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Sample records for gulf stream ends

  1. Gulf stream separation dynamics

    NASA Astrophysics Data System (ADS)

    Schoonover, Joseph

    Climate models currently struggle with the more traditional, coarse ( O(100 km) ) representation of the ocean. In these coarse ocean simulations, western boundary currents are notoriously difficult to model accurately. The modeled Gulf Stream is typically seen exhibiting a mean pathway that is north of observations, and is linked to a warm sea-surface temperature bias in the Mid-Atlantic Bight. Although increased resolution ( O(10 km) ) improves the modeled Gulf Stream position, there is no clean recipe for obtaining the proper pathway. The 70 year history of literature on the Gulf Stream separation suggests that we have not reached a resolution on the dynamics that control the current's pathway just south of the Mid-Atlantic Bight. Without a concrete knowledge on the separation dynamics, we cannot provide a clean recipe for accurately modeling the Gulf Stream at increased resolutions. Further, any reliable parameterization that yields a realistic Gulf Stream path must express the proper physics of separation. The goal of this dissertation is to determine what controls the Gulf Stream separation. To do so, we examine the results of a model intercomparison study and a set of numerical regional terraforming experiments. It is argued that the separation is governed by local dynamics that are most sensitive to the steepening of the continental shelf, consistent with the topographic wave arrest hypothesis of Stern (1998). A linear extension of Stern's theory is provided, which illustrates that wave arrest is possible for a continuously stratified fluid.

  2. Temperature of the Gulf Stream

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The Gulf Stream is one of the strong ocean currents that carries warm water from the sunny tropics to higher latitudes. The current stretches from the Gulf of Mexico up the East Coast of the United States, departs from North America south of the Chesapeake Bay, and heads across the Atlantic to the British Isles. The water within the Gulf Stream moves at the stately pace of 4 miles per hour. Even though the current cools as the water travels thousands of miles, it remains strong enough to moderate the Northern European climate. The image above was derived from the infrared measurements of the Moderate-resolution Imaging Spectroradiometer (MODIS) on a nearly cloud-free day over the east coast of the United States. The coldest waters are shown as purple, with blue, green, yellow, and red representing progressively warmer water. Temperatures range from about 7 to 22 degrees Celsius. The core of the Gulf Stream is very apparent as the warmest water, dark red. It departs from the coast at Cape Hatteras, North Carolina. The cool, shelf water from the north entrains the warmer outflows from the Chesapeake and Delaware Bays. The north wall of the Gulf Stream reveals very complex structure associated with frontal instabilities that lead to exchanges between the Gulf Stream and inshore waters. Several clockwise-rotating warm core eddies are evident north of the core of the Gulf Stream, which enhance the exchange of heat and water between the coastal and deep ocean. Cold core eddies, which rotate counter clockwise, are seen south of the Gulf Stream. The one closest to Cape Hatteras is entraining very warm Gulf Stream waters on its northwest circumference. Near the coast, shallower waters have warmed due to solar heating, while the deeper waters offshore are markedly cooler (dark blue). MODIS made this observation on May 8, 2000, at 11:45 a.m. EDT. For more information, see the MODIS-Ocean web page. The sea surface temperature image was created at the University of Miami using

  3. Local sensitivities of the gulf stream separation

    DOE PAGES

    Schoonover, Joseph; Dewar, William K.; Wienders, Nicolas; ...

    2016-12-05

    Robust and accurate Gulf Stream separation remains an unsolved problem in general circulation modeling whose resolution will positively impact the ocean and climate modeling communities. Oceanographic literature does not face a shortage of plausible hypotheses that attempt to explain the dynamics of the Gulf Stream separation, yet a single theory that the community agrees on is missing. We investigate the impact of the Deep Western Boundary Current, coastline curvature, and continental shelf steepening on the Gulf Stream separation within regional configurations of the MIT General Circulation Model. Artificial modifications to the regional bathymetry are introduced to investigate the sensitivity ofmore » the separation to each of these factors. Metrics for subsurface separation detection confirm the direct link between flow separation and the surface expression of the Gulf Stream in the Mid-Atlantic Bight. Conversely, the Gulf Stream separation exhibits minimal sensitivity to the presence of the DWBC and coastline curvature. The implications of these results to the development of a “separation recipe” for ocean modeling are discussed. Furthermore, we conclude adequate topographic resolution is a necessary, but not sufficient, condition for proper Gulf Stream separation.« less

  4. Local sensitivities of the gulf stream separation

    SciTech Connect

    Schoonover, Joseph; Dewar, William K.; Wienders, Nicolas; Deremble, Bruno

    2016-12-05

    Robust and accurate Gulf Stream separation remains an unsolved problem in general circulation modeling whose resolution will positively impact the ocean and climate modeling communities. Oceanographic literature does not face a shortage of plausible hypotheses that attempt to explain the dynamics of the Gulf Stream separation, yet a single theory that the community agrees on is missing. We investigate the impact of the Deep Western Boundary Current, coastline curvature, and continental shelf steepening on the Gulf Stream separation within regional configurations of the MIT General Circulation Model. Artificial modifications to the regional bathymetry are introduced to investigate the sensitivity of the separation to each of these factors. Metrics for subsurface separation detection confirm the direct link between flow separation and the surface expression of the Gulf Stream in the Mid-Atlantic Bight. Conversely, the Gulf Stream separation exhibits minimal sensitivity to the presence of the DWBC and coastline curvature. The implications of these results to the development of a “separation recipe” for ocean modeling are discussed. Furthermore, we conclude adequate topographic resolution is a necessary, but not sufficient, condition for proper Gulf Stream separation.

  5. The Gulf Stream and Density of Fluids

    ERIC Educational Resources Information Center

    Landstrom, Erich

    2006-01-01

    A few kilometers from the shores of Palm Beach County, Florida, is the Gulf Stream current--a remarkable "river" within an ocean. The current's journey across the Atlantic Ocean connects southeast Florida and southwest Great Britain as it streams steadily north at speeds of 97 km a day; moving 100 times as much water as all the rivers on…

  6. Modeling the Gulf Stream System: How Far from Reality?

    NASA Technical Reports Server (NTRS)

    Choa, Yi; Gangopadhyay, Avijit; Bryan, Frank O.; Holland, William R.

    1996-01-01

    Analyses of a primitive equation ocean model simulation of the Atlantic Ocean circulation at 1/6 deg horizontal resolution are presented with a focus on the Gulf Stream region. Among many successful features of this simulation, this letter describes the Gulf Stream separation from the coast of North America near Cape Hatteras, meandering of the Gulf Stream between Cape Hatteras and the Grand Banks, and the vertical structure of temperature and velocity associated with the Gulf Stream. These results demonstrate significant improvement in modeling the Gulf Stream system using basin- to global scale ocean general circulation models. Possible reasons responsible for the realistic Gulf Stream simulation are discussed, contrasting the major differences between the present model configuration and those of previous eddy resolving studies.

  7. The influence of the Gulf Stream on wintertime European blocking

    NASA Astrophysics Data System (ADS)

    O'Reilly, Christopher H.; Minobe, Shoshiro; Kuwano-Yoshida, Akira

    2016-09-01

    Wintertime blocking is responsible for extended periods of anomalously cold and dry weather over Europe. In this study, the influence of the Gulf Stream sea surface temperature (SST) front on wintertime European blocking is investigated using a reanalysis dataset and a pair of atmospheric general circulation model (AGCM) simulations. The AGCM is forced with realistic and smoothed Gulf Stream SST, and blocking frequency over Europe is found to depend crucially on the Gulf Stream SST front. In the absence of the sharp SST gradient European blocking is significantly reduced and occurs further downstream. The Gulf Stream is found to significantly influence the surface temperature anomalies during blocking periods and the occurrence of associated cold spells. In particular the cold spell peak, located in central Europe, disappears in the absence of the Gulf Stream SST front. The nature of the Gulf Stream influence on European blocking development is then investigated using composite analysis. The presence of the Gulf Stream SST front is important in capturing the observed quasi-stationary development of European blocking. The development is characterised by increased lower-tropospheric meridional eddy heat transport in the Gulf Stream region and increased eddy kinetic energy at upper-levels, which acts to reinforce the quasi-stationary jet. When the Gulf Stream SST is smoothed the storm track activity is weaker, the development is less consistent and European blocking occurs less frequently.

  8. Gulf Stream eddies - Recent observations in the western Sargasso Sea.

    NASA Technical Reports Server (NTRS)

    Richardson, P. L.; Knauss, J. A.; Strong, A. E.

    1973-01-01

    A cyclonic Gulf Stream eddy was observed in the western Sargasso Sea by satellite infrared measurements and later confirmed by ship measurements. Fourteen months of observations indicate that the eddy moved southwestward at an average rate of 1 mile per day. The evidence suggests that the eddy was absorbed by the Gulf Stream off Florida.

  9. Gulf Stream - subtropical gyre properties across two Dansgaard-Oeschger cycles

    NASA Astrophysics Data System (ADS)

    Hoogakker, B. A. A.; Downy, F.; Andersson, M. A.; Chapman, M. R.; Elderfield, H.; McCave, I. N.; Lenton, T. M.; Grützner, J.

    2013-12-01

    Salinity increase in the subtropical gyre system may have pre-conditioned the North Atlantic Ocean for a rapid return to stronger overturning circulation and high-latitude warming following meltwater events during the Last Glacial period. Here we investigate the Gulf Stream - subtropical gyre system properties over Dansgaard-Oeschger (DO) cycles 14 to 12, including Heinrich ice-rafting event 5. During the Holocene and Last Glacial Maximum a positive gradient in surface dwelling planktonic foraminifera δ18O (Globigerinoides ruber) can be observed between the Gulf Stream and subtropical gyre, due to decreasing temperature, increasing salinity, and a change from summer to year-round occurrence of G. ruber. We assess whether this gradient was a common feature during stadial-interstadial climate oscillations of Marine Isotope Stage 3, by comparing existing G. ruber δ18O from ODP Site 1060 (subtropical gyre location) and new data from ODP Site 1056 (Gulf Stream location) between 54 and 46 ka. Our results suggest that this gradient was largely absent during the period studied. During the major warm DO interstadials 14 and 12 we infer a more zonal and wider Gulf Stream, influencing both ODP Sites 1056 and 1060. A Gulf Stream presence during these major interstadials is also suggested by the large vertical δ18O gradient between shallow dwelling planktonic foraminifera species, especially G. ruber, and the deep dwelling species Globorotalia inflata at site 1056, which we associate with strong summer stratification and Gulf Stream presence. A major reduction in this vertical δ18O gradient from 51 ka until the end of Heinrich event 5 at 48.5 ka suggests site 1056 was situated within the subtropical gyre in this mainly cold period, from which we infer a migration of the Gulf Stream to a position nearer to the continental shelf, indicative of a narrower Gulf Stream with possibly reduced transport.

  10. New marine evidence for a Late Wisconsinan ice stream in Amundsen Gulf, Arctic Canada

    NASA Astrophysics Data System (ADS)

    MacLean, B.; Blasco, S.; Bennett, R.; Lakeman, T.; Hughes-Clarke, J.; Kuus, P.; Patton, E.

    2015-04-01

    Amundsen Gulf and adjoining Dolphin and Union Strait and Coronation Gulf form the southwestern end of the Northwest Passage adjacent to the Beaufort Sea. Extensive high resolution multibeam sonar imagery and sub-bottom profiles of the seabed have been acquired, primarily in Amundsen Gulf, by ArcticNet and the Ocean Mapping Group at the University of New Brunswick. These data reveal a variety of seabed landforms including mega-scale glacial ridge and groove lineations, drumlins, moraines, iceberg scours, bedrock outcrops, and discontinuous sediment deposits of variable thickness. The lineations are widespread, especially in southeastern Amundsen Gulf. They resemble modern and paleo bedforms reported from Antarctica, Svalbard, Greenland and other Canadian Arctic channels, where they have been ascribed to ice streams. The glacial sole marks on the seabed in Amundsen Gulf and regional data from the adjacent mainland and islands outline the configuration of a glacial ice stream from the Laurentide Ice Sheet that occupied Amundsen Gulf and adjoining waterways during the Late Wisconsinan. Part of the northwestward flowing ice stream was deflected around the Colville Mountains on Victoria Island and rejoined the main ice stream in Amundsen Gulf by way of Prince Albert Sound. The grounded Amundsen Gulf ice stream extended northwestward to the outer slope in the Beaufort Sea where it was buttressed by Arctic Shelf Ice. Maximum ice stream extent is inferred to have been coincident with the Late Glacial Maximum. Multi-sequence ice-contact sediments and stratigraphic relations with glaciomarine sediments indicate that several ice advances and retreats occurred in the northwestern part of the gulf. Final retreat from the maximum position began prior to 13,000 cal yr BP and terrestrial dates indicate that the retreating ice front had reached Dolphin and Union Strait by about 12.5 cal ka BP.

  11. Salinity Measurements During the Gulf Stream Experiment

    NASA Technical Reports Server (NTRS)

    LeVine, D. M.; Koblinsky, C.; Howden, S.; Goodberlet, M.

    2000-01-01

    The salinity of the open ocean is important for understanding ocean circulation, for understanding energy exchange with the atmosphere and for improving models to predict weather and climate. Passive microwave sensors at L-band (1.4 GHz) operating from aircraft have demonstrated that salinity can be measured with sufficient accuracy (1 psu) to be scientifically meaningful in coastal waters. However, measuring salinity in the open ocean presents unresolved issues largely because of the much greater accuracy (approx. 0.1 psu) required to be scientifically viable. In the summer of 1999 a series of measurements called, The Gulf Stream Experiment, were conducted as part of research at the Goddard Space Flight Center to test the potential for passive microwave remote sensing of salinity in the open ocean. The measurements consisted of a compliment of airborne microwave instruments (radiometers and scatterometer) and ships and drifters for surface truth. The study area was a 200 km by 100 km rectangle about 250 km east of Delaware Bay between the continental shelf waters and north wall of the Gulf Stream. The primary passive instruments were the ESTAR radiometer (L-band, H-pol) and the SLFMR radiometer (L-band, V-pol). In addition, the compliment of instruments on the aircraft included a C-band radiometer (ACMR), an ocean wave scatterometer (ROWS) and an infrared radiometer. A GPS backscatter experiment was also part of the package. These instruments were mounted on the NASA P-3 Orion aircraft. Surface salinity measurements were provided by the RN Cape Henlopen and MN Oleander (thermosalinographs) plus salinity and temperature sensors on three surface drifters deployed from the RN Cape Henopen. The primary experiment period was August 26-September 2, 1999. During this period the salinity field within the study area consisted of a gradient on the order of 2-3 psu in the vicinity of the shelf break and a warm core ring with a gradient of 1-2 psu. Detailed maps were made

  12. Influence of the Gulf Stream on the troposphere.

    PubMed

    Minobe, Shoshiro; Kuwano-Yoshida, Akira; Komori, Nobumasa; Xie, Shang-Ping; Small, Richard Justin

    2008-03-13

    The Gulf Stream transports large amounts of heat from the tropics to middle and high latitudes, and thereby affects weather phenomena such as cyclogenesis and low cloud formation. But its climatic influence, on monthly and longer timescales, remains poorly understood. In particular, it is unclear how the warm current affects the free atmosphere above the marine atmospheric boundary layer. Here we consider the Gulf Stream's influence on the troposphere, using a combination of operational weather analyses, satellite observations and an atmospheric general circulation model. Our results reveal that the Gulf Stream affects the entire troposphere. In the marine boundary layer, atmospheric pressure adjustments to sharp sea surface temperature gradients lead to surface wind convergence, which anchors a narrow band of precipitation along the Gulf Stream. In this rain band, upward motion and cloud formation extend into the upper troposphere, as corroborated by the frequent occurrence of very low cloud-top temperatures. These mechanisms provide a pathway by which the Gulf Stream can affect the atmosphere locally, and possibly also in remote regions by forcing planetary waves. The identification of this pathway may have implications for our understanding of the processes involved in climate change, because the Gulf Stream is the upper limb of the Atlantic meridional overturning circulation, which has varied in strength in the past and is predicted to weaken in response to human-induced global warming in the future.

  13. Sea level differences across the Gulf Stream and Kuroshio extension

    NASA Technical Reports Server (NTRS)

    Zlotnicki, Victor

    1991-01-01

    The sea level differences between the Sargasso Sea and the slope waters across the Gulf Stream region, averaged between 73 and 61 deg W, and the comparable areas across the Kuroshio extension region, averaged between 143 and 156 deg E, were estimated using the Geosat altimeter data obtained between November 1986 and December 1988. The sea-level differences between the two regions showed a strong correlation between the northwest Atlantic and Pacific, dominated by annual cycles that peak in late-September to mid-October, with about 9 cm (the Gulf Stream region) and about 6.9 cm (Kuroshio region) amplitudes.

  14. Gulf Stream-Subtropical Gyre Properties Across Two Dansgaard-Oeschger Cycles

    NASA Astrophysics Data System (ADS)

    Hoogakker, B.; Chapman, M.; Elderfield, H.; McCave, I. N. N.; Gruetzner, J.

    2014-12-01

    It has been suggested that salinity increases in the subtropical gyre system may have pre-conditioned the North Atlantic Ocean for a rapid return to stronger overturning circulation and high-latitude warming following meltwater events during the Last Glacial period (Schmidt et al., 2006). Planktonic foraminifera oxygen isotopes (δ18O) measured on the surface dwelling Globigerinoides ruber show a positive gradient going from the Gulf Stream into the subtropical gyre during the Holocene as well as the Last Glacial Maximum (Keigwin, 2004). This gradient is due to decreasing temperatures, increasing salinity and a change from a summer to year round occurrence of G. ruber(Keigwin, 2004). During rapid climate oscillations between 54 and 46 ka of Marine Isotope Stage 3, including Heinrich ice-rafting event 5, this gradient may have been largely absent; G. ruber δ18O of ODP Site 1060 (subtropical gyre location) and ODP Site 1056 (Gulf Stream location) are virtually identical. Lower G. ruber δ18O that characterize the major warm DO interstadials 14 and 12 suggest a mainly summer occurrence of this species and indicate a more zonal and wider Gulf Stream influencing both ODP Sites. A large vertical δ18O gradient between shallow dwelling G. ruber and the deep dwelling species Globorotalia inflataat site 1056 is associated with strong summer stratification, supporting a Gulf Stream presence during these major interstadials. From about 51 ka until the end of Heinrich event 5 G. ruber δ18O is increased and the δ18O gradient between G. ruber and G. inflata is greatly reduced, suggesting a more year round occurrence of G. ruber and absence of summer stratification at site 1056, associated with subtropical gyre conditions. From this we infer that the Gulf Stream may have taken up a position nearer to the continental shelf during this cold period, where it may have been narrower with reduced transport.

  15. Wintertime air-sea interaction processes across the Gulf Stream

    NASA Astrophysics Data System (ADS)

    Bane, John M.; Osgood, Kenric E.

    1989-08-01

    Aircraft, buoy and satellite measurements have been used to study the wintertime air-sea interaction processes across the Gulf Stream during January 25-30, 1986. The turbulent flux regime in the marine atmospheric boundary layer exhibited considerable spatial and temporal variability during this 6-day period, which was related to both the evolution of the synoptic scale atmospheric conditions and the sea surface temperature (SST) field. During the pre-storm conditions prior to January 25, the spatial structure of the SST field played an important role in generating a shallow atmospheric frontal zone along the Gulf Stream front by causing differential heating of the marine atmospheric boundary layer over the stream versus over the cooler shelf waters. As this front moved shoreward on January 25, the warm, moist, maritime air flowing northwestward behind the front induced moderate ocean-to-atmosphere heat fluxes (˜300 W m-2 total heat flux measured over the core of the Gulf Stream). The subsequent outbreak of eastward flowing cold, dry, continental air over the ocean on January 27 and 28 generated high total heat fluxes (˜1060 W m-2 over the core of the Stream), as did a second, somewhat weaker outbreak which followed on January 30 (˜680 W2 over the core of the Stream). During each of these outbreaks, with air flowing from land out over the continental shelf, Gulf Stream and Sargasso Sea waters, the SST field again affected the spatial structure of the flux fields. The near-surface fluxes of both sensible and latent heat were found to be relatively low over the cool continental shelf waters, while higher fluxes were seen over the Gulf Stream and Sargasso Sea. Similar spatial structure was seen in the near-surface momentum flux values, but relative changes were typically smaller from one location to another on a particular day. The most noticeable responses of the Gulf Stream to these surface fluxes were the deepening of its mixed layer and a loss of upper layer

  16. A census of Gulf Stream rings, spring 1975

    NASA Technical Reports Server (NTRS)

    Richardson, P. L.; Worthington, L. V.; Cheney, R. E.

    1978-01-01

    During 1975 several shipboard expendable bathythermograph surveys plus satellite infrared imagery provided a nearly synoptic view of the distribution and number of Gulf Stream rings in the western North Atlantic. Twelve rings were identified; nine were cyclonic (cold core) rings and three were anticyclonic (warm core) rings. This is the largest number of rings ever observed during a short period of time (4 months). Evidence suggests that the mean movement of these rings was southwestward.

  17. Investigation of AIRSAR signatures of the Gulf Stream

    NASA Technical Reports Server (NTRS)

    Valenzuela, G. R.; Lee, J. S.; Schuler, D. L.; Marmorino, G. O.; Askari, F.; Hoppel, K.; Kaiser, J. A. C.; Keller, W. C.

    1992-01-01

    Extensive Airborne Synthetic Aperture Radar (AIRSAR) measurements were made on 20 July 1990 during the NRL Gulf Stream (GS) experiment which addressed a number of scientific questions relating to SAR imaging of the ocean surface in the presence of variable currents and the background thermohaline circulation. The nature of the electromagnetic (e.m.) backscatter from the North edge of the GS using polarimetric signatures and amplitude imagery from the AIRSAR data is addressed.

  18. Sea turtle distribution along the boundary of the Gulf Stream current off eastern Florida

    USGS Publications Warehouse

    Hoffman, W.; Fritts, T.H.

    1982-01-01

    Aerial surveys, out to 222 km off the east coast of central Florida during August 1980, revealed that marine turtles were distributed in a narrow zone west of the Gulf Stream. Of 255 loggerhead turtles, Caretta caretta, only three were observed east of the western boundary of the Gulf Stream. Radiometric thermometry revealed that the waters occupied by most Caretta were markedly cooler than the nearby waters of the Gulf Stream. Of 18 leatherback turtles, Dermochelys coriacea, all were seen west of the Gulf Stream in waters less than 70 m in depth. Marine turtles off eastern Florida are confined seasonally to nearshore waters west of the Gulf Stream. The records of Dermochelys in nearshore waters are in contrast with a deep water oceanic ecology often hypothesized for this species.

  19. Large-scale penetration of Gulf Stream water onto the continental shelf north of Cape Hatteras

    NASA Technical Reports Server (NTRS)

    Gawarkiewicz, Glen; Church, Thomas M.; Luther, George W., III; Ferdelman, Timothy G.; Caruso, Michael

    1992-01-01

    The presence of Gulf Stream water on the continental shelf as much as 60 km north of Cape Hatteras was observed during a hydrographic cruise in the summer of 1990. Gulf Stream water was concentrated at mid-depth between 10 and 30 m and penetrated the shelfbreak front which normally separates the shelf water from slope water and Gulf Stream water. Velocities of Gulf Stream water in the upper 110 m of the water column along the 1000 m isobath indicated a flow of 18 to 25 cm/s directed towards the northwest. Gulf Stream water on the shelf is considered to be associated with low values of fluorescence, transmissivity, and nutrient concentrations relative to adjacent shelf water.

  20. Remote sensing of Gulf Stream using GEOS-3 radar altimeter

    NASA Technical Reports Server (NTRS)

    Leitao, C. D.; Huang, N. E.; Parra, C. G.

    1978-01-01

    Radar altimeter measurements from the GEOS-3 satellite to the ocean surface indicated the presence of expected geostrophic height differences across the the Gulf Stream. Dynamic sea surface heights were found by both editing and filtering the raw sea surface heights and then referencing these processed data to a 5 minute x 5 minute geoid. Any trend between the processed data and the geoid was removed by subtracting out a linear fit to the residuals in the open ocean. The mean current velocity of 107 + or - 29 cm/sec calculated from the dynamic heights for all orbits corresponded with velocities obtained from hydrographic methods. Also, dynamic topographic maps were produced for August, September, and October 1975. Results pointed out limitations in the accuracy of the geoid, height anomaly deteriorations due to filtering, and lack of dense time and space distribution of measurements.

  1. Eighteen Degree Water formation within the Gulf Stream during CLIMODE

    NASA Astrophysics Data System (ADS)

    Joyce, Terrence M.; Thomas, Leif N.; Dewar, William K.; Girton, James B.

    2013-07-01

    Analysis of wintertime CLIMODE data for 2007 indicates that a substantial portion of new Eighteen Degree Water (EDW) is likely ventilated within the eastward flowing Gulf Stream (GS) between 67°W and 52°W longitudes, possibly exceeding that formed elsewhere in the northern Sargasso Sea. Use of some global air-sea interaction data sets applied to the study region for Feb/Mar of 2007 indicate that this winter may have been anomalously energetic in air-sea exchange compared to the mean of the prior 19 yr. The largest heat and freshwater fluxes found directly over the meandering warm core of the Gulf Stream are capable of removing most of the subtropical heat anomaly of the GS, but cross-frontal fluxes of salinity are required to account for the observed regional salinity structure. An isopycnal diffusivity of ˜100 m2 s-1 is inferred from the salinity balance. This mixing would also account for the observation that EDW formed in the GS is slightly fresher than that formed in northern Sargasso Sea. The lateral flux of heat across the GS north wall also acts to cool the resulting EDW water, but the heat balance for EDW production is largely determined from GS advection and air-sea fluxes, in contrast to salinity. Based on oxygen saturation data, we estimate that 1.8-3.0 Sv-yr of new EDW is formed in the GS for the winter of 2007. EDW originating from the GS is generated in a separate location from where it is accumulated in the northern Sargasso Sea. This manner of EDW formation will produce unique characteristics of EDW found in the northern Sargasso Sea: ones that differ in T/S properties from that formed south of the GS under the more traditional 1D, cooling-driven convection process.

  2. Fresh water balance of the Gulf Stream system in a regional model study

    NASA Astrophysics Data System (ADS)

    Gerdes, R.; Biastoch, A.; Redler, R.

    We investigate the dependence of surface fresh water fluxes in the Gulf Stream and North Atlantic Current (NAC) area on the position of the stream axis which is not well represented in most ocean models. To correct this shortcoming, strong unrealistic surface fresh water fluxes have to be applied that lead to an incorrect salt balance of the current system. The unrealistic surface fluxes required by the oceanic component may force flux adjustments and may cause fictitious long-term variability in coupled climate models. To identify the important points in the correct representation of the salt balance of the Gulf Stream a regional model of the northwestern part of the subtropical gyre has been set up. Sensitivity studies are made where the westward flow north of the Gulf Stream and its properties are varied. Increasing westward volume transport leads to a southward migration of the Gulf Stream separation point along the American coast. The salinity of the inflow is essential for realistic surface fresh water fluxes and the water mass distribution. The subpolar-subtropical connection is important in two ways: The deep dense flow from the deep water mass formation areas sets up the cyclonic circulation cell north of the Gulf Stream. The surface and mid depth flow of fresh water collected at high northern latitudes is mixed into the Gulf Stream and compensates for the net evaporation at the surface.

  3. On the recent destabilization of the Gulf Stream path downstream of Cape Hatteras

    NASA Astrophysics Data System (ADS)

    Andres, M.

    2016-09-01

    Mapped satellite altimetry reveals interannual variability in the position of initiation of Gulf Stream meanders downstream of Cape Hatteras. The longitude where the Gulf Stream begins meandering varies by 1500 km. There has been a general trend for the destabilization point to shift west, and 5 of the last 6 years had a Gulf Stream destabilization point upstream of the New England Seamounts. Independent in situ data suggest that this shift has increased both upper-ocean/deep-ocean interaction events at Line W and open-ocean/shelf interactions across the Middle Atlantic Bight (MAB) shelf break. Mooring data and along-track altimetry indicate a recent increase in the number of deep cyclones that stir Deep Western Boundary Current waters from the MAB slope into the deep interior. Temperature profiles from the Oleander Program suggest that recent enhanced warming of the MAB shelf may be related to shifts in the Gulf Stream's destabilization point.

  4. Prediction of silver hake distribution on the Northeast U.S. shelf based on the Gulf Stream path index

    NASA Astrophysics Data System (ADS)

    Davis, Xujing Jia; Joyce, Terrence M.; Kwon, Young-Oh

    2017-04-01

    Over the past 40 years, the distribution of silver hake on the Northeast U.S. shelf is found to be significantly correlated with changes in the latitude of Gulf Stream path. The correlation coefficient between the fall Gulf Stream position and the center of biomass of spring silver hake reaches 0.75 when the Gulf Stream leads the silver hake for 6 months. Based on this lead-lag relationship and low-frequency variability of Gulf Stream position with a dominant periodicity of 9-10 years, the Gulf Stream position is used as a predictor for the center of biomass of silver hake in linear autoregressive (AR) models. The goal of this study is then to optimize the AR model for the prediction of silver hake based on the observed changes in Gulf Stream position. Fall Gulf Stream position is first predicted out to 5 years using a 5th order AR model and the observed Gulf Stream position in preceding years. An optimization process is proposed to choose best AR coefficients based on a newly proposed combined skill parameter. Furthermore, the robustness of our Gulf Stream prediction is verified by comparing the observed Gulf Stream path index data from 2009 to 2012, which are not used for optimizing the AR model, and the predicted Gulf Stream path values for the same time period. We then use this predicted Gulf Stream position to further predict the center of biomass of silver hake in the subsequent spring. Three different methods are used and compared for the silver hake prediction. The predicted silver hake time series can explain as much as 69% of the variance of the observation for the 1st year prediction and 41% for the 5th year prediction. Our results indicate that including Gulf Stream as a predictor produces better prediction skills of silver hake center of biomass than the AR model prediction solely based on the observed silver hake time series.

  5. Passive Microwave Measurements of Salinity: The Gulf Stream Experiment

    NASA Technical Reports Server (NTRS)

    LeVine, D. M.; Koblinsky, C.; Haken, M.; Howden, S.; Bingham, F.; Hildebrand, Peter H. (Technical Monitor)

    2001-01-01

    Passive microwave sensors at L-band (1.4 GHz) operating from aircraft have demonstrated that salinity can be measured with sufficient accuracy (I psu) to be scientifically meaningful in coastal waters. However, measuring salinity in the open ocean presents unresolved issues largely because of the much greater accuracy (approximately 0.2 psu) required of global maps to be scientifically viable. The development of a satellite microwave instrument to make global measurements of SSS (Sea Surface Salinity) is the focus of a joint JPL/GSFC/NASA ocean research program called Aquarius. In the summer of 1999 a series of measurements called, The Gulf Stream Experiment, were conducted as part of research at the Goddard Space Flight Center to test the potential for passive microwave remote sensing of salinity in the open ocean. The measurements consisted of airborne microwave instruments together with ships and drifters for surface truth. The study area was a 200 km by 100 km rectangle about 250 km east of Delaware Bay between the continental shelf waters and north wall of the Gulf Stream. The primary passive instruments were the ESTAR radiometer (L-band, H-pol) and the SLFMR radiometer (L-band, V-pol). In addition, the instruments on the aircraft included a C-band radiometer (ACMR), an ocean wave scatterometer (ROWS) and an infrared radiometer (for surface temperature). These instruments were mounted on the NASA P-3 Orion aircraft. Sea surface measurements consisted of thermosalinograph data provided by the R/V Cape Henlopen and the MN Oleander, and data from salinity and temperature sensors on three surface drifters deployed from the R/V Cape Henlopen. The primary experiment period was August 26-September 2, 1999. During this period the salinity field within the study area consisted of a gradient on the order of 2-3 psu in the vicinity of the shelf break and a warm core ring with a gradient of 1-2 psu. Detailed maps were made with the airborne sensors on August 28 and 29 and

  6. The position of the gulf stream during quaternary glaciations.

    PubMed

    Keffer, T; Martinson, D G; Corliss, B H

    1988-07-22

    Ocean general circulation theories predict that the position of the boundary between subtropical and subpolar gyres (and therefore the position of the Gulf Stream-North Atlantic Current system and the subpolar-subtropical front) is set by the line of zero "Ekman pumping," where there is no convergence or divergence of water in the directly wind-forced surface layer of the ocean. In the present-day North Atlantic Ocean this line runs southwest to northeast, from off the Carolinas to off Ireland. However, during the last ice age (18,000 years ago) the subpolar-subtropical boundary ran more zonally, directly toward Gibraltar. A numerical atmospheric general circulation model indicates that the field of Ekman pumping 18,000 years ago was modified by the presence of a continental ice cap more than 3 kilometers thick such that the line of zero Ekman pumping overlaid the paleogyre boundary. These results demonstrate that the presence of a thick continental ice sheet could have caused changes in sea surface temperatures in the North Atlantic during Quaternary glaciations by altering wind patterns.

  7. Intrinsic low-frequency variability of the Gulf Stream

    NASA Astrophysics Data System (ADS)

    Quattrocchi, G.; Pierini, S.; Dijkstra, H. A.

    2012-03-01

    In this paper a process study aimed at analyzing the low-frequency variability of intrinsically oceanic origin of the Gulf Stream (GS) and GS extension (GSE) is presented. An eddy-permitting reduced-gravity nonlinear shallow water model is implemented in an idealized North Atlantic Ocean, with schematic boundaries including the essential geometric features of the coastline and a realistic zonal basin width at all latitudes. The forcing is provided by a time-independent climatological surface wind stress obtained from 41 years of monthly ECMWF fields. The model response yields strong intrinsic low-frequency fluctuations on the interannual to decadal time scales. The modelled time-averaged GS/GSE flows are found to exhibit several features that can also be deduced from satellite altimeter data, such as the Florida Current seaward deflection, the GS separation at Cape Hatteras, and the overall structure of the GSE. The intrinsic low-frequency variability yields two preferred states of the GSE differing in latitudinal location that also have their counterpart in the altimeter data. A preliminary analysis of the variability in terms of dynamical systems theory is carried out by using the lateral eddy viscosity as the control parameter. A complex transition sequence from a steady state to irregular low-frequency variability emerges, in which Hopf and global bifurcations can be identified.

  8. Seasonality of the submesoscale dynamics in the Gulf Stream region

    NASA Astrophysics Data System (ADS)

    Mensa, Jean Alberto; Garraffo, Zulema; Griffa, Annalisa; Özgökmen, Tamay Mehmet; Haza, Angelique; Veneziani, Milena

    2013-08-01

    Frontogenesis and frontal instabilities in the mixed layer are known to be important processes in the formation of submesoscale features. We study the seasonality of such processes in the Gulf Stream (GS) region. To approach this problem, a realistic simulation with the Hybrid Coordinate Ocean Model is integrated for 18 months at two horizontal resolutions: a high-resolution (1/48°) simulation able to resolve part of the submesoscale regime and the full range of mesoscale dynamics, and a coarser resolution (1/12°) case, in which submesoscales are not resolved. Results provide an insight into submesoscale dynamics in the complex GS region. A clear seasonal cycle is observed, with submesoscale features mostly present during winter. The submesoscale field is quantitatively characterized in terms of deviation from geostrophy and 2D dynamics. The limiting and controlling factor in the occurrence of submesoscales appears to be the depth of the mixed layer, which controls the reservoir of available potential energy available at the mesoscale fronts that are present most of the year. Atmospheric forcings are the main energy source behind submesoscale formation, but mostly indirectly through mixed layer deepening. The mixed layer instability scaling suggested in the (Fox-Kemper et al., J Phys Oceanogr 38:1145-1165, 2008) parametrization appears to hold, indicating that the parametrization is appropriate even in this complex and mesoscale dominated area.

  9. Contrasting responses of the extended Gulf Stream to severe winter forcing

    NASA Astrophysics Data System (ADS)

    Jacobs, Z.; Grist, J. P.; Marsh, R.; Josey, S. A.; Sinha, B.

    2015-12-01

    Changes in the path and strength of the extended Gulf Stream, downstream of Cape Hatteras, and the North Atlantic Current (GSNAC), are associated with strong wintertime air-sea interactions that can further influence the atmospheric storm track. The GSNAC response to anomalous air-sea heat fluxes in particular is dependent on the location of excess heat loss, in turn related to meteorological circumstances. Outbreaks of cold continental air may lead to excess cooling over the Sargasso Sea, as in 1976-77. Under these circumstances, the Gulf Stream may intensify through a steepening of cross-stream density gradients. An alternative scenario prevailed during the cold outbreak of 2013-14 where excess cooling occurred over the central subpolar gyre and may have influenced the extreme storminess experienced in western Europe. An objectively-analysed temperature and salinity product (EN4) is used to investigate the variability of the GSNAC. Temperature and salinity profiles are used to obtain geostrophic transport at selected GSNAC transects, confirming strong horizontal temperature gradients and a positive geostrophic velocity anomaly at 70oW in spring 1977, the strongest spring transport seen in the 1970s at this location. In addition to observations, an eddy-resolving model hindcast spanning 1970-2013, is used to further characterise GSNAC transport variability, allowing a fuller assessment of the relationship between the winter surface heat flux, end-of-winter mixed layer depth, subtropical mode water volume and GSNAC transports. Preliminary results reveal a significant negative correlation between the winter surface heat flux over the Sargasso Sea and the GSNAC transport in the following spring.

  10. The Gulf Stream Pathway and the Impacts of the Eddy-Driven Abyssal Circulation and the Deep Western Boundary Current

    DTIC Science & Technology

    2008-07-06

    Western North Atlantic Ocean Gulf Stream region ABSTRACT A hydrodynamic model of the subtropical Atlantic basin and the Intra-Americas Sea (9-47 N) is...Atlantic basin and the I ntra-Americas Sea (9 -47°N) is used to investigate the dynamics of Gulf Stream separation from the western boundary at Cape...between Cape Hatteras and the Grand Banks based on comparisons with Gulf Stream pathways from the satellite infrared (IR) sea surface temperature (SST

  11. The effect of Gulf Stream-induced baroclinicity on US East Coast winter cyclones

    SciTech Connect

    Cione, J.J.; Raman, S.; Pietrafesa, L.J. )

    1993-02-01

    Midlatitude cyclones develop off the Carolinas during winters and move north producing gale-force winds, ice, and heavy snow. It is believed that boundary-layer and air-sea interaction processes are very important during the development stages of these East Coast storms. The marine boundary layer (MBL) off the mid-Atlantic coastline is highly baroclinic due to the proximity of the Gulf Stream just offshore. Typical horizontal distances between the Wilmington coastline and the western edge of the Gulf Stream vary between 90 and 250 km annually, and this distance can deviate by over 30 km within a single week. While similar weekly Gulf Stream position standard deviations also exist at Cape Hatteras, the average annual distance to the Gulf Stream frontal zone is much smaller off Cape Hatteras, normally ranging between 30 and 100 km. This research investigates the low-level baroclinic conditions present prior to observed storm events. The examination of nine years of data on the Gulf Stream position and East Coast winter storms seems to indicate that the degree of low-level baroclinicity and modification existing prior to a cyclonic event may significantly affect the rate of cyclonic deepening off the mid-Atlantic coastline. Statistical analyses linking the observed surface-pressure decrease with both the Gulf Stream frontal location and the prestorm coastal baroclinic conditions are presented. These results quantitatively indicate that Gulf Stream-induced wintertime baroclinicity may significantly affect the regional intensification of East Coast winter cyclones. 20 refs., 9 figs., 1 tab.

  12. The gulf stream off the east coast of the United States

    NASA Astrophysics Data System (ADS)

    Bane, John M.

    1988-12-01

    Current and temperature data from a one-year-long instrument deployment in the region just northeast of Cape Hatteras have shown the oceanic variability to be, intense and quite complex. Changes in the position of the Gulf Stream’s path were observed to occur following cold core Gulf Stream passages through the area. The time between these changes was a few months. The Gulf Stream jet itself was seen to meander in a manner previously observed, as long as it was not undergoing a strong ring/stream interaction. Several isolated vortices progressed through the array, with the majority of them being in the submesoscale coherent vortex class. Two mid-depth, anticyclonic warm eddies progressed through the array. It is likely the two events were caused by two different transits of the same eddy. The deep waters below the main thermocline oscillated as topographic Rossby waves progressed through the array area.

  13. Gulf stream frontal eddy influence on productivity of the southeast U.S. continental shelf

    SciTech Connect

    Lee, T.M.; Yoder, J.; Atkinson, L.

    1991-01-01

    Weekly period meanders and eddies are persistent features of Gulf Stream frontal dynamics from Miami, FL, to Cape Hatteras, NC. Satellite imagery and moored current and temperature records reveal a spatial pattern of preferred regions for growth and decay of frontal disturbances. Growth regions occur off Miami, Cape Canaveral and Cape Fear due to baroclinic instability, and decay occurs in the confines of the Straits of Florida between Miami and Palm Beach, between 30{degrees} and 32{degrees}N where the Stream approaches the topographic feature known as the Charleston bump and between 34{degrees}N and Cape Hatteras. Eddy decay regions are associated with elongation of frontal features, offshore transport of momentum and heat and onshore transport of nutrients. Onshore transport of new nitrogen from the nutrient bearing strata beneath the Gulf Stream indicates that frontal eddies serve as a {open_quotes}nutrient pump{close_quotes} for the shelf. Annual carbon production on the shelf due to Gulf Stream input is estimated at 7{times}10{sup 12} g C year{sup -1} or about 7 million tons carbon per year. Seasonal carbon cycles are estimated for the outer, mid and inner shelf regions from Gulf Stream nutrient input, carbon production, and carbon export.

  14. Recent changes to the Gulf Stream causing widespread gas hydrate destabilization

    NASA Astrophysics Data System (ADS)

    Phrampus, B. J.; Hornbach, M. J.

    2012-12-01

    The Gulf Stream is an ocean current that modulates climate in the northern hemisphere by transporting warm waters from the Gulf of Mexico into the North Atlantic and Arctic Oceans (Lynch-Stieglitz et al., 1999, 2011). A changing Gulf Stream has the potential to thaw and convert hundreds of gigatons of frozen methane hydrate trapped below the seafloor into methane gas, increasing the risk of slope failure and methane release (Dickens, 2001; Kennett et al., 2003; Flemings et al., 2003; Archer et al., 2004). How the Gulf Stream changes with time and what effect these changes have on methane hydrate stability is unclear. Here, using seismic data combined with heat-flow models, we show that recent changes in intermediate ocean temperatures associated with the Gulf Stream are rapidly destabilizing methane hydrate along a broad swath of the North American Margin. The area of active hydrate destabilization covers as much as ~10,000 km^2 of the United States Eastern margin and occurs in a region prone to kilometer-scale slope failures. Previous hypothetical studies (Hornbach et al., 2004; Winguth et al., 2010) postulate that a 5 degC increase in intermediate ocean temperatures could release enough methane hydrate to explain extreme global warming events like the Late Palaeocene Thermal Maximum (LPTM) and trigger widespread ocean acidification (Biastock et al., 2011). Our analysis suggests that changes in Gulf Stream flow or temperature within the last ~5,000 years are warming the western North Atlantic Margin by as much as 8 degC and triggering contemporary methane hydrate destabilization along hundreds of kilometers that may continue for centuries. Other recent studies hypothesize similar ocean temperature changes may occur in the Arctic Ocean (Westbrook et al., 2009; Rajan et al., 2012). Thus, our estimate of 2.5 gigatons of destabilizing methane—or ~1% of that necessary to explain the LPTM— may represent only a fraction of the methane hydrate currently destabilizing

  15. Recent changes to the Gulf Stream causing widespread gas hydrate destabilization.

    PubMed

    Phrampus, Benjamin J; Hornbach, Matthew J

    2012-10-25

    The Gulf Stream is an ocean current that modulates climate in the Northern Hemisphere by transporting warm waters from the Gulf of Mexico into the North Atlantic and Arctic oceans. A changing Gulf Stream has the potential to thaw and convert hundreds of gigatonnes of frozen methane hydrate trapped below the sea floor into methane gas, increasing the risk of slope failure and methane release. How the Gulf Stream changes with time and what effect these changes have on methane hydrate stability is unclear. Here, using seismic data combined with thermal models, we show that recent changes in intermediate-depth ocean temperature associated with the Gulf Stream are rapidly destabilizing methane hydrate along a broad swathe of the North American margin. The area of active hydrate destabilization covers at least 10,000 square kilometres of the United States eastern margin, and occurs in a region prone to kilometre-scale slope failures. Previous hypothetical studies postulated that an increase of five degrees Celsius in intermediate-depth ocean temperatures could release enough methane to explain extreme global warming events like the Palaeocene-Eocene thermal maximum (PETM) and trigger widespread ocean acidification. Our analysis suggests that changes in Gulf Stream flow or temperature within the past 5,000 years or so are warming the western North Atlantic margin by up to eight degrees Celsius and are now triggering the destabilization of 2.5 gigatonnes of methane hydrate (about 0.2 per cent of that required to cause the PETM). This destabilization extends along hundreds of kilometres of the margin and may continue for centuries. It is unlikely that the western North Atlantic margin is the only area experiencing changing ocean currents; our estimate of 2.5 gigatonnes of destabilizing methane hydrate may therefore represent only a fraction of the methane hydrate currently destabilizing globally. The transport from ocean to atmosphere of any methane released--and thus its

  16. Gulf stream ground truth project - Results of the NRL airborne sensors

    NASA Technical Reports Server (NTRS)

    Mcclain, C. R.; Chen, D. T.; Hammond, D. L.

    1980-01-01

    Results of an airborne study of the waves in the Gulf Stream are presented. These results show that the active microwave sensors (high-flight radar and wind-wave radar) provide consistent and accurate estimates of significant wave height and surface wind speed, respectively. The correlation between the wave height measurements of the high-flight radar and a laser profilometer is excellent.

  17. Dynamical Evaluation of Ocean Models using the Gulf Stream as an Example

    DTIC Science & Technology

    2010-01-01

    1 Dynamical evaluation of ocean models using the Gulf Stream as an example Harley E. Hurlburt 1 , E. Joseph Metzger 1 , James G. Richman 1 , Eric...the organising committee, to Andreas Schiller and Chari Pattiaratchi for coordination of the curriculum and local venues, Nick D’Adamo for

  18. Internal-tide interactions with the Gulf Stream and Middle Atlantic Bight shelfbreak front

    NASA Astrophysics Data System (ADS)

    Kelly, Samuel M.; Lermusiaux, Pierre F. J.

    2016-08-01

    Internal tides in the Middle Atlantic Bight region are found to be noticeably influenced by the presence of the shelfbreak front and the Gulf Stream, using a combination of observations, equations, and data-driven model simulations. To identify the dominant interactions of these waves with subtidal flows, vertical-mode momentum and energy partial differential equations are derived for small-amplitude waves in a horizontally and vertically sheared mean flow and in a horizontally and vertically variable density field. First, the energy balances are examined in idealized simulations with mode-1 internal tides propagating across and along the Gulf Stream. Next, the fully nonlinear dynamics of regional tide-mean-flow interactions are simulated with a primitive-equation model, which incorporates realistic summer-mesoscale features and atmospheric forcing. The shelfbreak front, which has horizontally variable stratification, decreases topographic internal-tide generation by about 10% and alters the wavelengths and arrival times of locally generated mode-1 internal tides on the shelf and in the abyss. The (sub)mesoscale variability at the front and on the shelf, as well as the summer stratification itself, also alter internal-tide propagation. The Gulf Stream produces anomalous regions of O(20 mW m-2) mode-1 internal-tide energy-flux divergence, which are explained by tide-mean-flow terms in the mode-1 energy balance. Advection explains most tide-mean-flow interaction, suggesting that geometric wave theory explains mode-1 reflection and refraction at the Gulf Stream. Geometric theory predicts that offshore-propagating mode-1 internal tides that strike the Gulf Stream at oblique angles (more than thirty degrees from normal) are reflected back to the coastal ocean, preventing their radiation into the central North Atlantic.

  19. Estimating occurrence and detection probabilities for stream-breeding salamanders in the Gulf Coastal Plain

    USGS Publications Warehouse

    Lamb, Jennifer Y.; Waddle, J. Hardin; Qualls, Carl P.

    2017-01-01

    Large gaps exist in our knowledge of the ecology of stream-breeding plethodontid salamanders in the Gulf Coastal Plain. Data describing where these salamanders are likely to occur along environmental gradients, as well as their likelihood of detection, are important for the prevention and management of amphibian declines. We used presence/absence data from leaf litter bag surveys and a hierarchical Bayesian multispecies single-season occupancy model to estimate the occurrence of five species of plethodontids across reaches in headwater streams in the Gulf Coastal Plain. Average detection probabilities were high (range = 0.432–0.942) and unaffected by sampling covariates specific to the use of litter bags (i.e., bag submergence, sampling season, in-stream cover). Estimates of occurrence probabilities differed substantially between species (range = 0.092–0.703) and were influenced by the size of the upstream drainage area and by the maximum proportion of the reach that dried. The effects of these two factors were not equivalent across species. Our results demonstrate that hierarchical multispecies models successfully estimate occurrence parameters for both rare and common stream-breeding plethodontids. The resulting models clarify how species are distributed within stream networks, and they provide baseline values that will be useful in evaluating the conservation statuses of plethodontid species within lotic systems in the Gulf Coastal Plain.

  20. Gulf Stream marine hydrokinetic energy resource characterization off Cape Hatteras, North Carolina

    NASA Astrophysics Data System (ADS)

    Muglia, M.; He, R.; Lowcher, C.; Bane, J.; Gong, Y.; Taylor, P.

    2015-12-01

    The Gulf Stream off North Carolina has current velocities that approach 3 m/s and an average volume transport of 90 Sv (1 Sv= 106 m3/s) off of Cape Hatteras, making it the most abundant MHK (Marine Hydrokinetic Energy) resource for the state. Resource availability at a specific location depends primarily on the variability in Gulf Stream position, which is least offshore of Cape Hatteras after the stream exits the Florida Straits. Proximity to land and high current velocities in relatively shallow waters on the shelf slope make this an optimal location to quantify the MHK energy resource for NC. 3.5 years of current measurements beginning in August of 2013 from a moored 150 kHz ADCP (Acoustic Doppler Current Profiler) at an optimal location for energy extraction quantify the available energy resource and its variability, and establish the skill of a Mid-Atlantic Bight and South Atlantic Bight Regional Ocean Model in predicting the MHK energy resource. The model agrees well with long-term observed current averages and with weekly to monthly fluctuations in the current speeds. Model and observations over the first 9 months of the ADCP deployment period both averaged 1.15 m/s thirty meters below the surface. The model under estimates observed current speeds for the higher frequency current fluctuations of days to weeks. Comparisons between the model and ADCP observed currents, and velocity derived power density over the entire 3.5 years of observations demonstrate the significant inter-annual variability in power density. Shipboard 300 kHz ADCP cross-stream transects and hourly surface currents measurements off Cape Hatteras from a network of land based HF (high frequency) radars further quantify available MHK energy and assess model skill. Cross-stream transects were made with a vessel-mounted 300 kHz ADCP on a line from the 100-1000m isobaths, and measured currents in the top 100m. These measurements demonstrate the variability in the resource with water depth, and

  1. Gulf Stream frontal eddy influence on productivity of the southeast U.S. continental shelf

    NASA Astrophysics Data System (ADS)

    Lee, Thomas N.; Yoder, James A.; Atkinson, Larry P.

    1991-12-01

    Weekly period meanders and eddies are persistent features of Gulf Stream frontal dynamics from Miami, Florida, to Cape Hatteras, North Carolina. Satellite imagery and moored current and temperature records reveal a spatial pattern of preferred regions for growth and decay of frontal disturbances. Growth regions occur off Miami, Cape Canaveral, and Cape Fear due to baroclinic instability, and decay occurs in the confines of the Straits of Florida between Miami and Palm Beach, between 30° and 32°N where the stream approaches the topographic feature known as the Charleston bump and between 33°N and Cape Hatteras. Eddy decay regions are associated with elongation of frontal features, offshore transport of momentum and heat, and onshore transport of nutrients. Onshore transport of new nitrogen from the nutrient-bearing strata beneath the Gulf Stream indicates that frontal eddies serve as a "nutrient pump" for the shelf. New nitrogen flux to the shelf due to Gulf Stream input could support new production of 7.4×1012 g C yr-1 or about 8 million tons carbon per year if all nitrate were utilized. Calculations indicate that approximately 70% of this potential new production is realized, yielding an annual new production for the outer shelf of 4.3×1012 g C.

  2. The branching of the Gulf Stream southeast of the Grand Banks

    NASA Astrophysics Data System (ADS)

    Krauss, W.; KäSe, R. H.; Hinrichsen, H.-H.

    1990-08-01

    During March-April 1987, 101 hydrographic stations were occupied on three sections spanning a triangle between the Azores (Faial), the southern tip of the Grand Banks of Newfoundland, and Bermuda. Information on the near-surface processes in the interior of the triangle were obtained from 32 satellite-tracked buoys deployed during the cruise and a composite infrared image based on cloud-free NOAA 9 data during April 1987. The data were combined to analyze the eddy field and the branching of the Gulf Stream into the North Atlantic Current and the Azores Current. Calculations of mass transports through the legs of the triangle gave a total of 46 Sv supplied by the Gulf Stream, 31 Sv of which left the area as the North Atlantic Current and westwind drift north of the Azores. The remaining 14 Sv continued towards east-southeast as the Azores Current and southern recirculation. Additional conductivity-temperature-depth stations from a cruise in April 1986 into the same area allowed also study of the large-scale circulation within that triangle in deeper layers. The Azores Current appears as a baroclinic stream which reaches down to approximately 1000 m. Intensive mixing was observed at the continental slope of Newfoundland between water of the Labrador Current and the Gulf Stream (mixed water). Owing to cabbeling and consecutive convective mixing, this water penetrates down to 2000 m depth and creates horizontal density gradients to the surrounding Gulf Stream water, which intensifies the North Atlantic Current. This process is considered to be an important energy source for this current.

  3. Temporal variation of meandering intensity and domain-wide lateral oscillations of the Gulf Stream

    NASA Technical Reports Server (NTRS)

    Lee, Tong; Cornillon, Peter

    1995-01-01

    The path of the Gulf Stream exhibits two modes of variability: wavelike spatial meanders associated with instability processes and large-sale lateral shifts of the path presumably due to atmospheric forcing. The objectives of this study are to examine the temporal variation of the intensity of spatial meandering in the stream, to characterize large-scale lateral oscillations in the stream's path, and to study the correlation betwen these two dynamically distinct modes of variability. The data used for this analysis are path displacemets ofthe Gulf Stream between 75 deg and 60 deg W obtained from AVHRR-derived (Advanced Very High Resolution Radiometer) infrared images for the period April 1982 through December 1989. Meandering intensity, measured by the spatial root-mean-sqaure displacement of the stream path, displays a 9-month dominant periodicity which is persistent through the study period. The 9-month fluctuation in meandering intensity may be related to the interaction of Rosseby waves with the stream. Interannual variation of meandering intensity is also found to be significant, with meandering being mich more intense during 1985 than it was in 1987. Annual variation, however,is weak and not well-defined.The spatially averaged position of the stream, which reflects nonmeandering large-scale lateral oscillations of the stream path, is dominated by an annual cycle. On average, the mean position is farthest north in November and farthest south in April. The first empirical orthogonal function mode of the space-time path displacements represents lateral oscillatins that are in-phase over the space-time domain. Interannual oscillations are also observed and are found to be weaker than the annual oscillation. The eigenvalue of the first mode indicates that about 21.5% of the total space-time variability of the stream path can be attibuted to domain-wide lateral oscillation. The correlation between meandering intensity and domain-wide lateral oscillations is very

  4. Gulf Stream Power Characteristics near Cape Hatteras; Regional Model vs. Direct Current Observations

    NASA Astrophysics Data System (ADS)

    Lowcher, C.; Bane, J.; Gong, Y.; He, R.; Muglia, M.

    2014-12-01

    The Gulf Stream has current velocities reaching approximately 2 meters per second, which distinguish it as a potential source of marine hydrokinetic (MHK) energy. The upper continental slope off Cape Hatteras is a desirable area for development of offshore renewable energy because of the closeness of the Gulf Stream to the shelf edge and its minimal meanderings there. Using data from a moored 150-kHz ADCP and from the Mid-Atlantic Bight and South Atlantic Bight (MABSAB) ocean circulation model, MHK power characteristics have been computed for this area. These calculations quantify the Gulf Stream power resource and its temporal and spatial variations. During August 2013 - April 2014 at the moored ADCP site 30 meters below the surface and within the Stream's cyclonic shear zone, a comparison of the ADCP and MABSAB model reveals that the average current speeds from the two sources are nearly identical and have a magnitude of 1.15 m/s. A comparison for the same time period was made for Betz power, which yielded an observed average of 0.8 kW/m2 and a model average of 0.7 kW/m2, a difference of about 13%. The model has shown to be more conservative than the ADCP in its computation of current speed and Betz power, and it shows somewhat less variability than the ADCP in directionality of the Stream. Additionally, model data have been used to calculate annual average vector velocities and yearly Betz power averages for a number of years, and at various locations over the NC continental slope. These results depict the variation of the Stream's position along the NC coastline over the most recent years, and show that yearly averaged Betz power at a given location has significant inter-annual variations, with average power during one year being nearly four times greater than in another year.

  5. Gulf stream velocity structure through combined inversion of hydrographic and acoustic Doppler data

    NASA Technical Reports Server (NTRS)

    Pierce, S. D.

    1986-01-01

    Near-surface velocities from an acoustic Doppler instrument are used in conjunction with CTD/O2 data to produce estimates of the absolute flow field off Cape Hatteras. The data set consists of two transects across the Gulf Stream made by the R/V Endeavor cruise EN88 in August 1982. An inverse procedure is applied which makes use of both the acoustic Doppler data and property conservation constraints. Velocity sections at approximately 73 deg. W and 71 deg. W are presented with formal errors of 1-2 cm/s. The net Gulf Stream transports are estimated to be 116 + or - 2 Sv across the south leg and 161 + or - 4 Sv across the north. A Deep Western Boundary Current transport of 4 + or - 1 Sv is also estimated. While these values do not necessarily represent the mean, they are accurate estimates of the synoptic flow field in the region.

  6. Automatic Description of the Gulf Stream from IR Images Using Neural Networks.

    DTIC Science & Technology

    1990-01-01

    IIII I I I b TSPIE-The International Society for Optical Engineering Reprinted from Applications of Artificial Neural Networks 18-20 April 1990 Orlando...Telephone 206/676-3290. Automatic description of the Gulf Stream from IR images using neural networks Matthew Lybanon Naval Oceanographic and Atmospheric...nodes. Again, learning was by back SPIE Vol 1294 Applications of Artificial Neural Networks (1990) / 225 propagation. The training set consisted of

  7. Submesoscale streamers exchange water on the north wall of the Gulf Stream

    NASA Astrophysics Data System (ADS)

    Klymak, Jody M.; Shearman, R. Kipp; Gula, Jonathan; Lee, Craig M.; D'Asaro, Eric A.; Thomas, Leif N.; Harcourt, Ramsey R.; Shcherbina, Andrey Y.; Sundermeyer, Miles A.; Molemaker, Jeroen; McWilliams, James C.

    2016-02-01

    The Gulf Stream is a major conduit of warm surface water from the tropics to the subpolar North Atlantic. Here we observe and simulate a submesoscale (<20 km) mechanism by which the Gulf Stream exchanges water with subpolar water to the north. Along isopycnals, the front has a sharp compensated temperature-salinity contrast, with distinct mixed water between the two water masses 2 and 4 km wide. This mixed water does not increase downstream despite substantial energy available for mixing. A series of streamers detrain this water at the crest of meanders. Subpolar water replaces the mixed water and resharpens the front. The water mass exchange accounts for a northward flux of salt of 0.5-2.5 psu m2 s-1, (large-scale diffusivity O (100 m2 s-1)). This is similar to bulk-scale flux estimates of 1.2 psu m2 s-1 and supplies fresher water to the Gulf Stream required for the production of 18° subtropical mode water.

  8. Structure, transport, and vertical coherence of the Gulf Stream from the Straits of Florida to the Southeast Newfoundland Ridge

    NASA Astrophysics Data System (ADS)

    Meinen, Christopher S.; Luther, Douglas S.

    2016-05-01

    Data from three independent and extensive field programs in the Straits of Florida, the Mid-Atlantic Bight, and near the Southeast Newfoundland Ridge are reanalyzed and compared with results from other historical studies to highlight the downstream evolution of several characteristics of the Gulf Stream's mean flow and variability. The three locations represent distinct dynamical regimes: a tightly confined jet in a channel; a freely meandering jet; and a topographically controlled jet on a boundary. Despite these differing dynamical regimes, the Gulf Stream in these areas exhibits many similarities. There are also anticipated and important differences, such as the loss of the warm core of the current by 42°N and the decrease in the cross-frontal gradient of potential vorticity as the current flows northward. As the Gulf Stream evolves it undergoes major changes in transport, both in magnitude and structure. The rate of inflow up to 60°W and outflow thereafter are generally uniform, but do exhibit some remarkable short-scale variations. As the Gulf Stream flows northward the vertical coherence of the flow changes, with the Florida Current and North Atlantic Current segments of the Gulf Stream exhibiting distinct upper and deep flows that are incoherent, while in the Mid-Atlantic Bight the Gulf Stream exhibits flows in three layers each of which tends to be incoherent with the other layers at most periods. These coherence characteristics are exhibited in both Eulerian and stream coordinates. The observed lack of vertical coherence indicates that great caution must be exercised in interpreting proxies for Gulf Stream structure and flow from vertically-limited or remote observations.

