire May 2-7, 1998 storm period. Trapped number fluxes of the ring current protons are calculated and presented along with their comparison with the data measured by the 3D hot plasma instrument Polar/HYDRA. Examining of the wave (MLT, L shell) distributions produced during the storm progress reveals an essential intensification of the wave emissions in about two days after main phase of storm. This result is well consistent with the earlier ground-based observations. Also the theoretical shapes and the occurrence rates for power spectral densities of electromagnetic ion cyclotron waves are studied. It is found that in about 2 days after the storm main phase on May 4, mainly non Gaussian shapes of power spectral densities are produced.

  1. Evidence for Gravity Wave Seeding of Convective Ionosphere Storms Initiated by Deep Troposphere Convection

    NASA Astrophysics Data System (ADS)

    Kelley, M. C.; Pfaff, R. F., Jr.; Dao, E. V.; Holzworth, R. H., II

    2014-12-01

    With the increase in solar activity, the Communications/Outage Forecast System satellite (C/NOFS) now goes below the F peak. As such, we now can study the development of Convective Ionospheric Storms (CIS) and, most importantly, large-scale seeding of the low growth-rate Rayleigh-Taylor (R-T) instability. Two mechanisms have been suggested for such seeding: the Collisional Kelvin-Helmholtz Instability (CKHI) and internal atmospheric gravity waves. A number of observations have shown that the spectrum of fully developed topside structures peaks at 600 km and extends to over 1000 km. These structures are exceedingly difficult to explain by CKHI. Here we show that sinusoidal plasma oscillations on the bottomside during daytime develop classical R-T structures on the nightside with the background 600 km structure still apparent. In two case studies, thunderstorm activity was observed east of the sinusoidal features in the two hours preceding the C/NOFS passes. Thus, we argue that convective tropospheric storms are a likely source of these sinusoidal features.

  2. EFFECTS OF ALFVEN WAVES ON ELECTRON CYCLOTRON MASER EMISSION IN CORONAL LOOPS AND SOLAR TYPE I RADIO STORMS

    SciTech Connect

    Zhao, G. Q.; Chen, L.; Wu, D. J.; Yan, Y. H.

    2013-06-10

    Solar type I radio storms are long-lived radio emissions from the solar atmosphere. It is believed that these type I storms are produced by energetic electrons trapped within a closed magnetic structure and are characterized by a high ordinary (O) mode polarization. However, the microphysical nature of these emissions is still an open problem. Recently, Wu et al. found that Alfven waves (AWs) can significantly influence the basic physics of wave-particle interactions by modifying the resonant condition. Taking the effects of AWs into account, this work investigates electron cyclotron maser emission driven by power-law energetic electrons with a low-energy cutoff distribution, which are trapped in coronal loops by closed solar magnetic fields. The results show that the emission is dominated by the O mode. It is proposed that this O mode emission may possibly be responsible for solar type I radio storms.

  3. Observations of ULF waves on the ground and ionospheric Doppler shifts during storm sudden commencement

    NASA Astrophysics Data System (ADS)

    Ouyang, Xinyan; Liu, Wenlong; Xiao, Zuo; Hao, Yongqiang

    2016-04-01

    Using data from ground-based magnetometers and HF Doppler sounder, we study ultralow frequency (ULF) waves excited during the storm sudden commencement (SSC) on 8 March 2012 and find possible evidence on the link between ULF waves and ionospheric Doppler shifts. Pc1-Pc2 ULF waves are observed from 11:04 to 11:27 UT after the SSC by ground stations of L shell ranging from 1.06 to 2.31, mapping to the topside ionosphere. There are weak responses in this frequency range in the power spectra of ionospheric Doppler shift. From 11:19 to 11:23 UT, oscillations of magnetic field in a lower frequency range of Pc3-Pc4 are observed and are well correlated with the trace of Doppler shift. It is thus suggested that ionospheric Doppler shift can response to ULF oscillations in magnetic field in various frequency ranges, especially in the frequency range of Pc3-Pc4 and below. This paper demonstrates a new mechanism of magnetosphere-ionosphere coupling.

  4. A New Look to Interactions of Saharan Dust with Waves in the Tropical Atlantic Storm Track

    NASA Astrophysics Data System (ADS)

    Hosseinpour, F.; Wilcox, E. M.; Colarco, P. R.

    2015-12-01

    This study addresses mechanisms of the interactions between light-absorbing aerosols and transient atmospheric waves, including their feedback onto the mean-circulation in one of the most meteorologically sensitive areas of the world: the tropical western African/eastern Atlantic Ocean. Evidence of these interactions are presented based on analyses of an ensemble of NASA satellite data sets, including aerosol optical thickness (AOT) observations from the Moderate Resolution Imaging Spectro-radiometer (MODIS) and the Sea-Viewing Wide Field-of-View Sensor (SeaWiFS), as well as an atmospheric reanalysis from the Modern-Era Retrospective Analysis for Research and Applications (MERRA) and a simulation of The Goddard Chemistry Aerosol Radiation and Transport (GOCART) model. We analyzed the components of the rate of change of eddy kinetic energy (EKE) to explore the possible role of dust aerosol radiative forcing on reinforcing energetic terms associated with the African easterly waves (AEWs) during boreal summer seasons when the activity of AEWs peaks. This study shows that the anomalous perturbations in concentration of dust in the oceanic Saharan Air Layer (OSAL) precede amplified growth and decay of the subsequent waves compared to waves occurring prior to dust outbreaks. The amplified EKE associated with dust outbreaks are followed by seeding of new wave packets through enhanced divergence and convergence of ageostrophic geopotential height fluxes in the tropical Atlantic storm track. Meanwhile, the enhanced forcing of the mean-circulation associated with the increased momentum fluxes of the high frequency eddies at the northern track of AEWs occurs with a time-lag after the peak of dust concentration in the OSAL. We suggest that dust radiative heating in the OSAL may act as an additional energy source to amplify the thermal/mechanical activity of eddies in the northern track of the AEWs.

  5. Character, distribution, and ecological significance of storm wave-induced scour in Rhode Island Sound, USA

    USGS Publications Warehouse

    McMullen, Katherine Y.; Poppe, Lawrence J.; Parker, Castle E.

    2015-01-01

    Multibeam bathymetry, collected during NOAA hydrographic surveys in 2008 and 2009, is coupled with USGS data from sampling and photographic stations to map the seabed morphology and composition of Rhode Island Sound along the US Atlantic coast, and to provide information on sediment transport and benthic habitats. Patchworks of scour depressions cover large areas on seaward-facing slopes and bathymetric highs in the sound. These depressions average 0.5-0.8 m deep and occur in water depths reaching as much as 42 m. They have relatively steep well-defined sides and coarser-grained floors, and vary strongly in shape, size, and configuration. Some individual scour depressions have apparently expanded to combine with adjacent depressions, forming larger eroded areas that commonly contain outliers of the original seafloor sediments. Where cobbles and scattered boulders are present on the depression floors, the muddy Holocene sands have been completely removed and the winnowed relict Pleistocene deposits exposed. Low tidal-current velocities and the lack of obstacle marks suggest that bidirectional tidal currents alone are not capable of forming these features. These depressions are formed and maintained under high-energy shelf conditions owing to repetitive cyclic loading imposed by high-amplitude, long-period, storm-driven waves that reduce the effective shear strength of the sediment, cause resuspension, and expose the suspended sediments to erosion by wind-driven and tidal currents. Because epifauna dominate on gravel floors of the depressions and infauna are prevalent in the finer-grained Holocene deposits, it is concluded that the resultant close juxtaposition of silty sand-, sand-, and gravel-dependent communities promotes regional faunal complexity. These findings expand on earlier interpretations, documenting how storm wave-induced scour produces sorted bedforms that control much of the benthic geologic and biologic diversity in Rhode Island Sound.

  6. Character, distribution, and ecological significance of storm wave-induced scour in Rhode Island Sound, USA

    NASA Astrophysics Data System (ADS)

    McMullen, Katherine Y.; Poppe, Lawrence J.; Parker, Castle E.

    2015-04-01

    Multibeam bathymetry, collected during NOAA hydrographic surveys in 2008 and 2009, is coupled with USGS data from sampling and photographic stations to map the seabed morphology and composition of Rhode Island Sound along the US Atlantic coast, and to provide information on sediment transport and benthic habitats. Patchworks of scour depressions cover large areas on seaward-facing slopes and bathymetric highs in the sound. These depressions average 0.5-0.8 m deep and occur in water depths reaching as much as 42 m. They have relatively steep well-defined sides and coarser-grained floors, and vary strongly in shape, size, and configuration. Some individual scour depressions have apparently expanded to combine with adjacent depressions, forming larger eroded areas that commonly contain outliers of the original seafloor sediments. Where cobbles and scattered boulders are present on the depression floors, the muddy Holocene sands have been completely removed and the winnowed relict Pleistocene deposits exposed. Low tidal-current velocities and the lack of obstacle marks suggest that bidirectional tidal currents alone are not capable of forming these features. These depressions are formed and maintained under high-energy shelf conditions owing to repetitive cyclic loading imposed by high-amplitude, long-period, storm-driven waves that reduce the effective shear strength of the sediment, cause resuspension, and expose the suspended sediments to erosion by wind-driven and tidal currents. Because epifauna dominate on gravel floors of the depressions and infauna are prevalent in the finer-grained Holocene deposits, it is concluded that the resultant close juxtaposition of silty sand-, sand-, and gravel-dependent communities promotes regional faunal complexity. These findings expand on earlier interpretations, documenting how storm wave-induced scour produces sorted bedforms that control much of the benthic geologic and biologic diversity in Rhode Island Sound.

  7. Storm-time fingerprints of Pc 4-5 waves on energetic electron flux at geosynchronous orbit

    NASA Astrophysics Data System (ADS)

    Georgiou, Marina; Daglis, Ioannis A.; Zesta, Eftyhia; Balasis, George; Mann, Ian R.; Tsinganos, Kanaris

    2014-05-01

    Geospace magnetic storms, associated with either coronal mass ejections (CMEs) or high speed solar streams, involve global variations of the geomagnetic field as well as acceleration of charged particles in the magnetosphere. Ultra low frequency (ULF) waves with frequencies in the range of a few mHz (Pc 4-5 waves) can be generated externally by compressive variations in the solar wind or shear flow along the magnetopause unstable to the Kelvin-Helmholtz effect. Furthermore, low frequency instabilities of ring current ions are also considered as a possible internal driver of ULF wave growth. We examine power enhancements of ULF waves during four successive magnetic storms, which occurred in July 2004 and were characterized by a decreasing minimum of the Dst index, from -76 nT down to -197 nT. During the course of the magnetic storms, ULF wave power variations have been observed nearly simultaneously at different magnetic latitudes and longitudes by the ground-based CARISMA, IMAGE, 210 MM and SAMBA magnetometer networks. Nonetheless, stronger magnetic storms were accompanied by greater ULF wave power enhancements tending to be more pronounced at magnetic stations located at lower L shells. Furthermore, the generation and penetration of ULF wave power deep into the inner magnetosphere seems to be contributing to the energization and transport of relativistic electrons. Except for the magnetic storm on 25 July 2000, the three magnetic storms on 17, 23 and 27 July 2004 were characterized by a significant increase in the flux of electrons with energies higher than 1 MeV, as measured by GOES-10 and -12 during the recovery phase of each storm. On the other hand, when looking at the magnetic storm on 17 August 2001, the initial decrease was followed by an increase six days after the commencement of the storm. The electron flux decrease was more than two orders of magnitude and remained low after the recovery of the Dst index. These observations provided us the basis for

  8. Quantification of abnormal intracranial pressure waves and isotope cisternography for diagnosis of occult communicating hydrocephalus

    SciTech Connect

    Cardoso, E.R.; Piatek, D.; Del Bigio, M.R.; Stambrook, M.; Sutherland, J.B.

    1989-01-01

    Nineteen consecutive patients with suspected occult communicating hydrocephalus were investigated by means of clinical evaluation, neuropsychological testing, isotope cisternography, computed tomography scanning, and continuous intracranial pressure monitoring. Semi-quantitative grading systems were used in the evaluation of the clinical, neuropsychological, and cisternographic assessments. Clinical examination, neuropsychological testing, and computed tomography scanning were repeated 3 months after ventriculoperitoneal shunting. All patients showed abnormal intracranial pressure waves and all improved after shunting. There was close correlation between number, peak, and pulse pressures of B waves and the mean intracranial pressure. However, quantification of B waves by means of number, frequency, and amplitude did not help in predicting the degree of clinical improvement postshunting. The most sensitive predictor of favorable response to shunting was enlargement of the temporal horns on computed tomography scan. Furthermore, the size of temporal horns correlated with mean intracranial pressure. There was no correlation between abnormalities on isotope cisternography and clinical improvement.

  9. Earthward penetration of Pc 4-5 waves and radiation belt electron enhancements during geospace magnetic storms

    NASA Astrophysics Data System (ADS)

    Daglis, I. A.; Georgiou, M.; Zesta, E.; Balasis, G.; Tsinganos, K.

    2013-12-01

    This paper addresses the question whether radiation belt electron enhancements are associated with ultra-low frequency (ULF) wave power penetrating to lower L-shells during intense geospace magnetic storms. We have examined the variation of relativistic electron fluxes in the inner magnetosphere during small, moderate, and intense storms and have compared them with concurrent variations of the power of Pc 4-5 waves, using multi-point wave observations from the IMAGE and CARISMA ground-based magnetometer arrays. We discuss the excitation, growth and decay characteristics of Pc 4-5 waves during the different phases of the three classes of magnetic storms, with particular emphasis on the distribution of wave power over a range of L shells. The work leading to this paper has received funding from the European Union's Seventh Framework Programme (FP7-SPACE-2011-1) under grant agreement no. 284520 for the MAARBLE (Monitoring, Analyzing and Assessing Radiation Belt Energization and Loss) collaborative research project.

  10. Estimating the Power per Mode Number and Power vs L-shell of Broadband, Storm-time ULF Waves

    NASA Astrophysics Data System (ADS)

    Sarris, T. E.; Li, X.; Liu, W.; Argyriadis, E.

    2013-12-01

    In studies of particles' radial diffusion processes in the magnetosphere it is well known that Ultra-Low Frequency (ULF) waves of frequency m*ωd can resonantly interact with particles of drift frequency ωd, where m is the azimuthal mode number of the waves; however due to difficulties in estimating m an over-simplifying assumption is often made in radial diffusion simulations, namely that all ULF wave power is located at m=1 or, in some cases, m=2. In another assumption that is commonly made, power measured from geosynchronous satellites is assumed to be uniform across L-shells. In the present work, a technique is presented for extracting information on the distribution of ULF wave power in a range of azimuthal mode numbers, through calculations of the cross-power and phase differences between a number of azimuthally aligned pairs of magnetometers, either in space or on the ground. We find that the temporal evolution of power at each mode number gives unique insight into the temporal evolution of ULF waves during a storm as well as a more accurate characterization of broadband ULF waves. Furthermore, using multi-spacecraft measurements during a particular storm, we calculate the L-dependence of ULF wave power. These measurements and calculations can be used in more accurate ULF wave representation in radial diffusion simulations.

  11. Coupled atmosphere-ocean-wave simulations of a storm event over the Gulf of Lion and Balearic Sea

    USGS Publications Warehouse

    Renault, Lionel; Chiggiato, Jacopo; Warner, John C.; Gomez, Marta; Vizoso, Guillermo; Tintore, Joaquin

    2012-01-01

    The coastal areas of the North-Western Mediterranean Sea are one of the most challenging places for ocean forecasting. This region is exposed to severe storms events that are of short duration. During these events, significant air-sea interactions, strong winds and large sea-state can have catastrophic consequences in the coastal areas. To investigate these air-sea interactions and the oceanic response to such events, we implemented the Coupled Ocean-Atmosphere-Wave-Sediment Transport Modeling System simulating a severe storm in the Mediterranean Sea that occurred in May 2010. During this event, wind speed reached up to 25 m.s-1 inducing significant sea surface cooling (up to 2°C) over the Gulf of Lion (GoL) and along the storm track, and generating surface waves with a significant height of 6 m. It is shown that the event, associated with a cyclogenesis between the Balearic Islands and the GoL, is relatively well reproduced by the coupled system. A surface heat budget analysis showed that ocean vertical mixing was a major contributor to the cooling tendency along the storm track and in the GoL where turbulent heat fluxes also played an important role. Sensitivity experiments on the ocean-atmosphere coupling suggested that the coupled system is sensitive to the momentum flux parameterization as well as air-sea and air-wave coupling. Comparisons with available atmospheric and oceanic observations showed that the use of the fully coupled system provides the most skillful simulation, illustrating the benefit of using a fully coupled ocean-atmosphere-wave model for the assessment of these storm events.

  12. Tropical and extratropical-origin storm wave types and their influence on the East Australian longshore sand transport system under a changing climate

    NASA Astrophysics Data System (ADS)

    Goodwin, Ian D.; Mortlock, Thomas R.; Browning, Stuart

    2016-07-01

    Tropical expansion is potentially an amplifier of coastal change in the subtropics, through directional wave climate shifts. The storm wave climate and directional wave power distribution along the Southeast Australian Shelf (SEAS) is investigated with respect to tropical extent. Forty years of storm wave observations from nine midshelf wave buoys are evaluated using synoptic storm wave typing. A robust latitudinal and along-shelf gradient in storm wave types and wave propagation patterns exists. The tropical origin storms produce a shore-normal propagation pattern along the SEAS, reduce the connectivity of coastal compartments through minor headland bypassing events or episodically reversing the net northward transport. In contrast, the extratropical origin storms produce a shore-oblique propagation pattern from the Southern Tasman to the Coral Sea, and are an important control on the connectivity of regional longshore sand transport through episodic major headland bypassing events between compartments, and the maintenance of down-drift coastlines in dynamic equilibrium. Future climate change projections indicate that the recent trend in the expansion of the latitudinal extent of the tropics in the south-west Pacific region will continue throughout this century. The combined impacts of a projected 2.5° poleward shift on the storm wave climate is a significant reduction in net northward longshore sand transport and the efficiency of headland bypassing events. On the North and Central Coasts of New South Wales we project a ˜30% reduction in longshore sand transport for the dominant extratropical-origin storm events, together with a ˜5% increase in reversed (net southward) longshore sand transport for tropical-origin storm events.

  13. ULF waves and radiation belts: earthward penetration of Pc 4-5 waves and energetic electron flux enhancements during geospace magnetic storms

    NASA Astrophysics Data System (ADS)

    Georgiou, Marina; Daglis, Ioannis; Zesta, Eftyhia; Balasis, George; Tsinganos, Kanaris

    2013-04-01

    Energetic particle fluxes in the outer radiation belt can vary over orders of magnitude on time scales ranging from minutes, to days and years. Geospace magnetic storms when sufficiently strong to exceed key thresholds of the Dst index may either increase or decrease the fluxes of energetic electrons. We examine the responses of energetic electrons to nine moderate, intense and weak magnetic storms, which occurred at different phases of the solar cycle, and compare these with concurrent variations of ULF wave power. Pc 4-5 waves with frequencies in the range of a few mHz may be generated internally in the magnetosphere by low frequency instabilities of ring current ions and externally by shear instabilities at the magnetopause flanks, or compressive variations in the solar wind. Here, we present multipoint observations from ground-based magnetometer arrays collocated with electron drift orbits, which are complemented and measurements by conjugate multi-point satellites, such as CHAMP, Cluster, GOES and THEMIS. We discuss the excitation, growth and decay characteristics of Pc 4-5 waves during the different phases of the magnetic storms with particular emphasis on the distribution of Pc 4-5 wave power over a variety of L shells. We investigate whether Pc 4-5 wave power penetrates to lower L shell values during periods of relatively intense geomagnetic activity as compared to weak magnetic storms. Structural changes of the magnetosphere during intense geomagnetic storms can play an important role in the generation and penetration of Pc 4-5 waves deep into the inner magnetosphere, which in turn is of significance for the wave-particle interactions contributing to the acceleration, transport and loss of electrons in the outer radiation belt. We present preliminary statistics of Pc 4-5 waves observed during magnetic storms of varying intensity, which occurred over the course of the previous solar cycle. This work is supported by the European Community's Seventh Framework

  14. ON THE BRIGHTNESS AND WAITING-TIME DISTRIBUTIONS OF A TYPE III RADIO STORM OBSERVED BY STEREO/WAVES

    SciTech Connect

    Eastwood, J. P.; Hudson, H. S.; Krucker, S.; Bale, S. D.; Wheatland, M. S.; Maksimovic, M.; Bougeret, J.-L.; Goetz, K.

    2010-01-10

    Type III solar radio storms, observed at frequencies below {approx}16 MHz by space-borne radio experiments, correspond to the quasi-continuous, bursty emission of electron beams onto open field lines above active regions. The mechanisms by which a storm can persist in some cases for more than a solar rotation whilst exhibiting considerable radio activity are poorly understood. To address this issue, the statistical properties of a type III storm observed by the STEREO/WAVES radio experiment are presented, examining both the brightness distribution and (for the first time) the waiting-time distribution (WTD). Single power-law behavior is observed in the number distribution as a function of brightness; the power-law index is {approx}2.1 and is largely independent of frequency. The WTD is found to be consistent with a piecewise-constant Poisson process. This indicates that during the storm individual type III bursts occur independently and suggests that the storm dynamics are consistent with avalanche-type behavior in the underlying active region.

  15. A modeling study of the impact of major storms on waves, surface and near-bed currents on the Grand Banks of Newfoundland

    NASA Astrophysics Data System (ADS)

    Li, Michael Z.; Wu, Yongsheng; Prescott, Robert H.; Tang, Charles C. L.; Han, Guoqi

    2015-08-01

    Waves and current processes, both surface and near-bed were simulated for major storms on the Grand Banks of Newfoundland using integrated wave, 3-D tidal and ocean current models. Most storms track southwest to northeast and pass to the north or northwest of the Grand Banks. Significant wave heights can reach up to ˜14 m and are predominantly to the northeast at the peak of storms. Extreme surface currents reach approximately 1 m s-1 and are largely to the southeast. The strongest bottom currents, up to 0.8 m s-1, occur on St. Pierre Bank and are dominantly to the south and southeast. While wave height and wind-driven current generally increase with wind speed, factors such as storm paths, the relative location of the storm center at the storm peak, and storm translation speed also affect waves and currents. Surface and near-bed wind-driven currents both rotate clockwise and decrease in strength as the storm traverses the Grand Banks. While the spatial variability of the storm impact on surface currents is relatively small, bottom currents show significant spatial variation of magnitude and direction as well as timing of peak current conditions. These spatial variations are controlled by the changes of bathymetry and mixed layer depth over the model domain. The storm-generated currents can be 7 to 10 times stronger than the background mean currents. These strong currents interact with wave oscillatory flows to produce shear velocities up to 15 cm s-1 and cause wide occurrences of strong sediment transport over nearly the entire Grand Banks.

  16. Association of radiation belt electron enhancements with earthward penetration of Pc5 ULF waves: a case study of intense 2001 magnetic storms

    NASA Astrophysics Data System (ADS)

    Georgiou, M.; Daglis, I. A.; Zesta, E.; Balasis, G.; Mann, I. R.; Katsavrias, C.; Tsinganos, K.

    2015-11-01

    Geospace magnetic storms, driven by the solar wind, are associated with increases or decreases in the fluxes of relativistic electrons in the outer radiation belt. We examine the response of relativistic electrons to four intense magnetic storms, during which the minimum of the Dst index ranged from -105 to -387 nT, and compare these with concurrent observations of ultra-low-frequency (ULF) waves from the trans-Scandinavian IMAGE magnetometer network and stations from multiple magnetometer arrays available through the worldwide SuperMAG collaboration. The latitudinal and global distribution of Pc5 wave power is examined to determine how deep into the magnetosphere these waves penetrate. We then investigate the role of Pc5 wave activity deep in the magnetosphere in enhancements of radiation belt electrons population observed in the recovery phase of the magnetic storms. We show that, during magnetic storms characterized by increased post-storm electron fluxes as compared to their pre-storm values, the earthward shift of peak and inner boundary of the outer electron radiation belt follows the Pc5 wave activity, reaching L shells as low as 3-4. In contrast, the one magnetic storm characterized by irreversible loss of electrons was related to limited Pc5 wave activity that was not intensified at low L shells. These observations demonstrate that enhanced Pc5 ULF wave activity penetrating deep into the magnetosphere during the main and recovery phase of magnetic storms can, for the cases examined, distinguish storms that resulted in increases in relativistic electron fluxes in the outer radiation belts from those that did not.

  17. MESSENGER survey of in situ low frequency wave storms between 0.3 and 0.7 AU

    NASA Astrophysics Data System (ADS)

    Boardsen, S. A.; Jian, L. K.; Raines, J. L.; Gershman, D. J.; Zurbuchen, T. H.; Roberts, D. A.; Korth, H.

    2015-12-01

    MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) magnetometer data was surveyed between 0.3 and 0.7 AU from 6 June 2007 to 23 March 2011 for low-frequency wave (LFW) storms, when the magnetometer was sampling at a rate of at least 2 s-1. A total of 12,197 LFW events were identified, of which 5506 lasted 10 min or longer. The events have a high degree of polarization, are circularly polarized, with wave vectors nearly aligned or antialigned with the interplanetary magnetic field (IMF) at frequencies in the vicinity of the proton cyclotron frequency. These events are observed about 6% of the time, preferentially associated with radially directed inward or outward IMF. Their occurrence rate and median duration do not change much with R, where R is the heliocentric radial distance. For a narrow-frequency window in the solar wind frame, left-handed storms in the spacecraft frame have a power drop off that is roughly proportional to R-3 which is consistent with a source close the Sun, while right-handed storms have a power drop off roughly proportional R-1 which is not consistent with a source close to the Sun. The power in the left-handed LFW storms is on average greater than the right-handed ones by a factor of 3. In the solar wind frame, the wave frequency decreases from 0.13 to 0.04 Hz moving from 0.3 to 0.7 AU, but the frequency normalized by the local proton cyclotron frequency does not change much with the running median varying from 0.35 to 0.5. The normalized frequency band widths of the wave power spectra increase slightly with R, possibly associated with energy dissipation.

  18. Forced regressions in a large wave- and storm-dominated anoxic lake, Rhaetian-Sinemurian Kap Stewart Formation, East Greenland

    SciTech Connect

    Dam, G. ); Surlyk, F. )

    1992-08-01

    During Rhaetian-Sinemurian time a large wave- and storm-dominated lake was situated in the Jameson Land basin, East Greenland. Lake deposits consist of alternating black unfossiliferous mudstones and sheet sandstones. Anoxic conditions dominated at the lake bottom during deposition of the muds, and the water column was probably stratified. The sandstones were deposited by progradation of wave- and storm-dominated deltas in a water depth of less than 15 m. Sequence-stratigraphic interpretation suggests that the mudstones were deposited in periods of rising and very high stands of lake level, whereas progradation of the deltaic sheet sandstones took place during forced regressions caused by significant falls. The lake thus underwent a large number of fairly high amplitude changes in level, probably caused by climatic fluctuations. The high-order cycles can be grouped into several long-period cycles that show the same number of major fluctuations as published eustatic sea-level curves. This similarity suggests a causal link between eustasy and long-period variations in the lake. The Kap Stewart Formation represents one of the few ancient examples of a large wave- and storm-dominated lake, and it is probably the first documented case of abundant well-developed lacustrine forced regressions.

  19. Gulf of Mexico hydrocarbon seep communities. V. Biofacies and shell orientation of autochthonous shell beds below storm wave base

    SciTech Connect

    Callender, W.R.; Staff, G.M.; Powell, E.N.; MacDonald, I.R. )

    1990-02-01

    Clam and mussel assemblages associated with petroleum seepage on the Louisiana continental slope form the only substantial shell accumulations below storm wave base on the northwestern Gulf of Mexico shelf and slope. Four distinct biofacies are present at the seeps, dominated respectively by mussels, lucinid clams, vesicomyid clams and tubeworms. Each primary seep site is typically composed of a series of not necessarily contiguous, autochthonous beds dominated by one biofacies. Mussels and tubeworms often co-occur, but neither normally co-occur with lucinid or vesicomyid clams. Lucinid and vesicomyid clam beds have the best chance of preservation. Despite essentially undisturbed accumulation in quiet water below storm wave base, concavity ratios rarely differ from 1:1 and frequency of articulation may be low. Dominantly concave-up valves previously reported in quiet water may result from man's fishing activities. Significant variability in shell orientation, frequency of articulation and concavity ratio between adjacent samples indicates that many individual stratigraphically-equivalent samples should be used in any taphofacies analysis of assemblages formed in low-energy environments. Lucinid beds which form below the sediment surface and vesicomyid beds which form on the sediment surface differed significantly in shell orientation and articulation frequency. Assemblages forming below storm wave base in low-energy environments may comprise a wide variety of taphofacies depending upon whether formation occurs primarily beneath the sediment surface or on the sediment surface, despite contemporaneous formation under similar environmental conditions.

  20. Data and numerical analysis of astronomic tides, wind-waves, and hurricane storm surge along the northern Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Bilskie, M. V.; Hagen, S. C.; Medeiros, S. C.; Cox, A. T.; Salisbury, M.; Coggin, D.

    2016-05-01

    The northern Gulf of Mexico (NGOM) is a unique geophysical setting for complex tropical storm-induced hydrodynamic processes that occur across a variety of spatial and temporal scales. Each hurricane includes its own distinctive characteristics and can cause unique and devastating storm surge when it strikes within the intricate geometric setting of the NGOM. While a number of studies have explored hurricane storm surge in the NGOM, few have attempted to describe storm surge and coastal inundation using observed data in conjunction with a single large-domain high-resolution numerical model. To better understand the oceanic and nearshore response to these tropical cyclones, we provide a detailed assessment, based on field measurements and numerical simulation, of the evolution of wind waves, water levels, and currents for Hurricanes Ivan (2004), Dennis (2005), Katrina (2005), and Isaac (2012), with focus on Mississippi, Alabama, and the Florida Panhandle coasts. The developed NGOM3 computational model describes the hydraulic connectivity among the various inlet and bay systems, Gulf Intracoastal Waterway, coastal rivers and adjacent marsh, and built infrastructure along the coastal floodplain. The outcome is a better understanding of the storm surge generating mechanisms and interactions among hurricane characteristics and the NGOM's geophysical configuration. The numerical analysis and observed data explain the ˜2 m/s hurricane-induced geostrophic currents across the continental shelf, a 6 m/s outflow current during Ivan, the hurricane-induced coastal Kelvin wave along the shelf, and for the first time a wealth of measured data and a detailed numerical simulation was performed and was presented for Isaac.

  1. Study of Ardmore, Oklahoma storm clouds. I - Convective storm cloud initiation and development based on the remote sensing gravity-wave-induced convection. II - Satellite infrared remote sensing and numerical simulation

    NASA Technical Reports Server (NTRS)

    Hung, R. J.; Tsao, Y. D.

    1991-01-01

    The role of gravity waves is discussed with respect to the vertical velocity of convection. Specific attention is given to wave-induced convection which contributes to the fractions of formation and the development of severe convective storms. Large-amplitude gravity waves and convective instability were investigated in storm clouds above Ardmore, Oklahoma. Rapid-scan satellite imagery and radar summaries provide evidence of water-vapor condensation related to convection which is introduced by gravity waves. Gravity wave periods of 35 minutes are found to initiate weak convection, which can be intensified by gravity waves with periods of 20 minutes. The convective motion reaches a maximum about one hour before funnel clouds develop. Other mechanisms which contribute to convective motion are considered, but gravity waves are the major contributor to the initiation, formation, and development of mesoscale storm clouds. Cloud modeling based on satellite imagery and sounding data showed that by overshooting cloud tops that penetrated the tropopause, storm clouds mature; that these clouds collapse about 9 minutes before the touchdown of tornadoes; and that cloud tops collapse at a high rate about 6 minutes before tornadoes lift off.

  2. Storms or cold fronts? What is really responsible for the extreme waves regime in the Colombian Caribbean coast

    NASA Astrophysics Data System (ADS)

    Otero, L. J.; Ortiz-Royero, J. C.; Ruiz-Merchan, J. K.; Higgins, A. E.; Henriquez, S. A.

    2015-05-01

    On Friday, 7 March 2009, a 200 m-long section of the tourist pier in Puerto Colombia collapsed under the impact of the waves generated by a cold front in the area. The aim of this study is to determine the contribution and importance of cold fronts and storms on extreme waves in different areas of the Colombian Caribbean to determine the degree of the threat posed by the flood processes to which these coastal populations are exposed and the actions to which coastal engineering constructions should be subject. In the calculation of maritime constructions, the most important parameter is the wave's height; therefore, it is necessary to definitively know the design wave height to which a coastal engineering structure should be resistant. This wave height varies according to the return period considered. Using Gumbel's extreme value methodology, the significant height values for the study area were calculated. The methodology was evaluated using data from the re-analysis of the spectral NOAA Wavewatch III (WW3) model for 15 points along the 1600 km of the Colombia Caribbean coast (continental and insular) of the last 15 years. The results demonstrated that the extreme waves caused by tropical cyclones and cold fronts have different effects along the Colombian Caribbean coast. Storms and hurricanes are of greater importance in the Guajira Peninsula (Alta Guajira). In the central area formed by Baja Guajira, Santa Marta, Barranquilla, and Cartagena, the strong influence of cold fronts on extreme waves is evident. On the other hand, in the southern region of the Colombian Caribbean coast, from the Gulf of Morrosquillo to the Gulf of Urabá, even though extreme waves are lower than in the previous regions, extreme waves are dominated mainly by the passage of cold fronts. Extreme waves in the San Andrés and Providencia insular region present a different dynamic from that in the continental area due to its geographic location. The wave heights in the extreme regime are

  3. Past analogs of recent climate anomalies and impacts in Portugal. Droughts, storms and heat waves

    NASA Astrophysics Data System (ADS)

    Alcoforado, M. J.; Nunes, M. F.

    2009-09-01

    An indexed reconstruction of precipitation variability, based on documentary and instrumental data, has been done for southern Portugal starting in 1675. The descriptions of the extreme events in the documentary sources have also supplied information about their impacts. We will compare past and recent extreme weather events in Portugal, their causes and their impacts on society. We have selected periods of winter droughts, of storms that triggered great floods and of heat waves. There are a number of documentary sources dating from 1693-94 indicating that that there was no rainfall from December 1693 to at least November 1694 with the exception of light showers in June. Several pro-pluvia rogations ceremonies took place all over the country, even in the Northwest that is generally rainy. There are numerous descriptions of the impact of droughts on agriculture, of shortage of cereals, of escalating prices and the subsequent generalised famine. An analogy will be made for the 20th century using the 1980-81 winter drought that lasted roughly the same time and which also had severe social and economic impacts. The decrease in production of hydroelectric energy (50% below average) between January and July 1981 is also pointed out. In both cases, the lack of rainfall was partly due to a ridge that stayed over the Eastern Atlantic and kept Iberia in aerologic shelter. Apart from urban flash floods there are two types of floods in Portugal: (i) floods from the big river basins (Tagus, Mondego and Douro) that are due to the frequent passage of westerly frontal depressions during days or weeks; and (ii) floods of the small river basins due to convective depressions that affect small areas. The December 1739 flood, caused by the overflow of the great rivers, will be compared with the ones that occurred in February 1978. Both were caused by intensive precipitation all over the country at a time when the soil was already saturated with water from previous rainfall. The damages

  4. Comparison of diagnostic accuracy, time dependency, and prognostic impact of abnormal Q waves, combined electrocardiographic criteria, and ST segment abnormalities in right ventricular infarction.

    PubMed Central

    Zehender, M; Kasper, W; Kauder, E; Schönthaler, M; Olschewski, M; Just, H

    1994-01-01

    OBJECTIVE--To determine the diagnostic and prognostic impact of abnormal Q waves in comparison to or in combination with ST segment abnormalities in the right precordial and inferior leads as indicators of right ventricular infarction during the acute phase of inferior myocardial infarction. DESIGN--Prospective study of a consecutive series of 200 patients with acute inferior myocardial infarction with and without right ventricular infarction. SETTING--Department of internal medicine, university clinic. RESULTS--Right ventricular infarction was diagnosed in 106 (57%) out of 187 patients from the results of coronary angiography, technetium pyrophosphate scanning, and measurement of haemodynamic variables or at necropsy, or both. In the acute phase of inferior infarction ST segment elevation > or = 0.1 mV in any of the right precordial leads V4-6R was the most reliable criterion for right ventricular infarction (sensitivity, 89%; specificity, 83%). Abnormal Q waves in the right precordial leads, the most specific criterion (91%) for right ventricular infarction, were superior to ST segment elevation in patients admitted > 12 hours after the onset of symptoms. Both ST segment elevation in leads V4-6R (increase in in hospital mortality, 6.2-times; P < 0.001; major complications, 2.3-times; P < 0.01) and abnormal Q waves (2.3-times, P < 0.05; 1.8-times, P < 0.05) on admission were highly predictive of a worse outcome during the in hospital period. In the presence of inferior myocardial infarction previously proposed combined electrocardiographic criteria were not better diagnostically or prognostically than ST segment abnormalities and abnormal Q waves alone. CONCLUSIONS--During the first 24 hours of inferior myocardial infarction ST segment elevation and abnormal Q waves derived from the right precordial leads are complementary rather than competitive criteria for reliably diagnosing right ventricular infarction, both indicating a worse in hospital course for the

  5. Coarse, Intermediate and High Resolution Numerical Simulations of the Transition of a Tropical Wave Critical Layer to a Tropical Storm

    NASA Technical Reports Server (NTRS)

    Montgomery, M. T.; Dunkerton, T. J.; Wang, Z.

    2010-01-01

    Recent work has hypothesized that tropical cyclones in the deep Atlantic and eastern Pacific basins develop from within the cyclonic Kelvin cat's eye of a tropical easterly wave critical layer located equatorward of the easterly jet axis. The cyclonic critical layer is thought to be important to tropical cyclogenesis because its cat's eye provides (i) a region of cyclonic vorticity and weak deformation by the resolved flow, (ii) containment of moisture entrained by the developing flow and/or lofted by deep convection therein, (iii) confinement of mesoscale vortex aggregation, (iv) a predominantly convective type of heating profile, and (v) maintenance or enhancement of the parent wave until the developing proto-vortex becomes a self-sustaining entity and emerges from the wave as a tropical depression. This genesis sequence and the overarching framework for describing how such hybrid wave-vortex structures become tropical depressions/storms is likened to the development of a marsupial infant in its mother's pouch, and for this reason has been dubbed the "marsupial paradigm". Here we conduct the first multi-scale test of the marsupial paradigm in an idealized setting by revisiting the Kurihara and Tuleya problem examining the transformation of an easterly wave-like disturbance into a tropical storm vortex using the WRF model. An analysis of the evolving winds, equivalent potential temperature, and relative vertical vorticity is presented from coarse (28 km), intermediate (9 km) and high resolution (3.1 km) simulations. The results are found to support key elements of the marsupial paradigm by demonstrating the existence of rotationally dominant region with minimal strain/shear deformation near the center of the critical layer pouch that contains strong cyclonic vorticity and high saturation fraction. This localized region within the pouch serves as the "attractor" for an upscale "bottom up" development process while the wave pouch and proto-vortex move together.

  6. RAM-SCB Simulations of Electron Transport and Plasma Wave Scattering During the October 2012 double-dip Storm

    NASA Astrophysics Data System (ADS)

    Jordanova, V.

    2015-12-01

    The mechanisms for particle injection in the near-Earth space environment and their subsequent trapping or loss have been studied for many years, however, their theoretical evaluation and implementation in numerical models remain challenging. We address these outstanding questions using our RAM-SCB model that couples the kinetic ring current-atmosphere interactions model with an Euler potential-based three-dimensional plasma equilibrium code. We simulate wave-particle interactions on a global scale using L and MLT-dependent event-specific wave models and investigate the fast dropout of the radiation belts during the October 2012 "double-dip" storm event. The calculated cold plasma densities with a coupled time-dependent 2-D plasmasphere model show good agreement with in situ EMFISIS observations along the Van Allen Probes' orbits. The simulated with RAM-SCB precipitating electron fluxes are compared with measurements of electron precipitation by multiple NOAA satellites during the investigated storm event. The combined effects from radial transport and scattering by plasma waves on ring current and radiation belt dynamics are evaluated.

  7. Mean flow-storm track relationship and Rossby wave breaking in two types of El-Niño

    NASA Astrophysics Data System (ADS)

    Liu, Chengji; Ren, Xuejuan; Yang, Xiuqun

    2014-01-01

    The features of large-scale circulation, storm tracks and the dynamical relationship between them were examined by investigating Rossby wave breaking (RWB) processes associated with Eastern Pacific (EP) and Central Pacific (CP) El-Niño. During EP El-Niño, the geopotential height anomaly at 500 hPa (Z500) exhibits a Pacific-North America (PNA) pattern. During CP El-Niño, the Z500 anomaly shows a north positive-south negative pattern over the North Pacific. The anomalous distributions of baroclinicity and storm track are consistent with those of upper-level zonal wind for both EP and CP El-Niño, suggesting impacts of mean flow on storm track variability. Anticyclonic wave breaking (AWB) occurs less frequently in EP El-Niño years, while cyclonic wave breaking (CWB) occurs more frequently in CP El-Niño years over the North Pacific sector. Outside the North Pacific, more CWB events occur over North America during EP El-Niño. When AWB events occur less frequently over the North Pacific during EP El-Niño, Z500 decreases locally and the zonal wind is strengthened (weakened) to the south (north). This is because AWB events reflect a monopole high anomaly at the centroid of breaking events. When CWB events occur more frequently over the North Pacific under CP El-Niño conditions, and over North America under EP El-Niño condition, Z500 increases (decreases) to the northeast (southwest), since CWB events are related to a northeast-southwest dipole Z500 anomaly. The anomalous RWB events act to invigorate and reinforce the circulation anomalies over the North Pacific-North America region linked with the two types of El-Niño.

  8. Storms or cold fronts: what is really responsible for the extreme waves regime in the Colombian Caribbean coastal region?

    NASA Astrophysics Data System (ADS)

    Otero, L. J.; Ortiz-Royero, J. C.; Ruiz-Merchan, J. K.; Higgins, A. E.; Henriquez, S. A.

    2016-02-01

    The aim of this study is to determine the contribution and importance of cold fronts and storms to extreme waves in different areas of the Colombian Caribbean in an attempt to determine the extent of the threat posed by the flood processes to which these coastal populations are exposed. Furthermore, the study wishes to establish the actions to which coastal engineering constructions should be subject. In the calculation of maritime constructions, the most important parameter is the height of the wave. For this reason, it is necessary to establish the design wave height to which a coastal engineering structure should be resistant. This wave height varies according to the return period considered. The significant height values for the areas focused on in the study were calculated in accordance with Gumbel's extreme value methodology. The methodology was evaluated using data from the reanalysis of the spectral National Oceanic and Atmospheric Administration (NOAA) WAVEWATCH III® (WW3) model for 15 points along the 1600 km of the Colombian Caribbean coastline (continental and insular) between the years 1979 and 2009. The results demonstrated that the extreme waves caused by tropical cyclones and those caused by cold fronts have different effects along the Colombian Caribbean coast. Storms and hurricanes are of greater importance in the Guajira Peninsula (Alta Guajira). In the central area (consisting of Baja Guajira, and the cities of Santa Marta, Barranquilla, and Cartagena), the strong impact of cold fronts on extreme waves is evident. However, in the southern region of the Colombian Caribbean coast (ranging from the Gulf of Morrosquillo to the Gulf of Urabá), the extreme values of wave heights are lower than in the previously mentioned regions, despite being dominated mainly by the passage of cold fronts. Extreme waves in the San Andrés and Providencia insular region present a different dynamic from

  9. A case study of winter storm-induced continental shelf waves in the northern South China Sea in winter 2009

    NASA Astrophysics Data System (ADS)

    Li, Junyi; Zheng, Quanan; Hu, Jianyu; Xie, Lingling; Zhu, Jia; Fan, Zhenhua

    2016-08-01

    This study deals with winter storm-induced continental shelf waves (CSWs) in the northern South China Sea in winter 2009 using tidal gauge data and along-track satellite altimeter data. The results show that the periods of CSWs propagating along the coast from Kanmen to Shuidong are in bands of 62 and 133 h. The phase speeds are in a range from 8 to 13 m s-1 between Kanmen and Shantou, from 9 to 11 m s-1 between Shantou and Huizhou and from 10 to 15 m s-1 between Huizhou and Shuidong, respectively. Satellite altimeter captured along-track sea level anomaly during the CSW events. Further analysis using the theoretical cross-shore CSW modes to fit the along-track sea level anomaly data indicates that the first three wave modes play important roles during the CSW events and the first mode is a dominant component.

  10. Van Allen Probes observations of unusually low frequency whistler mode waves observed in association with moderate magnetic storms: Statistical study

    PubMed Central

    Breneman, A. W.; Thaller, S. A.; Wygant, J. R.; Kletzing, C. A.; Kurth, W. S.

    2015-01-01

    Abstract We show the first evidence for locally excited chorus at frequencies below 0.1 f ce (electron cyclotron frequency) in the outer radiation belt. A statistical study of chorus during geomagnetic storms observed by the Van Allen Probes found that frequencies are often dramatically lower than expected. The frequency at peak power suddenly stops tracking the equatorial 0.5 f ce and f/f ce decreases rapidly, often to frequencies well below 0.1 f ce (in situ and mapped to equator). These very low frequency waves are observed both when the satellites are close to the equatorial plane and at higher magnetic latitudes. Poynting flux is consistent with generation at the equator. Wave amplitudes can be up to 20 to 40 mV/m and 2 to 4 nT. We conclude that conditions during moderate to large storms can excite unusually low frequency chorus, which is resonant with more energetic electrons than typical chorus, with critical implications for understanding radiation belt evolution. PMID:27667871

  11. RAM-SCB simulations of electron transport and plasma wave scattering during the October 2012 “double-dip” storm

    DOE PAGES

    Jordanova, Vania Koleva; Tu, Weichao; Chen, Yue; Morley, Steven Karl; Panaitescu, Alin -Daniel; Reeves, Geoffrey D.; Kletzing, Craig A.

    2016-09-01

    Here, mechanisms for electron injection, trapping, and loss in the near-Earth space environment are investigated during the October 2012 “double-dip” storm using our magnetically self-consistent ring current model (RAM-SCB). Pitch angle and energy scattering are included for the first time in RAM-SCB using L and magnetic local time (MLT) dependent event-specific chorus wave models inferred from NOAA POES and Van Allen Probes EMFISIS observations. The dynamics of the source (~10s keV) and seed (~100s keV) populations of the radiation belts simulated with RAM-SCB is compared with Van Allen Probes MagEIS observations in the morning sector and with measurements from NOAA-15more » satellite in the predawn and afternoon MLT sectors. We find that although the low-energy (E < 100 keV) electron fluxes are in good agreement with observations, increasing significantly by magnetospheric convection during both SYM-H dips while decreasing during the intermediate recovery phase, the injection of high-energy electrons is underestimated by this mechanism throughout the storm. Local acceleration by chorus waves intensifies the electron fluxes at E ≥ 50 keV considerably and RAM-SCB simulations overestimate the observed trapped fluxes by more than an order of magnitude; the simulated with RAM-SCB precipitating fluxes are weaker and their temporal and spatial evolution agree well with POES/MEPED data.« less

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

    USGS Publications Warehouse

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

    2012-01-01

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

  13. Coarse, intermediate and high resolution numerical simulations of the transition of a tropical wave critical layer to a tropical storm

    NASA Astrophysics Data System (ADS)

    Montgomery, M. T.; Wang, Z.; Dunkerton, T. J.

    2010-11-01

    Recent work has hypothesized that tropical cyclones in the deep Atlantic and eastern Pacific basins develop from within the cyclonic Kelvin cat's eye of a tropical easterly wave critical layer located equatorward of the easterly jet axis. The cyclonic critical layer is thought to be important to tropical cyclogenesis because its cat's eye provides (i) a region of cyclonic vorticity and weak deformation by the resolved flow, (ii) containment of moisture entrained by the developing flow and/or lofted by deep convection therein, (iii) confinement of mesoscale vortex aggregation, (iv) a predominantly convective type of heating profile, and (v) maintenance or enhancement of the parent wave until the developing proto-vortex becomes a self-sustaining entity and emerges from the wave as a tropical depression. This genesis sequence and the overarching framework for describing how such hybrid wave-vortex structures become tropical depressions/storms is likened to the development of a marsupial infant in its mother's pouch, and for this reason has been dubbed the "marsupial paradigm". Here we conduct the first multi-scale test of the marsupial paradigm in an idealized setting by revisiting the Kurihara and Tuleya problem examining the transformation of an easterly wave-like disturbance into a tropical storm vortex using the WRF model. An analysis of the evolving winds, equivalent potential temperature, and relative vertical vorticity is presented from coarse (28 km), intermediate (9 km) and high resolution (3.1 km) simulations. The results are found to support key elements of the marsupial paradigm by demonstrating the existence of a rotationally dominant region with minimal strain/shear deformation near the center of the critical layer pouch that contains strong cyclonic vorticity and high saturation fraction. This localized region within the pouch serves as the "attractor" for an upscale "bottom up" development process while the wave pouch and proto-vortex move together

  14. Intermediate and high resolution numerical simulations of the transition of a tropical wave critical layer to a tropical storm

    NASA Astrophysics Data System (ADS)

    Montgomery, M. T.; Wang, Z.; Dunkerton, T. J.