  9. Structure, transport, and vertical coherence of the Gulf Stream from the Straits of Florida to the Southeast Newfoundland Ridge

    NASA Astrophysics Data System (ADS)

    Meinen, Christopher S.; Luther, Douglas S.

    2016-06-01

    Data from three independent and extensive field programs in the Straits of Florida, the Mid-Atlantic Bight, and near the Southeast Newfoundland Ridge are reanalyzed and compared with results from other historical studies to highlight the downstream evolution of several characteristics of the Gulf Stream's mean flow and variability. The three locations represent distinct dynamical regimes: a tightly confined jet in a channel; a freely meandering jet; and a topographically controlled jet on a boundary. Despite these differing dynamical regimes, the Gulf Stream in these areas exhibits many similarities. There are also anticipated and important differences, such as the loss of the warm core of the current by 42°N and the decrease in the cross-frontal gradient of potential vorticity as the current flows northward. As the Gulf Stream evolves it undergoes major changes in transport, both in magnitude and structure. The rate of inflow up to 60°W and outflow thereafter are generally uniform, but do exhibit some remarkable short-scale variations. As the Gulf Stream flows northward the vertical coherence of the flow changes, with the Florida Current and North Atlantic Current segments of the Gulf Stream exhibiting distinct upper and deep flows that are incoherent, while in the Mid-Atlantic Bight the Gulf Stream exhibits flows in three layers each of which tends to be incoherent with the other layers at most periods. These coherence characteristics are exhibited in both Eulerian and stream coordinates. The observed lack of vertical coherence indicates that great caution must be exercised in interpreting proxies for Gulf Stream structure and flow from vertically-limited or remote observations.

  10. Gulfcasting: Dynamical Forecast Experiments for Gulf Stream Rings and Meanders

    DTIC Science & Technology

    1987-08-01

    36.2N 66.8W. Due to equipment failure , very important AXBTs were missed near 39.5N 68.5W at the location of the ring-stream interaction. May 29...slightly to the north of the IR data. A warm ring was located at 39.8N 66.7W and a cold ring at 36.ON 66.8W. Equipment failure caused the position of a...problems and equipment failure made it impossible to determine the status of the possible cold ring at 35.5N 70.5W. 2.5.3.3 Model run Central forecast C3

  11. Effect of stream channel size on the delivery of nitrogen to the Gulf of Mexico

    USGS Publications Warehouse

    Alexander, R.B.; Smith, R.A.; Schwarz, G.E.

    2000-01-01

    An increase in the flux of nitrogen from the Mississippi river during the latter half of the twentieth century has caused eutrophication and chronic seasonal hypoxia in the shallow waters of the Louisiana shelf in the northern Gulf of Mexico. This has led to reductions in species diversity, mortality of benthic communities and stress in fishery resources. There is evidence for a predominantly anthropogenic origin of the increased nitrogen flux, but the location of the most significant sources in the Mississippi basin responsible for the delivery of nitrogen to the Gulf of Mexico have not been clearly identified, because the parameters influencing nitrogen-loss rates in rivers are not well known. Here we present an analysis of data from 374 US monitoring stations, including 123 along the six largest tributaries to the Mississippi, that shows a rapid decline in the average first-order rate of nitrogen loss with channel size-from 0.45 day-1 in small streams to 0.005 day-1 in the Mississippi river. Using stream depth as an explanatory variable, our estimates of nitrogen-loss rates agreed with values from earlier studies. We conclude that the proximity of sources to large streams and rivers is an important determinant of nitrogen delivery to the estuary in the Mississippi basin, and possibly also in other large river basins.

  12. The Gulf Stream pathway and the impacts of the eddy-driven abyssal circulation and the Deep Western Boundary Current

    NASA Astrophysics Data System (ADS)

    Hurlburt, Harley E.; Hogan, Patrick J.

    2008-08-01

    A hydrodynamic model of the subtropical Atlantic basin and the Intra-Americas Sea (9-47°N) is used to investigate the dynamics of Gulf Stream separation from the western boundary at Cape Hatteras and its mean pathway to the Grand Banks. The model has five isopycnal Lagrangian layers in the vertical and allows realistic boundary geometry, bathymetry, wind forcing, and a meridional overturning circulation (MOC), the latter specified via ports in the northern and southern boundaries. The northward upper ocean branch of the MOC (14 Sv) was always included but the southward Deep Western Boundary Current (DWBC) was excluded in some simulations, allowing investigation of the impacts of the DWBC and the eddy-driven mean abyssal circulation on Gulf Stream separation from the western boundary. The result is resolution dependent with the DWBC playing a crucial role in Gulf Stream separation at 1/16° resolution but with the eddy-driven abyssal circulation alone sufficient to obtain accurate separation at 1/32° resolution and a realistic pathway from Cape Hatteras to the Grand Banks with minimal DWBC impact except southeast of the Grand Banks. The separation from the western boundary is particularly sensitive to the strength of the eddy-driven abyssal circulation. Farther to the east, between 68°W and the Grand Banks, all of the 1/16° and 1/32° simulations with realistic topography (with or without a DWBC) gave similar generally realistic mean pathways with clear impacts of the topographically constrained eddy-driven abyssal circulation versus very unrealistic Gulf Stream pathways between Cape Hatteras and the Grand Banks from otherwise identical simulations run with a flat bottom, in reduced-gravity mode, or with 1/8° resolution and realistic topography. The model is realistic enough to allow detailed model-data comparisons and a detailed investigation of Gulf Stream dynamics. The corresponding linear solution with a Sverdrup interior and Munk viscous western boundary

  13. Strong impacts of the Gulf Stream anomalies on the large-scale atmospheric state

    NASA Astrophysics Data System (ADS)

    Nakamura, Mototaka; Yamane, Shozo

    2010-05-01

    Geological data and climate simulation models suggest that the North Atlantic Deep Water (NADW) that plays a critical role in the global thermohaline circulation may have gone through major fluctuations in the past, bringing with them major climatic anomalies around the basin. A future collapse of the NADW formation has been a concern, as theories and climate simulation models suggest freshening of the North Atlantic as a result of the carbon dioxide increase in the atmosphere. Meanwhile, attempts to find strong impacts of SST anomalies in the North Atlantic on the large-scale atmospheric state in the data and simulation experiments had not been very successful, casting some doubt on the extent to which the thermohaline circulation fluctuations affect the Northern Hemispheric climate. In an attempt to find evidence of strong impacts of the SST anomalies along the Gulf Stream on the regional and Northern Hemispheric climates, we analyzed the ERA40 reanalysis data and Hadley Centre SST data with the near-surface baroclinicity as the key parameter that connects the extra-tropical SST anomalies with the large-scale atmospheric anomalies. We first calculated EOFs of the near-surface baroclinicity for the domain that covers the North Atlantic storm track for each month. We then compiled anomaly composites of the SST, net surface heat flux, and various atmospheric fields for the positive and negative phases of the first two EOFs for each month. We also compiled composites of the anomalies for the preceding and following months for the first two EOFs. From the above diagnoses, we identified strong impacts of the SST anomalies in the vicinity of the Gulf Stream on the large-scale atmospheric state, mostly in cold months. The scale of the atmospheric anomalies generated is very large, on the order of 1000km to 10000km, spanning the entire hemisphere. Roughly speaking, there are two patterns of atmospheric anomalies. One is characterized by a meridional shift in the

  14. Polarization and wavelength diversities of Gulf Stream fronts imaged by AIRSAR

    NASA Technical Reports Server (NTRS)

    Lee, J. S.; Jansen, R. W.; Marmorino, G. O.; Chubb, S. R.

    1995-01-01

    During the 1990 Gulf Stream Experiment, NASA/JPL AIRSAR imaged the north edge of the Gulf Stream near the coast of Virginia. Simultaneous in-situ measurements of currents, temperatures, salinities, etc. were made for several crossings of the north edge by the R/V Cape Henlopen. Measurements identified two fronts with shearing and converging flows. The polarimetric SAR images from the fronts showed two bright linear features. One of them corresponds to the temperature front, which separated the warm Gulf Stream water to the south from a cool, freshwater filament to the north. The other line, located about 8 km north of the temperature front, is believed to correspond to the velocity front between the filament and the slope water. At these fronts, wave-current interactions produced narrow bands of steep and breaking waves manifesting higher radar returns in polarimetric SAR images. In general, our AIRSAR imagery shows that the signal-to-clutter ratio of radar cross sections for the temperature front is higher than that of the velocity front. In this paper, we study the polarization and wavelength diversities of radar response of these two fronts using the P-, L-, and C-Band Polarimetric SAR data. The north-south flight path of the AIRSAR crossed the temperature front several times and provided valuable data for analysis. Three individual passes are investigated. We found that for the temperature front, the cross-pol (HV) responses are much higher than co-pol responses (VV and HH), and that P-Band HV has the highest signal to clutter ratio. For the velocity front, the ratio is the strongest in P-Band VV, and it is indistinguishable for all polarizations in C-Band. The radar cross sections for all three polarization (HH, HV, and VV) and for all three bands are modelled using an ocean wave model and a composite Bragg scattering model. In our initial investigations, the theoretical model agrees qualitatively with the AIRSAR observations.

  15. Observation of the surface circulation in a Gulf Stream frontal perturbation

    SciTech Connect

    Vukovich, F.M.; Maul, G.A.

    1983-07-01

    In the period of 3--16 June 1979, a satellite-tracked, free-drifting buoy passed through a Gulf Stream frontal perturbation and was entrained into a warm filament on the shoreward side of the perturbation. Significant speed convergence was noted as the buoy passed through the perturbation and approached the counterclockwise turn into the warm filament. In the warm filament, the buoy drifted to the southwest at speeds of about 0.1 to 0.3 m/sec. Eventually, the buoy drifted out of the filament and went westward in an apparent response to wind-induced surface drift.

  16. Dynamical Evaluation of Ocean Models Using the Gulf Stream as an Example

    DTIC Science & Technology

    2012-02-10

    Laplacian coefficient of isopycnal eddy viscosity is A= 20 (10) m2/s for the 1/16° (1/32°) simulations. The SSH contour interval is 8 cm. The mean Gulf...Stream as an Example 561 DWBC 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 ••! I r—i r r (in cm) NO DWBC 76W 74W 72W...pathway in eddy-resolving basin-scale OGCMs with thermodynamics and higher vertical reso- lution ( 20 -50 layers or levels) than the 5 layers used in

  17. Gulf Stream variability in western North Atlantic off Cape Lookout, North Carolina

    NASA Astrophysics Data System (ADS)

    Pedersen, A. B.; Seidenkrantz, M.-S.; Mienis, F.; Fischel, A.; Frank, N.; Hebbeln, D.

    2012-04-01

    Cold-water coral mounds are common on the SE slope of the US (SEUS) from Florida to Cape Hatteras between depths of 400-600 m. The coral areas lie in the vicinity of the Gulf Stream, which is characterized by strong currents transporting relatively warm water northwards along the SEUS slope. Thus far little is known about the environmental conditions inside the SEUS coral communities and particularly the effects of the nearby Gulf Stream. Near Cape Lookout (North Carolina margin) cold-water corals have formed mound structures, which have a teardrop shape with a sediment tail at the lee side of the mounds, indicating the presence of a strong uni-directional current. The mounds were found to be partly covered with living Lophelia pertusa colonies and partly with sediment and dead coral framework. A 3.4 m long piston core was collected in 2010 during a cruise with the RV Pelagia. This pistoncore was used to determine the changes of the current strength in time in the study area. Different measurements including foraminiferal counts, stable oxygen and carbon isotopes, XRF and magnetic susceptibility were carried out to determine the changes in current strength in the area. Furthermore, cold-water coral fragments were dated with U/Th and foraminifera from the same depth intervals were dated with C14. Datings show that all corals have the same age around 5500 years. However, the sediment in between the corals showed ages ranging between 4700 and 13000 years. Based on the foraminifera data three zones could be observed in the core. Zone 1 ranges between 13000 and 10000 years, zone 2 between 10000-7200 years and zone 3 between 7200-4700 years. These zones all show the gradual onshore movement of the Gulf Stream, that can be related to a rapid rise in sea level as a response to the last deglaciation. This movement has gradually widened the band of the Gulf Stream, thereby compressing the surface and deeper water masses. The strength of the current decreased when fresh water

  18. Physical characteristics of the Gulf Stream as an indicator of the quality of large-scale circulation modeling

    NASA Astrophysics Data System (ADS)

    Sarkisyan, A. S.; Nikitin, O. P.; Lebedev, K. V.

    2016-12-01

    The general idea of this work is to show that the efficiency of modeling boundary currents (compared to the results of observations) can serve as an indicator of correctness for the modeling of the entire large-scale ocean circulation. The results of calculation of the mean surface currents in the Gulf Stream area based on direct measurements from drifters are presented together with the results of numerical modeling of variability of the Gulf Stream transport at 33°N over the period 2005-2014 based on data from Argo profiling buoys.

  19. Airborne dual laser excitation and mapping of phytoplankton photopigments in a Gulf Stream Warm Core Ring

    NASA Technical Reports Server (NTRS)

    Hoge, F. E.; Swift, R. N.

    1983-01-01

    Utilization of a two-color airborne lidar system in the systematic study of a major oceanographic feature is reported here for the first time. An excimer pumped dye laser was optically and electronically integrated into the NASA Airborne Oceanographic Lidar for simultaneous use with a frequency doubled Nd:YAG laser. The output beams exit the laser system along parallel paths after being produced on an alternating pulse basis at a combined rate of 12.5 pps. Results are presented for missions flown over a Gulf Stream Warm Core Ring (WCR) as well as over shelf, slope, Gulf Stream, and Sargasso Sea waters. From the airborne data a high coherence is shown between the two-color chlorophyll a data and between the Nd:YAG chlorophyll a and phycoerythrin responses within each of these water masses. However, distinct differences in the response patterns of these photopigments are shown to exist between the differing water masses. At certain of the boundaries separating the water masses a sharp transition is seen to occur, while at others a wider transition zone was observed in which the correlation between the photopigments appears to degrade.

  20. Objective analysis of the Gulf Stream thermal front: methods and accuracy. Technical report

    SciTech Connect

    Tracey, K.L.; Friedlander, A.I.; Watts, R.

    1987-12-01

    The objective-analysis (OA) technique was adapted by Watts and Tracey in order to map the thermal frontal zone of the Gulf Stream. Here, the authors test the robustness of the adapted OA technique to the selection of four control parameters: mean field, standard deviation field, correlation function, and decimation time. Output OA maps of the thermocline depth are most affected by the choice of mean field, with the most-realistic results produced using a time-averaged mean. The choice of the space-time correlation function has a large influence on the size of the estimated error fields, which are associated with the OA maps. The smallest errors occur using the analytic function based on 4 years of inverted echo sounder data collected in the same region of the Gulf Stream. Variations in the selection of the standard deviation field and decimation time have little effect on the output OA maps. Accuracy of the output OA maps is determined by comparing them with independent measurements of the thermal field. Two cases are evaluated: standard maps and high-temporal-resolution maps, with decimation times of 2 days and 1 day, respectively. Standard deviations (STD) between the standard maps at the 15% estimated error level and the XBTs (AXBTs) are determined to be 47-53 m. Comparisons of the high-temporal-resolution maps at the 20% error level with the XBTs (AXBTs) give STD differences of 47 m.

  1. Significant bed elevation changes related to Gulf Stream dynamics on the South Carolina continental shelf

    USGS Publications Warehouse

    Gelfenbaum, G.; Noble, M.

    1993-01-01

    Photographs of the seabed taken from an instrumented bottom tripod located approximately 100 km east of Charleston, South Carolina, reveal bed elevation changes of over 20 cm between July and November 1978. The tripod was in 85 m of water and was equipped with two current meters at 38.7 and 100 cm from the bed, a pressure sensor, a transmissometer, which fouled early during the deployment, a temperature sensor and a camera. The sediment under the tripod was composed of poorly sorted sand, some shell debris and numerous small biological tubes. Bed roughness varied throughout the deployment from biologically-produced mounds (2-5 cm high and 5-20 cm diameter) to streaks to a smooth bed, depending upon the frequency and magnitude of the sediment transporting events. Even though these events were common, especially during the later part of the deployment, the bed was rarely rippled, and there was no evidence of large bedforms such as dunes or sand waves migrating through the field of view of the camera. Photographs did clearly show, however, a gradual net deposition of the bed of nearly 20 cm, followed by erosion of approximately 5 cm. The flow field near the bed was dominated by sub-tidal period currents. Hourly-averaged currents at 100 cm from the bed typically varied between 10 and 30 cm s-1 and occasionally were as high as 60 cm s-1. The large flow events were predominantly toward the southwest along the shelf in the opposite direction of the northeast flowing Gulf Stream. The cross-shore component of the flow near the bed was predominantly directed offshore due to a local topographic steering effect. Current, temperature and satellite data suggest that the largest flow events were associated with the advection of Gulf Stream filaments past the tripod. Erosion events, as seen from the photographs, were highly correlated with the passage of these Gulf Stream filaments past the tripod. Gradual deposition of sediment, which occurred during the first half of the

  2. Estimating uncertainties on a Gulf Stream mixed-layer heat budget from stochastic modeling

    NASA Astrophysics Data System (ADS)

    Ayoub, Nadia K.; Lucas, Marc; De Mey, Pierre

    2015-10-01

    This study aims to explore the robustness of the mixed-layer heat budget as estimated from an eddy-permitting model with respect to uncertainties in atmospheric forcing. We illustrate how statistics from an ensemble can be used in a first step towards the calculation of error bars of any simulated quantity, such as the mixed-layer heat budget. The statistics from an ensemble of 33 simulations are derived in order to infer information on the model errors space and time variability of the main terms of the heat budget. The ensemble is generated by perturbing the wind forcing and the incoming solar radiation as uncertainties on these fields are expected to be a main source of errors for the surface layer representation in the model at monthly to seasonal scales. We focus on the mixed-layer in the Gulf Stream system during the deepening period (Sept.-March). The results indicate that large errors are expected at the Gulf Stream front location and just north of it. The largest errors are found on the zonal and meridional advection and vertical diffusion terms: they can locally reach values that are larger than the terms themselves. We observe a rapid increase with time of the errors for both these terms. The error growth is mainly due to the mesoscale decorrelation. The impact of wind errors on southward Ekman transport and surface turbulence generates uncertainties on the vertical diffusion term just north of the Gulf Stream front. We work with an eddy-permitting configuration similar to those used in ocean reanalysis projects (e.g. SODA, and GLORYS). Our results suggest that for such configurations, at monthly to seasonal time scales, the impact of uncertainties in the atmospheric forcing is weak on the mixed-layer cooling but very large on the zonal and meridional advection and vertical diffusion heat budget terms. In consequence, the estimate of these quantities from ocean reanalyses is not robust with respect to the atmospheric forcing and should be provided with

  3. Multiplafform sampling (ship, aircraft, and satellite) of a Gulf Stream warm core ring.

    PubMed

    Smith, R C; Brown, O B; Hoge, F E; Baker, K S; Evans, R H; Swift, R N; Esaias, W E

    1987-06-01

    The purpose of this paper is to demonstrate the ability to meet the need to measure distributions of physical and biological properties of the ocean over large areas synoptically and over long time periods by means of remote sensing utilizing contemporaneous buoy, ship, aircraft, and satellite (i.e., multiplatform) sampling strategies. A mapping of sea surface temperature and chlorophyll fields in a Gulf Stream warm core ring using the multiplatform approach is described. Sampling capabilities of each sensing system are discussed as background for the data collected by means of these three dissimilar methods. Commensurate space/time sample sets from each sensing system are compared, and their relative accuracies in space and time are determined. The three-dimensional composite maps derived from the data set provide a synoptic perspective unobtainable from single platforms alone.

  4. GEOS-3 ocean current investigation using radar altimeter profiling. [Gulf Stream surface topography

    NASA Technical Reports Server (NTRS)

    Leitao, C. D.; Huang, N. E.; Parra, C. G.

    1978-01-01

    Both quasi-stationary and dynamic departures from the marine geoid were successfully detected using altitude measurements from the GEOS-3 radar altimeter. The quasi-stationary departures are observed either as elevation changes in single pass profiles across the Gulf Stream or at the crowding of contour lines at the western and northern areas of topographic maps generated using altimeter data spanning one month or longer. Dynamic features such as current meandering and spawned eddies can be monitored by comparing monthly mean maps. Comparison of altimeter inferred eddies with IR detected thermal rings indicates agreement of the two techniques. Estimates of current velocity are made using derived slope estimates in conjunction with the geostrophic equation.

  5. Calcareous nannofossil evidence for the existence of the Gulf Stream during the late Maastrichtian

    USGS Publications Warehouse

    Watkins, D.K.; ,

    2005-01-01

    Upper Maastrichtian calcareous nannofossil assemblages, from eight cores on the South Carolina Coastal Plain (onshore set) and three deep sea drilling sites from the continental slope and abyssal hills (offshore set), were analyzed by correlation and principal component analysis to examine the ancient surface water thermal structure. In addition, a temperature index derived from independently published paleobiogeographic information was applied to the sample data. All three methods indicate a strong separation of the samples into onshore and offshore sets, with the offshore data set exhibiting significantly warmer paleotemperatures. The great disparity between these two sample sets indicates that there was a strong thermal contrast between the onshore and offshore surface water masses that persisted throughout the late Maastrichtian despite evident shortterm changes in fertility, productivity, and community structure. This suggests the Gulf Stream was present as a major oceanographic feature during the late Maastrichtian. Copyright 2005 by the American Geophysical Union.

  6. Multiplatform sampling (ship, aircraft, and satellite) of a Gulf Stream warm core ring

    NASA Technical Reports Server (NTRS)

    Smith, Raymond C.; Brown, Otis B.; Hoge, Frank E.; Baker, Karen S.; Evans, Robert H.

    1987-01-01

    The purpose of this paper is to demonstrate the ability to meet the need to measure distributions of physical and biological properties of the ocean over large areas synoptically and over long time periods by means of remote sensing utilizing contemporaneous buoy, ship, aircraft, and satellite (i.e., multiplatform) sampling strategies. A mapping of sea surface temperature and chlorophyll fields in a Gulf Stream warm core ring using the multiplatform approach is described. Sampling capabilities of each sensing system are discussed as background for the data collected by means of these three dissimilar methods. Commensurate space/time sample sets from each sensing system are compared, and their relative accuracies in space and time are determined. The three-dimensional composite maps derived from the data set provide a synoptic perspective unobtainable from single platforms alone.

  7. Dissolved organic matter export in glacial and non-glacial streams along the Gulf of Alaska

    NASA Astrophysics Data System (ADS)

    Hood, E. W.; Scott, D.; Jeffery, A.; Schreiber, S.; Heavner, M.; Edwards, R.; D'Amore, D. V.; Fellman, J.

    2009-12-01

    The Gulf of Alaska drainage basin contains more than 75,000 km2 of glaciers, many of which are rapidly thinning and receding. We are using a paired watershed approach to evaluate how changes in glacier ecosystems will impact the export dissolved organic matter (DOM) into the Gulf of Alaska. Our primary study watersheds, Lemon Creek and Montana Creek, are similar in size, bedrock lithology and elevation range and extend from near sea level to the margin or interior of the Juneau Icefield. Lemon Creek has a glacial coverage of ~60%, while Montana Creek is free of glacier ice. Our goal is to evaluate seasonal differences in the quantity, chemical character and reactivity of DOM being exported from these watersheds to downstream near-shore marine ecosystems. In addition, we are monitoring a variety of physical parameters that influence instream DOM metabolism in both watersheds. Our initial results from the 2009 runoff season indicate that concentrations of dissolved organic carbon (DOC) are substantially higher in the non-glacial watershed. However, fluorescence analyses indicate that DOM from the glacier watershed has a higher protein and lower humic material content compared to DOM from the non-glacial watershed. After the spring snowmelt season, physical parameters between the two watersheds diverged, with higher streamflow and turbidity as well as colder water temperatures in the glacial watershed. Although our previous yield calculations show significantly higher DOC fluxes from the forested watershed, our results here suggest that glacier watersheds may be an important source of labile carbon to the near shore marine ecosystem. The contrast in the physical habitat between the two rivers (e.g glacier stream = cold, low light penetration, unstable substrate) supports the hypothesis that that in-stream DOM processing is limited within glacier dominated rivers, therefore delivering a higher percentage of labile DOM downstream.

  8. Detection and interpretation of ocean roughness variations across the Gulf Stream inferred from radar cross section observations

    NASA Technical Reports Server (NTRS)

    Weissman, D. E.; Thompson, T. W.

    1977-01-01

    Radar cross section data shows that the Gulf Stream has a higher cross section per unit area (interpreted here as a greater roughness) than the water on the continental shelf. A steep gradient in cross section was often seen at the expected location of the western boundary. There were also longer-scale (10-20 km) gradual fluctuations within the stream of significant magnitude. These roughness variations are correlated with the surface shear stress that the local wind imposes on the sea. Using the available surface-truth information concerning the wind speed and direction, an assumed Gulf Stream velocity profile, and high-resolution ocean-surface temperature data obtained by the VHRR onboard a NOAA-NESS polar-orbiting satellite, the present study demonstrates that the computed surface stress variation bears a striking resemblance to the measured radar cross-section variations.

  9. Variation of flow properties during a collision event of two mesoscale eddies in the Gulf Stream region from numerical simulation

    NASA Astrophysics Data System (ADS)

    Chang, Yeon S.; Park, Young-Gyu

    2015-09-01

    The temporal variation of the flow structure and consequent mixing process during the collision of two counter-rotating mesoscale eddies are investigated by analyzing the HYbrid Coordinate Ocean Model simulation for the Gulf Stream region using Eulerian parameters—Okubo-Weiss parameters and horizontal kinetic energy ( KE)—and Lagrangian parameters—finite-size Lyapunov exponent (FSLE) and relative dispersion coefficients ( K r ). During the collision process, a transport barrier constructed by FSLE ridges develops between the two eddies and hyperbolic points are formed at both ends of the barrier. High values of the shear components of strain (> mean + standard deviation) are observed around the hyperbolic points, indicating possible deformation of the eddy. The magnitudes of spatially averaged KE and FSLE values increase (~20% and ~25%, respectively) during the collision as the flows around the main eddy become more energetic and dispersive. The Eulerian measures—the relative vorticity and the shear components of strain—show different temporal evolutions. The former does not significantly vary (~3%) while the latter has a peak value (~34%) at the time of maximum impact of the collision. In contrast, the Lagrangian measures show a similar pattern of temporal variations as both FSLE and K r values generally increase (~25% and ~35%, respectively) during the collision, which indicates increased mixing due to the collision.

  10. Reconstruction of the Gulf Stream since 1900 and correlation with the North Atlantic Oscillation

    NASA Astrophysics Data System (ADS)

    Watelet, Sylvain; Beckers, Jean-Marie; Barth, Alexander

    2015-04-01

    Prevailing winds over the North Atlantic (NA) have a direct influence on the location and intensity of the Gulf Stream (GS) by the transfer of momentum between atmosphere and ocean. Therefore, the study of interannual variability of the GS requires the identification of sources of variability within the atmospheric circulation. Various studies have highlighted the impact of the North Atlantic Oscillation (NAO) on the variability of the GS transport. However, there is still no scientific consensus thereupon. On the one hand, several scientific papers exhibit a decrease of the GS transport during low NAO periods, as well as a higher transport during high NAO phases. On the second hand, other authors suggest a lower transport during positive phases of the NAO. Finally, one study obtained a more complex conclusion, whereby the influence of the NAO is different upstream and downstream of Cape Hatteras. Considering the influence of the NAO on the GS position, studies are more convergent and show a more northern GS during a high NAO phase, while discrepancies remains on the existence and the quantification of the time lag between a specific NAO phase and its consequence on the GS position. This currently limited understanding of the links between the NAO and the GS impels us to further analyze the spatial and temporal distribution of the GS. Our main purpose in this study is to reconstruct a spatially continuous field of ocean (sub)surface circulation in the NA from in situ time series of discrete steps, in order to accurately quantify the position and intensity of the GS since 1900. From there, we are able to examine the correlation of this current with the NAO. To this end, we used the DIVA (Data-Interpolating Variational Analysis) tool, which is a numerical implementation of the variational inverse method (VIM) using the finite elements method to reconstruct continuous fields from discrete measurements. These measurements of temperature and salinity since the beginning

  11. Reconstruction of the Gulf Stream since 1900 and correlation with the North Atlantic Oscillation

    NASA Astrophysics Data System (ADS)

    Watelet, Sylvain; Beckers, Jean-Marie; Barth, Alexander; Ouberdous, Mohamed; Troupin, Charles

    2014-05-01

    Prevailing winds over the North Atlantic (NA) have a direct influence on the location and intensity of the Gulf Stream (GS) by the transfer of momentum between atmosphere and ocean. Therefore, the study of interannual variability of the GS requires the identification of sources of variability within the atmospheric circulation. Various studies have highlighted the impact of the North Atlantic Oscillation (NAO) on the variability of the GS transport. However, there is still no scientific consensus thereupon. On the one hand, several scientific papers (Sato & Rossby, 1995; Curry & McCartney, 2001; deCoëtlogon et al., 2006) exhibit a decrease of the GS transport during low NAO periods, as well as a higher transport during high NAO phases. On the second hand, studies of Gangopadhyay et al. (1992), Baringer & Larsen (2001) and DiNezio et al. (2009) suggest a lower transport during positive phases of the NAO. Finally, Chaudhuri et al. (2011) obtained a more complex conclusion, whereby the influence of the NAO is different upstream and downstream of Cape Hatteras. This currently limited understanding of the links between the NAO and the GS in NA, impels us to further analyze the spatial and temporal distribution of the GS. Our main purpose in this study is to reconstruct a spatially continuous field of ocean (sub)surface circulation in the NA from in situ time series of discrete steps, in order to accurately quantify the position and intensity of the GS since 1900. From there, we will be able to examine the correlation of this current with the NAO. To this end, we used the DIVA (Data-Interpolating Variational Analysis) tool, which is a numerical implementation of the variational inverse method (VIM) using the finite elements method to reconstruct continuous fields from discrete measurements. These measurements of temperature, salinity and currents since the beginning of the last century originate from several data bases, such as WOD (World Ocean Database, NOAA), Sea

  12. Chronology and dynamics of the Amundsen Gulf Ice Stream in Arctic Canada during the last glacial-interglacial transition

    NASA Astrophysics Data System (ADS)

    Lakeman, T. R.; MacLean, B.; Blasco, S.; Bennett, R.; Hughes Clarke, J. E.

    2012-04-01

    An extensive ice stream of the Laurentide ice sheet occupied Amundsen Gulf during the Last Glacial Maximum. The grounded ice stream extended northwestward to the margin of the inner shelf in the Beaufort Sea and to a depth of 450 metres. This glacier was one of the largest ice streams to emanate into the Arctic Ocean during the last glaciation and, as such, exerted a primary influence on the dynamics of the northwest Laurentide Ice Sheet. Ice stream retreat from its maximum position began prior to 13,000 cal yr BP. The pattern of extensive sole marks or glacial flutings on the seabed and on the adjacent mainland and islands confirms the direction of flow was from southeast to northwest. In the Gulf these features are imprinted primarily on subglacial sediment deposits. The bathymetry of the Gulf and known extent of the ice stream on land indicates the ice was at least 700 m thick. A series of moraines at the mouth of the Gulf mark temporary positions of the retreating ice stream margin. Early stages of ice retreat may have been associated with meltwater discharge under the ice stream as evidenced by current erosion associated with some sole marks or glacial flutings. Melting at the leading edge of the ice stream resulted in calving of icebergs and the generation of keel-scour marks in the seabed. Retreat of the ice stream was relatively rapid as indicated by thin and spatially discontinuous deglacial glaciomarine sediment in the Gulf. Furthermore, an expansive database of deglacial radiocarbon ages from eastern Banks Island, western Victoria Island, and the adjacent Arctic mainland, indicates that the ice stream had retreated fully from the Gulf by 12,500 cal yr BP. The lack of Holocene sediment draping the sole marks or flutings, and outcrops of exposed bedrock and glaciomarine sediment indicate very low sedimentation rates since ice retreat. The thin veneer of recent fine sediment that has been deposited discontinuously on the seabed in the Gulf indicates little

  13. Sources and Delivery of Nutrients to the Northwestern Gulf of Mexico from Streams in the South-Central United States

    USGS Publications Warehouse

    Rebich, R.A.; Houston, N.A.; Mize, S.V.; Pearson, D.K.; Ging, P.B.; Evan, Hornig C.

    2011-01-01

    SPAtially Referenced Regressions On Watershed attributes (SPARROW) models were developed to estimate nutrient inputs [total nitrogen (TN) and total phosphorus (TP)] to the northwestern part of the Gulf of Mexico from streams in the South-Central United States (U.S.). This area included drainages of the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf hydrologic regions. The models were standardized to reflect nutrient sources and stream conditions during 2002. Model predictions of nutrient loads (mass per time) and yields (mass per area per time) generally were greatest in streams in the eastern part of the region and along reaches near the Texas and Louisiana shoreline. The Mississippi River and Atchafalaya River watersheds, which drain nearly two-thirds of the conterminous U.S., delivered the largest nutrient loads to the Gulf of Mexico, as expected. However, the three largest delivered TN yields were from the Trinity River/Galveston Bay, Calcasieu River, and Aransas River watersheds, while the three largest delivered TP yields were from the Calcasieu River, Mermentau River, and Trinity River/Galveston Bay watersheds. Model output indicated that the three largest sources of nitrogen from the region were atmospheric deposition (42%), commercial fertilizer (20%), and livestock manure (unconfined, 17%). The three largest sources of phosphorus were commercial fertilizer (28%), urban runoff (23%), and livestock manure (confined and unconfined, 23%). ?? 2011 American Water Resources Association. This article is a U.S. Government work and is in the public domain in the USA.

  14. An approximate Kalman filter for ocean data assimilation: An example with an idealized Gulf Stream model

    NASA Technical Reports Server (NTRS)

    Fukumori, Ichiro; Malanotte-Rizzoli, Paola

    1995-01-01

    A practical method of data assimilation for use with large, nonlinear, ocean general circulation models is explored. A Kalman filter based on approximation of the state error covariance matrix is presented, employing a reduction of the effective model dimension, the error's asymptotic steady state limit, and a time-invariant linearization of the dynamic model for the error integration. The approximations lead to dramatic computational savings in applying estimation theory to large complex systems. We examine the utility of the approximate filter in assimilating different measurement types using a twin experiment of an idealized Gulf Stream. A nonlinear primitive equation model of an unstable east-west jet is studied with a state dimension exceeding 170,000 elements. Assimilation of various pseudomeasurements are examined, including velocity, density, and volume transport at localized arrays and realistic distributions of satellite altimetry and acoustic tomography observations. Results are compared in terms of their effects on the accuracies of the estimation. The approximate filter is shown to outperform an empirical nudging scheme used in a previous study. The examples demonstrate that useful approximate estimation errors can be computed in a practical manner for general circulation models.

  15. AIRSAR observations of the Gulf Stream with interpretation from sea truth and modeling

    NASA Technical Reports Server (NTRS)

    Valenzuela, G. R.; Chubb, S. R.; Marmorino, G. O.; Trump, C. L.; Lee, J. S.; Cooper, A. L.; Askari, F.; Keller, W. C.; Kaiser, J. A. C.; Mied, R. P.

    1991-01-01

    On 20 Jul., JPL/DC-8 synthetic aperture radar (SAR) participated in the 17-21 Jul. 1990 NRL Gulf Stream (GS) experiment in preparation for SIR-C missions in 1993, 1994, and 1996 for calibration purposes and to check modes and techniques for operation at our experimental site off the east coast of the US. During this experiment, coordinated and near simultaneous measurements were performed from ship (R/V Cape Henlopen) and other aircraft (NADC/P-3 and NRL/P-3) to address scientific questions relating to the origin of 'slick-like' features observed by Scully-Power, the refraction and modulation of waves by variable currents, the effect of current and thermal fronts on radar imagery signatures and the modification of Kelvin ship wakes by fronts. The JPL/DC-8 and NADC/P-3 SAR's are fully polarimetric systems. Their composite frequency range varies between P- and X-band. We describe in detail the Airborne SAR (AIRSAR) participation in the Jul. 1990 GS experiment and present preliminary results of the ongoing analysis and interpretation of the radar imagery in the context of ground truth, other remote measurements, and modeling efforts.

  16. Nonlinear Gulf Stream Interaction with the Deep Western Boundary Current System: Observations and a Numerical Simulation

    NASA Technical Reports Server (NTRS)

    Dietrich, David E.; Mehra, Avichal; Haney, Robert L.; Bowman, Malcolm J.; Tseng, Yu-Heng

    2003-01-01

    Gulf Stream (GS) separation near its observed Cape Hatteras (CH) separation location, and its ensuing path and dynamics, is a challenging ocean modeling problem. If a model GS separates much farther north than CH, then northward GS meanders, which pinch off warm core eddies (rings), are not possible or are strongly constrained by the Grand Banks shelfbreak. Cold core rings pinch off the southward GS meanders. The rings are often re-absorbed by the GS. The important warm core rings enhance heat exchange and, especially, affect the northern GS branch after GS bifurcation near the New England Seamount Chain. This northern branch gains heat by contact with the southern branch water upstream of bifurcation, and warms the Arctic Ocean and northern seas, thus playing a major role in ice dynamics, thermohaline circulation and possible global climate warming. These rings transport heat northward between the separated GS and shelf slope/Deep Western Boundary Current system (DWBC). This region has nearly level time mean isopycnals. The eddy heat transport convergence/divergence enhances the shelfbreak and GS front intensities and thus also increases watermass transformation. The fronts are maintained by warm advection by the Florida Current and cool advection by the DWBC. Thus, the GS interaction with the DWBC through the intermediate eddy field is climatologically important.

  17. A model study of the Gulf Stream Extension intrinsic low-frequency variability

    NASA Astrophysics Data System (ADS)

    Quattrocchi, Giovanni; Pierini, Stefano; Dijkstra, Henk A.

    2010-05-01

    A process-oriented model study aimed at understanding aspects of the intrinsic low-frequency variability of the Gulf Stream Extension is presented. Reduced-gravity and two-layer shallow water eddy-permitting models are implemented in a domain spanning the latitudes from 10°S to 60°N, with schematic coastlines representing correctly the large-scale shape of the continental boundaries. The forcing, provided by a time-independent climatological wind stress field, is obtained from 41 years (1961-2001) of ECMWF Re-Analysis data. In the two-layer model a Deep Western Boundary Current is introduced through boundary forcing. The dissipative mechanisms are the lateral eddy viscosity (with coefficient A) and the interfacial friction (with coefficient F) and, in the two-layer model, also the bottom friction. Sensitivity experiments are carried out by varying A and F, and the results are interpreted also in terms of dynamical systems theory. For sufficiently high dissipation a steady western boundary current and corresponding extension jet are obtained: their comparison with AVISO altimeter data provides experimental validation of the model setup. Decreasing A and F leads to a first Hopf bifurcation and to the successive transition to chaotic fluctuations characterized by interannual time scales. A thorough analysis is carried out also by considering previous work on more idealized double-gyre flows.

  18. Characteristics and Seasonality of the Submesoscale Regime in the Gulf Stream Region

    NASA Astrophysics Data System (ADS)

    Mensa, J. A.; Garraffo, Z. D.; Griffa, A.; Ozgokmen, T. M.; Haza, A. C.; Veneziani, C.

    2014-12-01

    Frontogenesis and frontal instabilities in the mixed layer are known to be important processes in the formation of submesoscale features. We study the seasonality of such processes in the Gulf Stream (GS) region. To approach this problem, a realistic simulation with the Hybrid Coordinate Ocean Model (HYCOM) is integrated for 18 months at two horizontal resolutions: a high resolution (1/48th deg) simulation able to resolve part of the submesoscale regime and the full range of mesoscale dynamics, and a coarser resolution (1/12th deg) case, in which submesoscales are not resolved. Results provide an insight into submesoscale dynamics in the complex GS region. A clear seasonal cycle is observed, with submesoscale features mostly present during the winter season in the mixed layer. The submesoscale field is characterized in terms of deviation from geostrophy and 2D dynamics. The limiting and controlling factor in the formation of submesoscales appears to be the depth of the mixed layer, that controls the release of APE stored in the mesoscale fronts present most of the year. Atmospheric forcings are the main energy source behind submesoscale formation, but mostly indirectly through mixed layer deepening. The mixed layer instability scaling proposed by Fox-Kemper et al. 2008 appears to hold, indicating that the parametrization is appropriate even in this complex and mesoscale dominated area.

  19. Atlantic near-term climate variability and the role of a resolved Gulf Stream

    NASA Astrophysics Data System (ADS)

    Siqueira, Leo; Kirtman, Ben P.

    2016-04-01

    There is a continually increasing demand for near-term (i.e., lead times up to a couple of decades) climate information. This demand is partly driven by the need to have robust forecasts and is partly driven by the need to assess how much of the ongoing climate change is due to natural variability and how much is due to anthropogenic increases in greenhouse gases or other external factors. Here we discuss results from a set of state-of-the-art climate model experiments in comparison with observational estimates that show that an assessment of predictability requires models that capture the variability of major oceanic fronts, which are, at best, poorly resolved and may even be absent in the near-term prediction of Intergovernmental Panel on Climate Change class models. This is the first time that air-sea interactions associated with resolved Gulf Stream sea surface temperature have been identified in the context of a state-of-the-art global coupled climate model with inferred near-term predictability.

  20. The meandering Gulf Stream as seen by the Geosat altimeter - Surface transport, position, and velocity variance from 73 deg to 46 deg W

    NASA Technical Reports Server (NTRS)

    Kelly, Kathryn A.

    1991-01-01

    Results are presented of an analysis of the surface geostrophic velocity field for the Gulf Stream region for the position, structure, and surface transport of the Gulf Stream for 2.5 yr of the Geosat altimeter Exact Repeat Mission. Synthetic data using a Gaussian velocity profile were generated and fit to the sea surface residual heights to create a synthetic mean sea surface height field and profiles of absolute geostrophic currents. An analysis of the model parameters and the actual geostrophic velocity profiles revealed two different flow regimes for the Gulf Stream connected by a narrow transition region coincident with the New England Seamount Chain. The upstream region was found to exhibit relatively straight Gulf Stream paths, long Eulerian time scales, and eastward propagating meanders. The downstream region had more large meanders, no consistent propagation direction, and shorter Eulerian time scales. A 25-percent reduction in surface transport occurred in the transition region, with a corresponding reduction in current speed and no change in Gulf Stream width.

  1. A space maintainability experiment aboard the Ben Franklin submersible during the 30-day Gulf Stream drift mission.

    NASA Technical Reports Server (NTRS)

    Kappler, J. R.; May, C. B.

    1972-01-01

    In the summer of 1969, a deep submersible drifted for 30 days below the surface of the Gulf Stream, while operated by a six man crew. The main purpose of the mission was oceanographic research. The crew's activities and completely self-contained environment resembled those of a space station such as Skylab. Because of these similarities aspects of onboard vehicle maintenance during the actual conduct of a scientific mission were investigated. The maintainability study was accomplished in six distinct phases. Two useful plots of manpower distribution were developed. A maintenance action summary is presented in a table.

  2. An Experimental Investigation of Wave Measurements Using a Dual-Beam Interferometer: Gulf Stream as a Surface Wave Guide

    DTIC Science & Technology

    2006-09-13

    from fbr wave analysis. to be further explained in the following . v, and v,. respectively, or from S,& computed from v,. That I is] Of the three...INSAR ANALYSIS OF GULF STREAM WAVE GUIDE C09014 when the change of k following equation (13) is so large wave spectral analysis, a 3 x 3-pixel smoothing...Hwang anUd lie, Y., and W. Alpers (20013), On the nonlinear integral transform of an Shemdin , 19901 and equation (B4) is identically the ocean wave

  3. Monthly Maps of Sea Surface Height in the North Atlantic and Zonal Indices for the Gulf Stream Using TOPEX/Poseidon Altimeter Data

    NASA Technical Reports Server (NTRS)

    Singh, Sandipa; Kelly, Kathryn A.

    1997-01-01

    Monthly Maps of sea surface height are constructed for the North Atlantic Ocean using TOPEX/Poseidon altimeter data. Mean sea surface height is reconstructed using a weighted combination of historical, hydrographic data and a synthetic mean obtained by fitting a Gaussian model of the Gulf Stream jet to altimeter data. The resultant mean shows increased resolution over the hydrographic mean, and incorporates recirculation information that is absent in the synthetic mean. Monthly maps, obtained by adding the mean field to altimeter sea surface height residuals, are used to derive a set of zonal indices that describe the annual cycle of meandering as well as position and strength of the Gulf Stream.

  4. Spatial and temporal patterns in pigment biomass in Gulf Stream warm-core ring 82B and its environs

    NASA Technical Reports Server (NTRS)

    Smith, R. C.; Baker, K. S.

    1985-01-01

    A chronology of the horizontal and vertical distribution of phytoplankton pigment biomass provides a biological life history of Gulf Stream warm-core ring 82B. Development of ring 82B is followed through three distinct periods: a winter/early spring period of deep convective overturn with uniform and relatively high pigment concentrations to depths of 400 m, a late spring stratification period with subsurface (20-30 m) pigment maxima and relatively high ring center values compared to surrounding waters, and a Gulf Stream interaction period when ring characteristics are dominated by intrusions of low pigment concentration waters. While the ring maintains a unique identity throughout these periods of its life, prolonged deep vertical mixing as well as episodic interactions with its surrounding have a significant influence on pigment distributions within the ring. These interactions generally enhance pigment biomass compared to the water mass from which it is derived. A consistent feature of pigment distribution is the remarkable coherence between this measure of phytoplankton biomass and the corresponding physical hydrodynamic structure of the upper water column.

  5. The role of the cold sector of extratropical cyclones in setting atmospheric mean state features of the Gulf Stream basin.

    NASA Astrophysics Data System (ADS)

    Vannière, Benoît; Czaja, Arnaud; Dacre, Helen; Woollings, Tim

    2016-04-01

    The mechanism by which the Gulf Stream SST front anchors a band of precipitation on its warm edge is still a matter of debate and little is known about how synoptic activity contributes to shape precipitation mean state pattern. In this talk, we introduce a new indicator for the cold sector of extratropical storms based on low-level PV. This indicator is used in ERA interim data to separate the cold sector contribution to precipitation and vertical wind from the contribution of the rest of the storm. We find that cold sector precipitation forms a band following the SST front closely. In contrast, the enhanced ascent on the warm edge of the front is set primarily by the warm sector and cannot be directly related to the precipitation band as proposed by previous studies. Numerical sensitivity experiments of an extratropical cyclone passing over different sets of SST further confirms that the anchoring effect of the SST front on precipitation comes exclusively from the cold sector. These results lead us to revisit the atmospheric boundary layer model proposed to describe air-sea interactions over the Gulf-Stream SST gradient. Finally, we explore the role of the cold sector convection in restoring baroclinicity in the wake of an extratropical cyclone.

  6. Trends in nutrient inflows to the Gulf of Mexico from streams draining the conterminous United States, 1972-93

    USGS Publications Warehouse

    Dunn, David E.

    1996-01-01

    Trends are computed for nutrient inflows from 37 streams discharging into the Gulf of Mexico. The drainage areas of these streams represent about 86 percent of the drainage area to the Gulf from the conterminous United States. The period analyzed varies for each stream, but generally includes water years 1972-93. Stations included in this analysis primarily are part of the National Stream Quality Accounting Network operated by the U.S. Geological Survey. Short-term trends for each station are indicated by LOWESS smooth lines superimposed on graphs of the relations between flow-adjusted residuals of concentration and time or load and time. Long-term trends were evaluated using Kendall's tau and the slope of the Kendall-Theil robust line. Long- term trends for each station are indicated by Kendall-Theil robust lines superimposed on the aforementioned graphs. Annual loads are estimated with regression analysis and corrected for log-transformation bias with the Minimum Variance Unbiased Estimator. Trends in annual streamflow are presented to aid in the interpretation of trends in nutrient inflows. Statistically significant, long-term increases in flow-adjusted residual concentrations of total nitrogen were detected at 19 stations, decreases were detected at 7 stations, and no significant trends were detected at 11 stations. Long-term increases in total nitrogen load were detected at 3 stations, decreases were detected at 4 stations, and no significant trends were detected at 30 stations. Long-term increases in flow-adjusted residual concentrations of total phosphorus were detected at 7 stations, decreases were detected at 11 stations, and no significant trends were detected at 19 stations. Long-term increases in total phosphorus load were detected at 3 stations, decreases were detected at 12 stations, and no significant trends were detected at 22 stations. The median yields (mean annual load divided by drainage area) of total nitrogen and total phosphorus were

  7. Comment on: Structure, transport, and vertical coherence of the Gulf Stream from the Straits of Florida to the Southeast Newfoundland Ridge, by Meinen and Luther

    NASA Astrophysics Data System (ADS)

    Savidge, Dana K.

    2016-06-01

    Remarkably low vertical coherences in downstream velocities have been reported recently for three alongstream locations in the Gulf Stream, a Western Boundary Current with known three-dimensional dynamics of a baroclinically and barotropically unstable jet. This comment addresses the possibility that spatial averaging of coherences may be contributing to the low values estimated.

  8. A multi-model analysis of the resolution influence on precipitation climatology in the Gulf Stream region

    NASA Astrophysics Data System (ADS)

    Feng, Xuelei; Huang, Bohua; Kirtman, Ben P.; Kinter, James L.; Chiu, Long S.

    2017-03-01

    Using climate simulations from coupled and uncoupled general circulation models, this study investigates the influence of horizontal resolution in both atmospheric and oceanic model components on the mean precipitation over the Gulf Stream (GS) region. For this purpose, three sets of model experiments are analyzed. The first two examine the effects of increasing horizontal resolution of an atmospheric general circulation model (AGCM) gradually from 100 to 10 km under fixed oceanic settings. Specifically, the AGCM is either forced with prescribed observed sea surface temperature (SST) (the first case) or coupled to a non-eddy-resolving ocean general circulation model (OGCM) at a fixed horizontal resolution near 100 km (the second case). The third set of experiments examines the effects of the oceanic resolution with a pair of long-term simulations by another coupled ocean-atmosphere general circulation model (CGCM), in which the OGCM is run respectively at non-eddy-resolving (100 km) and eddy-resolving (10 km) resolutions, while the AGCM resolution remains fixed at 50 km for both runs. In general, all simulations qualitatively reproduce the gross features of the mean GS precipitation and its annual cycle. At similar AGCM resolutions, the uncoupled models produce a GS rain band that is more realistic in both structure and strength compared to the coupled models with non-eddy-resolving oceans. This is because the prescribed observed SST better represents the gradient near the oceanic front than the non-eddy-resolving OGCMs simulate. An increase from the baseline AGCM resolution produces enhanced climatological GS precipitation, both large-scale and convective, with the latter more tightly confined to the oceanic front. The enhancement, however, is moderate and further increases in resolution achieves diminishing results. On the other hand, an increase in oceanic resolution from non-eddy-resolving to eddy resolving scheme results in more consistent simulations with

  9. Preliminary Research on the Potential Effects of Gulf Stream Energy Turbines on Rates of Productivity and Nutrient Cycling in Pelagic Sargassum Communities

    NASA Astrophysics Data System (ADS)

    Dubbs, L. L.; Piehler, M.

    2014-12-01

    Sargassum is an important and protected genus of pelagic macroalgae that serves as habitat for numerous bacteria, fungi, invertebrates, fish, and sea turtles. Sargassum and its associated communities are also a significant source of carbon, nitrogen, and phosphorus to the otherwise deficient oligotrophic pelagic waters of the Atlantic Ocean. The densest concentration of pelagic Sargassum, primarily comprised of Sargassum natans and S. fluitans, is found in the North Atlantic Central Gyre of the Sargasso Sea, but large quantities are also found in the waters of the continental shelf of the southeastern United States and especially the western edge of the Florida Current/Gulf Stream, including off the coast of North Carolina. This western edge of the Gulf Stream off the North Carolina coast is also of interest for renewable current energy exploration and development because of the constant flow of the Gulf Stream current in close proximity to land at this location, which presents a potential source of substantial baseload power for the east coast of the United States. Marine hydrokinetic turbines placed in the Gulf Stream will likely be placed at depths of 30 to 50 m below the surface of the water, far removed from buoyant Sargassum that floats at the surface of the water and associated fish assemblages that extend to a depth of 3 m. Nonetheless, Gulf Stream turbines may influence the functional roles of Sargassum and its epibionts because the wakes generated by turbines will change turbulence conditions in the water column, which are in turn likely to affect nutrient cycling and productivity. Our research begins to examine how alterations of the Sargassum environment presented by increased turbulence will affect the productivity, nitrogen fixation, and organic matter fluxes of Sargassum macroalgae and their associated epibiotic communities. We have conducted field and laboratory experiments aimed at quantifying the influence of increased turbulence on the

  10. An Experiment to Evaluate Skylab Earth Resources Sensors for Detection of the Gulf Stream. [Straits of Florida

    NASA Technical Reports Server (NTRS)

    Maul, G. A. (Principal Investigator); Gordon, H. R.; Baig, S. R.; Mccaslin, M.; Devivo, R. J.

    1976-01-01

    The author has identified the following significant results. An experiment to evaluate the Skylab earth resources package for observing ocean currents was performed in the Straits of Florida in January 1974. Data from the S190 photographic facility, S191 spectroradiometer and S192 multispectral scanner, were compared with surface observations. The anticyclonic edge of the Gulf Stream could be identified in the Skylab S190A and B photographs, but the cyclonic edge was obscured by clouds. The aircraft photographs were judged not useful for spectral analysis because vignetting caused the blue/green ratios to be dependent on the position in the photograph. The spectral measurement technique could not identify the anticyclonic front, but mass of Florida Bay water which was in the process of flowing into the Straits could be identified and classified. Monte Carlo simulations of the visible spectrum showed that the aerosol concentration could be estimated and a correction technique was devised.

  11. Heat fluxes and roll circulations over the western Gulf Stream during an intense cold-air outbreak

    NASA Technical Reports Server (NTRS)

    Chou, Shu-Hsien; Ferguson, Michael P.

    1991-01-01

    Turbulence and heat fluxes in the marine atmospheric boundary layer (MABL) for three aircraft stacks near the western Gulf Stream front, observed during the Genesis of Atlantic Lows Experiment (GALE) January 28, 1986 cold-air outbreak, has been studied using mixed-layer scaling. The GOES image and stability parameter indicates that these three stacks were in the roll vortex regime. The turbulence structure in the MABL is studied for this case, as well as the significance of roll vortices to heat fluxes. The roll circulations are shown to contribute significantly to the sensible (temperature) and latent heat (moisture) fluxes with importance increasing upward. The results suggest that the entrainment at the MABL top might affect the the budgets of temperature and humidity fluxes in the lower MABL, but not in the unstable surface layer.

  12. Verification of Geosat sea surface topography in the Gulf Stream extension with surface drifting buoys and hydrographic measurements

    NASA Astrophysics Data System (ADS)

    Willebrand, J.; KäSe, R. H.; Stammer, D.; Hinrichsen, H.-H.; Krauss, W.

    1990-03-01

    Altimeter data from Geosat have been analyzed in the Gulf Stream extension area. Horizontal maps of the sea surface height anomaly relative to an annual mean for various 17-day intervals were constructed using an objective mapping procedure. The mean sea level was approximated by the dynamic topography from climatological hydrographic data. Geostrophic surface velocities derived from the composite maps (mean plus anomaly) are significantly correlated with surface drifter velocities observed during an oceanographie experiment in the spring of 1987. The drifter velocities contain much energy on scales less than 100 km which are not resolved in the altimetric maps. It is shown that the composite sea surface height also agrees well with ground verification from hydrographic data along sections in a triangle between the Azores, Newfoundland, and Bermuda, except in regions of high mean gradients.

  13. Present and past Gulf Stream variability in a cold-water coral area off Cape Lookout, West Atlantic

    NASA Astrophysics Data System (ADS)

    Mienis, F.; Pedersen, A.; Duineveld, G.; Seidenkrantz, M.; Fischel, A.; Matos, L.; Bane, J. M.; Frank, N.; Hebbeln, D.; Ross, S.

    2012-12-01

    Cold-water coral mounds are common on the SE slope of the US from Florida to Cape Hatteras between depths of 400-600 m. All coral areas lie in the vicinity of the Gulf Stream, which is characterized by strong currents transporting relatively warm water northwards. Thus far little is known about the recent and past environmental conditions inside the cold-water coral habitats on the SE US slope and particularly the effect of changing patterns of the Gulf Stream. Near Cape Lookout, which is the northern most cold-water coral area on the SE US slope, cold-water corals have formed mounds up to 60 m high with a tear drop shape, which are oriented in a SSW-NNE direction. Past explorations of major reef sites of N Carolina using remote and manned submersibles have shown living Lophelia pertusa colonies on the current facing side of the mound structures and a high biodiversity of associated fauna, especially fish. Two autonomous benthic landers were deployed amidst Lophelia reefs off Cape Lookout (NC) for a period of 6 months to define oceanographic patterns that are relevant for the development and persistence of cold-water coral ecosystems. Furthermore, a 3.6 m long piston core was collected in 2010 during a cruise with the R.V. Pelagia. This pistoncore was used to determine the changes of current strength through time, using foraminiferal counts, stable oxygen and carbon isotopes on foraminifera, XRF and magnetic susceptibility measurements. Cold-water coral fragments were dated with U/Th and foraminifera from the same depth interval were dated with C14. Bottom landers have recorded a number of events that are characterized by of peaks in temperature and salinity, coinciding with increased flow and turbidity. The current during these events was directed to the NNE. During some of these events temperature rose up to 9 degrees in one day. The temporary replacement of the colder bottom water by warm (and saline) water in combination with the strong currents to the NNE

  14. North Atlantic Ocean OSSE system development: Nature Run evaluation and application to hurricane interaction with the Gulf Stream

    NASA Astrophysics Data System (ADS)

    Kourafalou, Vassiliki H.; Androulidakis, Yannis S.; Halliwell, George R.; Kang, HeeSook; Mehari, Michael M.; Le Hénaff, Matthieu; Atlas, Robert; Lumpkin, Rick

    2016-11-01

    A high resolution, free-running model has been developed for the hurricane region of the North Atlantic Ocean. The model is evaluated with a variety of observations to ensure that it adequately represents both the ocean climatology and variability over this region, with a focus on processes relevant to hurricane-ocean interactions. As such, it can be used as the "Nature Run" (NR) model within the framework of Observing System Simulation Experiments (OSSEs), designed specifically to improve the ocean component of coupled ocean-atmosphere hurricane forecast models. The OSSE methodology provides quantitative assessment of the impact of specific observations on the skill of forecast models and enables the comprehensive design of future observational platforms and the optimization of existing ones. Ocean OSSEs require a state-of-the-art, high-resolution free-running model simulation that represents the true ocean (the NR). This study concentrates on the development and data based evaluation of the NR model component, which leads to a reliable model simulation that has a dual purpose: (a) to provide the basis for future hurricane related OSSEs; (b) to explore process oriented studies of hurricane-ocean interactions. A specific example is presented, where the impact of Hurricane Bill (2009) on the eastward extension and transport of the Gulf Stream is analyzed. The hurricane induced cold wake is shown in both NR simulation and observations. Interaction of storm-forced currents with the Gulf Stream produced a temporary large reduction in eastward transport downstream from Cape Hatteras and had a marked influence on frontal displacement in the upper ocean. The kinetic energy due to ageostrophic currents showed a significant increase as the storm passed, and then decreased to pre-storm levels within 8 days after the hurricane advanced further north. This is a unique result of direct hurricane impact on a western boundary current, with possible implications on the ocean

  15. Particulate manganese dynamics in Gulf Stream warm-core rings and surrounding waters of the NW Atlantic

    SciTech Connect

    Bishop, J.K.B.; Fleisher, M.Q. )

    1987-10-01

    Manganese has been measured in size-fractionated particulate matter profiles obtained by large volume in situ filtration of the upper 1000 m of the N.W. Atlantic as part of the Warm Core Rings Experiment (WCRE) in 1982. Environments sampled included Warm Core Rings (WCR) 82B and 82H, the entrainment zone at the edge of these rings, the Slope Water surrounding rings, and the Gulf Stream (GS) and Sargasso Sea (SS) from which the rings formed. Manganese concentrations ranged from 10 pmol kg{sup {minus}1} to 10,000 pmol kg{sup {minus}1} with the extreme values observed in the quasi-isolated core waters of WCR 82B and in a tongue of shelf water at the periphery of WCR 82B, respectively. The majority of the Mn was in the 1-53 {mu}m particle size fraction and most Mn was probably close to 1 {mu}m in size. Mn showed no correlation with major biogenic phases indicating that formation by local biological processes was not an important source. Instead, most particulate Mn present in the waters sampled originated in reducing sediments at the continental margin. Calculations show that WCRs cause offshore particulate Mn transports from the continental margin between 66{degree}W and Cape Hatteras of 8.5 {times} 10{sup 4} to 14 {times} 10{sup 4} mol d{sup {minus}1} with most derived from the continental shelf. Only 4% of the shelf derived Mn becomes entrained in WCRs and the rest is left 8to disperse in the Slope Water or enter the circulation of the Gulf stream. The WCR-induced offshore Mn transports may account for a large fraction of the Mn flux to sediments on the continental slope and upper continental rise.

  16. Effects of flooding and drought on water quality in Gulf Coastal Plain streams in Georgia.

    PubMed

    Golladay, Stephen W; Battle, Juliann

    2002-01-01

    Since 1994, water-quality constituents have been measured monthly in three adjacent Coastal Plain watersheds in southwestern Georgia. During 1994, rainfall was 650 mm above annual average and the highest flows on record were observed. From November 1998 through November 2000, 19 months had below average rainfall. Lowest flows on record were observed during the summer of 2000. The watersheds are human-dominated with row-crop agriculture and managed forestlands being the major land uses. However, one watershed (Chickasawhatchee Creek) had 10 to 13% less agriculture and greater wetland area, especially along the stream. Suspended particles, dissolved organic carbon, NH4-N, and soluble reactive phosphorus concentrations were greater during wet and flood periods compared with dry and drought periods for each stream. Regional hydrologic conditions had little effect on NO3-N or dissolved inorganic carbon. Chickasawhatchee Creek had significantly lower suspended sediment and NO3-N concentrations and greater organic and inorganic carbon concentrations, reflecting greater wetland area and stronger connection to a regional aquifer system. Even though substantial human land use occurred within all watersheds, water quality was generally good and can be attributed to low stream drainage density and relatively intact floodplain forests. Low drainage density minimizes surface run-off into streams. Floodplain forests reduce nonpoint-source pollutants through biological and physical absorption. In addition to preserving water quality, floodplain forests provide important ecological functions through the export of nutrients and organic carbon to streams. Extreme low flows may be disruptive to aquatic life due to both the lack of water and to the scarcity of biologically important materials originating from floodplain forests.

  17. Application of acoustic-Doppler current profiler and expendable bathythermograph measurements to the study of the velocity structure and transport of the Gulf Stream

    NASA Technical Reports Server (NTRS)

    Joyce, T. M.; Dunworth, J. A.; Schubert, D. M.; Stalcup, M. C.; Barbour, R. L.

    1988-01-01

    The degree to which Acoustic-Doppler Current Profiler (ADCP) and expendable bathythermograph (XBT) data can provide quantitative measurements of the velocity structure and transport of the Gulf Stream is addressed. An algorithm is used to generate salinity from temperature and depth using an historical Temperature/Salinity relation for the NW Atlantic. Results have been simulated using CTD data and comparing real and pseudo salinity files. Errors are typically less than 2 dynamic cm for the upper 800 m out of a total signal of 80 cm (across the Gulf Stream). When combined with ADCP data for a near-surface reference velocity, transport errors in isopycnal layers are less than about 1 Sv (10 to the 6th power cu m/s), as is the difference in total transport for the upper 800 m between real and pseudo data. The method is capable of measuring the real variability of the Gulf Stream, and when combined with altimeter data, can provide estimates of the geoid slope with oceanic errors of a few parts in 10 to the 8th power over horizontal scales of 500 km.

  18. Sources and Delivery of Nutrients to the Northwestern Gulf of Mexico from Streams in the South-Central United States1

    PubMed Central

    Rebich, Richard A; Houston, Natalie A; Mize, Scott V; Pearson, Daniel K; Ging, Patricia B; Evan Hornig, C

    2011-01-01

    Abstract SPAtially Referenced Regressions On Watershed attributes (SPARROW) models were developed to estimate nutrient inputs [total nitrogen (TN) and total phosphorus (TP)] to the northwestern part of the Gulf of Mexico from streams in the South-Central United States (U.S.). This area included drainages of the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf hydrologic regions. The models were standardized to reflect nutrient sources and stream conditions during 2002. Model predictions of nutrient loads (mass per time) and yields (mass per area per time) generally were greatest in streams in the eastern part of the region and along reaches near the Texas and Louisiana shoreline. The Mississippi River and Atchafalaya River watersheds, which drain nearly two-thirds of the conterminous U.S., delivered the largest nutrient loads to the Gulf of Mexico, as expected. However, the three largest delivered TN yields were from the Trinity River/Galveston Bay, Calcasieu River, and Aransas River watersheds, while the three largest delivered TP yields were from the Calcasieu River, Mermentau River, and Trinity River/Galveston Bay watersheds. Model output indicated that the three largest sources of nitrogen from the region were atmospheric deposition (42%), commercial fertilizer (20%), and livestock manure (unconfined, 17%). The three largest sources of phosphorus were commercial fertilizer (28%), urban runoff (23%), and livestock manure (confined and unconfined, 23%). PMID:22457582

  19. The effect of the Gulf Stream current field on wave propagation onto South East Florida reefs, studied with SWAN model simulations

    NASA Astrophysics Data System (ADS)

    gravois, U.; Rogers, W. E.; Sheremet, A.; Jensen, T. G.

    2012-12-01

    This study focuses on the prediction of waves and surf on the nearshore reefs of South East Florida. The edge of this reefs tract, outside of Biscayne Bay, Miami, has a steep transition (1:30) from deep to shallow water and also marks the western wall of the Gulf Stream. Geographically the area is bordered by Florida, Cuba and the Bahamas Islands which block the propagation of swell energy and limit the fetch length in all directions except from the North. Related work by the authors on model hindcast validation for this area using HF radar and in situ data exposed the tendency for the wave model SWAN to over predict wave heights on these nearshore reefs for some NE swell events. Based on the findings of the hindcast validation, a series of theoretical SWAN simulations are set up to investigate the sensitivity of nearshore modeled wave heights to the deep water wave direction and also the effect of coupling with the Gulf Stream surface currents. SWAN is run on an outer wave grid centered about the nearshore reefs of interest and forced with a JONSWAP spectrum that is uniform across all of the boundaries for a suite of wave directions and frequencies. The output of the outer grid is used to force a higher resolution inner grid, run with and without Gulf Stream surface current coupling. Bulk wave parameters are output at a nearshore point location on the reef tract for analysis. There are several interesting findings as a result this study. First, there is only a narrow swell window that allows waves to propagate into the nearshore study location. This implies that a relatively small error in deep water swell angle could result in significant differences in the nearshore wave heights and is likely the source of error for the hindcast validation. Secondly, the swell window significantly shifts with the inclusion of the Gulf Stream current field. Gulf Stream refraction has more effect on shorter period wave forcing, so much so, that the optimal swell window is from the

  20. Assimilation of Altimeter Data into a Quasigeostrophic Model of the Gulf Stream System. Part 1; Dynamical Considerations

    NASA Technical Reports Server (NTRS)

    Capotondi, Antonietta; Malanotte-Rizzoli, Paola; Holland, William R.

    1995-01-01

    The dynamical consequences of constraining a numerical model with sea surface height data have been investigated. The model used for this study is a quasigeostrophic model of the Gulf Stream region. The data that have been assimilated are maps of sea surface height obtained as the superposition of sea surface height variability deduced from the Geosat altimeter measurements and a mean field constructed from historical hydrographic data. The method used for assimilating the data is the nudging technique. Nudging has been implemented in such a way as to achieve a high degree of convergence of the surface model fields toward the observations. The assimilation of the surface data is thus equivalent to the prescription of a surface pressure boundary condition. The authors analyzed the mechanisms of the model adjustment and the characteristics of the resultant equilibrium state when the surface data are assimilated. Since the surface data are the superposition of a mean component and an eddy component, in order to understand the relative role of these two components in determining the characteristics of the final equilibrium state, two different experiments have been considered: in the first experiment only the climatological mean field is assimilated, while in the second experiment the total surface streamfunction field (mean plus eddies) has been used. It is shown that the model behavior in the presence of the surface data constraint can be conveniently described in terms of baroclinic Fofonoff modes. The prescribed mean component of the surface data acts as a 'surface topography' in this problem. Its presence determines a distortion of the geostrophic contours in the subsurface layers, thus constraining the mean circulation in those layers. The intensity of the mean flow is determined by the inflow/outflow conditions at the open boundaries, as well as by eddy forcing and dissipation.

  1. Assimilation of Altimeter Data into a Quasigeostrophic Model of the Gulf Stream System. Part 2; Assimilation Results

    NASA Technical Reports Server (NTRS)

    Capotondi, Antonietta; Holland, William R.; Malanotte-Rizzoli, Paola

    1995-01-01

    The improvement in the climatological behavior of a numerical model as a consequence of the assimilation of surface data is investigated. The model used for this study is a quasigeostrophic (QG) model of the Gulf Stream region. The data that have been assimilated are maps of sea surface height that have been obtained as the superposition of sea surface height variability deduced from the Geosat altimeter measurements and a mean field constructed from historical hydrographic data. The method used for assimilating the data is the nudging technique. Nudging has been implemented in such a way as to achieve a high degree of convergence of the surface model fields toward the observations. Comparisons of the assimilation results with available in situ observations show a significant improvement in the degree of realism of the climatological model behavior, with respect to the model in which no data are assimilated. The remaining discrepancies in the model mean circulation seem to be mainly associated with deficiencies in the mean component of the surface data that are assimilated. On the other hand, the possibility of building into the model more realistic eddy characteristics through the assimilation of the surface eddy field proves very successful in driving components of the mean model circulation that are in relatively good agreement with the available observations. Comparisons with current meter time series during a time period partially overlapping the Geosat mission show that the model is able to 'correctly' extrapolate the instantaneous surface eddy signals to depths of approximately 1500 m. The correlation coefficient between current meter and model time series varies from values close to 0.7 in the top 1500 m to values as low as 0.1-0.2 in the deep ocean.

  2. The thermohaline driving mechanism of oceanic jet streams

    NASA Technical Reports Server (NTRS)

    Csanady, G. T.

    1982-01-01

    In a series of publications dealing with the circulation of the North Atlantic, Worthington (1959, 1972, 1976, 1977) has challenged the widely accepted notion that the Gulf Stream system is entirely wind-driven. He was able to demonstrate that the Gulf Stream over its most intense portion south of New England generally intensifies in winter. Worthington postulates that strong surface cooling in winter is the cause of Gulf Stream intensification, i.e., he believes that a thermal mechanism is partially responsible for driving the Gulf Stream. Worthington speaks of 'anticyclogenesis' and of a 'fresh charge of energy' which the Gulf Stream receives at the end of each (severe) winter. A pattern of thermoline circulation arising in the upper layers of the Stream could play a role similar to that of the Hadley circulation in the atmosphere, which derives the subtropical jet stream. The present investigation is concerned with the examination of such a possibility, taking into account the employment of a two-layer model.

  3. Ends Versus Means: A Critical Analysis of the Persian Gulf Crisis (1987- 1988)

    DTIC Science & Technology

    1990-08-01

    comfortable surplus of power in reserve, the nation’s commitments and the nation’s poter ." If the balance between ends and means remains prudent, then the...Dimensions of Political Analysis. Princeton: Princeton University Press, 1974. Summers, Harry G., Jr. On Strategy: A Critical Analysis of the Vietnam War...First Sea Lord." NATO’s 16 Nations. Special Issue, Vol. 34, 1939. Summers, Harry , G., Jr. "Employing Force to Advance Policy." U.S. News & World Report

  4. Distinct protistan assemblages characterize the euphotic zone and deep sea (2500 m) of the western North Atlantic (Sargasso Sea and Gulf Stream).

    PubMed

    Countway, Peter D; Gast, Rebecca J; Dennett, Mark R; Savai, Pratik; Rose, Julie M; Caron, David A

    2007-05-01

    Protistan diversity was characterized at three locations in the western North Atlantic (Sargasso Sea and Gulf Stream) by sequencing 18S rRNA genes in samples from euphotic (< or = 125 m) and bathypelagic depths (2500 m). A total of 923 partial-length protistan sequences were analysed, revealing 324 distinct operational taxonomic units (OTUs) determined by an automated OTU-calling program set to 95% sequence similarity. Most OTUs were comprised of only one or two sequences suggesting a large but rare pool of protistan diversity. Many OTUs from both depth strata were associated with recently described novel alveolate and stramenopile lineages while many OTUs from the bathypelagic were affiliated with Acantharea, Polycystinea and Euglenozoa and were not observed in euphotic zone libraries. Protistan assemblages from the euphotic zone and the deep sea were largely composed of distinct OTUs; only 28 of the 324 protistan OTUs were detected in both shallow and deep sea clone libraries. The diversity of protistan assemblages in the deep sea was distinctly lower than the diversity of euphotic zone assemblages. Protistan assemblages from the Gulf Stream were the most diverse for either depth strata. Overall, protistan assemblages from different stations but comparable depths were more similar than the assemblages from different depths at the same station. These data suggest that particular groups of protistan OTUs formed distinct 'shallow' and 'deep-sea' assemblages across widely spaced oceanic locales.

  5. Glacially-megalineated limestone terrain of Anticosti Island, Gulf of St. Lawrence, Canada; onset zone of the Laurentian Channel Ice Stream

    NASA Astrophysics Data System (ADS)

    Eyles, Nick; Putkinen, Niko

    2014-03-01

    Anticosti is a large elongate island (240 km long, 60 km wide) in eastern Canada within the northern part of a deep water trough (Gulf of St. Lawrence) that terminates at the Atlantic continental shelf edge. The island's Pleistocene glaciological significance is that its long axis lay transverse to ice from the Quebec and Labrador sectors of the Laurentide Ice Sheet moving south from the relatively high-standing Canadian Shield. Recent glaciological reconstructions place a fast-flowing ice stream along the axis of the Gulf of St. Lawrence but supporting geologic evidence in terms of recognizing its hard-bedded onset zone and downstream streamlined soft bed is limited. Anticosti Island consists of gently southward-dipping limestone plains composed of Ordovician and Silurian limestones (Vaureal, Becscie and Jupiter formations) with north-facing escarpments transverse to regional ice flow. Glacial deposits are largely absent and limestone plains in the higher central plateau of the island retain a relict apparently ‘preglacial’ drainage system consisting of deeply-incised dendritic bedrock valleys. In contrast, the bedrock geomorphology of the lower lying western and eastern limestone plains of the island is strikingly different having been extensively modified by glacial erosion. Escarpments are glacially megalineated with a distinct ‘zig-zag’ planform reflecting northward-projecting bullet-shaped ‘noses’ (identified as rock drumlins) up to 2 km wide at their base and 4 km in length with rare megagrooved upper surfaces. Drumlins are separated by southward-closing, funnel-shaped ‘through valleys’ where former dendritic valleys have been extensively altered by the streaming of basal ice through gaps in the escarpments. Glacially-megalineated bedrock terrain such as on the western and eastern flanks of Anticosti Island is elsewhere associated with the hard-bedded onset zones of fast flowing ice streams and provides important ground truth for the

  6. Evaluation of a new side-stream, low dead space, end-tidal carbon dioxide monitoring system in rats.

    PubMed

    Beck, Christopher; Barthel, Franziska; Hahn, Anna-Maria; Vollmer, Christian; Bauer, Inge; Picker, Olaf

    2014-01-01

    The aim of this study was to evaluate a newly developed infrared side-stream capnograph with minimal sample volume for the continuous measurement of end-tidal carbon dioxide (CO2) concentrations in small rodents. Thirty-four male Wistar rats (weight 345 ± 70 g) were treated in accordance with the National Institutes of Health (NIH) guidelines for animal care. All experiments were performed with approval of the local animal care and use committee. Sepsis was induced by implanting an 18 gauge stent into the colon 24 h prior to the experiments, allowing a constant fecal leakage into the peritoneal cavity (25 septic and nine control animals). Hemodynamic variables and end-tidal CO2 were recorded continuously and arterial blood (5 × 120 µL) was sampled periodically for arterial blood gas analysis. After baseline controlled mechanical ventilation was randomized and titrated to either normocapnia (35-45 mmHg) or hypercapnia (65-75 mmHg) with exogenous application of CO2. A total of 155 paired CO2 measurements comparing end-tidal and arterial partial pressure were conducted. Side-stream capnography underestimated the CO2 partial pressure with a bias of -6.1 mmHg and a 95% limit of agreement from 6.7 to -19.1 mmHg. Our results suggest that side-stream end-tidal CO2 monitoring with a low dead space could be utilized in rats as a surrogate for the arterial CO2 measurement over a wide range of partial pressures in normal and septic animals.

  7. Tracking the evolution of stream DOM source during storm events using end member mixing analysis based on DOM quality

    NASA Astrophysics Data System (ADS)

    Yang, Liyang; Chang, Soon-Woong; Shin, Hyun-Sang; Hur, Jin

    2015-04-01

    The source of river dissolved organic matter (DOM) during storm events has not been well constrained, which is critical in determining the quality and reactivity of DOM. This study assessed temporal changes in the contributions of four end members (weeds, leaf litter, soil, and groundwater), which exist in a small forested watershed (the Ehwa Brook, South Korea), to the stream DOM during two storm events, using end member mixing analysis (EMMA) based on spectroscopic properties of DOM. The instantaneous export fluxes of dissolved organic carbon (DOC), chromophoric DOM (CDOM), and fluorescent components were all enhanced during peak flows. The DOC concentration increased with the flow rate, while CDOM and humic-like fluorescent components were diluted around the peak flows. Leaf litter was dominant for the DOM source in event 2 with a higher rainfall, although there were temporal variations in the contributions of the four end members to the stream DOM for both events. The contribution of leaf litter peaked while that of deeper soils decreased to minima at peak flows. Our results demonstrated that EMMA based on DOM properties could be used to trace the DOM source, which is of fundamental importance for understanding the factors responsible for river DOM dynamics during storm events.

  8. Reply to "Comment on: Structure, transport, and vertical coherence of the Gulf Stream from the Straits of Florida to the Southeast Newfoundland Ridge, by Meinen and Luther" by Dana K. Savidge

    NASA Astrophysics Data System (ADS)

    Meinen, Christopher S.; Luther, Douglas S.

    2016-06-01

    Savidge (2016) raises a concern about how the spatial averaging embodied in our Gulf Stream analysis of vertical coherence (Meinen and Luther, 2016) might contribute to the low coherence found. This response addresses the concerns raised in the Savidge (2016) short comment.

  9. Reply to "Comment on: Structure, transport, and vertical coherence of the Gulf Stream from the Straits of Florida to the Southeast Newfoundland Ridge, by Meinen and Luther" by Dana K. Savidge

    NASA Astrophysics Data System (ADS)

    Meinen, Christopher S.; Luther, Douglas S.

    2016-05-01

    Savidge (2016) raises a concern about how the spatial averaging embodied in our Gulf Stream analysis of vertical coherence (Meinen and Luther, 2016) might contribute to the low coherence found. This response addresses the concerns raised in the Savidge (2016) short comment.

  10. Impact of the Atlantic meridional overturning circulation on the decadal variability of the Gulf Stream path and regional chlorophyll and nutrient concentrations

    NASA Astrophysics Data System (ADS)

    Sanchez-Franks, A.; Zhang, R.

    2015-11-01

    In this study, we show that the underlying physical driver for the decadal variability in the Gulf Stream (GS) path and the regional biogeochemical cycling is linked to the low frequency variability in the Atlantic meridional overturning circulation (AMOC). There is a significant anticorrelation between AMOC variations and the meridional shifts of the GS path at decadal time scale in both observations and two Earth system models (ESMs). The chlorophyll and nutrient concentrations in the GS region are found significantly correlated with the AMOC fingerprint and anticorrelated with the GS path at decadal time scale through coherent isopycnal changes in the GS front in the ESMs. Our results illustrate how changes in the large-scale ocean circulation, such as AMOC, are teleconnected with regional decadal physical and biogeochemical variations near the North American east coast. Such linkages are useful for predicting future physical and biogeochemical variations in this region.

  11. Phytoplankton bloom in Persian Gulf

    NASA Technical Reports Server (NTRS)

    2002-01-01

    There is a large amount of sediment clearly visible in the true-color image of the Persian Gulf, acquired on November 1, 2001, by MODIS. Carried by the confluence of the Tigris and Euphrates Rivers (at center), the sediment-laden waters appear light brown where they enter the northern end of the Persian Gulf and then gradually dissipate into turquoise swirls as they drift southward. The nutrients these sediments carry are helping to support a phytoplankton bloom in the region, which adds some darker green hues in the rich kaleidoscope of colors on the surface (see the high resolution image). The confluence of the Tigris and Euphrates Rivers marks the southernmost boundary between Iran (upper right) and Iraq (upper left). South of Iraq are the countries of Kuwait and Saudi Arabia. The red dots indicate the probable locations of fires burning at oil refineries. Thin black plumes of smoke can be seen streaming away from several of these.

  12. Accelerated flooding along the U.S. East Coast: On the impact of sea-level rise, tides, storms, the Gulf Stream, and the North Atlantic Oscillations

    NASA Astrophysics Data System (ADS)

    Ezer, Tal; Atkinson, Larry P.

    2014-08-01

    Recent studies identified the U.S. East Coast north of Cape Hatteras as a "hotspot" for accelerated sea-level rise (SLR), and the analysis presented here shows that the area is also a "hotspot for accelerated flooding." The duration of minor tidal flooding [defined as 0.3 m above MHHW (mean higher high water)] has accelerated in recent years for most coastal locations from the Gulf of Maine to Florida. The average increase in annual minor flooding duration was ˜20 h from the period before 1970 to 1971-1990, and ˜50 h from 1971-1990 to 1991-2013; spatial variations in acceleration of flooding resemble the spatial variations of acceleration in sea level. The increase in minor flooding can be predicted from SLR and tidal range, but the frequency of extreme storm surge flooding events (0.9 m above MHHW) is less predictable, and affected by the North Atlantic Oscillations (NAO). The number of extreme storm surge events since 1960 oscillates with a period of ˜15 year and interannual variations in the number of storms are anticorrelated with the NAO index. With higher seas, there are also more flooding events that are unrelated to storm surges. For example, it is demonstrated that week-long flooding events in Norfolk, VA, are often related to periods of decrease in the Florida Current transport. The results indicate that previously reported connections between decadal variations in the Gulf Stream (GS) and coastal sea level may also apply to short-term variations, so flood predictions may be improved if the GS influence is considered.

  13. Can the Gulf Stream induce coherent short-term fluctuations in sea level along the US East Coast? A modeling study

    NASA Astrophysics Data System (ADS)

    Ezer, Tal

    2016-02-01

    Much attention has been given in recent years to observations and models that show that variations in the transport of the Atlantic Meridional Overturning Circulation (AMOC) and in the Gulf Stream (GS) can contribute to interannual, decadal, and multi-decadal variations in coastal sea level (CSL) along the US East Coast. However, less is known about the impact of short-term (time scales of days to weeks) fluctuations in the GS and their impact on CSL anomalies. Some observations suggest that these anomalies can cause unpredictable minor tidal flooding in low-lying areas when the GS suddenly weakens. Can these short-term CSL variations be attributed to changes in the transport of the GS? An idealized numerical model of the GS has been set up to test this proposition. The regional model uses a 1/12° grid with a simplified coastline to eliminate impacts from estuaries and small-scale coastal features and thus isolate the GS impact. The GS in the model is driven by inflows/outflows, representing the Florida Current (FC), the Slope Current (SC), and the Sargasso Sea (SS) flows. Forcing the model with an oscillatory FC transport with a period of 2, 5, and 10 days produced coherent CSL variations from Florida to the Gulf of Maine with similar periods. However, when imposing variations in the transports of the SC or the SS, they induce CSL variations only north of Cape Hatteras. The suggested mechanism is that variations in GS transport produce variations in sea level gradient across the entire GS length and this large-scale signal is then transmitted into the shelf by the generation of coastal-trapped waves (CTW). In this idealized model, the CSL variations induced by variations of ˜10 Sv in the transport of the GS are found to resemble CSL variations induced by ˜5 m s-1 zonal wind fluctuations, though the mechanisms of wind-driven and GS-driven sea level are quite different. Better understanding of the relation between variations in offshore currents and CSL will help

  14. A numerical analysis of shipboard and coastal zone color scanner time series of new production within Gulf Stream cyclonic eddies in the South Atlantic Bight

    NASA Technical Reports Server (NTRS)

    Pribble, J. Raymond; Walsh, John J.; Dieterle, Dwight A.; Mueller-Karger, Frank E.

    1994-01-01

    Eddy-induced upwelling occurs along the western edge of the Gulf Stream between Cape Canaveral, Florida, and Cape Hatteras, North Carolina, in the South Atlantic Bight (SAB). Coastal zone color scanner images of 1-km resolution spanning the period April 13-21, 1979, were processed to examine these eddy features in relation to concurrent shipboard and current/temperature measurements at moored arrays. A quasi-one-dimensional (z), time dependent biological model, using only nitrate as a nutrient source, has been combined with a three-dimensional physical model in an attempt to replicate the observed phytoplankton field at the northward edge of an eddy. The model is applicable only to the SAB south of the Charleston Bump, at approximately 31.5 deg N, since no feature analogous to the bump exists in the model bathymetry. The modeled chlorophyll, nitrate, and primary production fields of the euphotic zone are very similar to those obtained from the satellite and shipboard data at the leading edges of the observed eddies south of the Charleston Bump. The horizontal and vertical simulated fluxes of nitrate and chlorophyll show that only approximately 10% of the upwelled nitrate is utilized by the phytoplankton of the modeled grid box on the northern edge of the cyclone, while approximately 75% is lost horizontally, with the remainder still in the euphotic zone after the 10-day period of the model. Loss of chlorophyll due to sinking is very small in this strong upwelling region of the cyclone. The model is relatively insensitive to variations in the sinking parameterization and the external nitrate and chlorophyll fields but is very sensitive to a reduction of the maximum potential growth rate to half that measured. Given the success of this model in simulating the new production of the selcted upwelling region, other upwelling regions for which measurements or successful models of physical and biological quantities and rates exist could be modeled similarly.

  15. Ice stream behaviour in the western sector of the North Sea during the end of the last glacial cycle

    NASA Astrophysics Data System (ADS)

    Roberts, David; Evans, David; Clark, Chris; Bateman, Mark; Livingstone, Stephen; Medialdea, Alicia; Cofaigh, Colm O.; Grimoldi, Elena; Callard, Louise; Dove, Dayton; Stewart, Heather; Davies, Bethan; Chiverell, Richard

    2016-04-01

    During the last glacial cycle the East coast of the UK was overrun by the British-Irish Ice Sheet (BIIS) flowing eastwards and southwards. In recent years it has become evident that several ice streams including the Tweed, Tyne, and Stainmore Gap ice streams, as well as the late stage North Sea Lobe (NSL), all played a role in shaping the glacial landscape during this period, but understanding the flow phasing of these ice streams during advance and collapse has proved challenging. Here we present new data from the seafloor collected during recent work undertaken by the Britice Chrono and Glanam project teams during cruise JC123 in the North Sea. Sub-bottom seafloor data together with new swath data clearly show that the final phases of the collapse of the NSL were controlled by ice sourced from the Firth of Forth ice stream which deglaciated in a NNW trajectory. Other ice streams being fed from the west (e.g. Stainmore, Tyne, Tweed) were not influential in final phase ice retreat from the southern North Sea. The Forth ice imprint is characterised by several grounding zone/till wedges marking dynamic, oscillatory retreat of the ice as it retreated along an offshore corridor between North Yorkshire and Northumberland. Repeated packages of tills, ice marginal and glaciomarine sediments, which drape glacially scoured bedrock terrain and drumlins along this corridor, point to marine inundation accompanying ice retreat. New TCN ages suggest decoupling of the Tyne Gap ice stream and NSL between 17.8 and 16.5 ka and this coincides with rapid, regional collapse of the NSL between 17.2 and 16.0 ka along the Yorkshire and Durham coasts (new OSL ages; Britice Chrono). Hence, both the central and northern sectors of the BIIS were being strongly influenced by marine margin instability during the latter phases of the last glacial cycle.

  16. Revisiting the problem of the Gulf Stream separation: on the representation of topography in ocean models with different types of vertical grids

    NASA Astrophysics Data System (ADS)

    Ezer, Tal

    2016-08-01

    The difficulty of simulating a realistic Gulf Stream (GS) that separates from the coast at Cape Hatteras has troubled numerical ocean modelers for a long time, and the problem is evident in different models, from the early models of the 1980s to the modern models of today. The source of the problem is not completely understood yet, since GS simulations are sensitive to many different factors, such as numerical parameterization, model grid, treatment of topography and forcing fields. A curious result of early models is that models with terrain-following vertical grids (e.g., "sigma" or "s" coordinates) seem to achieve a better GS separation than z-level models of similar resolution, so the impact of the vertical grid type on GS simulations is revisited here. An idealized generalized coordinate numerical model is used to compare between a sigma-coordinate grid and a z-level grid while maintaining the same numerical code and model parameters. Short-term diagnostic-prognostic calculations focus on the initial dynamic adjustment of the GS from a given initial condition and imposed boundary conditions. In diagnostic calculations, wherein the three-dimensional flow field is adjusted to time-invariant temperature and salinity data, the GS is quite realistic independent of the grid type. However, when switching to prognostic calculations, the GS in the z-level model tends to immediately develop an unrealistic GS branch that continues along the continental slope instead of separating from the coast at Cape Hatteras. The GS is more realistic in either a sigma-coordinate model or in a z-level model with a vertical wall replacing the continental slope. Increasing the vertical resolution in the z-level model reduces numerical noise, but it does not solve the GS separation problem. Vorticity balance analysis shows that the Joint Effect of Baroclinicity and bottom Relief (JEBAR) and its associated bottom pressure torque are very sensitive to the choice of vertical grid. A stepped

  17. Thermal Regime at the Base of the West-Antarctic Ice Stream Tributaries - is the Holocene Decay of the West Antarctic Ice Sheet Coming to an End?

    NASA Astrophysics Data System (ADS)

    Vogel, S. W.; Tulaczyk, S.; Joughin, I.

    2001-12-01

    and the temperature at the bed was below the pressure melting point or 3b) that basal resistance in the tributaries is with 1 to 10 kPa similar small to the basal resistance in the ice streams. Our calculations indicate that the presence of the basal ice layer at UpC has important implications for the models of WAIS stability. In both cases, 3a and 3b, the results are sensitive to small perturbations in the basal energy balance, which can lead to either increased lubrication, favoring a possible collapse of the WAIS or to increased basal resistance in favor of a possible stabilization of the WAIS. Although our model does not give a straight answer on whether the Holocene decay of the WAIS is coming to an end or not, it indicates that significant basal freezing has been and/or is currently occurring, basal freeze-on may increase basal resistance and eventually contributing to a stabilization of the WAIS. We therefore formulate the testable hypothesis that over large areas in the ice stream tributaries the basal energy balance is negative and freezing occurs increasing basal resistance. Further research and the acquisition of field data is necessary to decrease uncertainties in the basal energy balance, to test the hypothesis and so to increase the chance to successfully predict the future behavior of the WAIS.

  18. Proceedings of the Workshop on Gulf Stream Structure and Variability Held at Research Triangle Park, North Carolina on 1-2 April 1982.

    DTIC Science & Technology

    1982-04-01

    and William Gerard de Brahm. Irmago I4undi, 28(2), 105-120, 1976. Herrera y Tordesillas, Antonio de, Historia general de los hechos de los Castellanos...and minima , and the shaded area covers one standard deviation in each band. The mean variance estimates have about 20 degrees of freedom in each band. i...1982). .4 112 700 W w2Dt OuIOR tS’IO~*J AA APERIOD (DAYS) L PERIOD (DAYS) w 20 402 0.- 5 . 4 PERIOD (DAYS)1 B 60r GULF of MEXICO 90 I-I W1 rr 2 20 47 35

  19. Phylogeography of Pteronotropis signipinnis, P. euryzonus, and the P. hypselopterus Complex (Teleostei: Cypriniformes), with Comments on Diversity and History of the Gulf and Atlantic Coastal Streams

    PubMed Central

    Mayden, Richard L.; Allen, Jason

    2015-01-01

    The cyprinid genus Pteronotropis is endemic to southeastern Gulf of Mexico and Atlantic Ocean of North America. Never before has the genus been demonstrated to be monophyletic. We investigate both the phylogenetic relationships and the phylogeography of some species in the genus using mitochondrial ND2 sequences. In no analysis is the genus resolved as monophyletic if Notropis harperi is not included in the genus. Biogeographic and phylogeographic evaluations are conducted with Pteronotropis, including P. signipinnis, P. euryzonus, and the P. hypselopterus complex. Patterns of relationships and population genetic analyses support divergences within multiple clades both at the species level and within species that are tied to abiotic changes in the region. Replicated patterns across clades are observed, as well as patterns previously found in other taxa. Pteronotropis hypselopterus is likely not a natural grouping as populations from some drainages form clades more closely related to other species of the genus. The general patterns of relationships indicate likely cryptic species not currently recognized. Finally, the patterns of species relationships and clades and population structuring within species serve as another example of replicated divergences in the biodiversity east and west of the Mobile Bay. PMID:26114110

  20. 75 FR 64171 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Reef Fish Fishery of the Gulf of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-19

    ... reached by October 28, 2010. This closure is necessary to prevent overfishing of Gulf greater amberjack... legal requirements to prevent and end overfishing and rebuild greater amberjack in the Gulf. On August 4... prevent overfishing of Gulf greater amberjack and increase the likelihood that the 2010 quota will not...

  1. Detecting changes in the transport of the Gulf Stream and the Atlantic overturning circulation from coastal sea level data: The extreme decline in 2009-2010 and estimated variations for 1935-2012

    NASA Astrophysics Data System (ADS)

    Ezer, Tal

    2015-06-01

    Recent studies reported weakening in the Atlantic Meridional Overturning Circulation (AMOC) and in the Gulf Stream (GS), using records of about a decade (RAPID project) or two (altimeter data). Coastal sea level records are much longer, so the possibility of detecting climatic changes in ocean circulation from sea level data is intriguing and thus been examined here. First, it is shown that variations in the AMOC transport from the RAPID project since 2004 are consistent with the flow between Bermuda and the U. S. coast derived from the Oleander measurements and from sea level difference (SLDIF). Despite apparent disagreement between recent studies on the ability of data to detect weakening in the GS flow, estimated transport changes from 3 different independent data sources agree quite well with each other on the extreme decline in transport in 2009-2010. Due to eddies and meandering, the flow representing the GS part of the Oleander line is not correlated with AMOC or with the Florida Current, only the flow across the entire Oleander line from the U.S. coast to Bermuda is correlated with climatic transport changes. Second, Empirical Mode Decomposition (EMD) analysis shows that SLDIF can detect (with lag) the portion of the variations in the AMOC transport that are associated with the Florida Current and the wind-driven Ekman transport (SLDIF-transport correlations of ~ 0.7-0.9). The SLDIF has thus been used to estimate variations in transport since 1935 and compared with AMOC obtained from reanalysis data. The significant weakening in AMOC after ~ 2000 (~ 4.5 Sv per decade) is comparable to weakening seen in the 1960s to early 1970s. Both periods of weakening AMOC, in the 1960s and 2000s, are characterized by faster than normal sea level rise along the northeastern U.S. coast, so monitoring changes in AMOC has practical implications for coastal protection.

  2. Paleosols in low-order streams and valley heads in the Araucaria Plateau - Record of continental environmental conditions in southern Brazil at the end of MIS 3

    NASA Astrophysics Data System (ADS)

    Paisani, Julio Cesar; Pontelli, Marga Eliz; Osterrieth, Margarita Luisa; Paisani, Sani Daniela Lopes; Fachin, Andressa; Guerra, Simone; Oliveira, Leandro

    2014-10-01

    The Araucaria Plateau is a geomorphological unit that occupies approximately three-quarters of the terrain in the southern region of Brazil. The plateau displays different altitudinal levels (600 to <1400 m a.s.l.) that are locally recognized as remnants of planed surfaces (S8-S1). These surfaces are maintained by basic (S3-S8) and acidic (S1 and S2) volcanic flows from the Neocretaceous period of the Paraná Basin. The largest extent of this plateau is located in a humid subtropical climate zone. Colluvial, colluvial-alluvial, alluvial sediments and paleosols (Ab diagnostic horizons) occur predominantly in S2. The paleosols are located in low-hierarchical-order fossil valleys (first- to fourth-order in Strahler's stream classification) and valley heads, which are referred to as paleovalleys in this paper. We employed these paleosols as stratigraphic level markers of the pedogenesis of the regional Upper Quaternary and propose their importance as records of the paleoenvironmental conditions of the Araucaria Plateau in areas above 1200 m a.s.l. These paleosols were dated by 14C and show ages between 23.8 ± 0.05 kyr BP (28.06-29.08 kyr cal. BP) and 41.16 ± 0.48 kyr BP (44.13-45.58 kyr cal. BP). The calibrated ages are related to Marine Isotope Stage 3 (MIS 3), in which the last period of global warming occurred (approximately 60-25 kyr cal. BP). We integrated the morphological, pedogeochemical, clay fraction mineralogy, micromorphological and δC-13 analyses of five paleosols from S2 to verify the paleoenvironmental conditions of the Araucaria Plateau and its correspondence with the paleoclimatic phenomena that were identified on a global scale during MIS 3 in the Southern Hemisphere. We obtained the following conclusions: a) the properties of paleosols reflect pedological processes that are adjusted to the paleoenvironmental conditions at the end of MIS 3 and the transition to MIS 2 (Last Glacial Maximum); b) aplasmogenic partial acidolysis was the predominant

  3. The Puzzling Ophiuchus Stream

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-01-01

    Dwarf galaxies or globular clusters orbiting the Milky Way can be pulled apart by tidal forces, leaving behind a trail of stars known as a stellar stream. One such trail, the Ophiuchus stream, has posed a serious dynamical puzzle since its discovery. But a recent study has identified four stars that might help resolve this streams mystery.Conflicting TimescalesThe stellar stream Ophiuchus was discovered around our galaxy in 2014. Based on its length, which appears to be 1.6 kpc, we can calculate the time that has passed since its progenitor was disrupted and the stream was created: ~250 Myr. But the stars within it are ~12 Gyr old, and the stream orbits the galaxy with a period of ~350 Myr.Given these numbers, we can assume that Ophiuchuss progenitor completed many orbits of the Milky Way in its lifetime. So why would it only have been disrupted 250 million years ago?Fanning StreamLed by Branimir Sesar (Max Planck Institute for Astronomy), a team of scientists has proposed an idea that might help solve this puzzle. If the Ophiuchus stellar stream is on a chaotic orbit common in triaxial potentials, which the Milky Ways may be then the stream ends can fan out, with stars spreading in position and velocity.The fanned part of the stream, however, would be difficult to detect because of its low surface brightness. As a result, the Ophiuchus stellar stream could actually be longer than originally measured, implying that it was disrupted longer ago than was believed.Search for Fan StarsTo test this idea, Sesar and collaborators performed a search around the ends of the stream, looking for stars thatare of the right type to match the stream,are at the predicted distance of the stream,are located near the stream ends, andhave velocities that match the stream and dont match the background halo stars.Histogram of the heliocentric velocities of the 43 target stars. Six stars have velocities matching the stream velocity. Two of these are located in the main stream; the other

  4. Florida Gulf Stream Data (FLDA) Current Study

    DTIC Science & Technology

    1994-03-01

    Inc., January 1993 c C c VAX varies left dimension the fastest DIMENSION datau(36 1,66), datav (36 1,66),spd(7, 13) integer*2 idir(7,13) character*3...8217) write(*,*)’ Beginning ’,files(month) read( 1, 1000)datau 1000 formnat(22f6.1) close(unit-- 1,status=’keep’) C c open v input file, read data into datav ...close v input file open(unit=l1,file=files(month)/f..yinterp.dat’,status=-’old’) read(1 , 000) datav close(unit= 1 ,status=’keep’) C c open output file

  5. Gulf Stream Protection Act of 2011

    THOMAS, 112th Congress

    Sen. Nelson, Bill [D-FL

    2011-02-17

    02/17/2011 Read twice and referred to the Committee on Energy and Natural Resources. (text of measure as introduced: CR S907-908) (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

  6. 76 FR 64248 - Gulf of Mexico Reef Fish Fishery; Closure of the 2011 Gulf of Mexico Commercial Sector for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-18

    ... economic zone (EEZ) of the Gulf of Mexico (Gulf). These actions are necessary to reduce overfishing of the... to end overfishing and prevent overfishing from occurring. AMs are management controls to prevent...)(15) of the Magnuson-Stevens Act mandates the establishment of ACLs at a level such that...

  7. Gulf of Tonkin.

    ERIC Educational Resources Information Center

    Martel, Erich

    1992-01-01

    Presents a lesson on the Gulf of Tonkin incident during the Vietnam War and the resulting Tonkin Gulf Resolution. Recommends using the resolution as a way of studying the war making powers of the U.S. presidency. Includes excerpts from the Tonkin Gulf Resolution as student readings. (CFR)

  8. A HYCOM modeling study of the Persian Gulf: 2. Formation and export of Persian Gulf Water

    NASA Astrophysics Data System (ADS)

    Yao, Fengchao; Johns, William E.

    2010-11-01

    The circulation and water mass transformation processes in the Persian Gulf and the water exchange with the Indian Ocean through the Strait of Hormuz are studied using the Hybrid Coordinate Ocean Model (HYCOM). Model results suggest that intruding Indian Ocean Surface Water (IOSW) is transformed into hypersaline waters with salinity >41 practical salinity unit by the fresh water loss in the northern end of the gulf and in the southern shallow banks. During wintertime, intense heat loss from sea to air leads to the formation of cold and saline waters both in the northern gulf and in the southern gulf. Dense waters formed in the southern gulf have higher salinity and spill into the axial deep trough of the gulf as a sporadic bottom outflow in winter, which leads to high-salinity pulses in the strait as observed, whereas in summer their buoyancy is increased due to heating and they are exported as a warm yet salty intermediate depth flow through the strait. Dense waters formed in the northern gulf propagate toward the strait along the axial trough throughout the year. Correspondingly, there are two branches of seasonal overturning circulation in density classes: the northern branch peaking in August with strength of 0.13 Sv and the southern branch peaking in February and December with strength of 0.08 Sv. These two branches outflow together feed a seasonally varying deep outflow through the strait with an annual mean volume transport of 0.12 Sv.

  9. CodedStream: live media streaming with overlay coded multicast

    NASA Astrophysics Data System (ADS)

    Guo, Jiang; Zhu, Ying; Li, Baochun

    2003-12-01

    Multicasting is a natural paradigm for streaming live multimedia to multiple end receivers. Since IP multicast is not widely deployed, many application-layer multicast protocols have been proposed. However, all of these schemes focus on the construction of multicast trees, where a relatively small number of links carry the multicast streaming load, while the capacity of most of the other links in the overlay network remain unused. In this paper, we propose CodedStream, a high-bandwidth live media distribution system based on end-system overlay multicast. In CodedStream, we construct a k-redundant multicast graph (a directed acyclic graph) as the multicast topology, on which network coding is applied to work around bottlenecks. Simulation results have shown that the combination of k-redundant multicast graph and network coding may indeed bring significant benefits with respect to improving the quality of live media at the end receivers.

  10. Discontinuous ephemeral streams

    NASA Astrophysics Data System (ADS)

    Bull, William B.

    1997-07-01

    Many ephemeral streams in western North America flowed over smooth valley floors before transformation from shallow discontinuous channels into deep arroyos. These inherently unstable streams of semiarid regions are sensitive to short-term climatic changes, and to human impacts, because hillslopes supply abundant sediment to infrequent large streamflow events. Discontinuous ephemeral streams appear to be constantly changing as they alternate between two primary modes of operation; either aggradation or degradation may become dominant. Attainment of equilibrium conditions is brief. Disequilibrium is promoted by channel entrenchment that causes the fall of local base level, and by deposition of channel fans that causes the rise of local base level. These opposing base-level processes in adjacent reaches are maintained by self-enhancing feedback mechanisms. The threshold between erosion and deposition is crossed when aggradational or degradational reaches shift upstream or downstream. Extension of entrenched reaches into channel fans tends to create continuous arroyos. Upvalley migration of fan apexes tends to create depositional valley floors with few stream channels. Less than 100 years is required for arroyo cutting, but more than 500 years is required for complete aggradation of entrenched stream channels and valley floors. Discontinuous ephemeral streams have a repetitive sequence of streamflow characteristics that is as distinctive as sequences of meander bends or braided gravel bars in perennial rivers. The sequence changes from degradation to aggradation — headcuts concentrate sheetflow, a single trunk channel conveys flow to the apex of a channel fan, braided distributary channels end in an area of diverging sheetflow, and converging sheetflow drains to headcuts. The sequence is repeated at intervals ranging from 15 m for small streams to more than 10 km for large streams. Lithologic controls on the response of discontinuous ephemeral streams include: (1

  11. CENTRIFUGE END CAP

    DOEpatents

    Beams, J.W.; Snoddy, L.B.

    1960-08-01

    An end cap for ultra-gas centrifuges is designed to impart or remove angular momentum to or from the gas and to bring the entering gas to the temperature of the gas inside the centrifuge. The end cap is provided with slots or fins for adjusting the temperature and the angular momentum of the entering gas to the temperature and momentum of the gas in the centrifuge and is constructed to introduce both the inner and the peripheral stream into the centrifuge.

  12. GulfSnow Peach

    Technology Transfer Automated Retrieval System (TEKTRAN)

    GulfSnow peach is jointly released for grower trial by the U.S. Department of Agriculture, Agricultural Research Service (Byron, GA), Georgia Agricultural Experiment Station and Florida Agricultural Experiment Station. GulfSnow was previously tested as AP06-09W and originated from a cross of AP98-3...

  13. Gulf of Mexico

    Atmospheric Science Data Center

    2014-05-15

    ... article title:  Continued Spread of Gulf of Mexico Oil Slick       View Larger ... on NASA's Terra spacecraft passed over the Deepwater Horizon oil slick in the Gulf of Mexico on May 8, 2010, at approximately 16:50 UTC ...

  14. Rings dominate western Gulf

    NASA Astrophysics Data System (ADS)

    Vidal L., Francisco V.; Vidal L., Victor M. V.; Molero, José María Pérez

    Surface and deep circulation of the central and western Gulf of Mexico is controlled by interactions of rings of water pinched from the gulf's Loop Current. The discovery was made by Mexican oceanographers who are preparing a full-color, 8-volume oceanographic atlas of the gulf.Anticyclonic warm-core rings pinch off the Loop Current at a rate of about one to two per year, the scientists of the Grupo de Estudios Oceanográficos of the Instituto de Investigaciones Eléctricas (GEO-IIE) found. The rings migrate west until they collide with the continental shelf break of the western gulf, almost always between 22° and 23°N latitude. On their westward travel they transfer angular momentum and vorticity to the surrounding water, generating cyclonic circulations and vortex pairs that completely dominate the entire surface and deep circulation of the central and western gulf.

  15. stream-stream: Stellar and dark-matter streams interactions

    NASA Astrophysics Data System (ADS)

    Bovy, Jo

    2017-02-01

    Stream-stream analyzes the interaction between a stellar stream and a disrupting dark-matter halo. It requires galpy (ascl:1411.008), NEMO (ascl:1010.051), and the usual common scientific Python packages.

  16. Stream Studies.

    ERIC Educational Resources Information Center

    Hamilton City Board of Education (Ontario).

    This manual provides teachers with some knowledge of ecological study methods and techniques used in collecting data when plants and animals are studied in the field. Most activities deal with the interrelatedness of plant and animal life to the structure and characteristics of a stream and pond. Also included in this unit plan designed for the…

  17. Exxon's Hondo Field goes on stream - at last

    SciTech Connect

    Wilson, H.M.

    1981-05-04

    After more than 10 years of frustrating regulatory delays and an outlay of $600 million, Exxon Co. USA has brought on stream its rich Hondo Oil Field in the Santa Ynez Unit of California's Santa Barbara Channel. The first wells on Hondo Platform A are delivering crude into a storage and treating vessel anchored nearby. The first carrier tanker arrived in mid-April 1981, to take on the first cargo of produced oil. The crude will travel in 5 dedicated shuttle tankers through the Panama Canal to Exxon's Baytown, Texas Refinery. Seventeen wells have been drilled so far from the 945 ft tall platform, installed in 850 ft of water near the western end of the channel. That water depth ranks second in US offshore development to a platform in the Gulf of Mexico. By the end of this year Hondo Field will be producing 30,000 bpd. In 1982, when 24 wells are producing and 4 injection wells are returning water and natural gas to the reservoir, production will rise to its peak of 35,000 to 40,000 bpd.

  18. Gulf of Mexico Initiative: NASA Capacity Building in the Gulf Region

    NASA Astrophysics Data System (ADS)

    Armstrong, D.; Graham, W. D.; Searby, N. D.

    2012-12-01

    In the wake of hurricanes Katrina and Rita, NASA created the Gulf of Mexico Initiative (GOMI) to help the region recover and to build the capacity of local and regional organizations to utilize NASA Earth science assets to establish effective policies, encourage sustainable natural resource management and utilization, and to expeditiously respond to crises. GOMI worked closely with the Gulf of Mexico Alliance (GOMA), a regional collaboration of the five US Gulf states and 13 federal agencies, to select projects that addressed high priority issues of the region. Many capabilities developed by this initiative have been adopted by end-users and have been leveraged to respond to other natural and man made disasters such as the Deepwater Horizon oil spill (2010), record breaking floods along the Mississippi River (2011), unprecedented tornado supercells (2011), and extreme drought (2012). Examples of successful capacity building projects will be presented and the lessons learned from these projects will be discussed.

  19. NASA Gulf of Mexico Initiative Hypoxia Research

    NASA Technical Reports Server (NTRS)

    Armstrong, Curtis D.

    2012-01-01

    The Applied Science & Technology Project Office at Stennis Space Center (SSC) manages NASA's Gulf of Mexico Initiative (GOMI). Addressing short-term crises and long-term issues, GOMI participants seek to understand the environment using remote sensing, in-situ observations, laboratory analyses, field observations and computational models. New capabilities are transferred to end-users to help them make informed decisions. Some GOMI activities of interest to the hypoxia research community are highlighted.

  20. Gulf of Mexico

    Atmospheric Science Data Center

    2014-05-15

    article title:  Unique Views of Gulf Oil Slick     View Larger Image ... where the oil appears bright. The result causes the oil spill to stand out dramatically in shades of cyan, while other features like ...

  1. UAVSAR_Gulf_Oil

    NASA Video Gallery

    NASA's Gulfstream III research aircraft carrying the Jet Propulsion Laboratory’s sophisticated UAVSAR synthetic aperture radar under its belly surveyed the spread of the Gulf of Mexico oil spill du...

  2. Gulf Sturgeon Facts

    USGS Publications Warehouse

    Sulak, Kenneth J.; Randall, Michael

    2008-01-01

    Sturgeon: An ancient type of fish, with 5 rows of armor scutes, a cartilaginous skeleton, long snout, suction mouth, no teeth, and 4 barbels. Photograph of a Gulf sturgeon. The total length of a 5-month old is 313 mm.

  3. Methods of separating particulate residue streams

    DOEpatents

    Hoskinson, Reed L.; Kenney, Kevin L.; Wright, Christopher T.; Hess, J. Richard

    2011-04-05

    A particulate residue separator and a method for separating a particulate residue stream may include an air plenum borne by a harvesting device, and have a first, intake end and a second, exhaust end; first and second particulate residue air streams that are formed by the harvesting device and that travel, at least in part, along the air plenum and in a direction of the second, exhaust end; and a baffle assembly that is located in partially occluding relation relative to the air plenum and that substantially separates the first and second particulate residue air streams.

  4. Gulf of Mexico Regional Collaborative Final Report

    SciTech Connect

    Judd, Kathleen S.; Judd, Chaeli; Engel-Cox, Jill A.; Gulbransen, Thomas; Anderson, Michael G.; Woodruff, Dana L.; Thom, Ronald M.; Guzy, Michael; Hardin, Danny; Estes, Maury

    2007-12-01

    This report presents the results of the Gulf of Mexico Regional Collaborative (GoMRC), a year-long project funded by NASA. The GoMRC project was organized around end user outreach activities, a science applications team, and a team for information technology (IT) development. Key outcomes are summarized below for each of these areas. End User Outreach; Successfully engaged federal and state end users in project planning and feedback; With end user input, defined needs and system functional requirements; Conducted demonstration to End User Advisory Committee on July 9, 2007 and presented at Gulf of Mexico Alliance (GOMA) meeting of Habitat Identification committee; Conducted significant engagement of other end user groups, such as the National Estuary Programs (NEP), in the Fall of 2007; Established partnership with SERVIR and Harmful Algal Blooms Observing System (HABSOS) programs and initiated plan to extend HABs monitoring and prediction capabilities to the southern Gulf; Established a science and technology working group with Mexican institutions centered in the State of Veracruz. Key team members include the Federal Commission for the Protection Against Sanitary Risks (COFEPRIS), the Ecological Institute (INECOL) a unit of the National Council for science and technology (CONACYT), the Veracruz Aquarium (NOAA’s first international Coastal Ecology Learning Center) and the State of Veracruz. The Mexican Navy (critical to coastal studies in the Southern Gulf) and other national and regional entities have also been engaged; and Training on use of SERVIR portal planned for Fall 2007 in Veracruz, Mexico Science Applications; Worked with regional scientists to produce conceptual models of submerged aquatic vegetation (SAV) ecosystems; Built a logical framework and tool for ontological modeling of SAV and HABs; Created online guidance for SAV restoration planning; Created model runs which link potential future land use trends, runoff and SAV viability; Analyzed SAV

  5. Toxicological assessments of Gulf War veterans

    PubMed Central

    Brown, Mark

    2006-01-01

    Concerns about unexplained illnesses among veterans of the 1991 Gulf War appeared soon after that conflict ended. Many environmental causes have been suggested, including possible exposure to depleted uranium munitions, vaccines and other drugs used to protect troops, deliberate or accidental exposure to chemical warfare agents and pesticides and smoke from oil-well fires. To help resolve these issues, US and UK governments have sought independent expert scientific advice from prestigious, independent scientific and public health experts, including the US National Academies of Science and the UK Royal Society and Medical Research Council. Their authoritative and independent scientific and medical reviews shed light on a wide range of Gulf War environmental hazards. However, they have added little to our understanding of Gulf War veterans' illnesses, because identified health effects have been previously well characterized, primarily in the occupational health literature. This effort has not identified any new health effects or unique syndromes associated with the evaluated environmental hazards. Nor do their findings provide an explanation for significant amounts of illnesses among veterans of the 1991 Gulf War. Nevertheless, these independent and highly credible scientific reviews have proven to be an effective means for evaluating potential health effects from deployment-related environmental hazards. PMID:16687269

  6. Nitrogen input to the Gulf of Mexico

    USGS Publications Warehouse

    Goolsby, D.A.; Battaglin, W.A.; Aulenbach, Brent T.; Hooper, R.P.

    2001-01-01

    Historical streamflow and concentration data were used in regression models to estimate the annual flux of nitrogen (N) to the Gulf of Mexico and to determine where the nitrogen originates within the Mississippi Basin. Results show that for 1980-1996 the mean annual total N flux to the Gulf of Mexico was 1 568 000 t yr-1. The flux was about 61% nitrate N, 37% organic N, and 2% ammonium N. The flux of nitrate N to the Gulf has approximately tripled in the last 30 years with most of the increase occurring between 1970 and 1983. The mean annual N flux has changed little since the early 1980s, but large year-to-year variations in N flux occur because of variations in precipitation. During wet years the N flux can increase by 50% or more due to flushing of nitrate N that has accumulated in the soils and unsaturated zones in the basin. The principal source areas of N are basins in southern Minnesota, Iowa, Illinois, Indiana, and Ohio that drain agricultural land. Basins in this region yield 1500 to more than 3100 kg N km-2 yr-1 to streams, several times the N yield of basins outside this region.

  7. Nitrogen input to the Gulf of Mexico.

    PubMed

    Goolsby, D A; Battaglin, W A; Aulenbach, B T; Hooper, R P

    2001-01-01

    Historical streamflow and concentration data were used in regression models to estimate the annual flux of nitrogen (N) to the Gulf of Mexico and to determine where the nitrogen originates within the Mississippi Basin. Results show that for 1980-1996 the mean annual total N flux to the Gulf of Mexico was 1,568,000 t yr-1. The flux was about 61% nitrate N, 37% organic N, and 2% ammonium N. The flux of nitrate N to the Gulf has approximately tripled in the last 30 years with most of the increase occurring between 1970 and 1983. The mean annual N flux has changed little since the early 1980s, but large year-to-year variations in N flux occur because of variations in precipitation. During wet years the N flux can increase by 50% or more due to flushing of nitrate N that has accumulated in the soils and unsaturated zones in the basin. The principal source areas of N are basins in southern Minnesota, Iowa, Illinois, Indiana, and Ohio that drain agricultural land. Basins in this region yield 1500 to more than 3100 kg N km-2 yr-1 to streams, several times the N yield of basins outside this region.

  8. Obesity in gulf countries.

    PubMed

    ALNohair, Sultan

    2014-01-01

    Globally obesity has reached to epidemic proportions, and the people of the Gulf countries have also affected, especially high-income, oil-producing countries. The prevalence of obesity in Gulf Countries among children and adolescents ranges from 5% to 14% in males and from 3% to 18% in females. In adult females there is a significant increase of obesity with a prevalence of 2%-55% and in adult males 1%-30% in countries of gulf region. Over the last two decades there is increased consumption of fast foods and sugar-dense beverages (e.g., sodas). Simultaneously, technological advances - cars, elevators, escalators, and remotes have lead to a decrease in level of activity. Traditional dependence on locally grown natural products such as dates, vegetables, wheat and has also shifted. Changes in food consumption, socioeconomic and demographic factors, physical activity, and urbanization are being important factors that contribute to the increased prevalence of obesity in the region.

  9. Obesity in Gulf Countries

    PubMed Central

    ALNohair, Sultan

    2014-01-01

    Globally obesity has reached to epidemic proportions, and the people of the Gulf countries have also affected, especially high-income, oil-producing countries. The prevalence of obesity in Gulf Countries among children and adolescents ranges from 5% to 14% in males and from 3% to 18% in females. In adult females there is a significant increase of obesity with a prevalence of 2%–55% and in adult males 1%–30% in countries of gulf region. Over the last two decades there is increased consumption of fast foods and sugar-dense beverages (e.g., sodas). Simultaneously, technological advances – cars, elevators, escalators, and remotes have lead to a decrease in level of activity. Traditional dependence on locally grown natural products such as dates, vegetables, wheat and has also shifted. Changes in food consumption, socioeconomic and demographic factors, physical activity, and urbanization are being important factors that contribute to the increased prevalence of obesity in the region. PMID:24899882

  10. Gulf of Suez, Egypt

    SciTech Connect

    Schuetz, K.I. )

    1988-08-01

    The Gulf of Suez is an intracratonic rift basin which originated in the early Miocene on the once-continuous Arabo-African plate. The Precambrian crystalline basement is overlain by a platform cover of Early Cambrian to Eocene age. There is no evidence of tectonic precursors to the Miocene breakup. Marine transgressions, for example during the Carboniferous and Cretaceous, followed wide embayments caused by long-wavelength oscillations trending northwest-southeast on the North African craton. This article discusses the geologic history of the Gulf.

  11. Water Masses and Nutrient Sources to the Gulf of Maine.

    PubMed

    Townsend, David W; Pettigrew, Neal R; Thomas, Maura A; Neary, Mark G; McGillicuddy, Dennis J; O'Donnell, James

    2015-01-01

    discuss evidence of modified Gulf Stream ring water that penetrated to Jordan Basin in summer of 2013.

  12. Gulf Coast Wetlands

    Atmospheric Science Data Center

    2014-05-15

    article title:  Wetlands of the Gulf Coast     ... web of estuarine channels and extensive coastal wetlands that provide important habitat for fisheries. The city of New Orleans ... or below sea level. The city is protected by levees, but the wetlands which also function as a buffer from storm surges have been ...

  13. "Going Mobile" in Business Communication at an Arabian Gulf University

    ERIC Educational Resources Information Center

    Rapanta, Chrysi; Nickerson, Catherine; Goby, Valerie Priscilla

    2014-01-01

    In this article, we describe a project in which undergraduate business seniors at a university in the Arabian Gulf created or evaluated the chapters of an iBook as part of their final course in business communication. Students were surveyed throughout the project, and they also participated in a focus group discussion at the end. The aim was to…

  14. Streaming Media Seminar--Effective Development and Distribution of Streaming Multimedia in Education

    ERIC Educational Resources Information Center

    Mainhart, Robert; Gerraughty, James; Anderson, Kristine M.