    2009-12-01

    Recent work has hypothesized that tropical cyclones in the deep Atlantic and eastern Pacific basins develop from the cyclonic Kelvin cat's eye of a tropical easterly wave critical layer located equatorward of the easterly jet axis that typifies the trade wind belt. The cyclonic critical layer is thought to be important to tropical cyclogenesis because its cat's eye provides (i) a region of cyclonic vorticity and weak deformation by the resolved flow, (ii) containment of moisture entrained by the developing flow and/or lofted by deep convection therein, (iii) confinement of mesoscale vortex aggregation, (iv) a predominantly convective type of heating profile, and (v) maintenance or enhancement of the parent wave until the developing proto-vortex becomes a self-sustaining entity and emerges from the wave as a tropical depression. This genesis sequence and the overarching framework for describing how such hybrid wave-vortex structures become tropical depressions/storms is likened to the development of a marsupial infant in its mother's pouch, and for this reason has been dubbed the "marsupial paradigm". Here we conduct the first multi-scale test of the marsupial paradigm in an idealized setting by revisiting the problem of the transformation of an easterly wave-like disturbance into a tropical storm vortex using the WRF model. An analysis of the evolving winds, equivalent potential temperature, and relative vertical vorticity is presented from coarse (28 km) and high resolution (3.1 km) simulations. The results are found to support key elements of the marsupial paradigm by demonstrating the existence of a vorticity dominant region with minimal strain/shear deformation within the critical layer pouch that contains strong cyclonic vorticity and high saturation fraction. This localized region within the pouch serves as the "attractor" for an upscale "bottom up" development process while the wave pouch and proto-vortex move together. Implications of these findings are

  15. Ionospheric disturbances during November 30-December 1, 1988. XI - Abnormal propagations of HF and VHF radio waves

    NASA Astrophysics Data System (ADS)

    Ichinose, Masaru; Kamata, Mitsuhiro

    1992-07-01

    Unusual propagations of HF and VHF radio waves associated with a geomagnetic storm during the period from November 30 to December 1, 1988 are investigated using ionospheric data collected from Japan, China, and Taiwan. The increased field strength of the Japanese frequency standard signals (JJY 2.5 MHz and 5 MHz) which were received at Akita Radio Wave Observatory on the night of November 30 seem to have been caused by increased MUFs and/or scattering due to the disturbed ionosphere. The VHF-TV radio waves propagated from China were received at Kokubunji in Tokyo. One of the most probable mechanisms explaining this unusual propagation of VHF is a one-hop-F2 mode of propagation created by an ionosphere with an anomalously high f0F2. It was found out that these unusual HF and VHF propagations were attributed to unusual ionospheric conditions associated with these geomagnetic disturbances.

  16. Comparing Local-Time and Storm-Phase Distributions of EMIC Waves Observed by Van Allen Probes A, GOES-13, and Halley, Antarctica

    NASA Astrophysics Data System (ADS)

    Ohnsted, M.; Engebretson, M. J.; Posch, J. L.; Lessard, M.; Singer, H. J.; Kletzing, C.; Smith, C. W.; Horne, R. B.

    2015-12-01

    Electromagnetic ion cyclotron (EMIC) waves are expected to be highly efficient in depleting the ring current and in removing outer radiation belt electrons. However, the distribution of these waves in subauroral regions has not been well characterized. In this study we present 0-5 Hz magnetic field data from the Van Allen Probes A (RBSP A) spacecraft (in elliptical equatorial orbit with apogee at 5.8 RE), 0-1 Hz data from GOES-13 (in geosynchronous orbit), and 0-5 Hz data from Halley, Antarctica (L ~4.6), during the first full local-time precession of the Van Allen Probes from October 2012 through July 2014. The considerably different hourly local time vs. L distributions observed point to distinct locations and geomagnetic activity-dependent patterns of EMIC wave activity. GOES-13 wave occurrences exhibited a broad peak in the noon-to-dusk sector. He+ band events peaked near dusk, while H+ band waves peaked near noon, with a secondary peak centered near dawn. More EMIC waves occurred during storm main phase in the He+ band (5%) than in the H+ band (1%), and 80% and 89% of the He+ and H+ band waves, respectively, occurred under late storm recovery or quiet conditions. During all storm phases the local time occurrence patterns of < 0.4 Hz and 0.4-1.0 Hz events at Halley resembled those of He+ and H+ band waves, respectively, at GOES-13. The relatively few wave events at Halley with f > 1.0 Hz occurred at all local times, but with a modest, broad peak near dawn. Roughly 90% of both the 1570 Halley events < 1.0 Hz and the 142 Halley events > 1.0 Hz occurred during late storm recovery and quiet conditions. Events during compressions at GOES-13 (10%), Halley (6%), and RBSP A (6%) peaked near local noon, but with a secondary peak near midnight. Waves observed by RBSP A were distributed rather evenly in local time in all L shell ranges between 3 and 6, and the percentage occurring during late storm recovery or quiet conditions was only 65%. We interpret the difference in

  17. Coarse-clast ridge complexes of the Caribbean: A preliminary basis for distinguishing tsunami and storm-wave origins

    USGS Publications Warehouse

    Morton, R.A.; Richmond, B.M.; Jaffe, B.E.; Gelfenbaum, G.

    2008-01-01

    Coastal gravel-ridge complexes deposited on islands in the Caribbean Sea are recorders of past extreme-wave events that could be associated with either tsunamis or hurricanes. The ridge complexes of Bonaire, Jamaica, Puerto Rico (Isla de Mona), and Guadeloupe consist of polymodal clasts ranging in size from sand to coarse boulders that are derived from the adjacent coral reefs or subjacent rock platforms. Ridge-complex morphologies and crest elevations are largely controlled by availability of sediments, clast sizes, and heights of wave runup. The ridge complexes are internally organized, display textural sorting and a broad range of ages including historical events. Some display seaward-dipping beds and ridge-and-swale topography, and some terminate in fans or steep avalanche slopes. Together, the morphologic, sedimentologic, lithostratigraphic, and chronostratigraphic evidence indicates that shore-parallet ridge complexes composed of gravel and sand that are tens of meters wide and several meters thick are primarily storm-constructed features that have accumulated for a few centuries or millennia as a result of multiple high-frequency intense-wave events. They are not entirely the result of one or a few tsunamis as recently reported. Tsunami deposition may account for some of the lateral ridge-complex accretion or boulder fields and isolated blocks that are associated with the ridge complexes. Copyright ?? 2008, SEPM (Society for Sedimentary Geology).

  18. Ray tracing of gravity waves as a possible warning system for tornadic storms and hurricanes

    NASA Technical Reports Server (NTRS)

    Hung, R. J.; Smith, R. E.

    1978-01-01

    Gravity waves with wave periods of 13 to 15 min and horizontal phase velocities of 90 to 220 m/sec were present in ground-based observations of the upper atmosphere during time periods when tornadoes were occurring and gravity waves with wave periods of 20 to 25 min and horizontal phase velocities of 100 to 200 m/sec were detected when a hurricane was present. Combinations of available neutral atmosphere data and model parameter values were used with a group ray tracing technique in an attempt to locate the sources of these waves. Computed sources of the waves with periods of 13 to 15 min were located within 50 km of the locations where tornadoes touched down from 2 to 4 h later. In the case of the waves with periods of 20 to 25 min it was found that the computed location of the source was roughly where the hurricane would be located 3 h after the waves were excited. The applicability of the present study to a tornado and hurricane warning system is noted.

  19. Thyroid storm

    MedlinePlus

    Thyrotoxic storm; Hyperthyroid storm; Accelerated hyperthyroidism; Thyroid crisis; Thyrotoxicosis - thyroid storm ... Thyroid storm occurs due to a major stress such as trauma, heart attack , or infection. In rare cases, thyroid ...

  20. Can myocardial ischemia be recognized by the exercise electrocardiogram in coronary disease patients with abnormal resting Q waves

    SciTech Connect

    Ahnve, S.; Savvides, M.; Abouantoun, S.; Atwood, J.E.; Froelicher, V.

    1986-05-01

    This study was performed in order to determine whether exercise-induced myocardial ischemia demonstrated by thallium-201 imaging could be detected by ST segment shifts in patients with abnormal Q waves at rest. Fifty-four patients with coronary artery disease and exercise-induced thallium-201 defects were compared to 22 patients with similar Q wave patterns but without thallium-201 exercise defects and to 14 normal subjects. Exercise data were analyzed visually in the 12-lead ECG and for spatial ST vector shifts. Both ST segment depression observed on the 12-lead ECG and spatial criteria were reasonably sensitive and specific for ischemia when the resting ECG showed no Q waves or inferior Q waves (range 69% to 93%). However, when anterior Q waves were present, ST segment shifts could not distinguish patients with ischemia from those with normal perfusion as determined by thallium imaging.

  1. Determination of Effects of Coastal Deformation Caused by Waves and Storms at Black Sea Coast of Turkey utilizing InSAR Technique

    NASA Astrophysics Data System (ADS)

    Seker, D. Z.; Direk, S.; Musaoglu, N.; Gazioglu, C.

    2013-12-01

    Many pressures are exerted on the coastal zones. Winds and waves effect the landscapes mainly on coastal areas. More dramatic deformation occurs with coastal storms like hurricanes which bring strong winds and waves to change the topography of coast. The coastal areas at Black Sea are under pressure of strong wind, waves and storms. Sometimes waves reaches to 10 m height, thus the landscapes of the coastal areas change very dramatically. Advances in Space geodesy have made it possible to determine variations on the Earth with high precision especially by using InSAR technique. InSAR technique is able to cover large areas and can be used in all weather conditions at high spatial resolution. With InSAR technique sub-cm level surface deformation can be determined. Recently, InSAR is the most often used technique to monitor crustal deformation, subsidence and landslides. The aim of this study is to make temporal and spatial analysis and determine the effects of strong wind and wave storms on the coast of Karasu in Black Sea Region of Turkey. By temporal analysis will be able to see the deformation on coast of Karasu in time domain where spatial analysis will show us the changes in landscapes.

  2. Global simulation of EMIC waves in the He+ band for 2001 April 21st storm from RCM-RAM-HOTRAY self-consistent modeling

    NASA Astrophysics Data System (ADS)

    Chen, L.; Thorne, R. M.; Jordanova, V.; Horne, R. B.; Wang, C.

    2009-12-01

    Global distribution of Electromagnetic ion cyclotron (EMIC) wave spectrum in the He+ band is simulated for the 2001 April 21st storm using a self-consistent model, which combines three different codes, the Ring current and atmospheric interaction model (RAM), the Rice Convection Model (RCM), ray tracing code (HOTRAY incorporated with growth rate solver). The ring current H+ provides the source of free energy for EMIC excitation during the storm time, and significant wave gain occurs in the region inside the plume and at the eastward edge of the plume in the dusk sector and pre-midnight sector. The ability of resonating with MeV electrons is also evaluated. Minimum electron resonant energy is generally above 3 MeV. The energetic O+ component of ring current is overestimated in the simulation and thus suppresses significantly on the EMIC waves in the He+. However, the pattern of excitation region basically remains the same.

  3. Decadal variability of extreme wave height representing storm severity in the northeast Atlantic and North Sea since the foundation of the Royal Society

    NASA Astrophysics Data System (ADS)

    Santo, H.; Taylor, P. H.; Gibson, R.

    2016-09-01

    Long-term estimation of extreme wave height remains a key challenge because of the short duration of available wave data, and also because of the possible impact of climate variability on ocean waves. Here, we analyse storm-based statistics to obtain estimates of extreme wave height at locations in the northeast Atlantic and North Sea using the NORA10 wave hindcast (1958-2011), and use a 5 year sliding window to examine temporal variability. The decadal variability is correlated to the North Atlantic oscillation and other atmospheric modes, using a six-term predictor model incorporating the climate indices and their Hilbert transforms. This allows reconstruction of the historic extreme climate back to 1661, using a combination of known and proxy climate indices. Significant decadal variability primarily driven by the North Atlantic oscillation is observed, and this should be considered for the long-term survivability of offshore structures and marine renewable energy devices. The analysis on wave climate reconstruction reveals that the variation of the mean, 99th percentile and extreme wave climates over decadal time scales for locations close to the dominant storm tracks in the open North Atlantic are comparable, whereas the wave climates for the rest of the locations including the North Sea are rather different.

  4. Decadal variability of extreme wave height representing storm severity in the northeast Atlantic and North Sea since the foundation of the Royal Society

    PubMed Central

    Taylor, P. H.; Gibson, R.

    2016-01-01

    Long-term estimation of extreme wave height remains a key challenge because of the short duration of available wave data, and also because of the possible impact of climate variability on ocean waves. Here, we analyse storm-based statistics to obtain estimates of extreme wave height at locations in the northeast Atlantic and North Sea using the NORA10 wave hindcast (1958–2011), and use a 5 year sliding window to examine temporal variability. The decadal variability is correlated to the North Atlantic oscillation and other atmospheric modes, using a six-term predictor model incorporating the climate indices and their Hilbert transforms. This allows reconstruction of the historic extreme climate back to 1661, using a combination of known and proxy climate indices. Significant decadal variability primarily driven by the North Atlantic oscillation is observed, and this should be considered for the long-term survivability of offshore structures and marine renewable energy devices. The analysis on wave climate reconstruction reveals that the variation of the mean, 99th percentile and extreme wave climates over decadal time scales for locations close to the dominant storm tracks in the open North Atlantic are comparable, whereas the wave climates for the rest of the locations including the North Sea are rather different. PMID:27713662

  5. Assessment and comparison of extreme sea levels and waves during the 2013/14 storm season in two UK coastal regions

    NASA Astrophysics Data System (ADS)

    Wadey, M. P.; Brown, J. M.; Haigh, I. D.; Dolphin, T.; Wisse, P.

    2015-10-01

    The extreme sea levels and waves experienced around the UK's coast during the 2013/14 winter caused extensive coastal flooding and damage. Coastal managers seek to place such extremes in relation to the anticipated standards of flood protection, and the long-term recovery of the natural system. In this context, return periods are often used as a form of guidance. This paper provides these levels for the winter storms, and discusses their application to the given data sets for two UK case study sites: Sefton, northwest England, and Suffolk, east England. Tide gauge records and wave buoy data were used to compare the 2013/14 storms with return periods from a national data set, and also joint probabilities of sea level and wave heights were generated, incorporating the recent events. The 2013/14 high waters and waves were extreme due to the number of events, as well as the extremity of the 5 December 2013 "Xaver" storm, which had a high return period at both case study sites. The national-scale impact of this event was due to its coincidence with spring high tide at multiple locations. Given that this event is such an outlier in the joint probability analyses of these observed data sets, and that the season saw several events in close succession, coastal defences appear to have provided a good level of protection. This type of assessment could in the future be recorded alongside defence performance and upgrade. Ideally other variables (e.g. river levels at estuarine locations) would also be included, and with appropriate offsetting for local trends (e.g. mean sea-level rise) so that the storm-driven component of coastal flood events can be determined. This could allow long-term comparison of storm severity, and an assessment of how sea-level rise influences return levels over time, which is important for consideration of coastal resilience in strategic management plans.

  6. Impact of Current-Wave Interaction on Storm Surge Simulation: A Case Study for Hurricane Bob

    NASA Astrophysics Data System (ADS)

    Sun, Y.; Chen, C.; Beardsley, R. C.; Xu, Q.; Qi, J.; Lin, H.

    2012-12-01

    Hurricane Bob moved up the US east coast and crossed over southern New England and the Gulf of Maine (with peak marine winds up to 100 mph) on 19-20 August 1991, causing significant damage along the coast and shelf. A three-dimensional fully wave-current coupled Finite-Volume Community Ocean Model (FVCOM) system was developed and applied to simulate and examine the coastal ocean responses to Hurricane Bob, Results from process study-oriented experiments show that wave-current interaction caused a significant change of the current direction and mixing, but had relatively little contribution to the maximum sea level along the coast. Diagnostic analyses suggest that the contribution of hurricane-derived wave-current interaction to the net water flux varies in space and time. While sea level change along the coast was mainly driven by the barotropic water flux and the vertically integrated water transports were essentially the same for cases with and without water stratification, the hurricane-induced wave-current interaction could generate strong vertical current shear in the stratified areas, leading to strong offshore transport near the bottom and enhanced water mixing over the continental shelf. Stratification also could result in a significant difference of water currents around islands where the water is not vertically well mixed.

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

    NASA Astrophysics Data System (ADS)

    Bastidas, Luis A.; Knighton, James; Kline, Shaun W.

    2016-09-01

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

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

    NASA Astrophysics Data System (ADS)

    Bastidas, L. A.; Knighton, J.; Kline, S. W.

    2015-10-01

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

  9. Storm fronts over galaxy discs: models of how waves generate extraplanar gas and its anomalous kinematics

    NASA Astrophysics Data System (ADS)

    Struck, Curtis; Smith, Daniel C.

    2009-09-01

    The existence of partially ionized, diffuse gas and dust clouds at kiloparsec scale distances above the central planes of edge-on, galaxy discs was an unexpected discovery about 20 years ago. Subsequent observations showed that this extended or extraplanar diffuse interstellar gas (EDIG) has rotation velocities approximately 10-20 per cent lower than those in the central plane, and has been hard to account for. Here, we present results of hydrodynamic models, with radiative cooling and heating from star formation. We find that in models with star formation generated stochastically across the disc, an extraplanar gas layer is generated as long as the star formation is sufficiently strong. However, this gas rotates at nearly the same speed as the midplane gas. We then studied a range of models with imposed spiral or bar waves in the disc. EDIG layers were also generated in these models, but primarily over the wave regions, not over the entire disc. Because of this partial coverage, the EDIG clouds move radially, as well as vertically, with the result that observed kinematic anomalies are reproduced. The implication is that the kinematic anomalies are the result of three-dimensional motions when the cylindrical symmetry of the disc is broken. Thus, the kinematic anomalies are the result of bars or strong waves, and more face-on galaxies with such waves should have an asymmetric EDIG component. The models also indicate that the EDIG can contain a significant fraction of cool gas, and that some star formation can be triggered at considerable heights above the disc mid-plane. We expect all of these effects to be more prominent in young, forming discs, to play a role in rapidly smoothing disc asymmetries and in working to self-regulate disc structure.

  10. Acoustic and gravity waves in the neutral atmosphere and the ionosphere, generated by severe storms

    NASA Technical Reports Server (NTRS)

    Balachandran, N. K.

    1983-01-01

    Gravity waves in the neutral atmosphere and their propagation in the ionosphere and the study of infrasonic signals from thunder were investigated. Doppler shifts of the order of 0.1 Hz are determined and they provide high-resolution measurements of the movements in the ionosphere. By using an array of transmitters with different frequencies and at different locations, the horizontal and vertical propagation vectors of disturbances propagating through the ionosphere are determined.

  11. Impact of current-wave interaction on storm surge simulation: A case study for Hurricane Bob

    NASA Astrophysics Data System (ADS)

    Sun, Yunfang; Chen, Changsheng; Beardsley, Robert C.; Xu, Qichun; Qi, Jianhua; Lin, Huichan

    2013-05-01

    Hurricane Bob moved up the U.S. east coast and crossed over southern New England and the Gulf of Maine [with peak marine winds up to 54 m/s (100 mph)] on 19-20 August 1991, causing significant damage along the coast and shelf. A 3-D fully wave-current-coupled finite-volume community ocean model system was developed and applied to simulate and examine the coastal ocean responses to Hurricane Bob. Results from process study-oriented experiments showed that the impact of wave-current interaction on surge elevation varied in space and time, more significant over the shelf than inside the inner bays. While sea level change along the coast was mainly driven by the water flux controlled by barotropic dynamics and the vertically integrated highest water transports were essentially the same for cases with and without water stratification, the hurricane-induced wave-current interaction could generate strong vertical current shear in the stratified areas, leading to a strong offshore transport near the bottom and vertical turbulent mixing over the continental shelf. Stratification could also result in a significant difference of water currents around islands where the water is not vertically well mixed.

  12. Assessment and comparison of extreme sea levels and waves during the 2013/2014 storm season in two UK coastal regions

    NASA Astrophysics Data System (ADS)

    Wadey, M. P.; Brown, J. M.; Haigh, I. D.; Dolphin, T.; Wisse, P.

    2015-04-01

    The extreme sea levels and waves experienced around the UK's coast during the 2013/2014 winter caused extensive coastal flooding and damage. In such circumstances, coastal managers seek to place such extremes in relation to the anticipated standards of flood protection, and the long-term recovery of the natural system. In this context, return periods are often used as a form of guidance. We therefore provide these levels for the winter storms, as well as discussing their application to the given data sets and case studies (two UK case study sites: Sefton, northwest England; and Suffolk, east England). We use tide gauge records and wave buoy data to compare the 2013/2014 storms with return periods from a national dataset, and also generate joint probabilities of sea level and waves, incorporating the recent events. The UK was hit at a national scale by the 2013/2014 storms, although the return periods differ with location. We also note that the 2013/2014 high water and waves were extreme due to the number of events, as well as the extremity of the 5 December 2013 "Xaver" storm, which had a very high return period at both case study sites. Our return period analysis shows that the national scale impact of this event is due to its coincidence with spring high tide at multiple locations as the tide and storm propagated across the continental shelf. Given that this event is such an outlier in the joint probability analyses of these observed data sets, and that the season saw several events in close succession, coastal defences appear to have provided a good level of protection. This type of assessment should be recorded alongside details of defence performance and upgrade, with other variables (e.g. river levels at estuarine locations) included and appropriate offsetting for linear trends (e.g. mean sea level rise) so that the storm-driven component of coastal flood events can be determined. Local offsetting of the mean trends in sea level allows long-term comparison of

  13. The Nonlinear Coupling of Electromagnetic Ion Cyclotron and Lower Hybrid Waves in the Ring Current Region: The Magnetic Storm May 1-7 1998

    NASA Technical Reports Server (NTRS)

    Khazanov, G. V.; Krivorutsky, E.; Gamayunov, K.; Avanov, L.

    2003-01-01

    The excitation of lower hybrid waves (LHWs) is a widely discussed mechanism of interaction between plasma species in space, and is one of the unresolved questions of magnetospheric multi-ion plasmas. In this paper we present the morphology, dynamics, and level of LHW activity generated by electromagnetic ion cyclotron (EMIC) waves during the May 2-7, 1998 storm period on the global scale. The LHWs were calculated based on our newly developed self-consistent model that couples the system of two kinetic equations: one equation describes the ring current (RC) ion dynamic, and another equation describes the evolution of EMIC waves. It is found that the LHWs are excited by helium ions due to their mass dependent drift in the electric field of EMIC waves. The level of LHW activity is calculated assuming that the induced scattering process is the main saturation mechanism for these waves. The calculated LHWs electric fields are consistent with the observational data.

  14. Storm-runoff generation in the Permanente Creek drainage basin, west central California - An example of flood-wave effects on runoff composition

    USGS Publications Warehouse

    Nolan, K.M.; Hill, B.R.

    1990-01-01

    Variations in the isotopic and chemical composition of storm runoff in the 10.6-km2 Permanente Creek basin, Santa Clara County, California, indicate that changes in water composition lag behind changes in streamflow. This lag occurs even though field observations and rainfall-runoff modeling indicate that much of the storm runoff must be composed of "new" water running off impervious surfaces. The apparent incompatibility posed by the presence of "old" water and the direct and indirect evidence that surface runoff contributes substantially to storm runoff can be explained if initial rises in streamflow result from effects of flood waves. Flood waves composed of old channel water reach downstream locations ahead of the new water derived from impervious areas. By this mechanism, streamflow can rise rapidly in response to surface runoff and still be composed of large amounts of old water. Data collected in Permanente Creek indicate that flood waves can occur even in small basins, at least when those basins contain impervious surfaces. ?? 1990.

  15. Green roof and storm water management policies: monitoring experiments on the ENPC Blue Green Wave

    NASA Astrophysics Data System (ADS)

    Versini, Pierre-Antoine; Gires, Auguste; Fitton, George; Tchiguirinskaia, Ioulia; Schertzer, Daniel

    2015-04-01

    Currently widespread in new urban projects, green roofs have shown a positive impact on urban runoff at the building/parcel scale. Nevertheless, there is no specific policy promoting their implementation neither in Europe nor in France. Moreover they are not taken into account (and usually considered as an impervious area) in the sizing of a retention basin for instance. An interesting example is located in the heart of the Paris-East Cluster for Science and Technology (Champs-sur-Marne, France). Since 2013 a large (1 ha) wavy-form vegetated roof (called bleu green wave) is implemented. Green roof area and impervious areas are connected to a large retention basin, which has been oversized. The blue green wave represents a pioneering site where an initially amenity (decorative) design project has been transformed into a research oriented one. Several measurement campaigns have been conducted to investigate and better understand the hydrological behaviour of such a structure. Rainfall, humidity, wind velocity, water content and temperature have been particularly studied. The data collected are used for several purposes: (i) characterize the spatio-temporal variability of the green roof response, (ii) calibrate and validate a specific model simulating its hydrological behavior. Based on monitoring and modeling results, green roof performances will be quantified. It will be possible to estimate how they can reduce stormwater runoff and how these performances can vary in space and in time depending on green roof configuration, rainfall event characteristics and antecedent conditions. These quantified impacts will be related to regulation rules established by stormwater managers in order to connect the parcel to the sewer network. In the particular case of the building of a retention basin, the integration of green roof in the sizing of the basin will be studied. This work is funded by the European Blue Green Dream project (http://bgd.org.uk/, funded by Climate

  16. A case study of combined wave and water levels under storm conditions using WAM and SWAN in a shallow water application

    NASA Astrophysics Data System (ADS)

    Brown, Jennifer M.

    Extreme storm events in Liverpool Bay, UK, are under investigation. A recent storm, 18th January 2007, has been used to investigate different modelling approaches to accurately simulate wave-surge conditions in shallow water. In Liverpool Bay wave and surge influence and their interaction are often considered in many studies. The tide-surge-wave interaction has been modelled in the Irish Sea using the Proudman Oceanographic Laboratory Coastal Ocean Modelling System (POLCOMS) coupled to the state-of-the-art 3rd generation spectral WAve Model (WAM). Waves are locally generated in Liverpool Bay, while the surge is locally and externally generated. To include the external surge the 1.8 km Irish Sea model has been nested, using a 1-way approach, into the 1/9° by 1/6° operational Continental Shelf surge model. To investigate the performance of POLCOMS-WAM in shallow water a 180 m Liverpool Bay model has been nested within the Irish Sea model. For this high resolution model the state-of-the-art 3rd generation Simulating WAves Nearshore (SWAN) spectral model is used to further develop WAM, modified for shallow water. A POLCOMS-WAM and POLCOMS-SWAN (1-way) coupled model has been implemented to assess the effects of tide-surge-wave interaction at the coast. Investigation of the significant wave height and surge elevation reveals that when modified for shallow water WAM performs as well as SWAN. Two-way coupling between POLCOMS-WAM allows wave-setup to be included in the surge prediction greatly improving the hydrodynamic result. A drawback to using WAM is the computational expense, making SWAN more suitable for simulations exceeding a few days in duration.

  17. Field observation of morpho-dynamic processes during storms at a Pacific beach, Japan: role of long-period waves in storm-induced berm erosion.

    PubMed

    Mizuguchi, Masaru; Seki, Katsumi

    2015-01-01

    Many ultrasonic wave gages were placed with a small spacing across the swash zone to monitor either sand level or water level. Continuous monitoring conducted for a few years enabled the collection of data on the change in wave properties as well as swash-zone profiles. Data sets including two cases of large-scale berm erosion were analyzed. The results showed that 1) shoreline erosion started when high waves with significant power in long-period (1 to 2 min.) waves reached the top of a well-developed berm with the help of rising tide; 2) the beach in the swash zone was eroded with higher elevation being more depressed, while the bottom elevation just outside the swash zone remained almost unchanged; and 3) erosion stopped in a few hours after the berm was completely eroded or the swash-zone slope became uniformly mild. These findings strongly suggest that long waves play a dominant role in the swash-zone dynamics associated with these erosional events.

  18. Defining Coastal Storm and Quantifying Storms Applying Coastal Storm Impulse Parameter

    NASA Astrophysics Data System (ADS)

    Mahmoudpour, Nader

    2014-05-01

    What defines a storm condition and what would initiate a "storm" has not been uniquely defined among scientists and engineers. Parameters that have been used to define a storm condition can be mentioned as wind speed, beach erosion and storm hydrodynamics parameters such as wave height and water levels. Some of the parameters are storm consequential such as beach erosion and some are not directly related to the storm hydrodynamics such as wind speed. For the purpose of the presentation, the different storm conditions based on wave height, water levels, wind speed and beach erosion will be discussed and assessed. However, it sounds more scientifically to have the storm definition based on the hydrodynamic parameters such as wave height, water level and storm duration. Once the storm condition is defined and storm has initiated, the severity of the storm would be a question to forecast and evaluate the hazard and analyze the risk in order to determine the appropriate responses. The correlation of storm damages to the meteorological and hydrodynamics parameters can be defined as a storm scale, storm index or storm parameter and it is needed to simplify the complexity of variation involved developing the scale for risk analysis and response management. A newly introduced Coastal Storm Impulse (COSI) parameter quantifies storms into one number for a specific location and storm event. The COSI parameter is based on the conservation of linear, horizontal momentum to combine storm surge, wave dynamics, and currents over the storm duration. The COSI parameter applies the principle of conservation of momentum to physically combine the hydrodynamic variables per unit width of shoreline. This total momentum is then integrated over the duration of the storm to determine the storm's impulse to the coast. The COSI parameter employs the mean, time-averaged nonlinear (Fourier) wave momentum flux, over the wave period added to the horizontal storm surge momentum above the Mean High

  19. Observations of storm morphodynamics using Coastal Lidar and Radar Imaging System (CLARIS): Importance of wave refraction and dissipation over complex surf-zone morphology at a shoreline erosional hotspot

    NASA Astrophysics Data System (ADS)

    Brodie, Katherine L.

    Elevated water levels and large waves during storms cause beach erosion, overwash, and coastal flooding, particularly along barrier island coastlines. While predictions of storm tracks have greatly improved over the last decade, predictions of maximum water levels and variations in the extent of damage along a coastline need improvement. In particular, physics based models still cannot explain why some regions along a relatively straight coastline may experience significant erosion and overwash during a storm, while nearby locations remain seemingly unchanged. Correct predictions of both the timing of erosion and variations in the magnitude of erosion along the coast will be useful to both emergency managers and homeowners preparing for an approaching storm. Unfortunately, research on the impact of a storm to the beach has mainly been derived from "pre" and "post" storm surveys of beach topography and nearshore bathymetry during calm conditions. This has created a lack of data during storms from which to ground-truth model predictions and test hypotheses that explain variations in erosion along a coastline. We have developed Coastal Lidar and Radar Imaging System (CLARIS), a mobile system that combines a terrestrial scanning laser and an X-band marine radar system using precise motion and location information. CLARIS can operate during storms, measuring beach topography, nearshore bathymetry (from radar-derived wave speed measurements), surf-zone wave parameters, and maximum water levels remotely. In this dissertation, we present details on the development, design, and testing of CLARIS and then use CLARIS to observe a 10 km section of coastline in Kitty Hawk and Kill Devil Hills on the Outer Banks of North Carolina every 12 hours during a Nor'Easter (peak wave height in 8 m of water depth = 3.4 m). High decadal rates of shoreline change as well as heightened erosion during storms have previously been documented to occur within the field site. In addition, complex

  20. Dust Storm

    Atmospheric Science Data Center

    2013-04-16

    article title:  Massive Dust Storm over Australia     View ... at JPL September 22, 2009 - Massive dust storm over Australia. project:  MISR category:  ... Sep 22, 2009 Images:  Dust Storm location:  Australia and New Zealand ...

  1. Equatorial sporadic E-layer abnormal density enhancement during the recovery phase of the December 2006 magnetic storm: A case study

    NASA Astrophysics Data System (ADS)

    Resende, L. C. A.; Denardini, C. M.

    2012-04-01

    Sporadic layers appear in the equatorial region ( E sq) between 90 and 130 km mainly due to irregularities in the electrojet equatorial (EEJ) current. In the present work, we have analyzed the behavior of the frequency parameters associated with these sporadic layers, covering the days before, during, and subsequent to, the intense magnetic storm that occurred on December 14, 2006. The parameters used in our analyses are the top frequency ( f t E s) and blanketing frequency ( f b E s) of the E s layer as measured over São Luís, Brazil (2.33°S, 44.2°W, dip: -4.5°) by digital ionosonde. A tentative association between these parameters and X-ray data measured by sensors on board the GOES satellite was carried out. Also, we investigated the effects on the dynamics of the equatorial electrojet using magnetometer data related to the presence of these E s layers. Our analyses show that there are notable changes in the f b E s, which are characterized by the occurrence of peaks that exceed the ambient background values.

  2. Distribution of stable isotopes in arid storms . II. A double-component model of kinematic wave flow and transport

    NASA Astrophysics Data System (ADS)

    Yakirevich, Alexander; Dody, Avraham; Adar, Eilon M.; Borisov, Viacheslav; Geyh, Mebus

    A new mathematical method based on a double-component model of kinematic wave flow and approach assesses the dynamic isotopic distribution in arid rain storms and runoff. This model describes the transport and δ18O evolution of rainfall to overland flow and runoff in an arid rocky watershed with uniformly distributed shallow depression storage. The problem was solved numerically. The model was calibrated using a set of temporal discharge and δ18O distribution data for rainfall and runoff collected on a small rocky watershed at the Sede Boker Experimental Site, Israel. Simulation of a reliable result with respect to observation was obtained after parameter adjustment by trial and error. Sensitivity analysis and model application were performed. The model is sensitive to changes in parameters characterizing the depression storage zones. The model reflects the effect of the isotopic memory in the water within the depression storage between sequential rain spells. The use of the double-component model of kinematic wave flow and transport provides an appropriate qualitative and quantitative fitting between computed and observed δ18O distribution in runoff. RésuméUne nouvelle méthode mathématique basée sur un modèle à double composante d'écoulement et de transport par une onde cinématique a été développée pour évaluer la distribution dynamique en isotopes dans les précipitations et dans l'écoulement en région aride. Ce modèle décrit le transport et les variations des δ18O de la pluie vers le ruissellement et l'écoulement de surface dans un bassin aride rocheux où le stockage se fait dans des dépressions peu profondes uniformément réparties. Le problème a été résolu numériquement. Le modèle a été calibré au moyen d'une chronique de débits et d'une distribution des δ18O dans la pluie et dans l'écoulement de surface sur un petit bassin versant rocheux du site expérimental de Sede Boker (Israël). La simulation d'un résultat cr

  3. Storm impact for barrier islands

    USGS Publications Warehouse

    Sallenger,, Asbury H., Jr.

    2000-01-01

    A new scale is proposed that categorizes impacts to natural barrier islands resulting from tropical and extra-tropical storms. The proposed scale is fundamentally different than existing storm-related scales in that the coupling between forcing processes and the geometry of the coast is explicitly included. Four regimes, representing different levels of impact, are defined. Within each regime, patterns and relative magnitudes of net erosion and accretion are argued to be unique. The borders between regimes represent thresholds defining where processes and magnitudes of impacts change dramatically. Impact level 1 is the 'swash' regime describing a storm where runup is confined to the foreshore. The foreshore typically erodes during the storm and recovers following the storm; hence, there is no net change. Impact level 2 is the 'collision' regime describing a storm where the wave runup exceeds the threshold of the base of the foredune ridge. Swash impacts the dune forcing net erosion. Impact level 3 is the 'overwash' regime describing a storm where wave runup overtops the berm or, if present, the foredune ridge. The associated net landward sand transport contributes to net migration of the barrier landward. Impact level 4 is the 'inundation' regime describing a storm where the storm surge is sufficient to completely and continuously submerge the barrier island. Sand undergoes net landward transport over the barrier island; limited evidence suggests the quantities and distance of transport are much greater than what occurs during the 'overwash' regime.

  4. Multi-decadal shoreline changes on Takú Atoll, Papua New Guinea: Observational evidence of early reef island recovery after the impact of storm waves

    NASA Astrophysics Data System (ADS)

    Mann, Thomas; Westphal, Hildegard

    2016-03-01

    Hurricanes, tropical cyclones and other high-magnitude events are important steering mechanisms in the geomorphic development of coral reef islands. Sandy reef islands located outside the storm belts are strongly sensitive to the impact of occasional high-magnitude events and show abrupt, commonly erosive geomorphic change in response to such events. Based on the interpretation of remote sensing data, it is well known that the process of landform recovery might take several decades or even longer. However, despite the increasing amount of scientific attention towards short- and long-term island dynamics, the lack of data and models often prevent a robust analysis of the timing and nature of recovery initiation. Here we show how natural island recovery starts immediately after the impact of a high-magnitude event. We analyze multi-temporal shoreline changes on Takú Atoll, Papua New Guinea and combine our findings with a unique set of published field observations (Smithers and Hoeke, 2014). Trends of shoreline change since 1943 and changes in planform island area indicate a long-term accretionary mode for most islands. Apparent shoreline instability is detected for the last decade of analysis, however this can be explained by the impact of storm waves in December 2008 that (temporarily?) masked the long-term trend. The transition from negative to positive rates of change in the aftermath of this storm event is indicative of inherent negative feedback processes that counteract short-term changes in energy input and represent the initiation of island recovery. Collectively, our results support the concept of dynamic rather than static reef islands and clearly demonstrate how short-term processes can influence interpretations of medium-term change.

  5. Dust Storm

    Atmospheric Science Data Center

    2013-04-16

    ... April 11, 2004 (top panels) contrast strongly with the dust storm that swept across Iraq and Saudi Arabia on May 13, 2004 (bottom panels). ... Apr 11 and May 13, 2004 Images:  Dust Storm location:  Middle East thumbnail:  ...

  6. Thyroid storm: an updated review.

    PubMed

    Chiha, Maguy; Samarasinghe, Shanika; Kabaker, Adam S

    2015-03-01

    Thyroid storm, an endocrine emergency first described in 1926, remains a diagnostic and therapeutic challenge. No laboratory abnormalities are specific to thyroid storm, and the available scoring system is based on the clinical criteria. The exact mechanisms underlying the development of thyroid storm from uncomplicated hyperthyroidism are not well understood. A heightened response to thyroid hormone is often incriminated along with increased or abrupt availability of free hormones. Patients exhibit exaggerated signs and symptoms of hyperthyroidism and varying degrees of organ decompensation. Treatment should be initiated promptly targeting all steps of thyroid hormone formation, release, and action. Patients who fail medical therapy should be treated with therapeutic plasma exchange or thyroidectomy. The mortality of thyroid storm is currently reported at 10%. Patients who have survived thyroid storm should receive definite therapy for their underlying hyperthyroidism to avoid any recurrence of this potentially fatal condition.

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

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

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

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

    NASA Astrophysics Data System (ADS)

    Cannaby, H.; Palmer, M. D.; Howard, T.; Bricheno, L.; Calvert, D.; Krijnen, J.; Wood, R.; Tinker, J.; Bunney, C.; Harle, J.; Saulter, A.; O'Neill, C.; Bellingham, C.; Lowe, J.

    2015-12-01

    Singapore is an island state with considerable population, industries, commerce and transport located in coastal areas at elevations less than 2 m making it vulnerable to sea-level rise. Mitigation against future inundation events requires a quantitative assessment of risk. To address this need, regional projections of changes in (i) long-term mean sea level and (ii) the frequency of extreme storm surge and wave events have been combined to explore potential changes to coastal flood risk over the 21st century. Local changes in time mean sea level were evaluated using the process-based climate model data and methods presented in the IPCC AR5. Regional surge and wave solutions extending from 1980 to 2100 were generated using ~ 12 km resolution surge (Nucleus for European Modelling of the Ocean - NEMO) and wave (WaveWatchIII) models. Ocean simulations were forced by output from a selection of four downscaled (~ 12 km resolution) atmospheric models, forced at the lateral boundaries by global climate model simulations generated for the IPCC AR5. Long-term trends in skew surge and significant wave height were then assessed using a generalised extreme value model, fit to the largest modelled events each year. An additional atmospheric solution downscaled from the ERA-Interim global reanalysis was used to force historical ocean model simulations extending from 1980-2010, enabling a quantitative assessment of model skill. Simulated historical sea surface height and significant wave height time series were compared to tide gauge data and satellite altimetry data respectively. Central estimates of the long-term mean sea level rise at Singapore by 2100 were projected to be 0.52 m (0.74 m) under the RCP 4.5 (8.5) scenarios respectively. Trends in surge and significant wave height 2 year return levels were found to be statistically insignificant and/or physically very small under the more severe RCP8.5 scenario. We conclude that changes to long-term mean sea level constitute the

  9. Magnetic Storms

    NASA Technical Reports Server (NTRS)

    Tsurutani, Bruce T.; Gonzalez, Walter D.

    1998-01-01

    One of the oldest mysteries in geomagnetism is the linkage between solar and geomagnetic activity. The 11-year cycles of both the numbers of sunspots and Earth geomagnetic storms were first noted by Sabine. A few years later, speculation on a causal relationship between flares and storms arose when Carrington reported that a large magnetic storm followed the great September 1859 solar flare. However, it was not until this century that a well-accepted statistical survey on large solar flares and geomagnetic storms was performed, and a significant correlation between flares and geomagnetic storms was noted. Although the two phenomena, one on the Sun and the other on the Earth, were statistically correlated, the exact physical linkage was still an unknown at this time. Various hypotheses were proposed, but it was not until interplanetary spacecraft measurements were available that a high-speed plasma stream rich in helium was associated with an intense solar flare. The velocity of the solar wind increased just prior to and during the helium passage, identifying the solar ejecta for the first time. Space plasma measurements and Skylab's coronagraph images of coronal mass elections (CMES) from the Sun firmly established the plasma link between the Sun and the Earth. One phenomenon associated with magnetic storms is brilliant "blood" red auroras, as shown.

  10. Geomorphological impacts of high-latitude storm waves on low-latitude reef islands - Observations of the December 2008 event on Nukutoa, Takuu, Papua New Guinea

    NASA Astrophysics Data System (ADS)

    Smithers, S. G.; Hoeke, R. K.

    2014-10-01

    Low-latitude reefs and reef islands usually experience relatively benign climatic and hydrodynamic conditions due to their location near to the equator, outside of the major storm belts, and they typically exhibit geomorphological traits that reflect the prevailing low-energy conditions. For example, algal ridges are poorly developed, reef flat boulder zones are modest or lacking, rubble banks are rare, and reef islands tend to be low and dominated by sand. Nukutoa is a low-lying triangular-shaped reef island of ~ 6 ha located on the eastern rim of Takuu atoll (4°45‧S, 157°2‧E), Papua New Guinea, approximately 300 km northeast of Bougainville. The approximately 450 residents of Takuu all live on Nukutoa. In December 2008 Takuu was struck by several days of very high water levels and waves, which washed completely over approximately 50% of Nukutoa. GPS shoreline mapping and topographic surveys of the island were undertaken in the days immediately prior to the event, and were repeated immediately after. Homes and village infrastructure were damaged during this event, which eroded around 60% of the shoreline, and deposited a sand sheet averaging around 50 mm thick over approximately 13% of the island. This event was generated by two distant storms - one located > 6000 km away near 50°N, and affected a wide area of the Western Pacific. Oral histories record at least five similar events since the 1940s. In this paper we document the geomorphic impacts of the December 2008 event and discuss the possible significance of similar events in the past, and in the future.

  11. Single-subject-based whole-brain MEG slow-wave imaging approach for detecting abnormality in patients with mild traumatic brain injury.

    PubMed

    Huang, Ming-Xiong; Nichols, Sharon; Baker, Dewleen G; Robb, Ashley; Angeles, Annemarie; Yurgil, Kate A; Drake, Angela; Levy, Michael; Song, Tao; McLay, Robert; Theilmann, Rebecca J; Diwakar, Mithun; Risbrough, Victoria B; Ji, Zhengwei; Huang, Charles W; Chang, Douglas G; Harrington, Deborah L; Muzzatti, Laura; Canive, Jose M; Christopher Edgar, J; Chen, Yu-Han; Lee, Roland R

    2014-01-01

    Traumatic brain injury (TBI) is a leading cause of sustained impairment in military and civilian populations. However, mild TBI (mTBI) can be difficult to detect using conventional MRI or CT. Injured brain tissues in mTBI patients generate abnormal slow-waves (1-4 Hz) that can be measured and localized by resting-state magnetoencephalography (MEG). In this study, we develop a voxel-based whole-brain MEG slow-wave imaging approach for detecting abnormality in patients with mTBI on a single-subject basis. A normative database of resting-state MEG source magnitude images (1-4 Hz) from 79 healthy control subjects was established for all brain voxels. The high-resolution MEG source magnitude images were obtained by our recent Fast-VESTAL method. In 84 mTBI patients with persistent post-concussive symptoms (36 from blasts, and 48 from non-blast causes), our method detected abnormalities at the positive detection rates of 84.5%, 86.1%, and 83.3% for the combined (blast-induced plus with non-blast causes), blast, and non-blast mTBI groups, respectively. We found that prefrontal, posterior parietal, inferior temporal, hippocampus, and cerebella areas were particularly vulnerable to head trauma. The result also showed that MEG slow-wave generation in prefrontal areas positively correlated with personality change, trouble concentrating, affective lability, and depression symptoms. Discussion is provided regarding the neuronal mechanisms of MEG slow-wave generation due to deafferentation caused by axonal injury and/or blockages/limitations of cholinergic transmission in TBI. This study provides an effective way for using MEG slow-wave source imaging to localize affected areas and supports MEG as a tool for assisting the diagnosis of mTBI. PMID:25009772

  12. The perfect storm: Unusual synchronisation of the components of wave energy spectra dominates episodic soft-cliff erosion.

    NASA Astrophysics Data System (ADS)

    Hackney, Christopher; Darby, Stephen

    2015-04-01

    Between December 2013 and February 2014 the United Kingdom experienced the stormiest winter on record. The persistent low pressure systems arriving from the North Atlantic during this period resulted in some of the most energetic maritime conditions ever recorded along the English Channel. The unprotected soft cliffs which comprise the south west Isle of Wight coastline were highly exposed to these conditions, facing the full force of extreme sea-levels and significant wave heights. Although long term rates of soft-cliff erosion have previously been defined for this coastline, the role of such extreme forcings on rates of soft-cliff erosion has not previously been document, and is therefore relatively poorly understood. We employed pre-event LIDAR and post-event RTK-GPS shoreline surveys in tandem with hourly sea-levels and significant wave height records from the English Channel to build an unprecedented data set that we use here to determine the response of this soft-cliff coastline to the extreme forcings of the 2013/2014 winter. It was found that the between October 2013 and March 2014, the south west Isle of Wight eroded, on average 4.25 m (σ = 3.6m). Such a high degree of erosion is approximately a factor of nine times greater than the long term average retreat rate of ~0.5 m/yr for this coastline and is the largest recorded erosion event since the start of reliable records began. The extreme erosion observed is shown to be a result of the synchronisation between sea-levels and wave heights. Indeed, we show that a 7-hour lag of the wave height record relative to background sea-level would have resulted in only half (2.1 m) of the observed erosion. An analysis of the historical record implies that previous extreme erosion events were a function of similar synchronisation between sea-levels and wave heights, thus it is likely that future changes in the timing of peak sea-levels and wave heights have the potential to outweigh changes in magnitude in terms of

  13. Relations between depressive symptoms, anxiety, and T Wave abnormalities in subjects without clinically-apparent cardiovascular disease (from the Multi-Ethnic Study of Atherosclerosis [MESA]).

    PubMed

    Whang, William; Peacock, James; Soliman, Elsayed Z; Alcantara, Carmela; Nazarian, Saman; Shah, Amit J; Davidson, Karina W; Shea, Steven; Muntner, Paul; Shimbo, Daichi

    2014-12-15

    The aim of this study was to test the hypothesis that depression and anxiety are associated with electrocardiographic (ECG) repolarization abnormalities in the Multi-Ethnic Study of Atherosclerosis (MESA), a cohort free of symptomatic cardiovascular disease. Depressive symptoms were assessed by using the Center for Epidemiologic Studies Depression Scale and trait anxiety symptoms by using the Spielberger State-Trait Anxiety Inventory; both were categorized according to uppermost quartile. T-wave inversions in ECG leads other than V1 to V3 were obtained from electrocardiograms obtained at rest during the baseline examination. Participants with major intraventricular conduction abnormalities and those taking antiarrhythmics, antidepressants, and/or antipsychotics were excluded. Logistic regression models were estimated with multivariable adjustment for traditional cardiovascular disease risk factors. Among 5,906 participants, elevated depressive symptoms were associated with increased odds of T-wave inversion after multivariable adjustment (odds ratio 2.02, 95% confidence interval 1.33 to 3.06, p = 0.001), whereas greater trait anxiety was associated with reduced odds of T-wave inversion (odds ratio 0.47, 95% confidence interval 0.29 to 0.77, p = 0.003). The divergent associations of depressive symptoms and trait anxiety with ECG T-wave inversions were similar in men and women, and these associations were present across the racial and ethnic subgroups (non-Hispanic white, African-American, Hispanic, and Chinese). In conclusion, symptoms of depression and anxiety were independently yet oppositely associated with ECG T-wave inversions. Negative emotions may have a differential impact on cardiovascular mortality through unique relations with cardiac repolarization.

  14. Severe storm electricity

    NASA Technical Reports Server (NTRS)

    Rust, W. D.; Macgorman, D. R.

    1985-01-01

    During FY-85, Researchers conducted a field program and analyzed data. The field program incorporated coordinated measurements made with a NASA U2. Results include the following: (1) ground truth measurements of lightning for comparison with those obtained by the U2; (2) analysis of dual-Doppler radar and dual-VHF lightning mapping data from a supercell storm; (3) analysis of synoptic conditions during three simultaneous storm systems on 13 May 1983 when unusually large numbers of positive cloud-to-ground (+CG) flashes occurred; (4) analysis of extremely low frequency (ELF) wave forms; and (5) an assessment of a cloud -ground strike location system using a combination of mobile laboratory and fixed-base TV video data.

  15. Plasmaspheric hiss intensity variations during magnetic storms

    NASA Technical Reports Server (NTRS)

    Smith, E. J.; Frandsen, A. M. A.; Tsurutani, B. T.; Thorne, R. M.; Chan, K. W.

    1974-01-01

    The storm time intensity variations of ELF electromagnetic emissions have been studied by using the Ogo 6 search coil magnetometer. Low-latitude signals exhibit a sharp low-frequency cutoff and are identified as plasmaspheric hiss. Such waves show pronounced intensification during the recovery phase of magnetic storms but remain close to background levels during the storm main phase. This behavior is consistent with cyclotron resonant generation within the plasmasphere as the latter expands into the intensified belt of outer zone electrons during the storm recovery.

  16. A simplified wave enhancement criterion for moving extreme events

    NASA Astrophysics Data System (ADS)

    Kudryavtsev, Vladimir; Golubkin, Pavel; Chapron, Bertrand

    2015-11-01

    An analytical model is derived to efficiently describe the wave energy distribution along the main transects of a moving extreme weather event. The model essentially builds on a generalization of the self-similar wave growth model and the assumption of a strongly dominant single spectral mode in a given quadrant of the storm. The criterion to anticipate wave enhancement with the generation of trapped abnormal waves defined as gr/ur2≈cT>(ur/V>)1/q, with r, u, and V, radial distance, average sustained wind speed, and translation velocity, respectively. Constants q and cT follow the fetch-law definitions. If forced during a sufficient time scale interval, also defined from this generalized self-similar wave growth model, waves can be trapped and large amplification of the wave energy will occur in the front-right storm quadrant. Remarkably, the group velocity and corresponding wavelength of outrunning wave systems will become wind speed independent and solely related to the translating velocity. The resulting significant wave height also only weakly depends on wind speed, and more strongly on the translation velocity. Compared to altimeter satellite measurements, the proposed analytical solutions for the wave energy distribution demonstrate convincing agreement. As analytically developed, the wave enhancement criterion can provide a rapid evaluation to document the general characteristics of each storm, especially the expected wavefield asymmetry.

  17. Storm impact scale for barrier islands

    USGS Publications Warehouse

    Sallenger, A.H., Jr.

    2000-01-01

    A new scale is proposed that categorizes impacts to natural barrier islands resulting from tropical and extra-tropical storms. The proposed scale is fundamentally different than existing storm-related scales in that the coupling between forcing processes and the geometry of the coast is explicitly included. Four regimes, representing different levels of impact, are defined. Within each regime, patterns and relative magnitudes of net erosion and accretion are argued to be unique. The borders between regimes represent thresholds defining where processes and magnitudes of impacts change dramatically. Impact level 1 is the 'swash' regime describing a storm where runup is confined to the foreshore. The foreshore typically erodes during the storm and recovers following the storm; hence, there is no net change. Impact level 2 is the 'collision' regime describing a storm where the wave runup exceeds the threshold of the base of the foredune ridge. Swash impacts the dune forcing net erosion. Impact level 3 is the 'overwash' regime describing a storm where wave runup overtops the berm or, if present, the foredune ridge. The associated net landward sand transport contributes to net migration of the barrier landward. Impact level 4 is the 'inundation' regime describing a storm where the storm surge is sufficient to completely and continuously submerge the barrier island. Sand undergoes net landward transport over the barrier island; limited evidence suggests the quantities and distance of transport are much greater than what occurs during the 'overwash' regime.

  18. Reduced Baroclinicity During Martian Global Dust Storms

    NASA Astrophysics Data System (ADS)

    Battalio, Joseph; Szunyogh, Istvan; Lemmon, Mark

    2015-11-01

    The eddy kinetic energy equation is applied to the Mars Analysis Correction Data Assimilation (MACDA) dataset during the pre-winter solstice period for the northern hemisphere of Mars. Traveling waves are triggered by geopotential flux convergence, grow baroclinically, and decay barotropically. Higher optical depth increases the static stability, which reduces vertical and meridional heat fluxes. Traveling waves during a global dust storm year develop a mixed baroclinic/barotropic growth phase before decaying barotropically. Baroclinic energy conversion is reduced during the global dust storm, but eddy intensity is undiminished. Instead, the frequency of storms is reduced due to a stabilized vertical profile.

  19. Tropical Storm Katrina

    Atmospheric Science Data Center

    2014-05-15

    ... title:  Cloud Spirals and Outflow in Tropical Storm Katrina     View Larger Image ... heights and cloud-tracked wind velocities for Tropical Storm Katrina, as the center of the storm was situated over the Tennessee ...

  20. Maps of the MY 25 Planet-encircling Dust Storm

    NASA Astrophysics Data System (ADS)

    Noble, J.; Cantor, B. A.; Wilson, R. J.; Haberle, R. M.; Bridger, A. F. C.; Barnes, J.; Hollingsworth, J. L.; Kahre, M. A.

    2015-12-01

    We have created 42 daily maps of the MY 25 planet-encircling dust storm (Ls=165-188) in order to better delimit the areal extent of storms observed by the Mars Orbiter Camera (MOC). These maps allow us to better compare storm evolution with eddies observed in Fast Fourier Synoptic Mapping (FFSM) of Thermal Emission Spectrometer (TES) temperatures. FFSM analysis of TES 3.7 hPa thermal data shows the presence of eastward traveling waves from 40 - 60° S with a period of about three sols. These maps use a new dust characterization scheme that categorizes dust storms and dust entrained in gravity waves by degree of (visual) structure. Preliminary analysis of these data indicate concurrent eastward migration of both storms and eddies. We hypothesize that these waves are transient baroclinic eddies that contributed to the initiation of precursor storms near Hellas.

  1. Solar radio continuum storms

    NASA Technical Reports Server (NTRS)

    Sakurai, K.

    1976-01-01

    The paper reviews the current status of research on solar radio continuum emissions from metric to hectometric wave frequencies, emphasizing the role of energetic electrons in the 10-100 keV range in these emissions. It is seen that keV-energy electrons generated in active sunspot groups must be the sources of radio continuum storm emissions for wide frequency bands. These electrons excite plasma oscillations in the medium, which in turn are converted to electromagnetic radiation. The radio noise continuum sources are usually associated with type III burst activity observed above these sources. Although the mechanism for the release of the energetic electrons is not known, it seems they are ejected from storm source regions in association with rapid variation of associated sunspot magnetic fields due to their growth into complex types. To explain some of the observed characteristics, the importance of two-stream instability and the scattering of ambient plasma ions on energetic electron streams is pointed out.

  2. Meiotic abnormalities

    SciTech Connect

    1993-12-31

    Chapter 19, describes meiotic abnormalities. These include nondisjunction of autosomes and sex chromosomes, genetic and environmental causes of nondisjunction, misdivision of the centromere, chromosomally abnormal human sperm, male infertility, parental age, and origin of diploid gametes. 57 refs., 2 figs., 1 tab.

  3. Tropical Storm Bud

    Atmospheric Science Data Center

    2013-04-19

    article title:  A Strengthening Eastern Pacific Storm     View Larger Image ... Imaging SpectroRadiometer (MISR) show then Tropical Storm Bud as it was intensifying toward hurricane status, which it acquired ...

  4. Craniofacial Abnormalities

    MedlinePlus

    ... of the skull and face. Craniofacial abnormalities are birth defects of the face or head. Some, like cleft ... palate, are among the most common of all birth defects. Others are very rare. Most of them affect ...

  5. Chromosome Abnormalities

    MedlinePlus

    ... decade, newer techniques have been developed that allow scientists and doctors to screen for chromosomal abnormalities without using a microscope. These newer methods compare the patient's DNA to a normal DNA ...

  6. Walking abnormalities

    MedlinePlus

    ... include: Arthritis of the leg or foot joints Conversion disorder (a psychological disorder) Foot problems (such as a ... injuries. For an abnormal gait that occurs with conversion disorder, counseling and support from family members are strongly ...

  7. Nail abnormalities

    MedlinePlus

    Beau's lines; Fingernail abnormalities; Spoon nails; Onycholysis; Leukonychia; Koilonychia; Brittle nails ... Just like the skin, the fingernails tell a lot about your health: ... the fingernail. These lines can occur after illness, injury to ...

  8. [Hair shaft abnormalities].

    PubMed

    Itin, P H; Düggelin, M

    2002-05-01

    Hair shaft disorders may lead to brittleness and uncombable hair. In general the hair feels dry and lusterless. Hair shaft abnormalities may occur as localized or generalized disorders. Genetic predisposition or exogenous factors are able to produce and maintain hair shaft abnormalities. In addition to an extensive history and physical examination the most important diagnostic examination to analyze a hair shaft problem is light microscopy. Therapy of hair shaft disorders should focus to the cause. In addition, minimizing traumatic influences to hair shafts, such as dry hair with an electric dryer, permanent waves and dyes is important. A short hair style is more suitable for such patients with hair shaft disorders.

  9. Utilities weather the storm

    SciTech Connect

    Lihach, N.

    1984-11-01

    Utilities must restore power to storm-damaged transmission and distribution systems, even if it means going out in ice storms or during lightning and hurricane conditions. Weather forecasting helps utilities plan for possible damage as well as alerting them to long-term trends. Storm planning includes having trained repair personnel available and adjusting the system so that less power imports are needed. Storm damage response requires teamwork and cooperation between utilities. Utilities can strengthen equipment in storm-prone or vulnerable areas, but good data are necessary to document the incidence of lighning strikes, hurricanes, etc. 2 references, 8 figures.

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

    USGS Publications Warehouse

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

    2004-01-01

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

  11. The North Sea Andrea storm and numerical simulations

    NASA Astrophysics Data System (ADS)

    Bitner-Gregersen, E. M.; Fernandez, L.; Lefèvre, J. M.; Monbaliu, J.; Toffoli, A.

    2014-06-01

    A coupling of a spectral wave model with a nonlinear phase-resolving model is used to reconstruct the evolution of wave statistics during a storm crossing the North Sea on 8-9 November 2007. During this storm a rogue wave (named the Andrea wave) was recorded at the Ekofisk field. The wave has characteristics comparable to the well-known New Year wave measured by Statoil at the Draupner platform 1 January 1995. Hindcast data of the storm at the nearest grid point to the Ekofisk field are here applied as input to calculate the evolution of random realizations of the sea surface and its statistical properties. Numerical simulations are carried out using the Euler equations with a higher-order spectral method (HOSM). Results are compared with some characteristics of the Andrea wave record measured by the down-looking lasers at Ekofisk.

  12. Characterizing Extreme Ionospheric Storms

    NASA Astrophysics Data System (ADS)

    Sparks, L.; Komjathy, A.; Altshuler, E.

    2011-12-01

    Ionospheric storms consist of disturbances of the upper atmosphere that generate regions of enhanced electron density typically lasting several hours. Depending upon the storm magnitude, gradients in electron density can sometimes become large and highly localized. The existence of such localized, dense irregularities is a major source of positioning error for users of the Global Positioning System (GPS). Consequently, satellite-based augmentation systems have been implemented to improve the accuracy and to ensure the integrity of user position estimates derived from GPS measurements. Large-scale irregularities generally do not pose a serious threat to estimate integrity as they can be readily detected by such systems. Of greater concern, however, are highly localized irregularities that interfere with the propagation of a signal detected by a user measurement but are poorly sampled by the receivers in the system network. The most challenging conditions have been found to arise following disturbances of large magnitude that occur only rarely over the course of a solar cycle. These extremely disturbed conditions exhibit behavior distinct from moderately disturbed conditions and, hence, have been designated "extreme storms". In this paper we examine and compare the behavior of the extreme ionospheric storms of solar cycle 23 (or, more precisely, extreme storms occurring between January 1, 2000, and December 31, 2008), as represented in maps of vertical total electron content. To identify these storms, we present a robust means of quantifying the regional magnitude of an ionospheric storm. Ionospheric storms are observed frequently to occur in conjunction with magnetic storms, i.e., periods of geophysical activity as measured by magnetometers. While various geomagnetic indices, such as the disturbance storm time (Dst) and the planetary Kp index, have long been used to rank the magnitudes of distinct magnetic storms, no comparable, generally recognized index exists for

  13. Tropical Storm Iniki, Central Pacific

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Tropical Storm Iniki in the North Pacific (40.5N, 152.5W) was dissipating from hurricane status when this photo was taken. Two days prior, as a full fledged hurricane, with winds of about 150 mph and waves of over 15 ft., it swept over the Hawaiian island of Kauai. But, as Iniki moved over the colder waters of the North Pacific, it began to weaken as can be seen by the lack of a tight spiral gyre and the absence of an eye in the center.

  14. Wind waves in tropical cyclones: satellite altimeter observations and modeling

    NASA Astrophysics Data System (ADS)

    Golubkin, Pavel; Kudryavtsev, Vladimir; Chapron, Bertrand

    2016-04-01

    Results of investigation of wind-wave generation by tropical cyclones using satellite altimeter data are presented. Tropical cyclones are generally relatively small rapidly moving low pressure systems that are capable of generating severe wave conditions. Translation of a tropical cyclone leads to a prolonged period of time surface waves in the right sector remain under high wind forcing conditions. This effect has been termed extended fetch, trapped fetch or group velocity quasi-resonance. A tropical cyclone wave field is thus likely more asymmetrical than the corresponding wind field: wind waves in the tropical cyclone right sector are more developed with larger heights than waves in the left one. A dataset of satellite altimeter intersections of the Western Pacific tropical cyclones was created for 2010-2013. Data from four missions were considered, i.e., Jason-1, Jason-2, CryoSat-2, SARAL/AltiKa. Measurements in the rear-left and front-right sectors of tropical cyclones were examined for the presence of significant wave asymmetry. An analytical model is then derived to efficiently describe the wave energy distribution in a moving tropical cyclone. The model essentially builds on a generalization of the self-similar wave growth model and the assumption of a strongly dominant single spectral mode in a given quadrant of the storm. The model provides a criterion to anticipate wave enhancement with the generation of trapped abnormal waves. If forced during a sufficient timescale interval, also defined from this generalized self-similar wave growth model, waves can be trapped and large amplification of the wave energy will occur in the front-right storm quadrant. Remarkably, the group velocity and corresponding wavelength of outrunning wave systems will become wind speed independent and solely relate to the translating velocity. The resulting significant wave height also only weakly depends on wind speed, and more strongly on the translation velocity. Satellite

  15. Investigating the impact of surface wave breaking on modeling the trajectories of drifters in the northern Adriatic Sea during a wind-storm event

    USGS Publications Warehouse

    Carniel, S.; Warner, J.C.; Chiggiato, J.; Sclavo, M.

    2009-01-01

    An accurate numerical prediction of the oceanic upper layer velocity is a demanding requirement for many applications at sea and is a function of several near-surface processes that need to be incorporated in a numerical model. Among them, we assess the effects of vertical resolution, different vertical mixing parameterization (the so-called Generic Length Scale -GLS- set of k-??, k-??, gen, and the Mellor-Yamada), and surface roughness values on turbulent kinetic energy (k) injection from breaking waves. First, we modified the GLS turbulence closure formulation in the Regional Ocean Modeling System (ROMS) to incorporate the surface flux of turbulent kinetic energy due to wave breaking. Then, we applied the model to idealized test cases, exploring the sensitivity to the above mentioned factors. Last, the model was applied to a realistic situation in the Adriatic Sea driven by numerical meteorological forcings and river discharges. In this case, numerical drifters were released during an intense episode of Bora winds that occurred in mid-February 2003, and their trajectories compared to the displacement of satellite-tracked drifters deployed during the ADRIA02-03 sea-truth campaign. Results indicted that the inclusion of the wave breaking process helps improve the accuracy of the numerical simulations, subject to an increase in the typical value of the surface roughness z0. Specifically, the best performance was obtained using ??CH = 56,000 in the Charnok formula, the wave breaking parameterization activated, k-?? as the turbulence closure model. With these options, the relative error with respect to the average distance of the drifter was about 25% (5.5 km/day). The most sensitive factors in the model were found to be the value of ??CH enhanced with respect to a standard value, followed by the adoption of wave breaking parameterization and the particular turbulence closure model selected. ?? 2009 Elsevier Ltd.

  16. T wave pacing inducing electrical storm and multiple shocks in an ICD-recipient: a novel complication of the automatic gain control function.

    PubMed

    Jaoudé, Simon Abou; Salamé, Elie; Azar, Rabih; Kassab, Roland

    2003-12-01

    Implantable cardioverter-defibrillator (ICD) is highly effective in treating life-threatening ventricular arrhythmias, but it can also have proarrhythmic effect in some cases. We report the case of a 72 years old patient with an ischemic cardiomyopathy in whom an ICD was implanted for a poorly tolerated ventricular tachycardia (Profiles MD-Ventritex). Forty-eight hours after implantation, the patient suddenly received 15 successive shocks. ECG tracings and intracardiac EGM showed the presence of several VT episodes, all induced by the antibradycardia pacing of the ICD: the automatic gain control function of the device failed to detect ventricular premature beats in this patient, leading to a bradycardia pacing falling on the T wave and inducing multiple VTs and shocks.

  17. Dust storms: recent developments.

    PubMed

    Goudie, Andrew S

    2009-01-01

    Dust storms have a number of impacts upon the environment including radiative forcing, and biogeochemical cycling. They transport material over many thousands of kilometres. They also have a range of impacts on humans, not least on human health. In recent years the identification of source areas for dust storms has been an important area or research, with the Sahara (especially Bodélé) and western China being recognised as the strongest sources globally. Another major development has been the recognition of the degree to which dust storm activity has varied at a range of time scales, millennial, century, decadal, annual and seasonal.

  18. Hazards of geomagnetic storms

    USGS Publications Warehouse

    Herzog, D.C.

    1992-01-01

    Geomagnetic storms are large and sometimes rapid fluctuations in the Earth's magnetic field that are related to disturbances on the Sun's surface. Although it is not widely recognized, these transient magnetic disturbances can be a significant hazard to people and property. Many of us know that the intensity of the auroral lights increases during magnetic storms, but few people realize that these storms can also cause massive power outages, interrupt radio communications and satellite operations, increase corrosion in oil and gas pipelines, and lead to spuriously high rejection rates in the manufacture of sensitive electronic equipment. 

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

    PubMed Central

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

    2012-01-01

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

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

    PubMed

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

    2012-01-01

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

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

    PubMed

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

    2012-01-01

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

  2. Tropical Storm Faxai

    NASA Video Gallery

    NASA/JAXA's TRMM Satellite provided data of developing Tropical Storm Faxai to make this 3-D image that showed some towering thunderstorms in the area were reaching altitudes of up to 15.5km/~9.6 m...

  3. Tropical Storm Dolly Develops

    NASA Video Gallery

    This animation from NOAA's GOES-East satellite from Aug. 31-Sept. 2 shows the movement of a low pressure area from the western Caribbean Sea over the Yucatan Peninsula as it becomes Tropical Storm ...

  4. Powerful Midwest Storm System

    NASA Video Gallery

    This animation of imagery from NOAA’s GOES-13 satellite shows themovement of storm systems in the south central United States on May 20,2013. Warm, moist gulf air flowing across Texas, Oklahoma...

  5. Tropical Storm Don

    NASA Video Gallery

    GOES-13 data was compiled into an animation by the NASA GOES Project at NASA Goddard that shows the development of Tropical Storm Don in the southern Gulf of Mexico, west of Cuba. The animation run...

  6. Atmospheric circulation and storm events in the Baltic Sea

    NASA Astrophysics Data System (ADS)

    Surkova, G. V.; Arkhipkin, Victor S.; Kislov, Alexander V.

    2015-09-01

    The storm events in the Baltic Sea are examined in connection with the main weather patterns grouped into the circulation types (CTs), and their changes in present climate. A calendar of storms was derived from results of wave model SWAN (Simulating WAves Nearshore) experiments for 1948-2011. Based on this calendar, a catalogue of atmospheric sea level pressure (SLP) fields was prepared for CTs from the NCEP/NCAR dataset. SLP fields were then analyzed using a pattern recognition algorithm which employed empirical orthogonal decomposition and cluster analysis. For every CT we conducted an analysis of their seasonal and interannual changes, along with their role in storm event formation. An increase of the storm CTs' frequency in the second part of the 20th century was shown to be in a close agreement with teleconnection circulation patterns such as the Arctic Oscillation, North Atlantic Oscillation and the Scandinavian blocking.

  7. Fractal identification of supercell storms

    NASA Astrophysics Data System (ADS)

    Féral, Laurent; Sauvageot, Henri

    2002-07-01

    The most intense and violent form of convective storm is the supercell storm, usually associated with heavy rain, hail, and destructive gusty winds, downbursts, and tornadoes. Identifying a storm cell as a supercell storm is not easy. What is shown here, from radar data, is that when an ordinary, or multicell storm evolves towards the supercellular organization, its fractal dimension is modified. Whereas the fractal dimension of the ordinary convective storms, including multicell thunderstorms, is observed around 1.35, in agreement with previous results, the fractal dimension of supercell storms is found close to 1.07. This low value is due to the unicellular character of supercells. The present paper suggests that the fractal dimension is a parameter that should be considered to analyse the dynamical organization of a convective field and to detect and identify the supercell storms, either isolated or among a population of convective storms.

  8. On extreme geomagnetic storms

    NASA Astrophysics Data System (ADS)

    Cid, Consuelo; Palacios, Judith; Saiz, Elena; Guerrero, Antonio; Cerrato, Yolanda

    2014-10-01

    Extreme geomagnetic storms are considered as one of the major natural hazards for technology-dependent society. Geomagnetic field disturbances can disrupt the operation of critical infrastructures relying on space-based assets, and can also result in terrestrial effects, such as the Quebec electrical disruption in 1989. Forecasting potential hazards is a matter of high priority, but considering large flares as the only criterion for early-warning systems has demonstrated to release a large amount of false alarms and misses. Moreover, the quantification of the severity of the geomagnetic disturbance at the terrestrial surface using indices as Dst cannot be considered as the best approach to give account of the damage in utilities. High temporal resolution local indices come out as a possible solution to this issue, as disturbances recorded at the terrestrial surface differ largely both in latitude and longitude. The recovery phase of extreme storms presents also some peculiar features which make it different from other less intense storms. This paper goes through all these issues related to extreme storms by analysing a few events, highlighting the March 1989 storm, related to the Quebec blackout, and the October 2003 event, when several transformers burnt out in South Africa.

  9. Boulders moved by tsunamis and storms: Insights from a new equation of motion

    NASA Astrophysics Data System (ADS)

    Weiss, R.; Diplas, P.

    2013-12-01

    Boulders can move during storms and tsunamis. However, it is a non-trivial problem to find a clear method to distinguish boulders moved by tsunami waves from those moved in storms in the field, but also in theory. This contribution is motivated the ongoing discussion about methods on how to find out if a boulder was moved by a tsunami or storm. We solve Newton's Second Law of Motion in polar coordinates and apply general conclusions of the Impulse Theory for Incipient Motion. We find that the boulder incipient motion and dislodgement is not only a function of the causative wave, but also of the roughness in the vicinity of the boulder and the slope angle. We employ the difference in the time of dislodgement in a tsunami and storm as a measure of how similar the storm and tsunami amplitudes are. If the roughness around the boulder is small, we conclude that it is impossible to find any method to discriminate between storm and tsunami waves. However, if the roughness is larger, amplitudes of storm waves and tsunami waves can be inverted, for example, with Nott's Equations. If the difference between the times to dislodgement is small or large depends also on the slope. For practical purposes, it is necessary to know the pre-transport setting of the boulder in terms of roughness and slope angle with confidence in order to be able to invert meaningful amplitudes of causative tsunami or storm waves, for example, with equations derived by Nott (2003).

  10. A Coastal Storms Intensity Scale for the Catalan Sea

    NASA Astrophysics Data System (ADS)

    Mendoza, E. T.; Jimenez, J. A.

    2009-09-01

    The impact of storms on the coastal zone produces a series of high-intensity processes such as beach erosion, overwash and inundation, usually considered as coastal hazards. When these coastal hazards verify along developed/urbanized areas, could produce large damages in existing infrastructures, affect coastal uses and disturb coastal ecosystem services. The importance of these storms and induced hazards is explicit in the Protocol on ICZM in the Mediterranean signed in 2008 by the EU and the Mediterranean countries. This Protocol includes a specific chapter on natural hazards, where the parties are advised to undertake vulnerability and hazard assessments of coastal zones and take prevention, mitigation and adaptation measures to address the effects of natural disasters. Within this context, the main aim of this work is to present an intensity scale for coastal storms developed for typical conditions of the Catalan Shelf. This follows the classic works of the hurricane (Saffir-Simpson, 1971) and the Atlantic Northeast storms (Dolan-Davis, 1992) scales although adapting them to the characteristics of Mediterranean coastal wave storms. To develop such scale, wave data recorded along the Catalan coast in 5 locations covering a coastline of about 400 km have been used. Recorded wave time series cover a total time frame of about 25 years (1984-2008). The first task was to identify storms in time series, which here were defined as those events during which the significant wave height exceeded a minimum value (threshold) of 2 m during a minimum period of 6 hours. Because our interest is to use this information to help managers to deal with coastal hazards, this definition was based not just in statistical properties of time series but on physical ones, i.e. this is the minimum event producing a significant coastal response in terms of beach erosion (estimated by means of numerical modelling of beach response to storm impacts). With this, a complete storm data set for

  11. Storm Warning Service

    NASA Technical Reports Server (NTRS)

    1993-01-01

    A Huntsville meteorologist of Baron Services, Inc. has formed a commercial weather advisory service. Weather information is based on data from Marshall Space Flight Center (MSFC) collected from antennas in Alabama and Tennessee. Bob Baron refines and enhances MSFC's real time display software. Computer data is changed to audio data for radio transmission, received by clients through an antenna and decoded by computer for display. Using his service, clients can monitor the approach of significant storms and schedule operations accordingly. Utilities and emergency management officials are able to plot a storm's path. A recent agreement with two other companies will promote continued development and marketing.

  12. Tropical Storm near Bermuda

    NASA Technical Reports Server (NTRS)

    1992-01-01

    This unnamed tropical storm near Bermuda (26.5N, 59.5W) was the result of a strong mid-latitude low pressure system that formed over the Gulf Stream near Cape Hatteras. It rapidly developed into a spiral gyre with internal wind speeds of up to 50 knots and whipped up the sea surface with swells of 15 to 20 feet creating dangerous boating conditions. These sub-hurricane storms are frequent occurances in this region during the fall, winter and spring.

  13. North Polar Dust Storm

    NASA Technical Reports Server (NTRS)

    2003-01-01

    MGS MOC Release No. MOC2-334, 18 April 2003

    This composite of Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) wide angle daily global images shows a north polar dust storm on March 7, 2003. Similar late summer storms occurred nearly every day from late February well into April 2003; these were also seen in late summer in 1999 and 2001. The white features at the top of the image are the water ice surfaces of the north polar residual cap. Sunlight illuminates the scene from the lower left.

  14. Analysis of TES FFSM Eddies and MOC Dust Storms, MY 24 - 26

    NASA Astrophysics Data System (ADS)

    Noble, J.; Wilson, R.; Haberle, R. M.; Bridger, A. F.; Hollingsworth, J. L.; Kahre, M. A.; Barnes, J.; Cantor, B. A.

    2013-12-01

    Mars Global Surveyor (MGS) orbiter observed a planet-encircling dust storm (PDS) in Mars year (MY) 25 from Ls=176.2-263.4°. We present an examination of Mars Orbiter Camera (MOC) dust storms and transient baroclinic eddies identified from Fast Fourier Synoptic Mapping (FFSM) of Thermal Emission Spectrometer (TES) temperatures for the first two phases of the storm: precursor, Ls=176.2- 184.7°, and expansion, Ls=184.7-193°. FFSM analysis of TES 3.7 hPa thermal data shows the presence of eastward traveling waves at 60° S with a period of about three sols. We hypothesize that these waves are transient baroclinic eddies that contributed to the initiation of precursor storms near Hellas. Integration of FFSM and MOC MY 24 and 25 data shows interesting temporal and spatial associations between the evolution of eddies and storms, including: 1) comparable periodicities of travelling waves and pulses of storm activity; 2) concurrent eastward propagation of both eddies and storms; and 3) structured spatial relationship where high-latitude storms tend to occur on the eastern side of the eddy, while lower (and some middle) latitude storms occur on the western. These results suggest a causal relationship between baroclinic eddies and local storm initiation. New MY 26 results will be presented.

  15. Analysis of TES FFSM Eddies and MOC Dust Storms, MY 24 - 26

    NASA Astrophysics Data System (ADS)

    Noble, J.; Haberle, R. M.; Bridger, A. F.; Wilson, R.; Barnes, J.; Hollingsworth, J.; Kahre, M. A.; Cantor, B. A.

    2012-12-01

    Mars Global Surveyor (MGS) orbiter observed a planet-encircling dust storm (PDS) in Mars year (MY) 25 from Ls=176.2-263.4°. We present an examination of Mars Orbiter Camera (MOC) dust storms and transient baroclinic eddies identified from Fast Fourier Synoptic Mapping (FFSM) of Thermal Emission Spectrometer (TES) temperatures for the first two phases of the storm: precursor, Ls=176.2- 184.7°, and expansion, Ls=184.7-193°. FFSM analysis of TES 3.7 hPa thermal data shows the presence of eastward-traveling waves at 60° S with a period of about three sols. We hypothesize that these waves are transient baroclinic eddies that contributed to the initiation of precursor storms near Hellas. Integration of FFSM and MOC MY 24 and 25 data shows interesting temporal and spatial associations between the evolution of eddies and storms, including: 1) comparable periodicities of travelling waves and pulses of storm activity; 2) concurrent eastward propagation of both eddies and storms; and 3) structured spatial relationship where high-latitude storms tend to occur on the eastern side of the eddy, while lower (and some middle) latitude storms occur on the western. These results suggest a causal relationship between baroclinic eddies and local storm initiation. New MY 26 results will be presented.lt;img border=0 src="images/P22A-03_B.jpg">

  16. Tropical Storm Lee to Newfoundland

    NASA Video Gallery

    This video shows Tropical Storm Lee as it made landfall in Louisiana and Mississippi on September 4, 2011. This storm produced flooding and tornadoes to the southern states all the way to flooding ...

  17. Observing Storm Surges from Space: A New Opportunity

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

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

  18. Recovery from major storms

    SciTech Connect

    Holeman, J.S.

    1980-01-01

    Public Service Company of Oklahoma's transmission and distribution system is in tornado alley, and it seems the number of tornados hitting some part of the system is increasing each year. In the past 30 years, Tulsa his been hit 7 times, and experienced 3 very wide and destructive tornado storm systems between 1971 and 1975.

  19. STORM INLET FILTRATION DEVICE

    EPA Science Inventory

    Five field tests were conducted to evaluate the effectiveness of the Storm and Groundwater Enhancement Systems (SAGES) device for removing contaminants from stormwater. The SAGES device is a three-stage filtering system that could be used as a best management practices (BMP) retr...

  20. California's Perfect Storm

    ERIC Educational Resources Information Center

    Bacon, David

    2010-01-01

    The United States today faces an economic crisis worse than any since the Great Depression of the 1930s. Nowhere is it sharper than in the nation's schools. Last year, California saw a perfect storm of protest in virtually every part of its education system. K-12 teachers built coalitions with parents and students to fight for their jobs and their…

  1. Weathering the storm

    SciTech Connect

    Burr, M.T.

    1993-02-01

    When Hurricane Andrew struck, thousands were displaced from their homes in Florida and Louisiana. Now, months after the winds ceased blowing, the storm is causing hardship once again. Insurance companies sustaining large losses in recent months from a number of natural disasters - including the hurricane - are now passing those losses on to their customers. Independent power companies are no exception.

  2. Stories from the Storm

    ERIC Educational Resources Information Center

    Smoczynski, Carol

    2007-01-01

    For four months, St. Paul's Episcopal School in the Lakeview neighborhood of New Orleans, Louisiana remained closed after Hurricane Katrina ravaged the entire city in August 2005. The storm left St. Paul's campus under nine feet of water for two weeks, destroying many buildings and the entire first floor of the campus. As the only remaining art…

  3. Reducing uncertainty - responses for electricity utilities to severe solar storms

    NASA Astrophysics Data System (ADS)

    Gaunt, Charles Trevor

    2014-01-01

    Until recently, electricity utilities in mid- and low-latitude regions believed that solar storms had no (or only insignificant) effect on their power systems. Then it was noticed that the onset of damage in several large transformers, leading to their failure, correlated very closely with the Halloween storm of 2003. Since then engineers have started to appreciate that a very severe storm could have serious consequences outside the high-latitude regions. There are many uncertainties in predicting the effects of solar storms on electrical systems. The severity and time of arrival of a storm are difficult to model; so are the geomagnetically induced currents (GICs) expected to flow in the power networks. Published information about the responses of different types of transformers to GICs is contradictory. Measurements of the abnormal power flows in networks during solar storms generally do not take into account the effects of the current distortion and unbalance, potentially giving misleading signals to the operators. The normal requirement for optimum system management, while allowing for the possibility of faults caused by lightning, birds and other causes, limits the capacity of system operators to respond to the threats of GICs, which are not assessed easily by the N - 1 reliability criterion. A utility's response to the threat of damage by GICs depends on the expected frequency and magnitude of solar storms. Approaches to formulating a response are located in a system model incorporating space physics, network analysis, transformer engineering, network reliability and decision support and the benefits are identified. Approaches adopted in high-latitude regions might not be appropriate where fewer storms are expected to reach damaging levels. The risks of an extreme storm cannot be ignored, and understanding the response mechanisms suitable for low-latitude regions has the capacity to inform and reduce the uncertainty for power systems planners and operators

  4. Behavior of the terminal T wave during exercise in normal subjects, patients with symptomatic coronary artery disease and apparently healthy subjects with abnormal ST segment depression.

    PubMed

    O'Donnell, J; Lovelace, D E; Knoebel, S B; McHenry, P L

    1985-01-01

    The Q-T interval and apex of T wave to end of T wave (aT-eT) interval were measured by computer in four age-matched study groups at rest and during exercise to determine whether: the behavior of the aT-eT interval differs in patients with myocardial ischemia when compared with normal subjects, and the behavior of the aT-eT interval differs in subjects with true positive and false positive ST segment responses. Group I consisted of 57 normal subjects. Group II consisted of 41 symptomatic patients with documented coronary artery disease. A group of apparently healthy subjects with asymptomatic ST segment depression during exercise was divided into two additional groups: Group III, those without coronary artery disease; and Group IV, those with coronary artery disease. Subjects were excluded from the study if they had left ventricular hypertrophy or an intraventricular conduction defect or were taking digitalis or type I antiarrhythmic agents. There were no significant differences in the aT-eT interval and aT-eT/Q-T ratio among the four study groups when compared at rest; however, during exercise at similar heart rates, the aT-eT interval was significantly shorter and the aT-eT/Q-T ratio significantly smaller in Groups II and IV, the subjects with coronary artery disease, than in Group I, the normal subjects. The aT-eT interval and aT-eT/Q-T ratio measurements in Group III did not differ from those in Group I at rest or during exercise. In conclusion, the aT-eT interval and aT-eT/Q-T ratio may reflect changes in myocardial repolarization in exercise-induced ischemia and may have potential for future clinical application.

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  6. Historic and Future Ice Storms

    NASA Astrophysics Data System (ADS)

    Klima, K.; Morgan, M. G.

    2014-12-01

    Ice storm losses from business interruption as well as transportation and health damages can range into billions of dollars. For instance, the December 2008 New England and Upstate New York ice storm caused four deaths and monetary damages between 2.5 and 3.7 billion, and the 2008 Chinese winter storms resulted in over 130 deaths and over 20 billion in damages. Informal discussions with ice storm experts indicate that due to competing temperature and precipitation effects as well as local topographic effects, it is unclear how exactly climate change will affect ice storms. Here we ask how incident frequencies might change in a future climate at four weather stations prone to ice storms. Using historical atmospheric soundings, we conduct a thought experiment where we perturb the temperatures as might be expected in a future climate. We then discuss changes in monthly frequency of ice storms.

  7. Storm water pollution prevention plans

    SciTech Connect

    Rossmiller, R.L. )

    1993-03-01

    National Pollutant Discharge Elimination System (NPDES) general permit applications for industrial storm water discharge were to have been filed by October 1992. The Environmental Protection Agency (EPA) and state agencies are now issuing permits based on these applications. One compliance aspect of the permits is the Storm Water Pollution Prevention Plan (SWP3). The plan must identify the facility's potential sources of storm water pollution and develop and implement best management practices (BMPs) to reduce pollutants in storm water runoff. The objectives of the NPDES storm water program are to eliminate illegal dumping and illicit connections, and to reduce pollutants in industrial storm water discharge. These regulations require industry to develop detailed facility site maps, and describe the types, amounts and locations of potential pollutants. Based on this information, industry can develop and implement best management practices to reduce pollutants in storm water runoff.

  8. Distant storms as drivers of environmental change at Pacific atolls.

    PubMed

    Gardner, Jonathan P A; Garton, David W; Collen, John D; Zwartz, Daniel

    2014-01-01

    The central Pacific Ocean with its many low lying islands and atolls is under threat from sea level rise and increased storm activity. Here, we illustrate how increasing frequency and severity of large scale storm events associated with global climate change may be particularly profound at the local scale for human populations that rely on lagoon systems for provision of a variety of goods and services. In August 2011 a storm originating in the Southern Ocean caused a large amplitude ocean swell to move northward through the Pacific Ocean. Its arrival at Palmyra Atoll coincided with transient elevated sea surface height and triggered turnover of the lagoon water column. This storm-induced change to the lagoon reflects long distance connectivity with propagated wave energy from the Southern Ocean and illustrates the increasing threats generated by climate change that are faced by human populations on most low-lying Pacific islands and atolls. PMID:24498232

  9. Distant storms as drivers of environmental change at Pacific atolls.

    PubMed

    Gardner, Jonathan P A; Garton, David W; Collen, John D; Zwartz, Daniel

    2014-01-01

    The central Pacific Ocean with its many low lying islands and atolls is under threat from sea level rise and increased storm activity. Here, we illustrate how increasing frequency and severity of large scale storm events associated with global climate change may be particularly profound at the local scale for human populations that rely on lagoon systems for provision of a variety of goods and services. In August 2011 a storm originating in the Southern Ocean caused a large amplitude ocean swell to move northward through the Pacific Ocean. Its arrival at Palmyra Atoll coincided with transient elevated sea surface height and triggered turnover of the lagoon water column. This storm-induced change to the lagoon reflects long distance connectivity with propagated wave energy from the Southern Ocean and illustrates the increasing threats generated by climate change that are faced by human populations on most low-lying Pacific islands and atolls.

  10. Distant Storms as Drivers of Environmental Change at Pacific Atolls

    PubMed Central

    Gardner, Jonathan P. A.; Garton, David W.; Collen, John D.; Zwartz, Daniel

    2014-01-01

    The central Pacific Ocean with its many low lying islands and atolls is under threat from sea level rise and increased storm activity. Here, we illustrate how increasing frequency and severity of large scale storm events associated with global climate change may be particularly profound at the local scale for human populations that rely on lagoon systems for provision of a variety of goods and services. In August 2011 a storm originating in the Southern Ocean caused a large amplitude ocean swell to move northward through the Pacific Ocean. Its arrival at Palmyra Atoll coincided with transient elevated sea surface height and triggered turnover of the lagoon water column. This storm-induced change to the lagoon reflects long distance connectivity with propagated wave energy from the Southern Ocean and illustrates the increasing threats generated by climate change that are faced by human populations on most low-lying Pacific islands and atolls. PMID:24498232

  11. Electrocardiograph abnormalities in intracerebral hemorrhage.

    PubMed

    Takeuchi, Satoru; Nagatani, Kimihiro; Otani, Naoki; Wada, Kojiro; Mori, Kentaro

    2015-12-01

    This study investigated the prevalence and type of electrocardiography (ECG) abnormalities, and their possible association with the clinical/radiological findings in 118 consecutive patients with non-traumatic, non-neoplastic intracerebral hemorrhage (ICH). ECG frequently demonstrates abnormalities in patients with ischemic stroke and subarachnoid hemorrhage, but little is known of ECG changes in ICH patients. Clinical and radiological information was retrospectively reviewed. ECG recordings that were obtained within 24 hours of the initial hemorrhage were analyzed. Sixty-six patients (56%) had one or more ECG abnormalities. The most frequent was ST depression (24%), followed by left ventricular hypertrophy (20%), corrected QT interval (QTc) prolongation (19%), and T wave inversion (19%). The logistic regression analysis demonstrated the following: insular involvement was an independent predictive factor of ST depression (p<0.001; odds ratio OR 10.18; 95% confidence interval [CI] 2.84-36.57); insular involvement (p<0.001; OR 23.98; 95% CI 4.91-117.11) and presence of intraventricular hemorrhage (p<0.001; OR 8.72; 95% CI 2.69-28.29) were independent predictive factors of QTc prolongation; deep hematoma location (p<0.001; OR 19.12; 95% CI 3.82-95.81) and hematoma volume >30 ml (p=0.001; OR 6.58; 95% CI 2.11-20.46) were independent predictive factors of T wave inversion. We demonstrate associations between ECG abnormalities and detailed characteristics of ICH.

  12. Thyroid Storm Complicated by Bicytopenia and Disseminated Intravascular Coagulation

    PubMed Central

    Tokushima, Yoshinori; Sakanishi, Yuta; Nagae, Kou; Tokushima, Midori; Tago, Masaki; Tomonaga, Motosuke; Yoshioka, Tsuneaki; Hyakutake, Masaki; Sugioka, Takashi; Yamashita, Shu-ichi

    2014-01-01

    Patient: Male, 23 Final Diagnosis: Thyroid storm Symptoms: Delirium • diarrhea • fever • hypertension • hyperventilation • tachycardia • weight loss Medication: — Clinical Procedure: — Specialty: Endocrinology and Metabolic Objective: Unusual clinical course Background: The clinical presentation of thyroid storm includes fever, tachycardia, hypertension, and neurological abnormalities. It is a serious condition with a high mortality rate. Furthermore, some other complications affect the clinical course of thyroid storm. Although it is reported that prognosis is poor when thyroid storm is complicated by disseminated intravascular coagulation syndrome (DIC) and leukopenia, reports of such cases are rare. Case Report: A 23-year-old man presented with delirium, high pyrexia, diarrhea, and weight loss of 18 kg over 2 months. According to the criteria of Burch and Wartofsky, he was diagnosed with thyroid storm on the basis of his symptom-complex and laboratory data that confirmed the presence of hyperthyroidism. Investigations also found leukopenia, thrombocytopenia, and disseminated intravascular coagulation, all of which are very rare complications of thyroid storm. We successfully treated him with combined therapy including anti-thyroid medication, despite leukopenia. Conclusions: Early diagnosis and treatment are essential in ensuring a good outcome for patients with this rare combination of medical problems. PMID:25072662

  13. Extreme Geomagnetic Storms - 1868 - 2010

    NASA Astrophysics Data System (ADS)

    Vennerstrom, S.; Lefevre, L.; Dumbović, M.; Crosby, N.; Malandraki, O.; Patsou, I.; Clette, F.; Veronig, A.; Vršnak, B.; Leer, K.; Moretto, T.

    2016-05-01

    We present the first large statistical study of extreme geomagnetic storms based on historical data from the time period 1868 - 2010. This article is the first of two companion papers. Here we describe how the storms were selected and focus on their near-Earth characteristics. The second article presents our investigation of the corresponding solar events and their characteristics. The storms were selected based on their intensity in the aa index, which constitutes the longest existing continuous series of geomagnetic activity. They are analyzed statistically in the context of more well-known geomagnetic indices, such as the Kp and Dcx/Dst index. This reveals that neither Kp nor Dcx/Dst provide a comprehensive geomagnetic measure of the extreme storms. We rank the storms by including long series of single magnetic observatory data. The top storms on the rank list are the New York Railroad storm occurring in May 1921 and the Quebec storm from March 1989. We identify key characteristics of the storms by combining several different available data sources, lists of storm sudden commencements (SSCs) signifying occurrence of interplanetary shocks, solar wind in-situ measurements, neutron monitor data, and associated identifications of Forbush decreases as well as satellite measurements of energetic proton fluxes in the near-Earth space environment. From this we find, among other results, that the extreme storms are very strongly correlated with the occurrence of interplanetary shocks (91 - 100 %), Forbush decreases (100 %), and energetic solar proton events (70 %). A quantitative comparison of these associations relative to less intense storms is also presented. Most notably, we find that most often the extreme storms are characterized by a complexity that is associated with multiple, often interacting, solar wind disturbances and that they frequently occur when the geomagnetic activity is already elevated. We also investigate the semiannual variation in storm occurrence

  14. Severe storm electricity

    NASA Technical Reports Server (NTRS)

    Arnold, R. T.; Rust, W. D.

    1984-01-01

    Successful ground truth support of U-2 overflights was been accomplished. Data have been reduced for 4 June 1984 and some of the results have been integrated into some of MSFC's efforts. Staccato lightning (multiply branched, single stroke flash with no continuing current) is prevalent within the rainfree region around the main storm updraft and this is believed to be important, i.e., staccato flashes might be an important indicator of severe storm electrification. Results from data analysis from two stations appear to indicate that charge center heights can be estimated from a combination of intercept data with data from the fixed laboratory at NSSL. An excellent data base has been provided for determining the sight errors and efficiency of NSSL's LLP system. Cloud structures, observable in a low radar reflectivity region and on a scale smaller than is currently resolved by radar, which appear to be related to electrical activity are studied.

  15. Dust Storm, Aral Sea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The Aral Sea has shrunk to less than half its size since 1985. The Aral Sea receives little water (sometimes no water) from the two major rivers that empty into it-the Syr Darya and Amu Darya. Instead, the river water is diverted to support irrigation for the region's extensive cotton fields. Recently, water scarcity has increased due to a prolonged drought in Central Asia. As the Aral Sea recedes, its former sea bed is exposed. The Aral's sea bed is composed of fine sediments-including fertilizers and other agricultural chemicals-that are easily picked up by the region's strong winds, creating thick dust storms. The International Space Station crew observed and recorded a large dust storm blowing eastward from the Aral Sea in late June 2001. This image illustrates the strong coupling between human activities (water diversions and irrigation), and rapidly changing land, sea and atmospheric processes-the winds blow across the

  16. Development in the STORM.

    PubMed

    Kamiyama, Daichi; Huang, Bo

    2012-12-11

    The recent invention of superresolution microscopy has brought up much excitement in the biological research community. Here, we focus on stochastic optical reconstruction microscopy/photoactivated localization microscopy (STORM/PALM) to discuss the challenges in applying superresolution microscopy to the study of developmental biology, including tissue imaging, sample preparation artifacts, and image interpretation. We also summarize new opportunities that superresolution microscopy could bring to the field of developmental biology. PMID:23237944

  17. Ice Storm Supercomputer

    SciTech Connect

    2009-01-01

    "A new Idaho National Laboratory supercomputer is helping scientists create more realistic simulations of nuclear fuel. Dubbed 'Ice Storm,' this 2048-processor machine allows researchers to model and predict the complex physics behind nuclear reactor behavior. And with a new visualization lab, the team can see the results of its simulations on the big screen." For more information about INL research, visit http://www.facebook.com/idahonationallaboratory.

  18. Ice Storm Supercomputer

    ScienceCinema

    None

    2016-07-12

    "A new Idaho National Laboratory supercomputer is helping scientists create more realistic simulations of nuclear fuel. Dubbed 'Ice Storm,' this 2048-processor machine allows researchers to model and predict the complex physics behind nuclear reactor behavior. And with a new visualization lab, the team can see the results of its simulations on the big screen." For more information about INL research, visit http://www.facebook.com/idahonationallaboratory.

  19. Dust storm, northern Mexico

    NASA Technical Reports Server (NTRS)

    1983-01-01

    This large dust storm along the left side of the photo, covers a large portion of the state of Coahuila, Mexico (27.5N, 102.0E). The look angle of this oblique photo is from the south to the north. In the foreground is the Sierra Madre Oriental in the states Coahuila and Nuevo Leon with the Rio Grande River, Amistad Reservoir and Texas in the background.

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

    NASA Astrophysics Data System (ADS)

    Lin, N.; Emanuel, K.

    2012-12-01

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

  1. Correlation between abnormal pore pressure and tectonic jointing in the Devonian Catskill Delta

    NASA Astrophysics Data System (ADS)

    Engelder, Terry; Oertel, Gerhard

    1985-12-01

    Using the preferred orientation of chlorite, we measured vertical compaction in 53 samples from the Devonian Catskill Delta in central New York State. The marine part of this delta contains three levels based on different amounts of vertical compaction. These levels correspond roughly to (1) black shales at the base, (2) prodelta turbidites, and (3) a cap of shallow-water sediments including abundant storm-washed shell hashes deposited within the wave base. The cap is normally compacted, whereas the lower two levels are undercompacted. Tectonic (cross-fold) joints that propagated during the late Paleozoic Alleghanian orogeny are restricted to the deeper, undercompacted levels of the Catskill Delta, whereas unloading (cross-fold) joints pervade the cap. The correlation between undercompaction and the distribution of tectonic joints indicates that abnormal fluid pressure was a key mechanism during the propagation of these joints.

  2. Teleseismic S wave microseisms.

    PubMed

    Nishida, Kiwamu; Takagi, Ryota

    2016-08-26

    Although observations of microseisms excited by ocean swells were firmly established in the 1940s, the source locations remain difficult to track. Delineation of the source locations and energy partition of the seismic wave components are key to understanding the excitation mechanisms. Using a seismic array in Japan, we observed both P and S wave microseisms excited by a severe distant storm in the Atlantic Ocean. Although nonlinear forcing of an ocean swell with a one-dimensional Earth model can explain P waves and vertically polarized S waves (SV waves), it cannot explain horizontally polarized S waves (SH waves). The precise source locations may provide a new catalog for exploring Earth's interior.