    2004-01-01

    Concisely defined, "streaming media" is moving video and/or audio transmitted over the Internet for immediate viewing/listening by an end user. However, at Saint Francis University's Center of Excellence for Remote and Medically Under-Served Areas (CERMUSA), streaming media is approached from a broader perspective. The working definition includes…

  15. 78 FR 14225 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Gulf of Mexico Reef Fish Fishery...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-05

    .... This action is necessary to reduce overfishing of the gray triggerfish resource in the Gulf of Mexico... Magnuson-Stevens Act implemented new requirements that ACLs and AMs be established to end overfishing and prevent overfishing from occurring. Accountability measures are management controls to prevent ACLs...

  16. 75 FR 35335 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Gulf of Mexico Reef Fish Fishery...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-22

    ... greater amberjack sector of the Gulf reef fish fishery. These actions are necessary to reduce overfishing... new requirements that annual catch limits (ACLs) and AMs be established to end overfishing and prevent overfishing from occurring. AMs are management controls to prevent ACLs from being exceeded, and correct...

  17. Gulf Stream Temperature, Salinity and Transport During the Last Millennium

    DTIC Science & Technology

    2006-02-01

    their relationship to 9 one another and to proxies of solar variability. Chapter 3 addresses the temperature and salinity components of the...Florida Current 618Oc varied coherently with proxies of atmospheric radiocarbon at low frequencies over 10 the last 5,000 years, suggesting a link...cooling that began around 1000 A.D. models and proxies used. This two-stage character of the LIA is not apparent in the Florida margin cores. 6.4

  18. The dynamics of oceanic fronts. Part 1: The Gulf Stream

    NASA Technical Reports Server (NTRS)

    Kao, T. W.

    1970-01-01

    The establishment and maintenance of the mean hydrographic properties of large scale density fronts in the upper ocean is considered. The dynamics is studied by posing an initial value problem starting with a near surface discharge of buoyant water with a prescribed density deficit into an ambient stationary fluid of uniform density. The full time dependent diffusion and Navier-Stokes equations for a constant Coriolis parameter are used in this study. Scaling analysis reveals three independent length scales of the problem, namely a radius of deformation or inertial length scale, Lo, a buoyance length scale, ho, and a diffusive length scale, hv. Two basic dimensionless parameters are then formed from these length scales, the thermal (or more precisely, the densimetric) Rossby number, Ro = Lo/ho and the Ekman number, E = hv/ho. The governing equations are then suitably scaled and the resulting normalized equations are shown to depend on E alone for problems of oceanic interest. Under this scaling, the solutions are similar for all Ro. It is also shown that 1/Ro is a measure of the frontal slope. The governing equations are solved numerically and the scaling analysis is confirmed. The solution indicates that an equilibrium state is established. The front can then be rendered stationary by a barotropic current from a larger scale along-front pressure gradient. In that quasisteady state, and for small values of E, the main thermocline and the inclined isopycnics forming the front have evolved, together with the along-front jet. Conservation of potential vorticity is also obtained in the light water pool. The surface jet exhibits anticyclonic shear in the light water pool and cyclonic shear across the front.

  19. Interferometric synthetic aperture radar imagery of the Gulf Stream

    NASA Technical Reports Server (NTRS)

    Ainsworth, T. L.; Cannella, M. E.; Jansen, R. W.; Chubb, S. R.; Carande, R. E.; Foley, E. W.; Goldstein, R. M.; Valenzuela, G. R.

    1993-01-01

    The advent of interferometric synthetic aperture radar (INSAR) imagery brought to the ocean remote sensing field techniques used in radio astronomy. Whilst details of the interferometry differ between the two fields, the basic idea is the same: Use the phase information arising from positional differences of the radar receivers and/or transmitters to probe remote structures. The interferometric image is formed from two complex synthetic aperture radar (SAR) images. These two images are of the same area but separated in time. Typically the time between these images is very short -- approximately 50 msec for the L-band AIRSAR (Airborne SAR). During this short period the radar scatterers on the ocean surface do not have time to significantly decorrelate. Hence the two SAR images will have the same amplitude, since both obtain the radar backscatter from essentially the same object. Although the ocean surface structure does not significantly decorrelate in 50 msec, surface features do have time to move. It is precisely the translation of scattering features across the ocean surface which gives rise to phase differences between the two SAR images. This phase difference is directly proportional to the range velocity of surface scatterers. The constant of proportionality is dependent upon the interferometric mode of operation.

  20. Deep Crustal Structure Northern Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Christeson, G. L.; Van Avendonk, H. J.; Eddy, D. R.; Norton, I. O.; Karner, G. D.; Johnson, C. A.; Kneller, E. A.; Snedden, J.

    2013-12-01

    The Gulf of Mexico is a small ocean basin between the US and Mexico that opened up soon after the breakup of Pangea. Although the area has been heavily surveyed with seismic reflection profiles, the deep structure of the region is poorly understood because of lack of penetration beneath the thick sediments and salt. We present the results of the GUMBO (GUlf of Mexico Basin Opening) project that constrains seismic velocities and thicknesses of the sediments and crust from the continental shelf to deep ocean basin in the northern Gulf of Mexico. Data were acquired in 2010 along four profiles 300-500 km in length, using the industry vessel R/V Iron Cat and ocean bottom seismometers at 10-12 km spacing. Plate tectonic models for the Gulf of Mexico region have rifting initiating in the Late Triassic or Early Jurassic, with seafloor spreading beginning ~166-154 Ma in the western Gulf, propagating to the eastern Gulf, and ending ~154-135 Ma. Many models include transform motion along the Florida margin during initiation of continental rifting. We observe a strong change in rifting style from west to east across the ocean basin. Our western profile, offshore Texas, images highly heterogeneous crust with sediment velocities directly overlying Moho in some locations. These observations are consistent with either sedimentary basins within rifted continental crust or ultra-slow-spreading oceanic crust. The profile offshore Lousiana images thicker, faster, and more homogeneous crust. This could suggest an eastward increase in magmatic output during rifting. The eastern profiles offshore Alabama and Florida image the ocean-continent boundary and extensive regions of oceanic crust. The thickness of crystalline crust from the continental shelf to the deep basin decreases from ~25 km to 6-7 km over a horizontal distance of 150 km in the eastern Gulf of Mexico. The profile offshore Alabama, near a region where syn-rift volcanism has been interpreted on seismic reflection data, has

  1. 33 CFR 110.194b - Mississippi Sound and Gulf of Mexico, near Petit Bois Island, Miss.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Mississippi Sound and Gulf of... Mississippi Sound and Gulf of Mexico, near Petit Bois Island, Miss. (a) The anchorage grounds—(1) Explosives...′09″, longitude 88°29′13″, in the waters of Mississippi Sound north of the west end of Petit...

  2. 33 CFR 110.194b - Mississippi Sound and Gulf of Mexico, near Petit Bois Island, Miss.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Mississippi Sound and Gulf of... Mississippi Sound and Gulf of Mexico, near Petit Bois Island, Miss. (a) The anchorage grounds—(1) Explosives...′09″, longitude 88°29′13″, in the waters of Mississippi Sound north of the west end of Petit...

  3. 33 CFR 110.194b - Mississippi Sound and Gulf of Mexico, near Petit Bois Island, Miss.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Mississippi Sound and Gulf of... Mississippi Sound and Gulf of Mexico, near Petit Bois Island, Miss. (a) The anchorage grounds—(1) Explosives...′09″, longitude 88°29′13″, in the waters of Mississippi Sound north of the west end of Petit...

  4. 33 CFR 110.194b - Mississippi Sound and Gulf of Mexico, near Petit Bois Island, Miss.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Mississippi Sound and Gulf of... Mississippi Sound and Gulf of Mexico, near Petit Bois Island, Miss. (a) The anchorage grounds—(1) Explosives...′09″, longitude 88°29′13″, in the waters of Mississippi Sound north of the west end of Petit...

  5. Variability of the Anticyclonic Circulation in the Western Gulf of Mexico.

    DTIC Science & Technology

    1981-09-01

    geopotentlal north of the gyre, and a low in the Bay of Campeche . Behrlnger et. al. (1977) analyze average monthly temper- atures at 200 m and find a large area...sometimes observed in the Bay of Campeche . The high feature at about 250N, 91oW is most likely the Loop Current. NOAA - NESS - EPB weekly Gulf Stream

  6. Experimental investigation of acoustic streaming in a cylindrical wave guide up to high streaming Reynolds numbers.

    PubMed

    Reyt, Ida; Bailliet, Hélène; Valière, Jean-Christophe

    2014-01-01

    Measurements of streaming velocity are performed by means of Laser Doppler Velocimetry and Particle Image Velociimetry in an experimental apparatus consisting of a cylindrical waveguide having one loudspeaker at each end for high intensity sound levels. The case of high nonlinear Reynolds number ReNL is particularly investigated. The variation of axial streaming velocity with respect to the axial and to the transverse coordinates are compared to available Rayleigh streaming theory. As expected, the measured streaming velocity agrees well with the Rayleigh streaming theory for small ReNL but deviates significantly from such predictions for high ReNL. When the nonlinear Reynolds number is increased, the outer centerline axial streaming velocity gets distorted towards the acoustic velocity nodes until counter-rotating additional vortices are generated near the acoustic velocity antinodes. This kind of behavior is followed by outer streaming cells only and measurements in the near wall region show that inner streaming vortices are less affected by this substantial evolution of fast streaming pattern. Measurements of the transient evolution of streaming velocity provide an additional insight into the evolution of fast streaming.

  7. Exploring Linkages Between Gulf of Mexico Sea Surface Conditions and North American Hydroclimate during the Holocene

    NASA Astrophysics Data System (ADS)

    Richey, J. N.; Thirumalai, K.; Quinn, T. M.; Poore, R. Z.

    2015-12-01

    The Gulf of Mexico is part of the Atlantic Warm Pool, a feature that drives oceanic moisture flux to the surrounding continent. It is connected to the North Atlantic Ocean via the loop current, which transports salt and heat from the Caribbean and Gulf of Mexico poleward via the Gulf Stream. As such, variations in Gulf of Mexico sea surface temperature (SST) and salinity (SSS) are linked to changes in North Atlantic Ocean circulation and North American hydroclimate. Although SST and SSS variability in the Gulf of Mexico are well understood on inter-annual and glacial-interglacial timescales, little is known about centennial scale variability in these sea surface parameters through the Holocene. We present here the first continuous multi-decadal resolution time series of SST and SSS spanning the entire Holocene from the Gulf of Mexico. This proxy reconstruction is based on paired measurements of Mg/Ca and δ18O in the planktic foraminifer, Globigerinoides ruber (white variety) in the Garrison Basin. Using these data, in combination with additional Gulf of Mexico SST and SSS records from the late Holocene, we explore linkages between North American precipitation patterns and ocean circulation on centennial timescales.

  8. Gulf of California, Mexico

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Sunglint on the water's surface reveals the complex pattern of currents in the Gulf of California in the vicinity of Tiburon and Angel de la Guarda Islands (29.0N, 113.0W). Mexico's state of Sonora and the Sonora Desert is on the mainland and the state of Baja California consists of the entire peninsula. The Pacific Ocean is under the coastal cloud cover on the Baja peninsula.

  9. Traveltime and longitudinal dispersion in Illinois streams

    USGS Publications Warehouse

    Graf, Julia B.

    1986-01-01

    Twenty-seven measurements of traveltime and longitudinal dispersion in 10 Illinois streams made from 1975 to 1982 provide data needed for estimating traveltime of peak concentration of a conservative solute, traveltime of the leading edge of a solute cloud, peak concentration resulting from injection of a given quantity of solute, and passage time of solute past a given point on a stream. These four variables can be estimated graphically for each stream from distance of travel and either discharge at the downstream end of the reach or flow-duration frequency. From equations developed from field measurements, the traveltime and dispersion characteristics also can be estimated for other unregulated streams in Illinois that have drainage areas less than about 1,500 square miles. For unmeasured streams, traveltime of peak concentration and of the leading edge of the cloud are related to discharge at the downstream end of the reach and to distance of travel. For both measured and unmeasured streams, peak concentration and passage time are best estimated from the relation of each to traveltime. In measured streams, dispersion efficiency is greater than that predicted by Fickian diffusion theory. The rate of decrease in peak concentration with traveltime is about equal to the rate of increase in passage time. Average velocity in a stream reach, given by the velocity of the center of solute mass in that reach, can be estimated from an equation developed from measured values. The equation relates average reach velocity to discharge at the downstream end of the reach. Average reach velocities computed for 9 of the 10 streams from available equations that are based on hydraulic-geometry relations are high relative to measured values. The estimating equation developed from measured velocities provides estimates of average reach velocity that are closer to measured velocities than are those computed using equations developed from hydraulic-geometry relations.

  10. Gulf of Aqaba, Sinai Peninsula

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The Gulf of Aqaba separates the Sinai peninsula from Saudi Arabia in this scene of the Middle East (29.0N, 34.5E) showing the geomorphology and geology of this region including portions of Egypt, Israel, Jordon and Saudi Arabia. A small portion of the Gulf of Suez can be seen on the opposite side of the Sinai peninsula.

  11. Differences in phosphorus and nitrogen delivery to the Gulf of Mexico from the Mississippi River Basin

    USGS Publications Warehouse

    Alexander, R.B.; Smith, R.A.; Schwarz, G.E.; Boyer, E.W.; Nolan, J.V.; Brakebill, J.W.

    2008-01-01

    Seasonal hypoxia in the northern Gulf of Mexico has been linked to increased nitrogen fluxes from the Mississippi and Atchafalaya River Basins, though recent evidence shows that phosphorus also influences productivity in the Gulf. We developed a spatially explicit and structurally detailed SPARROW water-quality model that reveals important differences in the sources and transport processes that control nitrogen (N) and phosphorus (P) delivery to the Gulf. Our model simulations indicate that agricultural sources in the watersheds contribute more than 70% of the delivered N and P. However, corn and soybean cultivation is the largest contributor of N (52%), followed by atmospheric deposition sources (16%); whereas P originates primarily from animal manure on pasture and rangelands (37%), followed by corn and soybeans (25%), other crops (18%), and urban sources (12%). The fraction of in-stream P and N load delivered to the Gulf increases with stream size, but reservoir trapping of P causes large local- and regional-scale differences in delivery. Our results indicate the diversity of management approaches required to achieve efficient control of nutrient loads to the Gulf. These include recognition of important differences in the agricultural sources of N and P, the role of atmospheric N, attention to P sources downstream from reservoirs, and better control of both N and P in close proximity to large rivers. ?? 2008 American Chemical Society.

  12. Differences in phosphorus and nitrogen delivery to the Gulf of Mexico from the Mississippi River Basin.

    PubMed

    Alexander, Richard B; Smith, Richard A; Schwarz, Gregory E; Boyer, Elizabeth W; Nolan, Jacqueline V; Brakebill, John W

    2008-02-01

    Seasonal hypoxia in the northern Gulf of Mexico has been linked to increased nitrogen fluxes from the Mississippi and Atchafalaya River Basins, though recent evidence shows that phosphorus also influences productivity in the Gulf. We developed a spatially explicit and structurally detailed SPARROW water-quality model that reveals important differences in the sources and transport processes that control nitrogen (N) and phosphorus (P) delivery to the Gulf. Our model simulations indicate that agricultural sources in the watersheds contribute more than 70% of the delivered N and P. However, corn and soybean cultivation is the largest contributor of N (52%), followed by atmospheric deposition sources (16%); whereas P originates primarily from animal manure on pasture and rangelands (37%), followed by corn and soybeans (25%), other crops (18%), and urban sources (12%). The fraction of in-stream P and N load delivered to the Gulf increases with stream size, but reservoir trapping of P causes large local- and regional-scale differences in delivery. Our results indicate the diversity of management approaches required to achieve efficient control of nutrient loads to the Gulf. These include recognition of important differences in the agricultural sources of N and P, the role of atmospheric N, attention to P sources downstream from reservoirs, and better control of both N and P in close proximity to large rivers.

  13. Inventory of miscellaneous streams

    SciTech Connect

    Haggard, R.D.

    1998-08-14

    Miscellaneous streams discharging to the soil column on the Hanford Site are subject to requirements of several milestones identified in Consent Order No. DE 9INM-177 (Ecology and DOE 1991). The Plan and Schedule for Disposition and Regulatory Compliance for Miscellaneous Stream (DOE/RL-93-94) provides a plan and schedule for the disposition of miscellaneous streams to satisfy one of the Section 6.0 requirements of the Consent Order. One of the commitments (Activity 6-2.2) established in the plan and schedule is to annually update, the miscellaneous streams inventory. This document constitutes the 1998 revision of the miscellaneous streams inventory. Miscellaneous stream discharges were grouped into four permitting categories (Table 1). The first miscellaneous streams Permit (ST 4508) was issued May 30, 1997, to cover wastewater discharges from hydrotesting, maintenance, and construction activities. The second miscellaneous streams Permit (ST4509) covers discharges from cooling water and condensate discharges. The third permit application for category three waste streams was eliminated by recategorizing waste streams into an existing miscellaneous streams permit or eliminating stream discharges. Elimination of the third categorical permit application was approved by Ecology in January 1997 (Ecology 1997). The fourth permit application, to cover storm water, is due to Ecology in September 1998. Table 1 provides a history of the miscellaneous streams permitting activities.

  14. Nested Gulf of Mexico Modeling with HYCOM

    DTIC Science & Technology

    2004-10-29

    Gulf of Mexico Modeling with HYCOM Patrick J. Hogan1 Alan J. Wallcraft1 Ole Martin Smedstad2 1Naval Research Laboratory Stennis Space Center...2004 4. TITLE AND SUBTITLE Nested Gulf of Mexico Modeling with HYCOM 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S...Running Nested Gulf of Mexico • 1/12° Assimilative Nested Gulf of Mexico 1/25° Free-Running Nested Gulf of Mexico

  15. Mississippi State Universitys Gulf Community Design Studio Receives First Place EPA Gulf Guardian Award

    EPA Pesticide Factsheets

    ATLANTA - The U.S. Environmental Protection Agency's (EPA) Gulf of Mexico Program recognized Mississippi State University's Gulf Community Design Studio (GCCDS) in Biloxi, Miss. with a First Place 2015 Gulf Guardian Award in the Civic/Non-Profit Cat

  16. End-to-End Commitment

    NASA Technical Reports Server (NTRS)

    Newcomb, John

    2004-01-01

    The end-to-end test would verify the complex sequence of events from lander separation to landing. Due to the large distances involved and the significant delay time in sending a command and receiving verification, the lander needed to operate autonomously after it separated from the orbiter. It had to sense conditions, make decisions, and act accordingly. We were flying into a relatively unknown set of conditions-a Martian atmosphere of unknown pressure, density, and consistency to land on a surface of unknown altitude, and one which had an unknown bearing strength.

  17. Regex-Stream

    SciTech Connect

    Goodall, John

    2012-09-01

    Log files are typically semi-or un-structured. To be useable, they need to be parsed into a standard, structured format. Regex-Stream facilitates parsing text files into structured data (JSON) in streams of data.

  18. Prioritized Contact Transport Stream

    NASA Technical Reports Server (NTRS)

    Hunt, Walter Lee, Jr. (Inventor)

    2015-01-01

    A detection process, contact recognition process, classification process, and identification process are applied to raw sensor data to produce an identified contact record set containing one or more identified contact records. A prioritization process is applied to the identified contact record set to assign a contact priority to each contact record in the identified contact record set. Data are removed from the contact records in the identified contact record set based on the contact priorities assigned to those contact records. A first contact stream is produced from the resulting contact records. The first contact stream is streamed in a contact transport stream. The contact transport stream may include and stream additional contact streams. The contact transport stream may be varied dynamically over time based on parameters such as available bandwidth, contact priority, presence/absence of contacts, system state, and configuration parameters.

  19. Central Saudi Arabia, Persian Gulf

    NASA Technical Reports Server (NTRS)

    1992-01-01

    This panoramic view of Central Saudi Arabia and the Persian Gulf (28.0N, 47.0E) dramatically illustrates the stark beauty of the deserts. Riyadh, the capital city, lies in the foreground, with the Persian Gulf in the middle and Iran in the background. The coastal oil terminals of Al Hufuf and Ad Dammam are also visible. Black smudges of soot from the oil fires set during the Gulf War can be seen on the sands to the north and south of Kuwait City.

  20. Holocene record of slip-predictable earthquakes on the Kenchreai Fault, Gulf of Corinth, Greece

    NASA Astrophysics Data System (ADS)

    Koukouvelas, Ioannis K.; Zygouri, Vasiliki; Papadopoulos, Gerasimos A.; Verroios, Sotiris

    2017-01-01

    We present the Quaternary slip history of the Kenchreai Fault, Gulf of Corinth, based on geomorphological, palaeoseismological, geo-archaeological data and literally determined events. We also applied a series of geomorphic indices such as the hypsometric curve, asymmetry factor, the stream length-gradient index (SL), the valley floor width to valley height ratio (Vf), the drainage basin shape (Bs) and the mountain-front sinuosity (Smf), in drainage basins flowing perpendicular to the fault. These indices are representative for longer time period and are analyzed as follows. Values of SL are relatively high close to the fault trace. Smf values range from 1.01 to 1.85. Vf mean values range between 0.29 and 1.07. Bs values range from 1.16 to 4.78. Lateral fault growth was likely achieved by propagation primarily towards east while its western end appears to act as persistent barrier. The Holocene palaeoseismic history of the fault investigated by a palaeoseismological trench and 14C dating of ten samples suggest four linear morphogenic earthquakes in the last 10 ka. The Kenchreai Fault displays a Holocene slip rate in the order of 0.15 mm a-1 and a recurrence interval ranging between 1300 and 4700 years. Thus the fault is classified as a fault of moderate activity with moderate to well-developed geomorphic evidence of activity and an overall slip-predictable earthquake model.

  1. Floodplain restoration enhances denitrification and reach-scale nitrogen removal in an agricultural stream

    EPA Science Inventory

    Streams of the agricultural Midwest export large quantities of nitrogen, which impairs downstream water quality, most notably in the Gulf of Mexico. The two-stage ditch is a novel restoration practice, in which floodplains are constructed alongside channelized ditches. During hi...

  2. Persistent Temporal Streams

    NASA Astrophysics Data System (ADS)

    Hilley, David; Ramachandran, Umakishore

    Distributed continuous live stream analysis applications are increasingly common. Video-based surveillance, emergency response, disaster recovery, and critical infrastructure protection are all examples of such applications. They are characterized by a variety of high- and low-bandwidth streams as well as a need for analyzing both live and archived streams. We present a system called Persistent Temporal Streams (PTS) that supports a higher-level, domain-targeted programming abstraction for such applications. PTS provides a simple but expressive stream abstraction encompassing transport, manipulation and storage of streaming data. In this paper, we present a system architecture for implementing PTS. We provide an experimental evaluation which shows the system-level primitives can be implemented in a lightweight and high-performance manner, and an application-based evaluation designed to show that a representative high-bandwidth stream analysis application can be implemented relatively simply and with good performance.

  3. Method for removing particulate matter from a gas stream

    DOEpatents

    Postma, Arlin K.

    1984-01-01

    Particulate matter is removed from a stream of pressurized gas by directing the stream of gas upwardly through a bed of porous material, the porous bed being held in an open ended container and at least partially submerged in liquid. The passage of the gas through the porous bed sets up a circulation in the liquid which cleans the particulate matter from the bed.

  4. Holocene aridity and storm phases, Gulf and Atlantic coasts, USA

    NASA Astrophysics Data System (ADS)

    Otvos, Ervin G.

    2005-05-01

    A bottomland flora that prevailed between ˜9900 and 6000 cal yr B.P. in a North Carolina stream valley may not reflect a regionally much wetter Atlantic climate, coeval with record drought in the Great Plains region and assumed dry Gulf coastal conditions. Such conditions were inferred for 6000 ± 1000 yr ago when the Bermuda High may have consistently occupied summer positions far to the NE. Arid episodes coeval with the Little River local wet interval are known from eolian sediments and pollen spectra in the Atlantic and the Gulf coastal plain. For multiple reasons, the regional extent, intensity, and duration of coastal aridity and alternating wet phases and the Bermuda High positions are not yet adequately constrained. The climate and edaphic causes for the steadily growing predominance of southern pines over hardwoods, achieved between ˜8900 and 4200 cal yr B.P. at different sites at different times are similarly still unresolved. New data from Shelby Lake, AL, reconfirms that no credible field or other proxy evidence exists for a previously postulated "catastrophic Gulf hurricane phase" in the late Holocene.

  5. Gas stream purifier

    NASA Technical Reports Server (NTRS)

    Adam, Steven J.

    1994-01-01

    A gas stream purifier has been developed that is capable of removing corrosive acid, base, solvent, organic, inorganic, and water vapors as well as particulates from an inert mixed gas stream using only solid scrubbing agents. This small, lightweight purifier has demonstrated the ability to remove contaminants from an inert gas stream with a greater than 99 percent removal efficiency. The Gas Stream Purifier has outstanding market and sales potential in manufacturing, laboratory and science industries, medical, automotive, or any commercial industry where pollution, contamination, or gas stream purification is a concern. The purifier was developed under NASA contract NAS9-18200 Schedule A for use in the international Space Station. A patent application for the Gas Stream Purifier is currently on file with the United States Patent and Trademark Office.

  6. Upper Paleocene and lowermost Eocene angiosperm pollen biostratigraphy of the eastern Gulf Coast and Virginia

    USGS Publications Warehouse

    Frederiksen, N.O.

    1998-01-01

    Strata comprising most of the upper Paleocene in eastern North America are divided into two new pollen zones, the Carya and Platycarya platycaryoides Interval Zones. Pollen data have proven to be important for correlations between Alabama-western Georgia and eastern Mississippi and between the eastern Gulf Coast and Virginia. Migration of tropical plant taxa from the Caribbean to the Gulf Coast began at least 4 m.y. before the end of the Paleocene. The Terminal Paleocene Extinction Event, accompanied by a distinct pulse of plant immigration from Europe, began several hundred thousand years before the end of the Paleocene.

  7. Probiotic (VSL#3) for Gulf War Illness

    DTIC Science & Technology

    2011-10-01

    Changes in Fecal Microbiota of Gulf War Veterans with Irritable Bowel Syndrome. I was invited to write an editorial in the journal of Digestive...8 Appendices Abstract (Presented at the Digestive Disease Week Changes in Fecal Microbiota of Gulf

  8. Inventory of miscellaneous streams

    SciTech Connect

    Lueck, K.J.

    1995-09-01

    On December 23, 1991, the US Department of Energy, Richland Operations Office (RL) and the Washington State Department of Ecology (Ecology) agreed to adhere to the provisions of the Department of Ecology Consent Order. The Consent Order lists the regulatory milestones for liquid effluent streams at the Hanford Site to comply with the permitting requirements of Washington Administrative Code. The RL provided the US Congress a Plan and Schedule to discontinue disposal of contaminated liquid effluent into the soil column on the Hanford Site. The plan and schedule document contained a strategy for the implementation of alternative treatment and disposal systems. This strategy included prioritizing the streams into two phases. The Phase 1 streams were considered to be higher priority than the Phase 2 streams. The actions recommended for the Phase 1 and 2 streams in the two reports were incorporated in the Hanford Federal Facility Agreement and Consent Order. Miscellaneous Streams are those liquid effluents streams identified within the Consent Order that are discharged to the ground but are not categorized as Phase 1 or Phase 2 Streams. This document consists of an inventory of the liquid effluent streams being discharged into the Hanford soil column.

  9. User aware video streaming

    NASA Astrophysics Data System (ADS)

    Kerofsky, Louis; Jagannath, Abhijith; Reznik, Yuriy

    2015-03-01

    We describe the design of a video streaming system using adaptation to viewing conditions to reduce the bitrate needed for delivery of video content. A visual model is used to determine sufficient resolution needed under various viewing conditions. Sensors on a mobile device estimate properties of the viewing conditions, particularly the distance to the viewer. We leverage the framework of existing adaptive bitrate streaming systems such as HLS, Smooth Streaming or MPEG-DASH. The client rate selection logic is modified to include a sufficient resolution computed using the visual model and the estimated viewing conditions. Our experiments demonstrate significant bitrate savings compare to conventional streaming methods which do not exploit viewing conditions.

  10. Controls on the early Holocene collapse of the Bothnian Sea Ice Stream

    NASA Astrophysics Data System (ADS)

    Clason, Caroline C.; Greenwood, Sarah L.; Selmes, Nick; Lea, James M.; Jamieson, Stewart S. R.; Nick, Faezeh M.; Holmlund, Per

    2016-12-01

    New high-resolution multibeam data in the Gulf of Bothnia reveal for the first time the subglacial environment of a Bothnian Sea Ice Stream. The geomorphological record suggests that increased meltwater production may have been important in driving rapid retreat of Bothnian Sea Ice during deglaciation. Here we apply a well-established, one-dimensional flow line model to simulate ice flow through the Gulf of Bothnia and investigate controls on retreat of the ice stream during the post-Younger Dryas deglaciation of the Fennoscandian Ice Sheet. The relative influence of atmospheric and marine forcings are investigated, with the modeled ice stream exhibiting much greater sensitivity to surface melting, implemented through surface mass balance and hydrofracture-induced calving, than to submarine melting or relative sea level change. Such sensitivity is supported by the presence of extensive meltwater features in the geomorphological record. The modeled ice stream does not demonstrate significant sensitivity to changes in prescribed ice stream width or overall bed slope, but local variations in basal topography and ice stream width result in nonlinear retreat of the grounding line, notably demonstrating points of short-lived retreat slowdown on reverse bed slopes. Retreat of the ice stream was most likely governed by increased ice surface meltwater production, with the modeled retreat rate less sensitive to marine forcings despite the marine setting.

  11. Positive mass balance of the Ross Ice Streams, West Antarctica.

    PubMed

    Joughin, Ian; Tulaczyk, Slawek

    2002-01-18

    We have used ice-flow velocity measurements from synthetic aperture radar to reassess the mass balance of the Ross Ice Streams, West Antarctica. We find strong evidence for ice-sheet growth (+26.8 gigatons per year), in contrast to earlier estimates indicating a mass deficit (-20.9 gigatons per year). Average thickening is equal to approximately 25% of the accumulation rate, with most of this growth occurring on Ice Stream C. Whillans Ice Stream, which was thought to have a significantly negative mass balance, is close to balance, reflecting its continuing slowdown. The overall positive mass balance may signal an end to the Holocene retreat of these ice streams.

  12. Gulf Petro Initiative

    SciTech Connect

    Fathi Boukadi

    2011-02-05

    In this report, technologies for petroleum production and exploration enhancement in deepwater and mature fields are developed through basic and applied research by: (1) Designing new fluids to efficiently drill deepwater wells that can not be cost-effectively drilled with current technologies. The new fluids will be heavy liquid foams that have low-density at shallow dept to avoid formation breakdown and high density at drilling depth to control formation pressure. The goal of this project is to provide industry with formulations of new fluids for reducing casing programs and thus well construction cost in deepwater development. (2) Studying the effects of flue gas/CO{sub 2} huff n puff on incremental oil recovery in Louisiana oilfields bearing light oil. An artificial neural network (ANN) model will be developed and used to map recovery efficiencies for candidate reservoirs in Louisiana. (3) Arriving at a quantitative understanding for the three-dimensional controlled-source electromagnetic (CSEM) geophysical response of typical Gulf of Mexico hydrocarbon reservoirs. We will seek to make available tools for the qualitative, rapid interpretation of marine CSEM signatures, and tools for efficient, three-dimensional subsurface conductivity modeling.

  13. Intelligent front-end sample preparation tool using acoustic streaming.

    SciTech Connect

    Cooley, Erika J.; McClain, Jaime L.; Murton, Jaclyn K.; Edwards, Thayne L.; Achyuthan, Komandoor E.; Branch, Darren W.; Clem, Paul Gilbert; Anderson, John Mueller; James, Conrad D.; Smith, Gennifer; Kotulski, Joseph Daniel

    2009-09-01

    We have successfully developed a nucleic acid extraction system based on a microacoustic lysis array coupled to an integrated nucleic acid extraction system all on a single cartridge. The microacoustic lysing array is based on 36{sup o} Y cut lithium niobate, which couples bulk acoustic waves (BAW) into the microchannels. The microchannels were fabricated using Mylar laminates and fused silica to form acoustic-fluidic interface cartridges. The transducer array consists of four active elements directed for cell lysis and one optional BAW element for mixing on the cartridge. The lysis system was modeled using one dimensional (1D) transmission line and two dimensional (2D) FEM models. For input powers required to lyse cells, the flow rate dictated the temperature change across the lysing region. From the computational models, a flow rate of 10 {micro}L/min produced a temperature rise of 23.2 C and only 6.7 C when flowing at 60 {micro}L/min. The measured temperature changes were 5 C less than the model. The computational models also permitted optimization of the acoustic coupling to the microchannel region and revealed the potential impact of thermal effects if not controlled. Using E. coli, we achieved a lysing efficacy of 49.9 {+-} 29.92 % based on a cell viability assay with a 757.2 % increase in ATP release within 20 seconds of acoustic exposure. A bench-top lysing system required 15-20 minutes operating up to 58 Watts to achieve the same level of cell lysis. We demonstrate that active mixing on the cartridge was critical to maximize binding and release of nucleic acid to the magnetic beads. Using a sol-gel silica bead matrix filled microchannel the extraction efficacy was 40%. The cartridge based magnetic bead system had an extraction efficiency of 19.2%. For an electric field based method that used Nafion films, a nucleic acid extraction efficiency of 66.3 % was achieved at 6 volts DC. For the flow rates we tested (10-50 {micro}L/min), the nucleic acid extraction time was 5-10 minutes for a volume of 50 {micro}L. Moreover, a unique feature of this technology is the ability to replace the cartridges for subsequent nucleic acid extractions.

  14. Blood Biomarkers of Chronic Inflammation in Gulf War Illness

    PubMed Central

    Johnson, Gerhard J.; Slater, Billie C. S.; Leis, Linda A.; Rector, Thomas S.; Bach, Ronald R.

    2016-01-01

    Background More than twenty years following the end of the 1990–1991 Gulf War it is estimated that approximately 300,000 veterans of this conflict suffer from an unexplained chronic, multi-system disorder known as Gulf War Illness (GWI). The etiology of GWI may be exposure to chemical toxins, but it remains only partially defined, and its case definition is based only on symptoms. Objective criteria for the diagnosis of GWI are urgently needed for diagnosis and therapeutic research. Objective This study was designed to determine if blood biomarkers could provide objective criteria to assist diagnosis of GWI. Design A surveillance study of 85 Gulf War Veteran volunteers identified from the Department of Veterans Affairs Minnesota Gulf War registry was performed. All subjects were deployed to the Gulf War. Fifty seven subjects had GWI defined by CDC criteria, and 28 did not have symptomatic criteria for a diagnosis of GWI. Statistical analyses were performed on peripheral blood counts and assays of 61 plasma proteins using the Mann-Whitney rank sum test to compare biomarker distributions and stepwise logistic regression to formulate a diagnostic model. Results Lymphocyte, monocyte, neutrophil, and platelet counts were higher in GWI subjects. Six serum proteins associated with inflammation were significantly different in GWI subjects. A diagnostic model of three biomarkers—lymphocytes, monocytes, and C reactive protein—had a predicted probability of 90% (CI 76–90%) for diagnosing GWI when the probability of having GWI was above 70%. Significance The results of the current study indicate that inflammation is a component of the pathobiology of GWI. Analysis of the data resulted in a model utilizing three readily measurable biomarkers that appears to significantly augment the symptom-based case definition of GWI. These new observations are highly relevant to the diagnosis of GWI, and to therapeutic trials. PMID:27352030

  15. Citrus waste stream utilization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Waste streams, generated during fruit processing, consist of solid fruit residues in addition to liquid waste streams from washing operations which must be handled in an environmentally acceptable manner. Unsound fruit from packing houses are usually sent off to be processed for juice and the solid ...

  16. Adopt a Stream.

    ERIC Educational Resources Information Center

    Friends of Environmental Education Society of Alberta (Edmonton).

    This environmental education program is designed to increase awareness among junior high school students of stream ecosystems and those habitats which comprise the ecosystems adjacent to streams. The teaching content of the manual is presented in two major sections. The first section provides information and background material for the group…

  17. WADEABLE STREAMS ASSESSMENT

    EPA Science Inventory

    This Wadeable Streams Assessment (WSA) provides the first statistically defensible summary of the condition of the nation’s streams and small rivers, which are so integrally tied to our history. This report brings the results of this ground-breaking study to the American public....

  18. VLBI2010 Receiver Back End Comparison

    NASA Technical Reports Server (NTRS)

    Petrachenko, Bill

    2013-01-01

    VLBI2010 requires a receiver back-end to convert analog RF signals from the receiver front end into channelized digital data streams to be recorded or transmitted electronically. The back end functions are typically performed in two steps: conversion of analog RF inputs into IF bands (see Table 2), and conversion of IF bands into channelized digital data streams (see Tables 1a, 1b and 1c). The latter IF systems are now completely digital and generically referred to as digital back ends (DBEs). In Table 2 two RF conversion systems are compared, and in Tables 1a, 1b, and 1c nine DBE systems are compared. Since DBE designs are advancing rapidly, the data in these tables are only guaranteed to be current near the update date of this document.

  19. A Stochastic-Dynamic Data Assimilation Strategy Applied to Return Flow over the Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Lewis, J. M.

    2013-12-01

    A Lagrangian convective air/sea interaction model is used to make ensemble (Monte Carlo) forecasts of return flow over the Gulf of Mexico. This model is especially appropriate for wintertime conditions over the Gulf when the sea surface temperature is generally 5-10C warmer than the continental air that streams over the Gulf in cold air outflow. In the absence of routine upper-air observations over the Gulf, a premier set of observations collected during the field program GUFMEX is used for the study. Uncertainty in both initial conditions and forcing (turbulence and entrainment parameterization) contribute to the structure of the model's probability density function (pdf). A sequential data assimilation scheme is used to optimally estimate model variables based on a variational principle that incorporates the variance/covariance of model error and error variance of observations.Results indicate that buoy-based measurements of air temperature, vapor mixing ratio, and sea surface temperature in concert with the model pdf serve to give reasonable estimates of the height of the convective layer. This result holds promise for improving the operational forecast of return flow over the Gulf in wintertime.

  20. Evidence against a late Wisconsinan ice shelf in the Gulf of Maine

    USGS Publications Warehouse

    Oldale, R.N.; Williams, R.S.; Colman, Steven M.

    1990-01-01

    Proposals for the formation of a late Wisconsinan ice shelf in the Gulf of Maine during the retreat of the Laurentide Ice Sheet are considered to be inappropriate. An Antarctic-type ice shelf does not fit the field data that indicate temperate glacial, terrestrial, and marine climates for the region between 18 ka and 12 ka. A temperate ice shelf has no modern analogues and may be physically impossible. The preponderance of stratified drift in the Gulf of Maine region supports temperate climates during late Wisconsinan time. It also indicates that glacial meltwater, rather than ice in either an ice sheet or ice shelf, was the primary transport mechanism of glacial sediment and the source for the glaciomarine mud. For these reasons we have proposed glacial analogues for the deglaciation of the Gulf of Maine that consist of temperate or subpolar marine-based glaciers, characterized by depositional environments dominated by meltwater discharge directly to the sea or the sea by way of subaerial meltwater streams. These analogues include Alaskan fjord glaciers, glaciers on the Alaskan continental shelf that discharged meltwater directly into the sea in the not too distant past, and Austfonna (Nordaustandet, Svalbard, Norway) that is presently discharging meltwater in the sea along a grounded ice wall. This last example is the best modern-day analogue for the depositional environment for most of the glaciomarine mud in the Gulf of Maine and deglaciation of the Gulf. ?? 1990.

  1. The USGS and the Gulf of Mexico

    USGS Publications Warehouse

    Dausman, Alyssa M.; Spear, Kate

    2009-01-01

    The U.S. Geological Survey (USGS) is committed to mapping, monitoring, and conducting research in the Gulf of Mexico and adjacent watersheds. Through a network of science centers in the five Gulf States and across the Nation, the USGS applies its biologic, geologic, geographic, and hydrologic expertise to provide unbiased scientific findings to decisionmakers, particularly members and supporters of the Gulf of Mexico Alliance (Gulf Alliance). The overarching goal of USGS Gulf Coast activities is to provide the scientific information, knowledge, and tools required to facilitate management decisions that promote restoration, increase coastal resilience, and mitigate risks associated with both artificial and natural hazards.

  2. Concept of Security for Gulf States After Gulf War

    DTIC Science & Technology

    2007-11-02

    112 27 Ibid page 113 28 Ibid pages 114-115 29 Abdul Munam Al Mashad Towards The ArabicFormula for The National Security Theory Dar Al Mustaqbil...Search For Strategic Stability. England: Mansell Publishing, 1985 Noyes, James H. The Persian Gulf After The Cold War. Westport, CT, 1984 Al Mashad

  3. Geographic variation in the molluscan recovery from the end-cretaceous extinction

    PubMed

    Jablonski

    1998-02-27

    Biotic recovery patterns after the end-Cretaceous mass extinction differ among the molluscan faunas of the North American Gulf Coast, northern Europe, northern Africa, and Pakistan and northern India. In contrast to the Gulf Coast, the other three regions lack a rapid expansion and decline of "bloom taxa" and have lower proportions of invaders early in the recovery phase. The anomalous Gulf Coast patterns, distinct from extratropical Europe and the tropical regions, provide evidence for the biogeographic and macroevolutionary complexity of biotic recoveries and may have implications for present-day biotas.

  4. Intermediate-depth circulation in the Gulf of Mexico estimated from direct measurements

    NASA Astrophysics Data System (ADS)

    Weatherly, Georges L.; Wienders, Nicolas; Romanou, Anastasia

    Data from 17 PALACE floats set in the Gulf of Mexico sampling the intermediate-depth (≈900 dbar) flow from April 1998 to February 2002 indicate a mean cyclonic circulation along the northern and western edges of the Gulf of Mexico. This flow intensified into a ≈0.10 m/s current in the western Bay of Campeche and was deflected around a topographic feature, called here the Campeche Bay Bump, in the southern Bay of Campeche. Floats launched in the eastern Gulf of Mexico tended to stay there, and those launched in the western Gulf tended to stay in the western Gulf, suggesting restricted connection at depth between the eastern and western Gulf of Mexico. Not surprisingly, the measured flow was stronger when the measured flow was under the Loop Current and warm-core rings, but the direction of the intermediated depth currents bore no apparent relation to the surface flow inferred from satellite altimeter maps. However, comparing the floats' surface drifts to their intermediate depth drifts, the floats at depth ended to track the surface flow in the Loop Current, and both indicate a cyclonic gyre in the Bay of Campeche.

  5. Stream air temperature relations to classify stream ground water interactions in a karst setting, central Pennsylvania, USA

    NASA Astrophysics Data System (ADS)

    O'Driscoll, Michael A.; DeWalle, David R.

    2006-09-01

    SummaryStream-ground water interactions in karst vary from complete losses through swallow holes, to reemergences from springs. Our study objective was to compare stream-air temperature and energy exchange relationships across various stream-ground water relationships in a carbonate watershed. It was hypothesized that ground water-fed stream segments could be distinguished from perched/losing segments using stream-air temperature relationships. Two types of computations were conducted: (1) comparisons of stream-air temperature relationships for the period of October 1999-September 2002 at 12 sites in the Spring Creek drainage and (2) detailed energy budget computations for the same period for ground water-dominated Thompson Run and Lower Buffalo Run, a stream with negligible ground water inputs. Weekly average air temperatures and stream temperatures were highly correlated, but slopes and intercepts of the relationship varied for the 12 sites. Slopes ranged from 0.19 to 0.67 and intercepts ranged from 3.23 to 9.07 °C. A two-component mixing model with end members of ground water and actual stream temperatures indicated that the slope and intercept of the stream-air temperature relationship was controlled by ground water inputs. Streams with large ground water inputs had greater intercepts and lesser slopes than streams that were seasonally losing, perched, and/or distant from ground water inputs. Energy fluxes across the air-water interface were greatest for the ground water-fed stream due to increased longwave, latent, and sensible heat losses from the stream in winter when large temperature and vapor pressure differences existed between the stream and air. Advection of ground water was an important source and sink for heat in the ground water-fed stream, depending on season. In contrast, along the seasonally losing stream reach, advection was of minimal importance and stream temperatures were dominated by energy exchange across the air- water interface. Overall

  6. Wadeable Streams Assessment Data

    EPA Pesticide Factsheets

    The Wadeable Streams Assessment (WSA) is a first-ever statistically-valid survey of the biological condition of small streams throughout the U.S. The U.S. Environmental Protection Agency (EPA) worked with the states to conduct the assessment in 2004-2005. Data for each parameter sampled in the Wadeable Streams Assessment (WSA) are available for downloading in a series of files as comma separated values (*.csv). Each *.csv data file has a companion text file (*.txt) that lists a dataset label and individual descriptions for each variable. Users should view the *.txt files first to help guide their understanding and use of the data.

  7. Twitter Stream Archiver

    SciTech Connect

    Steed, Chad Allen

    2014-07-01

    The Twitter Archiver system allows a user to enter their Twitter developer account credentials (obtained separately from the Twitter developer website) and read from the freely available Twitter sample stream. The Twitter sample stream provides a random sample of the overall volume of tweets that are contributed by users to the system. The Twitter Archiver system consumes the stream and serializes the information to text files at some predefined interval. A separate utility reads the text files and creates a searchable index using the open source Apache Lucene text indexing system.

  8. 50 CFR 622.25 - Exemptions for Gulf groundfish trawling.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE FISHERIES OF THE CARIBBEAN, GULF OF MEXICO, AND SOUTH ATLANTIC Reef Fish Resources of the Gulf of Mexico § 622.25 Exemptions for Gulf groundfish trawling. Gulf... 50 Wildlife and Fisheries 12 2014-10-01 2014-10-01 false Exemptions for Gulf groundfish...

  9. Online Visual Analytics of Text Streams.

    PubMed

    Liu, Shixia; Yin, Jialun; Wang, Xiting; Cui, Weiwei; Cao, Kelei; Pei, Jian

    2016-11-01

    We present an online visual analytics approach to helping users explore and understand hierarchical topic evolution in high-volume text streams. The key idea behind this approach is to identify representative topics in incoming documents and align them with the existing representative topics that they immediately follow (in time). To this end, we learn a set of streaming tree cuts from topic trees based on user-selected focus nodes. A dynamic Bayesian network model has been developed to derive the tree cuts in the incoming topic trees to balance the fitness of each tree cut and the smoothness between adjacent tree cuts. By connecting the corresponding topics at different times, we are able to provide an overview of the evolving hierarchical topics. A sedimentation-based visualization has been designed to enable the interactive analysis of streaming text data from global patterns to local details. We evaluated our method on real-world datasets and the results are generally favorable.

  10. Academics in the Persian Gulf

    ERIC Educational Resources Information Center

    Mills, Andrew

    2009-01-01

    The job market on North American campuses may be heading for the deep freeze, but hundreds of positions are opening up in the Persian Gulf as American universities scramble to set down roots in those petrodollar-rich states. The combination of money and opportunity on offer may seem hard to resist. But academics who trade the rich intellectual…

  11. Pakistan and the Persian Gulf

    DTIC Science & Technology

    1991-04-25

    generally. 1 6 The exact figures are difficult to assess as 12 there are a large number of illegal imigrants also in various Gulf states. The breakdown of...having least or no presence of outsiders. War cannot be eliminated from relations between states any more than crime can be eliminated from human society

  12. Gulf War Illness Research Program

    DTIC Science & Technology

    2010-01-01

    neurofibromato- sis; autism ; and other areas with military health interests including psychological health, traumatic brain injury, and Gulf War Illness (GWI...the national news headlines, it has not dimmed our hope that treatments and cures for GWI are waiting to be discovered and brought to bear against

  13. Horizontal transport and seasonal distribution of nutrients, dissolved oxygen and chlorophyll -a in the Gulf of Nicoya, Costa Rica: a tropical estuary

    NASA Astrophysics Data System (ADS)

    Kress, Nurit; Coto, Sandra Leon; Brenes, Carlos L.; Brenner, Stephen; Arroyo, Guillermo

    2002-01-01

    The distributions of salinity, temperature, nutrients, dissolved oxygen and chlorophyll -a (chl -a) concentrations in the Gulf of Nicoya, Costa Rica, during the rainy and dry seasons are presented. In the rainy season, the entire Gulf is strongly stratified due to high riverine discharge; surface temperature decreases and salinity increases towards the sea and most of the Gulf is undersaturated with dissolved oxygen. In the dry season, the Gulf is still stratified although without the strong fresh water signal identified in the rainy season. The lowest surface temperatures appear in the middle of the Gulf whilst the salinity generally decreases towards the upper Gulf. Only the deep waters (below 30 m depth) are undersaturated with dissolved oxygen. In the lower Gulf, oversaturation reaches up to 134% at the surface. The concentration of Si(OH) 4 in the Gulf is much higher during the rainy season than in the dry season, whilst PO 4 is not seasonally dependent. Surficial concentrations of NO 3+NO 2 in the upper Gulf are higher in the dry season than in the rainy season; whilst in most of the lower Gulf, the concentrations are lower in the dry season. Surficial chl -a concentrations in the Gulf are higher in the rainy season, in particular, close to the Tarcoles outflow. A three-component mixing diagram describes the spatial distribution of the nutrients, during both seasons. Riverine waters from the Tempisque (high nutrients and low salinity) are mixed with surface waters from the lower Gulf (higher salinity and lower nutrients). The resulting water then mixes with oceanic water. Salinity in relation to PO 4 is seasonally dependent in the upper Gulf; the riverine end member during the dry season is higher, by a factor of 4, than during the rainy season. There is a significant correlation between NO 3+NO 2 and salinity only during the dry season in the upper Gulf; this is probably a result of phytoplankton consumption of N, in the rainy season. The calculated NO 3+NO

  14. 76 FR 23909 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Gulf of Mexico Reef Fish Fishery...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-29

    ..., Gulf of Mexico, and South Atlantic; Gulf of Mexico Reef Fish Fishery; 2011 Accountability Measures for Greater Amberjack and Closure of the 2011 Gulf of Mexico Commercial Sector for Greater Amberjack AGENCY... Reef Fish Resources of the Gulf of Mexico (FMP). The FMP was prepared by the Gulf of Mexico......

  15. 76 FR 68339 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Reef Fish Fishery of the Gulf of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-04

    ..., Gulf of Mexico, and South Atlantic; Reef Fish Fishery of the Gulf of Mexico; Amendment 26 and Amendment... commercial sector of the reef fish fishery in the Gulf of Mexico (Gulf) exclusive economic zone (EEZ... . SUPPLEMENTARY INFORMATION: The reef fish fishery of the Gulf of Mexico is managed under the FMP.......

  16. 75 FR 15665 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Reef Fish Fishery of the Gulf of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-30

    ..., Gulf of Mexico, and South Atlantic; Reef Fish Fishery of the Gulf of Mexico; Red Snapper Management.... SUPPLEMENTARY INFORMATION: The reef fish fishery of the Gulf of Mexico is managed under the FMP. The FMP was... of the Gulf of Mexico (FMP) prepared by the Gulf of Mexico Fishery Management Council......

  17. 75 FR 54965 - Proposed Information Collection (Follow-Up Study of a National Cohort of Gulf War and Gulf Era...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-09

    ... AFFAIRS Proposed Information Collection (Follow-Up Study of a National Cohort of Gulf War and Gulf Era... problems of Gulf War Veterans. DATES: Written comments and recommendations on the proposed collection of...: Follow-Up Study of a National Cohort of Gulf War and Gulf Era Veterans, VA Form 10-0488, and Consent...

  18. 75 FR 70365 - Agency Information Collection (Follow-Up Study of a National Cohort of Gulf War and Gulf Era...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-17

    ... AFFAIRS Agency Information Collection (Follow-Up Study of a National Cohort of Gulf War and Gulf Era... National Cohort of Gulf War and Gulf Era Veterans, VA Form 10-0488 and Consent Form for Release of Medical.... Abstracts: a. The data collected on VA Form 10-0488, will help VA to assess the health of Gulf War...

  19. 75 FR 54445 - Proposed Information Collection (Follow-Up Study of a National Cohort of Gulf War and Gulf Era...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-07

    ... AFFAIRS Proposed Information Collection (Follow-Up Study of a National Cohort of Gulf War and Gulf Era... problems of Gulf War Veterans. DATES: Written comments and recommendations on the proposed collection of...: Follow-Up Study of a National Cohort of Gulf War and Gulf Era Veterans, VA Form 10-0488, and Consent...

  20. Urban Stream Ecology

    EPA Science Inventory

    Urban watersheds characteristically have high impervious surface cover, resulting in high surface runoff and low infiltration following storms. In response, urban streams experience “flashy” stormflows, reduced baseflows, bank erosion, channel widening, and sedimentation. Urban ...

  1. Stochastic ice stream dynamics

    NASA Astrophysics Data System (ADS)

    Mantelli, Elisa; Bertagni, Matteo Bernard; Ridolfi, Luca

    2016-08-01

    Ice streams are narrow corridors of fast-flowing ice that constitute the arterial drainage network of ice sheets. Therefore, changes in ice stream flow are key to understanding paleoclimate, sea level changes, and rapid disintegration of ice sheets during deglaciation. The dynamics of ice flow are tightly coupled to the climate system through atmospheric temperature and snow recharge, which are known exhibit stochastic variability. Here we focus on the interplay between stochastic climate forcing and ice stream temporal dynamics. Our work demonstrates that realistic climate fluctuations are able to (i) induce the coexistence of dynamic behaviors that would be incompatible in a purely deterministic system and (ii) drive ice stream flow away from the regime expected in a steady climate. We conclude that environmental noise appears to be crucial to interpreting the past behavior of ice sheets, as well as to predicting their future evolution.

  2. Streaming tearing mode

    NASA Technical Reports Server (NTRS)

    Shigeta, M.; Sato, T.; Dasgupta, B.

    1985-01-01

    The magnetohydrodynamic stability of streaming tearing mode is investigated numerically. A bulk plasma flow parallel to the antiparallel magnetic field lines and localized in the neutral sheet excites a streaming tearing mode more strongly than the usual tearing mode, particularly for the wavelength of the order of the neutral sheet width (or smaller), which is stable for the usual tearing mode. Interestingly, examination of the eigenfunctions of the velocity perturbation and the magnetic field perturbation indicates that the streaming tearing mode carries more energy in terms of the kinetic energy rather than the magnetic energy. This suggests that the streaming tearing mode instability can be a more feasible mechanism of plasma acceleration than the usual tearing mode instability.

  3. Stochastic ice stream dynamics

    PubMed Central

    Bertagni, Matteo Bernard; Ridolfi, Luca

    2016-01-01

    Ice streams are narrow corridors of fast-flowing ice that constitute the arterial drainage network of ice sheets. Therefore, changes in ice stream flow are key to understanding paleoclimate, sea level changes, and rapid disintegration of ice sheets during deglaciation. The dynamics of ice flow are tightly coupled to the climate system through atmospheric temperature and snow recharge, which are known exhibit stochastic variability. Here we focus on the interplay between stochastic climate forcing and ice stream temporal dynamics. Our work demonstrates that realistic climate fluctuations are able to (i) induce the coexistence of dynamic behaviors that would be incompatible in a purely deterministic system and (ii) drive ice stream flow away from the regime expected in a steady climate. We conclude that environmental noise appears to be crucial to interpreting the past behavior of ice sheets, as well as to predicting their future evolution. PMID:27457960

  4. Satellite/Terrestrial Networks: End-to-End Communication Interoperability Quality of Service Experiments

    NASA Technical Reports Server (NTRS)

    Ivancic, William D.

    1998-01-01

    Various issues associated with satellite/terrestrial end-to-end communication interoperability are presented in viewgraph form. Specific topics include: 1) Quality of service; 2) ATM performance characteristics; 3) MPEG-2 transport stream mapping to AAL-5; 4) Observation and discussion of compressed video tests over ATM; 5) Digital video over satellites status; 6) Satellite link configurations; 7) MPEG-2 over ATM with binomial errors; 8) MPEG-2 over ATM channel characteristics; 8) MPEG-2 over ATM over emulated satellites; 9) MPEG-2 transport stream with errors; and a 10) Dual decoder test.

  5. Android Video Streaming

    DTIC Science & Technology

    2014-05-01

    Android Video Streaming by Jonathan Fletcher, David Doria, and David Bruno ARL-TR-6947 May 2014...the originator. Army Research Laboratory Aberdeen Proving Ground, MD 21005-5067 ARL-TR-6947 May 2014 Android Video Streaming...1. REPORT DATE (DD-MM-YYYY) May 2014 2. REPORT TYPE Final 3. DATES COVERED (From - To) July 2013–September 2013 4. TITLE AND SUBTITLE Android

  6. Hydrologic changes in urban streams and their ecological significance

    USGS Publications Warehouse

    Konrad, C.P.; Booth, D.B.

    2005-01-01

    Urban development modifies the production and delivery of runoff to streams and the resulting rate, volume, and timing of streamflow. Given that streamflow demonstrably influences the structure and composition of lotic communities, we have identified four hydrologic changes resulting from urban development that are potentially significant to stream ecosystems: increased frequency of high flows, redistribution of water from base flow to storm flow, increased daily variation in streamflow, and reduction in low flow. Previous investigations of streamflow patterns and biological assemblages provide a scale of ecological significance for each type of streamflow pattern. The scales establish the magnitude of changes in streamflow patterns that could be expected to produce biological responses in streams. Long-term streamflow records from eight streams in urbanizing areas of the United States and five additional reference streams, where land use has been relatively stable, were analyzed to assess if streamflow patterns were modified by urban development to an extent that a biological response could be expected and whether climate patterns could account for equivalent hydrologic variation in the reference streams. Changes in each type of streamflow pattern were evident in some but not all of the urban streams and were nearly absent in the reference streams. Given these results, hydrologic changes are likely significant to urban stream ecosystems, but the significance depends on the stream's physiographic context and spatial and temporal patterns of urban development. In urban streams with substantially altered hydrology, short-term goals for urban stream rehabilitation may be limited because of the difficulty and expense of restoring hydrologic processes in an urban landscape. The ecological benefits of improving physical habitat and water quality may be tempered by persistent effects of altered streamflow. In the end, the hydrologic effects of urban development must be

  7. A primeval Magellanic Stream and others

    SciTech Connect

    Peebles, P. J. E.; Tully, R. Brent

    2013-12-01

    The Magellanic Stream (MS) might have grown out of tidal interactions at high redshift, when the young galaxies were close together, rather than from later interactions among the Magellanic Clouds and Milky Way (MW). This is illustrated in solutions for the orbits of Local Group (LG) galaxies under the cosmological condition of growing peculiar velocities at high redshift. Massless test particles initially near and moving with the Large Magellanic Cloud in these solutions end up with distributions in angular position and redshift similar to the MS, though with the usual overly prominent leading component that the MW corona might have suppressed. Another possible example of the effect of conditions at high redshift is a model primeval stream around the LG galaxy NGC 6822. Depending on the solution for LG dynamics, this primeval stream can end up with a position angle similar to the H I around this galaxy and a redshift gradient in the observed direction. The gradient is much smaller than observed but might have been increased by dissipative contraction. Presented also is an even more speculative illustration of the possible effect of initial conditions, primeval stellar streams around M31.

  8. Review of the circulation in the Beibu Gulf, South China Sea

    NASA Astrophysics Data System (ADS)

    Gao, Jingsong; Wu, Guidan; Ya, Hanzheng

    2017-04-01

    Although Beibu Gulf holds a significant geographical location and is rich in fishery resources, it has attracted only limited attention from researchers in recent decades. This study summarizes the conclusions based on the observations and model results regarding the circulation and cold water mass in the Beibu Gulf to provide a reference for further research. Affected by wind and density gradient, the spring circulation may be gulf-scale cyclonic and nested with an enclosed cyclonic gyre in the northern gulf and unclosed cyclonic gyre in the southern gulf. Meanwhile, the mechanisms of summer circulation remain controversial. Along with the results of a new numerical model, historical observations suggest that summer circulation is cyclonic and anticyclonic in the northern and southern gulfs, respectively. The northern and southern gulfs are mainly influenced by wind stress curl and South China Sea current, respectively. Similarly, although different views regarding the structure of winter circulation have been presented, a large amount of evidence supports the existence of two cyclonic gyres in the northern and southern gulfs. In addition, a southwestward current off the northwestern coast of Hainan Island is present. The circulation structure in the fall is similar to that in winter. However, the cyclonic gyre in the southern Gulf has a greater tendency to intrude northwards into the Beibu Gulf in fall than in winter, and the currents off the coast of Vietnam and the northwestern coast of Hainan Island are weaker in fall than those in winter. Most studies indicate that winter boreal circulation is driven by the monsoon wind. The most recent observations and model results suggest that the current in the Qiongzhou Strait (QS) is eastward on certain days in the boreal summer and is affected by the difference between the sea levels of the two ends of the QS and tidal rectification. Correspondingly, the volume transport is approximately -0.1 Sv (minus sign represents

  9. Gulf of Mexico Loop Current path variability

    NASA Astrophysics Data System (ADS)

    Donohue, K. A.; Watts, D. R.; Hamilton, P.; Leben, R.; Kennelly, M.; Lugo-Fernández, A.

    2016-12-01

    Loop Current, LC, path variability exhibits a continuum of spatial and temporal scales, all are called meanders in this work. They arise from a variety of processes, including short and long waves, frontal eddies with or without closed cores and developing baroclinic instability. They have been extensively studied with satellite sea surface temperature SST, and height, SSH. Yet, these systems provide an incomplete view into LC meandering: SST measurements are hampered by cloud coverage and low thermal contrast in summer months and SSH measurements by altimeter temporal and spatial resolution. In an effort to resolve LC meander temporal and spatial scales, they are investigated using a mesoscale resolving in situ array deployed in the Gulf of Mexico. The array, which consisted of twenty-five inverted echo sounders with pressure gauges, PIES, and current meter moorings, was deployed April 2009 and recovered in October-November 2011. The broad extent of the array, nominally 89° W to 85° W, 25° N to 27° N, enabled quantitative mapping of the regional circulation. LC meander properties are characterized as a function of spatial distribution of energy, frequency, wavenumber, and phase speed. Dispersion characteristics and meander scales are comparable to those found in the Gulf Stream. Phase speeds increase with frequency and range from 8 to 50 km d-1. Wavelengths associated with each band are as follows: 460 km for the 100 to 40 d band, 350 km for the 40 to 20 d band, 270 km for the 20 to 10 d band and 230 km for the 10 to 3 d band. The strongest variability is in the 100 to 40 d band. Spatially the 100 to 40 d variability is concentrated to east of the Mississippi Fan, growing and propagating downstream along the eastern portion of the LC. Meanders between 40 and 20 d propagate along the full encompassed length of the LC. Their temporal amplitudes peak at the time of LC eddy detachment and separation. Meanders with shorter periods than 20 d do not always propagate

  10. Ending a Pregnancy

    MedlinePlus

    ... Share Ending a Pregnancy Ending a PregnancyWhat is abortion?Abortion means ending a pregnancy early. In some cases, ... This is called a miscarriage, or a spontaneous abortion. In other cases, a woman chooses to end ...

  11. 75 FR 28760 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Reef Fish Fishery of the Gulf of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-24

    ..., Gulf of Mexico, and South Atlantic; Reef Fish Fishery of the Gulf of Mexico; Amendment 31; Correction... implement Amendment 31 to the Fishery Management Plan for the Reef Fish Resources of the Gulf of Mexico...

  12. The Baselines Project: Establishing Reference Environmental Conditions for Marine Habitats in the Gulf of Mexico using Forecast Models and Satellite Data

    NASA Astrophysics Data System (ADS)

    Jolliff, J. K.; Gould, R. W.; deRada, S.; Teague, W. J.; Wijesekera, H. W.

    2012-12-01

    We provide an overview of the NASA-funded project, "High-Resolution Subsurface Physical and Optical Property Fields in the Gulf of Mexico: Establishing Baselines and Assessment Tools for Resource Managers." Data assimilative models, analysis fields, and multiple satellite data streams were used to construct temperature and photon flux climatologies for the Flower Garden Banks National Marine Sanctuary (FGBNMS) and similar habitats in the northwestern Gulf of Mexico where geologic features provide a platform for unique coral reef ecosystems. Comparison metrics of the products to in situ data collected during complimentary projects are also examined. Similarly, high-resolution satellite-data streams and advanced processing techniques were used to establish baseline suspended sediment load and turbidity conditions in selected northern Gulf of Mexico estuaries. The results demonstrate the feasibility of blending models and data into accessible web-based analysis products for resource managers, policy makers, and the public.

  13. 76 FR 54375 - Safety Zone; Thunder on the Gulf, Gulf of Mexico, Orange Beach, AL

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-01

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Thunder on the Gulf, Gulf of Mexico, Orange... establishing a temporary safety zone for a portion of the Gulf of Mexico for the waters off Orange Beach... Mexico, south of Orange Beach, Alabama to occur from October 6, 2011 through October 9, 2011. This...

  14. Kuwait Oil Fires, Persian Gulf, Qatar Peninsula

    NASA Technical Reports Server (NTRS)

    1991-01-01

    This view up the Persian Gulf from the Qatar Peninsula into southern Iraq (25.5N, 51.0E) shows an excursion of the smoke plumes from the Kuwait oil fires set during the short Persian Gulf War. Smoke from the fires north of Kuwait City, extends across the Persian Gulf while a larger smoke plume from the southern fires heads into southern Saudi Arabia before beginning to spread out and become more diffuse.

  15. Surface sedimentary units of the Gulf of Alaska continental shelf: Montague Island to Yakutat Bay

    USGS Publications Warehouse

    Molnia, Bruce F.

    1977-01-01

    Four major sedimentary units occur on the sea floor of the continental shelf in the northern Gulf of Alaska. These units, defined on the basis of seismic and sedimentologic data, are: (1) Holocene sediments, (2) Holocene mind moraines, C3) Quaternary glacial marine sediments, and (4) Tertiary and Pleistocene lithified deposits. A wedge of Holocene fine sand to clayey silt covers most of the inner shelf, reaching maximum thicknesses of about 350 m seaward of the Copper River and about 200 m seaward of Icy Bay. Holocene end moraines are found at the mouth of Icy Bay, south of Bering Glacier, and at the mouth of Yakutat Bay. Quaternary glacial marine sediments are found in a narrow arc that borders, on the north and west side of Tart Bank and in a large arc 20 km or more offshore that parallels the shoreline between Kayak Island and Yakutat Bay. Tertiary or Pleistocene stratified sedimentary rocks, which in profile commonly are folded, faulted, and truncated, crop out on Tarr Bank, offshore of Montague Island, and in several localities southeast and southwest of Cape Yakataga. The lack of Holocene cover on Tarr Bank and Middleton, Kayak and Montague Island platforms may be due to the scouring action of swift bottom currents and large storm waves. West of Kayak Island the Copper River is the primary source of Holocene sediment. East of Kayak Island the major sediment sources are streams draining the larger ice fields, notably, the Malaspina and Bering Glaciers. Transport of bottom and suspended sediment is predominantly to the west. If deglaciation of the shelf was completed by 10,000 years B.P., maximum rates of accumulation of Holocene sediment on the inner shelf may be as high as 10-35 m per 1,000 years.

  16. Consider an Ice Stream.

    NASA Astrophysics Data System (ADS)

    Bindschadler, R.

    2002-12-01

    Forty years ago, John Nye was one of the leaders who introduced the rigors of classical physics to glaciology. His elegant treatments frequently took advantage of the then recent discovery that ice could be approximated as a plastic material. With this viewpoint, Nye was able to explain the shape of ice sheets and glaciers, to predict the expected pattern of stress and velocity within a glacier, and to derive the advance and retreat of a glacier from the record of accumulation and ablation. These advances have given generations of glaciologists tools to interpret the excellent observational record of glacier behavior and variation. In the 1980s, glaciologist, weaned on these works of Nye and of other similarly adept colleagues, carried their lessons to West Antarctica to study ice streams, the vast conveyor belts of ice that discharged nearly as much Antarctic ice as the much larger East Antarctic ice sheet. Ice streams were a glaciological conundrum. Despite the gently sloping surface, these broad features roared along, moving fastest when the gravitational impetus was least. After two decades of research, ice streams still have not given up all their secrets, yet much is now known. Internal deformation is negligible. Basal friction is frequently nil leaving the shattered margins as the primary means to avoid rapid wastage of the ice sheet. Within the margins, the resistive force results from a delicate balance of heat and evolving ice fabrics. Nevertheless, the bed beneath an ice stream cannot be ignored. It is ultimately the state of the underlying marine sediment that determines whether the ice stream can slide at all. There too, the heat balance is critical with an influx of water required to keep the bed wet enough to let the streams glide along. Ice stream research has been the portal through which glaciologists have seen and identified the complexities of West Antarctic ice sheet dynamics. Remarkably, nearly all time scales seem important. Ice stream

  17. Montana StreamStats

    USGS Publications Warehouse

    2016-04-05

    About this volumeMontana StreamStats is a Web-based geographic information system (http://water.usgs.gov/osw/streamstats/) application that provides users with access to basin and streamflow characteristics for gaged and ungaged streams in Montana. Montana StreamStats was developed by the U.S. Geological Survey (USGS) in cooperation with the Montana Departments of Transportation, Environmental Quality, and Natural Resources and Conservation. The USGS Scientific Investigations Report consists of seven independent but complementary chapters dealing with various aspects of this effort.Chapter A describes the Montana StreamStats application, the basin and streamflow datasets, and provides a brief overview of the streamflow characteristics and regression equations used in the study. Chapters B through E document the datasets, methods, and results of analyses to determine streamflow characteristics, such as peak-flow frequencies, low-flow frequencies, and monthly and annual characteristics, for USGS streamflow-gaging stations in and near Montana. The StreamStats analytical toolsets that allow users to delineate drainage basins and solve regression equations to estimate streamflow characteristics at ungaged sites in Montana are described in Chapters F and G.

  18. Diabatic heating and jet stream shifts: A case study of the 2010 negative North Atlantic Oscillation winter

    NASA Astrophysics Data System (ADS)

    Woollings, Tim; Papritz, Lukas; Mbengue, Cheikh; Spengler, Thomas

    2016-09-01

    The role of extratropical diabatic heating in the variability of storm tracks and jet streams remains an important open question. This paper analyzes the role of diabatic heating in observationally constrained analysis data for the 2010 winter, which was notable for an extreme southward shift of the North Atlantic eddy-driven jet. An isentropic slope framework is employed by which the contribution of diabatic terms to the maintenance of seasonal mean baroclinicity can be quantified. This reveals a striking contrast between the eastern North Atlantic, where the latent heating shifted south along with the storm track in 2010, and the western North Atlantic, where the latent heating remained fixed over the Gulf Stream. This motivates the hypothesis that the latent heating may contribute to the anchoring of the storm track entrance over the Gulf Stream but provide a very different feedback on the jet variability downstream.

  19. Democracy Assistance in the Gulf

    DTIC Science & Technology

    2012-04-01

    4302. Respondents should be aware that notwithstanding any other provision of law , no person shall be subject to any penalty for failing to comply...Assistance in the Gulf 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Colonel Diana M. Holland Colon 5d...democratic community.14 George W. Bush continued his predecessors’ interest in encouraging democracy, and even justified regime change in certain cases

  20. Meandering stream reservoirs

    SciTech Connect

    Richardson, J.G.; Sangree, J.B.; Sneider, R.M.

    1987-12-01

    Braided stream deposits, described in a previous article in this series, and meandering stream deposits commonly are excellent reservoirs. Meandering high-sinuousity channels are found on flat alluvial plains with slopes less than 1 1/2/sup 0/ (0.026 rad). These rivers have wide ranges of discharges from low-water flow to flood stage. Two main processes are responsible for development of sand bodies. These are point-bar deposits left by channel migration, and oxbow-lake deposits left in loops of the river course abandoned when the stream cuts a new course during flooding. Extremely high floods spill over the banks and deposit sheets of very fine sand, silt, and clay onto the flood plain.

  1. Slow adaptation in the face of rapid warming leads to collapse of the Gulf of Maine cod fishery.

    PubMed

    Pershing, Andrew J; Alexander, Michael A; Hernandez, Christina M; Kerr, Lisa A; Le Bris, Arnault; Mills, Katherine E; Nye, Janet A; Record, Nicholas R; Scannell, Hillary A; Scott, James D; Sherwood, Graham D; Thomas, Andrew C

    2015-11-13

    Several studies have documented fish populations changing in response to long-term warming. Over the past decade, sea surface temperatures in the Gulf of Maine increased faster than 99% of the global ocean. The warming, which was related to a northward shift in the Gulf Stream and to changes in the Atlantic Multidecadal Oscillation and Pacific Decadal Oscillation, led to reduced recruitment and increased mortality in the region's Atlantic cod (Gadus morhua) stock. Failure to recognize the impact of warming on cod contributed to overfishing. Recovery of this fishery depends on sound management, but the size of the stock depends on future temperature conditions. The experience in the Gulf of Maine highlights the need to incorporate environmental factors into resource management.

  2. Seasonal variations of Shamal wind in the Arabian Gulf

    NASA Astrophysics Data System (ADS)

    Saleh Almehrezi, Ali Saif Ali; Shapiro, Georgy; Thain, Richard; Priestley, Duncan

    2013-04-01

    The purpose of this paper is to present the results of a study into seasonal Shamal wind variations in the southern Arabian Gulf. The literature on the subject is reviewed; and the site of the study is discussed from the aspects of weather and wind cycles. Collected wind data, over a thirty year period (1981 to 2010), from Bahrain, Abu Dhabi, Sharjah and NCEP is analyzed and clearly indicates that the Shamal wind is a major feature within the region. Furthermore, over this thirty year period, analysis and observations show that there has been a reduction in Shamal wind force. Due to a number of factors, but primarily its location, wind data from Bahrain is a key element of this study analysis in order to show variations in Shamal wind strength over the southern of the Arabian Gulf. The synoptic conditions which help to understand the wind cycles are analyzed in order to establish a fundamental level of environmental information. A key finding is that the winter Shamal wind in the lower atmosphere is clearly associated with an upper air trough; therefore, the location of the Middle East jet stream has an effect on Shamal wind duration. Furthermore, this finding would suggest that the Arctic oscillation has an indirect effect on the Shamal wind. Additionally, the location and strength of the surface Azores High system has an influence on the Arabian Peninsula High which subsequently affects Shamal wind strength.

  3. Gasification of Gulf Coast Lignites

    SciTech Connect

    Smoller, R.K.

    1983-11-01

    Gulf Coast lignites are examined as a feedstock for a gasification facility making substitute natural gas (SNG). Advantages and disadvantages are explored in the areas of project development factors, gasification technology and physical and chemical characteristics of the lignite. The Texas Gasification Project currently under study at Phillips Coal is used to exemplify these factors. It has been found that the use of Gulf Coast lignite has several natural developmental advantages over fuels from other parts of the U.S. A project is relatively close to markets for all of its products including SNG, carbon dioxide and all by-products. The Gulf Coast has adequate supplies of basic commodities such as water. Most potential gasification plant locations have a good local infrastructure in existence. Labor can be drawn from one or more metropolitan areas within commuting distance. State regulatory agencies interact with energy development projects of all sizes on a regular basis providing a solid working knowledge of energy policies and accepted project development guidelines. Finally, a positive business climate exists at both the state and local levels providing support and encouragement to go forward with projects. The physical and chemical characteristics of the lignite are shown to have a major effect on the operability of the gasification process. Lignite properties examined include moisture content, friability, and ash content.

  4. Migration of induced-infiltrated stream water into nearby aquifers due to seasonal ground water withdrawal.

    PubMed

    Chen, X

    2001-01-01

    Analysis of stream-aquifer interaction due to ground water extraction has traditionally focused on the determination of the amount of water depleted in the stream. Less attention has been paid to the movement of infiltrated stream water inside aquifer, particularly for agricultural areas. This paper presents a method of using particle-tracking techniques to evaluate the transport of the leaked stream water in the nearby aquifers. Simple stream-aquifer conditions are used to demonstrate the usefulness of the analysis. Travel times, pathlines, and influence zones of stream water were determined between a stream and nearby pumping wells for seasonal ground water extraction areas. When water quantity is a concern, the analyses provide additional information about stream depletion; when water quality is an issue, they offer information for wellhead protection. Analyses were conducted for transient conditions, and both pumping and nonpumping periods were considered. According to the results from the simulation examples, migration of infiltrated stream water into the nearby aquifers is generally slow and most infiltrated stream water does not arrive at the pumping well at the end of a 90-day irrigation season. Infiltrated stream water may remain in the aquifer for several years before arriving at the pumping well. For aquifers with a regional hydraulic gradient toward streams, part of the infiltrated stream water may discharge back to streams during a recovery period.

  5. Occurrence and amount of microplastic ingested by fishes in watersheds of the Gulf of Mexico.

    PubMed

    Phillips, Melissa B; Bonner, Timothy H

    2015-11-15

    Ingestion of microplastics by fishes could be an emerging environmental crisis because of the proliferation of plastic pollution in aquatic environments. Microplastics in marine ecosystems are well documented, however only one study has reported percent occurrence of microplastics in freshwater fishes. The purpose of this study was to quantify the occurrences and types of microplastics ingested by fishes within several freshwater drainages of the Gulf of Mexico and an estuary of the Gulf of Mexico. Among 535 fishes examined in this study, 8% of the freshwater fishes and 10% of the marine fishes had microplastics in their gut tract. Percentage occurrence of microplastics ingested by fishes in non-urbanized streams (5%) was less than that of one of the urbanized streams (Neches River; 29%). Percent occurrence of microplastics by habitat (i.e., benthic, pelagic) and trophic guilds (herbivore/omnivore, invertivore, carnivore) were similar. Low but widespread occurrences among drainages, habitat guilds, and trophic guilds indicate proliferation of plastic pollution within watersheds of the Gulf of Mexico, but consequences to fish health are unknown at this time.

  6. Antibodies to squalene in US Navy Persian Gulf War veterans with chronic multisymptom illness.

    PubMed

    Phillips, Christopher J; Matyas, Gary R; Hansen, Christian J; Alving, Carl R; Smith, Tyler C; Ryan, Margaret A K

    2009-06-12

    Since the end of the 1991 Gulf War, there have been reports of unexplained, multisymptom illnesses afflicting veterans who consistently report more symptoms than do nondeployed veterans. One of the many possible exposures suspected of causing chronic multisymptom illnesses Gulf War veterans is squalene, thought to be present in anthrax vaccine. We examined the relationship between squalene antibodies and chronic symptoms reported by Navy construction workers (Seabees), n=579. 30.2% were deployers, 7.4% were defined as ill, and 43.5% were positive for squalene antibodies. We found no association between squalene antibody status and chronic multisymptom illness (p=0.465). The etiology of Gulf War syndrome remains unknown, but should not include squalene antibody status.

  7. The Role of Tigris Euphrates Discharge on Coastal SST in the Arabian Gulf

    NASA Astrophysics Data System (ADS)

    Becker, R.; Sanders, J.

    2013-12-01

    The Tigris-Euphrates (T-E) river system provides most of the freshwater recharge into the Arabian/Persian Gulf, through the Shatt el-Arab, into the northern Gulf. Over the past decades, increased dam storage for irrigation and hydropower throughout the region has modified the characteristics of this flow. As a result, flow into the Iraqi Marshes has been reduced by at least half, with reduction in both peak and overall flow, and a corresponding decrease in flow through the Shatt el-Arab. This change in flow characteristics is observable in the waters on the Northern Gulf and in Kuwait bay. AVHRR Pathfinder v5.0 8 day data was assembled for the time period 1985-2010. Time series were extracted for sea surface temperature (SST) for locations in the Northern and Central Gulf and Kuwait Bay. These were compared with regional precipitation and GRACE water equivalent thickness variations in the upper and lower T-E basin, and published flow estimates. Results were used to examine 1) the overall impact of discharge on SST in the coastal area affected by T-E watershed discharge; 2) the impact of reduced flow years due to damming and drought years on the differences between coastal and bay SST and central Gulf SST. Annual peak flow in the period Dec-April was found to provide a lowering of coastal SST by more than 1C compared with more well mixed water in the central Gulf. This effect was not seen to be less than half during drought years (e.g. 2006-2008). Climate models predict end of century scenarios of precipitation similar to those seen during 2007-2008. The impact of this lower discharge from the Shatt el-Arab combined with predicted regional warming may result in habitat changes in coastal waters in the Northern Gulf.

  8. Identifying hidden voice and video streams

    NASA Astrophysics Data System (ADS)

    Fan, Jieyan; Wu, Dapeng; Nucci, Antonio; Keralapura, Ram; Gao, Lixin

    2009-04-01

    Given the rising popularity of voice and video services over the Internet, accurately identifying voice and video traffic that traverse their networks has become a critical task for Internet service providers (ISPs). As the number of proprietary applications that deliver voice and video services to end users increases over time, the search for the one methodology that can accurately detect such services while being application independent still remains open. This problem becomes even more complicated when voice and video service providers like Skype, Microsoft, and Google bundle their voice and video services with other services like file transfer and chat. For example, a bundled Skype session can contain both voice stream and file transfer stream in the same layer-3/layer-4 flow. In this context, traditional techniques to identify voice and video streams do not work. In this paper, we propose a novel self-learning classifier, called VVS-I , that detects the presence of voice and video streams in flows with minimum manual intervention. Our classifier works in two phases: training phase and detection phase. In the training phase, VVS-I first extracts the relevant features, and subsequently constructs a fingerprint of a flow using the power spectral density (PSD) analysis. In the detection phase, it compares the fingerprint of a flow to the existing fingerprints learned during the training phase, and subsequently classifies the flow. Our classifier is not only capable of detecting voice and video streams that are hidden in different flows, but is also capable of detecting different applications (like Skype, MSN, etc.) that generate these voice/video streams. We show that our classifier can achieve close to 100% detection rate while keeping the false positive rate to less that 1%.

  9. Practical Meteor Stream Forecasting

    NASA Technical Reports Server (NTRS)

    Cooke, William J.; Suggs, Robert M.

    2003-01-01

    Inspired by the recent Leonid meteor storms, researchers have made great strides in our ability to predict enhanced meteor activity. However, the necessary calibration of the meteor stream models with Earth-based ZHRs (Zenith Hourly Rates) has placed emphasis on the terran observer and meteor activity predictions are published in such a manner to reflect this emphasis. As a consequence, many predictions are often unusable by the satellite community, which has the most at stake and the greatest interest in meteor forecasting. This paper suggests that stream modelers need to pay more attention to the needs of this community and publish not just durations and times of maxima for Earth, but everything needed to characterize the meteor stream in and out of the plane of the ecliptic, which, at a minimum, consists of the location of maximum stream density (ZHR) and the functional form of the density decay with distance from this point. It is also suggested that some of the terminology associated with meteor showers may need to be more strictly defined in order to eliminate the perception of crying wolf by meteor scientists. An outburst is especially problematic, as it usually denotes an enhancement by a factor of 2 or more to researchers, but conveys the notion of a sky filled with meteors to satellite operators and the public. Experience has also taught that predicted ZHRs often lead to public disappointment, as these values vastly overestimate what is seen.

  10. Toward Third Stream Evaluation.

    ERIC Educational Resources Information Center

    Della-Piana, Gabriel M.; Endo, George T.

    Third stream evaluation, the fusing of the ecological perspective with experimental or quasi-experimental evaluation design, is described. The ecological perspective necessitates that the conceptualization and analysis of a setting and the design of the study emphasize the interdependent relations among organisms, behavior and environment in…

  11. 78 FR 22949 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-17

    ...NMFS hereby reorganizes the regulations implementing the fishery management plans (FMPs) for the following domestic fisheries in the Caribbean, Gulf of Mexico, and South Atlantic: Caribbean coral, Caribbean reef fish, Caribbean spiny lobster, Caribbean queen conch, Gulf red drum, Gulf reef fish, Gulf shrimp, Gulf coral, Gulf and South Atlantic coastal migratory pelagics, Gulf and South......

  12. Explaining the "Pulse of Protoplasm": the search for molecular mechanisms of protoplasmic streaming.

    PubMed

    Dietrich, Michael R

    2015-01-01

    Explanations for protoplasmic streaming began with appeals to contraction in the eighteenth century and ended with appeals to contraction in the twentieth. During the intervening years, biologists proposed a diverse array of mechanisms for streaming motions. This paper focuses on the re-emergence of contraction among the molecular mechanisms proposed for protoplasmic streaming during the twentieth century. The revival of contraction is a result of a broader transition from colloidal chemistry to a macromolecular approach to the chemistry of proteins, the recognition of the phenomena of shuttle streaming and the pulse of protoplasm, and the influential analogy between protoplasmic streaming and muscle contraction.

  13. Probiotic (VSL#3) for Gulf War Illness

    DTIC Science & Technology

    2014-10-01

    efforts are ongoing to recruit more Gulf War veterans. The first set of stool samples have been sent to Lawrence Berkeley Laboratory microbiota analysis...the Lawrence Berkeley laboratory for microbiota analysis.  We have received the list of Gulf War Veterans in the Salt Lake City are from the Defense

  14. GULF OF MEXICO AQUATIC MORTALITY NETWORK (GMNET)

    EPA Science Inventory

    Five U.S. states share the northern coast of the Gulf, and each has a program to monitor mortalities of aquatic organisms (fish, shellfish, birds). However, each state has different standards, procedures, and documentation of mortality events. The Gulf of Mexico Aquatic Mortality...

  15. Gulf Coast Community College's Memory Project

    ERIC Educational Resources Information Center

    Burrell, Matthew D.

    2005-01-01

    Gulf Coast Community College in Panama City, Florida, is celebrating a fifty-year anniversary in 2007. Maintained by the library, the school's archives represent the historical contributions on a local and national level. Gulf Coast Community College library is ensuring the school's historical significance through the digitization of its…

  16. OCEANOGRAPHY IN THE GULF OF MEXICO.

    DTIC Science & Technology

    The report gives a summary of oceanographic research in the Gulf of Mexico supported by the Office of Naval Research during the period 1 May 1961...15 December 1969. This research involved theoretical studies in ocean dynamics; currents in the Gulf of Mexico , Cayman Sea, western tropical Atlantic

  17. Gulf of Mexico Ocean Monitoring System

    DTIC Science & Technology

    1998-01-01

    between our own participants within the Ocean Monitoring System (OMS) Program and also with other research efforts in the Gulf of Mexico whose...prepare the most complete possible analysis and summary of the prevailing oceanographic conditions in the Gulf of Mexico and make it available to

  18. Improving Education in the Arabian Gulf Region.

    ERIC Educational Resources Information Center

    Rasheed, Mohammed A.; Hengst, Herbert R.

    1983-01-01

    Educational development in the seven Arab states of the Gulf region has been stimulated by the Arab Bureau of Education for the Gulf States (ABEGS), established in 1976. ABEGS has focused on obtaining information on education programs from member states, educating Arabs about their own culture, and establishing a multinational university. (LC)

  19. D region depletions above the Persian Gulf

    NASA Astrophysics Data System (ADS)

    Givishvili, G. V.; Leshchenko, L. N.

    1993-01-01

    The extraordinary delay of the daily variation of absorption and electron density observed in the ionospheric D region above the Persian Gulf in 1976 observed from the research vessel 'Akademik Kurchatov' may be a consequence of air pollution by oil production by-products. It is suggested that the Gulf war might also have caused a lower ozone abundance in that region.

  20. Wireless network interface energy consumption implications of popular streaming formats

    NASA Astrophysics Data System (ADS)

    Chandra, Surendar

    2001-12-01

    With the proliferation of mobile streaming multimedia, available battery capacity constrains the end-user experience. Since streaming applications tend to be long running, wireless network interface card's (WNIC) energy consumption is particularly an acute problem. In this work, we explore the WNIC energy consumption implications of popular multimedia streaming formats from Microsoft (Windows media), Real (Real media) and Apple (Quick Time). We investigate the energy consumption under varying stream bandwidth and network loss rates. We also explore history-based client-side strategies to reduce the energy consumed by transitioning the WNICs to a lower power consuming sleep state. We show that Microsoft media tends to transmit packets at regular intervals; streams optimized for 28.8 Kbps can save over 80% in energy consumption with 2% data loss. A high bandwidth stream (768 Kbps) can still save 57% in energy consumption with less than 0.3% data loss. For high bandwidth streams, Microsoft media exploits network-level packet fragmentation, which can lead to excessive packet loss (and wasted energy) in a lossy network. Real stream packets tend to be sent closer to each other, especially at higher bandwidths. Quicktime packets sometimes arrive in quick succession; most likely an application level fragmentation mechanism. Such packets are harder to predict at the network level without understanding the packet semantics.

  1. Labor, nationalism, and imperialism in eastern Arabia: Britain, the Shaikhs, and the Gulf oil workers in Bahrain, Kuwait and Qatar, 1932-1956

    SciTech Connect

    Saleh, H.M.A.

    1991-01-01

    This study examines the lack of a noticeable indigenous labor movement in the contemporary Gulf Arab countries of Bahrain, Kuwait and Qatar; it focuses on the emergence, after the discovery of oil, of an industrial Gulf labor force, and on the evolution of the British policy towards oil and Gulf oil workers. The period examined begins with the discovery of oil in Bahrain in 1932 (the first such discovery on the Arab side of the Gulf), and ends with the Suez Crisis of 1956. The latter is a watershed event in Gulf history. It is argued that the Suez Crisis was in large part responsible for the long-term defeat of the indigenous labor movement in the Gulf. Attention is given to the parts played by the British Government of India, the Foreign Office, the local Shaikhs, the Gulf nationalists, and by the workers themselves. Policies towards workers passed through two different periods. In the first, 1932-1945, the Government of India had no direct interest in the Gulf labor situation; in the second, 1946-1956, the Foreign Office took increased interest in the welfare of local oil workers, primarily because of the importance of oil to reconstruction of the British economy after the war. However, the Suez Crisis in 1956 convinced the British to withdraw their support for the workers.

  2. ASSESSING HEADWATER STREAMS: LINKING LANDSCAPES TO STREAM NETWORKS

    EPA Science Inventory

    Headwater streams represent a significant land-water boundary and drain 70-80% of the landscape. Headwater streams are vital components to drainage systems and are directly linked to our downstream rivers and lakes. However, alteration and loss of headwater streams have occurre...

  3. A Simulated Stream Ecology Study.

    ERIC Educational Resources Information Center

    Zampella, Robert A.

    1979-01-01

    Describes a simulated field experience to study stream ecology in the classroom. Secondary students determine the composition of the stream community, describe the distribution of the benthic invertebrates, and design a food web. (Author/MA)

  4. 75 FR 16577 - Gulf War Veterans' Illnesses Task Force

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-01

    ... AFFAIRS Gulf War Veterans' Illnesses Task Force AGENCY: Department of Veterans Affairs (VA). ACTION... the Gulf War Veterans' Illnesses Task Force (GWVI-TF) in August 2009 to conduct a comprehensive review of VA's approach to and programs addressing 1990-1991 Gulf War Veterans' illnesses. The Gulf...

  5. Gulf war depleted uranium risks.

    PubMed

    Marshall, Albert C

    2008-01-01

    US and British forces used depleted uranium (DU) in armor-piercing rounds to disable enemy tanks during the Gulf and Balkan Wars. Uranium particulate is generated by DU shell impact and particulate entrained in air may be inhaled or ingested by troops and nearby civilian populations. As uranium is slightly radioactive and chemically toxic, a number of critics have asserted that DU exposure has resulted in a variety of adverse health effects for exposed veterans and nearby civilian populations. The study described in this paper used mathematical modeling to estimate health risks from exposure to DU during the 1991 Gulf War for both US troops and nearby Iraqi civilians. The analysis found that the risks of DU-induced leukemia or birth defects are far too small to result in an observable increase in these health effects among exposed veterans or Iraqi civilians. The analysis indicated that only a few ( approximately 5) US veterans in vehicles accidentally targeted by US tanks received significant exposure levels, resulting in about a 1.4% lifetime risk of DU radiation-induced fatal cancer (compared with about a 24% risk of a fatal cancer from all other causes). These veterans may have also experienced temporary kidney damage. Iraqi children playing for 500 h in DU-destroyed vehicles are predicted to incur a cancer risk of about 0.4%. In vitro and animal tests suggest the possibility of chemically induced health effects from DU internalization, such as immune system impairment. Further study is needed to determine the applicability of these findings for Gulf War exposure to DU. Veterans and civilians who did not occupy DU-contaminated vehicles are unlikely to have internalized quantities of DU significantly in excess of normal internalization of natural uranium from the environment.

  6. Apparatus for removing a contaminant from a fluid stream

    DOEpatents

    Brewster, M.D.; Posa, R.P.

    1998-12-22

    A device for removing a contaminant from a fluid stream flowing within a conduit is disclosed. The device includes a container and a barrier. The container has a first wall generated about an axis and a second wall generated about the same axis. The first wall defines a first volume therewithin, while the first and second walls define an annular second volume therebetween. Both the first and second volumes are sealed at one end of the device, while at the other end of the device the second volume only is sealed. A filter material occupies the second volume. The first and second walls are permeable to the fluid stream and are capable of retaining the filter material in the second volume. The barrier is impermeable to the fluid stream and creates a seal between the second wall and the conduit wall. The barrier is positioned adjacent the other end of the device such that when the other end of the device is the upstream end, the fluid stream must sequentially pass into the first volume, through the first wall, into the second volume and through the filter material, and through the second wall. 4 figs.

  7. Apparatus for removing a contaminant from a fluid stream

    DOEpatents

    Brewster, Michael D.; Posa, Richard P.

    1998-01-01

    A device for removing a contaminant from a fluid stream flowing within a conduit is disclosed. The device includes a container and a barrier. The container has a first wall generated about an axis and a second wall generated about the same axis. The first wall defines a first volume therewithin, while the first and second walls define an annular second volume therebetween. Both the first and second volumes are sealed at one end of the device, while at the other end of the device the second volume only is sealed. A filter material occupies the second volume. The first and second walls are permeable to the fluid stream and are capable of retaining the filter material in the second volume. The barrier is impermeable to the fluid stream and creates a seal between the second wall and the conduit wall. The barrier is positioned adjacent the other end of the device such that when the other end of the device is the upstream end, the fluid stream must sequentially pass into the first volume, through the first wall, into the second volume and through the filter material, and through the second wall.

  8. Don't Cross the (Tidal) Streams

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2015-09-01

    In a tidal disruption event (TDE), an unfortunate star passes too close to a dormant supermassive black hole (BH) and gets torn apart by tidal forces, feeding the BH for a short time. Oddly, were not finding nearly as many TDEs typically detected due to their distinctive observational signatures as theory says we should. A recent study suggests that we might be missing many of these events, due to the way the streams of shredded stars fall onto the BHs.Signatures of ShreddingWhen a BH tears a star apart, the stars material is stretched out into whats known as a tidal stream. That stream continues on a trajectory around the BH, with roughly half the material eventually falling back on the BH, whipping around it in a series of orbits. Where those orbits intersect each other, the material smashes together and circularizes, forming a disk that then accretes onto the BH.What does a TDE look like? We dont observe anything until after the tidal streams collide and the material begins to accrete onto the BH. At that point we observe a sudden peak in luminosity, which then gradually decreases (scaling roughly as time-5/3) as the tail end of whats left of the star accretes and the BHs food source eventually runs out.So why have we only been observing about a tenth as many TDEs as theory predicts we should see? By studying the structure of tidal streams in TDEs, James Guillochon (Harvard-Smithsonian Center for Astrophysics) and Enrico Ramirez-Ruiz (UC Santa Cruz) have found a potential reason and the culprit is general relativity.Dark YearsThe authors run a series of simulations of TDEs around black holes of varying masses and spins to see what form the resulting tidal streams take over time. They find that precession of the tidal stream due to the BHs gravitational effects changes how the stream interacts with itself, and therefore what we observe. Some cases behave like what we expect for whats currently considered a typical TDE but some dont.Example from simulations of a

  9. Digital Multicasting of Multiple Audio Streams

    NASA Technical Reports Server (NTRS)

    Macha, Mitchell; Bullock, John

    2007-01-01

    The Mission Control Center Voice Over Internet Protocol (MCC VOIP) system (see figure) comprises hardware and software that effect simultaneous, nearly real-time transmission of as many as 14 different audio streams to authorized listeners via the MCC intranet and/or the Internet. The original version of the MCC VOIP system was conceived to enable flight-support personnel located in offices outside a spacecraft mission control center to monitor audio loops within the mission control center. Different versions of the MCC VOIP system could be used for a variety of public and commercial purposes - for example, to enable members of the general public to monitor one or more NASA audio streams through their home computers, to enable air-traffic supervisors to monitor communication between airline pilots and air-traffic controllers in training, and to monitor conferences among brokers in a stock exchange. At the transmitting end, the audio-distribution process begins with feeding the audio signals to analog-to-digital converters. The resulting digital streams are sent through the MCC intranet, using a user datagram protocol (UDP), to a server that converts them to encrypted data packets. The encrypted data packets are then routed to the personal computers of authorized users by use of multicasting techniques. The total data-processing load on the portion of the system upstream of and including the encryption server is the total load imposed by all of the audio streams being encoded, regardless of the number of the listeners or the number of streams being monitored concurrently by the listeners. The personal computer of a user authorized to listen is equipped with special- purpose MCC audio-player software. When the user launches the program, the user is prompted to provide identification and a password. In one of two access- control provisions, the program is hard-coded to validate the user s identity and password against a list maintained on a domain-controller computer

  10. Gulf Cooperation Council: search for security in the Persian Gulf

    SciTech Connect

    Kechichian, J.A.

    1985-01-01

    This study purports to analyze the conservative Arab monarchies' search for regional security in the Persian Gulf. It speculates on the GCC's future prospects as a vehicle of cooperation in the field of security. Threats to the member states of the GCC stem from the policies pursued by revolutionary Iran, Israel, the Soviet Union and its proxies, and a regime in Iraq. The proposition is developed that these sources of threat present an overwhelming challenge to the security and stability of GCC states. Second, it examines the capabilities of the GCC member states for coping with threats. Conceived broadly, both military and non-military capabilities are examined. Security relations of the GCC states with external powers as a means of enhancing their abilities to cope more effectively with both internal and external threats are examined. Particular attention is devoted to the domestic consequences of these special relations. Third, it discusses the GCC's reactions to perceived regional threats. These include the Iran-Iraq War, the Arab-Israeli conflict, the Soviet threat, and potential political sources of dissidence in member states. It is argued that although GCC states have adopted a number of joint policies, they did not respond to or initiate action on either the Iranian Revolution, the Palestine conflict, the Soviet occupation of Afghanistan, the Gulf war or the recent Israeli invasion of Lebanon.

  11. 78 FR 49440 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Reef Fish Fishery of the Gulf of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-14

    ...NMFS proposes to implement management measures described in a framework action to the Fishery Management Plan for the Reef Fish Resources of the Gulf of Mexico (FMP), as prepared by the Gulf of Mexico Fishery Management Council (Council). If implemented, this rule would increase the 2013 commercial and recreational quotas for red snapper in the Gulf of Mexico (Gulf) reef fish fishery and......

  12. 77 FR 31734 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Reef Fish Fishery of the Gulf of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-30

    ..., Gulf of Mexico, and South Atlantic; Reef Fish Fishery of the Gulf of Mexico; Red Snapper Management... rule increases the commercial and recreational quotas for red snapper in the Gulf of Mexico (Gulf) reef... final rule is intended to provide more flexibility in managing recreational red snapper and to...

  13. 78 FR 46292 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Reef Fish Fishery of the Gulf of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-31

    ..., Gulf of Mexico, and South Atlantic; Reef Fish Fishery of the Gulf of Mexico; Coastal Migratory Pelagic Resources of the Gulf of Mexico and South Atlantic; Abbreviated Framework AGENCY: National Marine Fisheries... framework to the Fishery Management Plans (FMPs) for the Reef Fish Resources of the Gulf of Mexico...

  14. 78 FR 34586 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Reef Fish Fishery of the Gulf of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-10

    ... the recreational sector for red snapper in the EEZ off individual Gulf states. Therefore, NMFS adjusts..., instead of closing the EEZ on different days off individual Gulf states. This Gulf-wide EEZ closure is... across all Gulf states. Taking into account the catches expected later in 2013 during the extended...

  15. Tropical small streams are a consistent source of methane

    NASA Astrophysics Data System (ADS)

    Vihermaa, Leena; Waldron, Susan

    2013-04-01

    To date only a few studies have quantified diffusive methane emissions from headwater streams therefore the magnitude and seasonal variation of these emissions remain poorly understood. Here we present results from two Western Amazonian small streams (first and second order) in Tambopata National Reserve, Peru. Towards the end of wet season, April-May 2012, the streams were sampled using a static floating chamber to accumulate methane. Samples were drawn from the headspace twice daily over period of four days on three separate occasions. The methane concentrations were analysed using a gas chromatograph and the linear part of concentration increase used to calculate the flux rates. The streams were consistently outgassing methane. The seasonally active first order stream outgassed 6 ±2.4 nmol CH4-C m-2 s-1 and the second order stream 20 ±4.0 nmol CH4-C m-2 s-1. The latter flux rate is comparable to fluxes measured from seasonally flooded Amazonian forest in previous studies. The range measured in our streams is comparable to previous results in temperate streams and the lower end of fluxes observed in some peatland streams. The only other study on Amazonian small streams detected methane fluxes that were 100 times greater than those measured here. Depending on the density of small streams in Amazonian basin and the prevalent flux rate, the fluvial methane fluxes may constitute a significant global warming potential. Upscaling to the Amazon basin, assuming small stream density of 0.2 %, as was found at our field site, and the flux rates detected, yields an annual global warming potential equal to approximately 1.5 Mt of CO2 which is of minor importance compared to aquatic CO2-C flux of 500 Mt yr-1 from the basin. However, if the higher fluxes detected in the previous study were prevalent, the basin wide methane flux could become significant. Further studies are needed to establish the stream density in the Amazon basin and typical methane flux rates.

  16. Stream Channel Stability.

    DTIC Science & Technology

    1981-04-01

    geometry of the stilling basin and appurtenances for optimum energy dissipation. The hydraulic design, based on a 100-year return period design storm...cases the only viable alternative based on present technology is to let the channel seek its oa equilibrium, but attempt to minimize total losses by...are degrading, resulting in bank caving, land loss , and damage to highway bridges. Many streams have enlarged to the extent that 50 to 100-year runoff

  17. Autonomous Byte Stream Randomizer

    NASA Technical Reports Server (NTRS)

    Paloulian, George K.; Woo, Simon S.; Chow, Edward T.

    2013-01-01

    Net-centric networking environments are often faced with limited resources and must utilize bandwidth as efficiently as possible. In networking environments that span wide areas, the data transmission has to be efficient without any redundant or exuberant metadata. The Autonomous Byte Stream Randomizer software provides an extra level of security on top of existing data encryption methods. Randomizing the data s byte stream adds an extra layer to existing data protection methods, thus making it harder for an attacker to decrypt protected data. Based on a generated crypto-graphically secure random seed, a random sequence of numbers is used to intelligently and efficiently swap the organization of bytes in data using the unbiased and memory-efficient in-place Fisher-Yates shuffle method. Swapping bytes and reorganizing the crucial structure of the byte data renders the data file unreadable and leaves the data in a deconstructed state. This deconstruction adds an extra level of security requiring the byte stream to be reconstructed with the random seed in order to be readable. Once the data byte stream has been randomized, the software enables the data to be distributed to N nodes in an environment. Each piece of the data in randomized and distributed form is a separate entity unreadable on its own right, but when combined with all N pieces, is able to be reconstructed back to one. Reconstruction requires possession of the key used for randomizing the bytes, leading to the generation of the same cryptographically secure random sequence of numbers used to randomize the data. This software is a cornerstone capability possessing the ability to generate the same cryptographically secure sequence on different machines and time intervals, thus allowing this software to be used more heavily in net-centric environments where data transfer bandwidth is limited.

  18. Gas stream cleanup

    SciTech Connect

    Bossart, S.J.; Cicero, D.C.; Zeh, C.M.; Bedick, R.C.

    1990-08-01

    This report describes the current status and recent accomplishments of gas stream cleanup (GSCU) projects sponsored by the Morgantown Energy Technology Center (METC) of the US Department of Energy (DOE). The primary goal of the Gas Stream Cleanup Program is to develop contaminant control strategies that meet environmental regulations and protect equipment in advanced coal conversion systems. Contaminant control systems are being developed for integration into seven advanced coal conversion processes: Pressurized fludized-bed combustion (PFBC), Direct coal-fueled turbine (DCFT), Intergrated gasification combined-cycle (IGCC), Gasification/molten carbonate fuel cell (MCFC), Gasification/solid oxide fuel cell (SOFC), Coal-fueled diesel (CFD), and Mild gasification (MG). These advanced coal conversion systems present a significant challenge for development of contaminant control systems because they generate multi-contaminant gas streams at high-pressures and high temperatures. Each of the seven advanced coal conversion systems incorporates distinct contaminant control strategies because each has different contaminant tolerance limits and operating conditions. 59 refs., 17 figs., 5 tabs.

  19. The LHCb Turbo stream

    NASA Astrophysics Data System (ADS)

    Puig, A.

    2016-07-01

    The LHCb experiment will record an unprecedented dataset of beauty and charm hadron decays during Run II of the LHC, set to take place between 2015 and 2018. A key computing challenge is to store and process this data, which limits the maximum output rate of the LHCb trigger. So far, LHCb has written out a few kHz of events containing the full raw sub-detector data, which are passed through a full offline event reconstruction before being considered for physics analysis. Charm physics in particular is limited by trigger output rate constraints. A new streaming strategy includes the possibility to perform the physics analysis with candidates reconstructed in the trigger, thus bypassing the offline reconstruction. In the Turbo stream the trigger will write out a compact summary of physics objects containing all information necessary for analyses. This will allow an increased output rate and thus higher average efficiencies and smaller selection biases. This idea will be commissioned and developed during 2015 with a selection of physics analyses. It is anticipated that the turbo stream will be adopted by an increasing number of analyses during the remainder of LHC Run II (2015-2018) and ultimately in Run III (starting in 2020) with the upgraded LHCb detector.

  20. Stream processing health card application.

    PubMed

    Polat, Seda; Gündem, Taflan Imre

    2012-10-01

    In this paper, we propose a data stream management system embedded to a smart card for handling and storing user specific summaries of streaming data coming from medical sensor measurements and/or other medical measurements. The data stream management system that we propose for a health card can handle the stream data rates of commonly known medical devices and sensors. It incorporates a type of context awareness feature that acts according to user specific information. The proposed system is cheap and provides security for private data by enhancing the capabilities of smart health cards. The stream data management system is tested on a real smart card using both synthetic and real data.

  1. Gulf War illness: a view from Australia

    PubMed Central

    Sim, Malcolm; Kelsall, Helen

    2006-01-01

    Australia sent a small, mostly naval, deployment to the 1991 Gulf War. When papers and media concerns arose about unexplained Gulf War illnesses in Gulf War troops from other countries, Australia decided to undertake its own study of Australian veterans. Undertaking a later study, more than 10 years after the Gulf War, allowed us to incorporate some methodological improvements on previous research, such as the inclusion of a face-to-face health assessment where more objective health data could be collected in addition to using a postal questionnaire. Despite the different Gulf War experience for the mostly naval Australian group, there were remarkable consistencies in the patterns of multiple symptom reporting found in overseas studies, including the fact that no unique symptom clusters were identified. In general, this excess symptom reporting was not found to occur with excesses in more objective measures of physical health. These objective physical measures included a wide range of haematological, biochemical and serological markers, a physical examination, spirometry and a step test of fatigability. In contrast, several psychological disorders, including anxiety, post-traumatic stress disorder, depression and substance abuse, were found to occur in excess in the Australian Gulf War group and were associated with Gulf War psychological stressors. These findings have helped raise awareness in Australia of psychological health problems in deployed military personnel. PMID:16687266

  2. Decision making and ambiguity in auditory stream segregation.

    PubMed

    Deike, Susann; Heil, Peter; Böckmann-Barthel, Martin; Brechmann, André

    2015-01-01

    Researchers of auditory stream segregation have largely taken a bottom-up view on the link between physical stimulus parameters and the perceptual organization of sequences of ABAB sounds. However, in the majority of studies, researchers have relied on the reported decisions of the subjects regarding which of the predefined percepts (e.g., one stream or two streams) predominated when subjects listened to more or less ambiguous streaming sequences. When searching for neural mechanisms of stream segregation, it should be kept in mind that such decision processes may contribute to brain activation, as also suggested by recent human imaging data. The present study proposes that the uncertainty of a subject in making a decision about the perceptual organization of ambiguous streaming sequences may be reflected in the time required to make an initial decision. To this end, subjects had to decide on their current percept while listening to ABAB auditory streaming sequences. Each sequence had a duration of 30 s and was composed of A and B harmonic tone complexes differing in fundamental frequency (ΔF). Sequences with seven different ΔF were tested. We found that the initial decision time varied non-monotonically with ΔF and that it was significantly correlated with the degree of perceptual ambiguity defined from the proportions of time the subjects reported a one-stream or a two-stream percept subsequent to the first decision. This strong relation of the proposed measures of decision uncertainty and perceptual ambiguity should be taken into account when searching for neural correlates of auditory stream segregation.

  3. Decision making and ambiguity in auditory stream segregation

    PubMed Central

    Deike, Susann; Heil, Peter; Böckmann-Barthel, Martin; Brechmann, André

    2015-01-01

    Researchers of auditory stream segregation have largely taken a bottom-up view on the link between physical stimulus parameters and the perceptual organization of sequences of ABAB sounds. However, in the majority of studies, researchers have relied on the reported decisions of the subjects regarding which of the predefined percepts (e.g., one stream or two streams) predominated when subjects listened to more or less ambiguous streaming sequences. When searching for neural mechanisms of stream segregation, it should be kept in mind that such decision processes may contribute to brain activation, as also suggested by recent human imaging data. The present study proposes that the uncertainty of a subject in making a decision about the perceptual organization of ambiguous streaming sequences may be reflected in the time required to make an initial decision. To this end, subjects had to decide on their current percept while listening to ABAB auditory streaming sequences. Each sequence had a duration of 30 s and was composed of A and B harmonic tone complexes differing in fundamental frequency (ΔF). Sequences with seven different ΔF were tested. We found that the initial decision time varied non-monotonically with ΔF and that it was significantly correlated with the degree of perceptual ambiguity defined from the proportions of time the subjects reported a one-stream or a two-stream percept subsequent to the first decision. This strong relation of the proposed measures of decision uncertainty and perceptual ambiguity should be taken into account when searching for neural correlates of auditory stream segregation. PMID:26321899

  4. Annual hypoxia dynamics in an enclosed gulf

    NASA Astrophysics Data System (ADS)

    Kountoura, K.; Zacharias, I.

    2012-04-01

    Hypoxia in coastal environments is a worldwide problem and is expected to worsen in future. Due to the stratification of the water column in many enclosed or semi-enclosed gulfs, deep waters are isolated and hypoxic or anoxic conditions frequently become dominant. The most common method for the oxygenation of these isolated anoxic water masses is vertical mixing. However, there are enclosed gulfs which rarely have the appropriate energy to ensure the mixing of the entire water column. The main purpose of this paper is to find if there are any other hydrodynamic processes which can cause oxygenation of deep waters, apart from vertical mixing. In order to achieve this aim, an enclosed gulf, Amvrakikos in Western Greece, was chosen to be the case study area and bimonthly physicochemical data were collected for one year and used in combination with a three-dimensional model in order to simulate the hydrodynamic circulation of the system. According to our results, another hydrodynamic process can lead to the oxygenation of the deepest water in an enclosed gulf. This process is the horizontal intrusion of well oxygenated water from the open sea. The key factor in determining the success of this horizontal intrusion is the density difference between the deepest area of the enclosed gulf and the open sea outside the gulf. From autumn to winter, when the open sea water is denser than that inside the gulf, the well oxygenated open sea water inflows into the gulf near the bottom sea floor and re-oxygenates the isolated deep waters through mixing. However, from spring to summer, when the deep water of the gulf is characterized by higher density in comparison with the open sea water, the inflow of well oxygenated water stops, causing the development of hypoxic/anoxic conditions during the summer months.

  5. Gulf Cooperation Council: Arabian Gulf Cooperation Continues Defense Forces (Peninsula Shield Force)

    DTIC Science & Technology

    2015-05-23

    The Gulf region serves as one of the most crucial geographic areas in global security . Six Gulf States established the Gulf Cooperation Council...GCC) aimed at political and economic integration and cooperation. However, the mandate has extended to security issues due to increasing instability...in the region. This study analyzes the member countries of the GCC and the strategic roles that they fill on security issues. Further, the study

  6. Shallow Water Dynamics in the Arabian Gulf and Gulf of Oman

    DTIC Science & Technology

    2016-06-07

    Shallow Water Dynamics in the Arabian Gulf and Gulf of Oman Dr. Cheryl Ann Blain Naval Research Laboratory, Ocean Dynamics and Prediction Branch...of a circulation model for the Arabian Gulf and connecting waters that realistically predicts the complex, 3-D circulation and mixing patterns in the...number. 1. REPORT DATE 30 SEP 1999 2. REPORT TYPE 3. DATES COVERED 00-00-1999 to 00-00-1999 4. TITLE AND SUBTITLE Shallow Water Dynamics in

  7. Integrating terrestrial and marine archives of Late Wisconsinan ice stream dynamics in the Canadian Arctic Archipelago

    NASA Astrophysics Data System (ADS)

    Lakeman, Thomas; Blasco, Steve; MacLean, Brian; Bennett, Robbie; England, John; Hughes Clarke, John; Covill, Bob; Patton, Eric

    2014-05-01

    During Late Wisconsinan glaciation the northern Laurentide and Innuitian ice sheets converged over the Canadian Arctic Archipelago. This ice sheet complex included several major ice streams, which constituted important dynamical components. Discharging into the Beaufort Sea and Baffin Bay, these ice streams were a primary control on ice sheet mass balance and ice age sedimentation on adjacent continental margins, including the Arctic Ocean basin. This study presents a new compilation of multibeam echosounder data, sub-bottom profiler data, radiocarbon ages, and marine sediment cores acquired primarily during regional surveys with the CCGS Amundsen. These data characterize the nature and thickness of seafloor sediments in Parry Channel (and many of its connecting channels) and Amundsen Gulf. When combined with the results of terrestrial geomorphological mapping of the adjacent islands, this dataset constrains the maximum extent, chronology, and behaviour of former ice streams in M'Clure Strait, Viscount Melville Sound, Lancaster Sound, and Amundsen Gulf. Importantly, these data highlight complex patterns of past ice stream flow during regional deglaciation. These results contribute to a better understanding of the causal mechanisms that occasioned retreat of the terrestrial and marine sectors of the Laurentide and Innuitian ice sheets. As well, this study helps to quantify past iceberg fluxes to the Arctic Ocean, which has implications for assessing past climate, and the origin of ice-rafted sediment and deep iceberg scours in the Arctic Ocean basin.

  8. In Brief: Gulf of Mexico hypoxia plan

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    2008-06-01

    On 16 June, the Mississippi River/Gulf of Mexico Watershed Nutrient Task Force released an action plan to reduce, mitigate, and control hypoxia in the northern Gulf of Mexico. The plan builds upon a 2001 plan by including more accountability through an annual operating plan, better tracking of progress, and state and federal nutrient reduction strategies. ``Our improved plan unites governments and citizens across the country to take action upstream and along the coast to reduce river nutrient pollution and increase Gulf of Mexico health,'' said U.S. Environmental Protection Agency assistant administrator for water Benjamin Grumbles. For more information, visit http://www.epa.gov/msbasin/.

  9. Nested Gulf of Mexico Modeling with HYCOM

    DTIC Science & Technology

    2005-12-08

    Nested Gulf of Mexico Modeling with HYCOM Patrick J. Hogan Alan J. Wallcraft Naval Research Laboratory Stennis Space Center, MS HYCOM Meeting...valid OMB control number. 1. REPORT DATE DEC 2005 2. REPORT TYPE 3. DATES COVERED 00-00-2005 to 00-00-2005 4. TITLE AND SUBTITLE Nested Gulf of Mexico Modeling...topography is from NRL-DBDB2 • Integrated over 2000-2001 1/25° (~4 km) non-assimilative Nested Gulf of Mexico Possible cross-shelf transport

  10. The Gulf Moment: Arab Relations Since 2011

    DTIC Science & Technology

    2015-05-01

    THE GULF MOMENT: ARAB RElATIONS SINCE 201 t Florence Gaub UNITED STATES ARMY WAR COLLEGE PRESS CarlisleBarracks,PA .., STRENGTH-’WISDOM U.S...SUBTITLE The Gulf Moment: Arab Relations Since 2011 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e...Institute and U.S. Army War College Press THE GULF MOMENT: ARAB RELATIONS SINCE 2011 Florence Gaub May 2015 The views expressed in this report are

  11. 77 FR 32913 - Accountability Measures for the Recreational Sector of Gray Triggerfish in the Gulf of Mexico for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-04

    ... through December 31, 2012. This action is necessary to reduce overfishing of the Gulf gray triggerfish... to prevent overfishing and achieve, on a continuing basis, the optimum yield from federally managed... fishery managers to end overfishing of stocks and to minimize bycatch and bycatch mortality to the...

  12. 77 FR 37330 - Reef Fish Fishery of the Gulf of Mexico; 2012 Commercial Accountability Measure and Closure for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-21

    ... year in the Gulf exclusive economic zone (EEZ). This action is necessary to reduce overfishing of the... Act requires NMFS and regional fishery management councils to prevent overfishing and achieve, on a... further this goal, the Magnuson- Stevens Act requires fishery managers to end overfishing of stocks and...

  13. 78 FR 13284 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; 2013 Accountability Measures for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-27

    ... commercial ACL overage. These actions are necessary to reduce overfishing of the Gulf greater amberjack... end overfishing and prevent overfishing from occurring. AMs are management controls to prevent ACLs... the Magnuson-Stevens Act mandates the establishment of ACLs at a level such that overfishing does...

  14. The Application of Remotely Sensed Data and Models to Benefit Conservation and Restoration Along the Northern Gulf of Mexico Coast

    NASA Astrophysics Data System (ADS)

    Quattrochi, D. A.; Estes, M. G., Jr.; Al-Hamdan, M. Z.; Thom, R.; Woodruff, D.; Judd, C.; Ellis, J. T.; Swann, R.; Johnson, H., III

    2010-12-01

    New data, tools, and capabilities for decision making are significant needs in the northern Gulf of Mexico and other coastal areas. The goal of this project is to support NASA’s Earth Science Mission Directorate and its Applied Science Program and the Gulf of Mexico Alliance by producing and providing NASA data and products that will benefit decision making by coastal resource managers and other end users in the Gulf region. Data and research products are being developed to assist coastal resource managers adapt and plan for changing conditions by evaluating how climate changes and urban expansion will impact land cover/land use (LCLU), hydrodynamics, water properties, and shallow water habitats; to identify priority areas for conservation and restoration; and to distribute datasets to end-users and facilitating user interaction with models. The proposed host sites for data products are NOAA’s National Coastal Data Development Center Regional Ecosystem Data Management, and Mississippi-Alabama Habitat Database. Tools will be available on the Gulf of Mexico Regional Collaborative website with links to data portals to enable end users to employ models and datasets to develop and evaluate LCLU and climate scenarios of particular interest. These data will benefit the Mobile Bay National Estuary Program in ongoing efforts to protect and restore the Fish River watershed and around Weeks Bay National Estuarine Research Reserve. The usefulness of data products and tools will be demonstrated at an end-user workshop.

  15. The Application of Remotely Sensed Data and Models to Benefit Conservation and Restoration Along the Northern Gulf of Mexico Coast

    NASA Technical Reports Server (NTRS)

    Quattrochi, Dale; Estes, Maurice, Jr.; Al-Hamdan, Mohammad; Thom, Ron; Woodruff, Dana; Judd, Chaeli; Ellis, Jean; Swann, Roberta; Johnson, Hoyt, III

    2010-01-01

    New data, tools, and capabilities for decision making are significant needs in the northern Gulf of Mexico and other coastal areas. The goal of this project is to support NASA s Earth Science Mission Directorate and its Applied Science Program and the Gulf of Mexico Alliance by producing and providing NASA data and products that will benefit decision making by coastal resource managers and other end users in the Gulf region. Data and research products are being developed to assist coastal resource managers adapt and plan for changing conditions by evaluating how climate changes and urban expansion will impact land cover/land use (LCLU), hydrodynamics, water properties, and shallow water habitats; to identify priority areas for conservation and restoration; and to distribute datasets to end-users and facilitating user interaction with models. The proposed host sites for data products are NOAA s National Coastal Data Development Center Regional Ecosystem Data Management, and Mississippi-Alabama Habitat Database. Tools will be available on the Gulf of Mexico Regional Collaborative website with links to data portals to enable end users to employ models and datasets to develop and evaluate LCLU and climate scenarios of particular interest. These data will benefit the Mobile Bay National Estuary Program in ongoing efforts to protect and restore the Fish River watershed and around Weeks Bay National Estuarine Research Reserve. The usefulness of data products and tools will be demonstrated at an end-user workshop.

  16. Auditory stream segregation in children with Asperger syndrome

    PubMed Central

    Lepistö, T.; Kuitunen, A.; Sussman, E.; Saalasti, S.; Jansson-Verkasalo, E.; Nieminen-von Wendt, T.; Kujala, T.

    2009-01-01

    Individuals with Asperger syndrome (AS) often have difficulties in perceiving speech in noisy environments. The present study investigated whether this might be explained by deficient auditory stream segregation ability, that is, by a more basic difficulty in separating simultaneous sound sources from each other. To this end, auditory event-related brain potentials were recorded from a group of school-aged children with AS and a group of age-matched controls using a paradigm specifically developed for studying stream segregation. Differences in the amplitudes of ERP components were found between groups only in the stream segregation conditions and not for simple feature discrimination. The results indicated that children with AS have difficulties in segregating concurrent sound streams, which ultimately may contribute to the difficulties in speech-in-noise perception. PMID:19751798

  17. Auditory stream segregation in children with Asperger syndrome.

    PubMed

    Lepistö, T; Kuitunen, A; Sussman, E; Saalasti, S; Jansson-Verkasalo, E; Nieminen-von Wendt, T; Kujala, T

    2009-12-01

    Individuals with Asperger syndrome (AS) often have difficulties in perceiving speech in noisy environments. The present study investigated whether this might be explained by deficient auditory stream segregation ability, that is, by a more basic difficulty in separating simultaneous sound sources from each other. To this end, auditory event-related brain potentials were recorded from a group of school-aged children with AS and a group of age-matched controls using a paradigm specifically developed for studying stream segregation. Differences in the amplitudes of ERP components were found between groups only in the stream segregation conditions and not for simple feature discrimination. The results indicated that children with AS have difficulties in segregating concurrent sound streams, which ultimately may contribute to the difficulties in speech-in-noise perception.