  3. Dolan and Davis (1992) Power Index: Application to Coastal Storm Events in Cadiz (SW Spain)

    NASA Astrophysics Data System (ADS)

    Rangel-Buitrago, Nelson; Anfuso, Giorgio

    2010-05-01

    Over the past centuries several great storms have caused important economic losses and scores of deaths along the coastline of the world. For the past 30 years, coastal scientists and the general public have used the Saffir-Simpson Scale to compare tropical cyclones. More recently, different indexes have been developed: they usually take into account wind and/or wave characteristics, duration of the storm, etc. In this study case, the Dolan and Davis (1992) Power Index was used to classify coastal storms in Cadiz littoral (SW Spain). The Index was calculated according to the formulation Hs2td, with Hs being the significant wave height and td the duration of the storm in hours. The index discriminates between 5 classes ranging from weak to extremes. Storm event was defined considering significant wave heights higher than 2.5 m and duration of 12 hours. Wave data were obtained from the prediction point 1054046 which belongs to the HIPOCAS network (data from January 1958 to December 2001). A total amount of 334 events was classified with 222 and 70 events respectively belonging to the weak and moderate classes. The significant, severe and extreme classes respectively presented 23, 11 and 8 events. Usually storm events took place from October to March, the most powerful storms taking place in December and January. Keywords: Storms, Coastal Erosion, Power Index, Cadiz.

  4. Midlatitude Storms in a Moister World: Lessons from Idealized Baroclinic Life Cycle Experiments

    NASA Astrophysics Data System (ADS)

    Booth, J.; Wang, S.; Polvani, L.

    2012-04-01

    In global warming projections, the response of midlatitude storms has varied, depending on model resolution and storm metric analyzed. One point of contention regarding the varied response relates to the impact of moisture, because Global Climate Models parameterize some portion of the moist physics of midlatitude storms. Therefore, this study examines the sensitivity of midlatitude storms to moisture using a baroclinic wave in a weather forecasting model. Additionally, this study focuses on multiple storm metrics: eddy kinetic energy (EKE), storm central pressure, and the extremes in precipitation and surface winds. We take two approaches to vary the model's moisture: (1) we vary the relative humidity in the initial conditions, and (2) we fix the initial relative humidity and alter the definition of the saturation vapor pressure. The second approach allows us to increase moisture content above the current levels, which is something that is expected in a warmer climate. In both of our experiments, the storm central pressure minimum and the extremes in surface winds and precipitation strengthen monotonically as moisture increases. However, the response is quite small for moisture levels equal to those projected for the 21st century in GCMs. The behavior of the storm EKE is more complicated: for moisture content values near and above current levels, EKE responds non-monotonically. This behavior is caused by a change in the storm's circulation: increasing moisture content increases the vertical slope of the storm warm conveyor belt, which decreases the meridional extent of the storm. This decrease in meridional scale weakens the EKE.

  5. Morphological impacts of extreme storms on sandy beaches and barriers

    USGS Publications Warehouse

    Morton, R.A.; Sallenger, A.H.

    2003-01-01

    Historical extreme storms that struck the Gulf Coast and Atlantic Coast regions of the United States caused several different styles of morphological response and resulted in a wide range of washover penetration distances. The post- storm erosional responses included dune scarps, channel incisions, and washouts, whereas depositional responses included perched fans, washover terraces, and sheetwash lineations. Maximum inland extent of washover penetration ranged from approximately 100 to 1000 m and estimated sediment volumes associated with these deposits ranged from about 10 to 225 m 3/m of beach. Unusual styles of morphological response (sheetwash lineations and incised channels) and maximum washover penetration distances are closely correlated, and they also correspond to storm intensity as denned by the Saffir-Simpson wind-speed scale. The regional morphological responses and washover penetration distances are controlled primarily by the interactions among heights and durations of storm surge relative to adjacent land elevations, differences in water levels between the ocean and adjacent lagoon, constructive and destructive interference of storm waves, and alongshore variations in nearshore bathymetry. For barrier segments that are entirely submerged during the storm, impacts can be enhanced by the combined influences of shallow water depths and organized flow within the wind field. The greatest washover penetrations and sediment accumulations are products of shallow water, confined flow, and high wind stress. Transport and deposition of washover sediments across barrier islands and into the adjacent lagoon are common processes along the Gulf of Mexico but not along the western Atlantic Ocean. This fundamental difference in storm impact underscores how microtidal and mesotidal barriers respond respectively to extreme storms, and provides insight into how different types of barrier islands will likely respond to future extreme storms and to a relative rise in sea

  6. Scaling coastal dune elevation changes across storm-impact regimes

    USGS Publications Warehouse

    Long, Joseph W.; de Bakker, Anouk T. M.; Plant, Nathaniel G.

    2014-01-01

    Extreme storms drive change in coastal areas, including destruction of dune systems that protect coastal populations. Data from four extreme storms impacting four geomorphically diverse barrier islands are used to quantify dune elevation change. This change is compared to storm characteristics to identify variability in dune response, improve understanding of morphological interactions, and provide estimates of scaling parameters applicable for future prediction. Locations where total water levels did not exceed the dune crest experienced elevation change of less than 10%. Regions where wave-induced water levels exceeded the dune crest exhibited a positive linear relationship between the height of water over the dune and the dune elevation change. In contrast, a negative relationship was observed when surge exceeded the dune crest. Results indicate that maximum dune elevation, and therefore future vulnerability, may be more impacted from lower total water levels where waves drive sediment over the dune rather than surge-dominated flooding events.

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

    USGS Publications Warehouse

    Morton, R.A.

    2002-01-01

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

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

    EPA Science Inventory

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

  9. Storm surges formation in the White and Barents Seas

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

  10. Accurately characterizing the importance of wave-particle interactions in radiation belt dynamics: The pitfalls of statistical wave representations

    NASA Astrophysics Data System (ADS)

    Murphy, Kyle R.; Mann, Ian R.; Rae, I. Jonathan; Sibeck, David G.; Watt, Clare E. J.

    2016-08-01

    Wave-particle interactions play a crucial role in energetic particle dynamics in the Earth's radiation belts. However, the relative importance of different wave modes in these dynamics is poorly understood. Typically, this is assessed during geomagnetic storms using statistically averaged empirical wave models as a function of geomagnetic activity in advanced radiation belt simulations. However, statistical averages poorly characterize extreme events such as geomagnetic storms in that storm-time ultralow frequency wave power is typically larger than that derived over a solar cycle and Kp is a poor proxy for storm-time wave power.

  11. Storm-Substorm Relations Workshop

    NASA Astrophysics Data System (ADS)

    Kan, Joe

    2006-06-01

    Magnetic storms in the magnetosphere can cause damage to communication satellites and large-scale power outages. The concept that a magnetic storm is a compilation of a series of substorms was proposed by Akasofu [1968]. However, Kamide [1992] showed that substorms are not a necessary condition for the occurrence of a magnetic storm. This controversy initiated a new era of research on the storm-substorm relation, which was the subject of a recent workshop in Banff, Alberta, Canada. The main topics discussed during the meeting included a brief overview of what a substorm is, how quasiperiodic substorm events and steady magnetospheric convection (SMC) events without substorms contribute to storms, and how plasma flows enhanced by magnetic reconnection in the plasma sheet contribute to substorms and storms.

  12. Lightning location relative to storm structure in a supercell storm and a multicell storm

    NASA Technical Reports Server (NTRS)

    Ray, Peter S.; Macgorman, Donald R.; Rust, W. David; Taylor, William L.; Rasmussen, Lisa Walters

    1987-01-01

    Relationships between lightning location and storm structure are examined for one radar volume scan in each of two mature, severe storms. One of these storms had characteristics of a supercell storm, and the other was a multicell storm. Data were analyzed from dual-Doppler radar and dual-VHF lightning-mapping systems. The distributions of VHF impulse sources were compared with radar reflectivity, vertical air velocity, and their respective gradients. In the supercell storm, lightning tended to occur along streamlines above and down-shear of the updraft and reflectivity cores; VHF impulse sources were most concentrated in reflectivities between 30 and 40 dBZ and were distributed uniformly with respect to updraft speed. In the multicell storm, on the other hand, lightning tended to coincide with the vertical reflectivity and updraft core and with the diverging streamlines near the top of the storm. The results suggest that the location of lightning in these severe storms were most directly associated with the wind field structure relative to updraft and reflectivity cores. Since the magnitude and vertical shear of the environmental wind are fundamental in determining the reflectivity and wind field structure of a storm, it is suggested that these environmental parameters are also fundamental in determining lightning location.

  13. Dawn-dusk asymmetry and adiabatic dynamic of the radiation belt electrons during magnetic storm

    NASA Astrophysics Data System (ADS)

    Lazutin, Leonid L.

    2016-09-01

    The changes of the latitudinal profiles of outer belt energetic electrons during magnetic storms are mostly explained by the precipitation into the loss cone caused by VLF and EMIC waves or by the scattering into the magnetopause. In present work, energetic electron dynamics during magnetic storm of August 29-30, 2004 we attributed at most to the adiabatic transformation of the magnetic drift trajectories and Dst effect. This conclusion was based on the analysis of dawn-dusk asymmetry of the electron latitudinal profiles measured by low altitude polar orbiter SERVIS-1 and on the coincidence of pre-storm and after-storm profiles of radiation belt electrons and protons.

  14. Ionospheric and satellite observations for studying the dynamic behavior of typhoons and the detection of severe storms and tsunamis

    NASA Technical Reports Server (NTRS)

    Hung, R. J.; Smith, R. E.

    1978-01-01

    Atmospheric acoustic-gravity waves associated with severe thunderstorms, tornadoes, typhoons (hurricanes) and tsunamis can be studied through the coupling between the ionosphere and the troposphere. Reverse ray tracing computations of acoustic-gravity waves observed by an ionospheric Doppler sounder array show that wave sources are in the nearby storm systems and that the waves are excited prior to the storms. Results show that ionospheric observations, together with satellite observations, can contribute to the understanding of the dynamical behavior of typhoons, severe storms and tsunamis.

  15. Tropical Storm Erin

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Location: The Atlantic Ocean 210 miles south of Galveston, Texas Categorization: Tropical Storm Sustained Winds: 40 mph (60 km/hr)

    [figure removed for brevity, see original site] [figure removed for brevity, see original site] Infrared ImageMicrowave Image

    Infrared Images Because infrared radiation does not penetrate through clouds, AIRS infrared images show either the temperature of the cloud tops or the surface of the Earth in cloud-free regions. The lowest temperatures (in purple) are associated with high, cold cloud tops that make up the top of the storm. In cloud-free areas the AIRS instrument will receive the infrared radiation from the surface of the Earth, resulting in the warmest temperatures (orange/red).

    Microwave Images In the AIRS microwave imagery, deep blue areas in storms show where the most precipitation occurs, or where ice crystals are present in the convective cloud tops. Outside of these storm regions, deep blue areas may also occur over the sea surface due to its low radiation emissivity. On the other hand, land appears much warmer due to its high radiation emissivity.

    Microwave radiation from Earth's surface and lower atmosphere penetrates most clouds to a greater or lesser extent depending upon their water vapor, liquid water and ice content. Precipitation, and ice crystals found at the cloud tops where strong convection is taking place, act as barriers to microwave radiation. Because of this barrier effect, the AIRS microwave sensor detects only the radiation arising at or above their location in the atmospheric column. Where these barriers are not present, the microwave sensor detects radiation arising throughout the air column and down to the surface. Liquid surfaces (oceans, lakes and rivers) have 'low emissivity' (the signal isn't as strong) and their radiation brightness temperature is therefore low. Thus the ocean also appears 'low temperature' in the AIRS microwave images and is assigned the color blue

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

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

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

  17. Communicating Storm Surge Forecast Uncertainty

    NASA Astrophysics Data System (ADS)

    Troutman, J. A.; Rhome, J.

    2015-12-01

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

  18. Risk Assessment of Hurricane Storm Surge for Tampa Bay

    NASA Astrophysics Data System (ADS)

    Lin, N.; Emanuel, K.

    2011-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  20. An early warning system for marine storm hazard mitigation

    NASA Astrophysics Data System (ADS)

    Vousdoukas, M. I.; Almeida, L. P.; Pacheco, A.; Ferreira, O.

    2012-04-01

    The present contribution presents efforts towards the development of an operational Early Warning System for storm hazard prediction and mitigation. The system consists of a calibrated nested-model train which consists of specially calibrated Wave Watch III, SWAN and XBeach models. The numerical simulations provide daily forecasts of the hydrodynamic conditions, morphological change and overtopping risk at the area of interest. The model predictions are processed by a 'translation' module which is based on site-specific Storm Impact Indicators (SIIs) (Ciavola et al., 2011, Storm impacts along European coastlines. Part 2: lessons learned from the MICORE project, Environmental Science & Policy, Vol 14), and warnings are issued when pre-defined threshold values are exceeded. For the present site the selected SIIs were (i) the maximum wave run-up height during the simulations; and (ii) the dune-foot horizontal retreat at the end of the simulations. Both SIIs and pre-defined thresholds were carefully selected on the grounds of existing experience and field data. Four risk levels were considered, each associated with an intervention approach, recommended to the responsible coastal protection authority. Regular updating of the topography/bathymetry is critical for the performance of the storm impact forecasting, especially when there are significant morphological changes. The system can be extended to other critical problems, like implications of global warming and adaptive management strategies, while the approach presently followed, from model calibration to the early warning system for storm hazard mitigation, can be applied to other sites worldwide, with minor adaptations.

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

    NASA Astrophysics Data System (ADS)

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

    2012-10-01

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

  2. Severe storm electricity

    NASA Technical Reports Server (NTRS)

    Rust, W. D.; Macgorman, D. R.; Taylor, W.; Arnold, R. T.

    1984-01-01

    Severe storms and lightning were measured with a NASA U2 and ground based facilities, both fixed base and mobile. Aspects of this program are reported. The following results are presented: (1) ground truth measurements of lightning for comparison with those obtained by the U2. These measurements include flash type identification, electric field changes, optical waveforms, and ground strike location; (2) simultaneous extremely low frequency (ELF) waveforms for cloud to ground (CG) flashes; (3) the CG strike location system (LLP) using a combination of mobile laboratory and television video data are assessed; (4) continued development of analog-to-digital conversion techniques for processing lightning data from the U2, mobile laboratory, and NSSL sensors; (5) completion of an all azimuth TV system for CG ground truth; (6) a preliminary analysis of both IC and CG lightning in a mesocyclone; and (7) the finding of a bimodal peak in altitude lightning activity in some storms in the Great Plains and on the east coast. In the forms on the Great Plains, there was a distinct class of flash what forms the upper mode of the distribution. These flashes are smaller horizontal extent, but occur more frequently than flashes in the lower mode of the distribution.

  3. A study of severe storm electricity via storm intercept

    NASA Technical Reports Server (NTRS)

    Arnold, Roy T.; Horsburgh, Steven D.; Rust, W. David; Burgess, Don

    1985-01-01

    Storm electricity data, radar data, and visual observations were used both to present a case study for a supercell thunderstorm that occurred in the Texas Panhandle on 19 June 1980 and to search for insight into how lightning to ground might be related to storm dynamics in the updraft/downdraft couplet in supercell storms. It was observed that two-thirds of the lightning ground-strike points in the developing and maturing stages of a supercell thunderstorm occurred within the region surrounding the wall cloud (a cloud feature often characteristic of a supercell updraft) and on the southern flank of the precipitation. Electrical activity in the 19 June 1980 storm was atypical in that it was a right-mover. Lightning to ground reached a peak rate of 18/min and intracloud flashes were as frequent as 176/min in the final stages of the storm's life.

  4. Laboratory measurements of wave attenuation through model and live vegetation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Surge and waves generated by hurricanes and tropical storms often cause severe damage and loss of life in coastal areas. It is widely recognized that wetlands along coastal fringes reduce storm surge and waves. Yet, the potential role and primary mechanisms of wave mitigation by wetland vegetation a...

  5. Storms on Venus: Lightning-induced chemistry and predicted products

    NASA Astrophysics Data System (ADS)

    Delitsky, M. L.; Baines, K. H.

    2015-08-01

    Observations by many spacecraft that have visited Venus over the last 40 years appear to confirm the presence of lightning storms in the Venus atmosphere. Recent observations by Venus Express indicate that lightning frequency and power is similar to that on Earth. While storms are occurring, energy deposition by lightning into Venus atmospheric constituents will immediately dissociate molecules into atoms, ions and plasma from the high temperatures in the lightning column (>30,000 K) and the associated shock waves and heating, after which these atom and ion fragments of C,O,S,N,H-containing molecules will recombine during cooldown to form new sets of molecules. Spark and discharge experiments in the literature suggest that lightning effects on the main atmospheric molecules CO2, N2, SO2, H2SO4 and H2O will yield carbon oxides and suboxides (COm, CnOm), sulfur oxides (SnO, SnOm), oxygen (O2), elemental sulfur (Sn), nitrogen oxides (NO, N2O, NO2), sulfuric acid clusters (HnSmOx-.aHnSmOx e.g. HSO4-.mH2SO4), polysulfur oxides, carbon soot and other exotic species. While the amounts generated in lightning storms would be much less than that derived from photochemistry, during storms these species can build up in a small area and so their local concentrations may increase significantly. For a storm of 100×100 km, the increase could be ~5 orders of magnitude if they remain in the storm region for a period before becoming well-mixed. Some of these molecular species may be detectable by instruments onboard Venus Express while they are concentrated in the storm regions. We explore the diversity of new products likely created in lightning storms on Venus.

  6. Response of the thermosphere and ionosphere to geomagnetic storms

    SciTech Connect

    Fuller-Rowell, T.J.; Codrescu, M.V.; Moffett, R.J.; Quegan, S.

    1994-03-01

    Four numerical simulations have been performed, at equinox, using a coupled thermosphere-ionosphere model, to illustrate the response of the upper atmosphere to geomagnetic storms. The storms are characterized by an increase in magnetospheric energy input at high latitude for a 12-hour period; each storm commences at a different universal time (UT). The initial response at high latitude is that Joule heating raises the temperature of the upper thermosphere and ion drag drives high-velocity neutral winds. The heat source drives a global wind surge, from both polar regions, which propagates to low latitudes and into the opposite hemisphere. The surge has the character of a large-scale gravity wave with a phase speed of about 600 m s{sup {minus}1}. Behind the surge a global circulation of magnitude 100 m s{sup {minus}1} is established at middle latitudes, indicating that the wave and the onset of global circulation are manifestations of the same phenomena. A dominant feature of the response is the penetration of the surge into the opposite hemisphere where it drives poleward winds for a few hours. The global wind surge has a preference for the night sector and for the longitude of the magnetic pole and therefore depends on the UT start time of the storm. A second phase of the meridional circulation develops after the wave interaction but is also restricted, in this case by the buildup of zonal winds via the Coriolis interaction. Conservation of angular momentum may limit the buildup of zonal wind in extreme cases. The divergent wind field drives upwelling and composition change on both height and pressure surfaces. The composition bulge responds to both the background and the storm-induced horizontal winds; it does not simply rotate with Earth. During the storm the disturbance wind modulates the location of the bulge; during the recovery the background winds induce a diurnal variation in its position. 39 refs., 15 figs.

  7. The Study of Insurance Premium Rate GIS Mapping Considering the Storm and Flood Hazard Risks

    NASA Astrophysics Data System (ADS)

    Lee, J. S.; Lee, I. S.

    2016-06-01

    Recently, the number of natural disaster occurrence is increasing because of abnormal changes of weather in Korea. In Korea the storm and flood insurance system is in effect to prevent these natural disasters. The national storm and flood insurance Premium rate is very low and the risk of adverse selection resides because of choosing by who lives in high risk area. To solve these problems, the storm and flood insurance rate map are required. In this study, the prototype of storm and flood insurance premium rate map of the Ulsan, Korea was made and the method of GIS analysis for the insurance premium rate calculating and the procedure of the Ulsan storm and flood insurance rate map were researched.

  8. Inside storm window

    SciTech Connect

    Kaplan, J.I.

    1980-11-01

    The work effort to design, build, install, and evaluate an inside storm window is presented. The ISW, made of two separated layers of mylar (like a thermopane window) which when not in use can be rolled up in a shade, is described. The work effort included: development of a prototype model; the development of production facilities to turn out a small number (50) of ISW's; the production of the windows; the installation of the windows into buildings; the building of a test chamber to determine the R value of the ISW and the subsequent determination of the R value; and a survey to determine how the residents of the homes in which ISW's were installed felt about the windows. Comments on each of these tasks are presented and some comments on initial steps towards commercialization are offered. (MCW)

  9. Study of Global Storm Time Energy Transport in the Lower Thermosphere using SABER Temperatures

    NASA Astrophysics Data System (ADS)

    Suresh, P.; Swenson, C.

    2013-12-01

    The SABER (Sounding of the Atmosphere using Broadband Radiation) observations represent one of the few long duration data sets of thermospheric properties between the altitude ranges of 100 to 130 km. These altitudes correspond to the region of geomagnetic storm energy deposition. The ensuing global redistribution of the geomagnetic storm energy is yet to be understood. The SABER instrument onboard the TIMED (Thermosphere Ionosphere Mesosphere Energetics and Dynamics) satellite, provides kinetic temperatures in this region of the thermosphere. We have used this temperature dataset to study the response of the lower thermosphere to geomagnetic storms. A quiet time empirical model has been formulated to isolate only the storm time response from these temperature measurements. This isolated storm time temperature response has been used as an index to study the global redistribution of the storm energy. An important result of this investigation is indications of the relative importance of gravity wave circulation vs. the meridional circulation in redistribution of the geomagnetic storm energy from the high auroral latitudes to the lower latitudes. This study encompasses various storm periods between the periods of 2002-2010. Hence this interval comprises of both the solar maximum and minimum, and also of storm periods having different intensity. As a result of having different storm intensities, we can investigate the relative effect of joule heating dominant storms vs. particle precipitation dominant storms, in this global energy redistribution. Also, the availability of data spread across a solar cycle has helped us to investigate the influence of the phase of the solar cycle in the energy redistribution and circulation following a storm period.

  10. Study of the mid-latitude ionospheric response to geomagnetic storms in the European region

    NASA Astrophysics Data System (ADS)

    Berényi, Kitti Alexandra; Barta, Veronika; Kis, Arpad

    2016-07-01

    Geomagnetic storms affect the ionospheric regions of the terrestrial upper atmosphere through different physical and atmospheric processes. The phenomena that can be regarded as a result of these processes, generally is named as "ionospheric storm". The processes depend on altitude, segment of the day, the geomagnetic latitude and longitude, strength of solar activity and the type of the geomagnetic storm. We examine the data of ground-based radio wave ionosphere sounding measurements of European ionospheric stations (mainly the data of Nagycenk Geophysical Observatory) in order to determine how and to what extent a geomagnetic disturbance of a certain strength affects the mid-latitude ionospheric regions in winter and in summer. For our analysis we used disturbed time periods between November 2012 and June 2015. Our results show significant changing of the ionospheric F2 layer parameters on strongly disturbed days compared to quiet ones. We show that the critical frequencies (foF2) increase compared to their quiet day value when the ionospheric storm was positive. On the other hand, the critical frequencies become lower, when the storm was negative. In our analysis we determined the magnitude of these changes on the chosen days. For a more complete analysis we compare also the evolution of the F2 layer parameters of the European ionosonde stations on a North-South geographic longitude during a full storm duration. The results present the evolution of an ionospheric storm over a geographic meridian. Furthermore, we compared the two type of geomagnetic storms, namely the CME caused geomagnetic storm - the so-called Sudden impulse (Si) storms- and the HSS (High Speed Solar Wind Streams) caused geomagnetic storms -the so-called Gradual storms (Gs)- impact on the ionospheric F2-layer (foF2 parameter). The results show a significant difference between the effect of Si and of the Gs storms on the ionospheric F2-layer.

  11. Untangling boulder dislodgement in storms and tsunamis: Is it possible with simple theories?

    NASA Astrophysics Data System (ADS)

    Weiss, R.; Diplas, P.

    2015-03-01

    Boulders can move during storms and tsunamis. It is difficult to find a simple method to distinguish boulders moved by tsunami waves from those moved during storms in the field. In this contribution, we explore boulder dislodgement by storm and tsunami waves by solving an adapted version of Newton's Second Law of Motion in polar coordinates and defining a critical position for boulder dislodgement. We find that the boulder dislodgement is not only a function of the causative wave, but also of the roughness in the vicinity of the boulder and the slope angle. We employ the amplitude of storm and tsunami waves to dislodge boulders of given masses to evaluate if boulder dislodgement in storms can be untangled from boulder transport in tsunamis. As the main result of our numerical experiments, we find a significant difference between storm and tsunami waves to dislodge the same boulder for large masses and large roughness values. This allows us to conclude that simple theories are applicable to answer the questions asked in the title, but we argue only if they contain a critical dislodgement condition like the one presented here.

  12. ARkStorm: A West Coast Storm Scenario

    NASA Astrophysics Data System (ADS)

    Cox, D. A.; Jones, L. M.; Ralph, F. M.; Dettinger, M. D.; Porter, K.; Perry, S. C.; Barnard, P. L.; Hoover, D.; Wills, C. J.; Stock, J. D.; Croyle, W.; Ferris, J. C.; Plumlee, G. S.; Alpers, C. N.; Miller, M.; Wein, A.; Rose, A.; Done, J.; Topping, K.

    2009-12-01

    The United Stated Geological Survey (USGS) Multi-Hazards Demonstration Project (MHDP) is preparing a new emergency-preparedness scenario, called ARkStorm, to address massive U.S. West Coast storms analogous to those that devastated California in 1861-62. Storms of this magnitude are projected to become more frequent and intense as a result of climate change. The MHDP has assembled experts from the National Oceanic and Atmospheric Administration (NOAA), USGS, Scripps Institute of Oceanography, the State of California, California Geological Survey, the University of Colorado, the National Center for Atmospheric Research, and other organizations to design the large, but scientifically plausible, hypothetical scenario storm that would provide emergency responders, resource managers, and the public a realistic assessment of what is historically possible. The ARkStorm patterns the 1861 - 1862 historical events but uses modern modeling methods and data from large storms in 1969 and 1986. The ARkStorm draws heat and moisture from the tropical Pacific, forming Atmospheric Rivers (ARs) that grow in size, gain speed, and with a ferocity equal to hurricanes, slam into the U.S. West Coast for several weeks. Using sophisticated weather models and expert analysis, precipitation, snowlines, wind, and pressure data the modelers will characterize the resulting floods, landslides, and coastal erosion and inundation. These hazards will then be translated into the infrastructural, environmental, agricultural, social, and economic impacts. Consideration will be given to catastrophic disruptions to water supplies resulting from impacts on groundwater pumping, seawater intrusion, water supply degradation, and land subsidence. Possible climate-change forces that could exacerbate the problems will also be evaluated. In contrast to the recent U.S. East and Gulf Coast hurricanes, only recently have scientific and technological advances documented the ferocity and strength of possible future

  13. Thermal Tides During the 2001 Martian Global-Scale Dust Storm

    NASA Technical Reports Server (NTRS)

    Guzewich, Scott D.; Wilson, R. John; McConnochie, Timothy H.; Toigo, Anthony D.; Bandfield, Donald J.; Smith, Michael D.

    2014-01-01

    The 2001 (Mars Year 25) global dust storm radically altered the dynamics of the Martian atmosphere. Using observations from the Thermal Emission Spectrometer onboard the Mars Global Surveyor spacecraft and Mars WRF general circulation model simulations, we examine the changes to thermal tides and planetary waves caused by the storm. We find that the extratropical diurnal migrating tide is dramatically enhanced during the storm, particularly in the southern hemisphere, reaching amplitudes of more than 20 K. The tropical diurnal migrating tide is weakened to almost undetectable levels. The diurnal Kelvin waves are also significantly weakened, particularly during the period of global expansion at Ls=200deg-210deg. In contrast, the westward propagating diurnal wavenumber 2 tide strengthens to 4-8 K at altitudes above 30km. The wavenumber 1 stationary wave reaches amplitudes of 10-12 K at 50deg-70degN, far larger than is typically seen during this time of year. The phase of this stationary wave and the enhancement of the diurnal wavenumber 2 tide appear to be responses to the high-altitude westward propagating equatorial wavenumber 1 structure in dust mixing ratio observed during the storm in previous works. This work provides a global picture of dust storm wave dynamics that reveals the coupling between the tropics and high-latitude wave responses. We conclude that the zonal distribution of thermotidal forcing from atmospheric aerosol concentration is as important to understanding the atmospheric wave response as the total global mean aerosol optical depth.

  14. Storm surge and river interaction in etuaries

    NASA Astrophysics Data System (ADS)

    Maskell, J.

    2012-04-01

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

  15. Thromboembolic complications of thyroid storm

    PubMed Central

    Min, T; Benjamin, S; Cozma, L

    2014-01-01

    Summary Thyroid storm is a rare but potentially life-threatening complication of hyperthyroidism. Early recognition and prompt treatment are essential. Atrial fibrillation can occur in up to 40% of patients with thyroid storm. Studies have shown that hyperthyroidism increases the risk of thromboembolic events. There is no consensus with regard to the initiation of anticoagulation for atrial fibrillation in severe thyrotoxicosis. Anticoagulation is not routinely initiated if the risk is low on a CHADS2 score; however, this should be considered in patients with thyroid storm or severe thyrotoxicosis with impending storm irrespective of the CHADS2 risk, as it appears to increase the risk of thromboembolic episodes. Herein, we describe a case of thyroid storm complicated by massive pulmonary embolism. Learning points Diagnosis of thyroid storm is based on clinical findings. Early recognition and prompt treatment could lead to a favourable outcome.Hypercoagulable state is a recognised complication of thyrotoxicosis.Atrial fibrillation is strongly associated with hyperthyroidism and thyroid storm.Anticoagulation should be considered for patients with severe thyrotoxicosis and atrial fibrillation irrespective of the CHADS2 score.Patients with severe thyrotoxicosis and clinical evidence of thrombosis should be immediately anticoagulated until hyperthyroidism is under control. PMID:24683480

  16. Propagation of Upper Atmospheric Storm Effects Towards Lower Latitudes

    NASA Astrophysics Data System (ADS)

    Prölss, G. W.; Očko, M.

    It has been suggested that both positive ionospheric storms at middle latitudes and anomalous increases in the neutral thermospheric density at low latitudes are caused by traveling atmospheric disturbances (TADs). Here we test this idea using ionosonde measurements and CASTOR satellite data. It is found that the major density enhancements observed during the January 10, March 26, and April 1, 1976 storm events are all preceded by ionospheric perturbations at middle latitudes. These perturbations consist of an increase in layer height followed by an increase in the ionization density. Since these are typical signatures of TADs, the present data set confirms the idea that a significant part of the upper atmosphere storm energy is transported from high to low latitudes by large-scale waves

  17. Energy Dependent Responses of Relativistic Electron Fluxes in the Outer Radiation Belt to Geomagnetic Storms

    NASA Astrophysics Data System (ADS)

    Xie, L.

    2015-12-01

    Geomagnetic storms can either increase 4 or decrease relativistic electron fluxes in the outer radiation belt. A statistical survey of 84 isolated storms demonstrates that geomagnetic storms preferentially decrease relativistic electron fluxes at higher energies while flux enhancements are more common at lower energies. In about 87% of the storms, 0.3-2.5 MeV electrons fluxes show increase, whereas 2.5-14 MeV electron fluxes increase in only 35% of the storms. Superposed epoch analyses suggest that such 'energy dependent' behavior of electrons preferably occurs during conditions of high solar wind density which is favorable to generate magnetospheric electromagnetic ion cyclotron (EMIC) waves and these 'energy dependent' events are associated with relatively weaker chorus activities. We have examined one of the cases where observed EMIC waves can resonate effectively with >2.5 MeV electrons and scatter them into the atmosphere. The correlation study further illustrates that electron flux drop-outs during storm main phases do not correlate well with the flux build-up during storm recovery phases. We suggest that a combination of efficient EMIC-induced scattering and weaker chorus-driven acceleration provide a viable candidate for the energy dependent responses of outer radiation belt relativistic electrons to geomagnetic storms. These results are of great interest to both understanding of the radiation belt dynamics and applications in space weather.

  18. Centralized Storm Information System (CSIS)

    NASA Technical Reports Server (NTRS)

    Norton, C. C.

    1985-01-01

    A final progress report is presented on the Centralized Storm Information System (CSIS). The primary purpose of the CSIS is to demonstrate and evaluate real time interactive computerized data collection, interpretation and display techniques as applied to severe weather forecasting. CSIS objectives pertaining to improved severe storm forecasting and warning systems are outlined. The positive impact that CSIS has had on the National Severe Storms Forecast Center (NSSFC) is discussed. The benefits of interactive processing systems on the forecasting ability of the NSSFC are described.

  19. Energy dependence of relativistic electron flux variations in the outer radiation belt during geomagnetic storms

    NASA Astrophysics Data System (ADS)

    Xiong, Ying; Xie, Lun; Li, Jinxing; Fu, Suiyan; Pu, Zuyin; Chen, Lunjin; Ni, Binbin; Li, Wen

    2015-04-01

    Geomagnetic storms can either increase or decrease relativistic electron fluxes in the outer radiation belt, depending on the delicate competition between electron energization and loss processes. Despite the well-known "energy independent" prototype in which electron fluxes enhance after geomagnetic storms at all energies, we present observations of "energy dependent" events, i.e., post-storm electron fluxes at lower energies (0.3-2.5 MeV, measured by MEPED/POES) recover or even exceed the pre-storm level, while electron fluxes at higher energies (2.5-14 MeV, measured by PET/SAMPEX) do not restore. The statistical survey of 84 isolated storms demonstrates that geomagnetic storms preferentially decrease relativistic electron fluxes at higher energies while flux enhancements are more common at lower energies: ~ 82% (3%) storm events produce increased (decreased) flux for 0.3-2.5 MeV electrons, while ~ 37% (45%) storms lead to enhancements (reductions) of 2.5-14 MeV electron flux. Superposed epoch analysis suggests that "energy dependent" events preferentially occur during periods of high solar wind density along with high dynamic pressure. Previous statistical studies have shown that this kind of solar wind conditions account for significant enhancements of EMIC waves, which cause efficient precipitation of > 2 MeV electrons into atmosphere via pitch angle scattering. Two cases of "energy dependent" events are investigated in detail with evident observations of EMIC waves that can resonate effectively with >2 MeV electrons. Besides, we do not capture much differences in the chorus wave activity between those "energy dependent" and "energy independent" events. Therefore, our results strongly suggest that EMIC waves play a crucial role in the occurrences of those "energy dependent" events in the outer zone during geomagnetic storms.

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

    NASA Technical Reports Server (NTRS)

    Valenti, Elizabeth; Fitzpatrick, Patrick

    2005-01-01

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

  1. The responses of artificial embayed beaches to storm events

    NASA Astrophysics Data System (ADS)

    Ojeda, E.; Guillén, J.; Ribas, F.

    2009-09-01

    The plan-view and the profile shape of sandy beaches largely depend on the incoming wave-energy (Wright and Short, 1984). In this sense, storm events are responsible for major changes in the configuration of sandy beaches and the cumulative effect of storms and fair-weather conditions determines the morphodynamic state of a certain beach. With increasing wave energy, the beach will change from the Reflective state to the Low Tide Terrace, Transverse Bar and Rip, Rhythmic Bar and Beach, Longshore Bar and Trough and finally to the Dissipative beach state. These morphodynamic states are also observed at artificial embayed beaches, although artificial groins limit alongshore sediment transport and protect sections of the beach from waves approaching from a range of directions (Short and Masselink, 1999). This contribution focuses on the morphological changes of the shoreline and the submerged sandbars of artificial embayed (sandy) beaches due to the effect of high-wave conditions associated to storms. We characterize the morphological response of the emerged and submerged beach profile of two of the artificial embayed beaches of the Barcelona city coast (NW Mediterranean). The two embayed beaches under study are single-barred beaches subject to the same climatic conditions but with different morphological characteristics. The study comprises more than 4 years of data, from November 2001 to March 2006, obtained through an Argus video system (Holman and Stanley, 2007). The extraction of the shoreline and barline locations is accomplished using 10-minute time-exposure video images. Shorelines were extracted directly from oblique images (see Ojeda and Guillén, [2008] for a complete description) and rectified afterwards. Sandbars were inferred from the rectified time-exposure video images based on the preferential wave breaking over shallow areas, so they required a minimum significant wave height (Hs) which allowed the occurrence of a clear wave-breaking pattern. The

  2. Storm-driven sediment transport in Massachusetts Bay

    NASA Astrophysics Data System (ADS)

    Warner, John C.; Butman, Bradford; Dalyander, P. Soupy

    2008-02-01

    Massachusetts Bay is a semi-enclosed embayment in the western Gulf of Maine about 50 km wide and 100 km long. Bottom sediment resuspension is controlled predominately by storm-induced surface waves and transport by the tidal- and wind-driven circulation. Because the Bay is open to the northeast, winds from the northeast ('Northeasters') generate the largest surface waves and are thus the most effective in resuspending sediments. The three-dimensional oceanographic circulation model Regional Ocean Modeling System (ROMS) is used to explore the resuspension, transport, and deposition of sediment caused by Northeasters. The model transports multiple sediment classes and tracks the evolution of a multilevel sediment bed. The surficial sediment characteristics of the bed are coupled to one of several bottom-boundary layer modules that calculate enhanced bottom roughness due to wave-current interaction. The wave field is calculated from the model Simulating WAves Nearshore (SWAN). Two idealized simulations were carried out to explore the effects of Northeasters on the transport and fate of sediments. In one simulation, an initially spatially uniform bed of mixed sediments exposed to a series of Northeasters evolved to a pattern similar to the existing surficial sediment distribution. A second set of simulations explored sediment-transport pathways caused by storms with winds from the northeast quadrant by simulating release of sediment at selected locations. Storms with winds from the north cause transport southward along the western shore of Massachusetts Bay, while storms with winds from the east and southeast drive northerly nearshore flow. The simulations show that Northeasters can effectively transport sediments from Boston Harbor and the area offshore of the harbor to the southeast into Cape Cod Bay and offshore into Stellwagen Basin. This transport pattern is consistent with Boston Harbor as the source of silver found in the surficial sediments of Cape Cod Bay and

  3. Storm-driven sediment transport in Massachusetts Bay

    USGS Publications Warehouse

    Warner, J.C.; Butman, B.; Dalyander, P.S.

    2008-01-01

    Massachusetts Bay is a semi-enclosed embayment in the western Gulf of Maine about 50 km wide and 100 km long. Bottom sediment resuspension is controlled predominately by storm-induced surface waves and transport by the tidal- and wind-driven circulation. Because the Bay is open to the northeast, winds from the northeast ('Northeasters') generate the largest surface waves and are thus the most effective in resuspending sediments. The three-dimensional oceanographic circulation model Regional Ocean Modeling System (ROMS) is used to explore the resuspension, transport, and deposition of sediment caused by Northeasters. The model transports multiple sediment classes and tracks the evolution of a multilevel sediment bed. The surficial sediment characteristics of the bed are coupled to one of several bottom-boundary layer modules that calculate enhanced bottom roughness due to wave-current interaction. The wave field is calculated from the model Simulating WAves Nearshore (SWAN). Two idealized simulations were carried out to explore the effects of Northeasters on the transport and fate of sediments. In one simulation, an initially spatially uniform bed of mixed sediments exposed to a series of Northeasters evolved to a pattern similar to the existing surficial sediment distribution. A second set of simulations explored sediment-transport pathways caused by storms with winds from the northeast quadrant by simulating release of sediment at selected locations. Storms with winds from the north cause transport southward along the western shore of Massachusetts Bay, while storms with winds from the east and southeast drive northerly nearshore flow. The simulations show that Northeasters can effectively transport sediments from Boston Harbor and the area offshore of the harbor to the southeast into Cape Cod Bay and offshore into Stellwagen Basin. This transport pattern is consistent with Boston Harbor as the source of silver found in the surficial sediments of Cape Cod Bay and

  4. Tooth - abnormal shape

    MedlinePlus

    Hutchinson incisors; Abnormal tooth shape; Peg teeth; Mulberry teeth; Conical teeth ... The appearance of normal teeth varies, especially the molars. ... conditions. Specific diseases can affect tooth shape, tooth ...

  5. Neonatal thyroid storm accompanied with severe anaemia.

    PubMed

    Cao, Lu-Ying; Wei, Hong; Wang, Zheng-Li

    2015-07-01

    Neonatal thyroid storm is rare; the diagnostic criteria and management of neonatal thyroid storm have not been well established. In this paper, we report a preterm infant diagnosed with neonatal hyperthyroidism secondary to maternal Graves' disease who was discharged after therapy. Unfortunately, he was rehospitalised for neonatal thyroid storm. We will discuss the diagnosis and general therapy of neonatal thyroid storm.

  6. The Radiation Belt Storm Probes

    NASA Video Gallery

    The Radiation Belt Storm Probe mission (RBSP) will explore the Van Allen Radiation Belts in the Earth's magnetosphere. The charge particles in these regions can be hazardous to both spacecraft and ...

  7. Cocaine Intoxication and Thyroid Storm

    PubMed Central

    Lacy, Mary E.

    2014-01-01

    Introduction. Cocaine, a widely used sympathomimetic drug, causes thermoregulatory and cardiac manifestations that can mimic a life-threatening thyroid storm. Case. A man presented to the emergency department requesting only cocaine detoxification. He reported symptoms over the last few years including weight loss and diarrhea, which he attributed to ongoing cocaine use. On presentation he had an elevated temperature of 39.4°C and a heart rate up to 130 beats per minute. Examination revealed the presence of an enlarged, nontender goiter with bilateral continuous bruits. He was found to have thyrotoxicosis by labs and was treated for thyroid storm and cocaine intoxication concurrently. The patient was ultimately diagnosed with Graves’ disease and treated with iodine-131 therapy. Conclusion. Cocaine use should be considered a possible trigger for thyroid storm. Recognition of thyroid storm is critical because of the necessity for targeted therapy and the significant mortality associated with the condition if left untreated. PMID:26425625

  8. Tropical Storm Faxai's Rainfall Rates

    NASA Video Gallery

    This animation shows Tropical Storm Faxai's rainfall rates on March 2 from a TRMM TMI/PR rainfall analysis being faded in over infrared cloud data from the TRMM VIRS instrument. Credit: SSAI/NASA, ...

  9. Cloudsat Dissects Tropical Storm Ileana

    NASA Video Gallery

    NASA's CloudSat satellite's Cloud Profiling Radar captured a sideways look across Tropical Storm Ileana on Aug. 27 at 20:40 UTC. The colors indicate intensity of reflected radar energy. The blue ar...

  10. Riding the storm out

    NASA Astrophysics Data System (ADS)

    Wurman, Josh

    2009-04-01

    I am standing on a bridge near the North Carolina coast. There is a light breeze, and I am enjoying some hazy sunshine. But this calm is an illusion: in a few minutes winds of up to 45ms-1 (100 mph) will sweep in again. The approaches to my section of the bridge are already drowned under 2.5 m of water, and my companions on this island are an eclectic mix of traumatized animals, including snakes, rats, wounded pelicans and frogs. Earlier, one of the snakes flew through the air past my truck. The animals and I have been drawn to this bridge by Hurricane Isabel, which has just slammed into the coastal islands of North Carolina, and at the moment we are in the calm, sunny eye of the storm. The animals are just trying to survive on the area's only dry ground. But I have come to the bridge with a radar system on a truck and have spent a night and a day on it because I want to know what is happening inside this hurricane.

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

    PubMed Central

    Drews, Carl

    2013-01-01

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

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

    PubMed

    Drews, Carl

    2013-01-01

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

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

    PubMed

    Drews, Carl

    2013-01-01

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

  14. On Adler space-time extremes during ocean storms

    NASA Astrophysics Data System (ADS)

    Romolo, Alessandra; Arena, Felice

    2015-04-01

    The paper concerns the statistical properties of extreme ocean waves in the space-time domain. In this regard, a solution for the exceedance probability of the maximum crest height during a sea state over a certain area is obtained. The approach is based on the Adler's solution for the extremal probability for Gaussian random processes in a multidimensional domain. The method is able to include the effects of spatial variability of three-dimensional sea waves on short-term prediction, both over an assigned area XY and in a given direction. Next, the storm-term predictions in the space-time are investigated. For this purpose, the exceedance probability of ηmaxfunc during an ocean storm over an assigned area A is derived. This solution gives a generalization to the space-time of the Borgman's time-based model for nonstationary processes. The validity of the model is assessed from wave data of two buoys of the NOOA-NDBC network located along the Pacific and the Atlantic U.S. coasts. The results show that the size of the spatial domain A remarkably influences the expected maximum crest height during a sea storm. Indeed, the exceedance probabilities of the maximum crest height during an ocean storm over a certain area significantly deviate from the classical Borgman's model in time for increasing area. Then, to account for the nonlinear contributions on crest height, the proposed model is exploited jointly with the Forristall's distribution for nonlinear crest amplitudes in a given sea state. Finally, Monte Carlo simulations of a sea storm are performed showing a very good agreement with theoretical results.

  15. Ionospheric redistribution during geomagnetic storms

    PubMed Central

    Immel, T J; Mannucci, A J

    2013-01-01

    [1]The abundance of plasma in the daytime ionosphere is often seen to grow greatly during geomagnetic storms. Recent reports suggest that the magnitude of the plasma density enhancement depends on the UT of storm onset. This possibility is investigated over a 7year period using global maps of ionospheric total electron content (TEC) produced at the Jet Propulsion Laboratory. The analysis confirms that the American sector exhibits, on average, larger storm time enhancement in ionospheric plasma content, up to 50% in the afternoon middle-latitude region and 30% in the vicinity of the high-latitude auroral cusp, with largest effect in the Southern Hemisphere. We investigate whether this effect is related to the magnitude of the causative magnetic storms. Using the same advanced Dst index employed to sort the TEC maps into quiet and active (Dst<−100 nT) sets, we find variation in storm strength that corresponds closely to the TEC variation but follows it by 3–6h. For this and other reasons detailed in this report, we conclude that the UT-dependent peak in storm time TEC is likely not related to the magnitude of external storm time forcing but more likely attributable to phenomena such as the low magnetic field in the South American region. The large Dst variation suggests a possible system-level effect of the observed variation in ionospheric storm response on the measured strength of the terrestrial ring current, possibly connected through UT-dependent modulation of ion outflow. PMID:26167429

  16. Magnetic storms and induction hazards

    USGS Publications Warehouse

    Love, Jeffrey J.; Rigler, E. Joshua; Pulkkinen, Antti; Balch, Christopher

    2014-01-01

    Magnetic storms are potentially hazardous to the activities and technological infrastructure of modern civilization. This reality was dramatically demonstrated during the great magnetic storm of March 1989, when surface geoelectric fields, produced by the interaction of the time-varying geomagnetic field with the Earth's electrically conducting interior, coupled onto the overlying Hydro-Québec electric power grid in Canada. Protective relays were tripped, the grid collapsed, and about 9 million people were temporarily left without electricity [Bolduc, 2002].

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

    NASA Astrophysics Data System (ADS)

    Deb, Mithun; Ferreira, Celso; Lawler, Seth

    2014-05-01

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

  18. A case study of ionospheric storm effects in the Chinese sector during the October 2013 geomagnetic storm

    NASA Astrophysics Data System (ADS)

    Mao, Tian; Sun, Lingfeng; Hu, Lianhuan; Wang, Yungang; Wang, Zhijun

    2015-11-01

    In this study, we investigate the ionospheric storm effects in the Chinese sector during 2 October 2013 geomagnetic storm. The TEC map over China sector (1° × 1°) and eight ionosondes data along the longitude of 110°E are used to show significant positive ionospheric phases (enhancements in TEC and ionospheric peak electron density NmF2) in the high-middle latitude region and the negative effects at the low latitude and equatorial region during the storm. A wave structure with periods about 1-2 h and horizontal speed about 680 m/s, propagating from the high latitudes to the low latitudes is observed in electron densities within the height region from 200 to 400 km, which is caused by the combined effects of neutral wind and the large-scale traveling disturbances (LSTIDs). In the low latitude regions, compared with those in the quiet day, the ionospheric peak heights of the F2 layer (hmF2) in the storm day obviously increase accompanying a notably decrease in TEC and NmF2, which might be as a result of the eastward prompt penetration electric field (PPEF) evidenced by the two magnetometers and the subsequent westward disturbance dynamo electric fields (DDEF). The storm-time TEC enhancement mainly occurs in the topside ionosphere, as revealed from the topside TEC, bottomside TEC and GPS TEC.

  19. Forecasting the impact of storm waves and sea-level rise on Midway Atoll and Laysan Island within the Papahānaumokuākea Marine National Monument—a comparison of passive versus dynamic inundation models

    USGS Publications Warehouse

    Storlazzi, Curt D.; Berkowitz, Paul; Reynolds, Michelle H.; Logan, Joshua B.

    2013-01-01

    Two inundation events in 2011 underscored the potential for elevated water levels to damage infrastructure and affect terrestrial ecosystems on the low-lying Northwestern Hawaiian Islands in the Papahānaumokuākea Marine National Monument. The goal of this study was to compare passive "bathtub" inundation models based on geographic information systems (GIS) to those that include dynamic water levels caused by wave-induced set-up and run-up for two end-member island morphologies: Midway, a classic atoll with islands on the shallow (2-8 m) atoll rim and a deep, central lagoon; and Laysan, which is characterized by a deep (20-30 m) atoll rim and an island at the center of the atoll. Vulnerability to elevated water levels was assessed using hindcast wind and wave data to drive coupled physics-based numerical wave, current, and water-level models for the atolls. The resulting model data were then used to compute run-up elevations using a parametric run-up equation under both present conditions and future sea-level-rise scenarios. In both geomorphologies, wave heights and wavelengths adjacent to the island shorelines increased more than three times and four times, respectively, with increasing values of sea-level rise, as more deep-water wave energy could propagate over the atoll rim and larger wind-driven waves could develop on the atoll. Although these increases in water depth resulted in decreased set-up along the islands’ shorelines, the larger wave heights and longer wavelengths due to sea-level rise increased the resulting wave-induced run-up. Run-up values were spatially heterogeneous and dependent on the direction of incident wave direction, bathymetry, and island configuration. Island inundation was modeled to increase substantially when wave-driven effects were included, suggesting that inundation and impacts to infrastructure and terrestrial habitats will occur at lower values of predicted sea-level rise, and thus sooner in the 21st century, than suggested

  20. Structurally abnormal human autosomes

    SciTech Connect

    1993-12-31

    Chapter 25, discusses structurally abnormal human autosomes. This discussion includes: structurally abnormal chromosomes, chromosomal polymorphisms, pericentric inversions, paracentric inversions, deletions or partial monosomies, cri du chat (cat cry) syndrome, ring chromosomes, insertions, duplication or pure partial trisomy and mosaicism. 71 refs., 8 figs.