  18. Seafood Contamination after the BP Gulf Oil Spill and Risks to Vulnerable Populations: A Critique of the FDA Risk Assessment

    PubMed Central

    Wong, Karen K.; Solomon, Gina M.

    2011-01-01

    Background: The BP oil spill of 2010 resulted in contamination of one of the most productive fisheries in the United States by polycyclic aromatic hydrocarbons (PAHs). PAHs, which can accumulate in seafood, are known carcinogens and developmental toxicants. In response to the oil spill, the U.S. Food and Drug Administration (FDA) developed risk criteria and established thresholds for allowable levels [levels of concern (LOCs)] of PAH contaminants in Gulf Coast seafood. Objectives: We evaluated the degree to which the FDA’s risk criteria adequately protect vulnerable Gulf Coast populations from cancer risk associated with PAHs in seafood. Discussion: The FDA LOCs significantly underestimate risk from seafood contaminants among sensitive Gulf Coast populations by failing to a) account for the increased vulnerability of the developing fetus and child; b) use appropriate seafood consumption rates; c) include all relevant health end points; and d) incorporate health-protective estimates of exposure duration and acceptable risk. For benzo[a]pyrene and naphthalene, revised LOCs are between two and four orders of magnitude below the level set by the FDA. Comparison of measured levels of PAHs in Gulf seafood with the revised LOCs revealed that up to 53% of Gulf shrimp samples were above LOCs for pregnant women who are high-end seafood consumers. Conclusions: FDA risk assessment methods should be updated to better reflect current risk assessment practices and to protect vulnerable populations such as pregnant women and children. PMID:21990339

  19. Shielded fluid stream injector for particle bed reactor

    SciTech Connect

    Notestein, J.E.

    1991-12-31

    A shielded fluid-stream injector assembly is provided for particle bed reactors. The assembly includes a perforated pipe injector disposed across the particle bed region of the reactor and an inverted V-shaped shield placed over the pipe, overlapping it to prevent descending particles from coming into direct contact with the pipe. The pipe and shield are fixedly secured at one end to the reactor wall and slidably secured at the other end to compensate for thermal expansion. An axially extending housing aligned with the pipe and outside the reactor and an inline reamer are provided for removing deposits from the inside of the pipe. The assembly enables fluid streams to be injected and distributed uniformly into the particle bed with minimized clogging of injector ports. The same design may also be used for extraction of fluid streams from particle bed reactors.

  20. Shielded fluid stream injector for particle bed reactor

    DOEpatents

    Notestein, John E.

    1993-01-01

    A shielded fluid-stream injector assembly is provided for particle bed reactors. The assembly includes a perforated pipe injector disposed across the particle bed region of the reactor and an inverted V-shaped shield placed over the pipe, overlapping it to prevent descending particles from coming into direct contact with the pipe. The pipe and shield are fixedly secured at one end to the reactor wall and slidably secured at the other end to compensate for thermal expansion. An axially extending housing aligned with the pipe and outside the reactor and an in-line reamer are provided for removing deposits from the inside of the pipe. The assembly enables fluid streams to be injected and distributed uniformly into the particle bed with minimized clogging of injector ports. The same design may also be used for extraction of fluid streams from particle bed reactors.

  1. Adaptive dynamic programming for auto-resilient video streaming

    NASA Astrophysics Data System (ADS)

    Zhao, Juan; Li, Xingmei; Wang, Wei; Wu, Guoping

    2007-11-01

    Wireless video transmission encounters higher error rate than in wired network, which introduces distortion into the error-sensitive compressed data, reducing the quality of the playback video. Therefore, to ensure the end-to-end quality, wireless video needs a transmission system including both efficient source coding scheme and transmission technology against the influence of the channel error. This paper tackles a dynamic programming algorithm for robust video streaming over error-prone channels. An auto-resilient multiple-description coding with optimized transmission strategy has been proposed. Further study is done on the computational complexity of rate-distortion optimized video streaming and a dynamic programming algorithm is considered. Experiment results show that video streaming with adaptive dynamic programming gains better playback video quality at the receiver when transmitted through error-prone mobile channel.

  2. The Phoenix stream: A cold stream in the southern hemisphere

    DOE PAGES

    Balbinot, E.

    2016-03-17

    In this study, we report the discovery of a stellar stream in the Dark Energy Survey (DES) Year 1 (Y1A1) data. The discovery was made through simple color-magnitude filters and visual inspection of the Y1A1 data. We refer to this new object as the Phoenix stream, after its resident constellation. After subtraction of the background stellar population we detect a clear signal of a simple stellar population. By fitting the ridge line of the stream in color-magnitude space, we find that a stellar population with agemore » $$\\tau=11.5\\pm0.5$$ Gyr and $[Fe/H]<-1.6$ located 17.5$$\\pm$$0.9 kpc from the Sun gives an adequate description of the stream stellar population. The stream is detected over an extension of 8$$^{\\circ}.$$1 (2.5 kpc) and has a width of $$\\sim$$54 pc assuming a Gaussian profile, indicating that a globular cluster is a probable progenitor. There is no known globular cluster within 5 kpc compatible with being the progenitor of the stream, assuming that the stream traces its orbit. We examined overdensities along the stream, however no obvious counterpart bound stellar system is visible in the coadded images. We also find overdensities along the stream that appear to be symmetrically distributed - consistent with the epicyclic overdensity scenario for the formation of cold streams - as well as a misalignment between the Northern and Southern part of stream. Despite the close proximity we find no evidence that this stream and the halo cluster NGC 1261 have a common accretion origin linked to the recently found EriPhe overdensity (Li et al. 2016).« less

  3. The Phoenix stream: A cold stream in the southern hemisphere

    SciTech Connect

    Balbinot, E.

    2016-03-17

    In this study, we report the discovery of a stellar stream in the Dark Energy Survey (DES) Year 1 (Y1A1) data. The discovery was made through simple color-magnitude filters and visual inspection of the Y1A1 data. We refer to this new object as the Phoenix stream, after its resident constellation. After subtraction of the background stellar population we detect a clear signal of a simple stellar population. By fitting the ridge line of the stream in color-magnitude space, we find that a stellar population with age $\\tau=11.5\\pm0.5$ Gyr and $[Fe/H]<-1.6$ located 17.5$\\pm$0.9 kpc from the Sun gives an adequate description of the stream stellar population. The stream is detected over an extension of 8$^{\\circ}.$1 (2.5 kpc) and has a width of $\\sim$54 pc assuming a Gaussian profile, indicating that a globular cluster is a probable progenitor. There is no known globular cluster within 5 kpc compatible with being the progenitor of the stream, assuming that the stream traces its orbit. We examined overdensities along the stream, however no obvious counterpart bound stellar system is visible in the coadded images. We also find overdensities along the stream that appear to be symmetrically distributed - consistent with the epicyclic overdensity scenario for the formation of cold streams - as well as a misalignment between the Northern and Southern part of stream. Despite the close proximity we find no evidence that this stream and the halo cluster NGC 1261 have a common accretion origin linked to the recently found EriPhe overdensity (Li et al. 2016).

  4. STREAM2016: Streaming Requirements, Experience, Applications and Middleware Workshop

    SciTech Connect

    Fox, Geoffrey; Jha, Shantenu; Ramakrishnan, Lavanya

    2016-10-01

    The Department of Energy (DOE) Office of Science (SC) facilities including accelerators, light sources and neutron sources and sensors that study, the environment, and the atmosphere, are producing streaming data that needs to be analyzed for next-generation scientific discoveries. There has been an explosion of new research and technologies for stream analytics arising from the academic and private sectors. However, there has been no corresponding effort in either documenting the critical research opportunities or building a community that can create and foster productive collaborations. The two-part workshop series, STREAM: Streaming Requirements, Experience, Applications and Middleware Workshop (STREAM2015 and STREAM2016), were conducted to bring the community together and identify gaps and future efforts needed by both NSF and DOE. This report describes the discussions, outcomes and conclusions from STREAM2016: Streaming Requirements, Experience, Applications and Middleware Workshop, the second of these workshops held on March 22-23, 2016 in Tysons, VA. STREAM2016 focused on the Department of Energy (DOE) applications, computational and experimental facilities, as well software systems. Thus, the role of “streaming and steering” as a critical mode of connecting the experimental and computing facilities was pervasive through the workshop. Given the overlap in interests and challenges with industry, the workshop had significant presence from several innovative companies and major contributors. The requirements that drive the proposed research directions, identified in this report, show an important opportunity for building competitive research and development program around streaming data. These findings and recommendations are consistent with vision outlined in NRC Frontiers of Data and National Strategic Computing Initiative (NCSI) [1, 2]. The discussions from the workshop are captured as topic areas covered in this report's sections. The report discusses

  5. Riparian deforestation, stream narrowing, and loss of stream ecosystem services

    PubMed Central

    Sweeney, Bernard W.; Bott, Thomas L.; Jackson, John K.; Kaplan, Louis A.; Newbold, J. Denis; Standley, Laurel J.; Hession, W. Cully; Horwitz, Richard J.

    2004-01-01

    A study of 16 streams in eastern North America shows that riparian deforestation causes channel narrowing, which reduces the total amount of stream habitat and ecosystem per unit channel length and compromises in-stream processing of pollutants. Wide forest reaches had more macroinvertebrates, total ecosystem processing of organic matter, and nitrogen uptake per unit channel length than contiguous narrow deforested reaches. Stream narrowing nullified any potential advantages of deforestation regarding abundance of fish, quality of dissolved organic matter, and pesticide degradation. These findings show that forested stream channels have a wider and more natural configuration, which significantly affects the total in-stream amount and activity of the ecosystem, including the processing of pollutants. The results reinforce both current policy of the United States that endorses riparian forest buffers as best management practice and federal and state programs that subsidize riparian reforestation for stream restoration and water quality. Not only do forest buffers prevent nonpoint source pollutants from entering small streams, they also enhance the in-stream processing of both nonpoint and point source pollutants, thereby reducing their impact on downstream rivers and estuaries. PMID:15381768

  6. Riparian deforestation, stream narrowing, and loss of stream ecosystem services.

    PubMed

    Sweeney, Bernard W; Bott, Thomas L; Jackson, John K; Kaplan, Louis A; Newbold, J Denis; Standley, Laurel J; Hession, W Cully; Horwitz, Richard J

    2004-09-28

    A study of 16 streams in eastern North America shows that riparian deforestation causes channel narrowing, which reduces the total amount of stream habitat and ecosystem per unit channel length and compromises in-stream processing of pollutants. Wide forest reaches had more macroinvertebrates, total ecosystem processing of organic matter, and nitrogen uptake per unit channel length than contiguous narrow deforested reaches. Stream narrowing nullified any potential advantages of deforestation regarding abundance of fish, quality of dissolved organic matter, and pesticide degradation. These findings show that forested stream channels have a wider and more natural configuration, which significantly affects the total in-stream amount and activity of the ecosystem, including the processing of pollutants. The results reinforce both current policy of the United States that endorses riparian forest buffers as best management practice and federal and state programs that subsidize riparian reforestation for stream restoration and water quality. Not only do forest buffers prevent nonpoint source pollutants from entering small streams, they also enhance the in-stream processing of both nonpoint and point source pollutants, thereby reducing their impact on downstream rivers and estuaries.

  7. Probiotic (VSL#3) for Gulf War Illness

    DTIC Science & Technology

    2013-10-01

    TITLE AND SUBTITLE 5a. CONTRACT NUMBER Probiotic (VSL#3) for Gulf War Illness...SUPPLEMENTARY NOTES 14. ABSTRACT The overall objective of the study is to determine whether probiotic VSL#3® will improve 1) intestinal symptoms of

  8. Chronic Fatigue Syndrome in Gulf War Veterans

    MedlinePlus

    ... Z) Hepatitis HIV Mental Health Mental Health Home Suicide Prevention Substance Abuse Military Sexual Trauma PTSD Research ( ... VA benefits, including a Gulf War Registry health exam , the Airborne Hazards and Open Burn Pit Registry , ...

  9. Saudis map $450 million gulf spill cleanup

    SciTech Connect

    Not Available

    1991-11-18

    This paper reports on Saudi Arabia which has earmarked about $450 million to clean up Persian Gulf beaches polluted by history's worst oil spills, created during the Persian Gulf crisis. Details of the proposed cleanup measures were outlined by Saudi environmental officials at a seminar on the environment in Dubai, OPEC News Agency reported. The seminar was sponsored by the Gulf Area Oil Companies Mutual Aid Organization, an environmental cooperative agency set up by Persian Gulf governments. Meantime, a Saudi government report has outlined early efforts designed to contain the massive oil spills that hit the Saudi coast before oil could contaminate water intakes at the huge desalination plants serving Riyadh and cooling water facilities at Al Jubail.

  10. Are Gulf Landfalling Hurricanes Getting Stronger?.

    NASA Astrophysics Data System (ADS)

    Bove, Mark C.; Zierden, David F.; O'Brien, James J.

    1998-07-01

    Recent predictions of increased hurricane activity in the Atlantic basin, as well as explosive coastal population growth, have prompted a study of the trends in quantity and intensity of U.S. landfalling hurricanes in the Gulf of Mexico.Gulf of Mexico hurricane landfalls from Cape Sable, Florida, to Brownsville, Texas, are binned by decade from 1886 to 1995 to determine whether gulf hurricane landfalls are becoming more or less frequent. From these bins, subsets of intense hurricanes (sustained winds of 96 kt or more) per decade are also made. The results show that there is no sign of an increase of hurricane frequency or intensity in the Gulf of Mexico at this time

  11. Hurricane Isaac Moving Towards Northern Gulf Coast

    NASA Video Gallery

    This is an animation of GOES-13 satellite imagery from Aug. 26-28, 2012 of Hurricane Isaac's track through the Gulf of Mexico. Isaac is headed for New Orleans, exactly 7 years after hurricane Katri...

  12. Satellites View Growing Gulf Oil Spill (Update)

    NASA Video Gallery

    On April 30, 2010, the Deepwater Horizon oil rig exploded in the Gulf of Mexico, triggering the largest oil spill in U.S. history. The MODIS instrument, on board NASA's Terra and Aqua satellites, c...

  13. NASA Satellites View Gulf Oil Spill

    NASA Video Gallery

    Two NASA satellites are capturing images of the oil spill in the Gulf of Mexico, which began April 20, 2010, with the explosion of the Deepwater Horizon oil rig. This series of images shows a space...

  14. Persian Gulf: their oil, our need

    SciTech Connect

    Brossard, E.B.

    1984-01-01

    The degree of reliance of the US on Persian Gulf petroleum as well as problems facing Persian Gulf nations are addressed in this report. While US dependency on oil imports from Saudi Arabia is down, Japan and other western allies are very dependent on Saudi oil. The consequences of being deprived of Persian Gulf oil are described. The status and implications of the Iran-Iraq war are discussed in detail. The Arab countries in the region fear attacks on their oil fields by enemies and have developed a regional point defense strategy involving Saudi Arabia, Kuwait, Bahrain, Qatar, the United Arab Emirates and Oman. OPEC's role in the area is described. The possibility of US intervention if needed to keep the Strait of Hormuz open and to protect the Gulf states from violence is also addressed. (DMC)

  15. The 1987 1992 Gulf of Alaska earthquakes

    NASA Astrophysics Data System (ADS)

    Pegler, G.; Das, S.

    1996-06-01

    We present a study of the 1987-1992 Gulf of Alaska earthquake sequence using relocated seismicity data together with body wave analysis of selected larger events. Most of the sequence is located on a N-S-trending fault, directly south of the Yakataga seismic gap and consists of four main events of Mw = 7.2, 7.8, 7.7 and 6.8 and associated aftershocks. The first earthquake is of left-lateral strike-slip type on an ENE-WSW-trending fault. The second event is a right-lateral strike-slip earthquake on the N-S-trending fault. The fault plane of the third strike-slip event was identified as an ENE-WSW-trending fault, located to the south of that for the first event, in a previous study using body wave analysis. We show that though the body wave study cannot unambiguously identify the fault plane, the temporal development of the seismicity together with the pattern of aftershock distribution on the conjugate fault suggests that this event also occurred on the N-S-trending fault and is of right-lateral type. The seismicity on the conjugate fault is interpreted as being triggered by the increase of the shear stress in the direction of the normal to the fault plane due to the main shock. The occurrence of the fourth main shock, a right-lateral strike-slip event in 1992, which itself can be considered an aftershock of the 1987-1988 sequence with epicentres distributed along a N-S-trending fault, favours this conclusion. The first three events of the sequence have been described in earlier studies as having too short a rupture length for their seismic moment. If the rupture lengths inferred from the aftershock zones in this study are used we find that this is not the case. The events in the 1987-1992 sequence lie along magnetic anomaly 13 and related conjugate fracture zones, indicating that the oceanic crust is rupturing along pre-existing zones of weakness in response to plate boundary stresses. At the southern end, the seismic activity terminates near a seamount, which

  16. Qatar Peninsula, United Arab Emirates, Persian Gulf

    NASA Technical Reports Server (NTRS)

    1983-01-01

    In this view of the Qatar Peninsula, United Arab Emirates, Persian Gulf, (25.0N, 51.0E) a large oil spill, seen as a large dark toned mass in the water covers much of the surface of the western Persian Gulf. Qatar is one of several of the oil rich United Arab Emirate states. Oil spills and oil pollution of the environment are common occurrances associated with oil tanker loading operations.

  17. Alabama successes spur interest in eastern Gulf

    SciTech Connect

    Redden, J.

    1985-11-01

    The shallow waters of the eastern fringe of the Gulf of Mexico are becoming a world-class offshore gas play. Spurred by the success ratio offshore Alabama, the water off Mississippi and Florida are drawing intense interest as oil companies attempt to extend the prolific Norphlet formation. Sitting at the heart of the recent interest in the eastern Gulf are the state and federal waters off Alabama. Exploration and drilling activity in the area are discussed.

  18. Returning Persian Gulf Troops: First Year Findings

    DTIC Science & Technology

    1992-03-31

    Congress by April 5, 1992 assessing: 1) needs for rehabilitative services among Persian Gulf returnees who experience Post-Traumatic Stress Disorder...specific relationship between service in the Persian Gulf War and psychological distress. o There is some evidence that stressful pre-deployment experiences...manifestations of War Zone stress . In view of the importance of identifying the delayed emergence of adjustment problems, the National Center for PTSD will

  19. The Southeast Stream Quality Assessment

    USGS Publications Warehouse

    Van Metre, Peter C.; Journey, Celeste

    2014-01-01

    In 2014, the U.S. Geological Survey (USGS) National Water-Quality Assessment Program (NAWQA) is assessing stream quality across the Piedmont and southern Appalachian Mountains in the southeastern United States. The goal of the Southeast Stream Quality Assessment (SESQA) is to characterize multiple water-quality factors that are stressors to aquatic life—contaminants, nutrients, sediment, and streamflow alteration—and the relation of these stressors to ecological conditions in streams throughout the region. Findings will provide communities and policymakers with information on which human and environmental factors are the most critical in controlling stream quality and, thus, provide insights about possible approaches to protect or improve stream quality. The SESQA study will be the second regional study by the NAWQA program, and it will be of similar design and scope as the Midwest Stream Quality Assessment conducted in 2013 (Van Metre and others, 2012).

  20. The California stream quality assessment

    USGS Publications Warehouse

    Van Metre, Peter C.; Egler, Amanda L.; May, Jason T.

    2017-03-06

    In 2017, the U.S. Geological Survey (USGS) National Water-Quality Assessment (NAWQA) project is assessing stream quality in coastal California, United States. The USGS California Stream Quality Assessment (CSQA) will sample streams over most of the Central California Foothills and Coastal Mountains ecoregion (modified from Griffith and others, 2016), where rapid urban growth and intensive agriculture in the larger river valleys are raising concerns that stream health is being degraded. Findings will provide the public and policy-makers with information regarding which human and natural factors are the most critical in affecting stream quality and, thus, provide insights about possible approaches to protect the health of streams in the region.

  1. Fine granularity adaptive multireceiver video streaming

    NASA Astrophysics Data System (ADS)

    Eide, Viktor S. Wold; Eliassen, Frank; Michaelsen, Jørgen Andreas; Jensen, Frank

    2007-01-01

    Effcient delivery of video data over computer networks has been studied extensively for decades. Still, multi-receiver video delivery is challenging, due to heterogeneity and variability in network availability, end node capabilities, and receiver preferences. Our earlier work has shown that content-based networking is a viable technology for fine granularity multireceiver video streaming. By exploiting this technology, we have demonstrated that each video receiver is provided with fine grained and independent selectivity along the different video quality dimensions region of interest, signal to noise ratio for the luminance and the chrominance planes, and temporal resolution. Here we propose a novel adaptation scheme combining such video streaming with state-of-the-art techniques from the field of adaptation to provide receiver-driven multi-dimensional adaptive video streaming. The scheme allows each client to individually adapt the quality of the received video according to its currently available resources and own preferences. The proposed adaptation scheme is validated experimentally. The results demonstrate adaptation to variations in available bandwidth and CPU resources roughly over two orders of magnitude and that fine grained adaptation is feasible given radically different user preferences.

  2. Stream Lifetimes Against Planetary Encounters

    NASA Technical Reports Server (NTRS)

    Valsecchi, G. B.; Lega, E.; Froeschle, Cl.

    2011-01-01

    We study, both analytically and numerically, the perturbation induced by an encounter with a planet on a meteoroid stream. Our analytical tool is the extension of pik s theory of close encounters, that we apply to streams described by geocentric variables. The resulting formulae are used to compute the rate at which a stream is dispersed by planetary encounters into the sporadic background. We have verified the accuracy of the analytical model using a numerical test.

  3. Stream salamanders as indicators of stream quality in Maryland, USA

    USGS Publications Warehouse

    Southerland, M.T.; Jung, R.E.; Baxter, D.P.; Chellman, I.C.; Mercurio, G.; Volstad, J.H.

    2004-01-01

    Biological indicators are critical to the protection of small, headwater streams and the ecological values they provide. Maryland and other state monitoring programs have determined that fish indicators are ineffective in small streams, where stream salamanders may replace fish as top predators. Because of their life history, physiology, abundance, and ubiquity, stream salamanders are likely representative of biological integrity in these streams. The goal of this study was to determine whether stream salamanders are effective indicators of ecological conditions across biogeographic regions and gradients of human disturbance. During the summers of 2001 and 2002, we intensively surveyed for stream salamanders at 76 stream sites located west of the Maryland Coastal Plain, sites also monitored by the Maryland Biological Stream Survey (MBSS) and City of Gaithersburg. We found 1,584 stream salamanders, including all eight species known in Maryland, using two 15 ? 2 m transects and two 4 m2 quadrats that spanned both stream bank and channel. We performed removal sampling on transects to estimate salamander species detection probabilities, which ranged from 0.67-0.85. Stepwise regressions identified 15 of 52 non-salamander variables, representing water quality, physical habitat, land use, and biological conditions, which best predicted salamander metrics. Indicator development involved (1) identifying reference (non-degraded) and degraded sites (using percent forest, shading, riparian buffer width, aesthetic rating, and benthic macroinvertebrate and fish indices of biotic integrity); (2) testing 12 candidate salamander metrics (representing species richness and composition, abundance, species tolerance, and reproductive function) for their ability to distinguish reference from degraded sites; and (3) combining metrics into an index that effectively discriminated sites according to known stream conditions. Final indices for Highlands, Piedmont, and Non-Coastal Plain

  4. The Phoenix Stream: A Cold Stream in the Southern Hemisphere

    NASA Astrophysics Data System (ADS)

    Balbinot, E.; Yanny, B.; Li, T. S.; Santiago, B.; Marshall, J. L.; Finley, D. A.; Pieres, A.; Abbott, T. M. C.; Abdalla, F. B.; Allam, S.; Benoit-Lévy, A.; Bernstein, G. M.; Bertin, E.; Brooks, D.; Burke, D. L.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Cunha, C. E.; da Costa, L. N.; DePoy, D. L.; Desai, S.; Diehl, H. T.; Doel, P.; Estrada, J.; Flaugher, B.; Frieman, J.; Gerdes, D. W.; Gruen, D.; Gruendl, R. A.; Honscheid, K.; James, D. J.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; March, M.; Martini, P.; Miquel, R.; Nichol, R. C.; Ogando, R.; Romer, A. K.; Sanchez, E.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Tarle, G.; Thomas, D.; Tucker, D.; Walker, A. R.; DES Collaboration

    2016-03-01

    We report the discovery of a stellar stream in the Dark Energy Survey Year 1 (Y1A1) data. The discovery was made through simple color-magnitude filters and visual inspection of the Y1A1 data. We refer to this new object as the Phoenix stream, after its resident constellation. After subtraction of the background stellar population we detect a clear signal of a simple stellar population. By fitting the ridge line of the stream in color-magnitude space, we find that a stellar population with age τ = 11.5 ± 0.5 Gyr and [Fe/H] < -1.6, located 17.5 ± 0.9 kpc from the Sun, gives an adequate description of the stream stellar population. The stream is detected over an extension of 8.°1 (2.5 kpc) and has a width of ˜54 pc assuming a Gaussian profile, indicating that a globular cluster (GC) is a probable progenitor. There is no known GC within 5 kpc that is compatible with being the progenitor of the stream, assuming that the stream traces its orbit. We examined overdensities (ODs) along the stream, however, no obvious counterpart-bound stellar system is visible in the coadded images. We also find ODs along the stream that appear to be symmetrically distributed—consistent with the epicyclic OD scenario for the formation of cold streams—as well as a misalignment between the northern and southern part of stream. Despite the close proximity we find no evidence that this stream and the halo cluster NGC 1261 have a common accretion origin linked to the recently found EriPhe OD.

  5. Analyzing indicators of stream health for Minnesota streams

    USGS Publications Warehouse

    Singh, U.; Kocian, M.; Wilson, B.; Bolton, A.; Nieber, J.; Vondracek, B.; Perry, J.; Magner, J.

    2005-01-01

    Recent research has emphasized the importance of using physical, chemical, and biological indicators of stream health for diagnosing impaired watersheds and their receiving water bodies. A multidisciplinary team at the University of Minnesota is carrying out research to develop a stream classification system for Total Maximum Daily Load (TMDL) assessment. Funding for this research is provided by the United States Environmental Protection Agency and the Minnesota Pollution Control Agency. One objective of the research study involves investigating the relationships between indicators of stream health and localized stream characteristics. Measured data from Minnesota streams collected by various government and non-government agencies and research institutions have been obtained for the research study. Innovative Geographic Information Systems tools developed by the Environmental Science Research Institute and the University of Texas are being utilized to combine and organize the data. Simple linear relationships between index of biological integrity (IBI) and channel slope, two-year stream flow, and drainage area are presented for the Redwood River and the Snake River Basins. Results suggest that more rigorous techniques are needed to successfully capture trends in IBI scores. Additional analyses will be done using multiple regression, principal component analysis, and clustering techniques. Uncovering key independent variables and understanding how they fit together to influence stream health are critical in the development of a stream classification for TMDL assessment.

  6. ASSESSING STREAM BED STABILITY AND EXCESS SEDIMENTATION IN MOUNTAIN STREAMS

    EPA Science Inventory

    Land use and resource exploitation in headwaters catchments?such as logging, mining, and road building?often increase sediment supply to streams, potentially causing excess sedimentation. Decreases in mean substrate size and increases in fine stream bed sediments can lead to inc...

  7. An initial SPARROW model of land use and in-stream controls on total organic carbon in streams of the conterminous United States

    USGS Publications Warehouse

    Shih, Jhih-Shyang; Alexander, Richard B.; Smith, Richard A.; Boyer, Elizabeth W.; Shwarz, Grogory E.; Chung, Susie

    2010-01-01

    phytoplankton in lakes and streams. The largest contributors per unit of drainage area to the mean annual stream TOC load among the terrestrial sources are, in descending order: wetlands, urban lands, mixed forests, agricultural lands, evergreen forests, and deciduous forests . It was found that the SPARROW model estimates of TOC contributions to streams associated with these land uses are also consistent with literature estimates. SPARROW model calibration results are used to simulate the delivery of TOC loads to the coastal areas of seven major regional drainages. It was found that stream photosynthesis is the largest source of the TOC yields ( about 50 percent) delivered to the coastal waters in two of the seven regional drainages (the Pacific Northwest and Mississippi-Atchafalaya-Red River basins ), whereas terrestrial sources are dominant (greater than 60 percent) in all other regions (North Atlantic, South Atlantic-Gulf, California, Texas-Gulf, and Great Lakes).

  8. Horizontal movements of Atlantic blue marlin (Makaira nigricans) in the Gulf of Mexico

    USGS Publications Warehouse

    Kraus, R.T.; Wells, R.J.D.; Rooker, J.R.

    2011-01-01

    We examined movements of Atlantic blue marlin (Makaira nigricans) from the Gulf of Mexico based upon 42 pop-up archival transmitting (PAT) tags. Long deployments (including one 334-day track) revealed diverse movement patterns within the Gulf of Mexico. North-south seasonal changes in blue marlin distribution showed strong correspondence with established seasonal patterns of sea surface temperature and primary production. During the summer spawning season, blue marlin utilized outer shelf and shelf edge waters in the northern Gulf of Mexico, and longer duration tracks indicated overwintering habitats in the Bay of Campeche. Egress occurred throughout the year and was difficult to determine because some tracks ended in the Straits of Florida (n = 3) while other tracks recorded movement through it or the Yucatan Channel (n = 4). Our results indicate that Atlantic blue marlin have a more restricted geographic range of habitats than previously recognized and that the Gulf of Mexico provides spatially dynamic suitable habitat that is utilized year-round through seasonal movements. ?? 2011 Springer-Verlag.

  9. Chemical warfare and the Gulf War: a review of the impact on Gulf veterans' health.

    PubMed

    Riddle, James R; Brown, Mark; Smith, Tyler; Ritchie, Elspeth Cameron; Brix, Kelley Ann; Romano, James

    2003-08-01

    It is unlikely that Gulf War veterans are suffering chronic effects from illnesses caused by chemical warfare nerve agent exposure. Extensive investigation and review by several expert panels have determined that no evidence exists that chemical warfare nerve agents were used during the Gulf War. At no time before, during, or after the war was there confirmation of symptoms among anyone, military or civilian, caused by chemical warfare nerve agent exposure. However, studies of Gulf War veterans have found belief that chemical weapons were used, significantly associated with both severe and mild-moderate illnesses. The psychological impact of a chemical warfare attack, either actual or perceived, can result in immediate and long-term health consequences. The deployment or war-related health impact from life-threatening experiences of the Gulf War, including the perceived exposure to chemical warfare agents, should be considered as an important cause of morbidity among Gulf War veterans.

  10. Hydrologic connectivity and the contribution of stream headwaters to ecological integrity at regional scales

    USGS Publications Warehouse

    Freeman, Mary C.; Pringle, C.M.; Jackson, C.R.

    2007-01-01

    Cumulatively, headwater streams contribute to maintaining hydrologic connectivity and ecosystem integrity at regional scales. Hydrologic connectivity is the water-mediated transport of matter, energy and organisms within or between elements of the hydrologic cycle. Headwater streams compose over two-thirds of total stream length in a typical river drainage and directly connect the upland and riparian landscape to the rest of the stream ecosystem. Altering headwater streams, e.g., by channelization, diversion through pipes, impoundment and burial, modifies fluxes between uplands and downstream river segments and eliminates distinctive habitats. The large-scale ecological effects of altering headwaters are amplified by land uses that alter runoff and nutrient loads to streams, and by widespread dam construction on larger rivers (which frequently leaves free-flowing upstream portions of river systems essential to sustaining aquatic biodiversity). We discuss three examples of large-scale consequences of cumulative headwater alteration. Downstream eutrophication and coastal hypoxia result, in part, from agricultural practices that alter headwaters and wetlands while increasing nutrient runoff. Extensive headwater alteration is also expected to lower secondary productivity of river systems by reducing stream-system length and trophic subsidies to downstream river segments, affecting aquatic communities and terrestrial wildlife that utilize aquatic resources. Reduced viability of freshwater biota may occur with cumulative headwater alteration, including for species that occupy a range of stream sizes but for which headwater streams diversify the network of interconnected populations or enhance survival for particular life stages. Developing a more predictive understanding of ecological patterns that may emerge on regional scales as a result of headwater alterations will require studies focused on components and pathways that connect headwaters to river, coastal and

  11. Early Late Cretaceous to Holocene seismic stratigraphy and geologic history of southeastern Gulf of Mexico

    SciTech Connect

    Angstadt, D.M.; Austin, J.A.; Buffler, R.T.

    1985-06-01

    Multifold seismic reflection profiles were used in conjunction with results from Deep Sea Drilling Project (DSDP) Leg 77 to interpret the early Late Cretaceous to Holocene geologic history of the southeastern Gulf of Mexico. During the mid-Cenomanian(.) to early Paleocene(.), this region began to record the effects of a collision between a northward-migrating island arc (now part of Cuba) and a salient of the North American plate. More than 2 km (6,560 ft) of gravity-flow deposits accumulated in an elongate structural corridor or foredeep along the base of the modern Cuban slope, while the slope itself was the site of both folding and overthrusting. Clastics continued to dominate the depositional regime until the late Eocene, at which time the Cuban arc had been firmly welded to North America. A late middle to early late Eocene hiatus in Site 540, which coincides with a prominent regional seismic unconformity, marks the transition from predominantly terrigenous input to pelagic/hemipelagic deposition. Since the late Eocene, the southeastern gulf has recorded multiple cycles of deposition and erosion. Unconformities displayed on seismic profiles are numerous. Erosional agents have included the Gulf Stream system, and turbidity currents and debris flows concentrated in the vicinity of submarine canyons. Continuing slope instability is indicated by slide/slump planes along canyon walls.

  12. The End of the End of Ideology

    ERIC Educational Resources Information Center

    Jost, John T.

    2006-01-01

    The "end of ideology" was declared by social scientists in the aftermath of World War II. They argued that: (1) ordinary citizens' political attitudes lack the kind of stability, consistency, and constraint that ideology requires; (2) ideological constructs such as liberalism and conservatism lack motivational potency and behavioral…

  13. Human impacts to mountain streams

    NASA Astrophysics Data System (ADS)

    Wohl, Ellen

    2006-09-01

    Mountain streams are here defined as channel networks within mountainous regions of the world. This definition encompasses tremendous diversity of physical and biological conditions, as well as history of land use. Human effects on mountain streams may result from activities undertaken within the stream channel that directly alter channel geometry, the dynamics of water and sediment movement, contaminants in the stream, or aquatic and riparian communities. Examples include channelization, construction of grade-control structures or check dams, removal of beavers, and placer mining. Human effects can also result from activities within the watershed that indirectly affect streams by altering the movement of water, sediment, and contaminants into the channel. Deforestation, cropping, grazing, land drainage, and urbanization are among the land uses that indirectly alter stream processes. An overview of the relative intensity of human impacts to mountain streams is provided by a table summarizing human effects on each of the major mountainous regions with respect to five categories: flow regulation, biotic integrity, water pollution, channel alteration, and land use. This table indicates that very few mountains have streams not at least moderately affected by land use. The least affected mountainous regions are those at very high or very low latitudes, although our scientific ignorance of conditions in low-latitude mountains in particular means that streams in these mountains might be more altered than is widely recognized. Four case studies from northern Sweden (arctic region), Colorado Front Range (semiarid temperate region), Swiss Alps (humid temperate region), and Papua New Guinea (humid tropics) are also used to explore in detail the history and effects on rivers of human activities in mountainous regions. The overview and case studies indicate that mountain streams must be managed with particular attention to upstream/downstream connections, hillslope

  14. Acoustic streaming related to minor loss phenomenon in differentially heated elements of thermoacoustic devices

    NASA Astrophysics Data System (ADS)

    Mironov, Mikhail; Gusev, Vitalyi; Auregan, Yves; Lotton, Pierrick; Bruneau, Michel; Piatakov, Pavel

    2002-08-01

    It is demonstrated that the differentially heated stack, the heart of all thermoacoustic devices, provides a source of streaming additional to those associated with Reynolds stresses in quasi-unidirectional gas flow. This source of streaming is related to temperature-induced asymmetry in the generation of vortices and turbulence near the stack ends. The asymmetry of the hydrodynamic effects in an otherwise geometrically symmetric stack is due to the temperature difference between stack ends. The proposed mechanism of streaming excitation in annular thermoacoustic devices operates even in the absence of thermo-viscous interaction of sound waves with resonator walls. copyright 2002 Acoustical Society of America.

  15. MEASURED AND PREFORMED PHOSPHATE IN THE GULF OF MEXICO REGION.

    DTIC Science & Technology

    Measured and preformed phosphate-phosphorous versus depth are presented for three recent cruises to the Gulf of Mexico region. Phosphate...are discussed for a hypothetical idealized station in the Gulf of Mexico . (Author)

  16. Memorandum of Understanding with the Mississippi Gulf Coast Community College

    EPA Pesticide Factsheets

    The purpose of the Memorandum of Understanding is to increase cooperation between Mississippi Gulf Coast Community College and the U.S Environmental Protection Agency’s Gulf of Mexico Program in areas of mutual interest.

  17. Mississippi Resident Receives First Place EPA Gulf Guardian Award

    EPA Pesticide Factsheets

    ATLANTA - The U.S. Environmental Protection Agency's (EPA) Gulf of Mexico Program recognized Mississippi resident Tracie Sempier with the First Place 2015 Gulf Guardian Award in the Individual Category. The awards ceremony was held today at the Texa

  18. Surface dispersion in the Gulf of California

    NASA Astrophysics Data System (ADS)

    Zavala Sansón, L.

    2015-09-01

    Surface dispersion is measured in the Gulf of California by means of Argos drifters released along this semi-enclosed, elongated basin. First, basic one-particle statistics (Lagrangian scales, absolute dispersion and diffusion coefficients) are estimated along and across the Gulf. Absolute dispersion shows a nearly ballistic regime during the Lagrangian time scale (<2 days) in both directions (it grows as ∼t2, where t is time). During the subsequent 30 days, absolute dispersion enters a random-walk regime (∼t) along the Gulf, while being saturated across the basin due to the lateral boundaries. Secondly, the analysis is extended to two-particle statistics (relative dispersion between pairs of drifters and Finite Scale Lyapunov Exponents, FSLE). Relative dispersion is nearly exponential in both directions during the first few days, though evidence is not conclusive. During the subsequent 30 days, it grows as ∼t1.5 along the Gulf, while being saturated across the basin again. It is shown that relative dispersion along the Gulf is proportional to t̂3 , where t ̂ represents a shifted time that depends on the initial separation of the particles. This form of the Richardson regime is consistently measured for particles that are sufficiently separated (30 km or more). The Richardson regime is verified with the FSLE for particle separations ranging from 30 to 140 km, approximately. The obtained dispersion properties are discussed in terms of the main circulation features within the basin, such as mesoscale vortices that occupy the width of the Gulf. These structures might retain buoys during days or weeks, thus preventing or delaying further displacements and therefore affecting the particle dispersion. The vortices are also an important mechanism to translate particles across the Gulf, between the Peninsula and the continent, thus promoting the saturation of dispersion along this direction.

  19. StreamLab Collaboratory: Experiments, data sets, and research synthesis

    NASA Astrophysics Data System (ADS)

    Singh, Arvind; Czuba, Jonathan A.; Foufoula-Georgiou, Efi; Marr, Jeffrey D. G.; Hill, Craig; Johnson, Sara; Ellis, Chris; Mullin, James; Orr, Cailin H.; Wilcock, Peter R.; Hondzo, Miki; Paola, Chris

    2013-03-01

    A series of community-led, large-scale laboratory experiments, termed "StreamLab", were performed by the National Center for Earth-surface Dynamics (NCED) with the purpose of advancing multidisciplinary research, education, and knowledge transfer at the interface of physical/chemical/biological processes in streams, science-based stream restoration practice, and environmental sensing technologies. Two series of experiments, StreamLab06 and StreamLab08, were conducted in the Main Channel of the St. Anthony Falls Laboratory at the University of Minnesota, a flume 84 m long and 2.75 m wide with water fed by the Mississippi River at a rate of up to 8.5 m3/s. The purpose of this paper is to share with the broader community the data collected with the hope of stimulating further analysis and future experimental campaigns toward advancing our predictive understanding of the physical, chemical, and biological processes in streams. Toward this end, a brief summary of the results to date is included and some ideas for further research are provided.

  20. Electrophysiological Evidence for Ventral Stream Deficits in Schizophrenia Patients

    PubMed Central

    Plomp, Gijs; Roinishvili, Maya; Chkonia, Eka; Kapanadze, George; Kereselidze, Maia; Brand, Andreas; Herzog, Michael H.

    2013-01-01

    Schizophrenic patients suffer from many deficits including visual, attentional, and cognitive ones. Visual deficits are of particular interest because they are at the fore-end of information processing and can provide clear examples of interactions between sensory, perceptual, and higher cognitive functions. Visual deficits in schizophrenic patients are often attributed to impairments in the dorsal (where) rather than the ventral (what) stream of visual processing. We used a visual-masking paradigm in which patients and matched controls discriminated small vernier offsets. We analyzed the evoked electroencephalography (EEG) responses and applied distributed electrical source imaging techniques to estimate activity differences between conditions and groups throughout the brain. Compared with controls, patients showed strongly reduced discrimination accuracy, confirming previous work. The behavioral deficits corresponded to pronounced decreases in the evoked EEG response at around 200 ms after stimulus onset. At this latency, patients showed decreased activity for targets in left parietal cortex (dorsal stream), but the decrease was most pronounced in lateral occipital cortex (in the ventral stream). These deficiencies occurred at latencies that reflect object processing and fine shape discriminations. We relate the reduced ventral stream activity to deficient top-down processing of target stimuli and provide a framework for relating the commonly observed dorsal stream deficiencies with the currently observed ventral stream deficiencies. PMID:22258884

  1. Plate interactions control middle late Miocene, proto-Gulf and Basin and Range extension in the southern Basin and Range

    NASA Astrophysics Data System (ADS)

    Henry, Christopher D.; Aranda-Gomez, J. Jorge

    2000-03-01

    Middle-late Miocene (proto-Gulf; ˜12-6 Ma) extension around the Gulf of California (Gulf Extensional Province) is commonly interpreted as resulting from partitioning of oblique Pacific-North American plate motion into strike-slip displacement along the margin and east-northeast extension perpendicular to the margin within the North American plate. We propose that this mechanism also applies to kinematically similar, predominantly east-northeast extension that occurred at the same time throughout the southern Basin and Range province, from southern Arizona and New Mexico to the Trans-Mexican Volcanic Belt. New field and 40Ar/ 39Ar data in Sinaloa and Durango confirm that this episode of extension occurred on the mainland side of the Gulf and in the Basin and Range east of the Sierra Madre Occidental, which is generally considered the eastern margin of the Gulf Extensional Province. Published data indicate the middle-late Miocene episode also occurred across the northern and southern ends of the Sierra Madre where the Gulf Extensional Province connects with the Basin and Range: (1) from central Sonora into southern Arizona and New Mexico, and (2) from Nayarit into central Mexico north of the Trans-Mexican Volcanic Belt. This episode appears to have affected an area that continues to the eastern edge of the Basin and Range province in Texas and San Luis Potosi. Recognition that this episode of extension affected the entire southern Basin and Range resolves the discrepancy between the amount of extension calculated based on plate reconstructions and that based on field data within the Gulf Extensional Province alone. Published plate reconstructions require 160 to 110 km of east-northeast extension between ˜12 and 6 Ma. If taken up solely within the Gulf Extensional Province, this would have generated 66 to 78% extension, which is much greater than observed. Spread across the entire southern Basin and Range it requires only ˜20% total extension, which is more

  2. Ice mass loss in Greenland, the Gulf of Alaska, and the Canadian Archipelago: Seasonal cycles and decadal trends

    NASA Astrophysics Data System (ADS)

    Harig, Christopher; Simons, Frederik J.

    2016-04-01

    Over the past several decades mountain glaciers and ice caps have been significant contributors to sea level rise. Here we estimate the ice mass changes in the Canadian Archipelago, the Gulf of Alaska, and Greenland since 2003 by analyzing time-varying gravimetry data from the Gravity Recovery and Climate Experiment. Prior to 2013, interannual ice mass variability in the Gulf of Alaska and in regions around Greenland remains within the average estimated over the whole data span. Beginning in summer 2013, ice mass in regions around Greenland departs positively from its long-term trend. Over Greenland this anomaly reached almost 500 Gt through the end of 2014. Overall, long-term ice mass loss from Greenland and the Canadian Archipelago continues to accelerate, while losses around the Gulf of Alaska region continue but remain steady with no significant acceleration.

  3. We All Stream for Video

    ERIC Educational Resources Information Center

    Technology & Learning, 2008

    2008-01-01

    More than ever, teachers are using digital video to enhance their lessons. In fact, the number of schools using video streaming increased from 30 percent to 45 percent between 2004 and 2006, according to Market Data Retrieval. Why the popularity? For starters, video-streaming products are easy to use. They allow teachers to punctuate lessons with…

  4. Industrial-Strength Streaming Video.

    ERIC Educational Resources Information Center

    Avgerakis, George; Waring, Becky

    1997-01-01

    Corporate training, financial services, entertainment, and education are among the top applications for streaming video servers, which send video to the desktop without downloading the whole file to the hard disk, saving time and eliminating copyrights questions. Examines streaming video technology, lists ten tips for better net video, and ranks…

  5. Save Our Streams and Waterways.

    ERIC Educational Resources Information Center

    Indiana State Dept. of Education, Indianapolis. Center for School Improvement and Performance.

    Protection of existing water supplies is critical to ensuring good health for people and animals alike. This program is aligned with the Izaak Walton League of American's Save Our Streams program which is based on the concept that students can greatly improve the quality of a nearby stream, pond, or river by regular visits and monitoring. The…

  6. The Asphalt Ecosystem of the Gulf of Mexico: Results From the Chapopote III Cruise

    NASA Astrophysics Data System (ADS)

    MacDonald, I. R.; Escobar, E.; Naehr, T.; Joye, S.; Spiess, V.; Cruise Participants, C.

    2007-12-01

    The Campeche Knolls region of the southern Gulf of Mexico contains numerous diapiric mounds and ridges that are associated with persistent oil slicks and extensive flows of solidified asphalt. Previous investigations1 have documented chemosynthetic communities, gas hydrates, and bubble streams that rise hundreds of meters into the water column. However, only a few of the potential features had previously been investigated. The team2 selected a series of potential sites based on satellite images of oil slicks and geophysical data. These sites were surveyed during a cruise with the Mexican ship JUSTO SIERRA during 11-24 September 2007. Visual surveys using video and digital images were completed over geophysical anomalies. Multi-corer samples of the sediments were then collected based on the visual data. A narrow beam acoustic profiler was used to search for bubble streams. Preliminary results of this expedition are presented. 1 MacDonald, I. R., et al. (2004). "Asphalt volcanism and chemosynthetic life, Campeche Knolls, Gulf of Mexico." Science 304: 999-1002. 2 Chapopote III cruise participants: J. Adams, L. F. Alvarez, J. Bliss, M. Bowells, F. Deng, E. Escobar, O. Garcia, M. M. L. Garduño, A. Gassner, K. Hunter, B. B. Jimenez, A. Leiva, I. MacDonald, T. Naehr, D. Prouty, V. Samarkin, and J. Wood.

  7. Case study: student perceptions of video streaming nursing class sessions.

    PubMed

    Wall Parilo, Denise M; Parsh, Bridget

    2014-03-01

    Due to space constraints, students in their pediatric and obstetrical nursing courses received lecture in two formats: live lecture and video-streamed lecture. Live lecture is the traditional classroom format of live, in-person lecture without recording archives, whereas video streaming is live (synchronous) online lecture, also recorded for digital archive (asynchronous viewing). At the end of the semester, students (N = 53) responded to a survey about what they liked about both methods of instruction. Results reveal strengths of both methods and suggest ways to make both methods more effective.

  8. Visual tracking and localization of billboards in streamed soccer matches

    NASA Astrophysics Data System (ADS)

    Aldershoff, Frank; Gevers, Theo

    2003-12-01

    In this paper we present a system for the localisation and tracking of billboards in streamed soccer matches. The application area for this research is the delivery of customised content to end users. When international soccer matches are broadcast, the diversity of the audience is very large and advertisers would like to be able to adapt the billboards to the different audiences. By replacing the billboards in the video stream this can be achieved. In order to build a more robust system, photometric invariant features are used. These colour features are less susceptible to the changes in illumination. Sensor noise is dealt with through variable kernel density estimation.

  9. Dynamical modelling of meteoroid streams

    NASA Astrophysics Data System (ADS)

    Clark, D. L.; Wiegert, P. A.

    2014-07-01

    Accurate simulations of meteoroid streams permit the prediction of stream interaction with Earth, and provide a measure of risk to Earth satellites and interplanetary spacecraft. Current cometary ejecta and meteoroid stream models have been somewhat successful in predicting some stream observations, but have required significant assumptions and simplifications. Extending on the approach of Vaubaillon et al. 2005, we model dust ejection from the cometary nucleus, and generate sample particles representing bins of distinct dynamical evolution-regulating characteristics (size, density, direction, albedo). Ephemerides of the sample particles are integrated and recorded for later assignment of weights based on model parameter changes. To assist in model analysis we are developing interactive software to permit the "turning of knobs" of model parameters, allowing for near-real-time 3D visualization of resulting stream structure. Using the tool, we will revisit prior assumptions made, and will observe the impact of introducing non-uniform and time-variant cometary surface attributes and processes.

  10. Stream Clustering of Growing Objects

    NASA Astrophysics Data System (ADS)

    Siddiqui, Zaigham Faraz; Spiliopoulou, Myra

    We study incremental clustering of objects that grow and accumulate over time. The objects come from a multi-table stream e.g. streams of Customer and Transaction. As the Transactions stream accumulates, the Customers’ profiles grow. First, we use an incremental propositionalisation to convert the multi-table stream into a single-table stream upon which we apply clustering. For this purpose, we develop an online version of K-Means algorithm that can handle these swelling objects and any new objects that arrive. The algorithm also monitors the quality of the model and performs re-clustering when it deteriorates. We evaluate our method on the PKDD Challenge 1999 dataset.

  11. FireHose Streaming Benchmarks

    SciTech Connect

    Karl Anderson, Steve Plimpton

    2015-01-27

    The FireHose Streaming Benchmarks are a suite of stream-processing benchmarks defined to enable comparison of streaming software and hardware, both quantitatively vis-a-vis the rate at which they can process data, and qualitatively by judging the effort involved to implement and run the benchmarks. Each benchmark has two parts. The first is a generator which produces and outputs datums at a high rate in a specific format. The second is an analytic which reads the stream of datums and is required to perform a well-defined calculation on the collection of datums, typically to find anomalous datums that have been created in the stream by the generator. The FireHose suite provides code for the generators, sample code for the analytics (which users are free to re-implement in their own custom frameworks), and a precise definition of each benchmark calculation.

  12. Verification of the Gulf of Mexico Hindcast Wave Information

    DTIC Science & Technology

    1992-09-01

    The Wave Information Study (WIS) for the Gulf of Mexico (WIS Report 18) provides a wave climate for the US shorelines of the Gulf of Mexico based on...conditions. In 1991, CERC conducted a 1-year hindcast of the Gulf of Mexico for the year 1988 and evaluated the model results against extensive wind and wave...and guidance on the use of the earlier WIS study.... Gulf of Mexico , Hindcast, Waves.

  13. End of life care.

    PubMed

    Williams, Ruth

    2012-01-26

    The combination of an ageing population and increasing numbers of prisoners means delivering end of life care in prisons is inevitable. To this end the National End of Life Programme has published a practical guide, aimed at health and social care workers, and prison staff. The guide outlines the six steps of the end of life care pathway in detail, from initiating discussions to care after death. It also includes case studies highlighting best practice. To read the guide, visit http://tinyurl.com/ndoflifeinprison.

  14. INTEGRATED COASTAL MONITORING PROGRAM FOR THE GULF OF MEXICO

    EPA Science Inventory

    The Gulf of Mexico Program (GMP) Office in cooperation with Gulf State agencies, EPA Regions 4 and 6, EPA's Office of Water and Office of Research and Development (ORD), and the GMP principal partners are developing an integrated coastal monitoring program for the Gulf of Mexico....

  15. 75 FR 33296 - Columbia Gulf Transmission Company; Notice of Filing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-11

    ... Energy Regulatory Commission Columbia Gulf Transmission Company; Notice of Filing June 2, 2010. Take notice that on May 20, 2010, Columbia Gulf Transmission Company (Columbia Gulf), 5151 San Felipe, Suite... operate minor facilities required to isolate a portion of its existing transmission system to...

  16. 50 CFR Appendix B to Part 622 - Gulf Areas

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Gulf Areas B Appendix B to Part 622..., DEPARTMENT OF COMMERCE FISHERIES OF THE CARIBBEAN, GULF, AND SOUTH ATLANTIC Pt. 622, App. B Appendix B to Part 622—Gulf Areas Table 1 of Appendix B to Part 622—Seaward Coordinates of the Longline and Buoy...

  17. 3 CFR - Long-Term Gulf Coast Restoration Support Plan

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 3 The President 1 2011-01-01 2011-01-01 false Long-Term Gulf Coast Restoration Support Plan Presidential Documents Other Presidential Documents Memorandum of June 30, 2010 Long-Term Gulf Coast... help the Gulf Coast and its people recover from this tragedy. A long-term plan to restore the...

  18. 50 CFR 622.47 - Gulf groundfish trawl fishery.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... closure. (b) Other provisions of this part notwithstanding, a dealer in a Gulf state is exempt from the... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Gulf groundfish trawl fishery. 622.47... ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE FISHERIES OF THE CARIBBEAN, GULF, AND SOUTH...

  19. 76 FR 65321 - Gulf War Veterans' Illnesses Task Force

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-20

    ... AFFAIRS Gulf War Veterans' Illnesses Task Force AGENCY: Department of Veterans Affairs (VA). ACTION... the Gulf War Veterans' Illnesses Task Force (GWVI-TF) in August 2009 to conduct a comprehensive review of VA's approach to and programs addressing 1990-1991 Gulf War Veterans' illnesses. The second...

  20. 78 FR 28292 - Gulf War Veterans' Illnesses Task Force

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-14

    ... AFFAIRS Gulf War Veterans' Illnesses Task Force AGENCY: Department of Veterans Affairs (VA). ACTION... the Gulf War Veterans' Illnesses Task Force (GWVI-TF) in August 2009 to conduct a comprehensive review of VA's approach to and programs addressing 1990-1991 Gulf War Veterans' illnesses. The third...

  1. Fate of acetone in an outdoor model stream in southern Mississippi, U.S.A.

    USGS Publications Warehouse

    Rathbun, R.E.; Stephens, D.W.; Shultz, D.J.; Tai, D.Y.

    1988-01-01

    The fate of acetone in water was investigated in an outdoor model stream located in southern Mississippi, U.S.A. Acetone was injected continuously for 32 days resulting in small milligram-perliter concentrations in the stream. Rhodamine-WT dye was injected at the beginning and at the end of the study to determine the time-of-travel and dispersion characteristics of the stream. A 12-h injection of t-butyl alcohol (TBA) was used to determine the volatilization characteristics of the stream. Volatilization controlled the acetone concentration in the stream. Significant bacterial degradation of acetone did not occur, contrary to expectations based on previous laboratory studies. Attempts to induce degradation of the acetone by injecting glucose and a nutrient solution containing bacteria acclimated to acetone were unsuccessful. Possible explanations for the lack of bacterial degradation included a nitrate limitation and a limited residence time in the stream system. ?? 1988.

  2. How Deltas Die - a Case Study of the End of Sedimentation in Two Giant Deltas

    NASA Astrophysics Data System (ADS)

    Macdonald, D.; Robinson, P.; Nicholson, U.

    2013-12-01

    Most well-studied deltas are on passive margins (e.g. Mississippi, Rhone, Ebro), where the main tectonic control on accommodation space is thermal subsidence. As long as the main river in the sediment routing system keeps flowing, there is no particular reason for sedimentation to end, and some deltas have a history extending more than 100 Ma (e.g. Niger at 130 Ma). However, some very large deltas can build out over active margins. For example, the Amur, Orinoco, and Colorado (US) deltas all straddle strike-slip plate boundaries and are much less long-lived than their passive margin counterparts. This paper looks in detail at the end of the deltaic sedimentation in the Pliocene deltas of the Amur River on the island of Sakhalin, and the Colorado River in the Fish Creek-Vallecito Basin of southern California. In both cases the deltas are sand-rich with distant provenances in East Asia and the Colorado Plateau respectively; also they both coexist with locally derived clastic sedimentation. Despite these similarities, there are significant differences between the two deltas as a direct result of the differences in plate boundary movement rates and tectonic state. On Sakhalin, the plate boundary has moved at about 1.95 mm a-1 during the Pliocene and has been in a transpressional state. Primary deltaic sedimentation ended by a three main mechanisms: uplift of the island along the transpressional plate boundary detached the delta from the trunk stream; growth of anticlines over strands of the plate boundary disrupted the consequent delta-top drainage; and late sedimentation involved reworking of the far-travelled deltaic material. In California, where the plate boundary has moved at about 50 mm a-1 in the Pliocene, deltaic sedimentation ceased by translation of the receiving basin from the river mouth. New field and mineralogical data suggest that Colorado River sedimentation waned over a period of about 1 Ma in the Late Pliocene, and was gradually overwhelmed by locally

  3. Deccan Volcanism, Chicxulub Impact, Climate Change and the end-Cretaceous Mass Extinction

    NASA Astrophysics Data System (ADS)

    Keller, Gerta; Punekar, Jahnavi; Mateo, Paula; Adatte, Thierry; Spangenberg, Jorge

    2015-04-01

    Age control for Deccan volcanism, associated global climate changes, high-stress conditions and the KTB mass extinction is excellent based on biostratigraphy and corroborated by new U-Pb dating providing new evidence for a complex mass extinction scenario. The massive Deccan eruptions of phase-2 began in the latest Maastrichtian C29r and ended at or near the Cretaceous-Tertiary boundary (KTB) depositing ~3000 m of stacked lava flows or 80% of the total Deccan eruptions over a period of just 250 ky. The onset of phase-2 eruptions coincided with rapid global warming on land (8°C) and oceans (4°C) and increasingly high-stress environments evident by dwarfed species and decreased diversity preceding the mass extinction in planktic foraminiferal zones CF2-CF1. Deep cores in the Krishna-Godavari Basin, SE India, document the rapid mass extinction of planktic foraminifera in intertrappean sediments between four major volcanic eruptions known as the longest lava flows on Earth. Maximum stress is observed globally approaching the end of the Maastrichtian with faunal assemblages dominated (~90%) by the disaster opportunist Guembelitria cretacea. This interval correlates with the massive eruptions of the world's longest lava flows, renewed rapid global warming and ocean acidification during the last ~50 ky of the Maastrichtian. The Chicxulub impact occurred during the global warming near the base of zone CF1 preceding the mass extinction by <100 ky (depending on the time scale used). This age estimate is based on the stratigraphically oldest impact spherule layer in NE Mexico, Texas, and Yucatan crater core Yaxcopoil-1. In all other regions (e.g., North Atlantic, Caribbean, Belize, Guatemala, southern Mexico) impact spherules are reworked in early Danian sediments (zone P1a) at least 100 ky after the KTB due to Gulf Stream erosion and increased tectonic activity in the region. No species extinctions are associated with the Chicxulub impact. Any KTB mass extinction scenario

  4. Gulf War Illness: Challenges Persist.

    PubMed

    Nettleman, Mary

    2015-01-01

    It has been more than 20 years since the United States and coalition forces entered Kuwait and Iraq. Actual combat was of remarkably short duration: less than 1 week of sustained ground activity and 6 weeks of air missions. Thus, it was surprising when approximately 200,000 returning US veterans were affected by a chronic multi-symptom illness that came to be known as Gulf War Illness (GWI). There were many challenges in investigating GWI, not least of which was that it took several years before the condition was officially taken seriously. There were multiple exposures to potentially causal agents on and off the battlefield, but these exposures were documented incompletely if at all, leaving epidemiologists to rely on self-report for information. In the past 2 years, significant controversy has arisen over the future directions of the field. Despite these challenges, several studies have implicated exposure to acetylcholinesterase inhibitors such as pyridostigmine bromide in the genesis of the condition. The story of GWI can inform research into other conditions and guide future work on veterans' health.

  5. Electronic Eye: Streaming Video On-Demand.

    ERIC Educational Resources Information Center

    Meulen, Kathleen

    2002-01-01

    Discusses the use of on-demand streaming video in school libraries. Explains how streaming works, considers advantages and technical issues, and describes products from three companies that are pioneering streaming in the educational video market. (LRW)

  6. Pneumatic inflatable end effector

    NASA Technical Reports Server (NTRS)

    Clark, K. H.; Johnston, J. D. (Inventor)

    1981-01-01

    The invention relates to an end effector device for robot or teleoperated type space vehicle which includes an inflatable balloon member carried on the end of tubular member which has a hollow center or conduit through which a suitable pressurized fluid is supplied. The device may be inserted into a variety of shaped openings or truss-type structures for handling in space.

  7. WADEABLE STREAMS ASSESSMENT | Science Inventory ...

    EPA Pesticide Factsheets

    This Wadeable Streams Assessment (WSA) provides the first statistically defensible summary of the condition of the nation’s streams and small rivers, which are so integrally tied to our history. This report brings the results of this ground-breaking study to the American public.This assessment encompasses the wadeable streams and rivers that account for a vast majority of the length of flowing waters in the United States. To perform this assessment, EPA, the states, and tribes collected chemical, physical, and biological data at more 1,392 wadeable perennial stream locations to determine the biological condition of these waters and the most important factors affecting their water quality. Teams collected samples at sites chosen using an innovative statistical design to ensure representative results. The results of this analysis provide a clear assessment of the biological quality of wadeable, perennial streams and rivers across the country, within each of three major climatic and landform regions, and nine ecological regions. Information provided in this report fills an important gap in meeting the requirements of the CWA. The purpose of this assessment is fourfold: 1. Report on the ecological condition of all wadeable, perennial streams and rivers within the conterminous United States. (Pilot projects are underway in Alaska and Hawaii.) 2. Describe the biological condition of these systems using direct measures of aquatic life. Assessments of stream

  8. Generation of mock tidal streams

    NASA Astrophysics Data System (ADS)

    Fardal, Mark A.; Huang, Shuiyao; Weinberg, Martin D.

    2015-09-01

    In this paper, we discuss a method for the generation of mock tidal streams. Using an ensemble of simulations in an isochrone potential where the actions and frequencies are known, we derive an empirical recipe for the evolving satellite mass and the corresponding mass-loss rate, and the ejection conditions of the stream material. The resulting stream can then be quickly generated either with direct orbital integration, or by using the action-angle formalism. The model naturally produces streaky features within the stream. These are formed due to the radial oscillation of the progenitor and the bursts of stars emitted near pericentre, rather than clumping at particular oscillation phases as sometimes suggested. When detectable, these streaky features are a reliable diagnostic for the stream's direction of motion and encode other information on the progenitor and its orbit. We show several tests of the recipe in alternate potentials, including a case with a chaotic progenitor orbit which displays a marked effect on the width of the stream. Although the specific ejection recipe may need adjusting when elements such as the orbit or satellite density profile are changed significantly, our examples suggest that model tidal streams can be quickly and accurately generated by models of this general type for use in Bayesian sampling.

  9. 75 FR 49883 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Reef Fish Fishery of the Gulf of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-16

    ... Region, NMFS (RA) to re-open the Gulf of Mexico (Gulf) recreational red snapper season after the... optimum yield for the fishery, thus enhancing social and economic benefits to the fishery. DATES: Comments... 27217, May 14, 2010) to close a portion of the Gulf exclusive economic zone (EEZ) to all fishing....

  10. 75 FR 58334 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Reef Fish Fishery of the Gulf of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-24

    ... Gulf of Mexico Recreational Red Snapper Season AGENCY: National Marine Fisheries Service (NMFS.... SUMMARY: NMFS re-opens the recreational red snapper component of the reef fish fishery in the exclusive economic zone (EEZ) of the Gulf of Mexico (Gulf). NMFS previously determined the recreational red...

  11. 76 FR 54727 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Spiny Lobster Fishery of the Gulf...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-02

    ... Caribbean, Gulf of Mexico, and South Atlantic; Spiny Lobster Fishery of the Gulf of Mexico and South... Fishery Management Plan for the Spiny Lobster Fishery of the Gulf of Mexico and South Atlantic (FMP) for review, approval, and implementation by NMFS. Amendment 10 proposes actions to revise the lobster...

  12. 76 FR 22345 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Reef Fish Fishery of the Gulf of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-21

    ... to reduce overfishing of gag in the Gulf of Mexico (Gulf). This rule would reduce the commercial... reduce overfishing of the gag resource in the Gulf. DATES: Written comments must be received on or before... prevent overfishing and achieve, on a continuing basis, the optimum yield (OY) from federally managed...

  13. 76 FR 31874 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Reef Fish Fishery of the Gulf of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-02

    ..., and implements interim measures to reduce overfishing of gag in the Gulf of Mexico (Gulf). This rule... overfishing of the gag resource in the Gulf. DATES: This rule is effective June 1, 2011, through November 29... gag resource continues to be overfished and experiencing overfishing, NMFS published a...

  14. 75 FR 74650 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Reef Fish Fishery of the Gulf of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-01

    ..., Gulf of Mexico, and South Atlantic; Reef Fish Fishery of the Gulf of Mexico; Gag Grouper Management... Management Council (Council). The intended effect of this final temporary rule is to reduce overfishing of...: The reef fish fishery of the Gulf of Mexico is managed under the fishery management plan (FMP)....

  15. 78 FR 53745 - Gulf South Pipeline Company, LP; Petal Gas Storage, L.L.C.; Gulf South Pipeline Company, LP...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-30

    ... Federal Energy Regulatory Commission Gulf South Pipeline Company, LP; Petal Gas Storage, L.L.C.; Gulf... (Gulf South) and Petal Gas Storage, L.L.C. (Petal) filed jointly with the Federal Energy Regulatory Commission (Commission) an abbreviated application under section 7(b) and 7(c) of the Natural Gas Act...

  16. 76 FR 50979 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Reef Fish Fishery of the Gulf of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-17

    ... commercial sector of the reef fish fishery in the Gulf of Mexico (Gulf) exclusive economic zone (EEZ... commercial sector of the reef fish fishery in the Gulf EEZ. If implemented, this rule would implement... becomes effective on January 1, 2012. The intent of this provision was to give commercial reef...

  17. 77 FR 40561 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Reef Fish Fishery of the Gulf of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-10

    ..., Gulf of Mexico, and South Atlantic; Reef Fish Fishery of the Gulf of Mexico; Amendment 34 AGENCY... Council (Council) has submitted Amendment 34 to the Fishery Management Plan for the Reef Fish Resources of the Gulf of Mexico (FMP) for review, approval, and implementation by NMFS. Amendment 34 proposes...

  18. 76 FR 50181 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Reef Fish Fishery of the Gulf of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-12

    ... National Oceanic and Atmospheric Administration RIN 0648-XA505 Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Reef Fish Fishery of the Gulf of Mexico; Exempted Fishing Permit AGENCY: National... 50 CFR part 622, as they pertain to reef fish managed by the Gulf of Mexico Fishery...

  19. 75 FR 21512 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Reef Fish Fishery of the Gulf of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-26

    ... Caribbean, Gulf of Mexico, and South Atlantic; Reef Fish Fishery of the Gulf of Mexico; Amendment 31 AGENCY... eastern Gulf while maintaining adequate protective measures for sea turtles. DATES: This rule is effective... Act (Magnuson- Stevens Act). The taking of sea turtles is prohibited, with certain...

  20. 78 FR 32179 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Reef Fish Fishery of the Gulf of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-29

    ... (EEZ) off each Gulf state for the 2013 red snapper recreational fishing season. This final rule is...). The closure dates off each Gulf state in that emergency rule were based on the recreational quota... 2013 red snapper recreational season lengths off each Gulf state using the 2012 landings data from...

  1. 76 FR 35409 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Shrimp Fisheries of the Gulf of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-17

    ... National Oceanic and Atmospheric Administration RIN 0648-XA457 Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Shrimp Fisheries of the Gulf of Mexico and Southern Atlantic States AGENCY...: NMFS announces the receipt of an application for an exempted fishing permit (EFP) from the Gulf...

  2. Interactive real-time media streaming with reliable communication

    NASA Astrophysics Data System (ADS)

    Pan, Xunyu; Free, Kevin M.

    2014-02-01

    Streaming media is a recent technique for delivering multimedia information from a source provider to an end- user over the Internet. The major advantage of this technique is that the media player can start playing a multimedia file even before the entire file is transmitted. Most streaming media applications are currently implemented based on the client-server architecture, where a server system hosts the media file and a client system connects to this server system to download the file. Although the client-server architecture is successful in many situations, it may not be ideal to rely on such a system to provide the streaming service as users may be required to register an account using personal information in order to use the service. This is troublesome if a user wishes to watch a movie simultaneously while interacting with a friend in another part of the world over the Internet. In this paper, we describe a new real-time media streaming application implemented on a peer-to-peer (P2P) architecture in order to overcome these challenges within a mobile environment. When using the peer-to-peer architecture, streaming media is shared directly between end-users, called peers, with minimal or no reliance on a dedicated server. Based on the proposed software pɛvμa (pronounced [revma]), named for the Greek word meaning stream, we can host a media file on any computer and directly stream it to a connected partner. To accomplish this, pɛvμa utilizes the Microsoft .NET Framework and Windows Presentation Framework, which are widely available on various types of windows-compatible personal computers and mobile devices. With specially designed multi-threaded algorithms, the application can stream HD video at speeds upwards of 20 Mbps using the User Datagram Protocol (UDP). Streaming and playback are handled using synchronized threads that communicate with one another once a connection is established. Alteration of playback, such as pausing playback or tracking to a

  3. Late Quaternary rates of stream incision in Northeast Peloponnese, Greece

    NASA Astrophysics Data System (ADS)

    Karymbalis, Efthimios; Papanastassiou, Dimitrios; Gaki-Papanastassiou, Kalliopi; Ferentinou, Maria; Chalkias, Christos

    2016-09-01

    This study focuses on defining rates of fluvial incision for the last 580±5 kyr along valley systems of eight streams that drain the eastern part of the northern Peloponnese. The streams are developed on the uplifted block of the offshore-running Xylokastro normal fault, one of the main faults bounding the southern edge of the Gulf of Corinth half-graben, and have incised a set of ten uplifted marine terraces having an amphitheatric shape. These terraces range in age from 60±5 kyr to 580±5 kyr and have been mapped in detail and correlated with late Pleistocene oxygen-isotope stages of high sea-level stands by previous studies. The terraces were used in this paper as reference surfaces in order to define fluvial incision rates at the lower reaches of the studied streams. To evaluate incision rates, thirty-three topographic valley cross-sections were drawn using fieldwork measurements as well as using a highly accurate (2×2 cell size) Digital Elevation Model (DEM) at specific locations where streams cut down the inner edges of the marine terraces. For each cross-section the ratio of valley floor width to valley height (Vf) and long-term mean stream incision rates were estimated for the last 580±5 kyr, while rock uplift rates were estimated for the last 330±5 kyr. The geomorphic evolution of the valleys on the uplifted block of the Xylokastro fault has been mainly driven by the lithology of the bedrock, sea level fluctuations during the late Quaternary, and incision of the channels due to the tectonic uplift. Stream incision rates range from 0.10±0.1 mm/yr for the last 123±7 kyr to 1.14±0.1 mm/yr for the last 310±5 kyr and are gradually greater from east to west depending on the distance from the trace of the fault. Downcutting rates are comparable with the rock uplift rates, which range from 0.4±0.02 mm/yr to 1.49±0.12 mm/yr, over the last 330±5 kyr.

  4. The effect of seasonal changes on the selection of biocide inhibitors for Arabian Gulf seawater for water injection purposes

    SciTech Connect

    Al-Hashem, A.; Salman, M.; Al-Muhanna, K.; Al-Bazzaz, W.

    1997-08-01

    This investigation was carried out to determine the most effective biocide inhibitor for Northern Arabian Gulf Seawater. This seawater will be used for water injection purposes for some oil fields in Kuwait. Arabian Gulf Seawater is known to be very saline during the summer months and less saline during the rainy season of spring. The biocide inhibitors were tested in a rig with six side streams biofouling monitoring tubes (SBMT). Bacterial nutrients were added to the system and carbon steel studs were placed along the tubes of the biocide evaluation test rig (BETR). After a month, a thin, slimy, and black deposit was formed on the carbon steel studs. The deposit contained 107 general aerobic bacteria (GAB), 107 general anaerobic bacteria (GAnB) and 105 sulfate reducing bacteria (SRB). The most effective biocide inhibitor was found to be a fatty amine aryl quaternary inhibitor at 50% dosage.

  5. Deep Eddies in the Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Furey, H. H.; Bower, A. S.; Perez-Brunius, P.; Hamilton, P.

    2014-12-01

    A major Lagrangian program is currently underway to map the deep (1500-2500 m) circulation of the entire Gulf of Mexico. Beginning in 2011, more than 120 acoustically tracked RAFOS floats have been released in the eastern, central and western Gulf, many in pairs and triplets. Most floats are programmed to drift for two years, obtaining position fixes and temperature/pressure measurements three times daily. More than 80 floats have completed their missions, and results from the trajectories will be described with a focus on mesoscale eddying behavior. In particular, the first-ever observations of deep energetic anticyclonic eddies (possibly lenses) forming at and separating from a northeastward-flowing boundary current west of Campeche Bank will be discussed. The existence of these eddies has major implications for exchange between the continental slope and interior Gulf. The project is being supported by the U.S. Bureau of Ocean Energy Management (BOEM).

  6. Tempo of gulf activity brightens outlook

    SciTech Connect

    Hagar, R. )

    1989-12-01

    Operators, mainly on the basis of oil and natural gas price expectations, plan to steadily boost their exploration and development work in the Gulf of Mexico. The increase in activity, however, isn't yet reflected in the gulf's rig count. An active rig tally shows the October average to be the second lowest for all the Octobers in the 1980s. Only during October 1986 were there fewer rigs working in the gulf during that month this decade. On an annual basis, however, the monthly active rig count in 1989 is higher than in 1986 and 1987, but short of 1988's average and less than one half the level recorded inn the peak year of 1981. The author discusses signs that activity is rebounding.

  7. The Stream-Catchment (StreamCat) Dataset

    EPA Science Inventory

    Stream environments reflect, in part, the hydrologic integration of upstream landscapes. Characterizing upstream landscape features is critical for effectively understanding, managing, and conserving riverine ecosystems. However, watershed delineation is a major challenge if hund...

  8. Experimental and numerical investigation of Acoustic streaming (Eckart streaming)

    NASA Astrophysics Data System (ADS)

    Dridi, Walid; Botton, Valery; Henry, Daniel; Ben Hadid, Hamda

    The application of sound waves in the bulk of a fluid can generate steady or quasi-steady flows reffered to as Acoustic streaming flows. We can distinguish two kind of acoustic streaming: The Rayleigh Streaming is generated when a standing acoustic waves interfere with solid walls to give birth to an acoustic boundary layer. Steady recirculations are then driven out of the boundary layer and can be used in micro-gravity, where the free convection is too weak or absent, to enhance the convective heat or mass transfer and cooling the electronic devises [1]. The second kind is the Eckart streaming, which is a flow generated far from the solid boundaries, it can be used to mix a chemical solutions [2], and to drive a viscous liquids in channels [3-4], in micro-gravity area. Our study focuses on the Eckart streaming configuration, which is investigated both numerical and experimental means. The experimental configuration is restricted to the case of a cylindrical non-heated cavity full of water or of a water+glycerol mixture. At the middle of one side of the cavity, a plane ultrasonic transducer generates a 2MHz wave; an absorber is set at the opposite side of the cavity to avoid any reflections. The velocity field is measured with a standard PIV system. [1] P. Vainshtein, M. Fichman and C. Gutfinger, "Acoustic enhancement of heat transfer between two parallel plates", International Journal of Heat and Mass Transfert, 1995, 38(10), 1893. [2] C. Suri, K. Tekenaka, H. Yanagida, Y. Kojima and K. Koyama, "Chaotic mixing generated by acoustic streaming", Ultrasonics, 2002, 40, 393 [3] O.V. Rudenko and A.A. Sukhorukov, "Nonstationnary Eckart streaming and pumping of liquid in ultrasonic field", Acoustical Physics, 1998, 44, 653. [4] Kenneth D. Frampton, Shawn E. Martin and Keith Minor, "The scaling of acoustic streaming for application in micro-fluidic devices", Applied Acoustics, 2003, 64,681

  9. Geophysical observations on northern part of Georges Bank and adjacent basins of Gulf of Maine

    USGS Publications Warehouse

    Oldale, R.N.; Hathaway, J.C.; Dillon, William P.; Hendricks, J.D.; Robb, James M.

    1974-01-01

    Continuous-seismic-reflection and magnetic-intensity profiles provide data for inferences about the geology of the northern part of Georges Bank and the basins of the Gulf of Maine adjacent to the bank. Basement is inferred to be mostly sedimentary and volcanic rocks of Paleozoic age that were metamorphosed and intruded locally by felsic and mafic plutons near the end of the Paleozoic Era. During Late Triassic time, large fault basins formed within the Gulf of Maine and probably beneath Georges Bank. The fault basins and a possible major northeast-trending fault zone beneath the northern part of the bank probably formed as a result of the opening Atlantic during the Mesozoic. Nonmarine sediments, associated with mafic flows and intrusive rocks, were deposited in the fault basins as they formed. The upper surface of the Triassic and pre-Triassic rocks that comprise basement is an unconformity that makes up much of the bottom of the Gulf of Maine. Depth to the basement surface beneath the gulf differ greatly because of fluvial erosion in Tertiary time and glacial erosion in Pleistocene time. Beneath the northern part of Georges Bank the basement surface is smoother and slopes southward. Prominent valleys, cut before Late Cretaceous time, are present beneath this part of the bank. Cretaceous, Tertiary, and possibly Jurassic times were characterized by episodes of coastal-plain deposition and fluvial erosion. During this time a very thick wedge of sediment, mostly of Jurassic(?) and Cretaceous ages, was deposited on the shelf. Major periods of erosion took place at the close of the Cretaceous and during the Pliocene. Fluvial erosion during the Pliocene removed much of the coastal-plain sedimentary wedge and formed the Gulf of Maine. Pleistocene glaciers eroded all but a few remnants of the coastal-plain sediments within the gulf and deposited a thick section of drift against the north slope of Georges Bank and a thin veneer of outwash on the bank. Marine sediments were

  10. Alpha-Stream Convertor

    NASA Technical Reports Server (NTRS)

    Dyson, Jr., Rodger William (Inventor); Bruder, Geoffrey Adam (Inventor)

    2015-01-01

    A thermo-acoustic engine and/or cooler is provided and includes an elongated tubular body, multiple regenerators disposed within the body, multiple heat exchangers disposed within the body, where at least one heat exchanger is disposed adjacent to each of the multiple regenerators, multiple transducers axially disposed at each end of the body, and an acoustic wave source generating acoustic waves. At least one of the acoustic waves is amplified by one of the regenerators and at least another acoustic wave is amplified by a second one of regenerators.

  11. Venezuela positioning itself to take key market role in wake of Gulf War

    SciTech Connect

    Not Available

    1991-08-19

    This paper reports on Venezuela which continues efforts to position itself in world markets to capitalize on fallout from the Persian Gulf war. The central government and state oil company Petroleos de Venezuela SA have accelerated already ambitious plans to expand activities in upstream and downstream oil and gas sectors. Pvdsa has sharply increased its 1991-96 investment program from the level planned at the end of last year. The goal is to put Venezuela on a par with major Persian Gulf oil exporters in terms of productive capacity. Linchpin of those efforts could well be further steps toward privatization of Venezuela's oil sector. For the first time since nationalization in 1976, private foreign and domestic companies are being permitted to participate in Venezuelan exploration and development. In addition, the government is trimming the onerous tax burden the oil sector has carried in Venezuela, as well as its heavy subsidy of domestic petroleum products.

  12. River network routing in all rivers of the Texas Gulf

    NASA Astrophysics Data System (ADS)

    David, C. H.; Maidment, D. R.; Hong, S.; Niu, G.; Yang, Z.

    2009-12-01

    The mapped rivers and streams of the contiguous United States are available in a high resolution geographic information system (GIS) dataset called NHDPlus. This hydrographic dataset has about 3 million river and water body reaches along with information on how they are connected into networks. A river network model called RAPID is developed for the NHDPlus river network and applied to the 68,143 river reaches of the entire Texas Gulf, whose lateral inflow to the river network is calculated by a land surface model. RAPID allows for a matrix-based calculation of flow and volume of water in all reaches of a river network, with many thousands of reaches. Gages from the USGS National Water Information System are used to assess the quality of model calculations and to automatically determine optimal model parameters with about 1 gage available for each 160 reaches simulated. RAPID is adapted for parallel computing and has been tested on the Lonestar supercomputer (http://www.tacc.utexas.edu/resources/hpcsystems/) although challenges related to parallel computing are significant. The first author was awarded the 2008 Horton (Hydrology) Research Grant for this work.

  13. Mesoscale eddies in the Gulf of Alaska: Observations and implications

    NASA Astrophysics Data System (ADS)

    Rovegno, Peter

    Mesoscale eddies in the Gulf of Alaska are thought to contribute to the shelf-slope exchange of nutrients and plankton, enhancing biological production. We report on a study of two anticyclonic mesoscale eddies in this region observed through in situ sampling during August and September 2007. Both eddies exhibited in their cores theta-S profiles with warmer, fresher water relative to the properties of the ambient basin water between 150 and 300 m depth. Hydrographic properties and satellite altimetry data were analyzed to identify likely formation regions for each feature. One eddy, sampled near Yakutat, Alaska, originated in the Sitka formation region (221-223° E); the second eddy, sampled south of Kodiak Island, originated near the Kenai Peninsula, southeast of the Kennedy and Stevenson entrances to Cook Inlet—an area not previously studied as a formation region. Subsequent analysis of 16 years of satellite altimeter data (from 1992 to 2008) with an algorithm designed to identify and track eddies revealed approximately 6 Kenai eddies that have formed in this region. Although this number constitutes only 3.2% of the 188 eddies identified by the algorithm during this period, it represents 15.4% of the 39 eddies that formed in or propagated westward into the Alaskan Stream.

  14. Conservation in the Arabian Gulf countries

    SciTech Connect

    Akkad, A.A.

    1990-05-01

    In the Arabian Gulf region in general, and in Saudi Arabia in particular, demand for water in the agricultural, domestic, and industrial sectors has increased dramatically as a result of rapid development, and improved standard of living, and diversification of economic activity in agriculture and industry. This article presents an overview of supply and demand situations prevailing in the Arabian Gulf region and discusses various conventional and unconventional alternatives for meeting the growing demand for water. It also describes conservation measures and their socioeconomic effects.

  15. Star formation in the "Gulf of Mexico"

    NASA Astrophysics Data System (ADS)

    Armond, T.; Reipurth, B.; Bally, J.; Aspin, C.

    2011-04-01

    We present an optical/infrared study of the dense molecular cloud, L935, dubbed "The Gulf of Mexico", which separates the North America and the Pelican nebulae, and we demonstrate that this area is a very active star forming region. A wide-field imaging study with interference filters has revealed 35 new Herbig-Haro objects in the Gulf of Mexico. A grism survey has identified 41 Hα emission-line stars, 30 of them new. A small cluster of partly embedded pre-main sequence stars is located around the known LkHα 185-189 group of stars, which includes the recently erupting FUor HBC 722.

  16. Shelf Circulation in the Gulf of Mexico.

    DTIC Science & Technology

    2007-11-02

    Gulf of Mexico between 1990 and 1993, are used to describe the seasonal fluctuations in patterns of atmospheric variables from a contemporary set of measurements. Seasonal maps of wind stress based on these measurements resemble wind stress maps based on ship observations, as published by Elliot (1979), rather than maps based on analyses of numerical weather forecasts, as published by Rhodes et a. (1989), particularly near the western boundary of the Gulf. Seasonal maps of wind stress curl are characterized by positive curls over the western and southwestern

  17. Gulf Coast Clean Energy Application Center

    SciTech Connect

    Dillingham, Gavin

    2013-09-30

    The Gulf Coast Clean Energy Application Center was initiated to significantly improve market and regulatory conditions for the implementation of combined heat and power technologies. The GC CEAC was responsible for the development of CHP in Texas, Louisiana and Oklahoma. Through this program we employed a variety of outreach and education techniques, developed and deployed assessment tools and conducted market assessments. These efforts resulted in the growth of the combined heat and power market in the Gulf Coast region with a realization of more efficient energy generation, reduced emissions and a more resilient infrastructure. Specific t research, we did not formally investigate any techniques with any formal research design or methodology.

  18. TROPOMI end-to-end performance studies

    NASA Astrophysics Data System (ADS)

    Voors, Robert; de Vries, Johan; Veefkind, Pepijn; Gloudemans, Annemieke; Mika, Àgnes; Levelt, Pieternel

    2008-10-01

    The TROPOspheric Monitoring Instrument (TROPOMI) is a UV/VIS/NIR/SWIR non-scanning nadir viewing imaging spectrometer that combines a wide swath (110°) with high spatial resolution (8 x 8 km). Its main heritages are from the Ozone Monitoring Instrument (OMI) and from SCIAMACHY. Since its launch in 2004 OMI has been providing, on a daily basis and on a global scale, a wealth of data on ozone, NO2 and minor trace gases, aerosols and local pollution, a scanning spectrometer launched in 2004. The TROPOMI UV/VIS/NIR and SWIR heritage is a combination of OMI and SCIAMACHY. In the framework of development programs for a follow-up mission for the successful Ozone Monitoring Instrument, we have developed the so-called TROPOMI Integrated Development Environment. This is a GRID based software simulation tool for OMI follow-up missions. It includes scene generation, an instrument simulator, a level 0-1b processing chain, as well as several level 1b-2 processing chains. In addition it contains an error-analyzer, i.e. a tool to feedback the level 2 results to the input of the scene generator. The paper gives a description of the TROPOMI instrument and focuses on design aspects as well as on the performance, as tested in the end-to-end development environment TIDE.

  19. The end of the end of ideology.

    PubMed

    Jost, John T

    2006-10-01

    The "end of ideology" was declared by social scientists in the aftermath of World War II. They argued that (a) ordinary citizens' political attitudes lack the kind of stability, consistency, and constraint that ideology requires; (b) ideological constructs such as liberalism and conservatism lack motivational potency and behavioral significance; (c) there are no major differences in content (or substance) between liberal and conservative points of view; and (d) there are few important differences in psychological processes (or styles) that underlie liberal versus conservative orientations. The end-of-ideologists were so influential that researchers ignored the topic of ideology for many years. However, current political realities, recent data from the American National Election Studies, and results from an emerging psychological paradigm provide strong grounds for returning to the study of ideology. Studies reveal that there are indeed meaningful political and psychological differences that covary with ideological self-placement. Situational variables--including system threat and mortality salience--and dispositional variables--including openness and conscientiousness--affect the degree to which an individual is drawn to liberal versus conservative leaders, parties, and opinions. A psychological analysis is also useful for understanding the political divide between "red states" and "blue states."

  20. Wetlands of the Gulf Coast

    NASA Technical Reports Server (NTRS)

    2001-01-01

    This set of images from the Multi-angle Imaging SpectroRadiometer highlights coastal areas of four states along the Gulf of Mexico: Louisiana, Mississippi, Alabama and part of the Florida panhandle. The images were acquired on October 15, 2001 (Terra orbit 9718)and represent an area of 345 kilometers x 315 kilometers.

    The two smaller images on the right are (top) a natural color view comprised of red, green, and blue band data from MISR's nadir(vertical-viewing) camera, and (bottom) a false-color view comprised of near-infrared, red, and blue band data from the same camera. The predominantly red color of the false-color image is due to the presence of vegetation, which is bright at near-infrared wavelengths. Cities appear as grey patches, with New Orleans visible at the southern edge of Lake Pontchartrain, along the left-hand side of the images. The Lake Pontchartrain Bridge runs approximately north-south across the middle of the lake. The distinctive shape of the Mississippi River Delta can be seen to the southeast of New Orleans. Other coastal cities are visible east of the Mississippi, including Biloxi, Mobile and Pensacola.

    The large image is similar to the true-color nadir view, except that red band data from the 60-degree backward-looking camera has been substituted into the red channel; the blue and green data from the nadir camera have been preserved. In this visualization, green hues appear somewhat subdued, and a number of areas with a reddish color are present, particularly near the mouths of the Mississippi, Pascagoula, Mobile-Tensaw, and Escambia Rivers. Here, the red color is highlighting differences in surface texture. This combination of angular and spectral information differentiates areas with aquatic vegetation associated with poorly drained bottom lands, marshes, and/or estuaries from the surrounding surface vegetation. These wetland regions are not as well differentiated in the conventional nadir views.

    Variations in ocean color

  1. Regional characteristics of extreme drought patterns in stream flow records

    NASA Astrophysics Data System (ADS)

    Nasrollahi, N.; Ahmadi, M.; Alaeipour, A.

    2010-12-01

    Global warming has shown dramatic effects on natural systems in some parts of the world. Middle East is one of the locations that is affected by the severe changes in the climate conditions. In this study, the regional characteristics of severe seasonal droughts have been studied by analyzing the extreme value properties of the annual maximum series of river stream flows in the last 30 years. The study region is Karun River located in south western Iran. Karun River is Iran's most effluent, and the only navigable river which is 720 km long. It rises in the Zard Kuh Mountains and continues toward the Persian Gulf. There are a number of dams on the Karun River, with the purpose of generating hydroelectric power and flood control. The area is divided into 10 catchments with daily stream flow records. To investigate the drought periods, the threshold level is defined by percentiles from the flow duration curve. Two different regionalization tools are compared, L-moment diagrams and empirical orthogonal functions. The L-moment and EOF diagrams provided virtually the same conclusions with regard to clustering of catchments, and large scale trends were found in the data which confirms a regional pattern.

  2. Mixing of Supersonic Streams

    NASA Technical Reports Server (NTRS)

    Hawk, C. W.; Landrum, D. B.; Muller, S.; Turner, M.; Parkinson, D.

    1998-01-01

    The Strutjet approach to Rocket Based Combined Cycle (RBCC) propulsion depends upon fuel-rich flows from the rocket nozzles and turbine exhaust products mixing with the ingested air for successful operation in the ramjet and scramjet modes. It is desirable to delay this mixing process in the air-augmented mode of operation present during low speed flight. A model of the Strutjet device has been built and is undergoing test to investigate the mixing of the streams as a function of distance from the Strutjet exit plane during simulated low speed flight conditions. Cold flow testing of a 1/6 scale Strutjet model is underway and nearing completion. Planar Laser Induced Fluorescence (PLIF) diagnostic methods are being employed to observe the mixing of the turbine exhaust gas with the gases from both the primary rockets and the ingested air simulating low speed, air augmented operation of the RBCC. The ratio of the pressure in the turbine exhaust duct to that in the rocket nozzle wall at the point of their intersection is the independent variable in these experiments. Tests were accomplished at values of 1.0, 1.5 and 2.0 for this parameter. Qualitative results illustrate the development of the mixing zone from the exit plane of the model to a distance of about 10 rocket nozzle exit diameters downstream. These data show the mixing to be confined in the vertical plane for all cases, The lateral expansion is more pronounced at a pressure ratio of 1.0 and suggests that mixing with the ingested flow would be likely beginning at a distance of 7 nozzle exit diameters downstream of the nozzle exit plane.

  3. Mixing of Supersonic Streams

    NASA Technical Reports Server (NTRS)

    Hawk, C. W.; Landrum, D. B.; Muller, S.; Turner, M.; Parkinson, D.

    1998-01-01

    The Strutjet approach to Rocket Based Combined Cycle (RBCC) propulsion depends upon fuel-rich flows from the rocket nozzles and turbine exhaust products mixing with the ingested air for successful operation in the ramjet and scramjet modes. It is desirable to delay this mixing process in the air-augmented mode of operation present during low speed flight. A model of the Strutjet device has been built and is undergoing test to investigate the mixing of the streams as a function of distance from the Strutjet exit plane during simulated low speed flight conditions. Cold flow testing of a 1/6 scale Strutjet model is underway and nearing completion. Planar Laser Induced Fluorescence (PLIF) diagnostic methods are being employed to observe the mixing of the turbine exhaust gas with the gases from both the primary rockets and the ingested air simulating low speed, air augmented operation of the RBCC. The ratio of the pressure in the turbine exhaust duct to that in the rocket nozzle wall at the point of their intersection is the independent variable in these experiments. Tests were accomplished at values of 1.0, 1.5 and 2.0 for this parameter. Qualitative results illustrate the development of the mixing zone from the exit plane of the model to a distance of about 19 equivalent rocket nozzle exit diameters downstream. These data show the mixing to be confined in the vertical plane for all cases, The lateral expansion is more pronounced at a pressure ratio of 1.0 and suggests that mixing with the ingested flow would be likely beginning at a distance of 7 nozzle exit diameters downstream of the nozzle exit plane.

  4. National Rivers and Streams Assessment

    EPA Pesticide Factsheets

    The NRSA is a collaborative, statistical survey of the nation's rivers and streams. It is one of four national surveys that EPA and its partners conduct to assess the condition and health of the nation's water resources.

  5. ATLAS Live: Collaborative Information Streams

    NASA Astrophysics Data System (ADS)

    Goldfarb, Steven; ATLAS Collaboration

    2011-12-01

    I report on a pilot project launched in 2010 focusing on facilitating communication and information exchange within the ATLAS Collaboration, through the combination of digital signage software and webcasting. The project, called ATLAS Live, implements video streams of information, ranging from detailed detector and data status to educational and outreach material. The content, including text, images, video and audio, is collected, visualised and scheduled using digital signage software. The system is robust and flexible, utilizing scripts to input data from remote sources, such as the CERN Document Server, Indico, or any available URL, and to integrate these sources into professional-quality streams, including text scrolling, transition effects, inter and intra-screen divisibility. Information is published via the encoding and webcasting of standard video streams, viewable on all common platforms, using a web browser or other common video tool. Authorisation is enforced at the level of the streaming and at the web portals, using the CERN SSO system.

  6. Video streaming into the mainstream.

    PubMed

    Garrison, W

    2001-12-01

    Changes in Internet technology are making possible the delivery of a richer mixture of media through data streaming. High-quality, dynamic content, such as video and audio, can be incorporated into Websites simply, flexibly and interactively. Technologies such as G3 mobile communication, ADSL, cable and satellites enable new ways of delivering medical services, information and learning. Systems such as Quicktime, Windows Media and Real Video provide reliable data streams as video-on-demand and users can tailor the experience to their own interests. The Learning Development Centre at the University of Portsmouth have used streaming technologies together with e-learning tools such as dynamic HTML, Flash, 3D objects and online assessment successfully to deliver on-line course content in economics and earth science. The Lifesign project--to develop, catalogue and stream health sciences media for teaching--is described and future medical applications are discussed.

  7. Streaming in English Primary Schools

    ERIC Educational Resources Information Center

    Acland, H.

    1973-01-01

    This paper seeks to extend our knowledge of ability grouping through the reanalysis of two sets of survey data, the Plowden survey (Peaker, 1967) and the NFER streaming survey (Barker Lunn, 1970). (Editor)

  8. MVSP: multithreaded VLIW stream processor

    NASA Astrophysics Data System (ADS)

    Sardashti, Somayeh; Ghasemi, Hamid Reza; Fatemi, Omid

    2006-02-01

    Stream processing is a new trend in computer architecture design which fills the gap between inflexible special-purpose media architectures and programmable architectures with low computational ability for media processing. Stream processors are designed for computationally intensive media applications characterized by high data parallelism and producer-consumer locality with little global data reuse. In this paper, we propose a new stream processor, named MVSP1. This processor is a programmable stream processor based on Imagine [1]. MVSP exploits TLP2, DLP 3, SP 4 and ILP 5 parallelisms inherent in media applications. Full simulator of MVSP has been implemented and several media workloads composed of EEMBC [2] benchmarks have been applied. The simulation results show the performance and functional unit utilization improvements of more than two times in comparison with Imagine processor.

  9. Cellular Subcompartments through Cytoplasmic Streaming.

    PubMed

    Pieuchot, Laurent; Lai, Julian; Loh, Rachel Ann; Leong, Fong Yew; Chiam, Keng-Hwee; Stajich, Jason; Jedd, Gregory

    2015-08-24

    Cytoplasmic streaming occurs in diverse cell types, where it generally serves a transport function. Here, we examine streaming in multicellular fungal hyphae and identify an additional function wherein regimented streaming forms distinct cytoplasmic subcompartments. In the hypha, cytoplasm flows directionally from cell to cell through septal pores. Using live-cell imaging and computer simulations, we identify a flow pattern that produces vortices (eddies) on the upstream side of the septum. Nuclei can be immobilized in these microfluidic eddies, where they form multinucleate aggregates and accumulate foci of the HDA-2 histone deacetylase-associated factor, SPA-19. Pores experiencing flow degenerate in the absence of SPA-19, suggesting that eddy-trapped nuclei function to reinforce the septum. Together, our data show that eddies comprise a subcellular niche favoring nuclear differentiation and that subcompartments can be self-organized as a consequence of regimented cytoplasmic streaming.

  10. MODELING PLUMES IN SMALL STREAMS

    EPA Science Inventory

    Pesticides accumulate on land surfaces from agricultural, commercial, and domestic application, and wash into streams and rivers during dry and wet weather. Flood water retention basins or structures often collect this contaminated runoff, providing intermediate storage and limit...

  11. Stream Mitigation Protocol Compendium - 2004

    EPA Pesticide Factsheets

    This document is intended as a reference in order to select, adapt, or devise stream assessment methods appropriate for impact assessment and mitigation of fluvial resources in the CWA Section 404 Program.

  12. Semantic Complex Event Processing over End-to-End Data Flows

    SciTech Connect

    Zhou, Qunzhi; Simmhan, Yogesh; Prasanna, Viktor K.

    2012-04-01

    Emerging Complex Event Processing (CEP) applications in cyber physical systems like SmartPower Grids present novel challenges for end-to-end analysis over events, flowing from heterogeneous information sources to persistent knowledge repositories. CEP for these applications must support two distinctive features - easy specification patterns over diverse information streams, and integrated pattern detection over realtime and historical events. Existing work on CEP has been limited to relational query patterns, and engines that match events arriving after the query has been registered. We propose SCEPter, a semantic complex event processing framework which uniformly processes queries over continuous and archived events. SCEPteris built around an existing CEP engine with innovative support for semantic event pattern specification and allows their seamless detection over past, present and future events. Specifically, we describe a unified semantic query model that can operate over data flowing through event streams to event repositories. Compile-time and runtime semantic patterns are distinguished and addressed separately for efficiency. Query rewriting is examined and analyzed in the context of temporal boundaries that exist between event streams and their repository to avoid duplicate or missing results. The design and prototype implementation of SCEPterare analyzed using latency and throughput metrics for scenarios from the Smart Grid domain.

  13. End-effector microprocessor

    NASA Technical Reports Server (NTRS)

    Doggett, William R.

    1992-01-01

    The topics are presented in viewgraph form and include: automated structures assembly facility current control hierarchy; automated structures assembly facility purposed control hierarchy; end-effector software state transition diagram; block diagram for ideal install composite; and conclusions.

  14. End of Life Issues

    MedlinePlus

    ... difficult. But by deciding what end-of-life care best suits your needs when you are healthy, ... making choices about the following: The goals of care (for example, whether to use certain medicines during ...

  15. End of Life Care

    MedlinePlus

    ... this with your healthcare provider. End of Life Considerations There are situations that ill older adults may ... is not indicated. In some settings, however, the law may require that physicians offer the option of ...

  16. Brain Immune Interactions as the Basis of Gulf War Illness: Gulf War Illness Consortium (GWIC)

    DTIC Science & Technology

    2015-10-01

    Rivest, S. (2009). Regulation of innate immune responses in the brain. Nature Reviews. Immunology , 9(6), 429-439. doi:10.1038/nri2565 40 13. Sullivan K...15. SUBJECT TERMS- Gulf War Illness, consortium, CNS, innate immunity, cytokines, MRI neuroimaging, cognitive deficits, pesticides, DFP, sarin 16...researchers in the 10 funded sub-studies. 2. KEYWORDS: Provide a brief list of keywords (limit to 20 words). Gulf War Illness, consortium, CNS, innate

  17. Analysis of stream-aquifer relationships: A comparison between mass balance and Darcy's law approaches

    NASA Astrophysics Data System (ADS)

    Menció, Anna; Galán, Marta; Boix, Dani; Mas-Pla, Josep

    2014-09-01

    In Mediterranean areas, groundwater contributions are fundamental to maintain stream flow, especially during dry periods. Since groundwater withdrawal may affect stream discharge, understanding the hydraulic connectivity between streams and aquifers is critical to preserve stream runoff. However, assessing stream-aquifer interactions is often complex, due to spatial and temporal heterogeneities and the effect of diverse human pressures on the river system. Potential methods used to estimate this interaction work at different scales. All of them, however, offer complementary results which, in some cases, are difficult to integrate in a conceptual model for the stream hydrological dynamics that becomes useful to assess future water resources management actions. In this study we compare different Darcy's law and mass balance methodologies to analyze their effectiveness in determining these relationships: piezometers drilled in the stream bed were used to qualitatively describe the stream-aquifer relationship and potentiometric maps at small and large scales, respectively; the incremental flow methodology and end member mixing analysis quantified the magnitude and the proportion of surface water, waste water and groundwater contributions to the stream flow; and hydrochemical analysis using Piper diagrams, Cl-/Br- ratios, and δ18O and δ2D identified the main origin of stream water. Finally, principal component analysis satisfactorily describes the hydrogeochemical processes occurring in the stream and aquifer interface and it can be used as a valid approach to support estimations derived from the above mentioned procedures. Different seasonal behaviors, including the effect of bank storage in the stream runoff, could be only recognized by the comprehensive use of all these methods. In this sense, this paper illustrates the need of combining distinct methodologies to achieve an appropriate knowledge on the stream-aquifer interaction.

  18. The Northeast Stream Quality Assessment

    USGS Publications Warehouse

    Van Metre, Peter C.; Riva-Murray, Karen; Coles, James F.

    2016-04-22

    In 2016, the U.S. Geological Survey (USGS) National Water-Quality Assessment (NAWQA) is assessing stream quality in the northeastern United States. The goal of the Northeast Stream Quality Assessment (NESQA) is to assess the quality of streams in the region by characterizing multiple water-quality factors that are stressors to aquatic life and evaluating the relation between these stressors and biological communities. The focus of NESQA in 2016 will be on the effects of urbanization and agriculture on stream quality in all or parts of eight states: Connecticut, Massachusetts, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, and Vermont.Findings will provide the public and policymakers with information about the most critical factors affecting stream quality, thus providing insights about possible approaches to protect the health of streams in the region. The NESQA study will be the fourth regional study conducted as part of NAWQA and will be of similar design and scope to the first three, in the Midwest in 2013, the Southeast in 2014, and the Pacific Northwest in 2015 (http://txpub.usgs.gov/RSQA/).

  19. Lexical Influences on Auditory Streaming

    PubMed Central

    Billig, Alexander J.; Davis, Matthew H.; Deeks, John M.; Monstrey, Jolijn; Carlyon, Robert P.

    2013-01-01

    Summary Biologically salient sounds, including speech, are rarely heard in isolation. Our brains must therefore organize the input arising from multiple sources into separate “streams” and, in the case of speech, map the acoustic components of the target signal onto meaning. These auditory and linguistic processes have traditionally been considered to occur sequentially and are typically studied independently [1, 2]. However, evidence that streaming is modified or reset by attention [3], and that lexical knowledge can affect reports of speech sound identity [4, 5], suggests that higher-level factors may influence perceptual organization. In two experiments, listeners heard sequences of repeated words or acoustically matched nonwords. After several presentations, they reported that the initial /s/ sound in each syllable formed a separate stream; the percept then fluctuated between the streamed and fused states in a bistable manner. In addition to measuring these verbal transformations, we assessed streaming objectively by requiring listeners to detect occasional targets—syllables containing a gap after the initial /s/. Performance was better when streaming caused the syllables preceding the target to transform from words into nonwords, rather than from nonwords into words. Our results show that auditory stream formation is influenced not only by the acoustic properties of speech sounds, but also by higher-level processes involved in recognizing familiar words. PMID:23891107

  20. Stream Segment Temperature Model (SSTEMP) Version 2.0

    USGS Publications Warehouse

    Bartholow, John

    2002-01-01

    SSTEMP is a much-scaled down version of the Stream Network Temperature Model (SNTEMP) by Theurer et al. (1984). SSTEMP may be used to evaluate alternative reservoir release proposals, analyze the effects of changing riparian shade or the physical features of a stream, and examine the effects of different stream withdrawals and returns on instream temperature. Unlike the large network model, SNTEMP, this program handles only single stream segments for a single time period (e.g., month, week, day) for any given “run”. Initially designed as a training tool, SSTEMP may be used satisfactorily for a variety of simple cases that one might face on a day-to-day basis. It is especially useful to perform sensitivity and uncertainty analysis. The program requires inputs describing the average stream geometry, as well as (steady-state) hydrology and meteorology, and stream shading. SSTEMP optionally estimates the combined topographic and vegetative shade as well as solar radiation penetrating the water. It then predicts the mean daily water temperatures at specified distances downstream. It also estimates the daily maximum and minimum temperatures, and unlike SNTEMP, handles the special case of a dam with steady-state release at the upstream end of the segment. With good quality input data, SSTEMP should faithfully reproduce mean daily water temperatures throughout a stream reach. If it does not, there is a research opportunity to explain why not. One should not expect too much from SSTEMP if the input values are of poor quality or if the modeler has not adhered to the model’s assumptions.

  1. Wood in New Zealand's Native Forest Streams. Recent Advances

    NASA Astrophysics Data System (ADS)

    Mark, M. A.; Davies-Colley, R.

    2005-05-01

    We conducted a series of research projects to investigate the importance of wood in native forested streams of New Zealand. We examined abundance and geomorphic role of wood in 18 pristine native forest streams (channel width: 3-6 m) throughout New Zealand. Forest type and geographic location had no discernable influence on wood abundance, possibly reflecting the confounding influences of local features (e.g., tree fall regime) and methodology (`snap-shot' survey of a dynamic system). Number (18-66 per 100 m) and dead wood volume (85-470 m3 ha-1) of stream logs were at the high end of the international range. Living trees contributed up to 25% of total wood, and tree ferns were strongly represented (up to 11% of volume). The largest 10% of pieces contributed 75% of the total volume. The importance of the large wood pieces (>10 m3) was explored further with surveys within that watershed containing the site with the greatest wood volume. The largest pieces were rare but seemed relatively uniformly distributed. To explore the biological consequences of stream wood, we studied use of wood-related micro-habitat by the crayfish (Paranephrops planifrons White). Our findings suggest that wood is an important component of New Zealand's forested stream ecosystems.

  2. The Magellanic Stream and debris clouds

    SciTech Connect

    For, B.-Q.; Staveley-Smith, L.; Matthews, D.; McClure-Griffiths, N. M.

    2014-09-01

    We present a study of the discrete clouds and filaments in the Magellanic Stream using a new high-resolution survey of neutral hydrogen (H I) conducted with the H75 array of the Australia Telescope Compact Array, complemented by single-dish data from the Parkes Galactic All-Sky Survey. From the individual and combined data sets, we have compiled a catalog of 251 clouds and listed their basic parameters, including a morphological description useful for identifying cloud interactions. We find an unexpectedly large number of head-tail clouds in the region. The implication for the formation mechanism and evolution is discussed. The filaments appear to originate entirely from the Small Magellanic Cloud and extend into the northern end of the Magellanic Bridge.

  3. Arab-Americans and the Gulf Crisis.

    ERIC Educational Resources Information Center

    Noor Al-Deen, Hana S.

    A study examined the sentiment and impact of different types, channels, and forms of aggression against the Arab-American community during the Gulf Crisis. Data were selected from entries in the 1990 Anti-Arab Discrimination and Hate Crimes Log of the American-Arab Anti-Discrimination (ADC) National Office. Results show that there were 129 acts of…

  4. Eutrophication in the Gulf of Maine's waters

    EPA Science Inventory

    The Gulf of Maine and its watershed encompass more than 170,000 km2 and is home to over 6.5 million Canadians and Americans. Despite its long-standing importance to fisheries and natural resources and current interest in exploration of wind and tide as renewable energy sources, ...

  5. The unstable Gulf, Threats from within

    SciTech Connect

    Martin, L.G.

    1984-01-01

    Martin offers an analysis of disputes along the borders of countries in the Persian Gulf region and a description of the religious, ethnic, and ideological tensions among the peoples. The pros and cons of various options for protecting American interests are outlined. The discussion covers Iran, Iraq, Kuwait, North and South Yemen, Oman, Soudi Arabia, U.A.E., Bahrain, and Qatar.

  6. Gulf War Illness Inflammation Reduction Trial

    DTIC Science & Technology

    2015-10-01

    physical and mental functioning 2) pain , fatigue, and cognitive dysfunction 3) biomarkers of inflammation. All regulatory approvals for this...study comparing blood samples from Gulf War veterans with and without multiple symptoms of pain , fatigue, and cognitive dysfunction. The goal of the... Pain , Fatigue, Cognitive Dysfunction Accomplishments 1st Quarter  The Cooperative Research and Development Agreement (CRADA) between the Minneapolis

  7. Archaea in the Gulf of Aqaba.

    PubMed

    Ionescu, Danny; Penno, Sigrid; Haimovich, Maya; Rihtman, Branko; Goodwin, Aram; Schwartz, Daniel; Hazanov, Lena; Chernihovsky, Mark; Post, Anton F; Oren, Aharon

    2009-09-01

    Using a polyphasic approach, we examined the presence of Archaea in the Gulf of Aqaba, a warm marine ecosystem, isolated from major ocean currents and subject to pronounced seasonal changes in hydrography. Catalyzed reported deposition FISH analyses showed that Archaea make up to >20% of the prokaryotic community in the Gulf. A spatial separation between the two major phyla of Archaea was observed during summer stratification. Euryarchaeota were found exclusively in the upper 200 m, whereas Crenarchaeota were present in greater numbers in layers below the summer thermocline. 16S rRNA gene-based denaturing gradient gel electrophoresis confirmed this depth partitioning and revealed further diversity of Crenarchaeota and Euryarchaeota populations along depth profiles. Phylogenetic analysis showed pelagic Crenarchaeota and Euryarchaeota to differ from coral-associated Archaea from the Gulf, forming distinct clusters within the Marine Archaea Groups I and II. Endsequencing of fosmid libraries of environmental DNA provided a tentative identification of some members of the archaeal community and their role in the microbial community of the Gulf. Incorporation studies of radiolabeled leucine and bicarbonate in the presence of different inhibitors suggest that the archaeal community participates in autotrophic CO(2) uptake and contributes little to the heterotrophic activity.

  8. Phytoplankton bloom in Spencer Gulf, Southern Australia

    NASA Technical Reports Server (NTRS)

    2002-01-01

    South Australia occupies the center of the Australian continent. The deserts of the interior give way to more fertile land along the coast of the Southern Ocean. This true-color MODIS image from September 17, 2001, shows the marked contrast between the country's arid interior--where seasonal salt lakes stand out in white against the deserts' vast, red expanse--and the coastal regions, including Spencer Gulf, to the lower left of the image's center. The characteristic blue-green swirls of a phytoplankton bloom can be seen in the Gulf and southeastward along the coast. To Spencer Gulf's east, the brownish-gray pixels on the eastern coast of the Gulf of St. Vincent indicate the location of the city of Adelaide, the region's capital. The large dark areas that stand out amid the green vegetation do not indicate areas where vegetation had been damaged or burned. In fact, the opposite is actually true. In many cases, those areas are land protected by national and state parks and preserves, where the natural vegetation of the semi-arid landscape is allowed to exist undisturbed. For example, due east of Adelaide are Billiat Conservation Park and the semi-rectangular Murray Sunset National Park, which is across the border from South Australia in Victoria. South of those parks are the parks of the Big Desert (top) and Little Desert (bottom).

  9. Chemical oceanography of the Persian Gulf

    NASA Astrophysics Data System (ADS)

    Brewer, Peter G.; Dyrssen, D.

    Measurements of basic hydrographic properties, nutrient elements, alkalinity and total carbon dioxide were made in the Persian Gulf in February and March 1977, on R.V. Atlantis II Cruise 93. The results show clearly the penetration into the Gulf of surface Indian Ocean water, initially of 36.5% salinity which is carried northwards along the Iranian Coast, gradually increasing in salinity to more than 40%. The inflowing surface water is high in phosphate (1.0-0.5 μmoles kg -1) due to upwelling induced by the north-east monsoon. However, nitrate levels are at, or below, the detection limit and nitrogenous nutrients appear to be limiting. The seawater carbonate system is greatly perturbed by the precipitation of large quantities of calcium carbonate. The alkalinity-salinity relationship shows that the greatest carbonate loss occurs in the shallow waters of the Trucial Coast, where up to 125 μmoles kg -1 of CaCO 3 have been lost from the water. Dense, saline low specific alkalinity water formed in the shallows appears to migrate down slope to augment the outflowing waters in the deeper part of the Gulf. The outflow of the Tigris, Euphrates and Karun rivers to the north provides an intense, but low capacity signal, of low salinity, high specific alkalinity, waters. Large amounts of CO 2 are also fixed by photosynthetic processes. The classical Mediterranean type of circulation is plainly revealed. The residence time of water within the Persian Gulf is approximately 2.5 yr.

  10. GULF OF MEXICO HYPOXIA MONITORING AND MODELING

    EPA Science Inventory

    Greene, Richard M. and Russell G. Kreis. In press. Gulf of Mexico Hypoxia Monitoring and Modeling (Abstract). To be presented at the EPA Science Forum: Healthy Communities and Ecosystems, 1-3 June 2004, Washington, DC. 1 p. (ERL,GB R990).

    Oxygen-depleted or hypoxic bottom...

  11. Peace Studies, the Gulf War, and Peace.

    ERIC Educational Resources Information Center

    Stephenson, Carolyn M.

    1991-01-01

    Peace studies, as an academic discipline, dates back to the 1950s, when the field was characterized primarily by research. The 1970s brought a focus on undergraduate education. In the 1980s, a third wave brought the field into a prominence that allows it to challenge the Gulf War. (SLD)

  12. Madonnas, Whores, and the Persian Gulf War.

    ERIC Educational Resources Information Center

    Bruno, Maria F.

    1992-01-01

    Discusses reactions and attitudes of students in a women's studies course during the Gulf War. Contends that the imagery of war as a sexual, phallic event was a major topic of class discussion. Presents excerpts from teacher and student conversations. (CFR)

  13. Miscellaneous streams best management practices (BMP) report

    SciTech Connect

    Lueck, K.J., Westinghouse Hanford

    1996-07-24

    The Washington State Department of Ecology (Ecology) and U.S. Department of Energy Consent Order No. DE 91NM-177 (Consent Order) lists regulatory milestones for liquid effluent streams at the Hanford Site to comply with the permitting requirements of Washington Administrative Code (WAC) 173-216 (`State Waste Discharge Permit Program`) or WAC 173-218 (`Washington Underground Injection Control Program`) where applicable. Hanford Site liquid effluent streams discharging to the soil column are categorized as Phase I and Phase II Streams, and Miscellaneous Streams. There were originally 33 Phase I and Phase II Streams, however some of these streams have been eliminated. Miscellaneous Streams are those liquid effluent streams discharged to the ground that are not categorized as Phase I or Phase II Streams, and are subject to the requirements of several milestones identified in the Consent Order. The three criteria for identifying streams that are potentially affecting groundwater are: (1) streams discharging to surface contaminated areas (referred to as category `b` streams); (2) potentially contaminated streams (referred to as category `c` streams); and (3) streams discharging within 91 meters (300 feet) of a contaminated crib, ditch, or trench (referred to as category `d` streams). Miscellaneous Streams that meet any of these criteria must be evaluated for application of best management practices (BMP). The purpose of this report is to provide the best management practice preferred alternative. The list of BMP streams has been revised since the original submittal. Several streams from the original list of BMP streams have already been eliminated through facility upgrades, reduction of steam usage, and facility shutdowns. This document contains a description of the changes to the list of BMP streams, applicable definitions and regulatory requirements and possible alternatives, and a schedule for implementing the preferred alternatives.

  14. Unique Challenges to (Federal) Enterprise Streaming

    NASA Technical Reports Server (NTRS)

    Walls, Bryan

    2006-01-01

    Enterprise streaming has different parameters than consumer Streaming. The government enterprise has some differences on top of that. I'd like to highlight some issues shared by the Federal government as a whole, with a closer look at streaming within NASA. Then we'll look at NASA's strategy for streaming.

  15. THE DYNAMICS OF STAR STREAM GAPS

    SciTech Connect

    Carlberg, R. G.

    2013-10-01

    A massive object crossing a narrow stream of stars orbiting in the halo of the galaxy induces velocity changes both along and transverse to the stream that can lead to the development of a visible gap. For a stream narrow relative to its orbital radius, the stream crossing time is sufficiently short that the impact approximation can be used to derive the changes in angular momenta and radial actions along the star stream. The epicyclic approximation is used to calculate the evolution of the density of the stream as it orbits around in a galactic potential. Analytic expressions are available for a point mass, however, the general expressions are easily numerically evaluated for perturbing objects with arbitrary density profiles. With a simple allowance for the velocity dispersion of the stream, moderately warm streams can be modeled. The predicted evolution agrees well with the outcomes of simulations of stellar streams for streams with widths up to 1% of the orbital radius of the stream. The angular momentum distribution within the stream shears out gaps with time, further reducing the visibility of streams, although the size of the shear effect requires more detailed simulations that account for the creation of the stream. An illustrative model indicates that shear will set a lower limit of a few times the stream width for the length of gaps that persist. In general, the equations are useful for dynamical insights into the development of stream gaps and their measurement.

  16. Hypoxia in the Northern Gulf of Mexico

    SciTech Connect

    Dale, Virginia H

    2010-01-01

    Since 1985, scientists have been documenting a hypoxic zone in the Gulf of Mexico each year. The hypoxic zone, an area of low dissolved oxygen that cannot support marine life, generally manifests itself in the spring. Since marine species either die or flee the hypoxic zone, the spread of hypoxia reduces the available habitat for marine species, which are important for the ecosystem as well as commercial and recreational fishing in the Gulf. Since 2001, the hypoxic zone has averaged 16,500 km{sup 2} during its peak summer months, an area slightly larger than the state of Connecticut, and ranged from a low of 8,500 km{sup 2} to a high of 22,000 km{sup 2}. To address the hypoxia problem, the Mississippi River/Gulf of Mexico Watershed Nutrient Task Force (or Task Force) was formed to bring together representatives from federal agencies, states, and tribes to consider options for responding to hypoxia. The Task Force asked the White House Office of Science and Technology Policy to conduct a scientific assessment of the causes and consequences of Gulf hypoxia through its Committee on Environment and Natural Resources (CENR). In 2000 the CENR completed An Integrated Assessment: Hypoxia in the Northern Gulf of Mexico (or Integrated Assessment), which formed the scientific basis for the Task Force's Action Plan for Reducing, Mitigating, and Controlling Hypoxia in the Northern Gulf of Mexico (Action Plan, 2001). In its Action Plan, the Task Force pledged to implement ten management actions and to assess progress every 5 years. This reassessment would address the nutrient load reductions achieved, the responses of the hypoxic zone and associated water quality and habitat conditions, and economic and social effects. The Task Force began its reassessment in 2005. In 2006 as part of the reassessment, USEPA's Office of Water, on behalf of the Task Force, requested that the U.S. Environmental Protection Agency (USEPA) Science Advisory Board (SAB) convene an independent panel to

  17. The Patriot Experience in the Gulf War -- Implications for Today

    NASA Astrophysics Data System (ADS)

    Lewis, George

    2001-04-01

    As the U.S. moves towards deployment of a National Missile Defense system, it is useful to review our only actual experience with ballistic missile defense the use of the Patriot air defense system against Iraqi Scuds in the 1991 Gulf War. During and immediately after the end of the War, the U.S. Army claimed that Patriot was 96the Scuds. As criticisms of the Army’s assessment were raised, this claim was gradually reduced -- until by April 1992 it was at 61Essentially all of the data used in the Army’s assessment, even the outcome of individual engagements (which were released during the war), are now classified. However, independent analysis of Patriot’s performance using news media videos and other publicly available data shows conclusively that Patriot’s performance was very poor -- that it destroyed very few, and most likely no, Scud warheads. Although this analysis was criticized by Patriot supporters, a review by a panel appointed by the APS Panel on Physics and Public Affairs found no flaws in this analysis and rejected the arguments of its critics. This talk will discuss the publicly available video evidence and show how it can be used to assess the outcome of individual Patriot-Scud engagements. It will then summarize the results of analyzing all of the data, which show that Patriot was ineffective. It will next discuss how the U.S. Army reached its assessed success rate of 61this assessment was based on an incorrect methodology that would give a high success rate even if the actual success rate was zero. Finally, it will discuss why the performance of Patriot in the Gulf War is relevant today and what lessons we can draw from it with regard to current missile defense programs, and the National Missile Defense program in particular.