  1. Temperature changes over storms from measurements of spacecraft TIMED

    NASA Astrophysics Data System (ADS)

    Pylypenko, S. Motsyk, O.; Kozak, L.

    2016-09-01

    In the present work we have studied changes of mesospheric temperature over the powerful storms Wilma, Haitang, and Katrina using measurements of the space vehicle TIMED. We have found the temperature increasing at the altitude range 80-100 km. We have found the explanations for the obtained results by the dissipation of the gravity waves. Propagation of atmospheric gravity waves in a non-isothermal, windless atmosphere, with taking into account the viscosity and the thermal conductivity, has also been modelled in this work. We have determined that the maximum of amplitude of the atmospheric-gravity waves at the considered characteristics corresponds to altitudes of near 90 km (mesopause). It was found that the main factor influencing propagation and dissipation of the wave in such cases is the vertical temperature gradient. Viscosity and thermal conductivity have less influence on the wave amplitude.

  2. Morphological abnormalities among lampreys

    USGS Publications Warehouse

    Manion, Patrick J.

    1967-01-01

    The experimental control of the sea lamprey (Petromyzon marinus) in the Great Lakes has required the collection of thousands of lampreys. Representatives of each life stage of the four species of the Lake Superior basin were examined for structural abnormalities. The most common aberration was the presence of additional tails. The accessory tails were always postanal and smaller than the normal tail. The point of origin varied; the extra tails occurred on dorsal, ventral, or lateral surfaces. Some of the extra tails were misshaped and curled, but others were normal in shape and pigment pattern. Other abnormalities in larval sea lampreys were malformed or twisted tails and bodies. The cause of the structural abnormalities is unknown. The presence of extra caudal fins could be genetically controlled, or be due to partial amputation or injury followed by abnormal regeneration. Few if any lampreys with structural abnormalities live to sexual maturity.

  3. Current understanding of magnetic storms: Storm-substorm relationships

    SciTech Connect

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

    1998-08-01

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

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

    USGS Publications Warehouse

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

    2015-01-01

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

  5. Upstream influence of numerically simulated squall-line storms

    NASA Astrophysics Data System (ADS)

    Fovell, Robert G.

    2002-04-01

    The squall line's impact on its upstream environment is examined using traditional cloud and simplified (parametrized moisture) models. The study was motivated by the need to explain significant differences between the two dynamical frameworks. In both, the first environmental response to the convection consists of a rapidly propagating gravity wave characterized by deep tropospheric subsidence. This gravity wave accelerates the lowlevel storm inflow in its wake, with the largest effect seen near the surface. In the more sophisticated model, however, this wave is eventually followed by a shorter vertical wavelength feature, one possessing lower-tropospheric ascent. This second gravity wave, absent from the simplified model runs, substantially alters the upstream environment yet again. The gentle low-level uplift establishes the 'cool/moist tongue' ofairthat has been found to stretch well ahead of the storm in simulations. Between the second wave and the main storm updraught, the accelerated inflow is shifted from the ground to the middle troposphere where it helps to push dry air into the convecting region. This subsequent environmental adjustment responds to the establishment of a small yet persistent area of weak cooling during the early mature phase. Located in the middle troposphere at the upstream edge of the main cloud mass, this cooling is the combined effect of cloud-water evaporation and the ascent of subsaturated air. Though the cooling that excites it is of relatively small magnitude (<2 K), this wave's effect is dramatic and significant. A crude fix to the moisture parametrization served to establish a qualitatively similar tongue-like feature in the simplified model simulations, bringing the results from the two dynamical frameworks more into line.

  6. Abnormal uterine bleeding.

    PubMed

    Jennings, J C

    1995-11-01

    Physicians who care for female patients cannot avoid the frequent complaint of abnormal uterine bleeding. Knowledge of the disorders that cause this problem can prevent serious consequences in many patients and improve the quality of life for many others. The availability of noninvasive and minimally invasive diagnostic studies and minimally invasive surgical treatment has revolutionized management of abnormal uterine bleeding. Similar to any other disorder, the extent to which a physician manages abnormal uterine bleeding depends on his or her own level of comfort. When limitations of either diagnostic or therapeutic capability are encountered, consultation and referral should be used to the best interest of patients.

  7. Storm tracks near marginal stability

    NASA Astrophysics Data System (ADS)

    Ambaum, Maarten; Novak, Lenka

    2015-04-01

    The variance of atmospheric storm tracks is characterised by intermittent bursts of activity interspersed with relatively quiescent periods. Most of the poleward heat transport by storm tracks is due to a limited number of strong heat flux events, which occur in a quasi-periodic fashion. This behaviour is in contradiction with the usual conceptual model of the storm tracks, which relies on high growth rate background flows which then spawn weather systems that grow in an exponential or non-normal fashion. Here we present a different conceptual model of the atmospheric storm tracks which is built on the observation that, when including diabatic and other dissipative effects, the storm track region is in fact most of the time marginally stable. The ensuing model is a nonlinear oscillator, very similar to Volterra-Lotka predator-prey models. We demonstrate the extensions of this model to a stochastically driven nonlinear oscillator. The model produces quasi-periodic behaviour dominated by intermittent heat flux events. Perhaps most surprisingly, we will show strong evidence from re-analysis data for our conceptual model: the re-analysis data produces a phase-space plot that is very similar indeed to the phase-space plot for our nonlinear oscillator model.

  8. Tropical Storms Bud and Dera

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Like dancers pirouetting in opposite directions, the rotational patterns of two different tropical storms are contrasted in this pair of Multi-angle Imaging Spectroradiometer (MISR) nadir-camera images. The left-hand image is of Tropical Storm Bud, acquired on June 17, 2000 (Terra orbit 2656) as the storm was dissipating. Bud was situated in the eastern Pacific Ocean between Socorro Island and the southern tip of Baja California. South of the storm's center is a vortex pattern caused by obstruction of the prevailing flow by tiny Socorro Island. Sonora, Mexico and Baja California are visible at the top of the image. The right-hand image is of Tropical Cyclone Dera, acquired on March 12, 2001. Dera was located in the Indian Ocean, south of Madagascar. The southern end of this large island is visible in the top portion of this image. Northern hemisphere tropical storms, like Bud, rotate in a counterclockwise direction, whereas those in the southern hemisphere, such as Dera, rotate clockwise. The opposite spins are a consequence of Earth's rotation. Each image covers a swath approximately 380 kilometers wide. Image courtesy NASA/JPL/GSFC/LaRC, MISR Team

  9. Tropical Storms Bud and Dera

    NASA Technical Reports Server (NTRS)

    2001-01-01

    Like dancers pirouetting in opposite directions, the rotational patterns of two different tropical storms are contrasted in this pair of MISR nadir-camera images.

    The left-hand image is of Tropical Storm Bud, acquired on June 17, 2000 (Terra orbit 2656) as the storm was dissipating. Bud was situated in the eastern Pacific Ocean between Socorro Island and the southern tip of Baja California. South of the storm's center is a vortex pattern caused by obstruction of the prevailing flow by tiny Socorro Island. Sonora, Mexico and Baja California are visible at the top of the image.

    The right-hand image is of Tropical Cyclone Dera, acquired on March 12, 2001 (Terra orbit 6552). Dera was located in the Indian Ocean, south of Madagascar. The southern end of this large island is visible in the top portion of this image.

    Northern hemisphere tropical storms, like Bud, rotate in a counterclockwise direction, whereas those in the southern hemisphere, such as Dera, rotate clockwise. The opposite spins are a consequence of Earth's rotation.

    Each image covers a swath approximately 380 kilometers wide.

    MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.

  10. Experimental investigation of wave attenuation through model and live vegetation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hurricanes and tropical storms often cause severe damage and loss of life in coastal areas. It is widely recognized that wetlands along coastal fringes reduce storm surge and waves. Yet, the potential role and primary mechanisms of wave mitigation by wetland vegetation are not fully understood. K...

  11. Generation of traveling atmospheric disturbances during pulsating geomagnetic storms

    NASA Astrophysics Data System (ADS)

    Gardner, Larry; Schunk, Robert

    Traveling Atmospheric Disturbances (TADs) are effective in transporting momentum and en-ergy deposited at high latitudes to the mid and low latitude regions of the thermosphere. They also act to transport momentum and energy from the lower thermosphere into the upper ther-mosphere. Previously, model studies have been conducted to determine the characteristics of isolated, single-pulse TADs, but the generation of multiple TADs excited during pulsating storms have not been considered before. Here, a high-resolution global thermosphere-ionosphere model was used to study the basic characteristic of multiple TADs excited during pulsating storms, including idealized weak and strong pulsating storms, and an approximation of the May 4, 1998 pulsating storm. For all three pulsating storm simulations, multiple TADs were excited that propagated away form the auroral oval both toward the poles and toward the equator at all longitudes, with the maximum amplitudes between midnight and dawn. The TAD amplitudes were a maximum near the poles, diminished towards the equator and were larger on the nightside than on the dayside. The TADs propagated at a slight upward angle to the horizontal, with the result that the lower boundary of the TADs increased with decreas-ing latitude. The TADs crossed the equator and propagated to mid-latitudes in the opposite hemisphere, where wave interference occurred for the strong pulsating storm cases. The TAD wavelengths vary from 2500-3000 km and the phase speeds from 800-1000 m/s. The maximum TAD perturbations are 20% for the mass density 14% for the neutral temperature and 100 m/s for the winds.

  12. Generation of traveling atmospheric disturbances during pulsating geomagnetic storms

    NASA Astrophysics Data System (ADS)

    Gardner, L. C.; Schunk, R. W.

    2010-08-01

    Traveling atmospheric disturbances (TADs) are effective in transporting momentum and energy deposited at high latitudes to the midlatitude and low-latitude regions of the thermosphere. They also act to transport momentum and energy from the lower thermosphere into the upper thermosphere. Previously, model studies have been conducted to determine the characteristics of isolated, single-pulse TADs, but the generation of multiple TADs excited during pulsating storms have not been considered before. Here a high-resolution global thermosphere-ionosphere model was used to study the basic characteristics of multiple TADs excited during pulsating storms, including idealized weak and strong pulsating storms, and an approximation of the 4 May 1998 pulsating storm. For all three pulsating storm simulations, multiple TADs that propagated away from the auroral oval toward both the poles and the equator at all longitudes, with the maximum amplitudes between midnight and dawn, were excited. The TAD amplitudes were at maximum near the poles and diminished toward the equator and were larger on the nightside than on the dayside. The TADs propagated at a slightly upward angle to the horizontal, with the result that the lower boundary of the TADs increased with decreasing latitude. The TADs crossed the equator and propagated to midlatitudes in the opposite hemisphere, where wave interference occurred for the strong pulsating storm cases. The TAD wavelengths vary from 2500 to 3000 km and the phase speeds vary from 800 to 1000 m/s. The maximum TAD perturbations are 20% for the mass density, 14% for the neutral temperature, and 100 m/s for the winds.

  13. Arecibo observations of ionospheric perturbations associated with the passage of Tropical Storm Odette

    NASA Astrophysics Data System (ADS)

    Bishop, R. L.; Aponte, N.; Earle, G. D.; Sulzer, M.; Larsen, M. F.; Peng, G. S.

    2006-11-01

    A suite of instruments including incoherent scatter radar, ionosonde, and a satellite-bourne GPS receiver observed the ionosphere immediately following the passage of a tropical storm. Tropical Storm Odette formed on 4 December 2003 and proceeded northeasterly over the next 4 days, passing within 600 km of the Arecibo Observatory (AO). On the night of 7-8 December AO measured F region plasma densities and velocities nearly coincident with the storm. Large velocity variations, 10-80 m/s, are evident in the plasma drift components. The variations appear wave-like with an average period of 90 min at 367 km. Zonal drifts were observed with magnitudes significantly greater than commonly observed for similar geomagnetic conditions. The Ramey ionosonde observed intense midlatitude spread F on the night following the closest passage of the storm. GPS occultations within the storm path showed an increase in gravity wave activity and F region scintillation. Combining the local increase in gravity wave activity with the large drift variations and dominant meridional electric field observed immediately following the storm's traversal of the flux tube coincident with the AO observing volume provide insight into coupling between mesoscale weather systems and the ionosphere.

  14. "Jeopardy" in Abnormal Psychology.

    ERIC Educational Resources Information Center

    Keutzer, Carolin S.

    1993-01-01

    Describes the use of the board game, Jeopardy, in a college level abnormal psychology course. Finds increased student interaction and improved application of information. Reports generally favorable student evaluation of the technique. (CFR)

  15. Abnormal Uterine Bleeding

    MedlinePlus

    ... Abnormal uterine bleeding is any bleeding from the uterus (through your vagina) other than your normal monthly ... or fibroids (small and large growths) in the uterus can also cause bleeding. Rarely, a thyroid problem, ...

  16. Abnormal Uterine Bleeding FAQ

    MedlinePlus

    ... as cancer of the uterus, cervix, or vagina • Polycystic ovary syndrome How is abnormal bleeding diagnosed? Your health care ... before the fetus can survive outside the uterus. Polycystic Ovary Syndrome: A condition characterized by two of the following ...

  17. Bracing for the geomagnetic storms

    SciTech Connect

    Kappenman, J.G. ); Albertson, V.D. )

    1990-03-01

    The authors discuss the impact of geomagnetic storms on utility transmission networks. The effects of a recent storm on the Hydro-Quebec transmission system are described in detail. Research into geomagnetic disturbance prediction is discussed. In coming months, geomagnetic field activity will be high as it builds toward a peak, the 22nd since reliable records of the phenomenon began in the mid-1700s. The peaks come in roughly 11-year cycles, and the next is expected later this year or early in 1991. The solar activity has so far risen at one of the fastest rates ever recorded, and solar forecasters expect cycle 22 to have unusually high activity levels.

  18. National Severe Storms Forecast Center

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The principal mission of the National Severe Storms Forecast Center (NSSFC) is to maintain a continuous watch of weather developments that are capable of producing severe local storms, including tornadoes, and to prepare and issue messages designated as either Weather Outlooks or Tornado or Severe Thunderstorm Watches for dissemination to the public and aviation services. In addition to its assigned responsibility at the national level, the NSSFC is involved in a number of programs at the regional and local levels. Subsequent subsections and paragraphs describe the NSSFC, its users, inputs, outputs, interfaces, capabilities, workload, problem areas, and future plans in more detail.

  19. GPM Sees Powerful Storms in Tropical Storm Hermine

    NASA Video Gallery

    This is a 3-D animated flyby of Tropical Storm Hermine created using radar data from the GPM core satellite. On Aug. 31 at 4 p.m. EDT GPM found rainfall occurring at a rate of over 9.9 inches (251 ...

  20. Teleseismic S wave microseisms

    NASA Astrophysics Data System (ADS)

    Nishida, Kiwamu; Takagi, Ryota

    2016-08-01

    Although observations of microseisms excited by ocean swells were firmly established in the 1940s, the source locations remain difficult to track. Delineation of the source locations and energy partition of the seismic wave components are key to understanding the excitation mechanisms. Using a seismic array in Japan, we observed both P and S wave microseisms excited by a severe distant storm in the Atlantic Ocean. Although nonlinear forcing of an ocean swell with a one-dimensional Earth model can explain P waves and vertically polarized S waves (SV waves), it cannot explain horizontally polarized S waves (SH waves). The precise source locations may provide a new catalog for exploring Earth’s interior.

  1. Teleseismic S wave microseisms.

    PubMed

    Nishida, Kiwamu; Takagi, Ryota

    2016-08-26

    Although observations of microseisms excited by ocean swells were firmly established in the 1940s, the source locations remain difficult to track. Delineation of the source locations and energy partition of the seismic wave components are key to understanding the excitation mechanisms. Using a seismic array in Japan, we observed both P and S wave microseisms excited by a severe distant storm in the Atlantic Ocean. Although nonlinear forcing of an ocean swell with a one-dimensional Earth model can explain P waves and vertically polarized S waves (SV waves), it cannot explain horizontally polarized S waves (SH waves). The precise source locations may provide a new catalog for exploring Earth's interior. PMID:27563094

  2. Templates of Change: Storms and Shoreline Hazards.

    ERIC Educational Resources Information Center

    Dolan, Robert; Hayden, Bruce

    1980-01-01

    Presents results of research designed to assess and predict the storm-related hazards of living on the coast. Findings suggest that certain sections of coastline are more vulnerable than others to storm damage. (WB)

  3. Tropical Storm Debby Moves into Atlantic

    NASA Video Gallery

    An animation of satellite observations shows the progression of Tropical Storm Debby from June 25-27, 2012. The animation shows that Tropical Storm Debby's center move from the northeastern Gulf of...

  4. Satellite View of 2 Trop. Storms

    NASA Video Gallery

    System 98L exploded into Tropical Storm Irene on Saturday, August 20. This GOES-13 Video shows Tropical Storm Harvey making landfall in Belize (just beneath the Yucatan Peninsula) and moving into t...

  5. Storm Surge Climatology of the Arctic Marginal Seas

    NASA Astrophysics Data System (ADS)

    Proshutinsky, T.; Proshutinsky, A.; Maslanik, J.; Solomon, S.; Ashik, I.

    2002-12-01

    The shore of the arctic seas are generally of low relief and the combination of waves and high water levels during late summer and fall storms before the development of significant sea-ice cover can be particularly damaging to shorelines. Gravel barrier beaches can be overwashed and eroded while bluffs consisting of unlithified ice-bonded sediment and segregated ice can fail and retreat. Storm surge climatology of the arctic marginal seas is investigated based on observational data and 2-D coupled ice-ocean barotropic model results. Meteorological forcing is calculated based on NCAR/NCEP reanalysis data for 1948-present period. The spatial resolution of the model is 13.89 km. The sea ice conditions (concentration and thickness) are prescribed on the mean monthly basis. The model was calibrated based on the strongest storm surges observed in the Kara, Laptev, East-Siberian, Chukchi and Beaufort Seas. Simulation results are in relatively good agreement with observations of sea level heights and ice drift. Detailed studies showed that the spatial and temporal resolutions of the NCEP/NCAR sea level pressure data (2.5x2.5 degree, 6 hours) are too low and can not reproduce well extreme conditions typical for the relatively small polar cyclones but storm surge event frequency is reproduce very well. The results of this study can be used to aid current and future scenario risk assessments of coastal flooding and costal erosion rates.

  6. Intensification of Pacific storm track linked to Asian pollution.

    PubMed

    Zhang, Renyi; Li, Guohui; Fan, Jiwen; Wu, Dong L; Molina, Mario J

    2007-03-27

    Indirect radiative forcing of atmospheric aerosols by modification of cloud processes poses the largest uncertainty in climate prediction. We show here a trend of increasing deep convective clouds over the Pacific Ocean in winter from long-term satellite cloud measurements (1984-2005). Simulations with a cloud-resolving weather research and forecast model reveal that the increased deep convective clouds are reproduced when accounting for the aerosol effect from the Asian pollution outflow, which leads to large-scale enhanced convection and precipitation and hence an intensified storm track over the Pacific. We suggest that the wintertime Pacific is highly vulnerable to the aerosol-cloud interaction because of favorable cloud dynamical and microphysical conditions from the coupling between the Pacific storm track and Asian pollution outflow. The intensified Pacific storm track is climatically significant and represents possibly the first detected climate signal of the aerosol-cloud interaction associated with anthropogenic pollution. In addition to radiative forcing on climate, intensification of the Pacific storm track likely impacts the global general circulation due to its fundamental role in meridional heat transport and forcing of stationary waves.

  7. Attribution of storm surge events in the Baltic Sea

    NASA Astrophysics Data System (ADS)

    Klehmet, Katharina; Burkhardt, Rockel

    2016-04-01

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

  8. Simulating the effects of vegetation on storm surge and coastal inundation

    NASA Astrophysics Data System (ADS)

    Lapetina, A. J.; Sheng, Y.

    2012-12-01

    Vegetation such as tidal marshes and mangroves can significantly affect coastal hydrodynamics, including water levels, wave processes, turbulent mixing, storm surge, and coastal inundation. This study makes use of a one dimensional turbulent kinetic energy (TKE) model developed by Sheng, et al. [2012] and validated with data from several flume experiments, including those of Shimizu and Tsujimoto [1994], Nepf and Vivoni [2000], and Neumeier [2007]. This one dimensional vertical model is unique because it evaluates profile drag and skin friction drag introduced by vegetation separately. The model is incorporated into a three-dimensional coupled circulation-wave model, CH3D-SWAN, to simulate the influence of coastal wetlands on storm surge and inundation at the regional scale. In many two-dimensional storm surge models, the effects of vegetation are included through an enhanced Manning coefficient, but the modeling system presented here is a significant improvement, because it realistically models vertical velocity profiles in flow through vegetation. Two experiments utilizing this three-dimensional vegetation-resolving storm surge model are presented, one investigating the influence of vegetation canopies of varying sizes on the same storm, and another examining how the dissipation of storm surge by given vegetation is affected by a storm's forward speed and intensity. Three variables describing vegetation canopies are considered (canopy density, canopy height, canopy width) and two variables describing storm conditions are considered (forward speed and storm intensity). Clear trends on the influence of various parameters emerge, and will prove valuable to coastal scientists, engineers, land-use planners, and ecologists.

  9. Discontinuous Galerkin methods for modeling Hurricane storm surge

    NASA Astrophysics Data System (ADS)

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

    2011-09-01

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

  10. ENSO and winter storms in California

    USGS Publications Warehouse

    Cayan, D.R.; Bromirski, Peter

    2003-01-01

    The frequency and intensity of North Pacific winter storms that penetrate the California coast drives the winds, sea level, precipitation and streamflow that are crucial influences on coastal processes. There is considerable variability of these storm characteristics, in large part owing to the El Nino/Southern Oscillation (ENSO} phenomenon. There is a great contrast of the storm characteristics during the El Nino phase vs. the La Nina phase, with the largest scale, southerly extensive winter storms generated during El Nino.

  11. Thyroid storm during beta blockade.

    PubMed

    Strube, P J

    1984-04-01

    A thyrotoxic patient who had received beta-adrenoceptor blockers pre-operatively suffered an episode of severe heart failure immediately following thyroidectomy and required artificial ventilation of the lungs for six hours. The possible causes are discussed and the likelihood of thyroid storm unmitigated by beta adrenergic blockade suggested.

  12. Storm Water Management Model (SWMM)

    EPA Science Inventory

    Stormwater discharges continue to cause impairment of our Nation’s waterbodies. Regulations that require the retention and/or treatment of frequent, small storms that dominate runoff volumes and pollutant loads are becoming more common. The U.S. Environmental Protection Agency (E...

  13. Rain from Tropical Storm Noel

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Though not the most powerful storm of the 2007 Atlantic Hurricane season, Tropical Storm Noel was among the most deadly. Only Category 5 Hurricane Felix and its associated flooding had a higher toll. The slow-moving Tropical Storm Noel inundated the Dominican Republic, Haiti, Jamaica, Cuba, and the Bahamas with heavy rain between October 28 and November 1, 2007. The resulting floods and mudslides left at least 115 dead and thousands homeless throughout the Caribbean, reported the Associated Press on November 2, 2007. This image shows the distribution of the rainfall that made Noel a deadly storm. The image shows rainfall totals as measured by the Multi-satellite Precipitation Analysis (MPA) at NASA Goddard Space Flight Center from October 26 through November 1, 2007. The analysis is based on measurements taken by the Tropical Rainfall Measuring Mission (TRMM) satellite. The heaviest rainfall fell in the Dominican Republic and the Bahamas, northeast of Noel's center. Areas of dark red show that rainfall totals over the south-central Dominican Republic and parts of the Bahamas were over 551 millimeters (21 inches). Much of eastern Hispaniola, including both the Dominican Republic and Haiti received at least 200 mm (about 8 inches) of rain, shown in yellow. Rainfall totals over Haiti and Cuba were less, with a range of at least 50 mm (2 inches) to over 200 mm (8 inches).

  14. Storm Water Management Model (SWMM)

    EPA Science Inventory

    Stormwater discharges continue to cause impairment of our Nation’s waterbodies. Regulations that require the retention and/or treatment of frequent, small storms that dominate runoff volumes and pollutant loads are becoming more common. The U.S. Environmental Protection Age...

  15. Characterizing Times Between Storms in Mountainous Areas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An exploratory investigation was conducted on how two parameters that characterize dry times between storms (average time between storms, ATBS, and minimum dry time between storms, MTBS) vary with elevation, and how these two parameters may be estimated for areas without data. 16 rain gauges with h...

  16. 46 CFR 177.920 - Storm rails.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Storm rails. 177.920 Section 177.920 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS (UNDER 100 GROSS TONS) CONSTRUCTION AND ARRANGEMENT Rails and Guards § 177.920 Storm rails. Suitable storm rails or hand grabs must...

  17. 46 CFR 116.920 - Storm rails.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Storm rails. 116.920 Section 116.920 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS CARRYING MORE THAN 150... and Guards § 116.920 Storm rails. Suitable storm rails or hand grabs must be installed where...

  18. 46 CFR 116.920 - Storm rails.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Storm rails. 116.920 Section 116.920 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS CARRYING MORE THAN 150... and Guards § 116.920 Storm rails. Suitable storm rails or hand grabs must be installed where...

  19. 46 CFR 169.329 - Storm rails.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Storm rails. 169.329 Section 169.329 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Construction and Arrangement Rails and Guards § 169.329 Storm rails. Suitable storm rails or hand grabs must...

  20. 46 CFR 169.329 - Storm rails.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Storm rails. 169.329 Section 169.329 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Construction and Arrangement Rails and Guards § 169.329 Storm rails. Suitable storm rails or hand grabs must...

  1. 46 CFR 127.320 - Storm rails.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Storm rails. 127.320 Section 127.320 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS CONSTRUCTION AND ARRANGEMENTS Rails and Guards § 127.320 Storm rails. Suitable storm rails must be installed in each passageway and...

  2. 46 CFR 177.920 - Storm rails.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Storm rails. 177.920 Section 177.920 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS (UNDER 100 GROSS TONS) CONSTRUCTION AND ARRANGEMENT Rails and Guards § 177.920 Storm rails. Suitable storm rails or hand grabs must...

  3. 46 CFR 169.329 - Storm rails.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Storm rails. 169.329 Section 169.329 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Construction and Arrangement Rails and Guards § 169.329 Storm rails. Suitable storm rails or hand grabs must...

  4. 46 CFR 116.920 - Storm rails.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Storm rails. 116.920 Section 116.920 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS CARRYING MORE THAN 150... and Guards § 116.920 Storm rails. Suitable storm rails or hand grabs must be installed where...

  5. 46 CFR 127.320 - Storm rails.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Storm rails. 127.320 Section 127.320 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS CONSTRUCTION AND ARRANGEMENTS Rails and Guards § 127.320 Storm rails. Suitable storm rails must be installed in each passageway and...

  6. 46 CFR 127.320 - Storm rails.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Storm rails. 127.320 Section 127.320 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS CONSTRUCTION AND ARRANGEMENTS Rails and Guards § 127.320 Storm rails. Suitable storm rails must be installed in each passageway and...

  7. 46 CFR 108.221 - Storm rails.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Storm rails. 108.221 Section 108.221 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Rails § 108.221 Storm rails. Each unit must have a storm rail in the...

  8. 46 CFR 108.221 - Storm rails.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Storm rails. 108.221 Section 108.221 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Rails § 108.221 Storm rails. Each unit must have a storm rail in the...

  9. 46 CFR 177.920 - Storm rails.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Storm rails. 177.920 Section 177.920 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS (UNDER 100 GROSS TONS) CONSTRUCTION AND ARRANGEMENT Rails and Guards § 177.920 Storm rails. Suitable storm rails or hand grabs must...

  10. 46 CFR 116.920 - Storm rails.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Storm rails. 116.920 Section 116.920 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS CARRYING MORE THAN 150... and Guards § 116.920 Storm rails. Suitable storm rails or hand grabs must be installed where...

  11. 46 CFR 177.920 - Storm rails.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Storm rails. 177.920 Section 177.920 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS (UNDER 100 GROSS TONS) CONSTRUCTION AND ARRANGEMENT Rails and Guards § 177.920 Storm rails. Suitable storm rails or hand grabs must...

  12. 46 CFR 127.320 - Storm rails.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Storm rails. 127.320 Section 127.320 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS CONSTRUCTION AND ARRANGEMENTS Rails and Guards § 127.320 Storm rails. Suitable storm rails must be installed in each passageway and...

  13. 46 CFR 108.221 - Storm rails.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Storm rails. 108.221 Section 108.221 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Rails § 108.221 Storm rails. Each unit must have a storm rail in the...

  14. 46 CFR 116.920 - Storm rails.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Storm rails. 116.920 Section 116.920 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS CARRYING MORE THAN 150... and Guards § 116.920 Storm rails. Suitable storm rails or hand grabs must be installed where...

  15. 46 CFR 127.320 - Storm rails.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Storm rails. 127.320 Section 127.320 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS CONSTRUCTION AND ARRANGEMENTS Rails and Guards § 127.320 Storm rails. Suitable storm rails must be installed in each passageway and...

  16. 46 CFR 177.920 - Storm rails.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Storm rails. 177.920 Section 177.920 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS (UNDER 100 GROSS TONS) CONSTRUCTION AND ARRANGEMENT Rails and Guards § 177.920 Storm rails. Suitable storm rails or hand grabs must...

  17. 46 CFR 169.329 - Storm rails.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Storm rails. 169.329 Section 169.329 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Construction and Arrangement Rails and Guards § 169.329 Storm rails. Suitable storm rails or hand grabs must...

  18. 46 CFR 108.221 - Storm rails.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Storm rails. 108.221 Section 108.221 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Rails § 108.221 Storm rails. Each unit must have a storm rail in the...

  19. 46 CFR 169.329 - Storm rails.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Storm rails. 169.329 Section 169.329 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Construction and Arrangement Rails and Guards § 169.329 Storm rails. Suitable storm rails or hand grabs must...

  20. 46 CFR 108.221 - Storm rails.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Storm rails. 108.221 Section 108.221 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Construction and Arrangement Rails § 108.221 Storm rails. Each unit must have a storm rail in the...

  1. Numerical simulations to account for boulder movements on Lanyu Island, Taiwan: tsunami or storm?

    NASA Astrophysics Data System (ADS)

    Nakamura, Mamoru; Arashiro, Yasuhisa; Shiga, Shota

    2014-12-01

    Boulders that originated from the Holocene coral terrace and coral reef are distributed on the coral terrace or talus on the shore of Lanyu Island, Taiwan. We employed numerical simulation of storm waves and estimated whether the boulders could be moved by storm waves with a return period of 50 years, by larger storm waves with return periods of hundreds of years, or by tsunamis. The coral boulders are distributed between 36 and 128 m from the shoreline at elevations of 2.7 to 9.3 m. The sizes of the boulders are in the range 0.3 to 6.4 m. The boulder volume and a-axis length versus distance from the shore show weak and moderate correlation ( r = 0.21 and 0.48), respectively. We reproduced the runup of waves using the equation of continuity for a two-dimensional non-compressive fluid and the Navier-Stokes formula. In order to handle the free surface of the fluid, the volume of fluid method was applied. For the flow velocity to move the boulder, we employed the theoretical formula for the transport of boulders. We used the wave height for a return period of 50 years and set the height of the input wave to 13.1 m. The results show that all the large boulders on Lanyu Island could be moved by storm waves with a return period of 50 years. Moreover, the computations show that most of the boulders could not have been transported by tsunamis generated by the Mw8.7 earthquakes. The ages of two boulders indicate that they were transported after 340 and 6,330 years ago. If these boulders were moved by tsunamis several hundred years ago, they would have been relocated subsequently by storm waves.

  2. Source of microbaroms from tropical cyclone waves

    NASA Astrophysics Data System (ADS)

    Stopa, Justin E.; Cheung, Kwok Fai; GarcéS, Milton A.; Fee, David

    2011-03-01

    Microbaroms are continuous infrasonic signals with a dominant frequency around 0.2 Hz produced by ocean surface waves. Monitoring stations around the globe routinely detect strong microbaroms in the lee of tropical cyclones. We utilize a parametric wind model and a spectral wave model to construct the tropical cyclone wave field and a theoretical acoustic source model to describe the intensity, spatial distribution, and dynamics of microbarom sources. This approach excludes ambient wave conditions and facilitates a parametric analysis to elucidate the source mechanism within the storm. A stationary tropical cyclone produces the strongest microbarom signals at the center, where the waves generated by the cyclonic winds converge. As the tropical cyclone moves forward, the converging wave field becomes less coherent and lags and expands behind the storm center. The models predict a direct relation between the storm forward speed and the location of maximum microbarom source intensity consistent with the infrasonic observations from Hurricane Felicia 2009 in the North Central Pacific.

  3. The geological effects of hurricanes on coral reefs and the interpretation of storm deposits

    NASA Astrophysics Data System (ADS)

    Scoffin, T. P.

    1993-11-01

    Hurricanes occur in belts 7° to 25° north and south of the equator. Reefs growing in these belts suffer periodic damage from hurricane-generated waves and storm surge. Corals down to 20m depth may be broken and removed, branching colonies being much more susceptible to breakage than upright massive forms. Sand cays may be washed away and former storm ridges may migrate to leeward across reef flats to link with islands. Reef crest and reef front coral debris accumulate as talus at the foot of the fore-reef slope, on submarine terraces and grooves, on the intertidal reef flat as storm ridges of shingle or boulders and isolated blocks of reef framework, as accreting beach ridges of leeward migrating shingle, as lobes and wedges of debris in back-reef lagoons, as drapes of carbonate sand and mud in deep off-reef locations in the fore-reef and lagoonal areas. In addition to the coarse debris deposited, other features may aid the recognition of former hurricane events, including the assemblage of reef biota, its species composition and the structure of the skeletons; graded internal sediments in framework cavities; characteristic sequences of encrusting organisms; characteristic shapes of reef flat microatoll corals; and submarine cement crusts over truncated reef surfaces. The abundance of reef flat storm deposits whose ages cluster around 3000 4000 y BP in certain parts of the world most likely relate to a slight fall in relative sea level rather than an increase in storminess during that period. A higher frequency of storms need not result in more reef flat storm deposits. The violence of the storm relative to normal fair-weather conditions influences the extent of damage; the length of time since the previous major storm influences the amount of coral debris created; the length of time after the hurricane, and before a subsequent storm influences the degree of stabilization of reef-top storm deposits and hence their chances of preservation.

  4. Impacts of storms on coastal circulation in Long Bay, South Carolina

    NASA Astrophysics Data System (ADS)

    Kim, H.; Warner, J. C.; Voulgaris, G.; Work, P.

    2006-12-01

    We investigate the effects of coastal storms on the regional circulation in Long Bay, South Carolina, using a coupled ROMS (Regional Ocean Modeling System)- SWAN (Simulating WAves Nearshore) model. Meteorological observations during the South Carolina Coastal Erosion Study (October 2003 April 2004) reveal three dominant types of storms in the region warm fronts, cold fronts, and tropical storms. Each storm has a characteristic progression of wind patterns: (1) Warm fronts start with southwestward winds and change to northeastward after the front passes; (2) Cold fronts begin with northeastward winds and shift to southeastward when the front moves out; and (3) Tropical storms change wind directions from the southwest to the southeast during the storm. It is observed the coastal circulation distinctly responds to such atmospheric disturbances in either a upwelling-favorable condition to the northeastward winds or a downwelling-favorable condition to the southwestward winds. The study domain encompasses 300-km of gently arcing shoreline between Cape Romain to Cape Fear, and approximately 100-km offshore to the shelf edge. The model domain is resolved by a 300×130 mesh at 1-km intervals in the horizontal and twenty terrain-following layers in the vertical. The ROMS model is driven by tides and wind stress, and it includes wave-current interactions via dynamic coupling to the surface wave model SWAN. Salinity and temperature along the open boundaries are included by nudging to climatological values. A time period of six months is simulated from October 2003 to April 2004, concurrent with the observation study. Model results are compared to an extensive set of measurements collected at eight sites in the inner part of Long Bay, and are used to identify varying circulation response to each storm type. In addition, we investigate the significance of the Capes on the development of the alongshore pressure gradients, and examine the importance of wave-current interactions

  5. Atmospheric circulation and storm events in the Black Sea and Caspian Sea

    NASA Astrophysics Data System (ADS)

    Surkova, Galina V.; Arkhipkin, Victor S.; Kislov, Alexander V.

    2013-12-01

    Extreme sea storms are dangerous and a potential source of damage. In this study, we examine storm events in the Black Sea and Caspian Sea, the atmosphere circulation patterns associated with the sea storm events, and their changes in the present (1961-2000) and future (2046-2065) climates. A calendar of storms for the present climate is derived from results of wave model SWAN (Simulating WAves Nearshore) experiments. On the basis of this calendar, a catalog of atmospheric sea level pressure (SLP) fields was prepared from the NCEP/NCAR reanalysis dataset for 1961-2000. The SLP fields were subjected to a pattern recognition algorithm which employed empirical orthogonal decomposition followed by cluster analysis. The NCEP/NCAR reanalysis data is used to evaluate the occurring circulation types (CTs) within the ECHAM5-MPI/OM Atmosphere and Ocean Global Circulation Model (AOGCM) for the period 1961-2000. Our analysis shows that the ECHAM5-MPI/OM model is capable of reproducing circulation patterns for the storm events. The occurrence of present and future ECHAM5-MPI/OM CTs is investigated. It is shown that storm CTs are expected to occur noticeably less frequently in the middle of the 21st century.

  6. Large Geomagnetic Storms: Introduction to Special Section

    NASA Technical Reports Server (NTRS)

    Gopalswamy, N.

    2010-01-01

    Solar cycle 23 witnessed the accumulation of rich data sets that reveal various aspects of geomagnetic storms in unprecedented detail both at the Sun where the storm causing disturbances originate and in geospace where the effects of the storms are directly felt. During two recent coordinated data analysis workshops (CDAWs) the large geomagnetic storms (Dst < or = -100 nT) of solar cycle 23 were studied in order to understand their solar, interplanetary, and geospace connections. This special section grew out of these CDAWs with additional contributions relevant to these storms. Here I provide a brief summary of the results presented in the special section.

  7. Storm Impacts on Potential Pathogens in Estuaries

    NASA Astrophysics Data System (ADS)

    Fries, J. Stephen; Noble, Rachel T.; Kelly, Ginger M.; Hsieh, Jennifer L.

    2007-02-01

    Estuarine and coastal environments are susceptible to a variety of changes driven by tropical storms and hurricanes. The 2005 Atlantic hurricane season impressed upon the public the devastating impacts of storms on coastal populations and the possible social and public health costs. Storm surges and subsequent flooding have the potential to redistribute water and associated contaminants, including a wide range of chemicals and microorganisms. While this impact is difficult to observe through monitoring during larger storms, smaller storms provide opportunities to observe the mechanisms responsible for contaminant and microbial transport.

  8. Storm extreme levels and coastal flood hazards: A parametric approach on the French coast of Languedoc (district of Leucate)

    NASA Astrophysics Data System (ADS)

    Anselme, Brice; Durand, Paul; Thomas, Yves-François; Nicolae-Lerma, Alexandre

    2011-10-01

    Coastal flooding is a significant risk on the shores of Languedoc-Roussillon. The storms that periodically hit the coast can generate strong swells and storm surges. Most beach resorts, built on a low elevation dune ridge, are periodically flooded during major storms. Although risks zoning regulations take into consideration coastal flood hazards, the delineation of vulnerable areas is still insufficient and the commonly accepted threshold is regularly exceeded during most severe storms. This paper presents a method to improve the assessment of extreme storm-related water levels. It relies on fieldwork carried out in the Leucate commune (Aude), which is particularly exposed to the risk of sea level rise. It considers both storm surges and wave phenomena that occur within the surf zone (set-up and swash), calculated from the Simulating WAves Nearshore (SWAN ®) numerical wave model and the Stockdon formula. Water levels reached during several recent storm events have been reconstructed and simulations of submerged areas were carried out by numerical modelling.

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

    PubMed

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

    2013-01-01

    The Indian Ocean tsunami in 2004 and Hurricanes Katrina and Rita in 2005 have spurred global interest in the role of coastal wetlands and vegetation in reducing storm surge and flood damages. Evidence that coastal wetlands reduce storm surge and attenuate waves is often cited in support of restoring Gulf Coast wetlands to protect coastal communities and property from hurricane damage. Yet interdisciplinary studies combining hydrodynamic and economic analysis to explore this relationship for temperate marshes in the Gulf are lacking. By combining hydrodynamic analysis of simulated hurricane storm surges and economic valuation of expected property damages, we show that the presence of coastal marshes and their vegetation has a demonstrable effect on reducing storm surge levels, thus generating significant values in terms of protecting property in southeast Louisiana. Simulations for four storms along a sea to land transect show that surge levels decline with wetland continuity and vegetation roughness. Regressions confirm that wetland continuity and vegetation along the transect are effective in reducing storm surge levels. A 0.1 increase in wetland continuity per meter reduces property damages for the average affected area analyzed in southeast Louisiana, which includes New Orleans, by $99-$133, and a 0.001 increase in vegetation roughness decreases damages by $24-$43. These reduced damages are equivalent to saving 3 to 5 and 1 to 2 properties per storm for the average area, respectively. PMID:23536815

  10. The Value of Wetlands in Protecting Southeast Louisiana from Hurricane Storm Surges

    PubMed Central

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

    2013-01-01

    The Indian Ocean tsunami in 2004 and Hurricanes Katrina and Rita in 2005 have spurred global interest in the role of coastal wetlands and vegetation in reducing storm surge and flood damages. Evidence that coastal wetlands reduce storm surge and attenuate waves is often cited in support of restoring Gulf Coast wetlands to protect coastal communities and property from hurricane damage. Yet interdisciplinary studies combining hydrodynamic and economic analysis to explore this relationship for temperate marshes in the Gulf are lacking. By combining hydrodynamic analysis of simulated hurricane storm surges and economic valuation of expected property damages, we show that the presence of coastal marshes and their vegetation has a demonstrable effect on reducing storm surge levels, thus generating significant values in terms of protecting property in southeast Louisiana. Simulations for four storms along a sea to land transect show that surge levels decline with wetland continuity and vegetation roughness. Regressions confirm that wetland continuity and vegetation along the transect are effective in reducing storm surge levels. A 0.1 increase in wetland continuity per meter reduces property damages for the average affected area analyzed in southeast Louisiana, which includes New Orleans, by $99-$133, and a 0.001 increase in vegetation roughness decreases damages by $24-$43. These reduced damages are equivalent to saving 3 to 5 and 1 to 2 properties per storm for the average area, respectively. PMID:23536815

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

    PubMed

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

    2013-01-01

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

  12. Total electron content behavior over Japan during geomagnetic storms

    NASA Astrophysics Data System (ADS)

    Kutiev, Ivan; Watanabe, Shigeto; Otsuka, Yoichi; Saito, Akinori

    2005-01-01

    The total electron content (TEC) obtained from GPS signals is used to study ionospheric dynamics over Japan during geomagnetically disturbed conditions. The numerous TEC measurements are averaged in cells with a size 1.5° × 1.5° geographic scale and formatted as time series within the years 2000-2002. To extract the storm time changes of TEC, the diurnal and 27-day periodicities are subsequently removed. Diurnal variations are removed by replacing absolute TEC values in each cell with their relative deviations (RTEC) from medians. The hourly RTEC values from all cells within the central 4°-wide band over Japan area are then approximated by a plane surface. This surface is represented by two parameters: its value at the center (rt) and the slope (b) along the main axis, taken as constants of the linear regression. The 27-day periodicity was approximated by Fourier waves with main period of 640 hours and two harmonics separately for rt and b and subtracted from them. The analysis of rt and b behavior during a number of geomagnetic storms allowed us to reveal several repeatable features of average TEC behavior. It was found that TEC behavior during the storms is similar to that of foF2 at the F region and was local time-dependent. A marked poleward expansion of the equatorial ionosphere (crest region) at the end of recovery phase is persistently observed feature, produced probably by intensified eastward zonal winds. Such an expansion of equatorial ionosphere is observed also during isolated substorms, outside main geomagnetic storms. An oscillation-like change of positive and negative disturbances with period of 24 hours is observed during a 4-day period, following a moderate storm. In the absence of geomagnetic activity driver that effect is probably caused by the alternative expansion and contraction of equatorial ionosphere.

  13. Outer shelf storm deposits of Upper Cretaceous Chico Formation, California

    SciTech Connect

    Russell, J.S.

    1987-05-01

    The Kingsley Cave member of the Upper Cretaceous Chico Formation, northeastern Sacramento Valley, California, is an outer shelf sequence consisting of muddy siltstones deposited below storm wave base. Silty fine-grained sandstone interbeds, interpreted as distal tempestites, are common within this member and are typically parallel laminated and devoid of shell material. Fossil concentrations within this member are rare, occurring as internally simple lenses within fine-grained sandstone interbeds. These fossil concentrations are up to 1.0 m in thickness. The faunas within these lenses are allochthonous or, less commonly, parautochthonous. Comparisons of the faunas in these shell lenses with published faunal assemblages for the Chico Formation and other Upper Cretaceous west coast nearshore deposits indicate that they were displaced from shallower-water environments. Lenses typically contain faunal elements of shoreface and inner shelf environments, which were located to the east during this time, as well as outer shelf faunal elements. These fossil concentrations are sedimentologic in origin. The scoured bases and overlying hummocky cross-stratified to ripple laminated siltstones of these lenses, their relative thicknesses, and the allochthonous shallower-water faunal elements contained within them are all characteristics of proximal tempestites, normally found within inner shelf sandstones. Distal tempestites, typical of outer shelf facies, are the norm for the Kingsley Cave member, while these proximal tempestites are the exception. The former were deposited by normal-strength storm events, while the latter are indicative of rare, extremely high-intensity storm events. During these extremely high-intensity storms proximality trends shifted seaward (westward), causing proximal tempestites to form more offshore than the proximal tempestites generated by normal-strength storms.

  14. Storms of Mediterranean and Atlantic legends

    NASA Astrophysics Data System (ADS)

    Schoenenwald, N.; Tabeaud, M.

    2009-09-01

    Weather extremes and notably wind storms are very often the channel ones since they are suspected of being the outward signs of climate change. However, even if audiovisual medias talk about wind storms in a very similar way, tales and legends stories account for the richness of their representations. Coastal and insular regions, whatever Atlantic or Mediterranean, are the ones where wind storms are most mentioned. The comparison between the tales and legends of these two regions, with distinct climatic characteristics, allows to underline the similarities and dissimilarities about the impregnation (or impact) of wind storms on these territories. Winds and storms distinguish spaces through vocabulary which can be peculiar to a region. Nevertheless, they also bring them together because above the local cultures is the human thought upon which wind storms create comparable perceptions, whatever the region. Key words: wind storms, Mediterranean regions, Atlantic regions, perceptions, representations.

  15. [Diagnosis and treatment of thyroid storm].

    PubMed

    Akamizu, Takashi

    2012-11-01

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

  16. Thyroid storm precipitated by duodenal ulcer perforation.

    PubMed

    Natsuda, Shoko; Nakashima, Yomi; Horie, Ichiro; Ando, Takao; Kawakami, Atsushi

    2015-01-01

    Thyroid storm is a rare and life-threatening complication of thyrotoxicosis that requires prompt treatment. Thyroid storm is also known to be associated with precipitating events. The simultaneous treatment of thyroid storm and its precipitant, when they are recognized, in a patient is recommended; otherwise such disorders, including thyroid storm, can exacerbate each other. Here we report the case of a thyroid storm patient (a 55-year-old Japanese male) complicated with a perforated duodenal ulcer. The patient was successfully treated with intensive treatment for thyroid storm and a prompt operation. Although it is believed that peptic ulcer rarely coexists with hyperthyroidism, among patients with thyroid storm, perforation of a peptic ulcer has been reported as one of the causes of fatal outcome. We determined that surgical intervention was required in this patient, reported despite ongoing severe thyrotoxicosis, and reported herein a successful outcome.

  17. Energetic ions upstream of the earth's bow shock during an energetic storm particle event

    NASA Technical Reports Server (NTRS)

    Scholer, M.; Ipavich, F. M.

    1983-01-01

    Simultaneous observations of low-energy protons and alpha particles from ISEE 3 far upstream and from ISEE 1 close to the earth's bow shock during the passage of an interplanetary shock wave with its associated energetic storm particles are presented. Intensities, spectra, and anisotropies of the energetic storm particles are modified due to the interaction of these particles with the earth's bow shock. An intensity spike observed at ISEE 1 during the passage of the interplanetary shock is interpreted as being due to postacceleration of energetic storm particles at the bow shock by the first-order Fermi mechanism. The spikes observed at ISEE 1 after the passage of the interplanetary shock are most probably due to reflection of the energetic storm particles at the bow shock.

  18. The responses of the thermosphere due to a geomagnetic storm: A MHD model

    NASA Technical Reports Server (NTRS)

    Wu, S. T.; Chang, S.

    1972-01-01

    A magnetohydrodynamics theory was used to study the dynamic response of the neutral atmosphere to a geomagnetic storm. A full set of magnetohydrodynamic equations appropriate for the present problem is derived and their various orders of approximation are discussed in some detail. In order to demonstrate the usefulness of this theoretical model, the May 1967 geomagnetic storm data were used in the resulting set of nonlinear, time dependent, partial differential magnetohydrodynamic equations to calculate variations of the thermosphere due to the storm. The numerical results are presented for wind speeds, electric field strength, and amount of joule heating at a constant altitude for the data recorded. Data show that the strongest thermospheric responses are at the polar region becoming weaker in the equatorial region. This may lead to the speculation that a thermospheric wave is generated in the polar region due to the geomagnetic storm which propagates towards the equator.

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

    NASA Astrophysics Data System (ADS)

    Kettle, Anthony

    2016-04-01

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

  20. Spectral features of background ULF noise during magnetic storms

    NASA Astrophysics Data System (ADS)

    Kotik, Dmitry; Ermakova, Elena; Ryabov, Alexander; Shchecoldin, Aexander

    The monitoring of tangential components of ULF noise below first Schumann resonance was permanently provided since 2003 up to now at mid-latitude station New Life (56N, 44,7E). The regular structure in ULF spectrograms named SRS -spectral resonance structure could be observed practically every night excepting years of solar activity maximum. The SRS appears in the ULF noise due existing the resonator for Alfven waves in the ionosphere at heights from the bottom up to 600 -1000 km [1]. It was noticed that during magnetically disturbed time the strong anti-correlation between the intensity of SRS events and K index from station on neighbor magnetic meridian [2]. For more detail investigation it was choused several magnetic storms. First one is storm witch has began at November 20, 2003 with maximum Kp=9 (strong), second -at March 19, 2006 with Kp=6+ (moderate) and the third -at November 25, 2008 with Kp=5 (weak). The spectra of magnetic component amplitude and polarization parameter were analyzed. The comparison with ionosond and magnetic field data as well as world TEC maps for mentioned storm periods were made. The dynamics of changing the properties of ULF spectra during the storms were explored. The general regularities of these changes were displayed. One of the prominent feathers appeared at the end of the strong and moderate storms looked like fish shoals. Perhaps this kind of ULF bursts is the same nature as well known pearls pulsation but displayed in broad frequency range 1-6 Hz. May be it could be classified as special spectral structure. The analysis of changing the properties of ULF spectra during the storms together with geo-physical data has shown that the main regularities in changes the SRS caused by changing of the ionospheric parameters above the observation point. But some of ULF spectral features are results of interaction waves and particles in the magnetosphere. 1. Belyaev P.P., Polyakov S.V., Ermakova E.N., Isaev S.V. Solar cycle variations in

  1. Dust storm off Western Africa

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The impacts of Saharan dust storms reach far beyond Africa. Wind-swept deserts spill airborne dust particles out over the Atlantic Ocean where they can enter trade winds bound for Central and North America and the Caribbean. This Moderate Resolution Imaging Spectroradiometer (MODIS) image shows a dust storm casting an opaque cloud of cloud across the Canary Islands and the Atlantic Ocean west of Africa on June 30, 2002. In general it takes between 5 and 7 days for such an event to cross the Atlantic. The dust has been shown to introduce foreign bacteria and fungi that have damaged reef ecosystems and have even been hypothesized as a cause of increasing occurrences of respiratory complaints in places like Florida, where the amount of Saharan dust reaching the state has been increasing over the past 25 years.

  2. Rogue waves in oceanic turbulence

    NASA Astrophysics Data System (ADS)

    Fedele, Francesco

    2008-08-01

    A stochastic model of wave groups is presented to explain the occurrence of exceptionally large waves, usually referred to as rogue waves. The model leads to the description of the non-Gaussian statistics of large waves in oceanic turbulence and to a new asymptotic distribution of their crest heights in a form that generalizes the Tayfun model. The new model explains the unusually large crests observed in flume experiments of narrow-band waves. However, comparisons with realistic oceanic measurements gathered in the North Sea during an intense storm indicate that the generalized model agrees with the original Tayfun distribution.

  3. Severe storms observing satellite study

    NASA Technical Reports Server (NTRS)

    Iwens, R. P.; Stern, D. A.

    1976-01-01

    Payload distribution and the attitude control system for the multi-mission modular spacecraft/StormSat configuration are discussed. The design of the advanced atmospheric sounder and imaging radiometer (AASIR) gimbal drive and its servomechanism is described. Onboard data handling, data downlink communications, and ground data handling systems are developed. Additional topics covered include: magnetic unloading at synchronous altitude, north-south stationkeeping, and the feasibility and impact of flying the microwave atmospheric sounding radiometer (MASR) as an additional payload.

  4. Dust Storm in Southern California

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Along historic Route 66, just southeast of the little town of Amboy, California, lies a dried-up lake. Dry lakebeds are good sources of two things: salt and dust. In this image, the now-parched Bristol Lake offers up both. On April 12, 2007, dust storms menaced the area around Amboy. To the northwest, near Newberry Springs, California, dust hampered visibility and led to a multi-car collision on Interstate 40, killing two people and injuring several others. The same day, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite captured this image of a dust storm in the dry remains of Bristol Lake. Many small dust clouds boil up from the ground surface, casting their shadows to the northwest. A bright white cloud floating over the dust also throws its shadow onto the ground below. East of the dust storm are salt works that stand out from the surrounding landscape thanks to their straight lines and sharp angles. Dark ground surfaces alternate with mined white salt in a network of stripes. When lakes evaporate, chemicals that had been dissolved in the water stay behind, making dry lake beds an ideal place to find heavy concentrations of minerals, including salt. Besides the salt works, something else appears in stark contrast to this arid place. Lush green fields of irrigated crops appear in the east. Besides their color, their orderly arrangement reveals their human-made origin.

  5. Wallops severe storms measurement capability

    NASA Technical Reports Server (NTRS)

    Carr, R. E.; Gerlach, J. C.

    1981-01-01

    Some of the instrumentation system used in support of NASA'S Storm Hazards Program are described. These systems include the Radar Atmospheric Research Facility (RARF) with its Space Range Radar and a near real time display from the National Weather Service WSR-57 radar, a lightning detection and ranging system (LDAR), and a Ryan Stormscope. The RARF system can detect, track, and quantify the properties of severe storms. Simultaneous measurements in the UHF (70 cm), S (10 cm), and C (5 cm) bands can be made of clouds and precipitation to deduce particle size and characteristics, including quantitive cross sections of individual hailstones and raindrops. Relative attenuation at these wavelenghts can be used to calculate path integrated rainfall and water content. The track of an instrument aircraft can be displayed on S-band reflectivity map of the individual storm cells. The LDAR system can determine the location of lightning discharges in real time and measure and record the electric field waveform for further study. The Ryan Stormscope can detect and range lightning out to 320 kilometers.

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

    USGS Publications Warehouse

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

    2007-01-01

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

  7. The Sources of Bz Fluctuations within CIRs: Magnetic Storms During the Descending Phase of the Solar Cycle

    NASA Technical Reports Server (NTRS)

    Sakurai, R. K.; Tsurutani, B. T.; Ho, C. M.; Arballo, J. K.; Smith, E. J.; Goldstein, B. E.; Balogh, A.

    1995-01-01

    This presentation examines the magnetic field fluctuations within Corotating Interaction Regions (CIRs) detected by Ulysses at mid- and low-latitudes. CIRs are formed by the interaction of high-speed streams flowing from the polar coronal hole with slow-speed streams. Several wave modes are identified, and the effectiveness of these waves causing magnetic storms at Earth will be discussed.

  8. Morphological abnormalities in elasmobranchs.

    PubMed

    Moore, A B M

    2015-08-01

    A total of 10 abnormal free-swimming (i.e., post-birth) elasmobranchs are reported from The (Persian-Arabian) Gulf, encompassing five species and including deformed heads, snouts, caudal fins and claspers. The complete absence of pelvic fins in a milk shark Rhizoprionodon acutus may be the first record in any elasmobranch. Possible causes, including the extreme environmental conditions and the high level of anthropogenic pollution particular to The Gulf, are briefly discussed.

  9. Chromosome abnormalities in glioma

    SciTech Connect

    Li, Y.S.; Ramsay, D.A.; Fan, Y.S.

    1994-09-01

    Cytogenetic studies were performed in 25 patients with gliomas. An interesting finding was a seemingly identical abnormality, an extra band on the tip of the short arm of chromosome 1, add(1)(p36), in two cases. The abnormality was present in all cells from a patient with a glioblastoma and in 27% of the tumor cells from a patient with a recurrent irradiated anaplastic astrocytoma; in the latter case, 7 unrelated abnormal clones were identified except 4 of those clones shared a common change, -Y. Three similar cases have been described previously. In a patient with pleomorphic astrocytoma, the band 1q42 in both homologues of chromosome 1 was involved in two different rearrangements. A review of the literature revealed that deletion of the long arm of chromosome 1 including 1q42 often occurs in glioma. This may indicate a possible tumor suppressor gene in this region. Cytogenetic follow-up studies were carried out in two patients and emergence of unrelated clones were noted in both. A total of 124 clonal breakpoints were identified in the 25 patients. The breakpoints which occurred three times or more were: 1p36, 1p22, 1q21, 1q25, 3q21, 7q32, 8q22, 9q22, 16q22, and 22q13.

  10. [Congenital foot abnormalities].

    PubMed

    Delpont, M; Lafosse, T; Bachy, M; Mary, P; Alves, A; Vialle, R

    2015-03-01

    The foot may be the site of birth defects. These abnormalities are sometimes suspected prenatally. Final diagnosis depends on clinical examination at birth. These deformations can be simple malpositions: metatarsus adductus, talipes calcaneovalgus and pes supinatus. The prognosis is excellent spontaneously or with a simple orthopedic treatment. Surgery remains outstanding. The use of a pediatric orthopedist will be considered if malposition does not relax after several weeks. Malformations (clubfoot, vertical talus and skew foot) require specialized care early. Clubfoot is characterized by an equine and varus hindfoot, an adducted and supine forefoot, not reducible. Vertical talus combines equine hindfoot and dorsiflexion of the forefoot, which is performed in the midfoot instead of the ankle. Skew foot is suspected when a metatarsus adductus is resistant to conservative treatment. Early treatment is primarily orthopedic at birth. Surgical treatment begins to be considered after walking age. Keep in mind that an abnormality of the foot may be associated with other conditions: malposition with congenital hip, malformations with syndromes, neurological and genetic abnormalities. PMID:25524290

  11. Coastal morphodynamic impacts induced by main storm phenomena on the Central East Tyrrhenian Sea

    NASA Astrophysics Data System (ADS)

    Marcelli, Marco; Paladini de Mendoza, Francesco; Bonamano, Simone; Scanu, Sergio; Martellucci, Riccardo

    2015-04-01

    The coastal area is a major dynamic systems of the Earth and in particular the sandy beaches are very sensitive to waves energy variation which mainly force morphological changes. Waves drive beaches morphological changes particularly when they exceed a determined threshold. In a short term (from hours to days) of storm conditions, intense erosion phenomena occur. They generate overwash, dunal erosion, loss of lands, damage to engineering structures and coastal ownerships. Several hazardous weather events take place every year in the Mediterranean region and cause relevant economic losses. The western Mediterranean Sea is an area subjected to cyclonic activity. In winter and during the negative phase of North Atlantic Oscillation (NAO), cyclonic activity generates extreme events as intense precipitation, the highest waves, landslides and surges. The study area is the Latium coast, eastern side of Central Tyrrhenian Sea.Wave data were measured by three wave buoys. In order to obtain a better spatial coverage useful to take into account the waves variability over the study area, wave data also has been calculated by WAM model. On the basis of storms events selected by a threshold criteria of events greater than 2 m for a period more than 6 hour, the Mean Sea Level Pressure (MSLP) field was analysed through Empirical Orthogonal Function and cluster analysis obtaining 3 classes of barometric events. The storms are always induced by the lows of Gulf of Genoa to be formed in the Mediterranean region triggered from the middle latitude storms which center is located in the northern atlantic and scandinavian region. The different classes, with a probability of 28%, 23% and 49%, generate different circulation driving waves from different directions. The classes of storms show spatial differences in terms of main directions but show similar behavior in terms of distribution of wave direction. In this study the wave and wind field induced by the different barometric condition

  12. Boulder Dislodgement by Tsunamis and Storms: Version 2.0

    NASA Astrophysics Data System (ADS)

    Weiss, R.; Diplas, P.; Kaihatu, J. M.; Sheremet, A.

    2015-12-01

    In the past, boulder dislodgement by tsunami and storm waves has been approached with a simple threshold approach in which a boulder was moved if the sum of the acting forces on the boulder is larger than zero. The impulse theory taught us, however, that this criterion is not enough to explain particle dislodgement. We employ an adapted version of the Newton's Second Law of Motion (NSLM) in order to consider the essence of the impulse theory which is that the sum of the forces has to exceed a certain threshold for a certain period of time. Furthermore, a classical assumption is to consider linear waves. However, when waves travel toward the shore, they alter due to non-linear processes. We employ the TRIADS model to quantify that change and how it impacts boulder dislodgement. We present our results of the coupled model (adapted NSLM and TRIADS model). The results project a more complex picture of boulder transport by storms and tsunami. The following question arises: What information do we actually invert, and what does it tell us about the causative event?

  13. Boulder Dislodgement by Tsunamis and Storms: Version 2.0

    NASA Astrophysics Data System (ADS)

    Weiss, Robert

    2016-04-01

    In the past, boulder dislodgement by tsunami and storm waves has been approached with a simple threshold approach in which a boulder was moved if the sum of the acting forces on the boulder is larger than zero. The impulse theory taught us, however, that this criterion is not enough to explain particle dislodgement. We employ an adapted version of the Newton's Second Law of Motion (NSLM) in order to consider the essence of the impulse theory which is that the sum of the forces has to exceed a certain threshold for a certain period of time. Furthermore, a classical assumption is to consider linear waves. However, when waves travel toward the shore, they alter due to non-linear processes. We employ the TRIADS model to quantify that change and how it impacts boulder dislodgement. We present our results of the coupled model (adapted NSLM and TRIADS model). The results project a more complex picture of boulder transport by storms and tsunami. The following question arises: What information do we actually invert, and what does it tell us about the causative event?

  14. Shallow-water seismoacoustic noise generated by tropical storms Ernesto and Florence.

    PubMed

    Traer, James; Gerstoft, Peter; Bromirski, Peter D; Hodgkiss, William S; Brooks, Laura A

    2008-09-01

    Land-based seismic observations of double frequency (DF) microseisms generated during tropical storms Ernesto and Florence are dominated by signals in the 0.15-0.5 Hz band. In contrast, data from sea floor hydrophones in shallow water (70 m depth, 130 km off the New Jersey coast) show dominant signals in the ocean gravity-wave frequency band, 0.02-0.18 Hz, and low amplitudes from 0.18 to 0.3 Hz, suggesting significant opposing wave components necessary for DF microseism generation were negligible at the site. Florence produced large waves over deep water while Ernesto only generated waves in coastal regions, yet both storms produced similar spectra. This suggests near-coastal shallow water as the dominant region for observed microseism generation.

  15. Abnormal pressures as hydrodynamic phenomena

    USGS Publications Warehouse

    Neuzil, C.E.

    1995-01-01

    So-called abnormal pressures, subsurface fluid pressures significantly higher or lower than hydrostatic, have excited speculation about their origin since subsurface exploration first encountered them. Two distinct conceptual models for abnormal pressures have gained currency among earth scientists. The static model sees abnormal pressures generally as relict features preserved by a virtual absence of fluid flow over geologic time. The hydrodynamic model instead envisions abnormal pressures as phenomena in which flow usually plays an important role. This paper develops the theoretical framework for abnormal pressures as hydrodynamic phenomena, shows that it explains the manifold occurrences of abnormal pressures, and examines the implications of this approach. -from Author

  16. Understanding Storm Time Poynting Flux Variability

    NASA Astrophysics Data System (ADS)

    Garner, H. M.; Ober, D. M.; Wilson, G. R.

    2012-12-01

    It is known that energy deposited by dayside Earth-directed Poynting flux (S||) is greater during geomagnetic storms; however, S|| spatial and temporal variability are less well understood. Eight years (2000-2008) of data from the WDC for Geomagnetism, Kyoto, were collected to identify thirteen large and five super storms according to specific criteria: "classic" storm structure in which the time interval between sudden storm commencement (SSC) and minimum Dst (Dstmin) was ≤ 24 hours; the main and recovery phases did not experience secondary or tertiary disturbances; large storms where Dst ≤ -93 nT; and, super storms where Dst ≤ -184 nT. Solar wind and magnetospheric data for the 18 storms were collected from the Defense Meteorological Satellite Program (DMSP F-15) and NASA OMNI. For all storms, the data were averaged and plotted to identify S|| variability for the mantle, cusp, polar rain, and central and boundary layer plasma sheet regions during geomagnetic storm time. As known for all storms, while Dst decreased, average S|| peaked, as did Kp. The energy deposited per square-meter by precipitating energetic particles (electrons) did not increase, though average hemispheric power increased by nearly a factor of two for the large and super storms between SSC and Dstmin. For the large storms, average S|| from the central and boundary layer plasma sheet regions (on closed field lines) was enhanced by nearly a factor of two between SSC and Dstmin; for the super storms, enhancement was over a factor of three. Average large storm S|| enhancement from the mantle, cusp, and polar rain regions (on open field lines) was significantly more enhanced by a factor of three between SSC and Dstmin. It was enhanced by a factor of over five for the super storms. For the open field line regions, a large, prolonged secondary peak in S|| was observed for large and super storms during the recovery phase. As suggested by this and prior studies, research is needed to better

  17. Understanding impacts of tropical storms and hurricanes on submerged bank reefs and coral communities in the northwestern Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Lugo-Fernández, A.; Gravois, M.

    2010-06-01

    A 100-year climatology of tropical storms and hurricanes within a 200-km buffer was developed to study their impacts on coral reefs of the Flower Garden Banks (FGB) and neighboring banks of the northwestern Gulf of Mexico. The FGB are most commonly affected by tropical storms from May through November, peaking in August-September. Storms approach from all directions; however, the majority of them approach from the southeast and southwest, which suggests a correlation with storm origin in the Atlantic and Gulf of Mexico. A storm activity cycle lasting 30-40 years was identified similar to that known in the Atlantic basin, and is similar to the recovery time for impacted reefs. On average there is 52% chance of a storm approaching within 200 km of the FGB every year, but only 17% chance of a direct hit every year. Storm-generated waves 5-25 m in height and periods of 11-15 s induce particle speeds of 1-4 m s -1 near these reefs. The wave-current flow is capable of transporting large (˜3 cm) sediment particles, uplifting the near-bottom nepheloid layer to the banks tops, but not enough to break coral skeletons. The resulting storm-driven turbulence induces cooling by heat extraction, mixing, and upwelling, which reduces coral bleaching potential and deepens the mixed layer by about 20 m. Tropical storms also aid larvae dispersal from and onto the FGB. Low storm activity in 1994-2004 contributed to an 18% coral cover increase, but Hurricane Rita in 2005 reduced it by 11% and brought coral cover to nearly pre-1994 levels. These results suggest that the FGB reefs and neighboring reef banks act as coral refugia because of their offshore location and deep position in the water column, which shields them from deleterious effects of all but the strongest hurricanes.

  18. Feeling Abnormal: Simulation of Deviancy in Abnormal and Exceptionality Courses.

    ERIC Educational Resources Information Center

    Fernald, Charles D.

    1980-01-01

    Describes activity in which student in abnormal psychology and psychology of exceptional children classes personally experience being judged abnormal. The experience allows the students to remember relevant research, become sensitized to the feelings of individuals classified as deviant, and use caution in classifying individuals as abnormal.…

  19. A probabilistic storm surge risk model for the German North Sea and Baltic Sea coast

    NASA Astrophysics Data System (ADS)

    Grabbert, Jan-Henrik; Reiner, Andreas; Deepen, Jan; Rodda, Harvey; Mai, Stephan; Pfeifer, Dietmar

    2010-05-01

    module to account for specific (re-) insurance conditions. This contribution will mainly concentrate on the hazard module. The hazard is covered by an event simulation engine enabling Monte Carlo simulations. The event generation is done on-the-fly. A classification of historical storm surges is used based on observed sea water levels at gauging stations and extended literature research. To characterize the origin of storm events and storm surges caused by those, also meteorological parameters like wind speed and wind direction are being used. If high water levels along the coast are mainly caused by strong wind from particular directions as observed at the North Sea, there is a clear empirical relationship between wind and surge (where surge is defined as the wind-driven component of the sea water level) which can be described by the ATWS (Average Transformed Wind speed). The parameters forming the load at the coastal defense elements are water level and wave parameters like significant wave height, wave period and wave direction. To assess the wave characteristics at the coast the numerical model SWAN (Simulating Waves Near Shore) from TU Delft has been used. To account for different probabilities of failure and inundation the coast is split into segments with similar defense characteristics like type of defense, height, width, orientation and others. The chosen approach covers the most relevant failure mechanisms for coastal dikes induced by wave overtopping and overflow. Dune failure is also considered in the model. Inundation of the hinterland after defense failure is modeled using a simple dynamical 2d-approach resulting in distributed water depths and flood outlines for each segment. Losses can be estimated depending on the input exposure data either coordinate based for single buildings or aggregated on postal code level using a set of depths-damage functions.

  20. The storm-time equatorial electrojet

    NASA Technical Reports Server (NTRS)

    Burrows, K.; Sastry, T. S. G.; Sampath, S.; Stolarik, J. D.; Usher, M. J.

    1976-01-01

    A Petrel rocket carrying a double cell rubidium magnetometer was launched from the Thumba Equatorial Rocket Launching Station during the early main phase of a magnetic storm. No ionospheric currents associated with the storm were observed and the large field depression, at the flight time, must therefore be attributed to currents at higher altitudes. The equatorial enhancement of ionospheric magnetic storm currents, predicted on the basis of theory and earlier ground data, was not observed.

  1. The storm-time equatorial electrojet

    NASA Technical Reports Server (NTRS)

    Burrows, K.; Sastry, T. S. G.; Sampath, S.; Stolarik, J. D.; Usher, M. J.

    1977-01-01

    A Petrel rocket carrying a double cell rubidium magnetometer was launched from the Thumba Equatorial Rocket Launching Station during the early main phase of a magnetic storm. No ionospheric currents associated with the storm were observed, and the large field depression at the flight time must therefore be attributed to currents at higher altitudes. The equatorial enhancement of ionospheric magnetic storm currents, predicted on the basis of theory and earlier ground data, was not observed.

  2. NASA's Radiation Belt Storm Probes (RBSP) Mission

    NASA Astrophysics Data System (ADS)

    Fox, Nicola; Mauk, Barry; Ukhorskiy, Aleksandr; Takahashi, Kazue; Sibeck, David; Grebowsky, Joseph; Kessel, Ramona

    Understanding of radiation belt physics has matured to the extent that we have identified a set of processes which interplay to cause the creation and variation of radiation populations. These universal processes operate coherently across the planetary radiation belts of the solar system, and have far reaching impacts even beyond. Improvements in our understanding of these processes will substantially enhance our ability to predict radiation dynamics and mitigate the impacts on space assets. An important link in developing fully predictive understanding of such processes is the Radiation Belt Storm Probes mission to be launched into Earth's radiation belts in 2012 as a part of NASA's Living with a Star program. RBSP comprises two spacecraft making in situ measurements for at least 2 years in nearly the same highly elliptical, low inclination orbits (1.1 x 5.8 RE, 10 degrees). The orbits are slightly different so that 1 spacecraft laps the other spacecraft about every 2.5 months, allowing separation of spatial from temporal affects over spatial scales ranging from 0.1 to 5 RE. The unusually comprehensive suite of instruments, identical on the two spacecraft, measures the particle spectra (electrons, ions, ion compositions), fields (E and B), and wave distributions (dE and dB) that are needed to resolve the most critical science questions. Here we describe the RBSP mission characteristics, review the most pressing science issues that need to be resolved to develop predictive understanding, and describe how RBSP will be used to resolve those issues.

  3. Topographic Correction Module at Storm (TC@Storm)

    NASA Astrophysics Data System (ADS)

    Zaksek, K.; Cotar, K.; Veljanovski, T.; Pehani, P.; Ostir, K.

    2015-04-01

    Different solar position in combination with terrain slope and aspect result in different illumination of inclined surfaces. Therefore, the retrieved satellite data cannot be accurately transformed to the spectral reflectance, which depends only on the land cover. The topographic correction should remove this effect and enable further automatic processing of higher level products. The topographic correction TC@STORM was developed as a module within the SPACE-SI automatic near-real-time image processing chain STORM. It combines physical approach with the standard Minnaert method. The total irradiance is modelled as a three-component irradiance: direct (dependent on incidence angle, sun zenith angle and slope), diffuse from the sky (dependent mainly on sky-view factor), and diffuse reflected from the terrain (dependent on sky-view factor and albedo). For computation of diffuse irradiation from the sky we assume an anisotropic brightness of the sky. We iteratively estimate a linear combination from 10 different models, to provide the best results. Dependent on the data resolution, we mask shades based on radiometric (image) or geometric properties. The method was tested on RapidEye, Landsat 8, and PROBA-V data. Final results of the correction were evaluated and statistically validated based on various topography settings and land cover classes. Images show great improvements in shaded areas.

  4. Convective storms in planetary atmospheres

    NASA Astrophysics Data System (ADS)

    Hueso, R.; Sánchez-Lavega, A.

    2013-05-01

    The atmospheres of the planets in the Solar System have different physical properties that in some cases can be considered as extreme when compared with our own planet's more familiar atmosphere. From the tenuous and cold atmosphere of Mars to the dense and warm atmosphere of Venus in the case of the terrestrial planets, to the gigantic atmospheres of the outer planets, or the nitrogen and methane atmosphere of Saturn's moon Titan, we can find a large variety of physical environments. The comparative study of these atmospheres provides a better understanding of the physics of a geophysical fluid. In many of these worlds convective storms of different intensity appear. They are analogous to terrestrial atmospheres fed by the release of latent heat when one of the gases in the atmosphere condenses and they are therefore called moist convective storms. In many of these planets they can produce severe meteorological phenomena and by studying them in a comparative way we can aspire to get a further insight in the dynamics of these atmospheres even beyond the scope of moist convection. A classical example is the structure of the complex systems of winds in the giant planets Jupiter and Saturn. These winds are zonal and alternate in latitude but their deep structure is not accessible to direct observation. However the behaviour of large--scale convective storms vertically extending over the "weather layer" allows to study the buried roots of these winds. Another interesting atmosphere with a rather different structure of convection is Titan, a world where methane is close to its triple point in the atmosphere and can condense in bright clouds with large precipitation fluxes that may model part of the orography of the surface making Titan a world with a methane cycle similar to the hydrological cycle of Earth's atmosphere.

  5. Abnormal human sex chromosome constitutions

    SciTech Connect

    1993-12-31

    Chapter 22, discusses abnormal human sex chromosome constitution. Aneuploidy of X chromosomes with a female phenotype, sex chromosome aneuploidy with a male phenotype, and various abnormalities in X chromosome behavior are described. 31 refs., 2 figs.

  6. Exercises to Improve Gait Abnormalities

    MedlinePlus

    ... Home About iChip Articles Directories Videos Resources Contact Exercises to Improve Gait Abnormalities Home » Article Categories » Exercise and Fitness Font Size: A A A A Exercises to Improve Gait Abnormalities Next Page The manner ...

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

    NASA Astrophysics Data System (ADS)

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

    2006-06-01

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

  8. Observing storm surges from satellite altimetry

    NASA Astrophysics Data System (ADS)

    Han, Guoqi

    2016-07-01

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

  9. On the watch for geomagnetic storms

    USGS Publications Warehouse

    Green, Arthur W.; Brown, William M.

    1997-01-01

    Geomagnetic storms, induced by solar activity, pose significant hazards to satellites, electrical power distribution systems, radio communications, navigation, and geophysical surveys. Strong storms can expose astronauts and crews of high-flying aircraft to dangerous levels of radiation. Economic losses from recent geomagnetic storms have run into hundreds of millions of dollars. With the U.S. Geological Survey (USGS) as the lead agency, an international network of geomagnetic observatories monitors the onset of solar-induced storms and gives warnings that help diminish losses to military and commercial operations and facilities.

  10. A Personal Storm Warning Service

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Although lightning detection systems operated by government agencies, utilities and other businesses provide storm warnings, this information often does not reach the public until some time after the observations have been made. A low-cost personal lightning detector offers a significant safety advantage to private flyers, boaters, golfers and others. Developed by Airborne Research Associates, the detectors originated in Space Shuttle tests of an optical lightning detection technique. The commercial device is pointed toward a cloud to detect invisible intracloud lightning by sensing subtle changes in light presence. The majority of the sales have been to golf courses. Additional products and more advanced applications are in progress.

  11. Storms On Venus: Lightning-induced Chemistry And Predicted Products

    NASA Astrophysics Data System (ADS)

    Delitsky, M. L.; Baines, K. H.

    2012-10-01

    Observations by many spacecraft that have visited Venus over the last 40 years appear to confirm the presence of lightning storms in the Venus atmosphere. Recent observations by Venus Express indicate that lightning frequency and power is similar to that on Earth. While storms are occurring, energy deposition by lightning into Venus atmospheric constituents will immediately dissociate molecules into atoms, ions and plasma from the high temperatures in the lightning column (>30,000 K) and the associated shock waves and heating, after which these atom and ion fragments will recombine during cooldown to form new sets of molecules. Lightning will re-sort the atoms of C,O,S,N,H to create highly energetic new products. Spark and discharge experiments in the literature suggest that lightning effects on the main atmospheric molecules CO2, N2, SO2, H2SO4 and H2O will yield new molecules such as mixed carbon oxides (CnOm), mixed sulfur oxides (SnOm), oxygen (O2), elemental sulfur (Sn), nitrogen oxides (NO, N2O, NO2, NO3), sulfuric acid clusters (HnSmOx-.aHnSmOx e.g. HSO4-.mH2SO4), polysulfur oxides, carbon soot, and also halogen oxides from HCl or HF and other exotic species. Many of these molecular species may be detectable by instruments onboard Venus Express. We explore the diversity of new products likely created in the storm clouds on Venus.

  12. Storm-generated variations in nearshore beach topography

    USGS Publications Warehouse

    Lins, H.F.

    1984-01-01

    A series of nearshore beach profile measurements from the Outer Banks of North Carolina spanning a four-month period have been examined for temporal variations in nearshore topography. Principal component analysis of the profile data indicates that most of the variation in nearshore topography occurs in four principal modes, two quasiseasonal and two subseasonal. The first principal component, or eigenvector, corresponds to a bar-berm function. The second, to a terrace function. Combined, the first two vectors explain 76.3% of the total variance. The third and fourth components, representing subseasonal modes, are a ridge and runnel and a storm bar function, respectively. Both occur in direct response to storm wave activity. Although the bar-berm and terrace modes of profile variation have been previously identified using principal component analysis techniques, the subsequent modes have not. The ridge and runnel function accounts for 10.6% of total profile variability and the storm bar function accounts for 5.0%. ?? 1985.

  13. Gravity wave initiated convection

    NASA Technical Reports Server (NTRS)

    Hung, R. J.

    1990-01-01

    The vertical velocity of convection initiated by gravity waves was investigated. In one particular case, the convective motion-initiated and supported by the gravity wave-induced activity (excluding contributions made by other mechanisms) reached its maximum value about one hour before the production of the funnel clouds. In another case, both rawinsonde and geosynchronous satellite imagery were used to study the life cycles of severe convective storms. Cloud modelling with input sounding data and rapid-scan imagery from GOES were used to investigate storm cloud formation, development and dissipation in terms of growth and collapse of cloud tops, as well as, the life cycles of the penetration of overshooting turrets above the tropopause. The results based on these two approaches are presented and discussed.

  14. Abnormal ionization in sonoluminescence

    NASA Astrophysics Data System (ADS)

    Zhang, Wen-Juan; An, Yu

    2015-04-01

    Sonoluminescence is a complex phenomenon, the mechanism of which remains unclear. The present study reveals that an abnormal ionization process is likely to be present in the sonoluminescing bubble. To fit the experimental data of previous studies, we assume that the ionization energies of the molecules and atoms in the bubble decrease as the gas density increases and that the decrease of the ionization energy reaches about 60%-70% as the bubble flashes, which is difficult to explain by using previous models. Project supported by the Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20120002110031) and the National Natural Science Foundation of China (Grant No. 11334005).

  15. Optimal index related to the shoreline dynamics during a storm: the case of Jesolo beach

    NASA Astrophysics Data System (ADS)

    Archetti, Renata; Paci, Agnese; Carniel, Sandro; Bonaldo, Davide

    2016-05-01

    The paper presents an application of shoreline monitoring aimed at understanding the response of a beach to single storms and at identifying its typical behaviour, in order to be able to predict shoreline changes and to properly plan the defence of the shore zone. On the study area, in Jesolo beach (northern Adriatic Sea, Italy), a video monitoring station and an acoustic wave and current profiler were installed in spring 2013, recording, respectively, images and hydrodynamic data. The site lacks previous detailed hydrodynamic and morphodynamic data. Variations in the shoreline were quantified in combination with available near-shore wave conditions, making it possible to analyse the relationship between the shoreline displacement and the wave features. Results denote characteristic patterns of beach response to storm events, and highlight the importance of improving beach protection in this zone, notwithstanding the many interventions experimented in the last decades. A total of 31 independent storm events were selected during the period October 2013-October 2014, and for each of them synthetic indexes based on storm duration, energy and maximum wave height were developed and estimated. It was found that the net shoreline displacements during a storm are well correlated with the total wave energy associated to the considered storm by an empirical power law equation. A sub-selection of storms in the presence of an artificial dune protecting the beach (in the winter season) was examined in detail, allowing to conclude that the adoption of this coastal defence strategy in the study area can reduce shoreline retreat during a storm. This type of intervention can sometimes contribute to prolonging overall stability not only in the replenished zone but also in downdrift areas. The implemented methodology, which confirms to be economically attractive if compared to more traditional monitoring systems, proves to be a valuable system to monitor beach erosive

  16. Best index related to the shoreline dynamics during a storm: the case of Jesolo beach

    NASA Astrophysics Data System (ADS)

    Archetti, R.; Paci, A.; Carniel, S.; Bonaldo, D.

    2015-11-01

    The paper presents an application of shoreline monitoring aimed to understand the response of a beach to single storms and to identify its typical behaviour, in order to be able to predict shoreline changes and to properly plan the defence of the shore zone. On the study area, in Jesolo beach (Nothern Adriatic sea, Italy), a video monitoring station and an acoustic wave and current profiler were installed in spring 2013, recording respectively images and hydrodynamic data. The site lacks of previous detailed hydrodynamic and morphodynamics data. Variations in the shoreline were quantified in combination with available nearshore wave conditions, making it possible to analyse a relationship between the shoreline displacement and the wave features. Results denote characteristic patterns of beach response to storm events, and highlight the importance of improving beach protection in this zone, notwithstanding the many interventions experimented in the last decades. A total of 31 independent storm events were selected during the period October 2013-October 2014, and for each of them synthetic indexes based on storm duration, energy and maximum wave height were developed and estimated. It was found that the mean shoreline displacements during a storm are well correlated with the total wave energy during the considered storm by an empirical power law equation. A sub-selection of storms on beach protected by artificial dunes (in winter season) was examined in detail; we can conclude that the extensive adoption of artificial dunes in the study area was useful in the past also to reduce shoreline retreat during the storm. This type of interventions can sometimes contribute to prolonged overall stability not only in the replenished zone but also in down drift areas. The implemented methodology, which confirms to be economically attractive if compared to more traditional monitoring systems, proves to be a valuable system to monitor beach erosive processes and provide detailed

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

    USGS Publications Warehouse

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

    2009-01-01

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

  18. Abnormal hematological indices in cirrhosis

    PubMed Central

    Qamar, Amir A; Grace, Norman D

    2009-01-01

    Abnormalities in hematological indices are frequently encountered in cirrhosis. Multiple causes contribute to the occurrence of hematological abnormalities. Recent studies suggest that the presence of hematological cytopenias is associated with a poor prognosis in cirrhosis. The present article reviews the pathogenesis, incidence, prevalence, clinical significance and treatment of abnormal hematological indices in cirrhosis. PMID:19543577

  19. Rock Coasts on the Move: Boulder morphodynamics during the March 2008 storm, Wales UK

    NASA Astrophysics Data System (ADS)

    Naylor, Larissa; Stephenson, Wayne; Smith, Helen; Mendelssohn, James; Cowley, Andrew

    2010-05-01

    There is growing research suggesting that coastal boulders can be entrained, transported and deposited by storm events as well as tsunamis. This research has typically documented decadal to century timescale changes in intertidal, supra-tidal or cliff-top boulder deposits. Indeed, there are no known studies of contemporaneous boulder transport studies in coastal environments (Goto et al., 2009). The nature of boulder transport mechanisms and modes during storm events is therefore unexplored. Researchers have suggested possible modes of transport, including rolling, sliding, flipping, or carried in suspension. These have yet to be observed during storm events. This paper presents the first-known dataset of intertidal boulder morphodynamics during a storm event. We present daily data from the 9th-13th of March 2008, capturing pre-storm, storm and post-storm boulder positions. Field data on boulder position was collected using a differential GPS, alongside observations of boulder position, orientation and boulder size. Data were plotted in GIS, and using a series of python scripts were analysed to measure distance and direction travelled. Wave data from Turbot Bank buoy was modelled using SWAN. These data plus tidal records were compared to the field measurements of boulder movements, to identify relationships between wave force and measured boulder movements. The majority of boulders sampled were entrained and transported during the 3 day storm event, with one boulder having moved over 60 metres during the storm. Daily observations also enabled us to draw conclusions about the various modes by which boulders were transported. Some were flipped, others were carried in suspension, whilst more slid or were rolled across the shore platform surface. Three new boulders were detached during the storm event, on two separate days. Boulder breakdown was also observed and quantified. Results show that daily data enabled us to better understand and quantify boulder

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

    ERIC Educational Resources Information Center

    Curtis, Scott

    2013-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Luettich, R.; Westerink, J. J.

    2010-12-01

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

  2. Alfvénic field-aligned currents, ion upflow and electron precipitation during large geomagnetic storms

    NASA Astrophysics Data System (ADS)

    Hatch, Spencer; LaBelle, James; Chaston, Christopher

    2016-04-01

    We present four years of FAST observations of Alfvénic field-aligned currents (FACs) in the Northern Hemisphere coincident with 40 moderate (Dst < -50 nT) to very large geomagnetic storms. Superposed epoch analysis of Alfvénic activity of storm periods demonstrate a sharp increase in the probability of AlfvÉn wave occurrence just after storm commencement, and analysis based on storm phase shows that the probability of Alfvén wave occurrence increases by more than a factor of 5 on both dayside and nightside. Additionally, recently reported Van Allen Probes measurements in the magnetosphere imply a region (˜60-68 degrees invariant latitude) in the nightside ionosphere where Alfvén waves are statistically likely to be observed during storm main phase; we report statistical observations during main phase showing that this region instead corresponds to both intense electron precipitation (>10 mW m-2) and strong upflowing ion number flux (> 108 cm^{-2 s-1), while observed Alfvénic FAC occurrence rates are diminished relative to Van Allen Probes measurements. FAST observations also indicate that the most intense electron precipitation associated with Alfvénic FACs occurs pre-midnight during storm recovery phase.

  3. Impacts on the Deep-Sea Ecosystem by a Severe Coastal Storm

    PubMed Central

    Sanchez-Vidal, Anna; Canals, Miquel; Calafat, Antoni M.; Lastras, Galderic; Pedrosa-Pàmies, Rut; Menéndez, Melisa; Medina, Raúl; Company, Joan B.; Hereu, Bernat; Romero, Javier; Alcoverro, Teresa

    2012-01-01

    Major coastal storms, associated with strong winds, high waves and intensified currents, and occasionally with heavy rains and flash floods, are mostly known because of the serious damage they can cause along the shoreline and the threats they pose to navigation. However, there is a profound lack of knowledge on the deep-sea impacts of severe coastal storms. Concurrent measurements of key parameters along the coast and in the deep-sea are extremely rare. Here we present a unique data set showing how one of the most extreme coastal storms of the last decades lashing the Western Mediterranean Sea rapidly impacted the deep-sea ecosystem. The storm peaked the 26th of December 2008 leading to the remobilization of a shallow-water reservoir of marine organic carbon associated with fine particles and resulting in its redistribution across the deep basin. The storm also initiated the movement of large amounts of coarse shelf sediment, which abraded and buried benthic communities. Our findings demonstrate, first, that severe coastal storms are highly efficient in transporting organic carbon from shallow water to deep water, thus contributing to its sequestration and, second, that natural, intermittent atmospheric drivers sensitive to global climate change have the potential to tremendously impact the largest and least known ecosystem on Earth, the deep-sea ecosystem. PMID:22295084

  4. Investigation of Ring Current Response to CIR-Driven Geomagnetic Storms

    NASA Astrophysics Data System (ADS)

    Cramer, William Douglas

    The physics of ring current behavior during Coronal Mass Ejection (CME)-driven storms is well understood and can be modeled with moderate accuracy. The effects of Corotating Interaction Region (CIR)-driven storms are less understood and tend to not agree with expected values. Various approaches are employed to examine the differences in ring current behavior during storms driven by these two types of events. Satellite data (Polar CAM-MICE/MICS) are analyzed to determine differences in pitch angle distributions and energy densities, in order to provide insight into how the various ring current enhancement and loss processes differ during the different types of events. A ring current model (the Comprehensive Ring Current Model) is also employed to analyze these differences by modeling ring current behavior during CME and CIR events that fit a typical solar wind profile. No differences in convection were noted in satellite data during CME and CIR-driven storms of similar strength, although oxygen was found to contribute more to the energy density during CIRs. However, model results demonstrated that there is a significant difference in ring current response during storms associated with the different drivers. It was determined that particle convection appears to be the primary ring current energization mechanism for CME-driven events, while other factors seem to influence the induced surface magnetic disturbance during CIR-driven storms; possibly boundary conditions, external currents or fluctuations caused by the associated wave-induced oscillations in the solar wind.

  5. Impacts on the deep-sea ecosystem by a severe coastal storm.

    PubMed

    Sanchez-Vidal, Anna; Canals, Miquel; Calafat, Antoni M; Lastras, Galderic; Pedrosa-Pàmies, Rut; Menéndez, Melisa; Medina, Raúl; Company, Joan B; Hereu, Bernat; Romero, Javier; Alcoverro, Teresa

    2012-01-01

    Major coastal storms, associated with strong winds, high waves and intensified currents, and occasionally with heavy rains and flash floods, are mostly known because of the serious damage they can cause along the shoreline and the threats they pose to navigation. However, there is a profound lack of knowledge on the deep-sea impacts of severe coastal storms. Concurrent measurements of key parameters along the coast and in the deep-sea are extremely rare. Here we present a unique data set showing how one of the most extreme coastal storms of the last decades lashing the Western Mediterranean Sea rapidly impacted the deep-sea ecosystem. The storm peaked the 26(th) of December 2008 leading to the remobilization of a shallow-water reservoir of marine organic carbon associated with fine particles and resulting in its redistribution across the deep basin. The storm also initiated the movement of large amounts of coarse shelf sediment, which abraded and buried benthic communities. Our findings demonstrate, first, that severe coastal storms are highly efficient in transporting organic carbon from shallow water to deep water, thus contributing to its sequestration and, second, that natural, intermittent atmospheric drivers sensitive to global climate change have the potential to tremendously impact the largest and least known ecosystem on Earth, the deep-sea ecosystem.

  6. Characteristics of sea-cliff erosion induced by a strong winter storm in the eastern Mediterranean

    NASA Astrophysics Data System (ADS)

    Katz, Oded; Mushkin, Amit

    2013-07-01

    Changes in sea-cliff morphologies along the 30-km-long Sharon Escarpment segment of Israel's weakly cemented Mediterranean eolianite cliff line were analyzed to gain quantitative insights into erosion characteristics associated with a high-energy winter storm (10-20 year return interval). Ground-based repeat LiDAR measurements at five sites along the cliff line captured perturbations of cliff stability by basal wave scouring during the storm, subsequent post-storm gravity-driven slope failures in the cliff face above, and return of the system to transient stability within several months. Post-storm erosion, which amounted to 70% of the total volume of cliff erosion documented, resulted in dramatic local effects of up to 8 m of cliff-top retreat. And yet, at the larger scale of the 30-km cliff line examined, erosion during the storm and the year that followed affected less than 4% of the cliff length and does not appear to be above the average cliff-length annual erosion implied by previously published decadal-scale retreat rates along this sea cliff. Our results do not support a direct association between strong storm events and elevated erosion and retreat at the cliff-line scale.

  7. Dependency of the North Pacific winter storm tracks on the zonal distribution of MJO convection

    NASA Astrophysics Data System (ADS)

    Lee, Yun-Young; Lim, Gyu-Ho

    2012-07-01

    We investigate the effects of the tropical Madden Julian Oscillation (MJO) convection on the zonal location and intensity of storm activity during the boreal cool season (Nov. 1 to Feb. 28, 120 days) over the Pacific Ocean. As tropical convection shifts eastward from the eastern Indian Ocean to the western North Pacific, MJO-induced local Hadley circulation leads to an eastward displacement of extratropical Rossby Wave Source (RWS). Consequently, this influence leads to an eastward shift of the peak area of the storm track. The storm track is strongest with the MJO convection over the eastern Indian Ocean (phase 3), and it experiences the suppression when MJO convection is located over the Maritime continents (phase 4), and it increases again when the MJO propagates to the western Pacific (phase 5), after which it weakens again (phase 6). The intensity of the storm track, particularly over the western North Pacific (120°E-180°), is determined by the integrated effects of three factors: the midlatitude convective forcing (MCF), the jet stream, and RWS. These factors are associated with the locations of MJO convections. It is estimated that MJO-induced suppression accounts for only 2.5% of the total observed midwinter suppression (MWS). However, the pattern generated by the MJO is remarkably similar to the observed meridional displacement of North Pacific storm track associated with sub-seasonal variation. We conclude that the spatial distribution of MJO affects the variation of the Pacific storm track, but is not a cause of the MWS.

  8. Possible Cosmic Ray Using for Forecasting of Major Geomagnetic Storms, Accompanied by Forbush-Effects

    NASA Astrophysics Data System (ADS)

    Dorman, L. I.; Belov, A. V.; Eroshenko, E. A.; Pustil'Nik, L. A.; Sternlieb, A.; Yanke, V. G.; Zukerman, I. G.

    2003-07-01

    We present developing of methods for forecasting on the basis of NM hourly on-line data geomagnetic storms accompanied by Forbush-effects. These geomagnetic storms are dangerous for technology (influence on power systems, on spacecraft operations, on HF radio-communications and others) and people health. We show that for esp ecially dangerous geomagnetic storms can be used global-sp ectrographic method if on-line will be available 35-40 NM of world-wide net. In this case for each hour can be determined CR anisotropy vector, and the specifically behavior of this vector before SC of geomagnetic storms can be used as important factor for forecast. The second factor is specifically behavior of CR density for about 30-15 hours before SC (pre-increase effect, caused mainly by galactic CR particles acceleration during interaction with shock wave moved from the Sun). The third factor is effect of cosmic ray pre-decreasing, caused by magnetic connection of the Earth with the region behind the shock wave. We demonstrate developing methods on several examples of ma jor geomagnetic storms. This research is partly supported by the EU INTAS grant 00-0810.

  9. Understanding Variability in Beach Slope to Improve Forecasts of Storm-induced Water Levels

    NASA Astrophysics Data System (ADS)

    Doran, K. S.; Stockdon, H. F.; Long, J.

    2014-12-01

    The National Assessment of Hurricane-Induced Coastal Erosion Hazards combines measurements of beach morphology with storm hydrodynamics to produce forecasts of coastal change during storms for the Gulf of Mexico and Atlantic coastlines of the United States. Wave-induced water levels are estimated using modeled offshore wave height and period and measured beach slope (from dune toe to shoreline) through the empirical parameterization of Stockdon et al. (2006). Spatial and temporal variability in beach slope leads to corresponding variability in predicted wave setup and swash. Seasonal and storm-induced changes in beach slope can lead to differences on the order of a meter in wave runup elevation, making accurate specification of this parameter essential to skillful forecasts of coastal change. Spatial variation in beach slope is accounted for through alongshore averaging, but temporal variability in beach slope is not included in the final computation of the likelihood of coastal change. Additionally, input morphology may be years old and potentially very different than the conditions present during forecast storm. In order to improve our forecasts of hurricane-induced coastal erosion hazards, the temporal variability of beach slope must be included in the final uncertainty of modeled wave-induced water levels. Frequently collected field measurements of lidar-based beach morphology are examined for study sites in Duck, North Carolina, Treasure Island, Florida, Assateague Island, Virginia, and Dauphin Island, Alabama, with some records extending over a period of 15 years. Understanding the variability of slopes at these sites will help provide estimates of associated water level uncertainty which can then be applied to other areas where lidar observations are infrequent, and improve the overall skill of future forecasts of storm-induced coastal change. Stockdon, H. F., Holman, R. A., Howd, P. A., and Sallenger Jr, A. H. (2006). Empirical parameterization of setup

  10. Spirometric abnormalities among welders

    SciTech Connect

    Rastogi, S.K.; Gupta, B.N.; Husain, T.; Mathur, N.; Srivastava, S. )

    1991-10-01

    A group of manual welders age group 13-60 years having a mean exposure period of 12.4 {plus minus} 1.12 years were subjected to spirometry to evaluate the prevalence of spirometric abnormalities. The welders showed a significantly higher prevalence of respiratory impairment than that observed among the unexposed controls as a result of exposure to welding gases which comprised fine particles of lead, zinc, chromium, and manganese. This occurred despite the lower concentration of the pollutants at the work place. In the expose group, the smoking welders showed a prevalence of respiratory impairment significantly higher than that observed in the nonsmoking welders. The results of the pulmonary function tests showed a predominantly restrictive type of pulmonary impairment followed by a mixed ventilatory defect among the welders. The effect of age on pulmonary impairment was not discernible. Welders exposed for over 10 years showed a prevalence of respiratory abnormalities significantly higher than those exposed for less than 10 years. Smoking also had a contributory role.