  18. Surface Topography of the Gulf Stream Region Derived from GEOSAT Altimetry

    DTIC Science & Technology

    1989-10-24

    riIng the collection at information. Send comments regarding thIs burden esftine ofr a-, ( r -- as ,eci (,A D -A 2 68 Ion. to Washington... Prolec I No. ",5 G8 4 6. Author(s). M.R. Carnes and J.L. Mitchell TskNo. 803 Accession No. DN256002 7. Performing Organization Name(s) and Address(es

  19. Biogeochemistry of Submarine Groundwater Discharge to the Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Telfeyan, K.; Breaux, A.; Kim, J.; Kolker, A.; Johannesson, K. H.; Cable, J. E.

    2013-12-01

    Regional radon surveys were initiated in the spring/summer of 2013 to evaluate the potential importance of submarine groundwater discharge (SGD) in the Mississippi River delta region. Buried paleochannels consisting of sand and other relatively coarse grained sediment likely provide transport pathways for substantial fluxes of freshwater and associated dissolved constituents to the Gulf of Mexico through their subsurface linkage with the main river channel and their higher permeability than interdistributary sediments. Initial radon investigations identify potential groundwater inputs to Lac des Allemands preferentially along bayous closest to the Mississippi, especially associated with the peak discharge of the Mississippi. Based on these radon survey results, more focused groundwater and surface water sampling was conducted to characterize the general chemistry of SGD in the region. Generally, pH and Eh change from the fresh groundwater end member to the seawater end member, demonstrating a clear river signal in the SGD and creating a dynamic environment with the potential for multiple geochemical reactions. Major cation data shows a general mixing trend in Lac des Allemands water: samples are more alkaline closest to the Mississippi River end member. Sequential sediment digestions indicate that much of the lake sediments consist of organic matter, which likely lowers the alkalinity of the lake end member. This study will also concentrate on the specific changes in oxyanion chemistry (i.e. arsenic and vanadium) along flowpaths from fresh to saline waters within the local subterranean estuaries. The oxyanions will provide a means to investigate the influence of redox chemistry in subterranean estuaries on the SGD fluxes of trace elements to the local interdistributary bays.

  20. The Midwest Stream Quality Assessment

    USGS Publications Warehouse

    ,

    2012-01-01

    In 2013, the U.S. Geological Survey (USGS) National Water-Quality Assessment Program (NAWQA) and USGS Columbia Environmental Research Center (CERC) will be collaborating with the U.S. Environmental Protection Agency (EPA) National Rivers and Streams Assessment (NRSA) to assess stream quality across the Midwestern United States. The sites selected for this study are a subset of the larger NRSA, implemented by the EPA, States and Tribes to sample flowing waters across the United States (http://water.epa.gov/type/rsl/monitoring/riverssurvey/index.cfm). The goals are to characterize water-quality stressors—contaminants, nutrients, and sediment—and ecological conditions in streams throughout the Midwest and to determine the relative effects of these stressors on aquatic organisms in the streams. Findings will contribute useful information for communities and policymakers by identifying which human and environmental factors are the most critical in controlling stream quality. This collaborative study enhances information provided to the public and policymakers and minimizes costs by leveraging and sharing data gathered under existing programs. In the spring and early summer, NAWQA will sample streams weekly for contaminants, nutrients, and sediment. During the same time period, CERC will test sediment and water samples for toxicity, deploy time-integrating samplers, and measure reproductive effects and biomarkers of contaminant exposure in fish or amphibians. NRSA will sample sites once during the summer to assess ecological and habitat conditions in the streams by collecting data on algal, macroinvertebrate, and fish communities and collecting detailed physical-habitat measurements. Study-team members from all three programs will work in collaboration with USGS Water Science Centers and State agencies on study design, execution of sampling and analysis, and reporting.

  1. Surficial deposits on salt diapirs (Zagros Mountains and Persian Gulf Platform, Iran): Characterization, evolution, erosion and the influence on landscape morphology

    NASA Astrophysics Data System (ADS)

    Bruthans, Jiří; Filippi, Michal; Asadi, Naser; Zare, Mohammad; Šlechta, Stanislav; Churáčková, Zdenka

    2009-06-01

    The surfaces of salt diapirs in the Zagros Mountains are mostly covered by surficial deposits, which significantly affect erosion rates, salt karst evolution, land use and the density of the vegetation cover. Eleven salt diapirs were selected for the study of surficial deposits in order to cover variability in the geology, morphology and climate in a majority of the diapirs in the Zagros Mountains and Persian Gulf Platform. The chemical and mineralogical compositions of 80 selected samples were studied mainly by X-ray powder diffraction and X-ray fluorescence. Changes in salinity along selected vertical profiles were studied together with the halite and gypsum distribution. The subaerial residuum formed from minerals and rock detritus released from the dissolved rock salt is by far the most abundant material on the diapirs. Fluvial sediments derived from this type of residuum are the second most common deposits found, while submarine residuum and marine sediments have only local importance. The mineralogical/chemical composition of surficial deposits varies amongst the three end members: evaporite minerals (gypsum/anhydrite and minor halite), carbonates (dolomite and calcite) and silicates-oxides (mainly quartz, phyllosilicates, and hematite). Based on infiltration tests on different types of surficial deposits, most of the rainwater will infiltrate, while overland flow predominates on rock salt exposures. Recharge concentration and thick accumulations of fine sediment support relatively rich vegetation cover in some places and even enable local agricultural activity. The source material, diapir relief, climatic conditions and vegetation cover were found to be the main factors affecting the development and erosion of surficial deposits. A difference was found in residuum type and landscape morphology between the relatively humid NW part of the studied area and the arid Persian Gulf coast: In the NW, the medium and thick residuum seems to be stable under current

  2. Fuel-cell engine stream conditioning system

    DOEpatents

    DuBose, Ronald Arthur

    2002-01-01

    A stream conditioning system for a fuel cell gas management system or fuel cell engine. The stream conditioning system manages species potential in at least one fuel cell reactant stream. A species transfer device is located in the path of at least one reactant stream of a fuel cell's inlet or outlet, which transfer device conditions that stream to improve the efficiency of the fuel cell. The species transfer device incorporates an exchange media and a sorbent. The fuel cell gas management system can include a cathode loop with the stream conditioning system transferring latent and sensible heat from an exhaust stream to the cathode inlet stream of the fuel cell; an anode humidity retention system for maintaining the total enthalpy of the anode stream exiting the fuel cell related to the total enthalpy of the anode inlet stream; and a cooling water management system having segregated deionized water and cooling water loops interconnected by means of a brazed plate heat exchanger.

  3. Changing climate in the Gulf of California

    NASA Astrophysics Data System (ADS)

    Lluch-Cota, Salvador E.; Parés-Sierra, Alejandro; Magaña-Rueda, Víctor O.; Arreguín-Sánchez, Francisco; Bazzino, Gastón; Herrera-Cervantes, Hugo; Lluch-Belda, Daniel

    2010-10-01

    We conducted a four year interdisciplinary collaborative project focused in the Gulf of California, the most important fishing region for Mexico. We reviewed published reports, collected and analyzed physical, chemical and ecological data sets, and developed models for the physical (atmosphere and ocean) and ecological components of this large marine ecosystem, to examine prevalent scientific questions regarding climate variability and change in the region, covering three time scales (ENSO, decadal-to-interdecadal, and long-term trend). We were able to describe how the Gulf of California influences the northward propagation of coastal trapped Kelvin waves associated with El Niño (ENSO) events, and how this signal, together with changes in the atmospheric forcing, results in a ENSO signature inside the Gulf. For the decadal-to-multidecadal scales, we found coherent trends among series, and with the Pacific Decadal Oscillation (PDO). The long-term temperature signal for the Gulf of California shows a warming that occurred in the mid 20th century, approximately a decade before that in the California Current. This signal is coherent with fluctuations in the industrial fisheries catch records (sardine and shrimps). For the recent decades we found no significant sustained long-term trend in any of the time series of physical and ecological variables that we considered. Instead, variability seems to be fully dominated by the interaction of PDO and ENSO. We stress the urgent need for more modeling efforts and the establishment of interdisciplinary (physical and biological) observation platforms for the marine environment in the Gulf of California.

  4. Acoustic streaming induced by ultrasonic flexural vibrations and associated enhancement of convective heat transfer.

    PubMed

    Loh, Byoung-Gook; Hyun, Sinjae; Ro, Paul I; Kleinstreuer, Clement

    2002-02-01

    Acoustic streaming induced by ultrasonic flexural vibrations and the associated convection enhancement are investigated. Acoustic streaming pattern, streaming velocity, and associated heat transfer characteristics are experimentally observed. Moreover, analytical analysis based on Nyborg's formulation is performed along with computational fluid dynamics (CFD) simulation using a numerical solver CFX 4.3. Two distinctive acoustic streaming patterns in half-wavelength of the flexural vibrations are observed, which agree well with the theory. However, acoustic streaming velocities obtained from CFD simulation, based on the incompressible flow assumption, exceed the theoretically estimated velocity by a factor ranging from 10 to 100, depending upon the location along the beam. Both CFD simulation and analytical analysis reveal that the acoustic streaming velocity is proportional to the square of the vibration amplitude and the wavelength of the vibrating beam that decreases with the excitation frequency. It is observed that the streaming velocity decreases with the excitation frequency. Also, with an open-ended channel, a substantial increase in streaming velocity is observed from CFD simulations. Using acoustic streaming, a temperature drop of 40 degrees C with a vibration amplitude of 25 microm at 28.4 kHz is experimentally achieved.

  5. Streaming Compression of Hexahedral Meshes

    SciTech Connect

    Isenburg, M; Courbet, C

    2010-02-03

    We describe a method for streaming compression of hexahedral meshes. Given an interleaved stream of vertices and hexahedral our coder incrementally compresses the mesh in the presented order. Our coder is extremely memory efficient when the input stream documents when vertices are referenced for the last time (i.e. when it contains topological finalization tags). Our coder then continuously releases and reuses data structures that no longer contribute to compressing the remainder of the stream. This means in practice that our coder has only a small fraction of the whole mesh in memory at any time. We can therefore compress very large meshes - even meshes that do not file in memory. Compared to traditional, non-streaming approaches that load the entire mesh and globally reorder it during compression, our algorithm trades a less compact compressed representation for significant gains in speed, memory, and I/O efficiency. For example, on the 456k hexahedra 'blade' mesh, our coder is twice as fast and uses 88 times less memory (only 3.1 MB) with the compressed file increasing about 3% in size. We also present the first scheme for predictive compression of properties associated with hexahedral cells.

  6. Rationale, Design, Methodology and Hospital Characteristics of the First Gulf Acute Heart Failure Registry (Gulf CARE)

    PubMed Central

    Sulaiman, Kadhim J.; Panduranga, Prashanth; Al-Zakwani, Ibrahim; Alsheikh-Ali, Alawi; Al-Habib, Khalid; Al-Suwaidi, Jassim; Al-Mahmeed, Wael; Al-Faleh, Husam; El-Asfar, Abdelfatah; Al-Motarreb, Ahmed; Ridha, Mustafa; Bulbanat, Bassam; Al-Jarallah, Mohammed; Bazargani, Nooshin; Asaad, Nidal; Amin, Haitham

    2014-01-01

    Background: There is paucity of data on heart failure (HF) in the Gulf Middle East. The present paper describes the rationale, design, methodology and hospital characteristics of the first Gulf acute heart failure registry (Gulf CARE). Materials and Methods: Gulf CARE is a prospective, multicenter, multinational registry of patients >18 year of age admitted with diagnosis of acute HF (AHF). The data collected included demographics, clinical characteristics, etiology, precipitating factors, management and outcomes of patients admitted with AHF. In addition, data about hospital readmission rates, procedures and mortality at 3 months and 1-year follow-up were recorded. Hospital characteristics and care provider details were collected. Data were entered in a dedicated website using an electronic case record form. Results: A total of 5005 consecutive patients were enrolled from February 14, 2012 to November 13, 2012. Forty-seven hospitals in 7 Gulf States (Oman, Saudi Arabia, Yemen, Kuwait, United Gulf Emirates, Qatar and Bahrain) participated in the project. The majority of hospitals were community hospitals (46%; 22/47) followed by non-University teaching (32%; 15/47 and University hospitals (17%). Most of the hospitals had intensive or coronary care unit facilities (93%; 44/47) with 59% (28/47) having catheterization laboratory facilities. However, only 29% (14/47) had a dedicated HF clinic facility. Most patients (71%) were cared for by a cardiologist. Conclusions: Gulf CARE is the first prospective registry of AHF in the Middle East, intending to provide a unique insight into the demographics, etiology, management and outcomes of AHF in the Middle East. HF management in the Middle East is predominantly provided by cardiologists. The data obtained from this registry will help the local clinicians to identify the deficiencies in HF management as well as provide a platform to implement evidence based preventive and treatment strategies to reduce the burden of HF in

  7. Summary of Training Workshop on the Use of NASA tools for Coastal Resource Management in the Gulf of Mexico

    SciTech Connect

    Judd, Chaeli; Judd, Kathleen S.; Gulbransen, Thomas C.; Thom, Ronald M.

    2009-03-01

    A two-day training workshop was held in Xalapa, Mexico from March 10-11 2009 with the goal of training end users from the southern Gulf of Mexico states of Campeche and Veracruz in the use of tools to support coastal resource management decision-making. The workshop was held at the computer laboratory of the Institute de Ecologia, A.C. (INECOL). This report summarizes the results of that workshop and is a deliverable to our NASA client.

  8. A model for evaluating stream temperature response to climate change in Wisconsin

    USGS Publications Warehouse

    Stewart, Jana S.; Westenbroek, Stephen M.; Mitro, Matthew G.; Lyons, John D.; Kammel, Leah E.; Buchwald, Cheryl A.

    2015-01-01

    Integrating the SWB Model with the ANN Model provided a mechanism by which downscaled global or regional climate model results could be used to estimate the potential effects of climate change on future stream temperature on a daily time step. To address future climate scenarios, statistically downscaled air temperature and precipitation projections from 10 GCMs and 2 time periods were used with the SWB-ANNv1 Model to project future stream temperature. Projections of future stream temperatures at mid- (2046–65) and late- (2081–2100) 21st century showed the July mean water temperature increasing for all stream segments with about 80 percent of stream kilometers increasing by 1 to 2 degrees Celsius (°C) by mid-century and about 99 percent increasing by 1 to 3 °C by late-century. Projected changes in stream temperatures also affected changes in thermal classes with a loss in the total amount of cold-water, cold-transition, and warm-transition thermal habitat and a gain in warm-water and very warm thermal habitat for both mid- and late-21st century time periods. The greatest losses occurred for cold-water streams and the greatest gains for warm-water streams, with a contraction of cold-water streams in the Driftless Area of western and southern Wisconsin and an expansion of warm-water streams across northern Wisconsin. Results of this study suggest that such changes will affect the composition of fish assemblages, with a loss of suitable habitat for cold-water fishes and gain in suitable habitat for warm-water fishes. In the end, these projected changes in thermal habitat attributable to climate may result in a net loss of fisheries, because many warm-water species may be unable to colonize habitats formerly occupied by cold-water species because of other habitat limitations (e.g., stream size, gradient). Although projected stream temperatures may vary greatly, depending on the emissions scenario and models used, the results presented in this report represent one

  9. Meteoroid streams and comet disintegration

    NASA Astrophysics Data System (ADS)

    Guliyev, A.

    2016-01-01

    The results of the statistical analysis of the dynamic parameters of 114 comets that have undergone nuclear splitting are presented in the article. The list of the objects contains: comets that have split in the period of the observation; data of twin-comets; lost comets with designation D; comets with large-scale structure in the coma. We will describe these comets as "splitted". Some aspects of the following hypothesis are studied: disintegration of comet nuclei happens as the result of their collision with meteoroid streams. For the verification of this hypothesis, the position of splitted comet orbits relatively to 125 meteor streams from Kronk's list is analyzed. It was found that the total number of comet orbit nodes located close to the meteor stream planes (for the distances up to 0.1 AU) is N = 1041. It is shown that if these comets are replaced by randomly selected different comets, N will be reduced by a factor of approximately three.

  10. Dynamic visualization of data streams

    DOEpatents

    Wong, Pak Chung; Foote, Harlan P.; Adams, Daniel R.; Cowley, Wendy E.; Thomas, James J.

    2009-07-07

    One embodiment of the present invention includes a data communication subsystem to receive a data stream, and a data processing subsystem responsive to the data communication subsystem to generate a visualization output based on a group of data vectors corresponding to a first portion of the data stream. The processing subsystem is further responsive to a change in rate of receipt of the data to modify the visualization output with one or more other data vectors corresponding to a second portion of the data stream as a function of eigenspace defined with the group of data vectors. The system further includes a display device responsive to the visualization output to provide a corresponding visualization.

  11. A Robust Streaming Media System

    NASA Astrophysics Data System (ADS)

    Youwei, Zhang

    Presently, application layer multicast protocols (ALM) are proposed as substitute for IP multicast and have made extraordinary achievements. Integrated with Multi-data-stream mode such as Multiple Description Coding (MDC), ALM becomes more scalable and robust in high-dynamic Internet environment compared with single data stream. Although MDC can provide a flexible data transmission style, the synchronization of different descriptions encoded from one video source is proved to be difficult due to different delay on diverse transmission paths. In this paper, an ALM system called HMDC is proposed to improve accepted video quality of streaming media, hosts can join the separate overlay trees in different layers simultaneously, then the maximum synchronized descriptions of the same layer are worked out to acquire the best video quality. Simulations implemented on Internet-like topology indicate that HMDC achieves better video quality, lower link stress, higher robustness and comparable latency compared with traditional ALM protocols.

  12. Start at the End ...

    ERIC Educational Resources Information Center

    Goldsworthy, Anne

    2005-01-01

    Start at the end; that's the way to improve children's plans for investigations. Strange as it may seem, there are times when beginning at the beginning of an investigation is not the best way to start things off. To give children the opportunity to ask questions and plan what to do, sometimes it is best to get them first to consider others' data…

  13. The North End Boston.

    ERIC Educational Resources Information Center

    Connally, Nicole; And Others

    Goals and objectives, student activities, and evaluations are contained in this guide for a one-day scavenger hunt through the North End of Boston. The culmination of a unit involving urban planning and land-use problems, the field trip is intended to give students first-hand experience with city life and a better understanding of urban issues…

  14. End-Stage.

    ERIC Educational Resources Information Center

    Moua, Mai Neng

    2001-01-01

    Through her reflections on dealing with dialysis for end-stage renal disease and awaiting a kidney transplant, the author presents insights into how her experience was shaped by the physical, emotional, and multicultural forces she faced. Among the issues discussed are her ambivalent feelings between pursuing a regular lifestyle and receiving…

  15. Holocene development of the eastern Gulf of Finland coastal zone (Baltic Sea)

    NASA Astrophysics Data System (ADS)

    Ryabchuk, Daria; Sergeev, Alexander; Gusentsova, Tatiana; Gerasimov, Dmitry; Zhamoida, Vladimir; Amantov, Aleksey; Kulkova, Marianna; Sorokin, Peter

    2014-05-01

    In 2011-2013 geoarcheological and marine geological research of the eastern Gulf of Finland coasts and near-shore bottom were undertaken. Researches were concentrated within several key-areas (Sestroretskaya Lowland, Narva-Luga Klint Bay and southern coastal zone of the Gulf (near Bolshaya Izhora village). Study areas can provide important information about Gulf of Finland Holocene coastal development as since Ancylus time (about 10000 cal.BP). Development of numerous sand accretion forms (spits, bars, dunes) of different shape, age and genesis caused formation of lagoon systems, situated now on-land due to land uplift. Coasts of lagoons in Sestroretskaya Lowland and Narva-Luga Klint Bay were inhabited by Neolithic and Early Metal people. Analysis of coastal morphology and results of geological research (GIS relief analyses, ground penetrating radar, drilling, grain-size analyses, radiocarbon dating) and geoarcheological studies allowed to reconstruct the mechanism of large accretion bodies (bars and spits) and lagoon systems formation during last 8000 years. Geoarcheological studies carried out within eastern Gulf of Finland coasts permitted to find some features of the Neolithic - Early Metal settlements distribution. Another important features of the eastern Gulf of Finland coastal zone relief are the series of submarine terraces found in the Gulf bottom (sea water depths 10 to 2 m). Analyses of the submarine terraces morphology and geology (e.g. grain-size distribution, pollen analyses and organic matter dating) allow to suppose that several times during Holocene (including preAncylus (11000 cal.BP) and preLittorina (8500 cal.BP) regressions) the sea-water level was lower than nowadays. During the maximal stage of the Littorina transgression (7600-7200 cal. BP) several open bays connected with the Littorina Sea appeared in this area. The lagoon systems and sand accretion bodies (spits and bars) were formed during the following decreasing of the sea level. Late

  16. Evaluation of ecotourism potential in the northern coastline of the Persian Gulf

    NASA Astrophysics Data System (ADS)

    Nouri, Jafar; Danehkar, Afshin; Sharifipour, Rozita

    2008-08-01

    This research has identified areas located in the northern coastline of the Persian Gulf in the south of Iran, as strategic and ecological sites, based on tourism potential assessing criteria. To this end coastal limits were identified by satellite imagery in terms of shorelines and the maximum extent of water approach into the land and taking into consideration the characteristics of the nearby coastal villages. The studied region was then compared to similar international criteria and experiences. The original criteria were then divided into three main and four sub criteria. The Kangan region was found to have a potential for tourism industry according to the mentioned criteria. Naiband Gulf with a score of 20 was ranked first followed by Asalouyeh with a score of 18 and finally Taheri and Kangan Ports with scores of 16 and 15, respectively. With a high tourism industry potential in the studied region the necessity of ecotourism quality enhancement and environmental management planning for the northern shoreline of the Persian Gulf becomes of vital importance.

  17. Streaming Potential In Rocks Saturated With Water And Oil

    NASA Astrophysics Data System (ADS)

    Tarvin, J. A.; Caston, A.

    2011-12-01

    Fluids flowing through porous media generate electrical currents. These currents cause electric potentials, called "streaming potentials." Streaming potential amplitude depends on the applied pressure gradient, on rock and fluid properties, and on the interaction between rock and fluid. Streaming potential has been measured for rocks saturated with water (1) and with water-gas mixtures. (2) Few measurements (3) have been reported for rocks saturated with water-oil mixtures. We measured streaming potential for sandstone and limestone saturated with a mixture of brine and laboratory oil. Cylindrical samples were initially saturated with brine and submerged in oil. Saturation was changed by pumping oil from one end of a sample to the other and then through the sample in the opposite direction. Saturation was estimated from sample resistivity. The final saturation of each sample was determined by heating the sample in a closed container and measuring the pressure. Measurements were made by modulating the pressure difference (of oil) between the ends of a sample at multiple frequencies below 20 Hz. The observed streaming potential is a weak function of the saturation. Since sample conductivity decreases with increasing oil saturation, the electro-kinetic coupling coefficient (Pride's L (4)) decreases with increasing oil saturation. (1) David B. Pengra and Po-zen Wong, Colloids and Surfaces, vol., p. 159 283-292 (1999). (2) Eve S. Sprunt, Tony B. Mercer, and Nizar F. Djabbarah, Geophysics, vol. 59, p. 707-711 (1994). (3) Vinogradov, J., Jackson, M.D., Geophysical Res. L., Vol. 38, Article L01301 (2011). (4) Steve Pride, Phys. Rev. B, vol. 50, pp. 15678-15696 (1994).

  18. Morphodynamics of supraglacial streams (Invited)

    NASA Astrophysics Data System (ADS)

    Karlstrom, L.; Manga, M.; Gajjar, P.

    2010-12-01

    Supraglacial hydrologic networks exhibit structure and morphodynamics reminiscent of alluvial channels, in an environment where the primary mechanism of erosion is thermal and timescales of topographic adjustment are days to weeks. Supraglacial stream incision is strongly modulated by solar forcing, at times faster or slower than the large-scale lowering of the glacial surface. This variability, in combination with control by structures within the ice or other surface topography, produces a time-evolving drainage network over the course of the melt season. Near the snow line, porous ice facilitates channel development and abandonment via seepage, whereas near the terminus channels are more stable and larger in scale. Discharge generally increases with drainage area, except in cases where water is lost through moulins or crevasses. We report here on fieldwork at the Mendenhall and Llewellyn glaciers on the Juneau Icefield, aimed at better characterizing flow and incision dynamics of supraglacial streams. Time series of temperature, velocity and isotopic composition reveal diurnal variability in flow processes, with clear discharge dependence. GPS profiles show slope dependence of stream sinuousity, and we observe differential incision of ice surface and streams along with downstream migration of meanders and of ice bedforms. We document drainage density, and identify subsurface water movement near the snow line that facilitates channelization. These field measurements are used to develop and validate a theoretical model of meander formation in supraglacial streams, based on the framework of bend theory in alluvial meanders (Karlstrom et al., in review). We find empirically that meandering in supraglacial streams globally follows the linear wavelength-width power law relation found in alluvial and bedrock rivers, but with a smaller intercept. Our linear theory can reproduce this relation, as well as the observed downstream migration of meanders.

  19. United States military strategy in the Persian Gulf. Study project

    SciTech Connect

    Whitehead, E.E.

    1989-03-27

    The importance of Persian Gulf oil, in the context of United States national security has been demonstrated in recent political, economic, and military terms. Substantial United States military resources have been devoted to maintain national security interests in the Persian Gulf region. This paper analyzes the United States military strategy designed to insure the US and its allies continued access to Persian Gulf oil and to suggest alternatives for possible improvement. Although the focus is on US military strategy in the Persian Gulf, it also covers others aspects of US national security policy and strategy. US military policy in the Persian Gulf is derived from a complex process that inextricably links the elements of national strategy with the elements of national power. Conclusions about US policy and strategy in the Persian Gulf that are properly focused and logical require an understanding of US interests and their priorities; US strategies and their feasibility; plus US capabilities and their limitations.

  20. The structures, stratigraphy and evolution of the Gulf of Corinth rift, Greece

    NASA Astrophysics Data System (ADS)

    Taylor, Brian; Weiss, Jonathan R.; Goodliffe, Andrew M.; Sachpazi, Maria; Laigle, Mireille; Hirn, Alfred

    2011-06-01

    A multichannel seismic and bathymetry survey of the central and eastern Gulf of Corinth (GoC), Greece, reveals the offshore fault geometry, seismic stratigraphy and basin evolution of one of Earths most active continental rift systems. Active, right-stepping, en-echelon, north-dipping border faults trend ESE along the southern Gulf margin, significantly overlapping along strike. The basement offsets of three (Akrata-Derveni, Sithas and Xylocastro) are linked. The faults are biplanar to listric: typically intermediate angle (˜35° in the centre and 45-48° in the east) near the surface but decreasing in dip and/or intersecting a low- or shallow-angle (15-20° in the centre and 19-30° in the east) curvi-planar reflector in the basement. Major S-dipping border faults were active along the northern margin of the central Gulf early in the rift history, and remain active in the western Gulf and in the subsidiary Gulf of Lechaio, but unlike the southern border faults, are without major footwall uplift. Much of the eastern rift has a classic half-graben architecture whereas the central rift has a more symmetric w- or u-shape. The narrower and shallower western Gulf that transects the >40-km-thick crust of the Hellenides is associated with a wider distribution of overlapping high-angle normal faults that were formerly active on the Peloponnesus Peninsula. The easternmost sector includes the subsidiary Gulfs of Lechaio and Alkyonides, with major faults and basement structures trending NE, E-W and NW. The basement faults that control the rift architecture formed early in the rift history, with little evidence (other than the Vrachonisida fault along the northern margin) in the marine data for plan view evolution by subsequent fault linkage. Several have maximum offsets near one end. Crestal collapse graben formed where the hanging wall has pulled off the steeper onto the shallower downdip segment of the Derveni Fault. The dominant strikes of the Corinth rift faults

  1. NASA'S SERVIR Gulf of Mexico Project: The Gulf of Mexico Regional Collaborative (GoMRC)

    NASA Technical Reports Server (NTRS)

    Quattrochi, Dale A.; Irwin, Daniel; Presson, Joan; Estes, Maury; Estes, Sue; Judd, Kathleen

    2006-01-01

    The Gulf of Mexico Regional Collaborative (GoMRC) is a NASA-funded project that has as its goal to develop an integrated, working, prototype IT infrastructure for Earth science data, knowledge and models for the five Gulf U.S. states and Mexico, and to demonstrate its ability to help decision-makers better understand critical Gulf-scale issues. Within this preview, the mission of this project is to provide cross cutting solution network and rapid prototyping capability for the Gulf of Mexico region, in order to demonstrate substantial, collaborative, multi-agency research and transitional capabilities using unique NASA data sets and models to address regional problems. SERVIR Mesoamerica is seen as an excellent existing framework that can be used to integrate observational and GIs data bases, provide a sensor web interface, visualization and interactive analysis tools, archival functions, data dissemination and product generation within a Rapid Prototyping concept to assist decision-makers in better understanding Gulf-scale environmental issues.

  2. Salamander occupancy in headwater stream networks

    USGS Publications Warehouse

    Grant, E.H.C.; Green, L.E.; Lowe, W.H.

    2009-01-01

    1. Stream ecosystems exhibit a highly consistent dendritic geometry in which linear habitat units intersect to create a hierarchical network of connected branches. 2. Ecological and life history traits of species living in streams, such as the potential for overland movement, may interact with this architecture to shape patterns of occupancy and response to disturbance. Specifically, large-scale habitat alteration that fragments stream networks and reduces connectivity may reduce the probability a stream is occupied by sensitive species, such as stream salamanders. 3. We collected habitat occupancy data on four species of stream salamanders in first-order (i.e. headwater) streams in undeveloped and urbanised regions of the eastern U.S.A. We then used an information-theoretic approach to test alternative models of salamander occupancy based on a priori predictions of the effects of network configuration, region and salamander life history. 4. Across all four species, we found that streams connected to other first-order streams had higher occupancy than those flowing directly into larger streams and rivers. For three of the four species, occupancy was lower in the urbanised region than in the undeveloped region. 5. These results demonstrate that the spatial configuration of stream networks within protected areas affects the occurrences of stream salamander species. We strongly encourage preservation of network connections between first-order streams in conservation planning and management decisions that may affect stream species.

  3. Push-Pull Two-Layer Super-Peer based P2P Live Media Streaming

    NASA Astrophysics Data System (ADS)

    Hoong, Poo Kuan; Matsuo, Hiroshi

    Peer-to-peer (P2P) file sharing has become increasingly popular, accounting for as much as 70% of Internet traffic by some estimates. Recently, we have been witnessing the emergence of a new class of popular P2P applications, namely, P2P audio and video streaming. In this study, we propose and investigate a full distributed, scalable and cooperative protocol for live video streaming in an overlay peer-to-peer network. Our protocol, termed P2P Super-Peer based Unstructured Live Media Streaming (PALMS-SP), makes use of combination of push-pull scheduling methods to achieve high performance (in term of delay, stream continuity, cooperation, etc.). The main contribution of PALMS-SP is that it reduces the end-to-end streaming delay and in turn results better delivered quality. We have extensively evaluated the performance of PALMS-SP. Our experiments demonstrate that PALMS-SP with the existence of super-peers achieves better streaming quality in comparison with other existing streaming applications.

  4. Trial of Naltrexone and Dextromethorphan for Gulf War Veterans Illnesses

    DTIC Science & Technology

    2011-07-01

    W81XWH-09-2-0065 TITLE: Trial of Naltrexone and Dextromethorphan for Gulf War Veterans Illnesses PRINCIPAL INVESTIGATOR: William J. Meggs, MD...2011 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Trial of Naltrexone and Dextromethorphan for Gulf War Veterans’ Illness 5b. GRANT NUMBER W81XWH-09...that many with Gulf War Illness could enter either the naltrexone or dextromethorphan arm but not both. We are applying to allow subjects to enter

  5. Seagrasses in northern Gulf of Mexico: An ecosystem in trouble

    USGS Publications Warehouse

    ,

    2000-01-01

    The USGS National Wetlands Research Center has documented that Seagrasses in the northern Gulf of Mexico constitute an ecosystem in trouble. From studies in St. Andrews Bay, Period Bay, the Chandeleur Islands, and the Gulf Islands National Seashore, scientists have discovered that declining seagrass acreage ranges from 12% to 66% in bays and estuaries of the Gulf of Mexico. Not only are seagrasses disappearing, but they are also changing in species composition, densities, and patchiness.

  6. Live HDR video streaming on commodity hardware

    NASA Astrophysics Data System (ADS)

    McNamee, Joshua; Hatchett, Jonathan; Debattista, Kurt; Chalmers, Alan

    2015-09-01

    High Dynamic Range (HDR) video provides a step change in viewing experience, for example the ability to clearly see the soccer ball when it is kicked from the shadow of the stadium into sunshine. To achieve the full potential of HDR video, so-called true HDR, it is crucial that all the dynamic range that was captured is delivered to the display device and tone mapping is confined only to the display. Furthermore, to ensure widespread uptake of HDR imaging, it should be low cost and available on commodity hardware. This paper describes an end-to-end HDR pipeline for capturing, encoding and streaming high-definition HDR video in real-time using off-the-shelf components. All the lighting that is captured by HDR-enabled consumer cameras is delivered via the pipeline to any display, including HDR displays and even mobile devices with minimum latency. The system thus provides an integrated HDR video pipeline that includes everything from capture to post-production, archival and storage, compression, transmission, and display.

  7. 2. Historic American Buildings Survey INTERIOR, PULPIT END (SOUTHEAST END) ...

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

    2. Historic American Buildings Survey INTERIOR, PULPIT END (SOUTHEAST END) Lanny Miyamoto, Photographer - October 1958 - Eutaw Place Baptist Church, Dolphin & Eutaw Streets, Baltimore, Independent City, MD

  8. 77 FR 39998 - Gulf of Mexico Fishery Management Council; Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-06

    ...The Gulf of Mexico Fishery Management Council (Council) will convene its Law Enforcement Advisory Panel (LEAP) in conjunction with the Gulf States Marine Fisheries Commission's Law Enforcement Committee...

  9. Gravity-dependent polarity of cytoplasmic streaming in Nitellopsis

    NASA Technical Reports Server (NTRS)

    Wayne, R.; Staves, M. P.; Leopold, A. C.

    1990-01-01

    The internodal cells of the characean alga Nitellopsis obtusa were chosen to investigate the effect of gravity on cytoplasmic streaming. Horizontal cells exhibit streaming with equal velocities in both directions, whereas in vertically oriented cells, the downward-streaming cytoplasm flows ca. 10% faster than the upward-streaming cytoplasm. These results are independent of the orientation of the morphological top and bottom of the cell. We define the ratio of the velocity of the downward- to the upward-streaming cytoplasm as the polar ratio (PR). The normal polarity of a cell can be reversed (PR < 1) by treatment with neutral red (NR). The NR effect may be the result of membrane hyperpolarization, caused by the opening of K+ channels. The K+ channel blocker TEA Cl- inhibits the NR effect. External Ca2+ is required for normal graviresponsiveness. The [Ca2+] of the medium determines the polarity of cytoplasmic streaming. Less than 1 micromole Ca2+ resulted in a PR < 1 while greater than 1 micromole Ca2+ resulted in the normal gravity response. The voltage-dependent Ca(2+)-channel blocker, nifedipine, inhibited the gravity response in a reversible manner, while treatment with LaCl3 resulted in a PR < 1, indicating the presence of two types of Ca2+ channels. A new model for graviperception is presented in which the whole cell acts as the gravity sensor, and the plasma membrane acts as the gravireceptor. This is supported by ligation and UV irradiation experiments which indicate that the membranes at both ends of the cell are required for graviperception. The density of the external medium also affects the PR of Nitellopsis. Calculations are presented that indicate that the weight of the protoplasm may provide enough potential energy to open ion channels.

  10. Response of imperiled Okaloosa darters to stream restoration

    USGS Publications Warehouse

    Reeves, David B.; Tate, William B.; Jelks, Howard; Jordan, Frank

    2016-01-01

    The Okaloosa Darter Etheostoma okaloosae is a small percid endemic to six stream drainages in northwestern Florida. The U.S. Fish and Wildlife Service listed Okaloosa Darters as endangered in 1973 and downlisted them to threatened in 2011 because of habitat improvements and increasing abundance across much of their geographic range. Delisting is possible if remaining recovery criteria are met, including restoration of degraded stream reaches. Impounded reaches of Anderson Branch, Mill Creek, and Toms Creek were restored by removing impediments to water flow, draining impoundments, and reconstructing stream reaches. Restorations of Anderson Branch and Mill Creek were designed to rehabilitate populations of Okaloosa Darters without significantly affecting popular recreational activities at these locations. Restorations were evaluated from 2007 to 2013 by comparing counts of Okaloosa Darters and the composition of microhabitats in restored and nearby undisturbed reference sites. Okaloosa Darters were absent from degraded stream reaches at the beginning of the study, but they rapidly colonized once restorations were completed. Counts of Okaloosa Darters in reference and restoration sites in Anderson Branch were similar by the end of the study, whereas counts in restoration sites were significantly lower than nearby reference sites in Mill and Toms creeks. Restoration sites tended to have lower coverage of sand and root and higher coverage of macrophytes. As riparian vegetation surrounding restoration sites matures to a closed canopy that reduces excessive growth of macrophytes, stream microhabitats and numbers of darters will probably become similar to reference sites. Restoration of degraded stream sites increased abundance and distribution of Okaloosa Darters and reconnected formerly isolated upstream and downstream populations. These projects demonstrated that restoration is a useful conservation tool for imperiled fishes such as Okaloosa Darters and can be

  11. Riparian influences on stream fish assemblage structure in urbanizing streams

    USGS Publications Warehouse

    Roy, A.H.; Freeman, B.J.; Freeman, Mary C.

    2007-01-01

    We assessed the influence of land cover at multiple spatial extents on fish assemblage integrity, and the degree to which riparian forests can mitigate the negative effects of catchment urbanization on stream fish assemblages. Riparian cover (urban, forest, and agriculture) was determined within 30 m buffers at longitudinal distances of 200 m, 1 km, and the entire network upstream of 59 non-nested fish sampling locations. Catchment and riparian land cover within the upstream network were highly correlated, so we were unable to distinguish between those variables. Most fish assemblage variables were related to % forest and % urban land cover, with the strongest relations at the largest spatial extent of land cover (catchment), followed by riparian land cover in the 1-km and 200-m reach, respectively. For fish variables related to urban land cover in the catchment, we asked whether the influence of riparian land cover on fish assemblages was dependent on the amount of urban development in the catchment. Several fish assemblage metrics (endemic richness, endemic:cosmopolitan abundance, insectivorous cyprinid richness and abundance, and fluvial specialist richness) were all best predicted by single variable models with % urban land cover. However, endemic:cosmopolitan richness, cosmopolitan abundance, and lentic tolerant abundance were related to % forest cover in the 1-km stream reach, but only in streams that had <15% catchment urban land cover. In these cases, catchment urbanization overwhelmed the potential mitigating effects of riparian forests on stream fishes. Together, these results suggest that catchment land cover is an important driver of fish assemblages in urbanizing catchments, and riparian forests are important but not sufficient for protecting stream ecosystems from the impacts of high levels of urbanization.

  12. Seismic reflection characteristics of glacial and glacimarine sediment in the Gulf of Alaska and adjacent fjords

    USGS Publications Warehouse

    Carlson, P.R.

    1989-01-01

    Glaciation together with tectonism have been dominant factors affecting sedimentation in the Gulf of Alaska area from at least the late Miocene throughout the Quaternary. The effects of tectonism are apparent in high mountains that border the gulf, raised terraces of Middleton Island and the eastern gulf coastal zone, and numerous active faults and related earthquakes. Glacial evidence includes magnificent glaciers and their onshore deposits, spectacular fjords, large sea valleys incised in the continental shelf, submarine morainal ridges at mouths of bays and sea valleys, and thick glacimarine sedimentary sequences (diamicts) that are exposed onshore and at the sea floor along the outer shelf. Seismic-reflection profiling and sampling of the uppermost marine sedimentary sequences in the Gulf of Alaska and adjacent fjords and bays have allowed identification of three discrete glacially related stratigraphic units. These units were delineated on the basis of seismic signature, geometry, physiographic location, stratigraphic position, and sedimentologic characteristics. The oldest unit, a Quaternary diamict, is portrayed on seismic profiles by irregular, discontinuous reflections. This unit probably includes till, outwash and glacimarine sediment. A geographically restricted unit, one incorporating Holocene end moraines at bay mouths and associated with some sea valleys, consists of jumbled masses of discontinuous reflections and very irregular surface morphology. The youngest unit, a blanket of Holocene sand to clayey silt prograding as a sediment wedge across the shelf, contains nearly horizontal, parallel reflections except where disrupted by mass movement. Although seismic-reflection data alone cannot provide definitive proof of the presence of glacial sediment, when combined with sea-floor sampling, seismic profiling is a powerful tool for determining the continuity of marine sedimentary units and relationships to past and modern glaciers. ?? 1989.

  13. The January 2010 Efpalion earthquakes (Gulf of Corinth, Central Greece): earthquake interactions and blind normal faulting

    NASA Astrophysics Data System (ADS)

    Ganas, Athanassios; Chousianitis, Kostas; Batsi, Evaggelia; Kolligri, Maria; Agalos, Apostolos; Chouliaras, Gerassimos; Makropoulos, Kostas

    2013-04-01

    On 18 January 2010, 15:56 UTC, a M w = 5.1 (National Observatory of Athens; NOA) earthquake occurred near the town of Efpalion (western Gulf of Corinth, Greece), about 10 km to the east of Nafpaktos, along the north coast of the Gulf. Another strong event occurred on 22 January 2010, 00:46 UTC with M w = 5.1 (NOA) approximately 3 km to the NE of the first event. We processed the seismological and geodetic data to examine fault plane geometry, dip direction, and earthquake interactions at the western tip of the Corinth rift. Our data include relocated epicenters of 1,760 events for the period January-June 2010 and daily global positioning system observations from the Efpalio station for the period 1 December 2009-1 March 2010. We suggest that the first event ruptured a blind, north-dipping fault, accommodating north-south extension of the Western Gulf of Corinth. The dip direction of the second event is rather unclear, although a south dip plane is weakly imaged in the post-22 January 2010 aftershock distribution. A Coulomb stress model based on homogeneous slip distribution of the first event showed static stress triggering of the second event of the order of 22-34 KPa that was transferred along the plane of failure. We also point out the existence of north dipping, high-angle faults at 10-15 km depths, which were reactivated because of Coulomb stress transfer, to the west and south of Efpalion. The January 2010 earthquakes ended a 15-year-old quiescence in that area of the Gulf. The crustal volume near Efpalion was also characterized by b values in the range 0.6-0.8 (1970-2010 period).

  14. Habitat Suitability Index Models: Southern and gulf flounders

    USGS Publications Warehouse

    Enge, Kevin M.; Mulholland, Rosemarie

    1985-01-01

    Both the southern and gulf flounders (paralichthrS lethostigma, f. albi~utta) are important commercial and recreationa species. Catch statlstics for flounder do not differentiate between species; however, southern flounders are more common than gulf flounders except on the gulf coast of Florida (Topp and Hoff 1972). The commercial fishery consists of incidental catches by shrimp trawlers. A total of 853,162 kg (1,880,900 lb) of unclassified flounder worth $572,142 was caught from the Gulf of Mexico in 1976 (U.S. Dep. Commerce 1980). The sport fishery consists of both hook-and-line fishing and gigging.

  15. Plate tectonics and the Gulf of California region

    SciTech Connect

    Schmidt, N.

    1990-11-01

    The geology and tectonism of California have been influenced greatly by the collision and interaction between the Pacific plate and the North American plate. The forces generated by this interaction caused substantial horizontal movement along the San Andreas fault system and created the Gulf of California rift zone. This article summarizes the unique features of the gulf, describes the theory of plate tectonics, explains how tectonism may have affected the geologic evolution and physiography of the gulf, and illustrates the process by which the Colorado River became linked to the gulf.

  16. Mercury in the Gulf of Mexico: sources to receptors.

    PubMed

    Harris, Reed; Pollman, Curtis; Landing, William; Evans, David; Axelrad, Donald; Hutchinson, David; Morey, Steven L; Rumbold, Darren; Dukhovskoy, Dmitry; Adams, Douglas H; Vijayaraghavan, Krish; Holmes, Christopher; Atkinson, R Dwight; Myers, Tom; Sunderland, Elsie

    2012-11-01

    Gulf of Mexico (Gulf) fisheries account for 41% of the U.S. marine recreational fish catch and 16% of the nation's marine commercial fish landings. Mercury (Hg) concentrations are elevated in some fish species in the Gulf, including king mackerel, sharks, and tilefish. All five Gulf states have fish consumption advisories based on Hg. Per-capita fish consumption in the Gulf region is elevated compared to the U.S. national average, and recreational fishers in the region have a potential for greater MeHg exposure due to higher levels of fish consumption. Atmospheric wet Hg deposition is estimated to be higher in the Gulf region compared to most other areas in the U.S., but the largest source of Hg to the Gulf as a whole is the Atlantic Ocean (>90%) via large flows associated with the Loop Current. Redistribution of atmospheric, Atlantic and terrestrial Hg inputs to the Gulf occurs via large scale water circulation patterns, and further work is needed to refine estimates of the relative importance of these Hg sources in terms of contributing to fish Hg levels in different regions of the Gulf. Measurements are needed to better quantify external loads, in-situ concentrations, and fluxes of total Hg and methylmercury in the water column, sediments, and food web.

  17. Western economies and the Gulf war

    SciTech Connect

    Rowen, H.S.

    1980-12-01

    A prolonged Iran/Iraq war could mean economic and even political-military disaster for western countries dependent on Persian Gulf oil. The percentage of gross national product loss that the US, western Europe, and Japan would suffer is estimated for three levels of interruption and illustrates how global effects can be felt even when direct imports are not involved. Although the US has few options for projecting power into the Gulf region, a long-run expansion of military capability is essential. The economic damage of continued disruptions can be eased by using more coal, nuclear power, and natural gas even if it means removing some environmental and economic barriers. A combination of financial incentives and additions to the strategic oil and gas storage would help, but important change will come from a reappraisal of our military position. (DCK)

  18. Survey to assess Persian Gulf spill effects

    SciTech Connect

    Not Available

    1992-02-10

    This paper reports that an international group is poised for an extensive survey of the Persian Gulf, including an assessment of the long term effects of last year's oil spill, a legacy of the Persian Gulf war. Saudi Arabia plans a $450 million cleanup program on beaches fouled by the massive spill. Plans for the survey were disclosed by the United National Educational, Scientific and Cultural Organization (Unesco). It is to be carried out under the auspices of the Regional Organization for the Protection of the Marine Environment (Ropme), Unesco's Intergovernmental Oceanographic Commission, and the U.S. National Oceanic and Atmospheric Administration. Ropme member countries are Bahrain, Iran, Iraq, Kuwait, Qatar, Saudi Arabia, and the United Arab Emirates.

  19. Robotic end effector

    DOEpatents

    Minichan, R.L.

    1993-10-05

    An end effector is described for use in probing a surface with a robotic arm. The end effector has a first portion that carries a gimbal with a probe, the gimbal holding the probe normal to the surface, and a second portion with a set of three shafts within a housing for urging the gimbal and probe against the surface. The second portion contains a potentiometer connected by another shaft to the first portion to measure the position of the first portion with respect to the second so that the second portion can be moved to place and maintain the shafts at the midpoint of their travel. Then, as irregularities in the surface are encountered, the first portion can respond by moving closer to or farther from the second portion. 7 figures.

  20. Robotic end effector

    DOEpatents

    Minichan, Richard L.

    1993-01-01

    An end effector for use in probing a surface with a robotic arm. The end effector has a first portion that carries a gimbal with a probe, the gimbal holding the probe normal to the surface, and a second portion with a set of three shafts within a housing for urging the gimbal and probe against the surface. The second portion contains a potentiometer connected by another shaft to the first portion to measure the position of the first portion with respect to the second so that the second portion can be moved to place and maintain the shafts at the midpoint of their travel. Then, as irregularities in the surface are encountered, the first portion can respond by moving closer to or farther from the second portion.

  1. End of life issues.

    PubMed

    Sykes, Nigel

    2008-05-01

    Despite advances in cancer survival rates, end of life care remains a vital aspect of cancer management. The use of integrated care pathways can facilitate effective care of dying patients in a generalist setting. However, it remains important that staff are able to recognise the onset of the dying process, not only in order to make symptom control provision, but also that appropriate communication can occur with patients and those close to them. This allows the exercise of choice over place and style of care. The key symptoms at the end of life are restlessness, agitation, breathlessness, pain and noisy respiration from retained airway secretions. Ethical tensions arise from the assumptions that the use of opioids and sedatives hastens dying, but this is contradicted by available evidence.

  2. Robotic end effector

    SciTech Connect

    Minichan, R.L.

    1991-12-31

    This invention is comprised of an end effector for use in probing a surface with a robotic arm. The end effector has a first portion that carries a gamble with a probe, the gamble holding the probe normal to the surface, and a second portion with a set of three shafts within a housing for urging the gamble and probe against the surface. The second portion contains a potentiometer connected by another shaft to the first portion to measure the position of the first portion with respect to the second so that the second portion can be moved to place and maintain the shafts at the midpoint of their travel. Then, as irregularities in the surface are encountered, the first portion can respond by moving closer to or farther from the second portion.

  3. End of Mission Considerations

    NASA Technical Reports Server (NTRS)

    Hull, Scott M.

    2013-01-01

    While a great deal of effort goes into planning and executing successful mission operations, it is also important to consider the End of the Mission during the planning, design, and operations phases of any mission. Spacecraft and launch vehicles must be disposed of properly in order to limit the generation of orbital debris, and better preserve the orbital environment for all future missions. Figure 30-1 shows a 1990's projected growth of debris with and without the use of responsible disposal techniques. This requires early selection of a responsible disposal scenario, so that the necessary capabilities can be incorporated into the hardware designs. The mission operations must then be conducted in such a way as to preserve, and then actually perform, the planned, appropriate end of mission disposal.

  4. ARIEL front end

    NASA Astrophysics Data System (ADS)

    Marchetto, M.; Baartman, R. A.; Laxdal, R. E.

    2014-01-01

    The ARIEL project at TRIUMF will greatly expand the variety and availability of radioactive ion beams (RIBs) (Laxdal, Nucl Inst Methods Phys Res B 204:400-409, 2003). The ARIEL front end connects the two ARIEL target stations to the existing ISAC facility to expand delivery to two and eventually three simultaneous RIB beams with up to two simultaneous accelerated beams (Laxdal et al. 2008). The low-energy beam transport lines and mass separators are designed for maximum flexibility to allow a variety of operational modes in order to optimize the radioactive ion beam delivery. A new accelerator path is conceived for high mass delivery from an EBIS charge state breeder. The front-end design utilizes the experience gained in 15 years of ISAC beam delivery.

  5. Robotic Arm End Effector

    NASA Technical Reports Server (NTRS)

    2008-01-01

    Image illustrates the tools on the end of the arm that are used to acquire samples, image the contents of the scoop, and perform science experiments.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  6. How Insurgencies End

    DTIC Science & Technology

    2010-01-01

    Angola, or National Union for the Total Independence of Angola USMC U.S. Marine Corps VC Vietcong USSR Union of Soviet Socialist Republics WTC World...prevail, the end game tends to be foreshortened, and, in many instances, contemporaneous observers did not detect the government’s impending collapse ...insurgency begins to collapse , the conflict often “slows down” (McCormick, Horton, and Figure 2.2 Arc of Insurgent Defeat SOURCE: McCormick, Horton

  7. 78 FR 76758 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Reef Fish Fishery of the Gulf of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-19

    ...NMFS announces the closure date of the recreational season for red snapper in the exclusive economic zone (EEZ) of the Gulf of Mexico (Gulf) for the 2014 fishing season through this temporary rule. Federal waters of the Gulf will close to red snapper recreational harvest at 12:01 a.m., July 11, 2014. This closure is necessary to prevent the recreational sector from exceeding its quota for the......

  8. Unique cloud pattens, Gulf of Oman

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The wind currents off Ras (Cape) al Hadd, Oman cause interesting cloud patterns over the Gulf of Oman (23.5N, 60.0E). Meteorologists assert that the cloud patterns are the effect of the peculiar combination of heat from the deserts, being funneled by the mountains, toward the topography of the coastal headlands, clashing with the prevailing ocean breezes and varying sea conditions all coming together in this restricted location.

  9. The Persian Gulf Region. A Climatological Study

    DTIC Science & Technology

    1990-05-01

    in .01 .00 0 00, .0 IF Ln Ln N 11 6 1N C14 W) cm In C4 0 C4 cc 10 wl LS ( Dcm A v W) In in in 19 Sky Cover. Well-developed high and middle cloud _O__N...of a Phantom in the Desert," Weather, Vol. 41, No. 2, pp. 57-61, 1986. 0 62 ERRATA--MAY 1989 USAFETAC/TN-88/002 THE PERSIAN GULF -REGION A

  10. Petroleum geology of the Gulf of Aden

    SciTech Connect

    Allen, R.B ); Sikander, A.H. ); Abouzakhm, A.G.

    1991-08-01

    Evaluation of eight wells (seven offshore and one onshore) in Yemen and nine wells (two offshore and seven onshore) in Somalia, and a regional interpretation of all geophysical data available from ministry files in Yemen and Somalia has been carried out under the auspices of the World Bank-executed Red Sea/Gulf of Aden Regional Hydrocarbon Study Project. A northwest-southeast pre-Oligocene structural trend affecting the onshore pre-rift Mesozoic and early Tertiary rocks has been overprinted in the offshore by an east-west-trending extensional fault system forming the Gulf of Aden, and segmented by a series of northeast-southwest-trending left-lateral sets of transform faults. Free oil 42-44 API was recovered from Sharmah-1 well from the Eocene Habshiya limestone in Yemen and from the Late Jurassic Wanderer limestone (10-35{degree} API) at Dagah Shabei-1 well in Somalia. Geochemical analyses performed on well cuttings and a review of company data identify oil-sourcing potential in the pre-rift Upper Jurassic, Lower to Upper Cretaceous, and Paleocene to Eocene in Yemen, and Upper Jurassic and Upper Cretaceous in Somalia. The geothermal gradients (3.5C/100m) and maturation data (vitrinite reflectance, thermal alteration index, and T{sub max}) in the Gulf of Aden wells in the Yemen and Somali offshore imply that the oil window is relatively shallow (1,750-3,500 m). Relatively thin Paleogene in the Gulf of Aden area suggests that the Mesozoic and Lower Tertiary sediments which contain multiple source and reservoir sequences are situated within the oil window, and thus are highly prospective for oil and gas.

  11. OCEANOGRAPHY OF THE GULF OF MEXICO.

    DTIC Science & Technology

    Gulf of Mexico which has been carried on during the past year. Included are reviews of work in physical oceanography, geophysics, geology, geo-chemistry, chemistry, instrumentation, and biofouling. Attention is called to the fact that several special reports have been issued by individual investigators that discuss specific research activities in greater detail. The field work carried out aboard the R/V ALAMINOS is summarized, and publications, papers, and reports resulting from the work are presented.

  12. Winter Shamal in the Persian Gulf

    DTIC Science & Technology

    1979-08-01

    data at each location. Other evidence, however, such as wind reports from the oil rig Seashell located between Halul Island and the east shore of the...Figure A-12d). By 24/15Z, observers at oil rig Seashell -- located east of the Qatar Peninsula at approximately...to 40 kt were commonplace, as indicated by surface observations at the oil rigs and islands in the Gulf. Rig Seashell (near the Qatar Peninsula at

  13. Oxygen Sag and Stream Purification.

    ERIC Educational Resources Information Center

    Neal, Larry; Herwig, Roy

    1978-01-01

    Presents a literature review of water quality related to oxygen sag and stream purification, covering publications of 1976-77. This review includes: (1) self-purification models; (2) oxygen demand; and (3) reaeration and oxygen transfer. A list of 60 references is also presented. (HM)

  14. POPULATION DECLINE IN STREAM FISH

    EPA Science Inventory

    Over half of the streams in the Mid-Atlantic Highlands have fish communities that are in fair or poor condition, and the EPA concluded that physical habitat alteration represents the greatest potential stressor across this region. A quantitative method for relating habitat quali...

  15. ALIENS IN WESTERN STREAM ECOSYSTEMS

    EPA Science Inventory

    The USEPA's Environmental Monitoring and Assessment Program conducted a five year probability sample of permanent mapped streams in 12 western US states. The study design enables us to determine the extent of selected riparian invasive plants, alien aquatic vertebrates, and some ...

  16. Video Streaming in Online Learning

    ERIC Educational Resources Information Center

    Hartsell, Taralynn; Yuen, Steve Chi-Yin

    2006-01-01

    The use of video in teaching and learning is a common practice in education today. As learning online becomes more of a common practice in education, streaming video and audio will play a bigger role in delivering course materials to online learners. This form of technology brings courses alive by allowing online learners to use their visual and…

  17. Diagnostic tools for mixing models of stream water chemistry

    USGS Publications Warehouse

    Hooper, R.P.

    2003-01-01

    Mixing models provide a useful null hypothesis against which to evaluate processes controlling stream water chemical data. Because conservative mixing of end-members with constant concentration is a linear process, a number of simple mathematical and multivariate statistical methods can be applied to this problem. Although mixing models have been most typically used in the context of mixing soil and groundwater end-members, an extension of the mathematics of mixing models is presented that assesses the "fit" of a multivariate data set to a lower dimensional mixing subspace without the need for explicitly identified end-members. Diagnostic tools are developed to determine the approximate rank of the data set and to assess lack of fit of the data. This permits identification of processes that violate the assumptions of the mixing model and can suggest the dominant processes controlling stream water chemical variation. These same diagnostic tools can be used to assess the fit of the chemistry of one site into the mixing subspace of a different site, thereby permitting an assessment of the consistency of controlling end-members across sites. This technique is applied to a number of sites at the Panola Mountain Research Watershed located near Atlanta, Georgia.

  18. The Implications of the Possible End of the Arab-Israeli Conflict for Gulf Security,

    DTIC Science & Technology

    1997-01-01

    Future Fault Lines 87 B . The State of U.S.-Israel Cooperation Today 91 C. On Weapons of Mass Destruction 93 Bibliography 99 FIGURES 5.1...Riedel, Alina Romanowski, Mohammed al Sabah, James Schlesinger, Fred Smith, David Welch, and Paul Wolfowitz, as well as others both in the United...and growing. The American Petroleum Institute pegged oil imports at a record 10,059,000 barrels per day ( b /d) for July 1994. The previous record

  19. Runoff characteristics of California streams

    USGS Publications Warehouse

    Rantz, S.E.

    1972-01-01

    California streams exhibit a wide range of runoff characteristics that are related to the climatologic, topographic, and geologic characteristics of the basins they drain. The annual volume of runoff of a stream, expressed in inches, may be large or small, and daily discharge rates may be highly variable or relatively steady. The bulk of the annual runoff may be storm runoff, or snowmelt runoff, or a combination of both. The streamflow may be ephemeral, intermittent, or perennial; if perennial, base flow may be well sustained or poorly sustained. In this report the various runoff characteristics are identified by numerical index values. They are shown to be related generally to mean annual precipitation, altitude, latitude, and location with respect to the 11 geomorphic provinces in the California Region. With respect to mean annual precipitation on the watershed, streamflow is generally (1) ephemeral if the mean annual precipitation is less than 10 inches, (2) intermittent if the mean annual precipitation is between 10 and 40 inches, and (3) perennial if the mean annual precipitation is more than 40 inches. Departures from those generalizations are associated with (a) the areal variation of such geologic factors as the infiltration and storage capacities of the rocks underlying the watersheds, and (b) the areal variation of evapotranspiration loss as influenced by varying conditions of climate, soil, vegetal cover, and geologic structure. Latitude and altitude determine the proportion of the winter precipitation that will be stored for subsequent runoff in the late spring and summer. In general, if a watershed has at least 30 percent of its area above the normal altitude of the snowline on April 1, it will have significant snowmelt runoff. Snowmelt runoff in California is said to be significant if at least 30 percent of the annual runoff occurs during the 4 months, April through July. Storm runoff is said to be predominant if at least 65 percent of the annual

  20. Tidal characteristics of the gulf of Tonkin

    NASA Astrophysics Data System (ADS)

    Minh, Nguyen Nguyet; Patrick, Marchesiello; Florent, Lyard; Sylvain, Ouillon; Gildas, Cambon; Damien, Allain; Van Uu, Dinh

    2014-12-01

    The Gulf of Tonkin, situated in the South China Sea, is a zone of strong ecological, touristic and economic interest. Improving our knowledge of its hydro-sedimentary processes is of great importance to the sustainable development of the area. The scientific objective of this study is to revisit the dominant physical processes that characterize tidal dynamics in the Gulf of Tonkin using a high-resolution model and combination of all available data. Particular attention is thus given to model-data cross-examination using tidal gauges and coastal satellite altimetry and to model calibration derived from a set of sensitivity experiments to model parameters. The tidal energy budget of the gulf (energy flux and dissipation) is then analyzed and its resonance properties are evaluated and compared with idealized models and observations. Then, the tidal residual flow in both Eulerian and Lagrangian frameworks is evaluated. Finally, the problem of tidal frontogenesis is addressed to explain the observed summer frontal structures in chlorophyll concentrations.