  11. Global Pc5 pulsations during strong magnetic storms: excitation mechanisms and equatorward expansion

    NASA Astrophysics Data System (ADS)

    Marin, J. A.; Pilipenko, V.; Vega, P.; Zesta, E.; Stepanova, M. V.; Uozumi, T.

    2012-12-01

    The spatial structure of Pc5 waves during the recovery phases of strong magnetic storms is important not only for the identification of possible physical mechanisms of its excitation, but as an important parameter of the ULF driver of relativistic electrons. The dynamics of global Pc5 waves during the magnetic storms on October 29-31, 2003 and May 15, 2005 is studied, using the data from the trans-American network of magnetometers comprising SAMBA, MAGDAS, CARISMA, and MACCS arrays. We study the behavior of Pc5 wave properties and spectral characteristics with respect to latitude. One of the accepted sources of Pc5 wave activity is Kelvin-Helmholtz instability in the flanks of the magnetosphere. In our study we examine whether the KH instability is sufficient as an excitation mechanism for the observed waves? More specifically, we attempt to determine, what is the Pc5 wave generation type: self-excitation, resonant response, trigger? While the KH instability generation takes place at the outer flanks of the magnetosphere, Pc5 waves are observed at all latitudes. We determine how deep into the magnetosphere these Pc5 waves activity can extend and what is the wave energy transmission mechanism: surface mode, cavity mode, Alfven field-line resonance, magnetospheric MHD waveguide?

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

    NASA Astrophysics Data System (ADS)

    Santiago, J. T.

    2015-12-01

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

  13. Coastal storm monitoring in Virginia

    USGS Publications Warehouse

    Wicklein, Shaun M.; Bennett, Mark

    2014-01-01

    Coastal communities in Virginia are prone to flooding, particularly during hurricanes, nor’easters, and other coastal low-pressure systems. These weather systems affect public safety, personal and public property, and valuable infrastructure, such as transportation, water and sewer, and electric-supply networks. Local emergency managers, utility operators, and the public are tasked with making difficult decisions regarding evacuations, road closures, and post-storm recovery efforts as a result of coastal flooding. In coastal Virginia these decisions often are made on the basis of anecdotal knowledge from past events or predictions based on data from monitoring sites located far away from the affected area that may not reflect local conditions. Preventing flood hazards, such as hurricane-induced storm surge, from becoming human disasters requires an understanding of the relative risks that flooding poses to specific communities. The risk to life and property can be very high if decisions about evacuations and road closures are made too late or not at all.

  14. Spring Dust Storm Smothers Beijing

    NASA Technical Reports Server (NTRS)

    2002-01-01

    A few days earlier than usual, a large, dense plume of dust blew southward and eastward from the desert plains of Mongolia-quite smothering to the residents of Beijing. Citizens of northeastern China call this annual event the 'shachenbao,' or 'dust cloud tempest.' However, the tempest normally occurs during the spring time. The dust storm hit Beijing on Friday night, March 15, and began coating everything with a fine, pale brown layer of grit. The region is quite dry; a problem some believe has been exacerbated by decades of deforestation. According to Chinese government estimates, roughly 1 million tons of desert dust and sand blow into Beijing each year. This true-color image was made using two adjacent swaths (click to see the full image) of data from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS), flying aboard the OrbView-2 satellite, on March 17, 2002. The massive dust storm (brownish pixels) can easily be distinguished from clouds (bright white pixels) as it blows across northern Japan and eastward toward the open Pacific Ocean. The black regions are gaps between SeaWiFS' viewing swaths and represent areas where no data were collected. Image courtesy the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

  15. Severe Local Storms Cultural Heritage

    NASA Astrophysics Data System (ADS)

    Gladich, I.; Gallai, I.; Giaiotti, D. B.; Morgan, G. M.; Stel, F.

    2009-09-01

    Local storms always had a deep impact on people communities, mainly because of the severe damage caused, because of their unpredictability and, up to a few years ago, even because of the lack of knowledge and awareness on their physical origin. Because of this large impact on real life and on imagination, people needed and wanted to describe and report the occurrence of these events, giving them suited names. Often, these nouns are related to the myth developed to explain the cause of the events. In this work, a short presentation and description of the popular nouns used to describe severe local storm events in different areas of the World is given. Countries taken into account span from Italy, moving toward Africa and reaching a few communities of Native Americans. The etymology of the names gives interesting information, useful even under the anthropological point of view, on the Culture and Believes of the peoples who adopted them. This research work is the result of an underground activity carried out in the last ten years by the authors, during their contacts with students and researchers coming from different Countries and mainly met at the International Center for Theoretical Physics in Trieste.

  16. Comparison Of TES FFSM Eddies And MOC Storms MY 24-26

    NASA Astrophysics Data System (ADS)

    Noble, John; Haberle, R. M.; Bridger, A. F. C.; Wilson, R. J.; Barnes, J. R.; Hollingsworth, J. L.; Cantor, B. A.

    2012-10-01

    Mars Global Surveyor (MGS) orbiter observed a planet-encircling dust storm (PDS) in Mars year (MY) 25 from Ls=176.2-263.4°. Although PDSs occur on an irregular basis, all well-documented storms have begun within ± 75° of Ls from perihelion (Ls=251°) when insolation is greatest near the SH summer solstice (Ls=270°) and the south polar cap is receding. PDS seasonal occurrence suggests the presence of climatic/environmental precursors and components, yet interannual variability suggests that initiation and expansion mechanisms are not solely seasonal in character. We have integrated and examined all available MGS data in order to better understand and characterize the dynamical processes responsible for MY 25 PDS initiation and expansion. Here we present an examination of Mars Orbiter Camera (MOC) dust storms and transient baroclinic eddies identified from Fast Fourier Synoptic Mapping (FFSM) of Thermal Emission Spectrometer (TES) temperatures for the first two phases of the storm: precursor, Ls=176.2- 184.7°, and expansion, Ls=184.7-193°. FFSM analysis of TES 3.7 hPa thermal data shows the presence of eastward-traveling waves at 60° S with a period of about three sols. We hypothesize that these waves are transient baroclinic eddies that contributed to the initiation of precursor storms near Hellas. An examination of the spatial and temporal relationship of FFSM eddies and MOC storms suggests an interesting association between eastward eddy propagation and eastward storm evolution. Determining the factors responsible for PDS genesis in MY 25 and not 24 and 26 is difficult. The most notable difference is the amplitude of E1-E7 eddies in Hellas, with all seven MY 25 eddies colder than -3.5 K, compared with three in MY 24 and two in MY 26. It is possible that the sustained series of high-amplitude eddies in MY 25 was a factor in PDS interannual variability.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  18. Binocular combination in abnormal binocular vision.

    PubMed

    Ding, Jian; Klein, Stanley A; Levi, Dennis M

    2013-02-08

    We investigated suprathreshold binocular combination in humans with abnormal binocular visual experience early in life. In the first experiment we presented the two eyes with equal but opposite phase shifted sine waves and measured the perceived phase of the cyclopean sine wave. Normal observers have balanced vision between the two eyes when the two eyes' images have equal contrast (i.e., both eyes contribute equally to the perceived image and perceived phase = 0°). However, in observers with strabismus and/or amblyopia, balanced vision requires a higher contrast image in the nondominant eye (NDE) than the dominant eye (DE). This asymmetry between the two eyes is larger than predicted from the contrast sensitivities or monocular perceived contrast of the two eyes and is dependent on contrast and spatial frequency: more asymmetric with higher contrast and/or spatial frequency. Our results also revealed a surprising NDE-to-DE enhancement in some of our abnormal observers. This enhancement is not evident in normal vision because it is normally masked by interocular suppression. However, in these abnormal observers the NDE-to-DE suppression was weak or absent. In the second experiment, we used the identical stimuli to measure the perceived contrast of a cyclopean grating by matching the binocular combined contrast to a standard contrast presented to the DE. These measures provide strong constraints for model fitting. We found asymmetric interocular interactions in binocular contrast perception, which was dependent on both contrast and spatial frequency in the same way as in phase perception. By introducing asymmetric parameters to the modified Ding-Sperling model including interocular contrast gain enhancement, we succeeded in accounting for both binocular combined phase and contrast simultaneously. Adding binocular contrast gain control to the modified Ding-Sperling model enabled us to predict the results of dichoptic and binocular contrast discrimination experiments

  19. Influence of resonance on tide and storm surge in the Gulf of Thailand

    NASA Astrophysics Data System (ADS)

    Tomkratoke, Saifhon; Sirisup, Sirod; Udomchoke, Veerasak; Kanasut, Jirawat

    2015-10-01

    A numerical simulation is used to determine the effective resonance period, quality factor Q and linear friction coefficient and mechanism of tide and storm surge in the Gulf of Thailand. The results indicated that the resonance response is triggered by the forced wave with the period of 20.25 hours. The Q factor and linear friction coefficient are approximately 3.15 and 2.76×10-5 ms-1, respectively. The gulf is regarded as a moderately dissipative system, which may yield small amplification for the oscillating forced wave. The resonance structure of the basin can play an important role in spatial distribution and amplification of tidal waves in the Gulf of Thailand and nearby area. Distance from the effective resonance period and the corresponding Q factor can be employed in characterizing of tidal amplification in the gulf. The study found that phase difference in the incoming tidal waves can induce the distortion of a nodal band to the normal mode analysis results. The resonance in the north-south direction is the principal mechanism to control tidal waves, specifically for the upper part of the gulf (the Gulf of Thailand). However, significant effect of resonance in the west-east direction on the amplification of tidal waves near the southern part of the gulf (Vietnam, Malaysia and Singapore coast) may be pronounced. From the reproduced historic storm surge and hypothetical results, the spatial distribution of storm surge elevation and the response ratio are in good agreement with the resonance mode and Q factor of the basin. Individually, the contribution of resonance factor to induce severe storm surge (positive surge) tends to be insignificant. Conversely, the interaction process between the disturbance system and the propagating surge wave in the gulf can induce large positive surge near the landfall location significantly.

  20. Simulating complex storm surge dynamics: Three-dimensionality, vegetation effect, and onshore sediment transport

    NASA Astrophysics Data System (ADS)

    Lapetina, Andrew; Sheng, Y. Peter

    2015-11-01

    The 3-D hydrodynamics of storm surge events, including the effects of vegetation and impact on onshore transport of marine sediment, have important consequences for coastal communities. Here, complex storm surge dynamics during Hurricane Ike are investigated using a three-dimensional (3-D), vegetation-resolving storm surge-wave model (CH3D-SWAN) which includes such effects of vegetation as profile drag, skin friction, and production, dissipation, and transport of turbulence. This vegetation-resolving 3-D model features a turbulent kinetic energy (TKE) closure model, which uses momentum equations with vegetation-induced profile and skin friction drags, a dynamic q2 equation including turbulence production and dissipation by vegetation, as well as vegetation-dependent algebraic length-scale equations, and a Smagorinsky-type horizontal turbulence model. This vegetation model has been verified using extensive laboratory tests, but this study is a comparison of 2-D and 3-D simulations of complex storm surge dynamics during Hurricane Ike. We examine the value of 3-D storm surge models relative to 2-D models for simulating coastal currents, effects of vegetation on surge, and sediment transport during storm events. Comparisons are made between results obtained using simple 2-D formulations for bottom friction, the Manning coefficient (MC) approach, and physics-based 3-D vegetation-modeling (VM) approach. Last, the role that the 3-D hydrodynamics on onshore transport and deposition of marine sediments during the storm is investigated. While both the 3-D and 2-D results simulated the water level dynamics, results of the physics-based 3-D VM approach, as compared to the 2-D MC approach, more accurately captures the complex storm surge dynamics.

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  2. Long-term increase in New York Harbor storm tides, 1844-present

    NASA Astrophysics Data System (ADS)

    Talke, S. A.; Orton, P. M.; Jay, D. A.

    2014-12-01

    Eight of the largest twenty recorded water levels in the New York Harbor region recorded since 1821 occurred after 1990, and three of the 10 largest have occurred since 2010 (March 2010, August 2011, and October 2012). Archival research and numerical modeling indicates, however, that the storm surge during an 1821 hurricane exceeded that from hurricane Sandy (~3.5m vs. 2.8m). To investigate flood risk we recover archival tide gauge data back to 1844 and evaluate whether the recent cluster of extreme water levels is random, driven solely by sea-level rise, or is caused by changes to storm tides (the sum of storm surge and tidal effects). Results indicate both long term trends and decadal variability in the annual maximum storm tide (AMST). Approximately half of long-term AMST variability is explained by a long term increase in storm tides, while the remainder is explained by the North Atlantic Oscillation. The magnitude of the 10 year return period storm tide has increased by 0.28m. Combined with a 0.44m increase in local sea level since 1856, the 10 year flood level has increased by approximately 0.72 ± 0.25m, and magnified the annual probability of overtopping the nominal Manhattan seawall from less than 1% to about 20-25%. Further, including the 1821 event in extreme value analysis suggests that the return period of hurricane Sandy storm tides is much smaller than other estimates. Though the cause of the long-term AMST trend is unclear, analysis of tidal properties indicates that long-wave propagation in New York harbor has shifted since the 1850s. Because storm surge is also a long-wave with a component in the tidal band, at least a portion of changed storm-tide hazard is likely driven by local anthropogenic alterations of the region's waterways. Along with sea-level rise, local development and climate-induced shifts to the North Atlantic Oscillation may continue to affect the New York harbor storm tide hazard in the future.

  3. NASA's 3-D Animation of Tropical Storm Ulika from Space

    NASA Video Gallery

    An animated 3-D flyby of Tropical Storm Ulika using GPM's Radar data showed some strong convective storms inside the tropical storm were dropping precipitation at a rate of over 187 mm (7.4 inches)...

  4. Normothermic thyroid storm: an unusual presentation

    PubMed Central

    Sabir, Anas Ahmad; Sada, Kabiru; Yusuf, Bashir O.; Aliyu, Idris

    2016-01-01

    Thyroid storm is a rare life-threatening emergency due to thyrotoxicosis. A 30-year-old female presented with restlessness, tachycardia and vomiting but with normothermia which is an unusual presentation. There is the need for clinicians to be aware of atypical clinical features that can make the diagnosis of thyroid storm difficult. PMID:27540465

  5. Global differences between moderate and large storms

    NASA Astrophysics Data System (ADS)

    Valek, P. W.; Buzulukova, N.; Fok, M. C. H.; Goldstein, J.; Keesee, A. M.; McComas, D. J.; Perez, J. D.

    2015-12-01

    The current solar maximum has been relatively quiet compared to previous solar cycles. Whereas numerous moderate storms (Dst < -50 nT) have occurred, there have been only a small number of large (Dst < - 100 nT) and extreme (Dst < -200 nT) storms. Throughout this sequence of storms, the Two Wide-angle Imaging Neutral-atom Spectrometers (TWINS) mission has since 2008 observed the inner magnetosphere. TWINS consists of two ENA cameras flown aboard two separate spacecraft in Molniya orbits. TWINS images the ENA emissions from the inner magnetosphere across a broad range of energies (1 to 100 keV for H, 16 to 256 keV for O). This allows TWINS to observe the evolution in space and time of the trapped and precipitating particles most relevant for storm time dynamics on very high time scales (i.e., minutes). Here we will present the differences seen between moderate storms and the two large storms of 17 March 2015 (Dst < -223, St. Patrick's day storm) and 22 June 2015 (Dst < -195 nT). We will present composition-separated ENA observations of the inner magnetosphere covering the both the medium (1 to 30 keV) and high (30 to > 100 keV) energy ranges, and describe how the inner magnetosphere evolves during storm time.

  6. Severe storms and local weather research

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Developments in the use of space related techniques to understand storms and local weather are summarized. The observation of lightning, storm development, cloud development, mesoscale phenomena, and ageostrophic circulation are discussed. Data acquisition, analysis, and the development of improved sensor and computer systems capability are described. Signal processing and analysis and application of Doppler lidar data are discussed. Progress in numerous experiments is summarized.

  7. Normothermic thyroid storm: an unusual presentation.

    PubMed

    Sabir, Anas Ahmad; Sada, Kabiru; Yusuf, Bashir O; Aliyu, Idris

    2016-08-01

    Thyroid storm is a rare life-threatening emergency due to thyrotoxicosis. A 30-year-old female presented with restlessness, tachycardia and vomiting but with normothermia which is an unusual presentation. There is the need for clinicians to be aware of atypical clinical features that can make the diagnosis of thyroid storm difficult.

  8. Normothermic thyroid storm: an unusual presentation.

    PubMed

    Sabir, Anas Ahmad; Sada, Kabiru; Yusuf, Bashir O; Aliyu, Idris

    2016-08-01

    Thyroid storm is a rare life-threatening emergency due to thyrotoxicosis. A 30-year-old female presented with restlessness, tachycardia and vomiting but with normothermia which is an unusual presentation. There is the need for clinicians to be aware of atypical clinical features that can make the diagnosis of thyroid storm difficult. PMID:27540465

  9. The evaluation and management of electrical storm.

    PubMed

    Eifling, Michael; Razavi, Mehdi; Massumi, Ali

    2011-01-01

    Electrical storm is an increasingly common and life-threatening syndrome that is defined by 3 or more sustained episodes of ventricular tachycardia, ventricular fibrillation, or appropriate shocks from an implantable cardioverter-defibrillator within 24 hours. The clinical presentation can be dramatic. Electrical storm can manifest itself during acute myocardial infarction and in patients who have structural heart disease, an implantable cardioverter-defibrillator, or an inherited arrhythmic syndrome. The presence or absence of structural heart disease and the electrocardiographic morphology of the presenting arrhythmia can provide important diagnostic clues into the mechanism of electrical storm. Electrical storm typically has a poor outcome.The effective management of electrical storm requires an understanding of arrhythmia mechanisms, therapeutic options, device programming, and indications for radiofrequency catheter ablation. Initial management involves determining and correcting the underlying ischemia, electrolyte imbalances, or other causative factors. Amiodarone and β-blockers, especially propranolol, effectively resolve arrhythmias in most patients. Nonpharmacologic treatment, including radiofrequency ablation, can control electrical storm in drug-refractory patients. Patients who have implantable cardioverter-defibrillators can present with multiple shocks and may require drug therapy and device reprogramming. After the acute phase of electrical storm, the treatment focus should shift toward maximizing heart-failure therapy, performing revascularization, and preventing subsequent ventricular arrhythmias. Herein, we present an organized approach for effectively evaluating and managing electrical storm.

  10. A Rare Stapes Abnormality

    PubMed Central

    Kanona, Hala; Virk, Jagdeep Singh; Kumar, Gaurav; Chawda, Sanjiv; Khalil, Sherif

    2015-01-01

    The aim of this study is to increase awareness of rare presentations, diagnostic difficulties alongside management of conductive hearing loss and ossicular abnormalities. We report the case of a 13-year-old female reporting progressive left-sided hearing loss and high resolution computed tomography was initially reported as normal. Exploratory tympanotomy revealed an absent stapedius tendon and lack of connection between the stapes superstructure and footplate. The footplate was fixed. Stapedotomy and stapes prosthesis insertion resulted in closure of the air-bone gap by 50 dB. A review of world literature was performed using MedLine. Middle ear ossicular discontinuity can result in significant conductive hearing loss. This can be managed effectively with surgery to help restore hearing. However, some patients may not be suitable or decline surgical intervention and can be managed safely conservatively. PMID:25628909

  11. Interactions Between Convective Storms and Their Environment

    NASA Technical Reports Server (NTRS)

    Maddox, R. A.; Hoxit, L. R.; Chappell, C. F.

    1979-01-01

    The ways in which intense convective storms interact with their environment are considered for a number of specific severe storm situations. A physical model of subcloud wind fields and vertical wind profiles was developed to explain the often observed intensification of convective storms that move along or across thermal boundaries. A number of special, unusually dense, data sets were used to substantiate features of the model. GOES imagery was used in conjunction with objectively analyzed surface wind data to develop a nowcast technique that might be used to identify specific storm cells likely to become tornadic. It was shown that circulations associated with organized meso-alpha and meso-beta scale storm complexes may, on occasion, strongly modify tropospheric thermodynamic patterns and flow fields.

  12. A rare case of thyroid storm.

    PubMed

    McMillen, Brock; Dhillon, Manvinder Shelley; Yong-Yow, Sabrina

    2016-04-18

    Thyroid storm is a rare and life-threatening state of thyroid hormone excess. Rapid recognition of thyroid storm is key to decreasing the morbidity and mortality of this condition. Clinical manifestations of thyroid storm include unexplained weight loss, hyperactivity and irritability. The most common causes of thyrotoxicosis are Graves' disease, toxic multinodular goitre and toxic adenoma. We present a rare case of thyroid storm induced by dual nivolumab and ipilimumab immunotherapy in a patient receiving treatment for advanced melanoma. In this case, our patient was admitted for thyroid storm 1 month after initiating treatment with nivolumab and ipilimumab immunotherapy. The patient was treated with β-blockers, antithyroid medications and systemic steroids resulting in an improvement in thyroid function testing and symptoms.

  13. Effects of the magnetic storm in April 2000 in the low latitude ionosphere near longitude 120E

    NASA Astrophysics Data System (ADS)

    Liu, L.; Wan, W.; Lee, C.

    A halo-CME induced interplanetary shock wave that passed the Earth around 1648 UT on April 6, 2000 triggered a geomagnetic storm with a minimum value of about -300 nT in Dst index. In this paper, digisonde data from ionospheric stations at Chungli, Wuhan, and Kokubunji are included to investigate the ionospheric responses of low latitudes near longitude 120 E to this storm. At three low latitudes near longitude 120 E during this storm, the significant ionospheric responses was an anomalous rapid and large increase in the ionospheric heights occurred around the beginning of the main phase, and the lifts in h'F and hmF2 lasted for about 2 hours. The nearsimultaneous ionosphere increase was also observed at Chungli, Taiwan. And a wave like disturbance appeared on daytime of the second day. The near simultaneity of the ionospheric lifts at these stations in the nighttime ionospheric heights after the SSC suggested that an ExB plasma drift due to the storm related perturbed east-west electric fields. The empirical models of storm time equatorial zonal electric fields (Fejer and Scherliess, 1997) attributed those rapid and large lifts to the effect of solar wind-magnetosphere dynamo origin, which penetrate to low latitudes and equatorial regions. The following wave like disturbance was suggested to be caused by storm induced Travelling atmospheric disturbances (TADs). A method developed by Liu et al. (2002) and Luan et al. (2002) was used to derive the vertical effective winds from ionospheric measurements. It also shows that there was a significantly downward and upward vertical drift during the storm, which verifies the existence of the storm related perturbed east-west electric fields. Finally, the ionospheric storm time derivation from its monthly median level at these stations was also used to validate the predication ability of STORM, a storm empirical model of Araujo-Pradere et al. (2001), which is now included in the international reference ionosphere model IRI

  14. The influence of mid-latitude storm tracks on hot, cold, dry and wet extremes.

    PubMed

    Lehmann, Jascha; Coumou, Dim

    2015-01-01

    Changes in mid-latitude circulation can strongly affect the number and intensity of extreme weather events. In particular, high-amplitude quasi-stationary planetary waves have been linked to prolonged weather extremes at the surface. In contrast, analyses of fast-traveling synoptic-scale waves and their direct influence on heat and cold extremes are scarce though changes in such waves have been detected and are projected for the 21st century. Here we apply regression analyses of synoptic activity with surface temperature and precipitation in monthly gridded observational data. We show that over large parts of mid-latitude continental regions, summer heat extremes are associated with low storm track activity. In winter, the occurrence of cold spells is related to low storm track activity over parts of eastern North America, Europe, and central- to eastern Asia. Storm tracks thus have a moderating effect on continental temperatures. Pronounced storm track activity favors monthly rainfall extremes throughout the year, whereas dry spells are associated with a lack thereof. Trend analyses reveal significant regional changes in recent decades favoring the occurrence of cold spells in the eastern US, droughts in California and heat extremes over Eurasia. PMID:26657163

  15. The influence of mid-latitude storm tracks on hot, cold, dry and wet extremes

    PubMed Central

    Lehmann, Jascha; Coumou, Dim

    2015-01-01

    Changes in mid-latitude circulation can strongly affect the number and intensity of extreme weather events. In particular, high-amplitude quasi-stationary planetary waves have been linked to prolonged weather extremes at the surface. In contrast, analyses of fast-traveling synoptic-scale waves and their direct influence on heat and cold extremes are scarce though changes in such waves have been detected and are projected for the 21st century. Here we apply regression analyses of synoptic activity with surface temperature and precipitation in monthly gridded observational data. We show that over large parts of mid-latitude continental regions, summer heat extremes are associated with low storm track activity. In winter, the occurrence of cold spells is related to low storm track activity over parts of eastern North America, Europe, and central- to eastern Asia. Storm tracks thus have a moderating effect on continental temperatures. Pronounced storm track activity favors monthly rainfall extremes throughout the year, whereas dry spells are associated with a lack thereof. Trend analyses reveal significant regional changes in recent decades favoring the occurrence of cold spells in the eastern US, droughts in California and heat extremes over Eurasia. PMID:26657163

  16. The influence of mid-latitude storm tracks on hot, cold, dry and wet extremes.

    PubMed

    Lehmann, Jascha; Coumou, Dim

    2015-12-11

    Changes in mid-latitude circulation can strongly affect the number and intensity of extreme weather events. In particular, high-amplitude quasi-stationary planetary waves have been linked to prolonged weather extremes at the surface. In contrast, analyses of fast-traveling synoptic-scale waves and their direct influence on heat and cold extremes are scarce though changes in such waves have been detected and are projected for the 21st century. Here we apply regression analyses of synoptic activity with surface temperature and precipitation in monthly gridded observational data. We show that over large parts of mid-latitude continental regions, summer heat extremes are associated with low storm track activity. In winter, the occurrence of cold spells is related to low storm track activity over parts of eastern North America, Europe, and central- to eastern Asia. Storm tracks thus have a moderating effect on continental temperatures. Pronounced storm track activity favors monthly rainfall extremes throughout the year, whereas dry spells are associated with a lack thereof. Trend analyses reveal significant regional changes in recent decades favoring the occurrence of cold spells in the eastern US, droughts in California and heat extremes over Eurasia.

  17. Advantages and limitations - A micropaleo approach for tsunamis and storms

    NASA Astrophysics Data System (ADS)

    Hawkes, A. D.

    2012-12-01

    The instrumental and historical records of tsunamis and storms are too short to fully capture the spatial range and temporal occurrence of these rare but often extremely destructive events. One means to assess their likelihood is to develop pre-historic records (paleotsunami and paleotempestology) that detail their imprint on the coastal zone to assess future risk and potentially reduce socio-economic impacts. Studying modern event deposits enables us to deduce what types of characteristics may be retained within the sediment record and how we may use them to reconstruct past events. The use of micropaleontology in event recognition has been used for decades to signify the transport of offshore sediment landward. More detailed analyses are emerging which make use of the offshore distribution of foraminifera and ostracoda to provide insight on wave excavation depth (depth of closure) which could be used to distinguish differing magnitude events. Furthermore, foraminifera, diatoms and pollen have also been used to identify deposits signifying wave run-up and backwash. However, there are a number of limitations to these types of analyses (presence, preservation, analogues, etc) as well as those that hamper all proxies for event recognition (sites, preservation, etc). A suite of examples (multiple researchers, sites and events) will be presented which highlight the advantages and limitations of using a micropaleo approach when analyzing tsunami and storm deposits.

  18. Particle Energization During Magnetic Storms with Steady Magnetospheric Convection

    NASA Astrophysics Data System (ADS)

    Kissinger, J.; Kepko, L.; Baker, D. N.; Kanekal, S. G.; Li, W.; McPherron, R. L.; Angelopoulos, V.

    2013-12-01

    Relativistic electrons pose a space weather hazard to satellites in the radiation belts. Although about half of all geomagnetic storms result in relativistic electron flux enhancements, other storms decrease relativistic electron flux, even under similar solar wind drivers. Radiation belt fluxes depend on a complex balance between transport, loss, and acceleration. A critically important aspect of radiation belt enhancements is the role of the 'seed' population--plasma sheet particles heated and transported Earthward by magnetotail processes--which can become accelerated by wave-particle interactions with chorus waves. While the effect of substorms on seed electron injections has received considerable focus, in this study we explore how quasi-steady convection during steady magnetospheric convection (SMC) events affects the transport and energization of electrons. SMC events are long-duration intervals of enhanced convection without any substorm expansions, and are an important mechanism in coupling magnetotail plasma populations to the inner magnetosphere. We detail the behavior of the seed electron population for stormtime SMC events using the Van Allen Probes in the outer radiation belt and THEMIS in the plasma sheet and inner magnetosphere. Together, the two missions provide the ability to track particle transport and energization from the plasma sheet into the radiation belts. We present SMC events with Van Allen Probes/THEMIS conjunctions and compare plasma sheet fast flows/enhanced transport to radiation belt seed electron enhancements. Finally we utilize statistical analyses to quantify the relative importance of SMC events on radiation belt electron acceleration in comparison to isolated substorms.

  19. The Wave Carpet: An Omnidirectional and Broadband Wave Energy Converter

    NASA Astrophysics Data System (ADS)

    Alam, M.-Reza

    2015-11-01

    Inspired by the strong attenuation of ocean surface waves by muddy seafloors, we have designed, theoretically investigated the performance, and experimentally tested the ``Wave Carpet:'' a mud-resembling synthetic seabed-mounted mat composed of vertically-acting linear springs and generators that can be used as an efficient wave energy absorption device. The Wave Carpet is completely under the water surface hence imposes minimal danger to boats and the sea life (i.e. no mammal entanglement). It is survivable against the high momentum of storm surges and in fact can perform even better under very energetic (e.g. stormy) sea conditions when most existing wave energy devices are needed to shelter themselves by going into an idle mode. In this talk I will present an overview of analytical results for the linear problem, direct simulation of highly nonlinear wave fields, and results of the experimental wave tank investigation.

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

    NASA Astrophysics Data System (ADS)

    Liu, Huiqing; Xie, Lian

    2009-06-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  2. Testable Predictions for Large-Scale Coastline-Shape Change in Response to Changing Storm Climate

    NASA Astrophysics Data System (ADS)

    Murray, A. B.; Moore, L. J.; McNamara, D.; Brenner, O.; Slott, J.

    2008-12-01

    Recent modeling (Ashton et al. 2001; Ashton and Murray, 2006a) and observations (Ashton and Murray 2006b) suggest that sandy coastlines self-organize into large-scale, plan-view shapes that depend sensitively on the regional wave climate-the distribution of influences on alongshore sediment transport from different deep-water wave-approach angles. Subsequent modeling (Slott et al., 2007) shows that even moderate changes in wave climate, as are likely to arise as storm behaviors shift in the coming century, will cause coastlines to change shape rapidly, compared to a steady-wave-climate scenario. Such large-scale shape changes involve greatly accentuated rates of local erosion, and highly variable erosion/accretion rates. A recent analysis of wave records from the Southeastern US (Komar and Allen, 2007) indicates that wave climates have already been changing over the past three decades; the heights of waves attributable to tropical storms have been increasing, changing the angular distribution of wave influences. Modeling based on these observations leads to predictions of how coastlines in this region should already be changing shape (McNamara et al., in prep.). As a case study, we are examining historical shorelines for the Carolina coastline, to test whether the predicted alongshore patterns of shoreline change can already be detected.

  3. Extreme Waves at Filyos, Southern Black Sea

    NASA Astrophysics Data System (ADS)

    Bilyay, Engin; Oztunali Ozbahceci, Berguzar; Cevdet Yalciner, Ahmet

    2010-05-01

    The Ministry of Transport, General Directorate of Railways, Ports and Airports Construction which is responsible for the design and construction of ports and harbors in Turkey, carried out a wave measurement project for a new planned port in Filyos, Western Black Sea region of Turkey. The wave measurement project at Filyos lasted for a period of two years. A self-recording pressure type instrument was used to conduct the wave measurements. Directional information of both waves and current was determined according to an electromagnetic system. The instrument was installed at a depth of 12.5m. Wave data were sampled every two hours with a sample length of 20 minutes and a sampling interval of 0.5 sec (i.e. a sampling frequency of 2 Hz). Before any further wave data analysis, the recorded subsurface pressure data was converted into the corresponding surface profile data. Then individual waves were obtained by zero-up crossing method. The characteristic waves like maximum, Hmax, significant, Hs, one-tenth, H1-10, mean wave height Hmean and the corresponding wave periods were calculated by using individual waves of each record. The analysis results show that the maximum significant wave height during the measurement period is 5.0 m. The maximum wave height is 7.5m in this record which makes the ratio of Hmax/Hs =1.5. The relation between the Hmax and Hs was investigated through a linear regression and the ratios for chosen 14 storms among the whole record were found to change between 1.38 and 1.88. It is stated that the ratio of Hmax / Hs is between 1.6 and 2 in the deep water but it decreases to 1.3 through to shallower zones (Goda, 2000). Since the measurement depth in Filyos is 12.5 m which is an intermediate depth, the result can be expected. However; it was noticed during the analysis that there are records in which Hmax /Hs ratio is higher than 2.0. These higher waves in a record are called as extreme waves using the abnormality index (AI) of Kharif et al. (2009

  4. Storm Surge Modelling of Super Typhoon Haiyan Event in Tacloban City, Leyte using MIKE 21 Model

    NASA Astrophysics Data System (ADS)

    Prelligera, Flor Angel; Caro, Carl Vincent; Ladiero, Christine; Mahar Francisco Lagmay, Alfredo; Lapidez, John Phillip; Malano, Vicente; Agaton, Rojelee; Santiago, Joy; Suarez, John Kenneth

    2014-05-01

    Super Typhoon Haiyan hit the Philippines on 08 November 2013 causing massive destruction to the central part of the country. Arguably the strongest tropical cyclone to make landfall in recorded history, Haiyan caused 6,201 deaths and damages amounting to PhP 36,690,882,497.27 (USD 824,390,091.77). The typhoon also brought about destructive storm surges reaching up to 7 meters in height. A better understanding of storm surge is essential to the development of mechanisms to mitigate the effects of similar events. Thus, a computer simulation of Haiyan with the resulting wave heights and storm surge levels was made using MIKE 21 model -- a software used for many different coastal and marine engineering projects worldwide. Simulations were made using the Hydrodynamic Flexible Mesh (HD FM) model coupled with the Spectral Wave (SW) model of the software. This coupled approach allows accurate calculations of both surge water levels and wave crest heights for overtopping of coastal structures. The maximum mesh flexibility of MIKE 21 allows mesh refinement for the coastal areas of Tacloban City within coarser mesh elements resulting to higher grid accuracy. Input parameters for the simulations of the coastline of Tacloban City, a densely populated coastal community heaviest hit by the storm surges of Haiyan, were obtained from the Philippine Atmospheric, Geophysical, and Astronomical Services Administration (PAGASA) and Japan Meteorological Agency (JMA). Atmospheric conditions such as wind and pressure values were input to a set of regional and local hydrodynamic and spectral wave models. Simulation results were compared with available tidal gauge records and the comparison showed good correlation. Coastal regional inundation maps were then created from the results of the storm surge simulations. These maps or its equivalent should be used to develop and further improve disaster risk management plans for future surge events. These plans include, but are not limited to

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  6. Stability of subsea pipelines during large storms

    PubMed Central

    Draper, Scott; An, Hongwei; Cheng, Liang; White, David J.; Griffiths, Terry

    2015-01-01

    On-bottom stability design of subsea pipelines transporting hydrocarbons is important to ensure safety and reliability but is challenging to achieve in the onerous metocean (meteorological and oceanographic) conditions typical of large storms (such as tropical cyclones, hurricanes or typhoons). This challenge is increased by the fact that industry design guidelines presently give no guidance on how to incorporate the potential benefits of seabed mobility, which can lead to lowering and self-burial of the pipeline on a sandy seabed. In this paper, we demonstrate recent advances in experimental modelling of pipeline scour and present results investigating how pipeline stability can change in a large storm. An emphasis is placed on the initial development of the storm, where scour is inevitable on an erodible bed as the storm velocities build up to peak conditions. During this initial development, we compare the rate at which peak near-bed velocities increase in a large storm (typically less than 10−3 m s−2) to the rate at which a pipeline scours and subsequently lowers (which is dependent not only on the storm velocities, but also on the mechanism of lowering and the pipeline properties). We show that the relative magnitude of these rates influences pipeline embedment during a storm and the stability of the pipeline. PMID:25512592

  7. Stability of subsea pipelines during large storms.

    PubMed

    Draper, Scott; An, Hongwei; Cheng, Liang; White, David J; Griffiths, Terry

    2015-01-28

    On-bottom stability design of subsea pipelines transporting hydrocarbons is important to ensure safety and reliability but is challenging to achieve in the onerous metocean (meteorological and oceanographic) conditions typical of large storms (such as tropical cyclones, hurricanes or typhoons). This challenge is increased by the fact that industry design guidelines presently give no guidance on how to incorporate the potential benefits of seabed mobility, which can lead to lowering and self-burial of the pipeline on a sandy seabed. In this paper, we demonstrate recent advances in experimental modelling of pipeline scour and present results investigating how pipeline stability can change in a large storm. An emphasis is placed on the initial development of the storm, where scour is inevitable on an erodible bed as the storm velocities build up to peak conditions. During this initial development, we compare the rate at which peak near-bed velocities increase in a large storm (typically less than 10(-3) m s(-2)) to the rate at which a pipeline scours and subsequently lowers (which is dependent not only on the storm velocities, but also on the mechanism of lowering and the pipeline properties). We show that the relative magnitude of these rates influences pipeline embedment during a storm and the stability of the pipeline.

  8. long duration dust storm sequences on Mars

    NASA Astrophysics Data System (ADS)

    Wang, H.

    2012-12-01

    The Mars Global Surveyor (MGS) Mars Observer Camera (MOC) and Mars Reconnaissance Orbiter (MRO) Mars Color Imager (MARCI) Mars daily global maps have revealed new characteristics for long duration dust storm sequences. These dust storm sequences have long histories of more than a week, travel long distances out of their origination region, and influence large areas in different regions of the planet. During the Ls = 180 - 360 season, except for global dust storms which involve multiple remote dust lifting centers and generally expand explosively from the southern hemisphere northward, other long-lived dust storm sequences usually travel southward through the Acidalia-Chryse, Utopia-Isidis or Arcadia-Amazonis channels with subsequent dust lifting along the way. Sometimes, they penetrate remarkably deep to the southern high latitudes, producing fantastic display of dust band. During the rest of the year, long duration dust storm sequences usually originate from the Argyre/Solis, Hellas/Noachis, or Cimmeria/Sirenum area and travel northward toward the southern low latitudes. Each route exhibits its own peculiar characteristics. We will present our results about these long duration dust storm sequences summarized from the complete archive of MGS MOC daily global maps and two years of MRO MARCI daily global maps. The systematic daily nearly global coverage of these maps makes it feasible to reconstruct the history of long duration dust storm sequences with detail.

  9. Ictal Cardiac Ryhthym Abnormalities

    PubMed Central

    Ali, Rushna

    2016-01-01

    Cardiac rhythm abnormalities in the context of epilepsy are a well-known phenomenon. However, they are under-recognized and often missed. The pathophysiology of these events is unclear. Bradycardia and asystole are preceded by seizure onset suggesting ictal propagation into the cortex impacting cardiac autonomic function, and the insula and amygdala being possible culprits. Sudden unexpected death in epilepsy (SUDEP) refers to the unanticipated death of a patient with epilepsy not related to status epilepticus, trauma, drowning, or suicide. Frequent refractory generalized tonic-clonic seizures, anti-epileptic polytherapy, and prolonged duration of epilepsy are some of the commonly identified risk factors for SUDEP. However, the most consistent risk factor out of these is an increased frequency of generalized tonic–clonic seizures (GTC). Prevention of SUDEP is extremely important in patients with chronic, generalized epilepsy. Since increased frequency of GTCS is the most consistently reported risk factor for SUDEP, effective seizure control is the most important preventive strategy. PMID:27347227

  10. Ictal Cardiac Ryhthym Abnormalities.

    PubMed

    Ali, Rushna

    2016-01-01

    Cardiac rhythm abnormalities in the context of epilepsy are a well-known phenomenon. However, they are under-recognized and often missed. The pathophysiology of these events is unclear. Bradycardia and asystole are preceded by seizure onset suggesting ictal propagation into the cortex impacting cardiac autonomic function, and the insula and amygdala being possible culprits. Sudden unexpected death in epilepsy (SUDEP) refers to the unanticipated death of a patient with epilepsy not related to status epilepticus, trauma, drowning, or suicide. Frequent refractory generalized tonic-clonic seizures, anti-epileptic polytherapy, and prolonged duration of epilepsy are some of the commonly identified risk factors for SUDEP. However, the most consistent risk factor out of these is an increased frequency of generalized tonic-clonic seizures (GTC). Prevention of SUDEP is extremely important in patients with chronic, generalized epilepsy. Since increased frequency of GTCS is the most consistently reported risk factor for SUDEP, effective seizure control is the most important preventive strategy. PMID:27347227

  11. Communication and abnormal behaviour.

    PubMed

    Crown, S

    1979-01-01

    In this paper the similarities between normal and abnormal behaviour are emphasized and selected aspects of communication, normal and aberrant, between persons are explored. Communication in a social system may be verbal or non-verbal: one person's actions cause a response in another person. This response may be cognitive, behavioural or physiological. Communication may be approached through the individual, the social situation or social interaction. Psychoanalysis approaches the individual in terms of the coded communications of psychoneurotic symptoms or psychotic behaviour; the humanist-existential approach is concerned more with emotional expression. Both approaches emphasize the development of individual identity. The interaction between persons and their social background is stressed. Relevant are sociological concepts such as illness behaviour, stigma, labelling, institutionalization and compliance. Two approaches to social interactions are considered: the gamesplaying metaphor, e.g. back pain as a psychosocial manipulation--the 'pain game'; and the 'spiral of reciprocal perspectives' which emphasizes the interactional complexities of social perceptions. Communicatory aspects of psychological treatments are noted: learning a particular metaphor such as 'resolution' of the problem (psychotherapy), learning more 'rewarding' behaviour (learning theory) or learning authenticity or self-actualization (humanist-existential).

  12. Communication and abnormal behaviour.

    PubMed

    Crown, S

    1979-01-01

    In this paper the similarities between normal and abnormal behaviour are emphasized and selected aspects of communication, normal and aberrant, between persons are explored. Communication in a social system may be verbal or non-verbal: one person's actions cause a response in another person. This response may be cognitive, behavioural or physiological. Communication may be approached through the individual, the social situation or social interaction. Psychoanalysis approaches the individual in terms of the coded communications of psychoneurotic symptoms or psychotic behaviour; the humanist-existential approach is concerned more with emotional expression. Both approaches emphasize the development of individual identity. The interaction between persons and their social background is stressed. Relevant are sociological concepts such as illness behaviour, stigma, labelling, institutionalization and compliance. Two approaches to social interactions are considered: the gamesplaying metaphor, e.g. back pain as a psychosocial manipulation--the 'pain game'; and the 'spiral of reciprocal perspectives' which emphasizes the interactional complexities of social perceptions. Communicatory aspects of psychological treatments are noted: learning a particular metaphor such as 'resolution' of the problem (psychotherapy), learning more 'rewarding' behaviour (learning theory) or learning authenticity or self-actualization (humanist-existential). PMID:261653

  13. Abnormal uterine bleeding.

    PubMed

    Whitaker, Lucy; Critchley, Hilary O D

    2016-07-01

    Abnormal uterine bleeding (AUB) is a common and debilitating condition with high direct and indirect costs. AUB frequently co-exists with fibroids, but the relationship between the two remains incompletely understood and in many women the identification of fibroids may be incidental to a menstrual bleeding complaint. A structured approach for establishing the cause using the Fédération International de Gynécologie et d'Obstétrique (FIGO) PALM-COEIN (Polyp, Adenomyosis, Leiomyoma, Malignancy (and hyperplasia), Coagulopathy, Ovulatory disorders, Endometrial, Iatrogenic and Not otherwise classified) classification system will facilitate accurate diagnosis and inform treatment options. Office hysteroscopy and increasing sophisticated imaging will assist provision of robust evidence for the underlying cause. Increased availability of medical options has expanded the choice for women and many will no longer need to recourse to potentially complicated surgery. Treatment must remain individualised and encompass the impact of pressure symptoms, desire for retention of fertility and contraceptive needs, as well as address the management of AUB in order to achieve improved quality of life. PMID:26803558

  14. Abortion for fetal abnormality.

    PubMed

    Maclean, N E

    1979-07-25

    I wish to thank Dr. Pauline Bennett for her reply (NZ Med J, 13 June). She has demonstrated well that in dealing with sensitive difficult issues such as abortion for fetal abnormality, the one thing the doctor is not recommended to do is to speak the truth] I am prompted to write this letter for 2 reasons. Firstly, the excellent letter written by Dr. A. M. Rutherford (NZ Med J, 13 June) on the subject of abortion stated, "The most disturbing feature about the whole controversy is the 'blunting of our conscience'." When the doctors are not encouraged to be honest with patients then indeed our conscience has been blunted. Secondly, I watched Holocaust last night, and cannot refrain from stating that I see frightening parallels between our liberal abortion policy and the activities of the Nazis. As I watched the "mental patients" being herded into the shed for gassing by the polite, tidy, white coated medical staff, and then heard the compassionate, sensitive, letter of the hospital authorities to the relatives of the deceased, the parallel became obvious. The mental patients were weak, defenseless, burdensome, and uneconomic; the unborn are weak, defenseless, burdensome, and uneconomic. The hospital authority's letter was acceptable in many ways, acceptable except that its words bore no relation to the truth. It is said that the "first casualty of war is the truth". Whether that war involves the Jews, or the insane, or the unborn, the statement would seem correct.

  15. Tropical cyclone waves detected with infrasound sensor array

    NASA Astrophysics Data System (ADS)

    Schultz, Colin

    2013-02-01

    The strong winds of a tropical cyclone whip up the sea surface, driving ocean waves a dozen meters high. When one such ocean wave runs into another wave that has an equal period but is traveling in the opposite direction, the interaction produces low-frequency sound waves that can be detected thousands of kilometers away. The infrasound signals produced by interacting ocean surface waves—known as microbarom—have typical frequencies around 0.2 hertz. Researchers previously determined that as a hurricane travels along its track, early waves generated by the storm will interact with those generated later on, producing a strong microbarom signal in the storm's wake. Researchers also found, however, that microbarom signals are produced by regular surface ocean behavior, including swell, surface waves, and nontropical cyclone storms.

  16. Ionspheric and thermospheric response to the 27-28 February 2014 geomagnetic storm

    NASA Astrophysics Data System (ADS)

    Khalifa, Malki; Benkhaldoun, Zouhair; Vilmer, Nicole; Bounhir, Aziza; Makela, Jonathan J.; Kaab, Mohamed; Lagheryeb, Amine

    2015-08-01

    The present work explores the ionospheric and thermospheric responses to the 27-28 February 2014 geomagnetic storm. This storm was consecutive to CME associated flares that occurred on 25 February. A Fabry Perrot interferometer provides measurements of the neutral winds and temperature based on the observations of the 630 nm redline emission and of a wide angle imaging system which records images of the 630 nm emission.The effects of this geomagnetic storm on the thermosphere are evident from the clear departure of the winds and the temperature from their seasonal behavior. The effects on the ionosphere were also evident through the change observed in the background electric field as shown from the plasma bubbles drifts direction reversal. Attention was paid to the the interplanetary medium ; solar wind, interplanetary magnetic field, shock waves and geomagnetic indices. We also explore RHESSI data of the flare.

  17. Inverse modeling of storm intensity based on grain-size analysis of hurricane-induced event beds

    NASA Astrophysics Data System (ADS)

    Castagno, K. A.; Donnelly, J. P.

    2015-12-01

    As the coastal population continues to grow in size and wealth, increased hurricane frequency and intensity present a growing threat of property damage and loss of life. Recent reconstructions of past intense-hurricane landfalls from sediment cores in southeastern New England identify a series of active intervals over the past 2,000 years, with the last few centuries among the most quiescent intervals. The frequency of intense-hurricane landfalls in southeastern New England is well constrained, but the intensity of these storms, particularly prehistoric events, is not. This study analyzes the grain sizes of major storm event beds along a transect of sediment cores in Salt Pond, Falmouth, MA. Several prehistoric events contain more coarse material than any of the deposits from the historical interval, suggesting that landfalling hurricanes in the northeastern United States may have been more intense than the historically encountered category 2 and 3 storms. The intensity of major storm events is estimated using grain-size analysis with a digital image processing, size, and shape analyzer. Since event deposits in Salt Pond result from a combination of coastal inundation and wave action, a large population of both historical and synthetic storms is used to assess the storm characteristics that could result in the wave heights inversely modeled from grain size trends. Intense-hurricane activity may be closely tied to warming in sea surface temperature. As such, the prehistoric intervals of increased frequency and intensity provide potential analogs for current and future hurricane risk in the northeastern United States.

  18. Interplanetary shock waves associated with solar flares

    NASA Technical Reports Server (NTRS)

    Chao, J. K.; Sakurai, K.

    1974-01-01

    The interaction of the earth's magnetic field with the solar wind is discussed with emphasis on the influence of solar flares. The geomagnetic storms are considerered to be the result of the arrival of shock wave generated by solar flares in interplanetary space. Basic processes in the solar atmosphere and interplanetary space, and hydromagnetic disturbances associated with the solar flares are discussed along with observational and theoretical problems of interplanetary shock waves. The origin of interplanetary shock waves is also discussed.

  19. Measured winter performance of storm windows

    SciTech Connect

    Klems, Joseph H.

    2002-08-23

    Direct comparison measurements were made between various prime/storm window combinations and a well-weatherstripped, single-hung replacement window with a low-E selective glazing. Measurements were made using an accurate outdoor calorimetric facility with the windows facing north. The doublehung prime window was made intentionally leaky. Nevertheless, heat flows due to air infiltration were found to be small, and performance of the prime/storm combinations was approximately what would be expected from calculations that neglect air infiltration. Prime/low-E storm window combinations performed very similarly to the replacement window. Interestingly, solar heat gain was not negligible, even in north-facing orientation.

  20. Lightning activity and severe storm structure

    NASA Technical Reports Server (NTRS)

    Taylor, W. L.; Brandes, E. A.; Rust, W. D.; Macgorman, D. R.

    1984-01-01

    Space-time mapping of VHF sources from four severe storms on June 19, 1980 reveals that lightning processes for cloud-to-ground (CG) and large intracloud (IC) flashes are confined to an altitude below about 10 km and closely associated with the central regions of high reflectivity. Another class of IC flashes produces a splattering of sources within the storms' main electrically active volumes and also within the large divergent wind canopy aloft. There is no apparent temporal association between the small high altitude IC flashes that occur almost continuously and the large IC and CG flashes that occur sporadically in the lower portions of storms.

  1. Storm-induced sea-ice breakup and the implications for ice extent.

    PubMed

    Kohout, A L; Williams, M J M; Dean, S M; Meylan, M H

    2014-05-29

    The propagation of large, storm-generated waves through sea ice has so far not been measured, limiting our understanding of how ocean waves break sea ice. Without improved knowledge of ice breakup, we are unable to understand recent changes, or predict future changes, in Arctic and Antarctic sea ice. Here we show that storm-generated ocean waves propagating through Antarctic sea ice are able to transport enough energy to break sea ice hundreds of kilometres from the ice edge. Our results, which are based on concurrent observations at multiple locations, establish that large waves break sea ice much farther from the ice edge than would be predicted by the commonly assumed exponential decay. We observed the wave height decay to be almost linear for large waves--those with a significant wave height greater than three metres--and to be exponential only for small waves. This implies a more prominent role for large ocean waves in sea-ice breakup and retreat than previously thought. We examine the wider relevance of this by comparing observed Antarctic sea-ice edge positions with changes in modelled significant wave heights for the Southern Ocean between 1997 and 2009, and find that the retreat and expansion of the sea-ice edge correlate with mean significant wave height increases and decreases, respectively. This includes capturing the spatial variability in sea-ice trends found in the Ross and Amundsen-Bellingshausen seas. Climate models fail to capture recent changes in sea ice in both polar regions. Our results suggest that the incorporation of explicit or parameterized interactions between ocean waves and sea ice may resolve this problem.

  2. Storm-induced sea-ice breakup and the implications for ice extent.

    PubMed

    Kohout, A L; Williams, M J M; Dean, S M; Meylan, M H

    2014-05-29

    The propagation of large, storm-generated waves through sea ice has so far not been measured, limiting our understanding of how ocean waves break sea ice. Without improved knowledge of ice breakup, we are unable to understand recent changes, or predict future changes, in Arctic and Antarctic sea ice. Here we show that storm-generated ocean waves propagating through Antarctic sea ice are able to transport enough energy to break sea ice hundreds of kilometres from the ice edge. Our results, which are based on concurrent observations at multiple locations, establish that large waves break sea ice much farther from the ice edge than would be predicted by the commonly assumed exponential decay. We observed the wave height decay to be almost linear for large waves--those with a significant wave height greater than three metres--and to be exponential only for small waves. This implies a more prominent role for large ocean waves in sea-ice breakup and retreat than previously thought. We examine the wider relevance of this by comparing observed Antarctic sea-ice edge positions with changes in modelled significant wave heights for the Southern Ocean between 1997 and 2009, and find that the retreat and expansion of the sea-ice edge correlate with mean significant wave height increases and decreases, respectively. This includes capturing the spatial variability in sea-ice trends found in the Ross and Amundsen-Bellingshausen seas. Climate models fail to capture recent changes in sea ice in both polar regions. Our results suggest that the incorporation of explicit or parameterized interactions between ocean waves and sea ice may resolve this problem. PMID:24870546

  3. A comparative study of wave-current interactions over the eastern Canadian shelf under severe weather conditions using a coupled wave-circulation model

    NASA Astrophysics Data System (ADS)

    Wang, Pengcheng; Sheng, Jinyu

    2016-07-01

    A coupled wave-circulation model is used to examine interactions between surface gravity waves and ocean currents over the eastern Canadian shelf and adjacent deep waters during three severe weather events. The simulated significant wave heights (SWHs) and peak wave periods reveal the importance of wave-current interactions (WCI) during and after the storm. In two fast-moving hurricane cases, the maximum SWHs are reduced by more than 11% on the right-hand side of the storm track and increased by about 5% on the left-hand side due to different WCI mechanisms on waves on two sides of the track. The dominate mechanisms of the WCI on waves include the current-induced modification of wind energy input to the wave generation, and current-induced wave advection and refraction. In the slow-moving winter storm case, the effect of WCI decreases the maximum SWHs on both sides of the storm track due to different results of the current-induced wave advection, which is affected greatly by the storm translation speed. The simulated sea surface temperature (SST) cooling induced by hurricanes and SST warming induced by the winter storm are also enhanced (up to 1.2°C) by the WCI mechanisms on circulation and hydrography. The 3D wave forces can affect water columns up to 200 m in all three storm cases. By comparison, the effect of breaking wave-induced mixing in the ocean upper layer is more important under strong stratification conditions in two hurricane cases than under weak stratification conditions in the winter storm case.

  4. Relativistic electron acceleration during HILDCAA events: are precursor CIR magnetic storms important?

    NASA Astrophysics Data System (ADS)

    Hajra, Rajkumar; Tsurutani, Bruce T.; Echer, Ezequiel; Gonzalez, Walter D.; Brum, Christiano Garnett Marques; Vieira, Luis Eduardo Antunes; Santolik, Ondrej

    2015-07-01

    We present a comparative study of high-intensity long-duration continuous AE activity (HILDCAA) events, both isolated and those occurring in the "recovery phase" of geomagnetic storms induced by corotating interaction regions (CIRs). The aim of this study is to determine the difference, if any, in relativistic electron acceleration and magnetospheric energy deposition. All HILDCAA events in solar cycle 23 (from 1995 through 2008) are used in this study. Isolated HILDCAA events are characterized by enhanced fluxes of relativistic electrons compared to the pre-event flux levels. CIR magnetic storms followed by HILDCAA events show almost the same relativistic electron signatures. Cluster 1 spacecraft showed the presence of intense whistler-mode chorus waves in the outer magnetosphere during all HILDCAA intervals (when Cluster data were available). The storm-related HILDCAA events are characterized by slightly lower solar wind input energy and larger magnetospheric/ionospheric dissipation energy compared with the isolated events. A quantitative assessment shows that the mean ring current dissipation is ~34 % higher for the storm-related events relative to the isolated events, whereas Joule heating and auroral precipitation display no (statistically) distinguishable differences. On the average, the isolated events are found to be comparatively weaker and shorter than the storm-related events, although the geomagnetic characteristics of both classes of events bear no statistically significant difference. It is concluded that the CIR storms preceding the HILDCAAs have little to do with the acceleration of relativistic electrons. Our hypothesis is that ~10-100-keV electrons are sporadically injected into the magnetosphere during HILDCAA events, the anisotropic electrons continuously generate electromagnetic chorus plasma waves, and the chorus then continuously accelerates the high-energy portion of this electron spectrum to MeV energies.

  5. How frequent is storm-induced flooding in the central part of the Bay of Biscay?

    NASA Astrophysics Data System (ADS)

    Breilh, Jean-François; Bertin, Xavier; Chaumillon, Éric; Giloy, Nathalie; Sauzeau, Thierry

    2014-11-01

    This study analyzes historical archives to produce a database of storm-induced coastal flooding in the French central part of the Bay of Biscay since 1500 AD. From this new database, 46 coastal floods have been reported for the last 500 years (1 event every 11 yr on average), which demonstrates the high vulnerability of this region to coastal flooding. The limitations of historical archives prevent concluding to a change in storminess over the period. The six largest coastal floods that occurred since 1900 are further investigated because numerous informations are available in terms of meteorological conditions as well as maximum water levels reached. Associated storm surges are also modeled using a simplified methodology, relying on a fully coupled wave and circulation modeling system directly forced by the available meteorological data. The analysis of modeling results and historical archives reveals firstly that several meteo-oceanic settings can lead to extensive coastal flooding in the studied area. The analyzed events allow distinguishing three main settings: (1) a small storm surge associated with the highest astronomical tidal levels, (2) a large storm surge, induced either by extreme winds or a particular sea-state and associated with high astronomical tidal levels and, (3) a large storm surge enhanced by extreme wave conditions. Second, maximum water levels reached during these 6 coastal floods were shown to be higher than the 100 years return period water level estimated in several recently published studies. This inconstancy can be explained mainly by the lack of extreme water level records in tide gauge datasets used in these previous studies. To a slightest degree, this study questions the validity of classical statistical approaches when analyzing extreme water levels data resulting from contrasting meteo-oceanic settings. It is concluded that historical archives combined with storm surge modeling could be a valuable approach to better estimate the

  6. Radial diffusion with outer boundary determined by geosynchronous measurements: Storm and post-storm intervals

    NASA Astrophysics Data System (ADS)

    Chu, F.; Haines, P.; Hudson, M.; Kress, B.; Freidel, R.; Kanekal, S.

    2007-12-01

    Work is underway by several groups to quantify diffusive radial transport of radiation belt electrons, including a model for pitch angle scattering losses to the atmosphere. The radial diffusion model conserves the first and second adiabatic invariants and breaks the third invariant. We have developed a radial diffusion code which uses the Crank Nicholson method with a variable outer boundary condition. For the radial diffusion coefficient, DLL, we have several choices, including the Brautigam and Albert (JGR, 2000) diffusion coefficient parameterized by Kp, which provides an ad hoc measure of the power level at ULF wave frequencies in the range of electron drift (mHz), breaking the third invariant. Other diffusion coefficient models are Kp-independent, fixed in time but explicitly dependent on the first invariant, or energy at a fixed L, such as calculated by Elkington et al. (JGR, 2003) and Perry et al. (JGR, 2006) based on ULF wave model fields. We analyzed three periods of electron flux and phase space density (PSD) enhancements inside of geosynchronous orbit: March 31 - May 31, 1991, and July 2004 and Nov 2004 storm intervals. The radial diffusion calculation is initialized with a computed phase space density profile for the 1991 interval using differential flux values from the CRRES High Energy Electron Fluxmeter instrument, covering 0.65 - 7.5 MeV. To calculate the initial phase space density, we convert Roederer L* to McIlwain's L- parameter using the ONERA-DESP program. A time averaged model developed by Vampola1 from the entire 14 month CRRES data set is applied to the July 2004 and Nov 2004 storms. The online CRESS data for specific orbits and the Vampola-model flux are both expressed in McIlwain L-shell, while conversion to L* conserves phase space density in a distorted non-dipolar magnetic field model. A Tsyganenko (T04) magnetic field model is used for conversion between L* and L. The outer boundary PSD is updated using LANL GEO satellite fluxes

  7. Sensitivity of wind waves to hurricane wind characteristics

    NASA Astrophysics Data System (ADS)

    Liu, Huiqing; Xie, Lian; Pietrafesa, Leonard J.; Bao, Shaowu

    In this study, the influence of the spatial and temporal variability of hurricane winds, storm translation speed, intensity, and ambient wind field on surface wind waves are investigated by using a third-generation wave model (Simulating WAves Nearshore, or SWAN). The results show that the asymmetric structure of wind-induced wave field is sensitive not only to the asymmetric structure of the hurricane wind field, but also to the variations in the storm translation speed and intensity. The significant wave height (SWH) in the front-right quadrant of the storm rises as storm translation speed increases until it reaches a critical value, then the SWH drops. The opposite occurs in the rear-left quadrant. The total contribution of the hurricane translation speed to the asymmetric structure of the wave field also depends on the intensity of the hurricane. As the intensity of the hurricane increases, the relative significance of the influence of the translation speed on the asymmetric structure of the wave field decreases. Most parametric hurricane wind models can only model symmetric hurricanes and do not include background winds. However, actual hurricanes in nature are not only asymmetric but also imbedded in background winds. Thus, to more properly model hurricane-induced wave field, it is important to consider storm asymmetry, translation speed, intensity, as well as background winds.

  8. Haem degradation in abnormal haemoglobins.

    PubMed Central

    Brown, S B; Docherty, J C

    1978-01-01

    The coupled oxidation of certain abnormal haemoglobins leads to different bile-pigment isomer distributions from that of normal haemoglobin. The isomer pattern may be correlated with the structure of the abnormal haemoglobin in the neighbourhood of the haem pocket. This is support for haem degradation by an intramolecular reaction. PMID:708385

  9. Systemic abnormalities in liver disease

    PubMed Central

    Minemura, Masami; Tajiri, Kazuto; Shimizu, Yukihiro

    2009-01-01

    Systemic abnormalities often occur in patients with liver disease. In particular, cardiopulmonary or renal diseases accompanied by advanced liver disease can be serious and may determine the quality of life and prognosis of patients. Therefore, both hepatologists and non-hepatologists should pay attention to such abnormalities in the management of patients with liver diseases. PMID:19554648

  10. Abnormal pressure in hydrocarbon environments

    USGS Publications Warehouse

    Law, B.E.; Spencer, C.W.

    1998-01-01

    Abnormal pressures, pressures above or below hydrostatic pressures, occur on all continents in a wide range of geological conditions. According to a survey of published literature on abnormal pressures, compaction disequilibrium and hydrocarbon generation are the two most commonly cited causes of abnormally high pressure in petroleum provinces. In young (Tertiary) deltaic sequences, compaction disequilibrium is the dominant cause of abnormal pressure. In older (pre-Tertiary) lithified rocks, hydrocarbon generation, aquathermal expansion, and tectonics are most often cited as the causes of abnormal pressure. The association of abnormal pressures with hydrocarbon accumulations is statistically significant. Within abnormally pressured reservoirs, empirical evidence indicates that the bulk of economically recoverable oil and gas occurs in reservoirs with pressure gradients less than 0.75 psi/ft (17.4 kPa/m) and there is very little production potential from reservoirs that exceed 0.85 psi/ft (19.6 kPa/m). Abnormally pressured rocks are also commonly associated with unconventional gas accumulations where the pressuring phase is gas of either a thermal or microbial origin. In underpressured, thermally mature rocks, the affected reservoirs have most often experienced a significant cooling history and probably evolved from an originally overpressured system.

  11. Electrocardiograph abnormalities revealed during laparoscopy.

    PubMed

    Nijjer, Sukhjinder; Dubrey, Simon William

    2010-01-01

    This brief case presents a well patient in whom an electrocardiograph abnormality consistent with an accessory pathway was found during a routine procedure. We present the electrocardiographs, explain the underlying condition, and consider why the abnormality was revealed in this manner.

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

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-08-01

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

  14. Unraveling Local Dust Storm Structure on Mars: The Case of Northern Amazonis During Mars Year 24

    NASA Astrophysics Data System (ADS)

    Heavens, N. G.

    2015-12-01

    On an average Martian afternoon, two or three local dust storms are taking place somewhere on the planet. By definition, these storms range in area from a few square kilometers to hundreds of thousands, rarely surviving from sol to the next. After more than 40 years of observation, a great deal is known about where and when they occur, but very little is known about the structure and dynamics of individual storms. This contrast in our knowledge about local dust storms results from how they are observed. Daily global mapping of Mars in the visible has enabled an accurate census of storms as well as observation of their morphological diversity. However, even under ideal conditions, an individual storm is only observed by sounder-type instrumentation once or twice (if it is a large enough), providing an incomplete picture of structure of an individual storm. Early studies of cyclogenesis on Earth had a similar problem. Cyclones were many, but observations of individual cyclones, especially over the ocean, were sparse. The structure and dynamics of cyclones was unraveled by noting similarities in properties between certain classes of cyclones and using observational data to generate composite cyclones that could be analyzed and modeled. Variability within the composite also could be studied. Here I establish the existence of a well-defined class of Martian local dust storms defined by: (1) occurrence along the axis of the dark albedo feature in northern Amazonis Planitia (36 N, 155 W); (2) not being associated with lifting or cloudiness due to a baroclinic wave/frontal boundary at higher latitude; (3) being textured, that is, having dust clouds with sharp, well-defined features that are thought to indicate their clouds are supplied by the active lifting of dust; (4) having dust clouds organized in well-defined streets indicative of convective rolls. In Mars Year 24, such storms developed on thirteen occasions in northern fall and autumn. Using data from the Mars

  15. A comparison of the measured North Sea Andrea rogue wave with numerical simulations

    NASA Astrophysics Data System (ADS)

    Bitner-Gregersen, E. M.; Fernandez, L.; Lefèvre, J. M.; Monbaliu, J.; Toffoli, A.

    2013-09-01

    A coupling of a spectral wave model with a nonlinear phase resolving model is used to reconstruct the evolution of wave statistics during a storm crossing the North Sea on 8-9 November 2007. During this storm a rogue wave (named the Andrea wave) was recorded at the Ekofisk field. The wave has characteristics comparable to the well-known New Year wave measured by Statoil at the Draupner platform the 1 January 1995. Hindcast data of the storm are here applied as input to calculate random realizations of sea surface and evolution of its statistical properties associated with this specific wave event by solving the Euler equations with a Higher Order Spectral Method (HOSM). The numerical results are compared with the Andrea wave profile as well as characteristics of the Andrea wave record measured by the down-looking lasers at the Ekofisk field.

  16. Criteria of interplanetary parameters causing intense magnetic storms (Dst less than -100nT)

    NASA Technical Reports Server (NTRS)

    Gonzalez, Walter D.; Tsurutani, Bruce T.

    1987-01-01

    Ten intense storms occurred during the 500 days of August 16, 1978 to December 28, 1979. From the analysis of ISEE-3 field and plasma data, it is found that the interplanetary cause of these storms are long-duration, large and negative IMF B sub Z events, associated with interplanetary duskward-electric fields greater than 5 mV/m. Because a one-to-one relationship was found between these interplanetary events and intense storms, it is suggested that these criteria can, in the future, be used as predictors of intense storms by an interplanetary monitor such as ISEE-3. These B sub Z events are found to occur in association with large amplitudes of the IMF magnitude within two days after the onset of either high-speed solar wind streams or of solar wind density enhancement events, giving important clues to their interplanetary origin. Some obvious possibilities will be discussed. The close proximity of B sub Z events and magnetic storms to the onset of high speed streams or density enhancement events is in sharp contrast to interplanetary Alfven waves and HILDCAA events previously reported, and thus the two interplanetary features corresponding geomagnetic responses can be thought of as being complementary in nature. An examination of opposite polarity B sub Z events with the same criteria show that their occurrence is similar both in number as well as in their relationship to interplanetary disturbances, and that they lead to low levels of geomagnetic activity.

  17. 46 CFR 72.40-10 - Storm rails.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 3 2012-10-01 2012-10-01 false Storm rails. 72.40-10 Section 72.40-10 Shipping COAST... and Guards § 72.40-10 Storm rails. (a) Suitable storm rails shall be installed in all passageways and at the deckhouse sides where passengers or crew might have normal access. Storm rails shall...

  18. 46 CFR 72.40-10 - Storm rails.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 3 2013-10-01 2013-10-01 false Storm rails. 72.40-10 Section 72.40-10 Shipping COAST... and Guards § 72.40-10 Storm rails. (a) Suitable storm rails shall be installed in all passageways and at the deckhouse sides where passengers or crew might have normal access. Storm rails shall...

  19. 46 CFR 72.40-10 - Storm rails.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 3 2010-10-01 2010-10-01 false Storm rails. 72.40-10 Section 72.40-10 Shipping COAST... and Guards § 72.40-10 Storm rails. (a) Suitable storm rails shall be installed in all passageways and at the deckhouse sides where passengers or crew might have normal access. Storm rails shall...

  20. 46 CFR 72.40-10 - Storm rails.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 3 2014-10-01 2014-10-01 false Storm rails. 72.40-10 Section 72.40-10 Shipping COAST... and Guards § 72.40-10 Storm rails. (a) Suitable storm rails shall be installed in all passageways and at the deckhouse sides where passengers or crew might have normal access. Storm rails shall...

  1. 46 CFR 72.40-10 - Storm rails.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 3 2011-10-01 2011-10-01 false Storm rails. 72.40-10 Section 72.40-10 Shipping COAST... and Guards § 72.40-10 Storm rails. (a) Suitable storm rails shall be installed in all passageways and at the deckhouse sides where passengers or crew might have normal access. Storm rails shall...

  2. Radiation Belt Storm Probe Mission Trailer

    NASA Video Gallery

    With launch scheduled for 2012, the Radiation Belt Storm Probe (RBSP) are two identical spacecraft that will investigate the doughnut shaped Van Allen radiation belts, the first discovery of the sp...

  3. Tropical Storm Gilma in Eastern Pacific

    NASA Video Gallery

    An animation of satellite observations shows the progression of Tropical Storm Gilma from August 7-10, 2012, along the coast of the Eastern Pacific Ocean. This visualization was created by the NASA...

  4. GOES Satellite Movie of 2014 Winter Storms

    NASA Video Gallery

    This new animation of NOAA's GOES-East satellite imagery shows the movement of winter storms from January 1 to March 24 making for a snowier-than-normal winter along the U.S. East coast and Midwest...

  5. Satellite Movie Sees Southern California Storms

    NASA Video Gallery

    This animation NOAA's GOES-West satellite imagery from Jan. 5 through Jan 7 shows the progression of storm systems in the Eastern Pacific Ocean that hit southern California and generated flooding a...

  6. GMI Rainfall Data on Tropical Storm Adjali

    NASA Video Gallery

    This animation shows GMI rainfall data on Tropical Storm Adjali on Nov. 19, 2014 combined with cloud data from the METEOSAT-7 satellite. Rainfall was found to be falling at a rate of over 69 mm/hr ...

  7. Isaac's Remnants; Tropical Storms Kirk, Michael

    NASA Video Gallery

    Animation of GOES-13 satellite observations from Sept. 1-4, 2012, showing Isaac's remnants move from the central to eastern U.S., Tropical Storm Leslie nearing Bermuda, Kirk fading in the No. Atlan...

  8. Tropical Storm Wali Seen by GOESWest

    NASA Video Gallery

    This animation of infrared and visible imagery from NOAA's GOES-West satellite from July 15 to 18 shows the birth of Tropical Storm Wali southeast of the Big Island of Hawaii on July 17. Credit: NA...

  9. Satellite Sees Birth of Tropical Storm Gordon

    NASA Video Gallery

    An animation of satellite observations from August 13-16, 2012, shows the birth of the Atlantic Ocean hurricane season's eighth tropical depression that strengthens into Tropical Storm Gordon. This...

  10. TRMM Sees California Storm Move East

    NASA Video Gallery

    This animation from Feb. 28 to Mar. 3 shows the movement of the rain associated with the storm system that soaked California. On March 3, precipitation (yellow) and snow cover (white/yellow) spread...

  11. The Surprising Power of Solar Storms

    NASA Video Gallery

    NASA-funded researchers say a flurry of solar storms from March 8-10, 2012 dumped enough energy in Earth's upper atmosphere (our thermosphere absorbed 26 billion kWh of energy) to power every resid...

  12. GOES video of Tropical Storm Andrea

    NASA Video Gallery

    This NOAA GOES-East satellite animation shows the development of System 91L into Tropical Storm Andrea over the course of 3 days from June 4 to June 6, just after Andrea was officially designated a...

  13. Rainfall Totals Over Storm Life of Matthew

    NASA Video Gallery

    This animation shows the amount of rainfall dropped by Hurricane Matthew over the life and track of the storm/ IMERG real time data covering the period from Sept. 28 through Oct. 10, 2016 show rain...

  14. Tropical Storm Gil - July 31, 2013

    NASA Video Gallery

    NASA's TRMM satellite traveled above intensifying Tropical Storm Gil on July 31 at 12:55 a.m. EDT. The TRMM satellite pass showed that Gil was already very well organized with intense bands of rain...

  15. GOES Movie of Tropical Storm Danielle

    NASA Video Gallery

    This animation NOAA's GOES-East satellite imagery from June 18 to 20 shows the development and movement Tropical Storm Danielle from the western Caribbean Sea into the Bay of Campeche/Gulf of Mexic...

  16. Pacific Northwest Storms Situation Report # 1

    SciTech Connect

    2006-12-15

    Severe wind and snow storms hit the Pacific Northwest region on December 14 – 15, 2006, following severe flooding during the past few days. The severe weather resulted in major power outages through the region. At peak there were 1.8 million customers without power which included BC Hydro in Canada. Currently, there are over 1.5 million outages in the region as a result of the Pacific Northwest Storms. This represents about 42 percent of customers in affected utility service areas in Oregon and Washington. See table below. Because the current wind and snow storms are coming on the heels of extensive flooding in the region, electric utilities are experiencing damage. Wind gusts reached close to 100 mph in some areas of the region. The storm is expected to bring its strong winds and heavy snow into Idaho, Montana and Wyoming Friday and into the weekend. There are currently no reported major impacts to the petroleum and natural gas infrastructure.

  17. Nuclear magnetohydrodynamic EMP, solar storms, and substorms

    SciTech Connect

    Rabinowitz, M. ); Meliopoulous, A.P.S.; Glytsis, E.N. . School of Electrical Engineering); Cokkinides, G.J. )

    1992-10-20

    In addition to a fast electromagnetic pulse (EMP), a high altitude nuclear burst produces a relatively slow magnetohydrodynamic EMP (MHD EMP), whose effects are like those from solar storm geomagnetically induced currents (SS-GIC). The MHD EMP electric field E [approx lt] 10[sup [minus] 1] V/m and lasts [approx lt] 10[sup 2] sec, whereas for solar storms E [approx gt] 10[sup [minus] 2] V/m and lasts [approx gt] 10[sup 3] sec. Although the solar storm electric field is lower than MHD EMP, the solar storm effects are generally greater due to their much longer duration. Substorms produce much smaller effects than SS-GIC, but occur much more frequently. This paper describes the physics of such geomagnetic disturbances and analyzes their effects.

  18. UCAR group urges STORM program

    NASA Astrophysics Data System (ADS)

    Richman, Barbara T.

    A blue-ribbon panel of scientists has proposed a decade-long, $1 billion program to improve forecasting operations and research of regional and local hazardous weather. The panel, appointed by the University Corporation for Atmospheric Research (UCAR), believes that the program could reduce the $20-billion annual cost of damage from severe weather by $1 billion per year.The primary aim of the program is to ‘enable weather services, public and private, to observe and predict stormscale weather phenomena— such as squall lines, thunderstorms, flash floods, local heavy snows, or tornadoes—with the accuracy and reliability to protect the public, serve the national economy, and meet defense requirements,’ as explained in the report, The National STORM (Stormscale Operational and Research Meteorology) Program: A Call to Action. Stormscale phenomena also include nonviolent weather: freezing rain, dense ground fog, low-lying clouds that disrupt ground or air traffic, persistent temperature inversions, and strong nocturnal cooling that may produce killing frost.

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

    NASA Astrophysics Data System (ADS)

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

    2014-07-01

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

  20. Electron Acceleration and Radio Noise Storms

    NASA Astrophysics Data System (ADS)

    Vilmer, N.; Trottet, G.

    2008-05-01

    Radio noise storms are radiated by suprathermal electrons accelerated continuously over time scales of hours to days in the vicinity of active regions. Such long-duration electron acceleration may be related to emerging magnetic loops interacting with overlying loops leading to magnetic reconfiguration in the corona. A close spatial and temporal relationship is also sometimes observed between noise storm onsets or enhancements and white light transient activity. For a few cases, noise storm enhancements were found to be associated with flare like sudden energy release in the active region, either as a fully developed flare or, more often as a microwave or soft X-ray brightening without Halpha signature. A few cases have also been reported in which 10-30 keV X-rays from a superhot flaring plasma or from non-thermal electrons have been observed at the onset of the noise storm confirming that a flare-like signature in the low corona could be a necessary condition for noise storms to start. Most of these results were however obtained with no spatial resolution at X-ray wavelengths allowing us to confirm that the flare-like signature was indeed related to the radio noise storm onset. We shall present here some results of a search of X-ray counterparts (observed by RHESSI) at the onset or enhancements of a few radio noise storms observed with the Nançay Radioheliograph. We shall investigate whether X-ray flare-like signatures are seen in close temporal and spatial association with the appearance of the noise storm and briefly discuss the thermal or non thermal nature of the emission as well as its energy content.

  1. EVIDENCE FOR COMET STORMS IN METEORITE AGES

    SciTech Connect

    Perlmutter, S.; Muller, R.A.

    1987-10-01

    Clustering of cosmic-ray exposure ages of H chondritic meteorites occurs at 7 {+-} 3 and 30 {+-} 6 Myr ago. There is independent evidence that comet storms have occurred at the same times, based on the fossil record of family and genus extinctions, impact craters and glass, and geomagnetic reversals. We suggest that H chondrites were formed by the impact of shower comets on asteroids. The duration of the most recent comet shower was {le} 4 Myr, in agreement with storm theory.

  2. Ionospheric storm effects at subauroral latitudes - A case study

    NASA Technical Reports Server (NTRS)

    Proelss, G. W.; Brace, L. H.; Mayr, H. G.; Carignan, G. R.; Killeen, T. L.

    1991-01-01

    An attempt is made to classify ionospheric storm effects at subauroral latitudes according to their presumed origin. The storm of December 7/8, 1982, serves as an example. It is investigated using ionosonde, electron content, and DE 2 satellite data. The following effects are distinguished: (1) positive storm effects caused by traveling atmospheric disturbances, (2) positive storm effects caused by changes in the large-scale thermospheric wind circulation, (3) positive storm effects caused by the expansion of the polar ionization enhancement, (4) negative storm effects caused by perturbations of the neutral gas composition, and (5) negative storm effects caused by the equatorward displacement of the trough region.

  3. Measuring Bathymetry, Runup, and Beach Volume Change during Storms: New Methodology Quantifies Substantial Changes in Cross-Shore Sediment Flux

    NASA Astrophysics Data System (ADS)

    Brodie, K. L.; McNinch, J. E.

    2009-12-01

    Accurate predictions of beach change during storms are contingent upon a correct understanding of wave-driven sediment exchange between the beach and nearshore during high energy conditions. Conventional storm data sets use “pre” (often weeks to months prior) and “post” (often many days after the storm in calm conditions) collections of beach topography and nearshore bathymetry to characterize the effects of the storm. These data have led to a common theory for wave-driven event response of the nearshore system, wherein bars and shorelines are smoothed and straightened by strong alongshore currents into two-dimensional, linear forms. Post-storm, the shoreline accretes, bars migrate onshore, and three-dimensional shapes begin to build as low-energy swell returns. Unfortunately, these approaches have left us with a knowledge gap of the extent and timing of erosion and accretion during storms, arguably the most important information both for scientists trying to model storm damage or inundation, and homeowners trying to manage their properties. This work presents the first spatially extensive (10 km alongshore) and temporally high-resolution (dt = 12 hours) quantitative data set of beach volume and nearshore bathymetry evolution during a Nor’easter on North Carolina’s Outer Banks. During the Nor’easter, significant wave height peaked at 3.4 m, and was greater than 2 m for 37 hours, as measured by the Duck FRF 8 m array. Data were collected using CLARIS: Coastal Lidar and Radar Imaging System, a mobile system that couples simultaneous observations of beach topography from a Riegl laser scanner and nearshore bathymetry (out to ~1 km offshore) from X-Band radar-derived celerity measurements (BASIR). The merging of foreshore lidar elevations with 6-min averages of radar-derived swash runup also enables mapping of maximum-runup elevations alongshore during the surveys. Results show that during the storm, neither the shoreline nor nearshore bathymetry returned

  4. Field Evaluation of Low-E Storm Windows

    SciTech Connect

    Drumheller, S. Craig; Kohler, Christian; Minen, Stefanie

    2007-07-11

    A field evaluation comparing the performance of low emittance (low-e) storm windows with both standard clear storm windows and no storm windows was performed in a cold climate. Six homes with single-pane windows were monitored over the period of one heating season. The homes were monitored with no storm windows and with new storm windows. The storm windows installed on four of the six homes included a hard coat, pyrolitic, low-e coating while the storm windows for the other two homeshad traditional clear glass. Overall heating load reduction due to the storm windows was 13percent with the clear glass and 21percent with the low-e windows. Simple paybacks for the addition of the storm windows were 10 years for the clear glass and 4.5 years forthe low-e storm windows.

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

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

  6. Non-storm water discharges technical report

    SciTech Connect

    Mathews, S.

    1994-07-01

    Lawrence Livermore National Laboratory (LLNL) submitted a Notice of Intent to the California State Water Resources Control Board (hereafter State Board) to discharge storm water associated with industrial activities under the California General Industrial Activity Storm Water National Pollutant Elimination System Discharge Permit (hereafter General Permit). As required by the General Permit, LLNL provided initial notification of non-storm water discharges to the Central Valley Regional Water Quality Control Board (hereafter Regional Board) on October 2, 1992. Additional findings and progress towards corrective actions were reported in subsequent annual monitoring reports. LLNL was granted until March 27, 1995, three years from the Notice of Intent submission date, to eliminate or permit the non-storm water discharges. On May 20, 1994, the Regional Board issued Waste Discharge Requirements (WDR Board Order No. 94-131, NPDES No. CA0081396) to LLNL for discharges of non-contact cooling tower wastewater and storm water related to industrial activities. As a result of the issuance of WDR 94-131, LLNL rescinded its coverage under the General Permit. WDR 94-131 allowed continued non-storm water discharges and requested a technical report describing the discharges LLNL seeks to permit. For the described discharges, LLNL anticipates the Regional Board will either waive Waste Discharge Requirements as allowed for in The Water Quality Control Plan for the California Regional Water Quality Control Board, Central Valley Region (hereafter Basin Plan) or amend Board Order 94-131 as appropriate.

  7. Total Lightning Activity Associated with Tornadic Storms

    NASA Technical Reports Server (NTRS)

    Goodman, Steven J.; Buechler, Dennis; Hodanish, Stephen; Sharp, David; Williams, Earle; Boldi, Bob; Matlin, Anne; Weber, Mark

    1999-01-01

    Severe storms often have high flash rates (in excess of one flash per second) and are dominated by intracloud lightning activity. In addition to the extraordinary flash rates, there is a second distinguishing lightning characteristic of severe storms that seems to be important. When the total lightning history is examined, one finds sudden increases in the lightning rate, which we refer to as lightning "jumps," that precede the occurrence of severe weather by ten or more minutes. These jumps are typically 30-60 flashes/min, and are easily identified as anomalously large derivatives in the flash rate. This relationship is associated with updraft intensification and updraft strength is an important factor in storm severity (through the accumulation of condensate aloft and the stretching of vorticity). In several cases, evidence for diminishment of midlevel rotation and the descent of angular momentum from aloft is present prior to the appearance of the surface tornado. Based on our experience with severe and tornadic storms in Central Florida, we believe the total lightning may augment the more traditional use of NEXRAD radars and storm spotters. However, a more rigorous relation of these jumps to storm kinematics is needed if we are to apply total lightning in a decision tree that leads to improved warning lead times and decreased false alarm rates.

  8. Mapping Hurricane Rita inland storm tide

    USGS Publications Warehouse

    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.

  9. Mapping hurricane rita inland storm tide

    USGS Publications Warehouse

    Berenbrock, C.; Mason, R.R.; Blanchard, S.F.

    2009-01-01

    Flood-inundation data are most useful for decision makers when presented in the context of maps of affected 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 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-h intervals from midnight (00:00 hours) through noon (12:00 hours) on 24 September 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 with 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. ?? 2009 Blackwell Publishing Ltd.

  10. Scientists Track 'Perfect Storm' on Mars

    NASA Technical Reports Server (NTRS)

    2001-01-01

    Two dramatically different faces of our Red Planet neighbor appear in these comparison images showing how a global dust storm engulfed Mars with the onset of Martian spring in the Southern Hemisphere. When NASA's Hubble Space Telescope imaged Mars in June, the seeds of the storm were caught brewing in the giant Hellas Basin (oval at 4 o'clock position on disk) and in another storm at the northern polar cap.

    When Hubble photographed Mars in early September, the storm had already been raging across the planet for nearly two months obscuring all surface features. The fine airborne dust blocks a significant amount of sunlight from reaching the Martian surface. Because the airborne dust is absorbing this sunlight, it heats the upper atmosphere. Seasonal global Mars dust storms have been observed from telescopes for over a century, but this is the biggest storm ever seen in the past several decades.

    Mars looks gibbous in the right photograph because it is 26 million miles farther from Earth than in the left photo (though the pictures have been scaled to the same angular size), and our viewing angle has changed. The left picture was taken when Mars was near its closest approach to Earth for 2001 (an event called opposition); at that point the disk of Mars was fully illuminated as seen from Earth because Mars was exactly opposite the Sun.

    Both images are in natural color, taken with Hubble's Wide Field Planetary Camera 2.

  11. Development of the Coastal Storm Modeling System (CoSMoS) for predicting the impact of storms on high-energy, active-margin coasts

    USGS Publications Warehouse

    Barnard, Patrick; Maarten van Ormondt,; Erikson, Li H.; Jodi Eshleman,; Hapke, Cheryl J.; Peter Ruggiero,; Peter Adams,; Foxgrover, Amy

    2014-01-01

    The Coastal Storm Modeling System (CoSMoS) applies a predominantly deterministic framework to make detailed predictions (meter scale) of storm-induced coastal flooding, erosion, and cliff failures over large geographic scales (100s of kilometers). CoSMoS was developed for hindcast studies, operational applications (i.e., nowcasts and multiday forecasts), and future climate scenarios (i.e., sea-level rise + storms) to provide emergency responders and coastal planners with critical storm hazards information that may be used to increase public safety, mitigate physical damages, and more effectively manage and allocate resources within complex coastal settings. The prototype system, developed for the California coast, uses the global WAVEWATCH III wave model, the TOPEX/Poseidon satellite altimetry-based global tide model, and atmospheric-forcing data from either the US National Weather Service (operational mode) or Global Climate Models (future climate mode), to determine regional wave and water-level boundary conditions. These physical processes are dynamically downscaled using a series of nested Delft3D-WAVE (SWAN) and Delft3D-FLOW (FLOW) models and linked at the coast to tightly spaced XBeach (eXtreme Beach) cross-shore profile models and a Bayesian probabilistic cliff failure model. Hindcast testing demonstrates that, despite uncertainties in preexisting beach morphology over the ~500 km alongshore extent of the pilot study area, CoSMoS effectively identifies discrete sections of the coast (100s of meters) that are vulnerable to coastal hazards under a range of current and future oceanographic forcing conditions, and is therefore an effective tool for operational and future climate scenario planning.

  12. Chromosomal abnormalities in human sperm

    SciTech Connect

    Martin, R.H.

    1985-01-01

    The ability to analyze human sperm chromosome complements after penetration of zona pellucida-free hamster eggs provides the first opportunity to study the frequency and type of chromosomal abnormalities in human gametes. Two large-scale studies have provided information on normal men. We have studied 1,426 sperm complements from 45 normal men and found an abnormality rate of 8.9%. Brandriff et al. (5) found 8.1% abnormal complements in 909 sperm from 4 men. The distribution of numerical and structural abnormalities was markedly dissimilar in the 2 studies. The frequency of aneuploidy was 5% in our sample and only 1.6% in Brandriff's, perhaps reflecting individual variability among donors. The frequency of 24,YY sperm was low: 0/1,426 and 1/909. This suggests that the estimates of nondisjunction based on fluorescent Y body data (1% to 5%) are not accurate. We have also studied men at increased risk of sperm chromosomal abnormalities. The frequency of chromosomally unbalanced sperm in 6 men heterozygous for structural abnormalities varied dramatically: 77% for t11;22, 32% for t6;14, 19% for t5;18, 13% for t14;21, and 0% for inv 3 and 7. We have also studied 13 cancer patients before and after radiotherapy and demonstrated a significant dose-dependent increase of sperm chromosome abnormalities (numerical and structural) 36 months after radiation treatment.

  13. The influence of topography on vertical velocity of air in relation to severe storms near the Southern Andes Mountains

    NASA Astrophysics Data System (ADS)

    de la Torre, A.; Pessano, H.; Hierro, R.; Santos, J. R.; Llamedo, P.; Alexander, P.

    2015-04-01

    On the basis of 180 storms which took place between 2004 and 2011 over the province of Mendoza (Argentina) near to the Andes Range at southern mid-latitudes, we consider those registered in the northern and central crop areas (oases). The regions affected by these storms are currently protected by an operational hail mitigation project. Differences with previously reported storms detected in the southern oasis are highlighted. Mendoza is a semiarid region situated roughly between 32S and 37S at the east of the highest Andes top. It forms a natural laboratory where different sources of gravity waves, mainly mountain waves, occur. In this work, we analyze the effects of flow over topography generating mountain waves and favoring deep convection. The joint occurrence of storms with hail production and mountain waves is determined from mesoscale numerical simulations, radar and radiosounding data. In particular, two case studies that properly represent diverse structures observed in the region are considered in detail. A continuous wavelet transform is applied to each variable and profile to detect the main oscillation modes present. Simulated temperature profiles are validated and compared with radiosounding data. Each first radar echo, time and location are determined. The necessary energy to lift a parcel to its level of free convection is tested from the Convective Available Potential Energy and Convection Inhibition. This last parameter is compared against the mountain waves' vertical kinetic energy. The time evolution and vertical structure of vertical velocity and equivalent potential temperature suggest in both cases that the detected mountain wave amplitudes are able to provide the necessary energy to lift the air parcel and trigger convection. A simple conceptual scheme linking the dynamical factors taking place before and during storm development is proposed.

  14. Paleo-tsunami and storm records inferred from coastal boulders along the Ryukyu Islands, Japan

    NASA Astrophysics Data System (ADS)

    Goto, K.; Miyagi, K.; Imamura, F.

    2012-12-01

    After the 11 March 2011 Tohoku-oki earthquake and tsunami (Mw=9.0) at off the coast of Tohoku district of Japan, re-evaluation of the occurrence of large earthquake and tsunami along the subduction zone is one of the major issues in Japan. Along the Ryukyu trench, there are no known thrust type earthquakes of magnitude greater than 8.0 in the last 300 years [Ando et al., 2009, 2012], although there is one possible exception: the AD1771 event at the southern Ryukyu Islands which is characterized by the ~30 m run-up heights. Hence, the occurrence of tsunamigenic large earthquake along the Ryukyu trench in the past and future is controversial. The lack of thousands of years geological record of past earthquake and tsunami such as the sandy tsunami deposits along the Ryukyu trench has made the discussion more difficult, because there are very few suitable places to study such deposits. On the other hand, numerous coastal boulders are reported on the fringing reefs of each island [e.g. Goto et al., 2010]. They are mostly composed of the coralline and reef rocks and are regarded as useful markers of the past large tsunamis and storm events. In fact, some of them are fossil Porites sp. and hence 14C dating is possible for determining the depositional age [e.g. Araoka et al., 2010]. Moreover, boulders of tsunami and storm wave origins at Ryukyu Islands can be differentiated because difference of the wave lengths of tsunami and storm wave are affected the clast size and spatial distributions of boulders on the wide fringing reef (~1500 m) [e.g. Goto et al., 2010]. Therefore, presence or absence of tsunami boulders at each island may provide useful information of occurrence of past large tsunamis and the causative earthquakes along the Ryukyu Trench. In this study, we show the clast size and spatial distributions of more than 2,500 boulders at 11 islands along the Ryukyu trench. Based on the geological study and hydrodynamic analyses, boulders on the reefs at the Sakishima

  15. Ionospheric acoustic and gravity waves associated with midlatitude thunderstorms

    SciTech Connect

    Lay, Erin H.; Shao, Xuan -Min; Kendrick, Alexander K.; Carrano, Charles S.

    2015-07-30

    Acoustic waves with periods of 2–4 min and gravity waves with periods of 6–16 min have been detected at ionospheric heights (25–350 km) using GPS total electron content measurements. The area disturbed by these waves and the wave amplitudes have been associated with underlying thunderstorm activity. A statistical study comparing Next Generation Weather Radar thunderstorm measurements with ionospheric acoustic and gravity waves in the midlatitude U.S. Great Plains region was performed for the time period of May–July 2005. An increase of ionospheric acoustic wave disturbed area and amplitude is primarily associated with large thunderstorms (mesoscale convective systems). Ionospheric gravity wave disturbed area and amplitude scale with thunderstorm activity, with even small storms (i.e., individual storm cells) producing an increase of gravity waves.

  16. Association of Traditional Cardiovascular Risk Factors With Development of Major and Minor Electrocardiographic Abnormalities: A Systematic Review.

    PubMed

    Healy, Caroline F; Lloyd-Jones, Donald M

    2016-01-01

    Electrocardiographic (ECG) abnormalities are prevalent in middle aged and are associated with risk of adverse cardiovascular events. It is unclear whether and to what extent traditional risk factors are associated with the development of ECG abnormalities. To determine whether traditional cardiovascular risk factors are associated with the presence or development of ECG abnormalities, we performed a systematic review of the English-language literature for cross-sectional and prospective studies examining associations between traditional cardiovascular risk factors and ECG abnormalities, including major and minor ECG abnormalities, isolated nonspecific ST-segment and T-wave abnormalities, other ST-segment and T-wave abnormalities, QT interval, Q waves, and QRS duration. Of the 202 papers initially identified, 19 were eligible for inclusion. We examined data analyzing risk factor associations with ECG abnormalities in individuals free of cardiovascular disease. For composite major or minor ECG abnormalities, black race, older age, higher blood pressure, use of antihypertensive medications, higher body mass index, diabetes, smoking, and evidence of left ventricular hypertrophy or higher left ventricular mass are the factors most commonly associated with prevalence and incidence. Risk factor associations differ somewhat according to types of specific ECG abnormalities. Because major and minor ECG abnormalities have important and independent prognostic significance, understanding the groups at risk for their development may inform prevention strategies focused on modifiable risk factors to reduce the burden of ECG abnormalities, which may in turn promote CVD prevention. PMID:27054606

  17. Ionospheric data assimilation and forecasting during storms

    NASA Astrophysics Data System (ADS)

    Chartier, Alex T.; Matsuo, Tomoko; Anderson, Jeffrey L.; Collins, Nancy; Hoar, Timothy J.; Lu, Gang; Mitchell, Cathryn N.; Coster, Anthea J.; Paxton, Larry J.; Bust, Gary S.

    2016-01-01

    Ionospheric storms can have important effects on radio communications and navigation systems. Storm time ionospheric predictions have the potential to form part of effective mitigation strategies to these problems. Ionospheric storms are caused by strong forcing from the solar wind. Electron density enhancements are driven by penetration electric fields, as well as by thermosphere-ionosphere behavior including Traveling Atmospheric Disturbances and Traveling Ionospheric Disturbances and changes to the neutral composition. This study assesses the effect on 1 h predictions of specifying initial ionospheric and thermospheric conditions using total electron content (TEC) observations under a fixed set of solar and high-latitude drivers. Prediction performance is assessed against TEC observations, incoherent scatter radar, and in situ electron density observations. Corotated TEC data provide a benchmark of forecast accuracy. The primary case study is the storm of 10 September 2005, while the anomalous storm of 21 January 2005 provides a secondary comparison. The study uses an ensemble Kalman filter constructed with the Data Assimilation Research Testbed and the Thermosphere Ionosphere Electrodynamics General Circulation Model. Maps of preprocessed, verticalized GPS TEC are assimilated, while high-latitude specifications from the Assimilative Mapping of Ionospheric Electrodynamics and solar flux observations from the Solar Extreme Ultraviolet Experiment are used to drive the model. The filter adjusts ionospheric and thermospheric parameters, making use of time-evolving covariance estimates. The approach is effective in correcting model biases but does not capture all the behavior of the storms. In particular, a ridge-like enhancement over the continental USA is not predicted, indicating the importance of predicting storm time electric field behavior to the problem of ionospheric forecasting.

  18. Ionospheric Storms in Equatorial Region: Digisonde Observations

    NASA Astrophysics Data System (ADS)

    Paznukhov, V.; Altadill, D.; Blanch, E.

    2011-12-01

    We present a study of the ionospheric storms observed in the low-latitude and equatorial ionosphere at several digisonde stations: Jicamarca (Geomagnetic Coordinates: 2.0 S, 355.3 E), Kwajalein Island (3.8 N, 238.2 E), Ascension Island (2.5 S, 56.8 E), Fortaleza (4.8 N, 33.7 W), and Ramey (28.6 N, 5.2 E). The strongest geomagnetic storms from years 1995-2009 have been analyzed. The main ionospheric characteristics, hmF2 and foF2 were used in the study, making it possible to investigate the changes in the ionosphere peak density and height during the storms. All digisonde data were manually processed to assure the accuracy of the measurements. Solar wind data, geomagnetic field variations, and auroral activity indices have been used to characterize the geomagnetic environment during the events. It was found in our analysis that the major drivers for the ionospheric storms, electric field and neutral wind have approximately equal importance at the low-latitude and equatorial latitudes. This is noticeably different from the behavior of the ionsphere in the middle latitudes, where the neutral wind is usually a dominant factor. It was found that the auroral index, AE is the best precursor of the ionospheric effects observed during the storms in this region. We analyze the difference between time delays of the storm effects observed at the stations located in different local time sectors. The overall statistics of the time delays of the storms as a function of the local time at the stations is also presented. Several very interesting cases of sudden very strong ionospheric uplifting and their possible relation to the equatorial super fountain effect are investigated in greater details.

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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